University of Alaska 

Coastal Marine Institute 

Annual Report No. 2 

Fiscal Year 1995 

OCS Study MMS 95-0057 
OCS Study MMS 95-0057 

University of Alaska Coastal Marine Institute 

In Cooperation: 

Minerals Management Service 

University of Alaska Fairbanks 

State of Alaska 

Annual Report 

Fiscal Year 1995 

Agreement Number 14-35-0001-30661 

Submitted by Vera Alexander 

Director, UA CMI 

To: 

U.S. Department of the Interior 

Minerals Management Service 

Alaska OCS Region 

December 1995 

Contents 

Introduction .......................... .................................................................................................. 1 

Microbial Degradation of Aromatic Hydrocarbons in Marine Sediments 

Joan R Braddock .................................................................................................................. .4 

Intertidal and Subtidal Effects of Pollution: 

Assessment of Top-trophic Level Predators as Bioindicators 

Lawrence K. Dual R. Terry Bowyer, James B. Faro, andDanielD. Roby .................................... 15 

A Study of the Adsorption and Biodegradation of Aromatic Hydrocarbons by Marine Sediments 

Susan M. Henrichs and Michelle Luoma ................................................................................. 32 

Kachemak Bay Experimental and Monitoring Studies 

Raymond C. Highsmith, Tama L. Rucker, and Susan M. Saupe .................................................. 44 

North Slope Amphidromy Assessment 

Thomas C. Kline and JohnJ Goering ..................................................................................... 55 

Recruitment of Juvenile Flatfishes in Alaska: Habitat Preference at Kodiak Island 

Brenda L. Norcross .............................................................................................................. 68 

Juvenile Flatfish Habitat in Kachemak Bay: A Pilot Study 

Brenda L. Norcross .................................................................................................................... .77 

Testing Conceptual Models of Marine Mammal Trophic Dynamics 

Using Carbon and Nitrogen Stable Isotope Ratios 

Donald M. Schell.. ............................................................................................................... 86 

Circulation on the North Central Chukchi Sea Shelf 

ThomasJ Weingartner ................................... .... .................................................................. 97 

Winter Circulation Processes in the Northeast Chukchi Sea 

ThomasJ Weingartner ..................... ... ..................................................................... 111 

New Projects .......................... ................................................................................................ 119 

Funding Summary ....................................................................................................................... 121 
Introduction 

The University of Alaska Coastal Marine Institute (CMI) produced its first 

Annual Report in 1994 to introduce the new organization. Since most of the 

research supported in fiscal year 1994 began in the spring of that year, and since 

no scientific results were available, the first Annual Report outlined the proposed 

work with a series of abstracts, one for each project being funded. In this 1995 

Annual Report the CMI is pleased to present the preliminary scientific findings 

of the ten Alaskan CMI-funded projects as well as abstracts for two additional 

projects that received funding in 1995. This report demonstrates that the University of Alaska CMI has been active in addressing many of the marine science 

related research needs of the State of Alaska and the Minerals Management 

Service (MMS). 

Background 

MMS administers the Outer Continental Shelf (OCS) natural gas, oil, and 

marine minerals program, which oversees the safe and environmentally sound 

leasing, exploration, and production of these resources within our nation's offshore areas. The Environmental Studies Program (ESP) was formally directed in 

1978, under Section 20 of the OCS Lands Act Amendments, to provide information for decisions involving the planning, leasing, and management of exploration, development, and production activities. The research agenda is driven by the 

identification of specific issues, concerns, or data gaps by federal decision makers 

and state and local governments who participate in the process. ESP research 

focuses on the following broad issues associated with the development of OCS 

gas, oil, and minerals: 

What are the fates and effects of potential OCS-related pollutants (e.g., 

oil, noise, drilling muds and cuttings, products of fuel combustion) in the 

marine and coastal environment and the atmosphere? 

What biological resources (such as fish populations) exist, and what 

resources are at risk? What is the nature and extent of the risk? What 

measures must be taken to allow extraction to take place? 

How do the OCS activities affect people in terms ofjobs and the 

economy? What are the direct and indirect effects on local culture? What 

are the psychological effects of the proposed OCS activities? 
Because MMS and individual states have distinct but complementary roles in the 

process that leads to decisions, scientific information is needed by MMS, the 

states, and localities potentially affected by CMI operations. In light of this, 

MMS has developed a locally managed CMI program. Under this program, 

MMS will take advantage of highly qualified, scientific expertise at local levels in 

order to: 

Collect and disseminate environmental information needed for OCS oil 

and gas and marine minerals decisions; 

Address local and regional OCS-related environmental and resource 

issues of mutual interest; and 

Strengthen the partnership between MMS and the states by addressing 

OCS oil and gas and marine minerals information needs. 

MMS and the State of Alaska have joined in a five-year (1993-97) renewable 

Cooperative Agreement to establish a CMI to be administered by the University 

of Alaska Fairbanks School of Fisheries and Ocean Sciences, to address some of 

these concerns and share the cost of research of mutual interest. Alaska was 

selected as the location for this CMI because it contains some of the major 

potential offshore oil and gas producing areas in the United States. The University of Alaska Fairbanks is uniquely suited to participate in this venture by virtue 

of its flagship status within the state and its nationally recognized scope and 

depth of marine and coastal expertise relevant to the broad range of OCS program information needs. In addition, MMS and the University of Alaska have 

worked cooperatively on ESP studies for many years. Research projects funded by 

the CMI are required to have at least one active University of Alaska investigator. 

However, cooperative research between the University of Alaska scientists and 

various state agencies are encouraged. 

A series of "Framework Issues" was developed during the formation of the CMI. 

This list of issues serves to identifjr and bracket the concerns to be addressed by 

the CMI. The Framework Issues have been identified as: 

I) Studies to improve understanding of the affected marine, coastal, or 

human environment; 

2) Modeling studies of environmental, social, and economic processes to 

improve predictive capabilities and to define information needs; 

3) Experimental studies to improve understanding of environmental processes or the causes and effects of OCS activities; 

4) Projects which design or establish mechanisms or protocols for the 

sharing of data or information regarding marine or coastal resources or 

human activities to support prudent management of oil and gas and 

marine mineral resources; 

5) Synthesis studies of background information; and 

6) Descriptive studies of offshore mining technologies. 
Projects funded through the CMI will concentrate on providing information 

which can be used by the MMS and the state for management decisions specifically relevant to MMS mission responsibilities. That is, projects will be pertinent 

to either the OCS oil and gas program or the marine minerals mining program 

and should provide useful information for one of the phases of program management, or for the scientific understanding of the potential environmental effects of 

these resource development activities in arctic and subarctic environments. 

Additional guidelines given to prospective researchers presently identify the Cook 

Inlet and Shelikof Strait areas as well as the Beaufort and Chukchi Seas as areas 

of primary concern to MMS and the state. 

The proposal process is initiated each year with a request for letters of intent to 

address one or more of the Framework Issues stated above. This request is sent to 

researchers at the University of Alaska and to various state agencies. A CMI 

technical committee then decides which of the proposed letters of intent should 

be developed into proposals to be evaluated for possible funding. 

Successful investigators are strongly encouraged to publish their results in 

peer-reviewed journals and to present them at national meetings. In addition, 

some investigators will also present information directly to the public in seminars. 

Alaskans will benefit fiom the examination and increased understanding of the 

processes unique to Alaskan OCS and coastal waters because this enhanced 

understanding can be applied to other problems besides oil, gas, and mineral 

extraction. Spin-offs will likely benefit such activities as subsistence fisheries and 

northern shipping. 

Project Reports 

Many of the CMI-funded projects address some combination of issues related to 

fisheries, biomonitoring, physical oceanography and the fates of oil. In the 

following section, the CMI project reports have been placed in alphabetic order 

by author. For the convenience of the reader, an abstract is provided at the 

beginning of each contribution. The conclusions presented here should be 

considered preliminary since most projects are ongoing. 
Microbial Degradation of Aromatic 

Hydrocarbons in Marine Sediments 

Joan F. Braddock 

Institute of Arctic Biology 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7000 

Abstract 

Introduction 

It has been estimated that 2-9 million tons of oilpollutants enter the marine system 

yearlyj-om various sources worldwide. A number ofphysical-chemicalprocesses 

afect the fate of these petroleum inputs, including adsorption of oil toparticulate 

material. Microbial degradation ofpetroleum hydrocarbons is a major mechanism 

for the removal of oilj-om the environment, yet there are conzicting data regarding 

how adsorption afects both the rate and extent of biodegradation of hydrocarbon 

?actions. Polycyclic aromatic hydrocarbons are of sign$cant concern in the environment due to their relative toxicity. Therefore, the initial focus has been on the 

aromatic hydrocarbon phenanthrene. It was found that populations ofphenanthrene 

degraders are present in sediments collected in Cook Inlet. Their presence is likely 

related to naturally-occurring carbon substrates chemically similar to phenanthrene. 

It was also found that these populations could actively mineralize phenanthrene in 

sediment slurry microcosms. Phenanthrene adsorbs to these sediments and is not 

readily extracted by organic solvents. Radiolabeledphenanthrene is now being used 

to begin to determine the biodegradability of adsorbed hydrocarbonj-actions. Two 

approaches are being used to study the interactions between microorganisms and 

hydrocarbons in sediment slurries. Thejrst is a kinetic approach and the second is a 

bioassay. An understanding of the interactions between sorbed hydrocarbons and 

microbial communities is critical to assessing the fates and efects of both chronic and 

acute oil inputs to the marine environment. 

Crude oil or refined petroleum products released at sea are subject to a number of 

physical-chemical and biological processes. These include "... evaporation, 

dissolution of specific components, dispersion, ingestion of oil droplets by pelagic 

organisms, oil adsorption onto suspended particulate material, photochemical 

oxidation of surface films, microbial degradation and removal by advective 

processes" (Payne et al., 1987). Some of these processes are well understood and 

can be incorporated into contaminant fate models. Other processes, such as the 

rates and extent of biodegradation, have been less well quantified. Nevertheless, 

the microbial degradation of petroleum hydrocarbons is known to be a major 

mechanism for removal of these compounds from the environment (Leahy and 
Colwell, 1990). A number of studies have examined the potentials for microbial 

degradation of hydrocarbons in sediments either contaminated by acute inputs, 

such as from major oil spills (Colwell et al., 1978; Ward et al., 1980; Karl, 199z), or 

by additions of relatively high concentrations of hydrocarbons to sediments in 

laboratory studies (Bauer and Capone, 1985; 1988) or to outdoor wave tanks 

(Payne et al., 1984). Hundreds of marine sediment samples collected following the 

Exxon Valdez oil spill were assayed for microbial populations and activity 

(Braddock et al., 1993; Braddock et al., 1995). Much of the research to date has 

focused on microbial degradation and mineralization of relatively high concentrations of hydrocarbons. Chronic inputs may be of the greatest concern to the 

environment. However, the effects of these low-level additions are harder to 

quantify (Boesch et al., 1987). 

Inputs of aromatic hydrocarbons have been of particular concern because many of 

these compounds are toxic, and some are potent mutagens and carcinogens. 

Generally, aromatic hydrocarbons are characterized as being relatively insoluble in 

water, and many of these compounds are also strongly adsorbed by soils and 

sediments (Means et al., 1980). In addition, polycyclic aromatic hydrocarbons 

(PAH) can also bind to microorganisms. By this mechanism, mobile microorganisms may enhance transport of PAHs in some systems (Jenkins and Lions, 1993). 

Microbial transformations in aquatic systems appear to be very important in 

influencing the transport of two- and three-ring PAHs (Herbes and Schall, 1978). 

For these reasons, this study focuses on the bioavailability of the PAH, phenanthrene, in marine sediment. 

A number of studies have reported a positive correlation between the numbers of 

hydrocarbon-degrading microorganisms and oil pollution patterns in marine 

systems polluted by hydrocarbons (Colwell et al., 1978; Roubal and Atlas, 1978; 

Ward et al., 1980; Braddock et al., 1993; Braddock et al., 1995). Less often, hydrocarbon degraders may be present as a result of exposure to other chemically 

similar compounds in the environment. Seawater samples from Resurrection Bay, 

Alaska, were found to have high levels of hydrocarbon oxidization activity, which 

is, at least partly, a result of the presence of naturally occurring terpenes in those 

waters (Button, 1984; Button and Juttner, 1~8~). Thecomposition of the microbial 

population has implications for the likely effects of acute or chronic oil inputs in 

ecosystems. For example, Heitkamp and Cemiglia (1~87) found that PAH 

residues persisted two to four times longer in pristine ecosystems than in oil 

polluted ecosystems. 

Another study which is relevant to the work described here was conducted in the 

early 1980s by Payne ct al. (1984) on sediments collected from Kasitsna Bay, 

Alaska. The main objective of these studies was to investigate the rates and extent 

of physical and chemical changes which occur after a major petroleum spill in a 

subarctic marine system. While not the major focus of their study, Payne et al. did 

conduct outdoor experiments in flow-through wave tanks containing sea water at 
Kasitsna Bay to assess the impact of biodegradation on oil transformations for 

the oil weathering model they developed. High concentrations of oil were used to 

mimic the short-term effects of a large oil spill. The Payne et al. study did not 

specifically address the effects of adsorption on degradation of hydrocarbons, but 

it did look at overall short-term biodegradation. They found that the degradation 

was greatest in the summer (due to increased temperature) and occurred primarily on oiled surfaces. Payne et al. concluded that dissolution removed more oil 

than biodegradation, a result they attributed to the short residence time in the 

wave tanks. However, they conceded that microbial degradation is likely to be a 

more important component for long-term oil transformations in marine systems. 

It is generally thought that sorption of hydrocarbons decreases the availability of 

PAH for microbial degradation (Manilal and Alexander, 1991; Weissenfels et al., 

1992), but a few studies have provided evidence that sorbed compounds may be 

utilizable by some microorganisms (Fu and Alexander, 1992; Guerin and Boyd, 

1992; Knaebel et al., 1994). Guerin and Boyd found large differences between two 

naphthalene-degrading bacteria in utilization of sorbed naphthalene. Sorption 

limited the rate and extent of biodegradation for the first microorganism, but 

enhanced total degradation for the second. Adsorption effects on bioavailability 

are not yet well understood. The effects depend upon the chemical nature of the 

sorbant, the mechanisms of sorption, the time allowed for equilibrium, and the 

properties of the associated microbial community. Adsorption of phenanthrene 

by marine sediments has recently been examined in another Coastal Marine 

Institute (CMI) study by Henrichs, and is presented elsewhere in this Annual 

Report. Henrichs found that phenanthrene is strongly adsorbed by Jakolof Bay 

sediments, and that the process is rapid with much of the adsorption occurring in 

less than fifteen minutes. The overall objective of this present study is to begin to 

understand the response of marine sediment microbial communities to low-level 

inputs of aromatic hydrocarbons. This report discusses the results of the first ten 

months of this project. This project has also funded the training of one M.S. 

student. 

Methods 

Sample Collection 

Sediments were collected on July 22,1994 from the north shore of the eastern end 

(mouth) of Jakolof Bay. This bay is located near the Kasitsna Bay Research 

Laboratory on Lower Cook Inlet. The sediments are from the mudflats and are 

reasonably typical of intertidal sediments located throughout the Lower Cook 

Inlet region. Sediments were selected for their relative homogeneity, lack of 

macro-biological organisms, and for the presence of an easily collectible oxic 

layer. The sediments have not been particle-analyzed, but are fine in texture with 

a large silt component. Sediment samples were collected both for use in this 
project and for the CMI project of Henrichs. Sediments were kept on ice until 

they were transported to Fairbanks for processing. 

Microbial Populations 

Microbial populations of total heterotrophic microorganisms, hydrocarbon 

emulsifiers, and phenanthrene degraders were measured in freshly (within 48 

hours of collection) collected sediment. Total heterotrophs were measured using a 

marine broth medium (Difco) in 24-well cell well plates (Corning) with a most 

probable number method (MPN) (Lindstrom et al., 1991). Sheen screen MPNs 

(Brown and Braddock, 1990) were used to assay the proportion of the population 

able to emulsifjr crude oil. Phenanthrene degraders were enumerated by a fivetube MPN procedure based on addition of 14C-labeled phenanthrene as a sole 

carbon source to a series of MPN vials. Sediment was first diluted 1:10 in a 

Bushnell-Haas medium (Difco) amended with 2.5% NaC1. A 10-fold dilution 

series was set up with 5 replicate 40 mL septa vials (I-Chem Research) prepared 

for each dilution. Each vial was inoculated with 50 j.d of phenanthrene (2 g/L in 

acetone; final concentration 10 pg/mL slurry; containing about 50,000 dpm 

9-14C phenanthrene). Abiotic controls were prepared both by autoclaving some 

vials and by adding 1 mL 10 N NaOH at time zero to other vials. The vials were 

incubated for two weeks then "killed" with the NaOH. The 14C02 was recovered 

by acidifjring the vials with 1.5 mL concentrated HCl and purging the COz with 

a stream of nitrogen into a CO2-sorbing cocktail (see Brown et al., 1991). Vials 

containing C02 levels two times that of those measured in the abiotic controls 

were scored as positive for activity (Roubal and Atlas, 1978). This method was 

selected because it provided enough sensitivity to measure the populations. 

Microbial Activity Measurements/Kinetics Studies 

Microbial activity measurements were made using radiolabeled hydrocarbons 

(phenanthrene) in a manner similar to previous studies with sediment slurries 

(Braddock et al., 1993 after Brown et al., 1991). Duplicate vials of sediment 

slurries (concentrations specified for individual experiments) in a mineral salts 

medium (Bushnell-Haas medium amended with 2.5% NaCL; Atlas, 1~94) were 

injected with phenanthrene in acetone (concentrations specified for individual 

experiments) with 9-14C labeled phenanthrene added (about 50,000 dpm per 

aliquot). Immediately after injecting the vials with radiolabled phenanthrene, 

1 mL of 10 N NaOH was injected into a series of vials at time zero to stop 

microbial activity and trap COz. The remaining vials were incubated for specified 

periods and then "killed" by adding the NaOH. Other chemical inhibitors of 

microbial activity were also used, including autoclaving and the addition of 200 

mg/L (final concentration) sodium azide. The CO2 was then recovered by adding 

1.5 mL HC1 to each vial and purging the released C02 via a nitrogen stream into 

a CO2-sorbing cocktail. All final values were corrected for any label detected from 

abiotic controls. 
The fate of phenanthrene in sediment added to Jakolof Bay sediment slurries was 

also examined by radiorespirometry. After incubation, 14C-C02 was collected by 

removing 0.5 mL of headspace and 0.5 mL of supernatant with a gas-tight 

syringe (Hamilton). This aliquot was then added to a fresh vial containing 1 mL 

of concentrated HC1. The 14C-C02 evolved was either collected in 

phenethylamine on filter paper in a center well, or by purging with nitrogen as 

previously described. Dissolved phenanthrene was recovered by first centrifuging 

the I-chem vial at 5000 x g for 5 minutes, then removing the supernatant and 

placing it in a fresh vial. The remaining sediment was then rinsed with 10 mL of 

mineral salts medium (Bushnell-Haas medium amended with 2.5% NaC1; Atlas, 

1994), centrifuged again, and the supernatant removed. The supernatant was 

extracted by adding either 5 mL of benzene or 5 mL of methylene chloride, 

vortexing and removing 1 mL of the organic solvent for counting. The sediment 

remaining was extracted with three rinses of either benzene or methylene chloride, and then the aliquot was counted. Different solvent systems were used to 

optimize the extraction efficiency. 

Bioassay Development 

Phenanthrene degraders were isolated from enrichment cultures of freshly 

collected Jakolof Bay sediment. Four isolates were obtained using a spray plate 

protocol (Kiyohara, 1982). The isolates were then grown on a nutrient broth until 

dense. Standard curves of absorbance vs. cell number were made with standard 

plate count methods. The organisms were then grown to a standard optical 

density and the phenanthrene degradation activity measured as described earlier. 

Results and Discussion 

Three groups of microbial populations were measured in Jakolof Bay sediments, 

including total heterotrophs, phenanthrene degraders, and hydrocarbon emulsifiers (Table I). Total heterotrophs were about 2 x lo6 per g sediment. For comparison, a direct count of total microorganisms in sediments from this same part of 

Cook Inlet found about 10' microorganisms/g sediment (Atlas et. al., 1983). Total 

Table I. Microbial populations in Jakolof Bay sediments (three replicate samples) collected July 1994. 

Sample HC-emulsiiers Phenanthrene Deg. Heterotrophs 

(cells/g sediment) 

1 (20 1.7 x 103 1.7 x lo6 

2 (20 9.4 x lo1 1.7 x lo6 

3 (20 3.4 x lo1 2.2 x lo6 

Median (20 9.4 x 101 1.7 x 106 
bacteria, as measured by direct count microscopy, also found about 10'-lo8 

microorganisms/g sediment in Prince William Sound sediments (Braddock et al., 

1993). Direct counts typically yield higher numbers than culture methods since 

culturing methods only measure active microorganisms that can grow under the 

conditions provided. Either approach can be used to monitor the relative magnitude of the heterotrophic population. Hydrocarbon degraders, as determined by 

the sheen screen MPN, were found to be below the detection limits of the assay 

(<20/ g sediment). This is consistent with the use of this assay at other pristine 

marine sites (Braddock et al., 1995). However, using a radiorespirometric MPN 

procedure, Adas et d. reported between 10' and lo3 hydrocarbon utilizers in 

sediments from Lower Cook Inlet. The range measured by Atlas et al. more 

closely corresponds to the number of phenanthrene degraders enumerated in this 

study. Phenanthrene degraders were found to range fiom 10' to lo3. The populations of phenanthrene degraders may be related to the presence of naturally 

occurring aromatic compounds such as terpenes in the environment (Button, 

1984). The presence of these organisms also has implications for the fate of 

hydrocarbons entering this environment. Phenanthrene activity was also measured in freshly collected Jakolof Bay sediments (Figure I). Phenanthrene was 

mineralized at measurable rates after about a three-day lag phase. Phenanthrene 

utilization in the time course may be representative of the mineralization capacity 

of the naturally occurring population or may reflect an enrichment of the population of phenanthrene degraders to adapt to phenanthrene utilization under 

laboratory conditions. In previous experiments using a similar assay, it was found 

that PAH utilization after less than ten days incubation was reflective of the 

Time, days 

Figure I. Mineralization of I4C-labeled phenanthrene (10 g/mL) with time for freshly 

collected Jakolof Bay sediment slurries (1:lO sediment to mineral salts medium). The values 

are means of duplicate points, and the range in values is shown with error bars. 
capacity of the naturally occurring population to utilize that substrate (Brown et 

al., 1991). A similar time course experiment run with sediment stored in a freezer 

for about six months showed no activity for phenanthrene utilization even after 

30 days incubation, indicating that major population shifts occur in stored 

sediment (results not shown). Unfrozen sediment stored in a refrigerator began to 

go anaerobic shortly after collection. Therefore, to reflect processes occurring in 

the natural environment, laboratory work to determine microbial activity must be 

performed very soon after collecting fresh samples. 

In related mineralization experiments, several methods were used to attempt to 

complete a mass balance (Table 2). At the concentrations of sediment (1:lO wet 

weight sediment to nutrient-amended seawater) and phenanthrene (10 pg/mL) 

used in these experiments, only about 50% of the initial labeled phenanthrene 

could be accounted for. The residual 50% was apparently sorbed to sediment and 

was not readily extracted using benzene or methylene chloride. Concentrations of 

sediment and phenanthrene and extraction protocols developed by Henrichs will 

be used in the next set of experiments. Two methods of collecting COz were 

compared in this experiment: purging with nitrogen and collection in 

phenethylamine in a center well. Both methods recovered about the same amount 

of C02. In nine-day incubations, about 10% of the label was evolved as COz. No 

labelled COz was evolved after only one day of incubation. The dissolved concentration of phenanthrene measured (15% of the label added) corresponds to about 

1.5 mg/L, slightly higher than would be expected from the aqueous solubility of 

phenanthrene (about 1 mg/L in pure water at 298 K; Shaw, 1989), and may reflect 

the presence of other products of phenanthrene degradation or contaminants in 

the phenanthrene. The commercially prepared 14C-labeled phenanthrene used in 

these experiments and those of Henrichs may be contaminated by an unidentiTable 2. Fate of 9-I4C phenanthrene (10 pg/mL) in sediment slurries (1:lO wet sediment to nutrient-amended seawater) 

after one-day and nine-day incubations. Abiotic controls ("killed" at time zero) were subtracted from each prior to 

calculation of percentages. Each value represents nine replicate vials + 1 standard deviation. Method 1, COz acidified then 

purged with a nitrogen stream into CO2-sorbing cocktail. Method 2, CO2 collected on a phenethylamine-soaked filter 

paper in a center well. 

Fraction Method 1 Method 2 Method 2 

9-day 9-day 1-day 

% of radiolabeled phenanthrene added 

coz 

dissolved 

extracted from pellet 

total recovered 

'three seawater rinses 

2benzene extraction 

3methylene chloride ext. 
fied hydrocarbon (Henrichs, pers. comm.). Mass balance experiments in the 

absence of microbial activity have recently been completed in Henrichs' laboratory. As soon as fiesh sediment is collected in June 1995, the adsorption data 

collected from those experiments will be used to perform time course studies in 

the presence of the natural microbial populations. We have also begun to develop 

a bioassay for determining the bioavailability of phenanthrene in sediment 

slurries. Four phenanthrene degraders were isolated fiom fresh Jakolof Bay 

sediment collected in July 1994. These organisms have been characterized as 

Rhodococcus sp., Arthrobacter sp., and two Pseudomonas sp. Standard curves for 

growth, relating viable cell counts to absorbance, have been determined for each 

organism so that cultured organisms at specific population densities can be 

readily added to sediment slurries. These isolates all grow with phenanthrene as a 

sole carbon source on phenanthrene spray plates (Kiyohara et al., 1982). All of the 

isolates will also grow on a general heterotrophic medium. However, if they are 

grown for several generations on a general medium, they all lose their ability to 

mineralize phenanthrene. The activity of a constant biomass of these organisms is 

currently being determined in time course studies with 14C phenanthrene. Once 

the phenanthrene utilization kinetics of each organism are established, this suite 

of organisms can be used to look at the effect on sediment and bioavailability of 

phenanthrene in slurry experiments. It is hoped that this second approach to 

measuring bioavailability will help in understanding the effect of sedimentsubstrate-microorganism interactions on availability of PAH carbon substrates. 

Preliminary Conclusions 

Oil inputs to the marine environment have been studied intensively for the past 

several decades, and a number of processes have been identified that contribute to 

controlling the fate of these compounds in the marine environment. Some of 

these processes are fairly well understood, particularly for acute inputs of petroleum compounds. Other processes are less well understood and contradictory 

results have been reported, particularly where petroleum inputs are at low concentrations. Microbial transformations are often critical to the long-term fate of 

lower molecular weight aromatic hydrocarbons, but the degradability is likely to 

be affected by physical and chemical interactions of aromatics in sediments. The 

interactions between the microbial community and sorbed hydrocarbons may be 

very important in understanding the potential impacts of chronic petroleum 

additions to the marine environment. Further, microbial transformations may 

largely determine the persistence of compounds such as polycyclic aromatic 

hydrocarbons and thus affect their degree of hazard to the environment. The 

interactions between the extant microbial populations and the bioavailability of 

phenanthrene in sediment slurries from Lower Cook Inlet, Alaska, are beginning 

to be examined. These studies are important in predicting the fate of chronic and 

acute oil contamination to marine systems. 
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Intertidal and Subtidal Effects of Pollution: 

Assessment of Top-trophic Level Predators 

as Bioindicators 

Lawrence K. Duffy 

R. Terry Bowyer 

Daniel D. Roby 

Institute of Arctic Biology 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7000 

James B. Faro 

Alaska Department of Fish and Game 

Sitka, AK 99835-7563 

Abstract 

Pigeon guillemots (Cepphus columba) are well suited as bioindicators of contaminants in neritic food webs, because breedingpairs are wide4 dispersed andfeed on 

nearshore demersaljshes. Average productivity of 62 nests monitored in Kachemak 

Bay was 0.4Jledglingsper nest (Ma$eld method). Low egg survival (50%) and 

hatching rates of surviving eggs (76%) were responsible for poor overall hatching 

success (38%); 57-69% of the chicks that hatched survived to Jledgling. Predation 

was a major cause of nest failure. Diets ofguillemot nestlings were dominated by 

sand lance (46%), with smallerproportions of blennies (29%) and scu&ins (2%). 

Blood samples collected~om adults and nestlings (20 d and 30 dpost-hatch), 

showed haptoglobin values which rangedpom 0 to 282 mg/dL (mean = 103, SD = 

62.7). Mean levels d9ered among nests, but not between a&ha- and beta-chicks 

?om the same nest. However, haptoglobin levels did not dzfer among colonies, 

sampling dates, or nestling ages, nor were haptoglobin levels correlated with nestling growth performance. River otter latrine sites were documented and six animals 

were captured and sampled. These baseline biomarker values will aidfiture assessment of contaminant exposure. 

Introduction 

Focusing on the biological responses in indicator species overcomes many of the 

limitations that plague chemical analysis of the environment (Payne et al., 1987). 

While measuring body burdens is an important aspect of using higher vertebrates 

as biomonitors, equally important is the measurement of biomarkers because 

they: 

I) Provide evidence of exposure to compounds that do not bioaccumulate or 

are rapidly metabolized; 
2) Integrate the toxicological interactions resulting fiom exposure to complex 

mixtures of contaminants; 

3) Present a biologically relevant measure of the cumulative adverse effect; 

and 

4) Measure early responses of organisms to toxicant exposure and serve as 

short-term predictors of long-term adverse effects. 

Development of biomonitors will lead to a better understanding of environmental 

and ecosystem processes related to outer continental shelf (OCS) activities. In 

this research our primary focus is to develop the pigeon guillemot and the river 

otter as new indicators of environmental stress in nearshore marine ecosystems. 

Use of these bird and mammal models as upper trophic-level sentinels of 

bioavailable contaminants, such as oil, PCBs, and metals, will be developed to act 

as surrogates to estimate potential exposure and risk to humans living near sites 

of OCS activities (Fry and Lowenstine, 1985; Leighton 1985; Peakall et al., 1986). 

This research approach utilizes biomarkers (biochemical and cellular indicators of 

exposure), reproduction rates, and data on mortality to identify and quantify the 

present level of variability within the Lower Cook Inlet-Kachemak Bay ecosystem. This approach is necessary because evaluation of the potential for exposure 

to contaminants in the environment is extremely complex due to the differences 

in the biological availability of contaminants at different trophic levels and 

varying toxicological interactions within exposed organisms. 

Pigeon Guillemots 

Pigeon guillemots are one of the best-suited avian species for monitoring 

nearshore marine ecosystem health for several reasons: 

I) they are a common and widespread seabird species breeding in coastal 

Alaska, specifically in Lower Cook Inlet and Shelikof Straits (Sowls 

et al., 1978); 

2) they forage within 5 km of the nest site in the subtidal and nearshore 

zones (Drent, 1965); 

3) unlike most seabird species, they do not breed in large, dense colonies that 

are sensitive to disturbance; 

4) they raise their young almost entirely on fish, preying primarily on 

subtidal and nearshore bottomfish (blennies, sculpins), as well as a few 

schooling forage fish (e.g., sand lance; Drent, 1965); 

5) the one- or two-chick broods are fed in the nest until the young reach 

adult body size; and 

6) adults will breed in nest boxes, thus providing a readily accessible study 

population (Asbirk, 1979). 

Guillemots begin breeding at two years of age and adults have high annual 

survivorship (85% Asbirk, 1979). Young gudlemots normally return to the natal 
area to breed. Nest site fidelity of breeding pairs is high, and even in instances 

when pairs relocate nests, the distances involved are usually small (<30 m). Eggs 

are laid in a wide variety of natural crevices and holes, but most nest sites in the 

study area are located in cavities in cliffs or cracks in rock masses (G.C. West and 

D. Erikson, pers. comm.). Eggs are usually laid about 50 cm from the entrance of 

the nest crevice (Asbirk, 1979), thus the eggs, chicks and attending adults are 

normally accessible for data collection. Guillemots are unusual among alcids in 

that they normally lay two-egg clutches and raise two chicks per nesting attempt. 

Guillemots carry whole fish in their bills to the nest-site crevice to feed their 

young. Thus, individual prey items can be identified, weighed, measured, and if 

necessary, collected for contaminant analyses. 

Guillemots have served as subjects in previous studies to assess the effects of 

ingested crude oil on marine birds (Peakall et al., 1980). Nestling black guillemots 

(Cepphusgrylle), a very closely-related sibling species of the pigeon guillemot, 

were fed single doses of weathered South Louisiana crude oil (WSLC) and 

subsequently monitored in their natural nest site where they were cared for by 

their parents. These experiments demonstrated that single doses of as little as 0.1 

mL WSLC resulted in declines in growth rates, increases in plasma sodium 

levels, and increases in nasal and adrenal gland masses. The effects of the single 

dose were not transient, as nestlings that were dosed at roughly two weeks posthatch were 20% lighter than controls at five weeks of age (just prior to fledging). 

Such persistent sublethal effects may have serious consequences for post-fledgling 

survival. Peakall et al.'s (1~80) study clearly demonstrates that guillemot nestlings 

living normally in their chosen habitat are tolerant to the handling and disturbance associated with experiments designed for assessing pollutant toxicity. 

Because of the repeated transfer of marine prey captured by adults to their young, 

chicks act as a potential sink for petroleum hydrocarbons in contaminated prey. 

Mer a large oil spill at high latitudes, chronic consumption of polycyclic aromatic hydrocarbons (PAH) by adult guillemots and the accumulation of PAH in 

chicks would be expected to result in reproductive effects. Thus guillemot chicks 

provide a good model for investigating the impact of petroleum hydrocarbon 

exposure on seabird reproduction. The high molecular weight aromatic fi-action 

of crude oil is known to be the most persistent in the marine environment, and is 

also the causative agent in growth retardation and hypertrophy of adrenal and 

nasal glands in seabirds (Peakall et al., 1982). The assimilation, detoxification, and 

metabolism of PAH may interfere with the characteristic accumulation of lipid 

reserves in guillemot chicks. Presumably, chicks store assimilated aliphatic 

hydrocarbons from ingested crude oil in their large fat deposits. Much of these 

lipid reserves are metabolized by the chick prior to sea-going, at which time 

remobilized aliphatics may be pathogenic. In summary, guillemot chicks are well 

suited as models for monitoring sublethal effects of exposure to crude oil. 
River Otters 

River otters inhabiting marine environments also serve as excellent monitors 

since they make extensive use of, and concentrate their activities in, intertidal and 

subtidal zones (Dubuc et al., 1990; Larsen, 1984; Woolington, 1984). These high 

trophic-level carnivores are long-lived (2 12 years of age; Docktor et al., 1987), 

and occur at densities of 0.2-0.8 otters per km of shoreline throughout the Gulf 

of Alaska (Testa et al., 1994). River otters are extremely sensitive to aquatic 

pollutants (Table I), yet continued to reside within the area of oil-contaminated 

shorelines in Prince Wiam Sound, Alaska, following the Exxon Valdez oil spill 

(Testa et al., 1994). River otters commonly inhabit marine coastal environments, 

but have not been classified as marine mammals for purposes of the Marine 

Mammal Protection Act. Consequently, legal take permits are not required to 

conduct scientific research on this species. These characteristics make river otters 

an excellent model for assessing the effects of marine pollution on mammals, and 

provide an overall index to the health of the environment. 

River otters consume a diet dominated by marine fishes, which they prey upon in 

intertidal and subtidal zones, although they also consume a wide variety of 

marine invertebrates. Such nearshore areas are the most often affected by pollution. For instance, oil spilled &.om the Exxon Valdez contaminated extensive areas 

of the intertidal and subtidal environments, which was reflected in a loss of 

dietary diversity for otters inhabiting oil-contaminated shorelines (Bowyer et al., 

1995). Likewise, river otters living in oiled areas exhibited a significantly lower 

body mass (when controlled for sex and total body length) than did otters inhabiting oil-free areas (Duffj et al., 1993). Otters have extremely large home ranges 

(20-40 km of shoreline; Bowyer et al., 1995), and hence integrate the effects of 

pollution over wide areas. 

Table I. Published literature indicating river otters are especially sensitive to pollutants in aquatic systems. 

Pesticides Heavy Metals Cesium-137 PCBs Crude Oil 

Clark et al. 1981 Clark et al. 1981 Clark et al. 1981 Clark et al. 1981 Du@ et al. 1993 

Halbrook et al. O'Connor & Halbrook et al. Henney et al. Duf$ et al. 1994 

1981 Nielson 1981 1981 1981 

A nonlethal method for evaluating the effects of marine pollutants (in this 

instance, crude oil) on the blood-enzyme chemistry of river otters has already 

been developed (Duffj. et al., 1994). Blood haptoglobins (an acute-phase protein) 

were elevated in otters inhabiting areas where crude oil was prevalent one year 

following the oil spill (Duffj et al., 1993). Even two years after the oil spill and a 

major effort to clean oil-contaminated shores, a biostatistical model was successhlly constructed, using logistic regression, in which > 85% of river otters were 

correctly classified as having been captured in oiled or non-oiled zones. This 
highly sensitive model used only blood values for haptoglobin, interleukin-6 (a 

cytokine), and AST (a liver enzyme). The approach has already been extended for 

evaluating other marine mammals (Zenteno-Savin et al., 1993), and may be 

applicable to other vertebrates, especially marine birds. Coupling this knowledge 

of otters with similar physiological data for pigeon guillemots will provide a 

sensitive tool for examining the effects of pollution on the nearshore environment. 

Methods 

Field studies were conducted during the 1994 breeding season in Kachemak Bay, 

Alaska (Figure I). Approximately 500 pigeon guillemots nest along the shores of 

Kachemak Bay and the tributary bays on the south side of Kachemak Bay (Sowls 

et al., 1978). Active and accessible nests from Mallard Bay in the northeast to 

Seldovia Bay in the southwest were located and marked during the breeding 

season. These nests were closely monitored until the young fledged or the nesting 

attempt failed. From June to August, chicks that hatched in accessible nests were 

weighed regularly to determine individual growth rates throughout the nesting 

period. Alpha and beta nestlings were marked shortly after hatching for consistent identification throughout the nesting period. Blood samples (c. 1 mL ) were 

collected in heparinized vials by brachial vein puncture from each nestling at ages 

20 and 30 days post-hatch (guillemot chicks normally fledge at 30-40 days posthatch). The whole blood was centrifuged and the plasma frozen at -200C for later 

analyses in the lab. Blood samples were analyzed for plasma protein, haptoglobins 

and IL-6. Twelve 30-day-old nestlings were collected for P450 assays. The 

taxonomic composition of guillemot diets was determined, with the aid of 15-60x 

spotting scopes, by observing adults transporting nestling meals in their bills. 

River otters, which are moderately abundant in Kachemak Bay, were captured 

using Hancock live traps (Duffy et al., 1~~3) placed on trails at latrine sites. 

Initially, the otter was immobilized in the trap with a hand injection of ketamine 

hydrochloride (11 mg/kg estimated body weight, Sigma, St. Louis, Missouri, 

USA) and then placed in a drugging box. The blood biomarkers measured in this 

study were not induced for at least 24 hours after exposure to an inducer, so if 

ketamine hydrochloride was an inducer, the effect would not be measurable in 

blood samples. Total body mass and length measurements were taken and a blood 

sample drawn from the jugular vein. Sexes were distinguished by the relative 

position of urogenital openings and palpitation of the baculum (Larsen, 1984). 

Age estimates of river otters using ageAength curves are inaccurate, so potential 

correlations between otter size and biomarker levels were controlled with the use 

of analysis of covariance. 
Figure I. Study area for pigeon guillemots in Kachemak Bay, Alaska, during the 1994 breeding 

season. All guillemot nests in the study were located along the south shore of Kachemak Bay 

from Seldovia to Bear Cove. 

Results and Discussion 

Guillemots 

Sixty-two active and accessible nests were found along the rocky shores of the 

south side of Kachemak Bay and on nearshore islets demonstrating that adequate 

numbers of accessible pigeon guillemot nests for the proposed 1995 dose-response 

experiment are present in Kachemak Bay. Most nests were located in crevices in 

vertical cliffs, presumably as a defense against nest predation by terrestrial mammals (e.g., mink), making access more time consuming than originally anticipated. Visual observation confirmed that marine fishes were by far the major food 

source of breeding pigeon guillemots in Kachemak Bay; guillemots were not 

observed to feed any invertebrates to their nestlings. Also, diet composition was 

different than that reported for other guillemot populations in the Pacific Northwest, where bennies and sculpins were a major part of the diet. In Kachemak Bay, 

46% of prey items delivered to the nestling were sand lance (Ammodytes sp.), 

while sculpins comprised only 2%, and gunnels/pricklebacks, 29% of nestling diet 

(Figure 2). This diet composition is similar to that of guillemots breeding at 

Naked Island in Prince William Sound prior to the Exxon Yadez oil spill. Nestling diet composition in Kachemak Bay varied among sites (Figure 3). Sand lance 
were much more prevalent and gunnels less prevalent at Moosehead Point (China 

Poot Bay) than at Halibut Cove or Kasitsna Bay to the east and west, respectively. 

a) Growth Rates. Growth rates in body mass of known-age chicks were 

measured and several other methods were used to incorporate data from 

chicks of unknown ages. Growth in mass is approximately linear fiom day 

8 to 18 in guillemots. This rate is easy to calculate and can be used for 

comparisons, but confidence intervals for growth rates are large (Figure 4). 

Growth rates can also be estimated for chicks of unknown age by weighing many chicks at a constant time interval (e.g., three days). By determining the increase in mass over this interval for various initial weights 

(Figure 5), the change in mass with age can be reconstructed. Using 

measurements taken three days apart provided a growth curve very similar 

to that produced by using only values from known-age chicks (Figure 6). 

The growth rate from day 8 to 18 was 17.3 g per day. 

b) Productivity. Average clutch size was 1.68 eggs/nest (n=38 nests). Productivity and other parameters of reproductive success were estimated using 

the Mayfield Method. Productivity (number of fledglings produced per 

nest where at least one egg was laid) was low at 0.41 fledglingdnest, due 

mainly to a high predation rate on eggs (50%) and low hatching success 

(76%, Figure 7). Of those chicks that hatched, 57-69% survived to fledgling. There was considerable variation among locations within Kachemak 

Bay in the causes of nest failure (Figure 8). Guillemots breeding at 

Moosehead Point and China Poot Bay experienced much higher egg 

losses (69%) than birds nesting to the east (30%) or west (36%). However, 

guillemot nestlings suffered lower mortality rates at Moosehead Point/ 

China Poot Bay (2% of nests) than to the east (12%) or west (13%). 

c) Biomarkers. Extensive blood samples and liver tissue samples were 

collected from nestling guillemots. Many of these analyses are currently 

underway. Total plasma protein as well as classes were determined over 

time. These data are summarized in Tables 2-4. Haptoglobin levels were 

also measured in a timed series. 

Haptoglobin levels varied significantly among nests but were not significantly different among ages, locations, dates, or between alpha and beta 

chicks. Overall serum protein levels were positively correlated with 

haptoglobin levels (R = 0.46) but did not vary among nests, locations, 

ages, dates, or alpha and beta chicks. The levels of haptoglobin and total 

proteins in serum were not correlated with growth performance (Figure 9) 

as indicated by the residuals of body mass as a function of wing length 

(Figure 10). The immune system was judged by IL-6 levels. All IL-6 

levels were below detection, giving a relative zero as a baseline for the 1995 

dosing experiment. 

The variation in individual birds over time was interesting. For example, 

the chick in Nest 2 had an HP level of 52 on July 18, and an HP level of 

99 on July 28, while the chick in Nest 43 had an HP level of 80 on August 

4, and 0 on August 11. 
River Otters 

Twenty active otter latrine sites were identified and scat samples collected for 

stable isotope analysis as well as metal and porphyrin analysis. Preliminary results 

indicated very low levels of total porphyrins in feces. Overall the baseline data 

collected in 1994 and the logistical experience gained in Kachemak Bay portend 

for a successful field season in 1995. River otter blood samples were not taken in 

1995, but several whole river otter carcasses (including livers) were obtained for 

laboratory analysis. 

Comparative Implications of Bioindicator Studies 

Guillemot growth data fiom the study in Kachemak Bay was compared to similar 

data from oiled and unoiled areas of Prince William Sound in 1994 (D.L. Hayes, 

unpublished data). It was found that Kachemak Bay guillemot nestlings had 

significantly lower growth rates and fledged at significantly lower body mass than 

guillemot nestlings raised on Jackpot Island in an unoiled area within Prince 

Wiam Sound. Growth rates and fledgling mass of guillemot chicks on Naked 

Island, in an oiled portion of Prince Wiam Sound, were indistinguishable from 

those of Kachemak Bay guillemot chicks (Figure 11). This supports the concept 

that monitoring growth of guillemot chicks provides a sensitive model for 

studying the local effects of environmental pollution and prey availability. 

Kachemak Bay is not considered part of the Exxon E'aldez Oil Spill Area, although shoreline at the mouth of the bay may have been lightly oiled. The 

differences in growth rate of guillemot nestlings between Kachemak Bay and 

Jackpot Island may be due to the differences in contaminant exposure andlor 

differences in the quantity or quality of forage fish. Studies designed to address 

these issues are being planned for 1995. 

Pigeon Guillemot Provisioning 

Kachernak Bay, Alaska 

1 other (2.27%)~ I 

2. Taxonomic composition of the diet for pigeon guillemot nestlings in Kachemak Bay, 

Alaska during the 1994 breeding season. Percentages represent the proportion of total observed 

prey items delivered by guillemot adults to nests containing chicks. The "othern category 

includes flatfish, greenling, and cod. 
Pigeon Guillemot Provisioning 

Kachemak Bay, Alaska 

Halibut cove 

flatiish (0.00%) 

sculDins 11.53%) 

Moosehead Pt. 

flatlish (0.00%) 

xulpins (3.85%) 

. . (23.08%) 

Gunnels (34.35%) 

Sandlance (38.93%) Sandlance (61.54%) 

N. Neptune to Seldovia 

Figure 3. Taxonomic composition of the diet for pigeon guillemot nestlings in three areas of 

Kachemak Bay, Alaska during 1994. Percentages represent the proportion of total observed 

prey items delivered by gdemot adults to nests containing chicks. 

Linear Phase of the Growth Curve 

Growth is approximately 

linear from day 8 to 18 in 

guillemots. This rate is easy 

to calculate and can be used 

for comparisons. It requires 

a large data set of known age 

chicks between these ages. 

With our data, the 95% 

confidence limits around the 

slope was too large for 

meaningful comparisons 

between populations 

(1 1.8-22.7 my). 

Figure 4. Nestling body mass as a function of age (days post-hatch) for pigeon guillemots in 

Kachemak Bay, Alaska during 1994. The figure depicts the "linear phase" of nestling growth in 

body mass, about 8-18 days post-hatch. The line represents the least squares regression for the 

entire data set. 
Guillemot Weight Gain 

Three dav intervals 

- 1 . '/.. ............................... 

O : 37 grams at day 1 

J1.4 

1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 

Log of Initial Weight (g) 

5. Nestling body mass as a function of body mass three days earlier (initial mass) for 

pigeon guillemots breeding in Kachemak Bay, Alaska, during 1994. The figure shows the 

three-day mass increment in relation to the "no-growth" line (lower dashed line). These graphs 

can be used to construct sigmoidal growth curves from data obtained from nestlings of 

unknown age. 

Growth Rate vs. Age 

500 - 

FGgure 6. Nestling body mass as a function of age for pigeon guillemots nesting in Kachemak 

Bay, Alaska, during 1994. Data points are from known-age nestlings, the thin solid line 

represents the age-specific means of body mass for known-age nestlings, and the heavy solid 

curve is from three-day mass increment data. 
Productivity of Pigeon Guillemots 

Kachemak Bay, Alaska 

Daily Survival 

Rate 

V" Pro~ortion of 

Chicks C1 chi& surviving 

Figure 7. Productivity of pigeon guillemot nests in Kachemak Bay, Alaska, during the 1994 

breeding season. The front set of bars indicates the proportion surviving after each phase of 

the breeding period. The back set of bars indicates the daily survival rate for each phase of the 

breeding period. 

Local Differences in Nest Failure 

Guillemots Breeding in Kachemak Bay 

Mallard Bay and Halibut Cove China Poot Bay and Moosehead Point 

Neptune Bay to Seldovia Bay 

mortality from day 4 to 

proportion survlvmg 

to day 30 post hatch 

hatching 

Figure 8. Causes of breeding failure for pigeon guillemots nesting at three locations within 

Kachemak Bay, Alaska, during 1994. 
Table 2. Guillemot a chick plasma proteins and HI? 

# Date Total P2 pl-2 pl 1x2 a1 Alb/pre HP 

Protein 

0.19 

0.1/0.21 

0.25 

0.49 

0.39 

2.44 

0.31 

0.17 

0.17 

0.34 

0.63 

0.38 

0.47 

0.53 

0.37 

0.57 

0.69 

0.56 

0.25 

0.50 

0.44 

0.45 

0.62 

0.79 

0.37 

0.61 

0.61 

0.11/0.29 

0.45 

0.28 

0.32 

0.53 

0.05/0.57 

0.18 

0.42 

Blank 

0.43 

0.48 

0.48 

0.45 

0.37 

0.46 

0.32 

0.40 

0.52 

0.39 

0.41 

0.43 

0.53 

0.25 

0.49 

0.26 

0.26 

0.51 

0.19 

0.16 

- 

0.14 

0.15 

0.04 

0.39 

0.32 

0.12 

0.24 

- 

- 

0.38 

0.50 

0.33 

0.54 

0.24 

0.34 

0.36 

0.44 

0.70 

0.28 

0.36 

- 

0.38 

0.44 

- 

00 

0.05 

0.26 

0.11 

0.21 

0.26 

0.20 

0.30 

lane 

0.23 

0.29 

0.18 

0.22 

0.15 

0.19 

0.25 

0.35 

0.22 

0.43 

0.20 

0.53 

0.17 

0.40 

0.32 

- 

0.44 

0.31 

0.18 

0.14 

- 

0.22 

0.11 

- 

- 

- 

- 

0.18 

0.17 

- 

0.34 

- 

- 

0.34 

- 

- 

- 

- 

- 

- 

- 

- 

- 

- 

00 

- 

- 

- 

0.16 

0.23 

0.34 

- 

needs 

- 

- 

- 

0.06 

0.08 

0.17 

- 

- 

0.11 

- 

- 

- 

- 

- 

- 

- 

0.52 

- 

- 

- 

- 

0.34 

0.29 

0.57 

- 

- 

0.48 

0.26 

0.48 

2.22 

- 

- 

- 

- 

0.24 

0.29 

- 

- 

0.16 

0.26 

0.55 

0.61 

0.37 

0.42 

- 

- 

0.46 

0.11 

0.55 

0.17 

0.41 

0.18 

0.33 

run 

0.58 

0.44 

0.48 

0.61 

0.40 

0.31 

0.69 

- 

0.56 

0.52 

0.65 

0.54 

- 

- 

- 

0.35 

- 

0.39 
Table 3. Guillemot P chick plasma proteins and HP. 

# Date Total Y P2 Pl-2 Pl a2 a1 Alb/pre HP 

Protein 

Table 4. Adult pdlemot plasma protein and HP. 

# Date Total Y P P P a a Alb/pre HP 

Protein 

24 7/21 2.85 0.50 0.24 0.68 - 0.03 1.40 197 

37 7/29 3.15 0.50 0.13 - 0.44 0.39 0.93 0.91 138 

41 7/27 3.70 0.33 0.59 - 0.73 0.65 0.42 0.99 177 

62 8/12 3.23 0.73 0.27 - 0.43 0.57 1.20 195 
Haptoglobin vs. Growth Performance 

gso0 - 7- - 

P E' - 

z250 - - 

(L1 

> 

3 200 - *- . c 

i- - 

-200 -150 -100 -50 0 50 100 150 

Residuals of Weight on Wing Length 

Figure 9. Levels of serum haptoglobins as a function of growth performance index in pigeon 

guillemot nestling from Kachemak Bay, Alaska, 1994. The growth performance index was the 

residual about the regression of total body mass vs. wing length (a surrogate for body size). 

Nestlings with high positive residuals were heavy for their body size, whiie nestlings with low 

negative residuals were underweight for their size. 

Weight as a function of wing length 

Pigeon Guillemots-Kachemak Bay 

600 / r 

0 20 40 60 80 100 120 140 160 

Wing Length (mm) 

Fig 10. Nestling body mass as a function of wing length in pigeon guillemots from Kachemak 

Bay, Alaska during 1994. Triangles indicate the quadratic model fitted to the data set. 
Jackpot Island and Kachemak Bay 

1 1 .I 1.2 1.3 1.4 1.5 

sqrt(log) wing length (mm) 

Fig 11. Nestling body mass as a function of wing length for pigeon guillemots from Kachemak 

Bay, compared with Jackpot Island in Prince Wiam Sound, Alaska, during 1994. Body mass 

was square root transformed and wing length was transformed by taking the square root of the 

log. These transformations linearized the relationship between body mass and wing length, 

and produced homogeneous variance about the linear regression. These conditions are 

essential for meeting the assumptions of linear regression and allow slopes of regression lines 

to be compared. The slope of the regression line for guillemots raised at Jackpot Island was 

greater than that of guillemots raised in Kachemak Bay. Jackpot Island is in a part of Prince 

Wiarn Sound that was not oiled during the hon Valdez oil spill. 

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Bowyer, R. T., J. W. Testa, J. B. Faro, C. C. Schwartz and J. B. Browning. 1995. 

Changes in diets of river otters in Prince William Sound, Alaska: Effects of 

the Exxon Vadez oil spill. Can. J. 2001.72: 970-976. 

Clark, J. D., J. H. Jenkins, P. B. Bush and E. B. Moser. 1981. Pollution trends in 

river otter of Georgia. Proc. Southeast Assoc. Fish Widl. Agencies 35: 71-79. 

Docktor, C. M., R. T. Bowyer and A. G. Clark 1987. Number of corpora leutea 

as related to age and distribution of river otters in Maine. J. Mammal. 

68: 182-185. 

Drent, R. H. 1965. Breeding biology of the pigeon guillemot, Cepphus columba. 

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the Exxon Valdez oil spill on blood and enzyme chemistry of river otters. 

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Cassin's auklets exposed to oil. Arch. Environ. Contarn. Toxicol. 14: 725-737. 

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environmental contaminants in river otters (Lutra lutra) of Georgia and their 

relationship to the possible decline of otters in North America. Proc. Worldwide Furbearer Conf. 3: 1752-1762. 

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Worldwide Furbearer Conf. 3: ~63-1780. 

Larsen, D. N. 1984. Feeding habits of river otters in coastal southeastern Alaska. 

J. Wildl. Manage. 48: 1446-1452. 

Leighton, F. A. 1985. Morphological lesions in red blood cells from herring gulls 

and Atlantic puffins ingesting Prudhoe Bay crude oil. Vet. Pathol. 22: 393- 

402. 

O'Connor, D. J. and S. W. Nielson. 1981. Environmental survey of methylmercury levels in wild mink (Mustela vison) and otter (Lutra canadensis) from the 

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methylmercurialism in the otter, p. 1728-1745. In J. A. Chapman and D. 

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Environ. Res. 27: 206-215. 

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Effects of ingested crude oil on black guillemots: A combined field and 

laboratory study. Ambio 9: 28-30. 

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marine river otter populations in Prince Wiam Sound, Alaska using radiotracer implants. J. Mammal. 75: 1021-1032. 

Woolington, J. D. 1984. Habitat use and movements of river otters at Kelp Bay, 

Baranof Island, Alaska. M.S. thesis, Univ. Alaska Fairbanks. 147 p. 

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A Study of the Adsorption and 

Biodegradation of Aromatic Hydrocarbons 

by Marine Sediments 

Susan M. Henrichs 

Michelle Luoma 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7220 

Abstract 

Sources of acute and chronic discharges ofpetroleum to the marine environment 

include marine transportation, municipal waste and run05 rejneries, and ofshore 

oilproduction. Aromatic constituents ofpetroleum are of special concern because 

their toxicities are greater than those of most other components. Because of their 

hydrophobicproperties, aromatic hydrocarbons have a strong tendency to become 

associated with particles in sediments, and this association could afect their biodegradation. The adsorption of a spec@ aromatic hydrocarbon, phenanthrene, by 

intertidalsediments ofJakolof Bay, Lower Cook Inlet, was studied. Phenanthrene is 

strongly adsorbed by these sediments, and the adsorption is not completely, rapidly 

reversible by suspension of the sediment in clean seawater. Of thephenanthrene 

which is adsorbed irreversibly, SO-90% can be extracted by methanol. Adsorption is 

a linear function of dissolvedphenanthrene concentration, and allsites for adsorption on the sediment surface appear to be equivalent. In collaboration with Joan 

Braddock, the efects of adsorption on the rate and extent of decomposition by 

bacteria are being studied. 

Introduction 

Overview 

The Alaskan Coastal Marine Institute (CMI) developed a group of "Framework 

Issues'' which describe the concerns to be addressed by CMI-supported research. 

Among these, there was a need identified for "experimental studies for better 

understanding of environmental processes or the causes and effects of outer 

continental shelf (OCS) activities" (University of Alaska CMI Annual Report 

No. I). Lower Cook Inlet is a site of offshore oil and gas production. Offshore 

production and marine transportation are sources of petroleum hydrocarbons to 

the ocean (National Research Council, 1985). Although aromatic hydrocarbons 

make up only a small part (approximately 10%) of the complex mixture of 

compounds in petroleum, they are of special concern because they are among the 

most toxic, mutagenic, and carcinogenic constituents (White, 1986; Pahlrnann 

and Pelkonen, 1987). Sediments are important reservoirs for polycyclic aromatic 
hydrocarbon (PAH) contamination in the marine environment (Wakeham and 

Farrington, 1980; Gschwend and Hites, 1981). Also, there is evidence that sediments are a major source of PAH and other hydrophobic pollutants to marine 

and lacustrine organisms (McElroy et al., 1989). Although sedimentary contamination decreases markedly with time after a spill, due to biodegradation and other 

processes, aromatic hydrocarbons can persist for at least 20 years in contaminated 

sediments (Teal et al., 1992). A factor in this persistence could be the strong 

association between sediment particles and aromatic hydrocarbons (Means et al., 

1980) and a possible decrease in biodegradability associated with this adsorption 

(Guerin and Boyd, 1992). 

Chronic discharges and small oil spills are a much larger source of petroleum 

contamination to the oceans, integrated globally, than are large spills (National 

Research Council, 1985). In any locality with human activity, chronic, low-level 

petroleum inputs are a virtual certainty, whereas a catastrophic spill is unlikely. 

Processes controlling the fate of a large oil spill in Lower Cook Inlet have already 

been investigated under the "Environmental Assessment of the Alaskan Continental Shelf" program, sponsored by the National Oceanographic and Atmospheric Association and the Minerals Management Service (Payne et al., 1984; 

Payne et al., 1989). Processes affecting smaller inputs of oil, and, in particular, the 

fate of lower-level contamination in sediments, have not been studied previously. 

The present research is an experimental study of phenanthrene adsorption by 

Jackolof Bay, Lower Cook Inlet sediments to determine how adsorption may 

affect the persistence and fate of an aromatic hydrocarbon in these sediments. 

Two ways in which aromatic hydrocarbons can be lost from contaminated 

sediments are desorption, if the sediment is exposed to less-contaminated seawater, or biodegradation. Therefore this study included the investigation of the 

desorption of phenanthrene fi-om sediments. In collaboration with Joan Braddock 

of the University of Alaska Fairbanks Institute of Arctic Biology, this project is 

also investigating how adsorption affects bacterial degradation rates. During the 

next year, the study will be extended to include two other aromatic hydrocarbons, 

benzene and naphthalene, and another sampling site, a salt marsh. When future 

results are combined with this year's findings, information will be available on 

how aromatic hydrocarbon structure affects adsorption, desorption, and biodegradation, and how sediment composition affects adsorption. 

Adsorption of Aromatic Hydrocarbons 

Aromatic hydrocarbons have low aqueous solubilities and a high affinity for 

surfaces in aquatic ecosystems. However, within the this compound class, both 

solubility and surface affinity vary. For example, the aqueous solubility (g/100 g 

solution at 298OK) is 0.18 for benzene, 0.053 for toluene, 0.0031 for naphthalene, 

and 1.1 x for phenanthrene (Shaw, 198ga,b). Adsorption coefficients (q, or 

the adsorbed concentration/dissolved concentration ratio) of aromatic hydrocar- 
bons on marine and lake sediments are negatively correlated with aqueous 

solubility (Means et al., 1982). Sediment or soil composition affects adsorption. Kp 

increases with increasing organic content (Means et al., 1980; Schwarzenbach and 

Westall, 1981). Sorption of various aromatic hydrocarbons was correlated positively with the nonpolar-to-polar functional group ratio (Garbarini and Lion, 

1986; Rutherford et al., 1992) and aromaticity (Gauthier et al., 1987). 

In studies of the interactions of hydrophobic pollutants with soils and sediments, 

desorption is often found to be slower than adsorption, biphasic (rate decreasing 

with time), and incomplete (Isaacson and Frink, 1984; Brusseau et al., 1991; 

Pavlostathis and Mathavan, 1992). Slow desorption would be expected to decrease 

mobility and biodegradation of aromatic hydrocarbons in sediments and their 

biodegradation. Also, partition coefficients sometimes decrease with decreasing 

particle concentration, an effect which may be due to the binding of hydrocarbons 

by dissolved or colloidal components of experimental systems (Voice and Weber, 

1985). 

Studies of the adsorption of crude oil by several types of Kasitsna Bay (Cook 

Inlet, Alaska) sediments were reported by Payne et al. (1984) and Payne et al. 

(1989). Their goals and experimental methods were vastly different from those in 

this study. The Payne et al. studies were designed to determine the effects of 

suspended particulate matter on the removal of oil from seawater, in situations 

where the amount of oil in the system was fairly large compared to the amounts 

of water and sediment, and oil was mostly contained in a separate phase (surface 

slick). Payne et al. (1984) also investigated weathering and biodegradation of oil in 

severely oiled intertidal sites (1 liter oil/m2), where most of the petroleum was 

present in a separate phase or coating throughout the study. However, they did 

not address the effects of adsorption on the fate of petroleum in slightly- to 

moderately-contaminated sediments, which is defined in this study as those 

containing 5 100 pg petroleum hydrocarbons per gram of sediment. 

Adsorption Effects on Bioavailability 

Although there have been many previous studies of the microbial decomposition 

of hydrocarbons in the environment (reviewed by Leahy and Colwell, ~ggo), "the 

influence of sorption on the biodegradation of NOCs [nonpolar organic compounds] has been the subject of much speculation but little definitive experimentation. Sorption is generally thought to limit the availability of organic 

compounds, although the few published studies in this area ... arrived at alternate 

conclusions regarding whether or not sorbed compounds are available to microbial degraders" (Guerin and Boyd, 1992). 

Several variables have been identified as affecting adsorption or its influence on 

decomposition rate or extent. Miheicic and Luthy (1991) found that naphthalene 

degradation rates were decreased by adsorption, and Manilal and Alexander 

(1991) found that adsorption slowed phenanthrene decomposition, but Fu and 
Alexander (1992) found that styrene adsorbed to soils decomposed rapidly. 

Guerin and Boyd (1992) found that two bacterial species had very different 

abilities to degrade naphthalene adsorbed to soils. Weisenfels et al. (1992) concluded that biodegradability and biotoxicity of PAH were decreased by adsorption and migration into an organic matter matrix. Adsorption effects on 

decomposition are difficult to quantifjr, since the chemical properties of the 

sorbate, sorbent, and aqueous solution, the mechanism of sorption, the time 

allowed for equilibration, and the characteristics of the organisms present all can 

influence biodegradation (Guerin and Boyd, 1992). 

There is also no definitive answer to the question ofwhether adsorption to 

sediments affects hydrocarbon availability to higher benthic organisms. Sediments are apparently a major source of PAH and other hydrophobic pollutants to 

benthic invertebrates (McElroy et al., 1989). The evidence includes correlations 

between the concentrations and compositions of PAH in the organisms and their 

associated sediments. Also, it has been shown that feeding strategy affects hydrocarbon content and composition of invertebrates from a single site, indicating 

that a likely route of contamination is the digestive tract. 

Summary 

Aromatic hydrocarbons are strongly adsorbed by marine sediments, and adsorption is not rapidly, completely reversible, indicating that this process probably 

affects PAH retention by contaminated sediments. Organic matter appears to be 

the main adsorbent, but clay minerals could have a significant role in organicpoor sediments. The effects of adsorption on aromatic hydrocarbon biodegradation are not well understood and probably vary with the compound properties, 

bacterial community, and sediment composition. Results of most experiments 

indicate that adsorption decreases bioavailability and may contribute to the 

persistence of aromatic hydrocarbons in sediments. 

Methods 

Sediments used in this study were collected in July 1994 from the northeastern 

shore, near the mouth of Jakolof Bay, which is located along the southwestern 

margin of Kachemak Bay in Lower Cook Inlet. These sediments were also used 

in studies of microbial degradation of phenanthrene reported by Joan Braddock 

Sediments were collected from the oxic, upper 1 cm layer. The sediments primarily consisted of silt. The samples were stored under refiigeration until used in the 

experiments. 

Adsorption was measured using 9-14C-phenanthrene (5-15 mCi/mmole) obtained fiom Sigma Chemical Company. The solutions were prepared with 

approximately 0.002 Kurie/mL (or 0.1 nmole/mL) of radiolabeled phenanthrene plus sufficient nonradioactive phenanthrene (also purchased from Sigma) 
to obtain the desired concentration. The radiolabeled compound purity was 

initially checked by thin-layer chromatography, which revealed no indications of 

impurities. However, recent analyses by a higher-resolution high pressure liquid 

chromatography (HPLC) method indicate that approximately 25% of the 

radiolabel, as received from the supplier, is not phenanthrene. Based on its 

chromatographic properties, the contaminant is probably another aromatic 

hydrocarbon. The data for this contaminant will be corrected once all HPLC 

analyses are complete. The values reported here are not corrected; however, 

because the contaminant and phenanthrene appear to have similar properties, a 

large change in the final results is not anticipated. 

Formaldehyde (2%) was found to be effective in preventing respiration (as measured by evolution of 14C02) of phenanthrene in non-sterile seawater solutions 

and sediments. It was used to prevent biological uptake of phenanthrene in all of 

the experiments described here. 

Adsorption experiments involved suspending 0.05 g of wet sediment in 5 mL of 

phenanthrene solution in filtered seawater. The seawater was collected from 70 m 

depth in Resurrection Bay, Seward, Alaska. This water was used because it is 

more uniform in its properties than Kasitsna Bay water. Reaction times varied 

fiom 15 minutes to three days. Sediment was removed by centrifugation and 

filtration through a Whatman GF/F filter, then the activity remaining in solution 

was measured by liquid scintillation counting. For some experiments, adsorbed 

phenanthrene was then desorbed by suspending the sediment in phenanthrenefiee seawater. Some sediments were also extracted with solvents in order to 

recover adsorbed phenanthrene. 

Results and Discussion 

Adsorption of Phenanthrene by Jakolof Bay Sediments 

Adsorption coefficients have been measured at a total of eight concentrations, 

using three different reaction times at four of the concentrations and a single, 

one-day reaction time at the other four concentrations (Table I). The adsorption 

coefficients (>400 mL/g dry sediment at the one-day reaction time) were large at 

all concentrations tested, showing a strong adsorption of phenanthrene by the 

sediment particles. As indicated in Table I, experiments at four of the concentrations used homogenized sediment fiom a single subsample jar. When this was 

exhausted, another jar of sediment was homogenized and used for the subsequent 

four experiments. The adsorption coefficients for the two groups of experiments 

are significantly different, although they agree within a factor of two. We attribute 

this difference to variations in sediment properties, although the samples were 

collected within a few meters of each other. 
Table I. Adsorption of phenanthrene by Jakolof Bay sediments. 

Sediment Subsample Number 1 

 con^.^ Reaction Partition % of Adsorbed % of Adsorbed 

(Pgm Time (da s) Coefficient Extracted by Extracted 

(m LIE) T SeawateP bv Methanolb 

Sediment Subsample Number 2 

 con^.^ Reaction Partition % of Adsorbed % of Adsorbed 

(pg/L) Time (da s) T Coefficient Extracted by Extracted 

(mL/!z) SeawateP bv Methanolb 

44 1 850 (130) 11 (1) 44 (0.4) 

200 1 1200 (440) 13 (1) 43 (2) 

300 1 680 (140) 10 (2) 42 (5) 

600 1 720 (170) 16 (1) 48 (3) 

'Phenanthrene concentration in the seawater solution before adsorption. 

bValues shown are the mean of three replicates, except that one replicate was lost (750 pg/L, 0.083 day) and one replicate 

was disregarded (300 pg/L, 1 day) because it differed by more than three standard deviations from the mean of the other 

two. Standard deviation is given in parentheses. 

The strong adsorption of phenanthrene indicates that in these intertidal sediments, nearly all of any contaminant phenanthrene should be adsorbed, provided 

that petroleum contamination levels are not so high that substantial oil exists as a 

separate phase. For example, for a typical sediment consisting of about 70% water 

and 30% particles by weight, the adsorbed inventory would be 300 times the 

dissolved inventory. This, in turn, would mean that loss by desorption and 

dfision to overlying water (even for reversibly-sorbed phenanthrene) would 

be slow. For example, if the upper 2 cm of a sediment were contaminated with 

1 pg/g of phenanthrene, it would require about three years for this contaminant 

to be desorbed and lost to overlying water, if no biodegradation occurred. 
The strong adsorption may also contribute to the processes leading to contamination of sediments. The research described here most directly addresses the 

situation where a thin (less than 1 mm thick) surface slick or other floating oil is 

grounded on the intertidal zone by a high tide, wind, andlor waves. If the oil is 

fairly "fi-esh," it will leach aromatic hydrocarbons into any overlying water and 

porewaters of underlying sediments. The strong adsorption of aromatic hydrocarbons by sediments will result in their contamination. Depending on how rapidly 

the adsorbed hydrocarbons are biodegraded (the subject of the research collaboration with Braddock), the adsorbed hydrocarbons may persist even after the 

floating oil is removed by physical processes, degraded photochemically, etc. In 

contaminated waters, particles would also acquire substantial concentrations of 

phenanthrene by adsorption, and this could affect concentrations in bottom or 

intertidal sediments. For example, if water phenanthrene concentrations were 

1 to 6 pg/L, which was the concentration range for PAH observed after the 

Exxon Valdez spill (Wolfe et al., 1995), predicted sediment concentrations are 

0.6-4 pg/g, well in excess of "baselinen concentrations in marine sediments 

(Wakeham and Farrington, 1980). 

There is no consistent pattern of change in the phenanthrene adsorption coefficient with concentration, i.e., adsorption is a linear hnction of dissolved concentration. This pattern indicates that all adsorption sites occupied are equivalent; 

that is, none tended to bind phenanthrene more strongly than others. There is 

also no evidence of saturation of adsorption sites over the concentration range 

tested, which was limited by the solubility of phenanthrene in seawater. 

Much of the adsorption occurred rapidly, within two hours (Table I). In fact, an 

earlier set of experiments (data not shown) found the same adsorption at reaction 

times of 15 minutes and two hours. However, adsorption after one day was 

approximately 50% greater than that at two hours. Adsorption after three days 

was not significantly greater than that at one day in one experiment (data not 

shown), but was slightly greater in a second experiment (Table I). Similar results 

for adsorption of hydrophobic organic chemicals by soils and sediments have 

been interpreted as due to rapid adsorption to sediment surfaces, followed by 

slower diision into sediment organic matter (Brusseau et al., 1991) 

Three different sediment:solution ratios for the reaction mixtures were tested at 

each concentration (Figure I). Although the mean partition coefficient was 

consistently lower for the largest sediment:solution ratio, there was no statistically 

significant difference in the partition coefficients. If partition coefficients are 

invariant with sediment:solution ratio, it is less likely that adsorption to colloids 

or complexation to dissolved organic matter are having a large effect on the 

behavior of phenanthrene. 
Phenanthrene 

concentration 

SedimentMlater Weight Ratio 

Figure I. Effect of sediment concentration on phenanthrene adsorption. 

Reversibility of Adsorption 

Experiments measured the amount of adsorbed phenanthrene that could be 

recovered by repeated 15-minute phenanthrene-fiee seawater extractions, essentially the reversibility of phenanthrene adsorption (Figure 2). The reversibility of 

phenanthrene adsorption was the same at the two concentrations tested, 10 and 

750 pg/L, so the data are pooled in Figure 2. A maximum of about 45% of 

adsorbed phenanthrene was desorbed by three seawater rinses. Approximately 

80% recovery would be expected if the adsorption were entirely reversible, i.e., the 

apparent partition coefficient for desorption was the same as that for adsorption. 

Recovery of adsorbed phenanthrene decreased for longer adsorption reaction 

times. Another experiment found that 10-20% of adsorbed phenanthrene could 

be desorbed by a single extraction with seawater for reaction times of two hours 

to three days, similar to the amount recovered in only 15 minutes (Table I). The 

reversibility of phenanthrene adsorption decreased with increasing reaction time. 

The low amounts of phenanthrene recovered by seawater could be explained if 

both very strong and weaker adsorption sites were present on the particle surfaces. However, this would also be expected to result in increased adsorption with 

decreasing concentration of phenanthrene in solution, which was not observed 

(Table I). The results are better explained by slow diffusion of phenanthrene into 

sediment organic matter (Brusseau et al., 1991); the reversal of that process would 

also be slow. The slow desorption means that contaminated sediments could be 

expected to retain substantial phenanthrene even if subsequently covered with or 

resuspended in clean seawater, at least on a time scale of days. In future work, 

longer times will be investigated. 
0 0.01 04 1 3 

Reaction Times (days) 

Figure z. Reversibility of phenanthrene adsorption by extraction of sediment with phenanthrene-free seawater. The reaction time given is for the adsorption of phenanthrene to the 

sediment. Each sediment sample was extracted three times. The first bar shows the recovery 

expected if the phenanthrene adsorption were completely reversible. 

Extractability of Adsorbed Phenanthrene 

Most of the adsorbed phenanthrene remaining after a seawater rinse could be 

extracted with methanol (Table I). Total recovery of adsorbed phenanthrene was 

nearly 100% at a low concentration, but approximately 70 to 80% at a higher 

concentration for the first set of experiments using one, homogenized sediment 

subsample. Total recoveries were much lower, 50 to 60% for the series of experiments done with the second sediment subsample. Acetone, acetonitrile, chloroform, 50:50 chloroform:methanol, methylene chloride, and toluene were also 

checked for their ability to extract adsorbed phenanthrene; none of these was 

more effective than methanol. All extractions were carried out over a relatively 

short time (0.5 hour). Incomplete solvent extraction could also be related to 

intraorganic matter diffusion; therefore longer extraction times will be investigated. One of the major objectives in investigating extractabiity of adsorbed 

hydrocarbons is to develop a method of recovering (and thus quantifying) 

adsorbed phenanthrene in biodegradation studies being conducted with 

Braddock 

Biodegradation of Adsorbed Phenanthrene 

As described in her report, Braddock has found that phenanthrene-degrading 

bacteria are present in the Jakolof Bay sediments studied. Because she began her 

work several months after this study began, investigation of adsorption effects on 

biodegradation are still in progress. However, the strong adsorption of phenan- 
threne by Jakolof Bay sediments indicates that, if adsorption affects microbial 

decomposition rates, this process will have a significant effect on the biodegradation of this aromatic hydrocarbon. 

Preliminary Conclusions 

Phenanthrene is strongly adsorbed by Jakolof Bay intertidal sediments, and much 

of the adsorption is rapid, occurring within minutes. However, adsorption is not 

rapidly reversible, requiring more than several days in phenanthrene-fi-ee water. 

Of the adsorbed phenanthrene which is not desorbed in seawater, 50 to 90% can 

be extracted with methanol. Adsorption increases about 50% for reaction times of 

one to three days and becomes less reversible. Phenanthrene adsorption is approximately linear with concentration, indicating that all surface adsorption sites 

are approximately equivalent, but the adsorption coefficient varies by a factor of 

about two among sediment subsamples collected in a small area. Taken together, 

the characteristics of phenanthrene adsorption by the Jakolof Bay sediment are 

consistent with a process of rapid adsorption to the particle surfaces followed by 

slow diffusion into sediment organic matter. The strong adsorption indicates that 

this process could be an important factor in the acquisition and persistence of 

phenanthrene contamination in these sediments. The findings most directly 

address the situation where a thin surface slick or other floating oil is grounded 

on the intertidal zone and leaches aromatic hydrocarbons into the porewaters of 

underlying sediments. The strong adsorption of aromatic hydrocarbons by 

sediments will then result in their contamination. 

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28: 561-568. 
Kachemak Bay Experimental and 

Monitoring Studies 

Raymond C. Highsmith 

Susan M. Saupe 

Tama L. Rucker 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7220 

Abstract 

Several dzfering intertidal research eforts occurred along the oil impacted shorelines 

following the Exxon Yaldez oil spill. The lack ofpre-spill baseline data made these 

sampling eforts both time consuming and cost intensive. The CMI-Jirnded studies 

in lower Kachemak Bay were designed to obtain basic data on abundances and 

distributions of intertidal invertebrates and algae and to gather information 

throughout the year on community structuring mechanisms, such as recruitment and 

succession. The obectives were to gain an understanding of the relationships between and among intertidal invertebrates andplants, and some of the physical and 

environmental factors which drive these systems on exposed and sheltered rocky 

shorelines. In addition, it has been possible to compare several data collection 

methods commonly used during environmental impact studies of intertidalpopulations. Preliminary comparisons show signgcant dzferences between collection 

methods for many common invertebrates. 

Introduction 

Marine intertidal communities were the largest habitat category affected by the 

Exxon Yaldez oil spill, with damage from the oil and resultant cleanup activities 

occurring throughout the oil impacted area. The Coastal Habitat Injury Assessment (CHIA) study was initiated in 1989 to assess the injury to biological resources in intertidal habitats on oiled shorelines. That study encompassed the 

three major geographic areas impacted by the spill: Prince Wiam Sound, Cook 

Inlet-Kenai Peninsula, and Kodiak-Alaska Peninsula. Due to the lack of any 

baseline data, oiled sites were randomly selected and matched with non-oiled 

reference sites for an After Control-Impact Pair study design. There are several 

drawbacks to this design. The number of site pairs must be high enough and 

randomly selected in order to extrapolate study results to the rest of the oiled 

shorelines. There may also be inherent differences between oiled and non-oiled 

shorelines. For instance, the currents which carried the oil to certain shorelines 

may carry recruits and food to these same shorelines in greater abundance than to 

non-oiled shorelines, or areas which are "shadowed" by other areas of the coast- 
line. Shorelines near regions of active oil exploration and transport, such as 

Lower Cook Inlet, have the potential to be further impacted by oil and recovery 

activities in the event of another oil spill. 

Several interesting results were revealed during the CHIA study, although no 

firm conclusions could be made as to their causes or long-term stability. The 

barnacle Chthamalus dalli was found in higher densities on oiled sites compared 

with control sites, especially in the mid- to lower-intertidal zones (Highsmith et 

al., 1994). In undisturbed systems, C. dalli tends to be restricted to the high 

intertidal, due to competitive exclusion from lower levels by the superior space 

competitors, Balanus glandula and Semibalanus balanoides (Connell, 1961, Wethy, 

1985). C. dalli was the first species of barnacle to recruit into the free space created 

by the oil spill and cleanup activities. Settlement of C. dalli spat coincided with 

the availability of space resulting from the cleanup during the summer of 1989, 

giving this species a six-month advantage over the other prominent intertidal 

barnacles. Thus, the timing of the disturbance favored initial recruitment of one 

species over others. Mussel size and age data for sites sampled during the CHIA 

study (Highsmith et al., 1~~2) indicated that mussels of a given age tended to be 

larger on oiled sites relative to control sites. It was speculated that there may be 

inherent differences between oiled and control sites, and that the currents which 

delivered oil to certain shorelines may also concentrate recruits and fiesh particulates in the intertidal zone in these areas. 

The two main studies initiated for this CMI study in outer Kachemak Bay were 

designed to obtain "pre-spill* data on invertebrate and algal percent cover, abundance, recruitment, succession, and interactions. The major focus of the study has 

been to look specifically at recruitment and successional patterns in comparison 

with several physical factors, such as relative water motion and wave exposure. In 

addition, rates of recruitment and successional patterns are being studied on 

shorelines where disturbances (removal of all invertebrates and algae) occurred at 

different times throughout the year. These disturbances (cleared areas) were 

created at three different tidal elevations on each site, with sites chosen based on 

varying wave and current exposure. The clearings occurred in March, July, and 

October of 1994, and in March of 1995. They will be monitored over time to 

determine the recruitment of invertebrates and algae and to obtain data on the 

natural variabilities within undisturbed (non-cleared) communities. Information 

on intertidal communities for much of the Alaskan shoreline is sparse. The data 

collected in the CMI study will allow for a better understanding of the biological 

and physical processes that occur within intertidal communities and the potential 

effects of the nearby oil industry. 

Data collections for the recruitment and succession study also' allowed us to 

compare several methods commonly used for intertidal monitoring (Hawkins and 

Hartnoll, 1983; Foster et al., 1991; Hiscock, 1985)~ some of which were used for the 

Exxon Valdez oil spill studies (Highsmith et al., 1994; Gilfillan et al., 1993). These 
include point-contact methods for invertebrate and algal percent cover data 

collections, direct counts of invertebrates in the field, and collection of invertebrates with subsequent sorting and counting in the laboratory. In addition, for 

several organisms, two methods of counting were used in the field: total counts 

within a quadrat frame and random subsamples within the quadrat frame. The 

initial analyses of these data indicate that the accuracy of some methods is low, 

with many species being undercounted or completely missed in the field. The 

results of these method comparisons will be extremely useful for future development of damage assessment studies and intertidal community monitoring. 

Methods, Results, and Discussion 

Two major studies have been conducted since March 1994. The first, a recruitment/succession study, was conducted on eight sites. The sites were chosen to 

represent a gradient of wave exposures in order to improve our understanding of 

the relationship between recruitment and post-recruitment events to wave and 

current exposure. Dissolution rates of calcium sulfate were measured on each site 

to determine relative water motion (Muus, 1968, Gerard, 1982, Petticrew and 

Kalff, 1991). This was accomplished by deploying molded cylinders of gypsum at 

the 2.5 meter of vertical drop (MVD) from the mean high high water (MHHW) 

line on each site for three days. The amount of dissolved calcium sulfate was 

determined by the weight difference before and after deployment. The sites used 

for these studies were subjectively selected to represent a range of wave and storm 

exposure on rocky shorelines. Dissolution measurements are also sensitive to 

water motion independent of wave action, such as tidal currents. When the sites 

are ordered in a graph by subjective rankings of wave exposure, based on fetch, 

aspect, slope and grain size, the dissolution rates of the molded calcium sulfate 

cylinders generally follow a trend of higher dissolution on more highly exposed 

sites (Figure I). However, several sites have higher relative dissolution rates than 

expected based on wave exposure. At these sites, such as Jakolof Bay, there is 

usually a strong current due to tidal exchange through a constricted opening. 

On the sites selected for the recruitment/succession study, a "disturbance" was 

created by removing all organisms from quadrats at each of three MVDs along 

four transects on each site. A set of clearings was made on each site in March, 

July, and October 1994 and in March 1995. During subsequent visits to each set of 

clearings, percent cover estimates and direct counts were made of invertebrates 

and algae that had recruited into each cleared area. In addition, similar data were 

collected from permanently established control quadrats in order to obtain data 

on inter- and intra-annual variability. 

Data were obtained from the permanent control quadrats during the initial visit. 

The following invertebrates were counted from within each quadrat: the limpets 

Lottiapelfa, Tecturapersona, T scutum, L. borealis, L. di@talis, and unidentifiable 

limpets (juveniles); the barnacles Chthamalus dalli, Sernibalanus balanoides and 
AUGUST 1 994 

Wave exposure decreased 

Figure I. Mean dissolution (mg) of calcium sulfate cylinders deployed at the 2.5 MVD on 

recruitment~succession study sites over a three day period in August 1994. Sites are ordered 

from left to right in order of decreasing wave exposure. Four cylinders were deployed on each 

site. Vertical bars are one standard error. 

Balanus glandula (combined), Semibalanus cariosus, and unidentifiable barnacles 

(juveniles); the littorines Littorina sitkana and L. scutulata; the mussel Mytilus 

trossulus; the dog whelks NuceZZa lima and N. lamellosa; and the chiton Katharina 

tunicata. A 40 point grid was used to obtain percent cover estimates. What 

occurred immediately under each grid intersection was recorded, including algae, 

bare rock, or any invertebrates. During July, invertebrate count and percent cover 

data were collected fiom both the control quadrats and the quadrats scraped in 

March. During a low-tide series in October, direct counts were made of all 

invertebrates except barnacles on the March scrapes and of all invertebrates 

including barnacles for the July scrapes. In addition, percent cover data were 

collected for all organisms fiom the controls, and the March and July scrapes. 

The results of percent cover estimates of recruitment into scraped quadrats are 

summarized in Figures 2 and 3. One figure represents data from the same 

quadrats censused twice and the other figure presents data from two separate sets 

of quadrats each censused three months after initial clearing of the quadrats. 
Figure 2. The percent cover of recruited algae and inveiteljrates into quadrats that were 

scraped in March 1994. Recruitment was censused in July and October 1994. MVD = meter 

vertical drop. 

Figure 2 shows data from quadrats scraped in March 1994 and censused in July 

(columns labeled "Jul") and censused again in October (columns labelled "Oct"). 

Initial analyses show high numbers of barnacle recruits (mainly SemibaIanus 

balanoides and Balanus glandula at MVDs 1.5 and 2.5 and Semibalanus cariosus at 

MVD 3.5) on almost all sites following scraping in March 1994. Some die-off of 

barnacles had occurred between July and October, although total percent cover 

was still >SO% on most sites. Barnacles accounted for almost 100% of initial 

recruitment in the high- and mid-intertidal zones, especially at MVD 1.5. At 

lower MVDs, "other" organisms accounted for a larger percent of total cover. The 

"other" species included littorine snails, small limpets, and species of filamentous 

algae, such as Pilayella, AcrosiphoniaJ and Cladophora. These algal species were also 

initial recruits at sites damaged during the Exxon Valdez oil spill (Highsmith et 
- - - ((I - * 5 - 0 % 

Q) .- c C 

Y c .- n% c .- P, 

c 0 

C L 3 .- 

L Y % 8 Z 7 ((I 

? 

Y 

I - Q) 

I s 

z 

I 

2 

Figure 3. The percent cover of recruited algae and invertebrates into quadrats that were 

scraped in March and July 1994. The histograms labelled "Marn represent recruitment data 

obtained three months after scraping the quadrats in March. The quadrats labelled "Jul" 

represent recruitment data obtained three months after scraping the quadrats in July. MVD = 

meter vertical drop. 

al, 1994). For quadrats scraped in July 1994 and censused three months later in 

October, recruitment was very low (columns labelled "Jul" in Figure 3). The 

column labelled "Marn shows the data discussed earlier for quadrats scraped in 

March and censused in July, for direct comparison of recruitment after disturbances at different times of the year. The recruitment data in Figure 3 represents 

three months of recruitment time for each set of scrapes. Clearly, there is a large 

seasonal component in post-disturbance recruitment. The first field season data 

collections fi-om this study show weak or no correlation of initial recruitment into 
cleared quadrats (Figures 2 and 3) with gypsum cylinder dissolution rates measured at each site (Figure I). However, there are large differences in recruitment 

into cleared quadrats depending upon when the clearings were made. With 

continued monitoring in 1995 and 1996, the effects ofwave exposure, current 

regime, and seasonal timing of a disturbance on long-term recruitment, survival, 

and succession can be more thoroughly evaluated. 

Water currents are considered critical to the transport of recruited mussels from 

filamentous algae into adult mussel beds (Verwey, 1952). Eyster and Pechenik 

(15187) reported in a laboratory study that water agitation greatly enhanced larval 

attachment to filamentous substrata. Therefore, water motion appears to be an 

essential factor in both primary and secondary phases of recruitment for young 

mussels. A study was established in lower Kachemak Bay to compare the sizefrequency distributions of mussel populations during the spring and fall on eight 

sites with varying wave and current exposure. Along each of four randomly 

selected aansects, a quadrat was placed at the 1.8 and 2.3 MVDs for mussel 

collections. The quadrats were 10x20 cm and usually enclosed several hundred to 

several thousand mussels. All the mussels within each quadrat were collected and 

bagged, and then frozen and returned to the laboratory in Fairbanks for analyses. 

In the laboratory, the mussels were thawed and washed over a 0.5 mm sieve. The 

mussels were measured from the tip of the umbo to the widest portion of the 

posterior shell. Using dial calipers, measurements were taken to the nearest 

0.05 mm. Collections were made in March and October 1994. The laboratory 

analyses are completed for the March collection. The data from the October 1994 

collections are currently being entered and analyzed. 

Calcium sulfate dissolution rates for the eight mussel study sites generally agree 

with the wave exposure rankings (Figure 4). Mussel data collected from the sites 

were plotted on cumulative frequency curves to illustrate differences in population 

size-frequency distributions between sites (Figure 5). Straight cumulative frequency curves, with a y-intercept near zero, represent populations with evenly 

distributed mussel sizes. Curves with a steep slope at small sizes and a large yintercept, represent populations with a high percentage of small individuals. Also, 

curves that approach a frequency of 1.0 at small size categories represent populations with very few large mussels. For the cumulative frequency curves in Figure 

5, the order of the symbols in the legend, from top to bottom, represent the sites 

ordered from left to right in Figure 4. The size-frequency curves for the three 

sites with the highest percentage of large mussels (Little Jakolof, Cronin I, and 

Little Tutka) are the sites with the lowest wave exposure rankings. Two of the 

three sites also have the lowest gypsum dissolution rates, or relative water motion. 

Perhaps at the sites with higher wave exposures, mussels are exposed to forces 

sufKcient to rip byssus threads from the substrate. Large mussels have larger 

surface areas and protrude from the substrate more than small mussels, thus 

increasing drag forces. Therefore, sites with higher wave exposure may have a 

smaller percentage of large mussels. Mussel larvae generally recruit onto filamen- 
tous algae (Bayne, 1964; Seed, 1976). However, other investigators have observed 

small, (1.0 mm mussels within the byssus mat of adult mussel beds (Petersen, 

1984; McGrath et al., 1988). The high numbers of very small mussels (<1.0 mm) 

on many sites suggest that larvae may have recruited directly into the adult beds. 

In addition, the presence of the (1.0 mm mussels in April indicate that a settlement occurred at some point in the winter of 1993/1994. Mussels may undergo 

more than one annual spawning event when environmental conditions permit 

(Seed, 1976; Lower et al., 1982), although in Alaskan waters the major settlement 

pulse occurs in late July to early August (Ralonde, pers. comm.). The samples 

collected in fall 1994 will allow us to determine if there are differences in mussel 

recruitment among the sites due to wave exposure or water current rates. 

During the recruitment/succession study described previously, four sites were also 

"double-sampled." Before destructive sampling on the sites, we had an opportunity to take individual counts and percent cover data of specific invertebrates 

from those quadrats that were to be scraped and burned for monitoring of hture 

recruitment and succession. During the scraping procedures, all invertebrates 

within each quadrat were collected and preserved. In the laboratory they were 

rinsed over a 1.0 mm sieve, sorted to the lowest possible taxonomic level, and 

counted. The personnel conducting the field and laboratory counts have been 

identifj.ing Alaskan intertidal invertebrates since the oil spill in 1989 and are 

9 JULY 1994 

Figure 4. Mean dissolution (mg) of calcium sulfate cylinders deployed at the 2.0 MVD on 

mussel study sites over a three-day period in July 1994. Sites are ordered from left to right in 

order of decreasing wave exposure. Four cylinders were deployed on each site. Vertical bars are 

one standard error. 
0.0 I I I I I I I I I I 1 

4 8 12 16 20 24 28 32 36 40 

Size Category (mm) 

Figure 5. Cumulative frequency curves for mussel populations on the eight mussel study sites. 

The curves illustrate the contribution of each successive size class to the population. The order 

of the symbols in the legend, from top to bottom, correlate to the sites ordered from left to 

right in Figure 4. MB1 = Hesketh I, MB2 = Hesketh 11, MB3 = Yukon Isl., MB4 = Cronin I, 

MB5 = Little Jakolof, MB6 = Herring I, MB7 = Little Tutka, MB8 = Nubble Point. 

highly experienced taxonomists. The samples are currently being sorted in the 

laboratory and the results are not complete. However, for those quadrats that 

have been analyzed, the field counts underestimate the number of organisms 

actually present. For example, the blue mussel Mytilus trossulus was undercounted 

by up to a factor of four. Mussels ofien grow in layers. Small mussels completely 

hidden by larger mussels above are missed during field counts. Other organisms, 

such as small limpets, hide inside large barnacle tests, Semibalanus cariosis, for 

example, and are undetectable during field counts. Barnacles often grow in 

"hummocks" where many barnacles are crowded together and it is difficult or 

impossible to identify individual barnacles. With the additional opportunistic 

field collections mentioned above, it will be easier to interpret data collected by 

either method and judge the benefits and drawbacks of each method. For instance, the nondestructive method of counting organisms directly on-site is much 

more cost effective as no additional laboratory procedures are necessary. However, 

abundances of many organisms may be underestimated in the field. Percent cover 

estimates miss many small or mobile species and the method is best for counting 

primary space competitors such as barnacles, mussels, and algae. Possibly, the 

ideal method for monitoring intemdal communities is a combination of all three 

methods. 
Preliminary Conclusions 

The preliminary data shows that water motion may have an effect on recruitment 

and succession of intertidal invertebrates, especially for the blue mussel, Mytilus 

trossulus. Initial recruitment of barnacles was high on all sites after the quadrats 

were scraped in spring of 1994. However, after the quadrats were scraped in July, 

recruitment by fall was very low, ofien with zero percent cover in the quadrats. If 

early algal recolonization occurs in spring 1995, the bare space might not be 

available for barnacle recruitment to the extent seen for those quadrats scraped in 

spring 1994, possibly resulting in differing successional patterns. If the quadrats 

scraped in July remain bare, barnacles may be the main initial recolonizers in 

spring and summer. This would, in effect, have delayed the "recovery" of the 

cleared quadrats by nine months compared to the quadrats cleared in March. 

However, successional patterns may be similar in the long term. 

The data collected during the "double-sampling" study strongly suggests that the 

method used for invertebrate monitoring may afEect the results obtained. Field 

counts underestimate the abundance of many invertebrates, percent cover estimates using the point-contact method miss many smd and mobile species, and 

laboratory counts, though more accurate, are time consuming and costly. The 

data collected during this CMI-funded study will be invaluable for judging the 

benefits and drawbacks of each method when designing future monitoring 

studies, both pre- and post-disturbance. 

References 

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Anim. Ecol. 33: 513-523. 

Connell, J. H. 1961. The influence of interspecific competition and other 

factors on natural populations of the barnacle Chthumalus stellatw. Ecology 

42: 710-723. 

Eyster, L. S. and J. A. Pechenik 1987. Attachment of Mytih edulis L. larvae on 

algal and byssal filaments is enhanced by water agitation. J. Exp. Mar. Biol. 

Ecol. 114: 99-110. 

Foster, M. S., C. Harrold and D. D. Hardin. 1991. Point vs. photo quadrat 

estimates of the cover of sessile marine organisms. J. Exp. Mar. Biol. Ecol. 

146: 193-203. 

Gerard, V. A. 1982. In situ water motion and nutrient uptake by the giant kelp 

Macrocystispyrifera. Mar. Biol. 69: 51-54. 

Gilfillan, E. S., D. S. Page, E. J. Harner and I? D. Boehm. 1993. Shoreline 

ecology program for Prince William Sound, AK following the Exxon fildez 

oil spill: Part 3-Biology. In Third symposium on environmental toxicology 

and risk assessment: Aquatic, plant and terrestrial. ASTM. Atlanta, GA. 

April 26-29,1993. 
Hawkins, S. J. and R. G. Hartnoll. 1983. Changes in a rocky shore community: 

An evaluation of monitoring. Mar. Environ. Res. 9: 131-181. 

Highsmith, R. C., M. S. Stekoll, W. E. Barber, L. Deysher, L. McDonald, D. 

Strickland and W. I? Erickson. 1992. Comprehensive assessment of coastal 

habitat. Draft preliminary status report. Volume I. Coastal habitat study no. 

1A. 438 p. 

Highsmith, R. C., M. S. Stekoll, W. E. Barber, L. McDonald, D. Strickland and 

W. I? Erickson. 1994. Comprehensive assessment of coastal habitat. Coastal 

habitat study no. 1A. Final report. Volume I. School of Fisheries and Ocean 

Sciences, Univ. Alaska Fairbanks. 796 p. 

Hiscock, K. [ed.]. 1985. Rocky shore survey and monitoring workshop. May 1st 

to 4th 1984. British Petroleum International Ltd., London. 

McGrath, D., I? A. King and E. M. Gosling. 1988. Evidence for the direct 

settlement of Mytilus edulis larvae on adult mussel beds. Mar. Ecol. Prog. Ser. 

47: 103-106. 

Muus, B. J. 1968. A field method for measuring "exposure" by means of plaster 

balls: A preliminary account. Sarsia 34: 61-68. 

Petersen, J. H. 1984. Larval settlement behavior in competing species: Mytih 

californianus Conrad and M. edulis L. J. Exp. Mar. Biol. Ecol. 82: q7-159. 

Petticrew, E. L. and J. Kalff. 1991. Calibration of a gypsum source for freshwater 

flow measurements. Can. J. Fish. Aquat. Sci. 48: 1244-1249. 

Seed, R. 1976. Ecology, p. 13-65. In B. L. Bayne [ed.], Marine mussels: Their 

ecology and physiology. IBP 10. Cambridge University Press. 

Venvey, J. 1952. On the ecology and distribution of cockle and mussel in the 

Dutch Waddensea, their role in sedimentation and the source of their food 

supply. Arch. Neerl. 2001.10: VI-239. 

Wethey, D. S. 1985. Local and regional variation in settlement and survival in the 

intertidal barnacle Semibalanus balanoides: Patterns and consequences, p. 194- 

202. In I? G. Moore and R. Seed [eds.], The ecology of rocky coasts. Hodder 

and Stoughton. 
North Slope Amphidromy Assessment 

Thomas C. Kline 

Prince William Sound Science Center 

Cordova, AK 99574 

John J. Goering 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7220 

Abstract 

Natural stable isotope abundances measured in tissues ofAlaska North Slope 

coregonineJishes reyect dferences in feeding habitat relative to size and age. This 

methodology is being developed to use as a tool for proxy analysis ofjsh behavior in 

future North Slope environmental monitoring studies. Development of the methodology consists of sampling arctic and least ciscos, broad whitefish, Dolly firden, and 

representative noncommercialJish and forage species through collaboration with 

existing sampling programs being conducted by the North Slope Borough Department of Wildlfe Management and BP Exploration through contracts to LGL 

Alaska Research Associates, Inc. Intensive sampling at a limited number ofsites is 

enabling an analysis ofpopulation structure using natural stable isotope abundance. 

Initial results of thejrstpd season conjrm that stable isotope data reJEect 

amphidrornous feeding modes. 

Introduction 

The Problem 

Fishes of the genus Coregonus numerically dominate coastal and fieshwaters of 

the Alaskan arctic coastline. In addition to being obligate freshwater spawners, 

they undergo feeding migrations into coastal waters during the summer. The 

migration passages used by these fishes have been subjected to physical alterations as a result of the industrial development necessary for oil exploration and 

extraction. Considerable effort has been made to ascertain whether structures 

such as causeways located in migration routes have had a detrimental effect on 

these species. Thus far, no detrimental effects have been detected using conventional research tools. However, subtle effects on migrational behavior with longterm consequences may not be detectable with the technologies currently being 

employed. An example of a potential effect of shifts in migrational behavior 

would be an alteration in life history feeding strategy. Evidence that different life 

history strategies exist on the North Slope is found in Teshekpuk Lake, where a 

portion of the least cisco and broad whitefish populations are thought to be nonmigratory because they grow at a slower rate compared to amphidromous populations (George et al., 1996). A ~otential consequence of industrial development 
could be increased dwarfism if migration is restricted. Fecundity loss leading to 

population reduction is another possible consequence if spawning ground access 

is made more difficult. New techniques that assess subtle changes in the migrational behaviors of these fishes could allay these fears. 

The Approach 

Large gradients in the natural abundance of 13C/12C and 15NP4N exist between 

fieshwater and marine habitats on the Alaskan arctic coastline. This is due to the 

existence of massive terrestrial peat deposits that provide an important carbon 

source (directly via peat-consuming insects and indirectly via respiration of peat 

carbon) to food chains existing there and the distinctive isotopic signatures of the 

peat deposits. Because stable isotope ratios are conserved during feeding processes, they make effective tracers of food sources enabling researchers to distinguish between peat and marine carbon. An ability to detect food-source 

signatures in fishes also enables the researcher to ascertain whether migration has 

taken place by determining where the sample was collected in relation to potential feeding locations. Evidence that isotopic signatures differ depending on 

amphidromous behavior and consequently carbon source was found in a pilot 

isotope study in 1993 conducted by Kline in collaboration with the North Slope 

Borough Department of Wildlife Management (DWM). The purpose of this 

project, North Slope Arnphidromy Assessment, is to investigate the use of 

isotope measurements as a proxy for amphidromous behavior. The goal is to 

determine the suitability of measuring the 13C/"C and 15NP4N ratios of a fish to 

quantify its migrational movements between fieshwater and marine habitats. The 

project sampling design was made to achieve this goal. 

Project Collaboration 

This project complements other research being conducted on the North Slope by 

the DWM and LGL Alaska Research Associates, Inc. for BP Exploration 

(Alaska) Inc. (BPX). Sampling was designed to complement these studies so that 

they can provide the basis for the Coastal Marine Institute (CMI) match requirements. Also by sampling alongside existing sampling, fish loss is minimized. That 

is, fish that are killed for another purpose are also being used for stable isotope 

measurement. This has helped to justify the required Alaska Department of Fish 

and Game collection permit. 

Background and Relevance to Framework Issues 

The DWM has been undertaking research on harvested and potentially 

harvestable fish populations that occur concomitantly with oil on the Alaska 

North Slope. This research has involved investigators outside of DWM, as well 

as their own personnel. Kline is currently collaborating with the DWM in a 

multi-disciplinary research effort on coregonine fishes ofTeshekpuk Lake (the 

largest lake on the Alaskan arctic coastal plain and third largest lake in Alaska) 

and the Chipp River. The latter, as well as other watersheds between Barrow and 
the Colville River, have recently been discovered to be important habitats for the 

recruitment of Bering and arctic cisco (Benny Gallaway, LGL Ecological Research Associates, Inc., Bryan, TX, pers. comm.). Kline's part in this investigation 

is to determine whether differences in feeding habits among the different species 

and species forms can be evidenced with stable carbon (C) and nitrogen (N) 

isotopic analyses. Preliminary data suggested that the dwarf form of the least 

cisco deviates from the isotopic composition of normal and intermediate forms. 

Two carbon isotope ratio clusters suggest there are at least two separate food 

chains, whereas the shift in nitrogen isotope ratio suggests a one-step trophic 

level shift or a different nitrogen source. Although Teshekpuk Lake broad 

whitefish stable isotope data with respect to form were not as clear cut, there was 

a significant difference in the carbon isotope distribution. These results corroborate other stable isotope fish studies conducted in this region that suggest significant isotope ratio gradients. Through exploitation of these gradients, we will gain 

a better understanding of fish ecology. 

This project will continue in collaboration with the DWM (Craig George et al.) 

and will expand the utilization of newly developed stable isotope abundance 

methodology at sites being monitored by BPX and ARCO Alaska (ARCO). 

This project embraces item #1 of the CMI Framework Issues. The results fi-om 

the Teshekpuk study were reported in a seminar sponsored by the Institute of 

Marine Science at the University of Alaska Fairbanks. This work which is 

currently in the from of a draft technical report submitted to the DWM is being 

reduced to a paper for submission to a peer-reviewed scientific journal. 

Potential Benefits in Relation to Mineral Exploitations 

Monitoring the subsistence and commercially harvested fish species (i.e., arctic 

and least ciscos, and broad whitefish) has been an ongoing process because of 

potential impacts resulting fiom oil development on the Alaska North Slope. 

Much of the focus has been on the impact of causeways altering the migratory 

behavior of these species (Gallaway et al., 1991). These species are classified as 

amphidromous because they migrate between the fieshwater and marine environments for nonreproductive activities, and anadromous because they must reproduce in freshwater. Maintenance of these populations depends on their continued 

ability to move back and forth between fieshwater and marine environments. The 

migratory pathways are complex because of the low topography and thermokarst 

features of the Arctic Coastal Plain and the intricate and tortuous pathways 

among lakes, streams, lagoons, and open water as well as the varied tolerance to 

salinity by the various fish species. The fish monitoring program has consisted of 

extensive monitoring stations in the developed area (e.g. Prudhoe Bay) and 

existing fisheries (e.g. Colville River). 

Exploration for oil to the west of Prudhoe Bay, including the Ikpikpuk watershed 

(including Teshekpuk Lake) has commenced (Craig George, DWM, pers. 
comm.), suggesting that potential impacts in this coastal area are imminent. 

Previous exploration and exploitation of North Slope oil has required the construction of roads and causeways that have potential impacts on amphidromous 

and anadromous fishes such as the least cisco and broad whitefish. A tremendous 

effort has been made to assess oil development impacts on fishes in the developed 

area to date. However, many questions remain unresolved, in particular, the effects 

of constructions on the migratory behavior of fishes. It has been difficult to assess 

whether the causeways are having a detrimental effect on fish populations using 

conventional fisheries methods (Gallaway et al., 1991). The purpose of this study 

is to assess the use of stable isotope data to determine the impact of oil development on the ecology of important subsistence and commercial fish species. 

Changes in the observed stable isotope gradients may be used to determine how 

migratory and consequently feeding behavior shifts in response to alterations of 

fish habitats. Habitat alteration fiom activities such as oil exploration and mining, 

e.g. causeway construction, may alter migratory pathways of anadromous and 

amphidromous fishes. Thus, population interactions may change. Potential 

evidence of change by stable isotope analyses may include: 

I) Forced overlapping of populations that were formerly separate; 

2) Alteration of the nature of nutritional sources; 

3) Shifts in the relationship of population characteristics with respect to 13C 

and 15N and habitat use, enabling prediction of potentially sensitive stages 

to environmental perturbation; and 

4) Shifts in other population characteristics such as parasitism, genetics and 

population structure (e.g. length at age and population age distribution) 

with concomitant isotopic change. 

Stable isotope analysis elucidates aspects of North Slope fish populations not 

available by other methods through: 

I) Furthering the isotopic characterization of fish populations in order to 

determine the spatial and temporal patterns of North Slope fish populations; 

2) Determining the interaction among populations by trophic status and 

food web characterization; and 

3) Assessing habitats and food chains important as nurseries for the recruitment of populations. 

Analyses in this study follow established isotope chemistry laboratory and data 

analysis protocols. Methods for synthesis of data have been established (Kline et 

al., 1989; Une, 1991). Laboratory work for this project provides student projects 

where students are directly involved in pre-mass-spectrometry laboratory aspects 

of the project. This project may also provide data for a possible Ph.D. thesis for 

C. George. Field studies are being conducted to address CMI Framework Issue 

#I to coincide with DWM needs for fish stock assessment. Presently, efforts are 
being concentrated in the western portion of the Ikpikpuk watershed (Chipp 

River). Similarly, field studies which address Framework Issue #2 are being 

conducted to coincide with BPX and ARC0 needs for fish stock assessment and 

impacts. The fusion of these studies with collaborating agencies comes in part 

fiom their role in matching CMI funding as well as facilitating sample collections 

within the operational constraints that exist in working in the arctic (e.g., the very 

short season and high financial costs). 

Applications of Amphidromy Assessment 

Stable isotope ratios are being used to characterize where individual fishes have 

fed by comparing the ratios found in the fishes to ratios found in various natural 

habitats. By generalizing characteristic isotopic signatures of feeding in fresh- and 

saltwater habitats, a mixing model can be established (Kline, 1991, Kline et al., 

1993) to quantify a "degree of amphidromy" on a per fish sample basis. By analyzing a reasonable sample size (number of fish), it will be possible to assess how a 

fish population is behaving. If behavior should shift over time, a concomitant 

isotope shift can be used to quantitatively assess the change. No other methodology currently exists that will provide such data or analysis. 

It may be necessary to build roads with culverts and causeways during future oil 

development in the study area. Such construction may reduce the migratory 

ability of coregonines (for example) thus restricting a greater proportion of the 

population to freshwater. Possible consequences of development, such as an 

increased proportion of dwarfism and reduction of population size, could be the 

result of a deprivation of coastal feeding grounds if the fish lose the high 13C 

marine signature that is now present. Similar shifts could occur within any of the 

watersheds of the Arctic Coastal Plain. Stable isotope chemistry shifts would 

thus provide direct evidence of oil development effects on fish populations. The 

use of the natural stable isotope abundance method enables a predictive capability 

in assessing oil development impact, thus embracing item #2 of the CMI fi-amework. 

Results and Discussion 

Objective (1 ) 

Establish baseline isotope attributes of unaffected populations before any 

development occurs. During and following development, fish populations 

can be monitored by looking for alterations in their expected isotope 

chemistry to determine if they are being excluded from feeding habitats. 

Stable isotope chemistry is a very powe&l tool for use in ecological 

studies because of naturally existing isotope gradients (Schell and Zieman, 

1989; Hesslein et al., 1991) and the fidelity of consumer-stable isotope 

ratios with the diet (Fry and Sherr, 1984; Owens 1987; Peterson and 

Howarth, 1987; Wada et al., 1991). 
In 1994, this objective was met by the field study to the Chipp River. In 

1995 and beyond, objective (I) will be met by similar field projects in 

collaboration with the DWM and LGL Alaska Research Associates, Inc. 

Species sampled include least cisco, broad whitefish, humpback whitefish, 

Dolly Varden and other salrnonids, representative other fishes for comparison, including obligate freshwater species, and potential fish forage 

species. 

Objective (2) 

Expand existing isotope studies in the developed area: a) the 

Sagavanirktok River and causeways; and b) the Colville River. Although 

behavioral changes may have taken place in the developed area, evidence 

in the Sagavanirktok (Lisa Stuby, M.S. Candidate of Schell, University of 

Alaska Fairbanks, pers. comm.) and Colville Rivers (Schell and Zieman, 

1989) suggests isotopic shifts similar to those observed in Teshekpuk Lake. 

In 1994, this objective was met through collaboration with BPX and their 

contractor LGL Alaska Research Associates, Inc. It is expected that this 

sampling will be continued. 

Species sampled include least cisco, arctic cisco, broad whitefish, Dolly 

Varden and other salmonids, representative other fishes for comparison, 

including obligate marine species, and potential fish forage species. 

1994 Sampling 

Sampling in the Chipp River system took place during the last ten days of July 

1994. The personnel left by boat from Barrow at ice-out. The field camp was 

established at subsistence site PK13 where gillnet and fyke net sampling sites 

were set up. Excursions were made downstream to a fyke net site at a lake 

confluent with the Chipp River and a gillnet site at the river mouth (Figure I). 

Fishes were collected daily and processed at the field camp. Processing included 

the determination of weight, length, sex, sexual maturity, and stomach content 

data for each fish. Otoliths were removed for age determination at a later date 

and tissues were sampled for stable isotope analysis. The stable isotope analyses of 

these samples are presented here. 

Verification of Isotopic Gradients 

Large isotopic ranges have been observed in fishes of the North American Arctic 

(Schell and Zieman, 1989, Hesslein et al., 1991). 613C from Schell and Zieman 

(1~8~) are plotted in Figure 2 for comparison with present data. Marine fishes 

(scul~ins and cod) had more positive 613C and freshwater fishes (grayling, 

longnose sucker, and burbot) had more negative 613C, whereas the 

amphidromous coregonines were intermediate and had greater 613C ranges 

consistent with the notion that 613C reflects feeding habitat. To further explain 

the isotopic gradients, Schell and Zieman (1989) measured 14C abundance. Broad 

whitefish were most 14C-depleted consistent with obtaining peat fossil-carbon. 

Grayling were less 14C-enriched, suggesting input of atmospherically-derived 
1994 Sampling Sit TESHEKPUK 

1994 Sampling Site 

94 Sampling Site 

04812 

Figure I. 1994 project sampling sites at Chipp River and subsistence fishing sites. 

carbon, most likely from feeding on insects utilizing terrestrial plants. Thus 13Cdepleted signatures may reflect terrestrial plant or peat carbon in fishes. Although 

only limited marine fishes were sampled at the Chipp River in 1994 (Figure 3), 

the more positive 613C of sculpin is consistent with an elevated marine 613C 

signature. A number of marine fish were sampled at Endicott in 1994 which will 

be used to better establish the marine 613C value. Other non-coregonine fishes 

sampled fiom the Chipp River in 1994 were 613C-depleted relative to sculpins 

(Figure 3). The rainbow smelt (anadromous) had intermediate values. Other 

fishes were more 613C-depleted. The most positive of these, the burbot, is slightly 

613C-enriched compared to the others because they are piscivorous and 613C 
Box Plots for Columns XI ..... X8 

-32 

SCUL COD LSCS ARCS BDWF GRAY LNSK BURB 

Prudhoe Fishes 

Figure z. Box plots of Pmdhoe Bay 6I3C of fishes fiom Schell and Zieman (197~). 

SCUL = sculpin, COD= cod, LSCS = least cisco, ARCS = arctic cisco, BDWF = broad 

whitefish, GWY = grayling, LNSK = longnose sucker, BURB = burbot. 

Box Plots for Columns XI ..... X7 

BURB GRAY LNSK PIKE SCUL RBSM 

Non-coregonine Fishes 

Figure 3. Box plots of 1994 Chipp River non-coregonine 613C. Abbreviations are the same as 

Figure z plus 9SP = ninespine stickleback, PIKE = northern pike, RBSM = rainbow smelt. 
increases by about one delta unit per trophic level feeding process (Fry and Sherr, 

1984; Wada et al., 1991). The pike was small and, though a piscivore, was probably 

feeding on smaller, lower trophic level fishes than the burbot. These data and 

future data of this type will provide validation of the freshwater-marine 613C 

gradient concept. 

Chipp River Coregonine Fishes 

The 613C data of the coregonine fishes sampled from the Chipp River in 1994 

were lipid-corrected using the method of McConnaughey and McRoy (1979) and 

are expressed as 613C in Figure 4 as a function of length. The size distributions 

reflect the size range attained by these species in this system. All fish > 300 mm 

show a consistent dichotomy whereby a portion of each species tends to deviate 

fi-om a 613C of -27, the apparent boundary between marine and freshwater 

carbon in the Chipp River system (Figure 4). Sub-100 mm least ciscos undergo a 

rapid change in 613C with respect to size. Assuming that these fish are of the 

same year class, change in feeding regime as evidenced by 613C may be reflected 

by size attained (100 mm fish being more negative in 613C than 80 mm fish). 

There appears to be a shift towards greater marine dependence in least ciscos 

-34 

0 100 200 300 400 500 600 700 

Fish length (mm) 

0 BDWF 

HBWF 

x LSCS 

Figure 4. 613C of three 1994 Chipp River coregonines. Abbreviations are the same as Figure 2 

plus HBWF = humpback whitefish. Each symbol represents averages of replicate analyses of 

individual fish. 
between 100 and 300 mm. There is a similar pattern in humpback whitefish. 

Broad whitefish showed the inverse 613C-length relationship at -60 mm, then an 

increase in 613C, as with the other species. The broad whitefish >400 mm (all 

mature adults) were strongly dichotomous, suggesting alternating marine and 

freshwater feeding with few intermediaries. This dichotomy also suggests that 

613C must change rapidly with migration between fresh- and saltwater and by 

extension, carbon turnover is rapid in large fish (< 1 year) contradicting the 

conjecture of Hesslein et al. (1993). The large broad whitefish are also considerably more negative than either the smaller broad whitefish or other coregonine 

species, probably reflecting feeding on carbon more directly related to peat (i.e. 

insect larvae, instead of zooplankton). From these data, a preliminary relationship 

between 613C and feeding habitat can be drawn: a 613C of coregonines > -26 is 

marine, and a 613C < -28 is freshwater, with intermediate values corresponding to 

transitional or estuarine feeding. 

Food Web Reconstruction 

Dual isotope plots enable the reconstruction of food webs as each isotope can 

independently confirm the flow of organic matter through feeding processes that 

have predictable effects on isotopic composition. 615N also enables a good assessment of trophic position (Fry, 1988; Cabana and Rasmussen, 1994). Broad whitefish were divided into size groups and compared to non-coregonines sampled 

SSP 

BURB 

A GRAY 

6 LNSK 

SCUL 

0 PIKE 

A RBSM 

o BDWF 450 

0 BDWF 150-400 

0 BDWF A00 

5 7 9 11 13 15 17 

Delta N-15 

5. Dual isotope plot of non-coregonines and broad whitefish sampled from the Chipp 

River in 1994. Each symbol represents averages of replicate analyses of individual fish. 
from the Chipp River (Figure 5). The distribution of broad whitefish stable 

isotope data thus elucidates the diversity of feeding exhibited by this species with 

respect to size. There are significant clusters of broad whitefish at 615N of - +12 

at 613C of - -26 and -33, suggesting a higher trophic position at times (predominant) and lower trophic positions at others, with the greatest marine carbon being 

at the lower trophic position (implied by lower 615N). The significant cluster at 

-33 departs strongly from other fishes, consistent with a specialist feeding mode. 

Broad whitefish had a wide range in 613C consistent with feeding migrations 

between habitats of low and high 13C. Chipp River 613C ranged from - -20 to 

-34, a much greater range than found in two broad whitefish populations near the 

Mackenzie River by Hesslein et al. (1991), i.e. - -21 to -25 in Kukjuktuk Creek 

and -24 to -28 in Travailent Lake. This difference in findings is partially explained by the more limited age classes and numbers sampled by Hesslein et al. 

(1991). The need for a large sample size of a given species is apparent with these 

data. This is particularly apparent in the dual isotope plot because of the broad 

range in values and the need for data clustering for interpretation. 

Chipp River vs. Teshekpuk Least Cisco 

There is good consistency in the 13C of least ciscos in the comparison of Chipp 

River and Teshekpuk Lake data (Figure 6). Any site-specific differences can be 

50 100 150 200 250 300 350 400 450 

Length (mm) 

Figure 6.1994 Chipp River least ciscos versus 1992 Teshekpuk Lake least cisco morphs. 

D = dwarf morph, I = intermediate form, N = normal form. 
attributed to feeding migrations. The data suggests that Chipp River least ciscos 

reside in fresh water until -250-300 mm when they become amphidromous. 

Normal-form least ciscos fiom Teshekpuk Lake commence marine feeding at 

-150 mm. The dwarf form is more similar to Chipp River least ciscos in terms of 

the regression line (Figure 6). However, Teshekpuk Lake dwarf-form least ciscos 

are all <200 mm. Thus it was deduced that the dwarfTeshekpuk Lake least ciscos 

are exhibiting a "normal" behavior and that the normal growth form represents an 

adaptive change in life history for Teshekpuk Lake. The stable isotope data 

provided evidence of the significance of amphidromous migrations and the 

different behavior modes for various populations of a given species. 

Prudhoe Bay Samples 

At the time of this writing, Prudhoe Bay samples collected in 1994 are being 

processed. These samples include three coregonine species, Dolly Varden, and 

other marine fishes (flounder and sculpin) as outlined in the project objectives. 

The initial stable isotope analyses reported here suggest that this technique will 

provide usefd data for amphidromy assessment, thus meeting the project's 

principal goal and providing a new tool useful for environmental assessment 

needed for oil exploration and development in the Alaskan Arctic Coastal Plain. 

References 

Fry, B. 1988. Food web structure on the Georges Bank from stable C, N, and S 

isotopic compositions. Limnol. Oceanogr. 33: 1182-1190. 

Fry,B. and E. B. Sherr. 1984. 613C measurements as indicators of carbon flow in 

marine and freshwater ecosystems. Contrib. Mar. Sci. 27: 13-47. 

Cabana, G. and J. B. Rasmussen. 1994. Modeling food chain structure and 

contaminant bioaccumulation using stable nitrogen isotopes. Nature 

372: 255-257. 

Gallaway, B. J., W. J. Gazey, J. M. Colonell, A. W. Niedoroda and C. J. 

Herlugson. 1991. The Endicott development project-preliminary assessment of impacts fi-om the first major offshore oil development in the Alaskan 

Arctic. Am. Fish. Soc. Symp. 11: 42-81. 

George, J. C., L. M. Philo and L. L. Moulton. 1996. Preliminary findings fiom 

fish surveys in Teshekpuk Lake. In J. B. Reynolds [ed.] Fish ecology in arctic 

North America. Am. Fish. Soc. Symp. In press. 

Hesslein, R. H., M. J. Capel, D. E. Fox and K. A. Hallard. 1991. Stable isotopes 

of sulfur, carbon, and nitrogen as indicators of trophic level and fish migration in the lower Mackenzie River basin, Canada. Can. J. Fish. Aquat. Sci. 

48: 2258-2265. 

Hesslein, R. H., K. A. Hallard and P. Ramdal. 1993. Replacement of sulfur, 

carbon, and nitrogen in tissue of growing broad whitefish (Coregonus nasur) in 
response to a change in diet traced by 634S, 613C, and 615N. Can. J. Fish. 

Aquat. Sci. 50: 2071-2076. 

Kline, T. C., Jr. 1991. The significance of marine-derived biogenic nitrogen in 

anadromous Pacific salmon freshwater food webs. Ph.D. thesis, Univ. Alaska 

Fairbanks. 114 p. 

Kline, T. C., Jr., J. J. Goering, 0. A. Mathisen, P. H. Poe and F'. L. Parker. 1989. 

Recycling of elements transported upstream by runs of Pacific salmon: I. 615N 

and 613C evidence in Sashin Creek, southeastern Alaska. Can. J. Fish. Aquat. 

Sci. 47: 136-144. 

Kline, T. C., Jr., J. J. Goering, 0. A. Mathisen, P. H. Poe, P. L. Parker and R. S. 

Scalan. 1993. Recycling of elements transported upstream by runs of Pacific 

salmon: 11. 615N and 613C evidence in the Kvichak River watershed, southwestern Alaska. Can. J. Fish. Aquat. Sci. 50: 2350-2365. 

McConnaughey, T. and C. P. McRoy. 1979. Food-web structure and the fractionation of carbon isotopes in the Bering Sea. Mar. Biol. 53: 257-262. 

Owens, N. J. F? 1987. Natural variations in 15N in the marine environment. Adv. 

Mar. Biol. 24: 389-451. 

Peterson, B. J. and R. W. Howarth. 1987. Sulfur, carbon and nitrogen isotopes 

used to trace organic matter flow in the salt-marsh estuaries of Sapelo Island, 

Georgia. Limnol. Oceanogr. 32: 1.195-1213. 

Schell, D. M. and P. J. Zieman. 1989. Natural carbon isotope tracers in Arctic 

aquatic food webs, p. 230-251. In P. W. Rundel, J. R. Ehleringer and K. A. 

Nagy [eds.] Stable isotopes in ecological research. Springer-Verlag. 

Wada, E., H. Mizutani and M. Minagawa. 1991. The use of stable isotopes for 

food web analysis. Crit. Rev. Food Sci. Nutr. 30: 361-371. 
Recruitment of Juvenile Flatfishes in 

Alaska: Habitat Preference at Kodiak Island 

Brenda L. Norcross 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, Alaska 99775-1 080 

Abstract 

The distribution and abundance ofjuvenile_flatJ;shes within the inshore waters of 

the Kodiak Archipelago, Alaska, have been examined during this ongoing 

interannualstudy. Analysis of data collected in 1991 and 1992 suggest the following 

conceptual models of_flatJ;sh distribution basedprimarily on depth and substrate. 

Age-0 rock sole are foundpredominantly in water depths less than 50 m on sand or 

mixed sand substrate within 10 km of bay mouths. Age-Ojathead sole are found 

predominantly in water depths greater than 40 m on mud or mixed mud substrate 

throughout bays. Age-0 Pat@ halibut are foundpredominantly in water depths less 

than 40 m on mixed sand substrate near or outside mouths of bays. Age-1 yellowjn 

sole are foundpredominantly in water depths less than 40 m on mixed substrate at 

upper reaches of bays. These habitat models were conjrmedfor Chiniak Bay during 

collections made in August 1993 and August 1994. 

Introduction 

Flatfishes are of strong economic importance in Alaskan waters, due to directed 

commercial and sport fisheries as well as to commercial bycatch, yet knowledge of 

the early life history of flatfishes and their habitat in Alaska has been minimal 

prior to this study. Inferences about the life history ofjuvenile flatfishes have been 

made from studies of the same species along the coasts of Oregon and Washington, or from related species in other parts of the world. Twelve species of potentially competitive flatfishes are found near Kodiak Island, Alaska (Rogers et al., 

1986; Norcross et al., 1993). The prime targets for commercial fisheries are Pacific 

halibut (Hilapoglossus stenolepis), flathead sole (Hipp~~lossoides elassodon), rock sole 

(Pleuronectes bilineatus), rex sole (Errex zachirus), and Dover sole (Microstomus 

pac$cus). There are also directed fisheries for English sole (Pleuronectes vetulw) 

and starry flounder (Platichthys stellatus). Bycatch includes yellowiin sole 

(Pleuronectes asper), Alaska plaice (Pleuronectes quadrituderculatus), butter sole 

(Pleuronectes isolepis), and sand sole (Psettichtbys melanostictus), which are marketed secondarily. An attempt is currently underway to develop a fishery for 

arrowtooth flounder (Atheresthes stomias) for surimi. Commercial bycatch of 

Pacific halibut has been the cause of premature closure of groundfish fisheries 

many times during the past decade. 
Intertidal zones, shallow coastal areas, protected bays, and estuaries are often 

considered vital as nursery areas for flatfishes (Tyler, 1971; Gibson, 1973; van der 

Veer and Bergman, 1986; Tanaka et al., 1989), and abundance and size distributions of juvenile flatfishes have often been related to depth, sediment size, and 

food availability. Flatfish nurseries are found in shallow waters, often in less than 

10 m (Edwards and Steele, 1968; Allen, 1988; van der Veer et al., 1991). Substrates 

of flatfish nurseries are reported as silt, mud, and fine to coarse sand (Poxton et 

al., 1982; Wyanski, 1~90). Shallow bays and estuaries are thought to serve as 

excellent nursery areas and ideal feeding habitat because of high insolation of the 

bottom, high water temperatures, the particular sediment types found in protected waters (Pearcy and Myers, 1974), and the good supply of nutrients from 

land drainage (Pihl and Rosenberg, 1982). 

Initial selection of sampling locations and sites along the coast of Kodiak Island 

began with the acknowledgement that the coastline of the Gulf of Alaska is more 

rugged and has a greater tidal range than flatfish nursery areas in other locations 

around the world. Kodiak Island is representative of the coastline of the Gulf of 

Alaska because it provides a variety of habitat fiom shallow, fine-grained tidal 

flats to deep and rocky areas. Chiniak Bay is the only region of Kodiak Island 

that is easily accessible via road from the town of Kodiak Chiniak Bay encompasses three inner bays which are protected to varying degrees (Figure I: 

Womens, Middle, and Kalsin Bays); it also provides relatively accessible and 

unprotected zones outside the mouths of these bays. Prior to this funding, fishes 

and physical data were collected during 1991 and 1992 from all major bays and 

straits along the perimeter of Kodiak Island. Sample collection was continued 

during 1993 and 1994 as a result of this funding; however, collections were limited 

to Chiniak Bay during 1993, and to Chiniak Bay and Kazakof Bay (on Afognak 

Island) during 1994. 

This project describes and analyzes the recruitment of juvenile flatfishes, especially as influenced by habitat, to inshore waters of Kodiak Island, Alaska. The 

overall objectives of this project have been to: 

I) Iden* nursery grounds for juvenile flatfishes; 

2) Characterize those areas according to physical and biological parameters; 

and 

3) Develop indices of relative abundance of recruitment for as many species 

as the data allow. 

Analysis of data collected in Chiniak Bay during 1992,1993, and 1994 was funded 

primarily by the Coastal Marine Institute (CMI). Dietary analysis of flatfishes 

captured during 1991 was partially funded by CMI. 

During the first two years of sampling (1~~1-92), all major bays along the perimeter of Kodiak Island were sampled in order to form a broadly based characterization of flatfish nursery areas around Kodiak. The considered parameters 
Figure I. Permanent stations within Chiniak Bay, Kodiak Island. 

included location in the bay, depth, bottom temperature, bottom salinity, and 

sediment type. There were overlapping distributions for the most abundant 

juvenile flatfishes ages 0 and age-1 rock sole, ello ow fin sole, flathead sole, and 

Pacific halibut), yet patterns of peak abundance were unique to each species. The 

following conceptual models of the physical parameters most descriptive of 

flatfish nursery habitat have been developed based on the 1991-1992 distribution 

of flatfishes around Kodiak Island (Norcross et al., 1995a). Age-0 rock sole are 

found predominantly in water depths less than 50 m on sand or mixed sand 

substrate within 10 km of bay mouths. Age-0 flathead sole are found predominantly in water depths greater than 40 m on mud or mixed mud substrate 

throughout bays. Age-0 Pacific halibut are found predominantly in water depths 

less than 40 m on mixed sand substrate near or outside mouths of bays. Age-1 

yellowfin sole are found predominantly in water depths less than 40 m on mixed 

substrate in upper reaches of bays. 
CMI Framework Issues addressed by this study are as follows: 

I) Studies to improve understanding of the affected marine, coastal, or 

human environment; 

2) Modeling studies of environmental, social, and economic processes to 

improve predictive capabilities and to define information needs; 

3) Experimental studies to improve understanding of environmental processes or the causes and effects of OCS activities; 

4) Projects which design or establish mechanisms or protocols for the 

sharing of data or information regarding marine or coastal resources or 

human activities to support prudent management of oil and gas and 

marine mineral resources; 

This study will result in a better understanding of the potentially affected marine 

environment and its resources (Framework Issue #I) by further examining past 

data collections (Issue #4) and using them to produce conceptual habitat models 

(Issue #2). In future years, these habitat models will be linked to experimental 

results of exposure of flatfishes to oiled sediments (Issue #3). 

These conceptual models can be used to predict prime habitat for individual 

species ofjuvenile flatfish and, combined with possible trajectories of an oil spill 

or areas of chronic seepage, will suggest the most vulnerable geographic locations 

and species of fish. These models may be used to begin assessment of the possible 

impact of oil development on flatfish communities. 

Results and Discussion 

Field work funded by this project included the continuance of annual collections 

within Chiniak Bay on Kodiak Island during August (1993: Cruise KI9301; 1994: 

Cruise KI9403), as well as auxiliary collections within Chiniak Bay (June 1994: 

Cruise KI9401) and within Kazakof Bay on Afognak Island (August 1994: Cruise 

KI9402). Additional data collected within Chiniak Bay during November 1993 

were made available by the National Marine Fisheries Service (NMFS), Kodiak 

Laboratory. The primary objective for all collections was to evaluate the proposed 

conceptual models ofjuvenile flatfish distribution developed for Kodiak Island 

(Norcross et al., 1995a). 

All collections in Chiniak Bay during 1993 and 1994 were land-based day trips 

which employed a 24-foot Boston Whaler owned and operated by NMFS 

Kodiak. Sampling at each station included a fish trawl, conductivity, temperature 

and depth (CTD) cast, and sediment grab. Fishes were collected during tenminute tows with a 3.0 m plumb staffbeam trawl equipped with a double tickler 

chain, 7 mm square mesh bag, and 4 mm mesh codend liner. Fishes were identified and measured; ages of flatfishes were estimated based on length. Catch-perunit-effort (CPUE) was calculated based on a ten-minute tow time. 
Tasks: 

I) Complete analysis of 1992 samples, including graphical analysis, statistical 

analysis, reports, and publications (completed). 

2) Sample Kalsin, Middle, and Womens Bays in 1993 to keep time series of 

baseline data intact to quantify interannual variation (completed; additional 

collections in these bays and within Kazakof Bay, Afopak Island, were 

completed in 1994). 

3) Analysis of 1993 samples, including graphical analysis (complete4 an 

additionalgraphical analysis $1994 collections was done) and statistical 

analysis (in progress). 

4) Comparisons among 1991,1992, and 1993 results to quantify interannual 

variation (comparison ofIgpr and 1992 completed pNorcross et aL, 1995bI; 

firther comparisons in progress; additionally the 1994 collections will be compared with previous years). 

5) Community analysis of all fishes, not just flatfishes, in relation to their 

physical environment (in progress). 

1993 Collections 

Twenty-eight stations were occupied within Chiniak Bay during cruise KI9301, 

August 1993, resulting in a quantitative (cumulative CPUE) catch of flatfishes of 

2798. The quantitative catch fiom ten stations during KI9302, November 1993 

was 968, for an average CPUE of 99 flatfishes per station during KI9301 and 97 

flatfishes per station during IU9302. With minor deviations, data fiom both 

cruises confirmed the conceptual models ofjuvenile flatfish habitat (Norcross et 

al., 1995a). 

1994 Collections 

Twelve stations within Chiniak Bay were occupied during Cruise KI9401, June 

1994. Objectives of this cruise included the collection of data for comparison with 

flatfish distribution models, a preliminary examination of flatfish presence in 

Chiniak Bay during early summer, and length at age estimations. The quantitative catch of flatfishes amounted to 989, for an average CPUE of 82 flatfishes per 

station. 

Cruise KT9402 consisted of 32 stations in Kazakof Bay, Afognak Island, occupied 

during August 1994. The purpose of this cruise was to collect data for comparison 

with flatfish distribution models, and to produce a baseline survey of groundfishes 

in Kazakof Bay. The quantitative catch of flatfishes was 453, for an average 

CPUE of 15 flatfishes per station. 

Cruise KI9403, August 1994, included collections at 30 stations in Chiniak Bay. 

Twenty-one permanent (previously occupied) stations in Middle and Kalsin 

Bays, within Chiniak Bay, were sampled for comparisons of annual species 

composition and abundance. Nine new stations were established to give breadth 

to the sampling design. Seven of these new stations were near or outside the 
mouth of Kalsin and Middle Bays and deeper than had been previously sampled 

in this area. Sample depths ranged from 1 to 120 m. The quantitative catch of 

flatfishes captured during KT9403 was 13,993, and the average CPUE was 161 

flatfishes per station. Due partially to increased sampling effort during KI9403, 

the number of captured flatfishes was considerably greater than had been caught 

in 1991,1992, and 1993. The large number of captured flatfishes during KI9403 

may also be due to increased recruitment. 

Multi-year Analyses of Chiniak Bay 

The distribution of age-0 rock sole, flathead sole, Pacific halibut, and age-1 

yellowfin sole captured within Chiniak Bay in 1993 and 1994 closely followed the 

conceptual distributions predicted based on 1991 and 1992 data from all of Kodiak 

Island (Norcross et al., 1995a). One addition to the modelled distribution, as 

observed in the 1994 field season, is that age-0 flathead sole are also found at the 

bay mouth and outside the bay. This results fiom the fact that greater distances 

outside Middle and Kalsin Bays were sampled in the 1994 season than had been 

previously sampled. 

In addition to the trawls completed in Chiniak Bay during KI9301 and KI9403, 

stations were sampled with repetitive tows and scuba dives in order to statistically 

compare the efficiency of beam trawl versus scuba divers in identifying and 

quantifjrlng flatfishes on different bottom types. Data collected at these trawlldive 

stations sampled during 1993 and 1994 will be used to determine whether scuba 

divers may be used interchangeably with beam trawl tows in areas and on substrates where trawling is ineffective or impossible. 

Manuscripts 

Funding fiom CMI assisted with analysis of data collected in 1991 and 1992 for 

juvenile flatfish distribution and feeding. Thus far, three manuscripts based on 

these data have been accepted for publication and are available upon request. 

Copies have been forwarded to the project contracting officer's technical representative (COTR). The distribution and abundance of flatfishes captured during 

August 1991 was evaluated by discriminant analysis in the manuscript "Nursery 

area characteristics of Pleuronectids in coastal Alaska, USA" (Norcross et al., 

1995a), which has been accepted for publication in the Netherland Journal ofsea 

Research. Multivariate analysis of distribution and abundance of flatfishes captured during 1991 and 1992 was summarized in the manuscript "Habitat models 

for juvenile Pleuronectids around Kodiak Island, Alaska, USA" (Norcross et al., 

1995b). Feeding diversity of juvenile flatfishes was described in "Diet diversity as a 

mechanism for partitioning nursery grounds of Pleuronectids" (Holladay and 

Norcross 1~~5). These last two manuscripts were presented orally at the International Symposium on North Pacific Flatfish, held October 26-28,1994, in Anchorage, Alaska, and will be ~ublished in the proceedings of that symposium. 
Related Projects Assisted Through This Funding 

Live juvenile flatfishes were captured during 1992-94 field work for a separate 

laboratory study (Moles et al., 1994; Moles and Norcross, 1995) to assess sediment 

preferences of various juvenile flatfish species. The lab study addressed the 

response of flatfishes to various concentrations of petroleum hydrocarbons in 

sediment, submitted fishes to physiological tests which assess the effect of nonavoidance of oiled sediment on the survivability of the fish, and provided a 

monitor for rates of growth, feeding, and respiration during long-term (chronic) 

exposure to low levels of oiled sediments. 

Preliminary Conclusions 

The conceptual models of flatfish distribution (Norcross et al., 1gg5b) based on 

1991-92 data were verified during collections within Chiniak Bay during 1993 and 

1994. As in 1991-92, station locations were selected based on depth and sediment 

strata, and data were analyzed using the physical parameters of location in the 

bay, depth, bottom temperature, bottom salinity, and sediment type. The four 

years of data now available on physical parameters and flatfish abundances within 

Chiniak Bay has enabled us to narrow the scope of collections proposed for 1995 

collections (Table I, Figure I). Comparisons of fish abundance and distribution 

from 1991 through 1994 show differences among species and among stations, as 

well as interannual differences. In particular, the distribution of rock sole and 

flathead sole appear to be strongly related to depth and substrate type (Figure I, 

Table I). There appears to be no relation to temperature and salinity, therefore 

these parameters are not shown in the attached table. In the future, depth and 

substrate patterns will be examined in more detail and other parameters which 

may affect the distribution of the abundant flatfishes will be investigated. Key 

habitat characteristics for each species will then be discerned so that their abundances can be monitored over time. 

Acknowledgements 

Data analysis for 1993 and 1994 and report writing were performed by Brenda 

Holladay and Sherri Dressel. Data analysis for 1991-92 comparisons were done by 

Franz Muter. Field sampling was conducted by Brenda Holladay, Franz Muter, 

and Sherri Dressel of the University of Alaska Fairbanks, and Eric Munk, C. 

Braxton Dew, and Pete Cummiskey of NMFS Kodiak. The principal investigator 

was involved in all phases of the project. 
Table I. Summary of flatfish catch-per-unit-effort within Chiniak Bay, 1991-94. Stations beginning with "K" are in Kalsin 

Bay and with "Mn are in Middle Bay. hand, ssandy, Mzmud, m~muddy, Gzgravel. 

Rock sole Yellowfin sole Pacific halibut Flathead sole 

Station Depth Sediment 1991 1992 1993 1994 1991 1992 1993 1994 1991 1992 1993 1994 1991 1992 1993 1994 

KA 0-5 S 80 66 35 64 5 0 2 0 0 0 116 0000 

KA 0-5 S - 16 20 80 -201 - 3 023 -000 

KB 5-10 S 84 136 40 124 30313 3 7225 0000 

KC 10-20 mS 102 251 200 429 28 24 16 16 3 23 8 40 0100 

KD 20-30 SM 24 - 32 248 32-20 30-08 2 -415 

KE 30-40 SM - - 0 6 --02 --00 - - 166 42 

KF 50-60 SM - - 0 0 --00 --00 - - 139 209 

KG 60-70 SM - - 2 1 --00 --00 - - 104 22 

KH 70-80 SM 0-- 0 0 - - 0 0 - - 0 6-- 1 

KT 80-90 mS --- 0 - - - 0 - - - 0 - - - 33 

KJ 90-100 sM -- - 0 - - - 0 - - - 0 - - - 0 

KK 110-120 mS -- - 0 - - - 0 - - - 0 --- 0 

ML 0-5 S 1 1 109 0 0 0 8 0 0 1 60 26 0100 

MM 5-10 mS 64 76 32 0 81020 7 13 15 15 0000 

MN 5-10 mS 35 88 19 6 31210 3 6810 0000 

MO 10-20 mS --- 2 - - - 0 - - - 6 --- 0 

MP 10-20 mS 29 - 48 9 31 - 10 0 3 -812 3-31 

MQ 20-30 mS 71 188 53 220 12412 1 16 0 68 11800 

MR 30-40 SG 22 - 3 25 0-00 0-00 0-35 

MS 50-60 mS 1100 0 0 0 0 0 0 0 0 0 26 303 65 14 

MT 60-70 mS - - 0 0 --00 --00 --23 

MU 70-80 mS - - 0 1 --00 --00 - -013 

Total 523 822 593 1215 250 35 43 24 50 69 102 249 38 323 486 358 

References 

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Alamitos Bay-Long Beach Harbor, California, 1983-1985. Bull. South. Calif. 

Acad. Sci. 87: 19-30. 

Edwards, R. and J. H. Steele. 1968. The ecology of 0-group plaice and common 

dabs at Loch Ewe. I. Population and food. J. Exp. Mar. Biol. Ecol. 2: 215-238. 

Gibson, R. N. 1973. The intertidal movements and distribution of young fish on 

a sand beach with special reference to the plaice (Pleuronectesplatessa L.). J. 

Exp. Mar. Biol. Ecol. 12: 79-103. 
Holladay, B. A. and B. L. Norcross. 1995. Diet diversity as a mechanism for 

partitioning nursery grounds of Pleuronectids. Proc. Int. Symp. on North 

Pacific Flatfish. In press. 

Moles, A. and B. L. Norcross. 1995. Sediment preference in juvenile Pacific 

flatfish. Neth. J. Sea Res. In press. 

Moles, A., S. Rice and B. L. Norcross. 1994. Non-avoidance of hydrocarbon 

laden sediments by juvenile flatfishes. Neth. J. Sea Res. 320/4): 361-367. 

Norcross, B. L., B. A. Holladay and M. Frandsen. 1993. Recruitment of juvenile 

flatfish in Alaska, Phase I. Final contract report, Inst. Mar. Sci., Univ. Alaska 

Fairbanks (unpubl. rep.). 504 p. 

Norcross, B. L., B. A. Holladay and F. J. Miiter. 1995a. Nursery area characteristics of Pleuronectids in coastal Alaska, U.S.A. Neth. J. Sea Res. In press. 

Norcross, B. L., F. J. Miiter and B. A. Holladay. 1995b. Habitat models for 

juvenile Pleuronectids around Kodiak Island, Alaska, U.S.A. Proc. Int. Symp. 

on North Pacific Flatfish. In press. 

Pearcy, W. G. and S. S. Myers. 1974. Larval fishes of Yaquina Bay, Oregon: A 

nursery ground for marine fishes? Fish. Bull. U.S. 72: 201-213. 

Pihl, L. and R. Rosenberg. 1982. Production, abundance, and biomass of mobile 

epibenthic marine fauna in shallow waters, western Sweden. J. Exp. Mar. 

Biol. Ecol. 57: 273-301. 

Poxton, M. G., A. Eleftheriou and A. D. McIntyre. 1982. The population 

dynamics of 0-group flatfish on nursery grounds in the Clyde Sea area. 

Estuarine Coastal Shelf Sci. 14: 265-282. 

Rogers, D. E., B. J. Rogers and R. J. Rosenthal. 1986. The near-shore fishes, p. 

399-416. In D. W. Hood and S. T. Zimmerman [eds.] The Gulf of Alaska, 

physical environment and biological resources. U.S. Dept. of the Interior 

Minerals Management Service OCS study. 

Tanaka, M., T. Goto, M. Tomiyama and H. Sudo. 1989. Immigration, settlement 

and mortality of flounder (Paralichthys olivaceus) larvae and juveniles in a 

nursery ground, Shijiki Bay, Japan. Neth. J. Sea Res. 24: 57-67. 

Tyler, A. V. 1971. Surges of winter flounder, Pseudopleuronectes americanus, into 

the intertidal zone. J. Fish. Res. Bd. Can. 28: 1727-1732. 

van der Veer, H. W. and M. J. N. Bergman. 1986. Development of tidally related 

behaviour of a newly settled 0-group plaice (Pleuronectesplatessa) population 

in the western Wadden Sea. Mar. Ecol. Prog. Ser. 31: 121-129. 

van der Veer, H. W., M. J. N. Bergman, R. Dapper and J. I. J. Witte. 1991. 

Population dynamics of an intertidal 0-group flounder PlatichthysJlesus 

population in the western Dutch Wadden Sea. Mar. Ecol. Prog. Ser. 

73: 1241-148. 

Wyanski, D. M. 1990. Patterns of habitat utilization in 0-age summer flounder 

(Paralichthys dentatus). unpubl. M.S. thesis, College ofWiam and Mary. 54 p. 
Juvenile Flatfish Habitat in Kachemak Bay: 

A Pilot Study 

Addendum to 

Recruitment of Juvenile Flatfishes in Alaska: 

Habitat Preference at Kodiak Island 

Brenda L. Norcross 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, Alaska 99775-1 080 

Abstract 

The objective of this study was to examine and identZfj nearshore habitat used as 

nursery areas by juvenilejatJ;shes in Kachemak Bay, Alaska, and to characterize 

the juvenile habitat based on physical oceanographic parameters (including depth, 

sediment grain size, temperature, salinity, and distanceporn shore) and biological 

factors (stomach contents andfood availability). This pilot was intended as a 

feasibility study to survey an accessible portion of Lower Cook Inlet. Samples were 

collected September 24--0,1994, at 37 stations (Figure I). A total of 3435Jishes 

were captured with a 3.0 m beam trawl, of which 42.2% wereja@hes. The most 

abundant juvenile (age-0 and age-l)ja@shes were rock sole (Pleuronectes 

bilineatus), jathead sole (Hipp~~lossoideslassodon), Pac@c halibut (Hippoglossus 

stenolepis), awowtoothjounder (Atherestes stomias), andyellowjn sole 

(Pleuronectes asper). Distribution of rock sole,jathead sole, halibut, andyellowjn 

sole during September in Kachemak Bay was compared with conceptual models of 

ja@h distribution developed for August in Chiniak Bay, Kodiak (Norcross et al., 

1995). AlthoughJta@shes in Kachemak Bay were sometimes distributed over a 

wider range of depths than in Chiniak Bay, the highest abundances of each species 

were within the bounds of the conceptual models. 

Introduction 

Areas in Cook Inlet, Alaska, are scheduled to be open for oil and gas leases soon. 

In 1996 the federal government will make portions of Kachemak Bay near Homer 

available for oil and gas lease. Cook Inlet is a productive estuary which supports 

many commercial and sport fisheries, including a thriving halibut charter industry. Flatfishes are vulnerable to oil exposure because of their close interaction with 

the sediment (Moles et al., 1994; Moles and Norcross, 1~95). Flatfishes bury 

themselves in the sediment for protection (Tanaka, ~ggo), avoidance of currents, 

and conservation of energy (Gibson and Robb, 1992). Because feeding may 

involve taking sediment and prey in mouth and sieving the sediment (Hicks, 

1984), flatfishes could be directly exposed to oil through ingestion of benthic prey 
Figure I. Consecutive station locations sampled during C19401, September 1994. 

as well as contact with the substrate. To date, the limited research on flatfishes in 

Cook Inlet has focused on adult fishes. Prior to this pilot study there was no 

information about the role of Kachemak Bay as a nursery ground for juvenile 

flatfishes. 

Most juvenile flatfishes are found in nearshore shallow areas which have the 

advantages of higher temperatures, lower predation risk, abundant food, and 

appropriate substrata (Gibson, 1994; Minami and Tanaka, 1992). Distribution 

within the nursery grounds varies with species, locality, season, and year (Minami 

and Tanaka, 1992). There are significant differences in the distribution of flatfishes 

between and within families; these differences allow coexistence of a multitude of 

flatfish species on the continental shelfand slope (Minami and Tanaka 1~92). 

Depth strongly influences the distribution of some flatfishes, as observed in 

coastal areas of the Southern Bight of the North Sea, and is one of the most 

important determinants of sole (Solea solea) distribution, in conjunction with 

substrate type and prey availability (Rogers, 1992). Walsh (1992) found the 

distribution of yellowtail flounder (Pleuronectes femginea) to be dependent more 

on depth than temperature because the species can tolerate a wide range of 

temperature fluctuations. 

Sediment size is an important factor influencing the distribution of flatfishes; 

individual species can distinguish between and select sediments on the basis of 

their grain size (Gibson and Robb, 1992; Walsh 1992; Gibson, 1994; Moles and 
Norcross, 1995). Because juveniles actively choose grain size during settlement, 

grain size is a parameter which is useful for fine-scale description of flatfish 

distribution. Thus, measurements of grain size provide insight into mechanisms 

of predator avoidance, energy conservation, and feeding strategy. Although the 

underlying causes of the association between sediment grain size and flatfish 

habitat are unknown, physical conditions and benthic organisms are both correlated with sediment structure and probably play a role in the distribution of 

juvenile flatfishes (Gibson and Robb, 1992). Experimental evidence suggests that 

juvenile flatfishes actively choose substrate based on grain size because it relates 

to their ability to bury effectively and avoid predation. Burying behavior has been 

most frequently attributed to predation avoidance, but may also be a mechanism 

to conserve energy (Gibson and Robb, 1992). 

In laboratory and field studies, flatfishes have a strong preference for specific 

grain sizes. In fact, they will remain on favored sediment even if that sediment is 

polluted with oil while an unoiled, less favored grain size is available (Moles et al., 

1994). Rock sole prefer sand, yellowfin sole prefer mixed muusand, and Pacific 

halibut prefer muusand or sand (Moles et al., 1994; Moles and Norcross, 1995). 

Field research in Alaska provides examples of flatfish species correlated with 

sediment size. Norcross et al. (1995) found rock sole on sand or mixed sand 

substrate, flathead sole on mud or mixed mud substrates, Pacific halibut on mixed 

sand, and yellowfin sole on mixed substrate. In the North Sea, plaice (Pleuronectes 

platessa) are more densely populated on sandy flats than muddy areas (Berghahn, 

1986; Pihl and Veer, 19~2). Muddy sediments are preferred by flounder (Platichthys 

jesus) and sole (van der Veer et al., 1991). 

Temperature affects feeding and growth rates, as each species has a critical 

thermal range. Because flatfish species may actively change their distribution to 

alternate depths for energy conservation and optimal temperature, the distribution ofjuvenile flatfishes in nursery areas varies spatially and seasonally by species. 

Frank et al. (1992) found horizontal distributions of age-0 American plaice 

(Hippoglossoidesplatessoides), yellowtail flounder (Pleuronectes ferruginea), and 

witch flounder (Glyptocephalus ynoglossus) to correspond significantly to the 

bottom temperature distributions around the southern Grand Bank 

The objectives of this pilot study were to: 

I) Establish that nursery areas for juvenile flatfishes do exist in Kachemak 

Bay; and 

2) Characterize the most important parameters which define flatfish nursery 

areas in Kachemak Bay. 

This study addressed Framework Issue #2 in that the conceptual habitat models 

developed around Kodiak Island (Norcross et al., 1995) were used to design the 

sampling plan and were compared to the distribution of juveniles in Kachemak 

Bay. Age-0 rock sole are found predominantly in water depths less than 50 m on 
sand or mixed sand substrate within 10 krn of bay mouths. Age-0 flathead sole 

are found predominantly in water depths greater than 40 m on mud or mixed 

mud substrate throughout bays. Age-0 Pacific halibut are found predominantly in 

water depths less than 40 m on mixed sand substrate near or outside mouths of 

bays. Age-1 yellowfin sole are found predominantly in water depths less than 40 

m on mixed substrate at upper reaches of bays. In the future, with the inclusion of 

Kachemak Bay seasonal distribution data, these habitat models will be refined, 

and should be useful in identifying flatfish nursery habitats which could potentially be impacted by oil and gas development. 

Framework Issue #3 was addressed through this study and a related study conducted at the National Marine Fisheries Service (NMFS) Auke Bay Lab, where 

Adam Moles is conducting laboratory experiments on the physiological affects of 

juvenile flatfishes exposed to oiled sediments. Moles is currently a Ph.D. student 

working with Norcross and is funded by NMFS. The lab studies will include 

survival and growth rates on oiled and unoiled sediments (Moles, et.al., 1994; 

Moles and Norcross, 1995). The results of Moles' study will enhance and be 

incorporated in the critical habitat models developed resulting from the 1994-96 

field work. 

Results and Discussion 

Cruise CI9401 consisted of land-based collections conducted in Kasitsna, 

Jackolof, and Tutka Bays and Sadie Cove (Figure I) from September 24-30,1994. 

Based out of the University of Alaska School of Fisheries and Ocean Science / 

Institute of Marine Science Kasitsna Bay Laboratory near Seldovia, Alaska, 37 

stations were sampled from a 9.3 m aluminum Munson skiff. Collections ranged 

in depth from 1 to 80 m. A total of 3435 fishes, including nine species of flatfish, 

were captured. Sampling at each station included a fish trawl, conductivity, 

temperature and depth (CTD) cast, and sediment grab. Fishes were collected 

during ten-minute tows with a 3.0 m plumb staff beam trawl equipped with a 

double tickler chain, 7 mm square mesh bag, and 4 mm mesh codend liner. All 

fishes were identified, and then counted and measured using a Limnoterra 

electronic fish measuring board (FMB IV). Ages of the juvenile flatfishes were 

estimated based on length. The catch-per-unit-effort was calculated based on a 

ten-minute tow time. 

Tasks: 

I) Sample nearshore areas in Kachemak Bay at sites associated with 

Highsmith's benthic sampling to locate juvenile flatfishes. Measure related 

physical parameters (completed). The physical parameters measured include 

depth, sediment grain size, temperature, salinity, tidal stage, light stage, 

and distance from shore. The biological factors include the measurement 

of volatile organics in the sediments and the presence of associated species. 

Since flatfishes in this area were distributed deeper than anticipated based 
on Kodiak models, flatfish sampling did not overlap with the intertidal 

areas sampled by Highsmith as was intended. In addition, Highsmith's 

sites were very shallow and covered too small an area to be sampled 

adequately with the plumbstaff beam trawl. In order to sample juvenile 

flatfishes that were in deeper water, it was necessary to expand sampling to 

cover more of Kachemak Bay than was originally planned. 

2) Conduct graphical analyses of the distribution of flatfishes with respect to 

physical variables (completed). 

3) Analyze stomach contents of most abundant flatfishes (currently in 

progress). 

4) Conduct graphical and statistical analyses of stomach contents with 

respect to physical variables and Highsmith's results on benthic composition (this task is dependent on Highsmith$ analysis; however, the measurement 

ofpercent carbon for each station as a relative indicator of food availability has 

been completed, and these data may used in analyses related to stomach contents). 

5) Relate the distribution and stomach content analyses of fishes to a relative 

measure of flushing used in Highsmith's project to indicate recruitment 

rate of benthic organisms (the completion of this task is dependent on 

HighsmithS analysis). 

6) Relate laboratory experiments which quantify the effects of non-avoidance 

of hydrocarbon-laden sediments to field distribution of flatfishes (this is a 

long range goal based on comparisons with Moles' work and wilI be done at a 

later date; more information concerning juvenileja$ish distribution in 

Kachemak Bay will be obtained in a subsequent study beingfinded under a 

separate contract). 

The habitats of juvenile (age-0 and age-1) flatfishes were analyzed to characterize 

nursery grounds as described below: 

One age-0 Pacific sanddab (Citharichthys sordidus) was captured at a mean 

depth of 31.5 m and a bottom temperature of 9.50C. The bottom salinity 

was 30.3 PSU, and the sediment type was muddy sand. 

All age-0 and age-1 arrowtooth flounder (Atheresthes stomias) were captured at depths 2 30 m. They were in waters with a bottom temperature 

between 9.2-9.7T and the bottom salinity was 30.3-31.1 PSU. The 

sediment was predominately muddy sand and gravelly muddy sand. 

Age-1 rex sole (Errex zachirus) were captured in depths of 50-65 m. They 

were only in waters with a temperature range of 9.5-9.70C. The bottom 

salinity ranged from 30.7 to 31.0 PSU. Rex sole were found only on 

muddy sand and gravelly muddy sand. 

All flathead sole (Hipp~~lossoides elassodon) age-0 and age-1 were captured 

at depths of 30-70 m. The bottom temperatures ranged from 9.3 to 9.7T. 

Bottom salinity ranged from 30.3 to 31.0 PSU, with a concentration at 

30.7 PSU. The sediment was predominately gravelly mud for age-0. 

Age-1 flathead sole were usually found on mixed substrate of muddy sand 

and gravelly mud. 
Age-0 Pacific halibut (Hippoglossus stenolepis) were captured at depths of 

5 to 60 m, but were concentrated at depths I 40 m. They were captured at 

bottom temperatures of 9.2-9.70C. The bottom salinity ranged from 30.3 

to 31.0 PSU, and they were mainly captured at 30.3-30.6 PSU. Age-0 

halibut were found primarily on sand mixed with mud andlor gravel. 

No age-0 Dover sole (MicrostornuspacIf;cw) were captured, as they are 

plankton larvae until they reach 45 mm in length (Matarese et al., 1989). 

One age-1 Dover sole was captured at a station in Kachemak Bay 

(CS#19) with a bottom temperature of 9.60C and bottom salinity 30.7 

PSU Depth was between 50-60 m and the sediment type was muddy 

sand. 

One age-0 yellowfin sole (Pleuronectes asper) was captured. It was at 

CS#31 off MacDonald spit at a mean depth of 32 m, a bottom temperature 9.50C7 and bottom salinity 30.3 PSU, and sediment type muddy sand. 

Age-1 yellowfin were captured at depths of 10 to 60 m, but were concentrated around 30 m. They were mainly captured at a bottom temperature 

of 9.50C and a bottom salinity of 30.3 PSU, but were found in the 30.3- 

30.7 PSU range. It is noteworthy that age-1 yellowfin sole were captured 

at depths 140 m, because during the four years of collection near Kodiak 

Island (Norcross, 1991-94 unpublished data), they have never been captured at depths greater than 40 m. Age-1 were primarily captured on 

muddy sand. 

Age-0 and age-1 rock sole (Pleuronectes bilineatus) were captured to depths 

of 56 m, but were nearly all caught I 40 m. Rock sole were captured 

throughout the ranges of bottom temperatures sampled (9.2-9.90C) and 

were concentrated at 9.4-9.60C. The bottom salinity ranged from 30.3 to 

30.9. Most age-0 rock sole were captured over pure sand. Age-1 rock sole 

were distributed among several sediment types. Rock sole was the only 

flatfish captured on sediment with gravel; four juvenile rock soles were 

captured at a single location with gravel (CS#33). 

Age-0 English sole (Pleuronectes vetulus) were captured at depths 132 m. 

The bottom salinity ranged from 30.3 to 30.6 PSU. Age-0 English sole 

were captured mostly on gravelly sand. 

Distribution of flatfish in relation to depth and substrate type was observed. 

Age-0 flatfishes were most frequently captured at depths ranging from 6-20 m 

and 2 31 m on sand, muddy sand, or gravelly mud substrates. Age-1 flatfishes 

were most frequently captured at depths 2 31 m on muddy sand substrate (Tables 

I and 2). 

The five most abundant juvenile flatfishes collected in Kachemak Bay in 1994 

(age-0 rock sole, flathead sole, Pacific halibut, arrowtooth flounder, and age-1 

yellowfin sole) were identical to the most abundant species in Chiniak Bay, 

Kodiak; however, the percent species composition varied between locations. 

Kachemak Bay had approximately the same proportion of rock sole (43%) and 

flathead sole (36%), whereas Chiniak Bay had 73% rock sole and 11% flathead 

sole. Additionally, when tested against the depth distribution models from 
Table I. Distribution of fla a sh in relation to depth in Kachemak bay, September 1994. 

Depth (m) # stations # age-0 flatfish # age-1 flatfish 

0-5 6 19 18 

6-10 4 210 22 

11-20 5 212 18 

21-30 2 5 3 

3 1-40 4 129 79 

41-50 5 317 138 

5 1-60 6 83 6 1 

61-70 4 79 26 

Total 1053 365 

Table z. Distribution of flatfish in relation to substrate type in Kachemak Bay, September 1994. 

Main sediment # stations # age-0 flatfish # age-1 flatfish 

Boulder 1 0 0 

Cobbly gravel 1 0 0 

Gravel 1 0 4 

Gravelly boulder 1 0 0 

Gravelly mud 1 134 16 

Gravelly muddy sand 5 66 41 

Gravelly sand 2 24 14 

Muddy gravel 1 2 3 

Muddy sand 10 388 235 

Muddy sandy gravel 3 3 4 

Sand 8 434 42 

Sandy mud 1 1 6 

Kodiak (Norcross et al., 1995), some differences were observed for the Kachemak 

Bay collections fiom September 1994. In Kachemak Bay, rock sole were found at 

depths 1 50 m, flathead sole were found at all depths, Pacific halibut were found 

at depths I 40 m, and yellowfin sole were concentrated at stations with depth 

30-60 m. When compared to Kodiak models, all juvenile flatfishes in Kachemak 

Bay were distributed at greater depths. This difference may be due to spatial or 

temporal differences, as Kodiak sampling was conducted in August 1991-94 and 

Kachemak Bay was sampled in late September 1994. Therefore, based on these 

results, a two-year multi-seasonal study is planned to allow determination of 

juvenile flatfish distribution within Kachemak Bay intra-seasonally and intraannually. Future sampling will control for depth in an attempt to isolate the 

controlling factors in juvenile flatfish distribution. Factors that will be investi- 
gated in the future include substrate, temperature, and salinity as analyzed in 

the pilot study. An index of "open" versus "enclosed" bays and associated 

benthos will also be used. 

Preliminary Conclusions 

The goals of this pilot study were to establish that nursery areas for juvenile 

flatfishes do exist in Kachemak Bay, and to characterize the most important 

parameters which define flatfish nursery areas in Kachemak Bay. Results show 

sufficient numbers ofjuvenile flatfish in the studied area, and suggest that 

Kachemak Bay is a nursery area for juvenile flatfishes. The most important 

parameters which define the nursery area are depth and substrate type. Findings 

from Kachemak Bay do not exactly fit the Kodiak models of distribution, as 

flatfish are found deeper in Kachemak Bay. However, these differences may be a 

result of season (sampling in August in Kodiak and September in Kachemak 

Bay) or the unique geomorphology of the two regions. Due to the sediment 

distribution and slope of the continental shelf in Lower Cook Inlet, the geomorphology of Kachemak Bay provides an excellent opportunity to isolate and 

rank the physical parameters that define juvenile distribution for each species of 

flatfish. The proposed two-year study will specifically address this issue. 

From related work (Moles et al., 1994) it has been established that juvenile 

flatfishes are sensitive to oil in the substrate. Because of the potential for additional oil and gas lease development in Lower Cook Inlet, it is imperative to 

have knowledge of nursery areas of juvenile flatfish prior to industry expansion. 

Once the habitat and distribution ofjuvenile flatfish species is known, it will be 

easier to monitor them. Further investigation is required to understand what 

habitats are important to the distribution of juvenile flatfishes in Kachemak Bay. 

This information may be critical to the management of flatfish stocks relating 

to habitat preservation or restoration (Burke et al., 1991), especially in light of 

the impending oil leases. 

Acknowledgments 

The data analysis was conducted by Alisa Abookire and Brenda Holladay. The 

report was written by Alisa Abookire. Field sampling was conducted by Alisa 

Abookire, Franz Miiter, and Me1 Green, while Russ Geagel operated the boat. 

The principal investigator was involved in all phases of the project. 
References 

Berghahn, R. 1986. Determining abundance, distribution and mortality of 0-group 

plaice (Pleuronectesplatessa L.) in the Wadden Sea. J. Appl. Ichthyol. 2: 11-22. 

Burke, J. S., J. M. Miller and D. E. Hoss. 1991. Immigration and settlement 

pattern of Paralichthys dentatus and E! Zethostigma in an estuarine nursery 

ground, North Carolina, U.S.A. Neth. J. Sea Res. 270/4): 393-405. 

Frank, K. T., J. W. Loder, J. E. Carscadden, W. C. Leggett and C. T. Taggart. 

1992. Larval flatfish distributions and drift on the southern Grand Bank 

Can. J. Fish. Aquat. Sci. 49: 467-483. 

Gibson, R. N. 1994. Impact of habitat quality and quantity on the recruitment of 

juvenile flatfishes. Neth. J. Sea Res. 32(2): 191-206. 

Gibson, R. N. and L. Robb. 1992. The relationship between body size, sediment 

grain size and the burying ability of juvenile plaice, PleuronectespZatessa L. J. 

Fish Bio. 40: 71-778. 

Hicks, G. R. F. 1984. Spatio-temporal dynamics of a meiobenthic copepod and 

the impact of predation-disturbance. J. Exp. Mar. Biol. Ecol. 81: 47-72. 

Matarese, A. C., A. W. Kendall, Jr., D. M. Blood and B. M. Vinter. 1989. Laboratory guide to early life history stages of northeast Pacific fishes. NOAA 

Tech. Rep. NMFS 80. 

Minami, T. and M. Tanaka. 1992. Life history cycles in flatfish fi-om the Northwestern Pacific, with particular reference to their early life histories. Neth. J. 

Sea Res. 29(1-3): 35-48. 

Moles, A. and B. L. Norcross. 1995. Sediment preference in juvenile Pacific 

flatfishes. Neth. J. Sea Res. In press. 

Moles, A., S. Rice and B. L. Norcross. 1994. Non-avoidance of hydrocarbon 

laden sediments by juvenile flatfishes. Neth. J. Sea Res. 320/4): 361-367. 

Norcross, B. L., B. A. Holladay and E J. Miiter. 1995. Nursery area characteristics of Pleuronectids in coastal Alaska, U.S.A. Neth. J. Sea Res. In press. 

Pihl, L. and H. W. van der Veer. 1992. Importance of exposure and habitat 

structure for the population density of 0-group plaice, Pleuronectesplatessa L., 

in coastal nursery areas. Neth. J. Sea Res. 29(1-3): 145-152. 

Rogers, S. I. 1992. Environmental factors affecting the distribution of sole (Solea 

solea L.) within a nursery area. Neth. J. Sea Res. 29(1-3): 153-161. 

Tanada, M. 1990. Studies of burying ability in sand and selection to the grain 

size for hatchery-reared marbled sole and Japanese flounder. Nippon Suisan 

Gakkaishi 56: 1543-1548. 

van der Veer, H. W., M. J. N. Bergman, R. Dapper and J. I. J. Witte. 1991. 

Population dynamics of an intertidal 0-group flounder PlatichthysJZesus 

population in the western Wadden Sea. Mar. Ecol. Prog. Ser. 73: 14.1-148. 

Walsh, S. J. 1992. Factors influencing distribution of juvenile yellowtail flounder 

(Limandafe~ru~inea) on the Grand Bank of Newfoundland. Neth. J. Sea Res. 

29(1-3): 193-203. 
Testing Conceptual Models of Marine 

Mammal Trophic Dynamics Using Carbon 

and Nitrogen Stable Isotope Ratios 

Donald M. Schell 

Water Research Center 

Institute of Northern Engineering 

University of Alaska Fairbanks 

Fairbanks, AK 99775 

Abstract 

Steller sea lions and harbor seals are declining in numbers in the northern Guyof 

Alaska and the Bering Sea, and the northern fir seal has apparently stabilized ajer 

a declineporn previously higher numbers. Although no lease sales are currently 

planned in the Bering Sea in the near@ture, feither species is declared endangered, 

oil andgas exploration andproduction might be severely curtailed in the Bering Sea 

or the GulfofAlaska continentalsheyhabitats. This projectficuses on the food web 

dynamics supporting top trophic levels in the GuyofAlaska and the Bering and 

Chukchi Seas with an emphasis on attempting tojnd linkages to explain these 

population declines. The natural abundance stable isotope ratios of carbon and 

nitrogen were used to trace trophic transfers of these elements to identzfipossible 

changes in trophic status or habitat usage over seasonal, annual, and decadal time 

scales. Preliminary data indicates large temporal changes in isotope ratios over the 

seasons which may reject changes in diet and habitat usage. This initial data has 

also shown the presence of large isotopicgradients in zooplankton between the 

continental sheybiota of the Bering and Chukchi Seas versus those_fiom the pelagic 

regions near the Aleutian Islands. The isotopic variations in marine mammal 

tissues showing temporal signals (e.g., whiskers and claws) reveal thatfir seals 

change trophic positions in the food web on a seasonal basis. Little dietary information linked to isotope data is available to account for these changes. Over the next 

year, research will focus on expanding the prey isotope data base and ident@ing 

possible causes for the observed isotopic variations. 

Introduction 

The impetus for this work arises fiom the rapid decline of pinniped populations 

in the Bering Sea and the Gulf of Alaska. In spite of apparent strong correlations 

between the rapid rise of fisheries in the Bering Sea and Gulf of Alaska and 

commercial pressure on herring and pollock stocks, no definitive links or causeand-effect relationships have been established. If the oil and gas industry is going 

to enter the northern Bering Sea or Gulf of Alaska, it is likely to become involved 
in marine mammal and bird concerns. Stable isotope ratio studies, which link 

both energetic and feeding studies as well as provide a means to validate conceptual food web models, are a powerful tool in deciphering both temporal and 

spatial variation in ecosystem energy and nutrient flow. 

From 1984 to 1990, work supported by the Minerals Management Service on 

bowhead whales (Balaena mysticetus) and zooplankton in the Bering and Chukchi 

Seas led to the compilation of a comprehensive data base on the stable isotope 

abundances in the biota. This information led to drastic revision of the perceived 

natural history of bowhead whales and to the assessments of critical habitat for 

bowhead whale feeding. The results of the isotopic work are still being used to set 

model data for recruitment by the species and to test parameters on models being 

employed by the International Whaling Commission. 

Recently the isotopic work has been extended to include sea lions, using a small 

amount of funding by the North Pacific Universities Consortium on Steller Sea 

Lions, to begin analyzing sea lion tissues. As part of the joint U.S./Russian 

ecological investigations of the Bering and Chukchi Seas, additional fish and 

zooplankton samples were collected over much of the study area in summer 1993. 

These samples were analyzed as part of this project. 

Background 

Over the past two decades, stable isotope ratio analysis has emerged as a powerfbl 

tool in ecosystem research both on the process scale and as a validation technique 

for large-scale ecosystem models (Michener and Schell, 1994). In relevant applications to this study, Schell et al. (1~89a) described a geographic gradient in 

isotope ratios in biota across the Alaskan Beaufort Sea and the Bering and 

Chukchi Seas and showed that this gradient could be helpful in describing 

bowhead whale natural history. The Lotopic gradient arises from the primary 

producers in the ecosystem and is passed up food chains to label consumers up to 

the top predators. Saupe et al. (1989) described the parallel shifts in 613C in 

euphausiids and copepods across this region, and Schell et al. (1989b) and Schell 

and Saupe (1993) discussed the effects of the gradient in forming oscillations in 

isotope ratios in whale baleen. Springer et al. (1984,1986) investigated food webs 

in the region and noted the interannual effects of climate on the success of 

seabird recruitment. Hobson and Welch (1992) used isotope ratios to describe the 

trophic relationships of birds and mammals to the available prey species in the 

Canadian Arctic. Further extension to benthos (Dunton et al, 1989) and to fishes 

(Vinette, 1992) has confirmed that the isotopic trends are evident across the entire 

food web. Polar bears residing north of Alaska and Canada in the Beaufort Sea 

are several 9/00 depleted in 13C relative to bears from the western Chukchi Sea 

(Schell and Amstrup, in prep.). 

In contrast to the primarily geographic control on carbon isotope ratios, nitrogen 

isotope ratios are influenced by trophic level. Vinette (1992) has shown that the 
615N of euphausiids and copepods in the Bering, Chukchi, and Beaufort Seas are 

statistically indistinguishable, but when pelagic and benthic species of known 

feeding habits are compared, a predictable enrichment of about 3.3%0 per trophic 

level in 15N occurs. By assembling the trophic spectrum of species within an 

ecosystem it is possible to ascribe trophic status within the ecosystem. Hobson 

and Welch (1992) used 615N values in the Barrow Strait-Lancaster Sound region 

to identify the roles of arctic cod (Boreogadus saida) and other prey species to top 

consumers. Higher trophic levels showed little change in 613C but varied by an 

average of 3.8%0 between levels. Recently, Sease et al. (1993) showed preliminary 

data which confirmed that sea lions occupy a high trophic status in North Pacific 

food webs and reflect a geographic gradient between Prince Wiam Sound and 

the Washington coast. Schell(1996) has further shown that sea lions in the 

Bering Sea are not as high in trophic status as spotted seals and span a wide 

trophic range between individuals. Although a particular sea lion may show 

relatively small isotopic variation over time, among the few individuals sampled, 

very often large differences have been noted. 

Results and Discussion 

Isotope Ratios in Zooplankton 

The analysis of zooplankton samples collected from a Russian ship, RN OKEAN, 

were the initial focus of this study and this aspect of the project was completed 

Figure I. Station locations of WOKEAN, July 20 - September 3,1993. Letters denote areas 

of averaged zooplankton isotope ratio data. Values are shown in Table I. 
during the past year. Figure I represents the cruise track of the vessel. The averaged isotope data for copepods and euphausiids from each of the general test 

areas are listed in Table I. No significant differences were noted between locations 

except for the southern pelagic polygon. Here the 6I3C values were significantly 

more depleted than at other stations for all general taxa tested-euphausiids, 

Table I. Isotope ratio data for euphausiids and copepods collected on the RN OKGSNcmise, July-September 1993 for the 

regions shown in Figure I. Individual data shown for n < 4. 

Euphausiids Copepods 

615N 613C 615N 6I3C 

Region %o 9/00 

A n 4 4 5 5 

avg 9.87 -21.46 9.31 -23.57 

range 9.1 to 11.2 -22.7 to -19.5 8.6 to 10.3 -25.0 to -23.2 

sd 0.72 1.14 0.54 0.85 

B n 4 4 7 7 

a% 6.20 -23.25 4.54 -23.88 

range 5.5 to 6.6 -24.6 to -22.0 3.1 to 6.4 -25.3 to -2.98 

sd 0.43 1.02 1.09 0.75 

C n 2 2 4 4 

a% 8.71 -20.16 7.99 -21.39 

range 8.09,9.32 -19.97, -20.35 7.7 to 8.4 -22.6 to -20.3 

sd 0.26 1 .OO 

D n 9 9 13 13 

avg 8.59 -20.53 9.20 -22.85 

range 7.4 to 9.9 -22.1 to -17.7 6.9 to 13.3 -25.6 to -19.9 

sd 0.83 1.27 1.64 1.52 

E n 1 1 4 4 

a% 8.04 -20.05 8.56 -22.18 

range 7.2 to 9.3 -22.9 to -20.8 

sd 0.59 0.75 

F n 3 3 5 5 

avg 9.38 -20.7 10.83 -22.4 

range 8.4,9.2,10.5 -20.0, -20.0, -22.0 9.2 to 12.0 -23.9 to -20.9 

sd 0.88 1.07 

G n 3 3 3 3 

avg 10.63 -21.5 11.62 -23.4 

range 9.4,10.2,12.3 -20.2, -21.4, -23.0 10.8,11.8 -23.3, -23. 

sd 12.2 -23.4 
copepods, and chaetognaths. This remarkable difference will be looked for again 

in summer 1995 on a research cruise along the Aleutian Islands and into the 

southern Bering Sea. The S1'N and S1'C values were about 2%0 depleted in the 

heavier isotopes when compared to other areas of the Bering Sea. This depletion, 

if typical of areas off the continental shelf in the Bering Sea, may help explain 

some of the sharp oscillations in isotope ratios found along the lengths of whiskers, as described below. 

The possibility of temporal changes in isotope ratios was tested by comparing the 

1993 data against data from earlier collections. Figures 2 and 3 show the S13C and 

S1'N values of copepods and euphausiids from the Bering and Chukchi Seas over 

the sample periods. The region spans the northern Bering Sea on both the 

Russian and U.S. sides. Specific station locations and detailed data for these 

cruises are reported in Schell's (1992) report. No significant differences were found 

except for the southern Bering Sea samples noted above for both S1'C values. 

Although it appears that a trend toward more depleted S13C values is apparent 

over time, this trend is not significant at the p = 0.05 level, and no trends are 

evident in the S1'N data. This indicates that the interannual variations in isotope 

ratios are small within taxa collected from the Bering and southern Chukchi 

Seas. 

SUOO 

SUOl k3 OKs93 

-26 

1987 I 1088 I 1080 I 1000 I 1001 I 1003 I 

Figure 2. Range, average and standard deviations of 613C values of euphausiids and copepods 

collected from the Bering and Chukchi seas. Years of collection are shown beneath each data 

set. Collection dates, station locations and individual data for all cruises prior to 1993 are in 

Schell(1992). 
Copepods 

Figure 3. Range, average and standard deviations of 615N values of euphausiids and copepods 

collected from the Bering and Chukchi seas. Years of collection are shown beneath each data 

set. Collection dates, station locations and individual data are in Schell(1993). 

Isotope Ratios in Marine Mammal iissues 

The collection of samples of marine mammal tissues from native harvests and 

from archived samples has been more successfbl than anticipated. Tables 2 and 3 

list current sample holdings and the status of the preparation and analysis for 

isotope ratios of specimens from the Bering Sea and western Gulf of Alaska, 

respectively. Only a limited portion of the representative data are discussed in this 

interim report. 

The initial examination of the isotope ratios of carbon and nitrogen along the 

lengths of vibrissae from ringed seals, northern fur seals, and Steller sea lions 

revealed that movement across geographic regions with distinct isotope ratios 

resulted in the acquisition of these features by the marine mammals. This data is 

very preliminary at this time and the reasons for their occurrence cannot be 

unequivocally stated. Some of the signal is imparted by geographic effects--the 

primary producer regimes in offshore waters are more depleted in the heavier 

isotopes than those on the continental shelves as evidenced by the isotope ratios 

in herbivores. Figure 4 shows representative isotope ratio traces along vibrissae 

fiom the three marine mammal species tested. Ringed seals fiom the Chukchi 

Sea have the least amount of variation, indicating relatively small temporal 

changes in either overall isotope ratio regimes in the environment or in the 

trophic status of prey species taken. 
Table 2. Pinniped and prey samples from the Bering Sea, 1993-95. 

Species Year N Status 

Northern fur seals (Callorhinus ursinus) 

Northern fur seals (Callorhinus ursinus) 

Steller sea lions (Eumetopias jubatus) 

Steller sea lions (Eumetopias jubatus) 

Steller sea lion (Eumetopias jubatus) 

Steller sea lions (Eumetopias jubatus) 

Ringed seals (Phoca hispida) 

Bearded seals (Erignathus krbatus) 

Walleye pollock (Theragra cbalcogramma) 

Pacific cod (Gadus macrocephalus) 

Capelin (Mallotus villosus) 

Sandlance (Ammodytes hexapterus) 

Squid (Beryteuthis spp.) 

1993 

1994 

1993 

1994 

1994 

1995 

1994 

archived 

1993 

1993 

1993 

1993 

1993 

P = processed (dried and groundcut) 

A = analyzed (isotope ratios) 

R = recorded (data files and plots) 

Table 3. Pinniped and prey samples from the western Gulf of Alaska. 

Species Year N Status 

Steller sea lions (Eumetopias jubatus) 1993 , 10 P, A, R 

Steller sea lions (Eumetopias jubatus) 1994 7 

Harbor seals (Phoca vitulina) 1993 4 P,A,R 

Harbor seals (Phoca vitulina) 1994 10 

Walleye pollock (Theragra chalcogramma) 1993 P, A, R 

Walleye pollock (Theragra chalcogramma) . 1994 P 

Pacific cod (Gadus macrocepbalus) 1993 P,A,R 

Pacific cod (Gadus macrocepbalus) 1994 P 

Herring (Clupeapallasii) 1993 P, A, R 

Hemng (Clupeapalhi;) 1994 P 

Capelin (Mallotus villosus) 1993 P,A,R 

Capelin (Mallofus villosus) 1994 P 

Sandlance (Ammodytes hexapterus) 1993 P,A,R 

Sandlance (Ammodytes bexapterus) 1994 P 

. Squid (Beryteuthis spp.) 1993 P, A, R 

Squid (Boyfeuthis spp.) 1994 P 

P = processed (dried and groundcut) 

A = analyzed (isotope ratios) 

R = recorded (data files and plots) 
1 NFSBI 1 

Figure 4. 6I3C and 615N values from along the lengths of pinniped vibrissae taken from representative animals. Male Steller 

sea lions (top row) and northern fur seals (middle row) were collected from the Pribilof Islands, Alaska, May 1994. Ringed 

seal (bottom row) vibrissae from a female adult (left) and a juvenile (right) were collected from near Barrow, Alaska, July 

1994. 

20 

-19 

-18 

-17 5 

' 

- 

-16 4j 

-15 

-I4 

13 

0 1 2 3 4 5 6 0 1 2 3 4 5 6 

Length - Base to Tip Length - Base to Tip 

-12- 

# -15 r 

- 

-I6- 

-17 

-18- 

-19 

- 20 -12- 

-19 -13- 

- 

-18 -14- 

-17 5 # -15- r .? 

l6 a a -I6- 

- 15 -17- 

-I4 -18- 

-13 -19 

::::r-- - 

F] 

- - 
In contrast, both fur seals and sea lions show pronounced oscillations in isotope 

ratios along vibrissae, indicating changes in either diet or location or both, over 

the temporal span represented by the length of the whiskers. The fur seals show 

isotope ratio variations characterized by regular oscillations at constant intervals 

along the lengths accompanied by much larger singular shifts in 6"ILThese 

oscillations may be greater than 8%0 (Figure 4). Some fur seds fiom the Pribilof 

Islands showed very high 615N values at the tips of: the vibrissae followed by a 

decline in the more recently laid down tissue. The 613C oscillations, although 

usually matching the 615N changes in direction, are typically much smaller in 

magnitude. The implications of a relatively constant 613C are that the 615N 

changes arise from shifts in diet and not fiom migratory movements to areas of 

differing isotopic regimes. 

Sea lions show widely varying values in isotope ratios along vibrissae (Figure 4). 

Some animals were found to have only one or two large variations (up to 6-8%0), 

whereas others had several smaller oscillations. Growth rates of these whiskers 

were not available to date the times that the changes occurred; however, experiments with captive sea lions currently ongoing at the University of British 

Columbia should provide us with these essential data. For this project, whiskers 

of captive animals were marked at varying lengths and the growth rates are 

periodically measured. Similar experiments are planned for captive fur seals at the 

Mystic Marine Life Aquarium in Connecticut. 

Potential prey species also showed large isotope ratio variations depending on size 

and location of capture (data not shown). Pollock shift trophic levels as they 

increase in size and predation by marine mammals on these changing size classes 

will be reflected in the isotope ratios of tissues being laid down at that time. The 

specific correlations between predator and prey isotope ratios have not yet been 

made but are being tested as data from past cruises and current analyses become 

available. 

Conclusions 

Although the data shown are very preliminary at this stage, several tentative 

conclusions have been postulated for further testing. These include: 

I) Isotope ratios in zooplankton fiom the Bering Sea indicate that primary 

producers in pelagic waters have lower 613C and 815N values than samples 

collected fiom onshelf and continental slope waters. This difference, if 

persistent across seasons and years, may offer a useful marker for habitat 

usage by marine mammals. 

2) Northern fur seals show marked regular oscillations in 615N along the 

lengths of their vibrissae but not nearly to the same extent in 613C, 

suggesting that they undergo major shifts in trophic position on a seasonal 

or interannual basis. 
3) Steller sea lions also show oscillations in carbon and nitrogen isotope 

ratios but the 615N values are usually higher than those of fur seals. This 

may indicate a trophic separation between the species, but data is insufficient at this time to draw any final conclusions. 

References 

Dunton, K. H., S. M. Saupe, A. N. Golikov, D. M. Schell and S. V. Schonberg. 

1989. Trophic relationships and isotopic gradients among arctic and subarctic 

marine fauna. Mar. Ecol. Prog. Ser. 56: 89-97. 

Hobson, K. A. and H. Welch. 1992. Determination of trophic relationships 

within a high arctic marine food web using 613C and 615N analysis. Mar. 

Ecol. Prog. Ser. 84: 9-18. 

Michener, R. H. and D. M. Schell. 1994. The use of stable isotopes in tracing 

marine aquatic food webs, p. 138-157. In R. Michener and K. Ljatha [eds.], 

Stable isotopes in ecology. Blackwell. 

Saupe, S. M., D. M. Schell and W. B. Griffiths. 1989. Carbon-isotope ratio 

gradients in western arctic zooplankton. Mar. Biol. 103: 427 138-157432. 

Schell, D. M. 1992. Stable isotope analysis of 1987-1991 zooplankton samples 

and bowhead whale tissues. Final report to Minerals Management Service 

OCS study MMS-92-0020. 

Schell, D. M. 1996. Stable isotope ratios in Alaskan marine fauna: Application 

to pinniped trophic dynamics. Mar. Mammal Sci. In press. 

Schell, D. M. and S. C. Amstrup. In prep. Separation of polar bear stocks using 

stable isotope ratios: Applications to western arctic stocks. 

Schell, D. M. and S. M. Saupe. 1993. Feeding and growth as indicated by stable 

isotopes, p. 491-506. In J. J. Burns, J. J. Montague and C. J. Cowles [eds.], 

The bowhead whale. Men Press. 

Schell, D. M., S. M. Saupe and N. Haubenstock 1989a. Natural isotope abundances in bowhead whale (Balaena mysticetu;) baleen: Markers of aging and 

habitat usage, p. 260-269. In I? Rundel, J. Ehleringer and K. Nagy [eds.], 

Stable isotopes in ecological research. Springer-Verlag. 

Schell, D. M., S. M. Saupe and N. Haubenstock 1989b. Bowhead whale 

(Balaena mysticetu;) growth and feeding as estimated by techniques. Mar. 

Biol. 103: 433-443. 

Sease, J. L., K. A. Hobson, J. M. Strick, R. L. Merrick and J. Piatt. 1993. Stable 

isotope studies of Steller sea lions and other Alaska pinnipeds. (abstract). 

Tenth biennial conference on the biology of marine mammals. Galveston, 

TX, November 1993. 

Springer, A. M., D. G. Roseneau, D. S. Lloyd, C. P. McRoy and E. C. Murphy. 

1986. Seabird responses to fluctuating prey abundance in the eastern Bering 

Sea. Mar. Ecol. Prog. Ser. 32: 1-12. 

Circulation on the North Central Chukchi 

Sea Shelf 

Thomas J. Weingartner 

Institute of Marine Science 

University of Alaska 

Fairbanks, AK 99775 

Abstract 

The circulation on the north central Chukchi Sea shelfand its connection to other 

portions of this shelfarepoorly known. Indeed, existing circdation scenarios dger 

sign$?cant+J;om one another in this regard This report summarizes a mooring 

deployment program in the north central Chukchi Sea designed to resolve these 

issues. Spec$?c goals of this program are to determine: I) the mean and time-varying 

circulation and water mass property distribution of the region and 2) the extent to 

which local winds, forcing by the deep ocean along the sheFreak, anger buoyancy 

fix contribute to circulation variability. The results have direct bearing on understanding transport pathways in the Chukchi Sea and on verzyjting models which 

predict the dispersal ofpollutants (e.g., hydrocarbons, trace metah, radionuclides) 

released anuor advected into the region. The north central shelfis biologically 

important insofar as it supports a large benthic biomass and large numbers of 

marine mammals which feed on the benthos. As several of the processes under study 

are not unique to the Chukchi Sea, it is anticipated that the results will have 

applications to other arctic shelves. 

Three moorings were deployed on the north centralshelfof the Chukchi Sea between 

Herald and Hanna Shoals. These moorings are complemented by simultaneous 

current meter measurements obtainedfiom Bering Strait, Hope Sea Valley, and the 

northeast Chukchi Sea (ofshore of Pt. Lay to Bawow Canyon), fallshipboard 

hydrographic surveys, and daily satellite imagery of the sea-iceJ;eld throughout the 

winter months. The existing mooring and hydrography components of the program 

are supported by the National Science Foundation (NSF), the Ofice of Naval 

Research (ONR), and the Japan Marine Science and Technology Center 

(JAMSTEC). All of the moorings were scheduled for recovery in September 1995. 

The remote sensing component of the program will be conducted by collaborating 

NationalAeronautics and Space Administration (NASA) colleagues. A portion of 

the results are expected to serve as a basis for comparison with numerical model 

experiments for the understanding of outJZows of dense bottom water formed on 

arctic shelves in winter. 
Introduction 

The Chukchi Sea is unique among arctic shelf seas in that its circulation and 

physical properties are strongly influenced by waters of Pacific Ocean origin. Due 

to the mean pressure gradient between the Pacific and Arctic Oceans, these 

waters flow northward through Bering Strait and ultimately enter the Arctic 

Ocean. En route, they are modified by a variety of exchanges with the atmosphere, sea-ice, and bottom sediments. Both the inflow and these exchanges have 

a profound influence on the circulation and dispersal of pollutants potentially 

introduced onto this shelf. For reference, Figure I shows a regional bathymetric 

map which includes the location of the current meter moorings referred to later. 

The figure shows that while much of this shelf is relatively flat, there are a 

number of key geomorphic features which exert significant influence on the 

circulation and, implicitly, on the various water mass modification processes. 

These features include Bering Strait in the southern Chukchi Sea, Barrow 

Canyon in the northeast corner of the shelf, and Herald Valley in the northwest. 

Other important features include Hope Sea Valley, a broad depression extending 

fiom Bering Strait to Herald Valley, Herald Shoal in the central basin, and 

Hanna Shoal in the northeast. 

Figure I. Bathymetric Map of the Chukchi Sea. Solid circles indicate positions of current 

meter moorings deployed in September 1994. Moorings C1, C2, and C3 are supported by 

MMS-CMI. Station positions (marked by plus signs) used to construct the contour plots are 

shown in Figure 3. 
Although considerable effort has been expended in the last decade to understand 

the oceanography of this shelf, several fundamental issues remain which have 

direct bearing on pollutant dispersal. The most important of these issues, and the 

objective of this program, concerns the nature of both the mean and time-varying 

circulation field on the outer shelf. Coachman et al. (1975) presented one of the 

earliest regional circulation scenarios (Figure 2) which suggested that north of 

Bering Strait the flow bifurcates. One branch, consisting primarily of highsalinity, nutrient- and carbon-rich water (Bering Shelf Water, or BSW, following 

the nomenclature of Coachman et al., 1975; Walsh et al., 1989), flows northwestward from Bering Strait through the Hope Sea Valley and Herald Valley (beyond 

which the path of this water is a subject of speculation). The other branch, 

% ...,.. ..:. 

+,, 

- Variable "Cores" (various positions) 

62" - - 62" 

Depth in meters 

I I I I I I I I 

Figure 2. Near-bottom circulation of Chukchi Sea as inferred by Coachman et al. (1975). 

[Figure copied fiom Coachman et al., 19751 

99 -- 
Herald Vallev 

consisting of more dilute and nutrient- and carbon-depauperate water, flows 

northeastward parallel to the Alaskan coast within the Alaska Coastal Current 

(ACC). The ACC enters the Arctic Ocean and the outer shelf of the Beaufort 

Sea through Barrow Canyon. 

While the branched nature of the flow is well established, recent measurements 

(Weingartner, in prep.) indicate that there is, in fact, a third branch that flows 

northward parallel to the east flank of Herald Shoal-not southward (Figure 2) 

as inferred by Coachman et al. (1975). This third branch also consists of BSW as 

indicated in Figure 3. This figure shows plots of temperature, salinity, dissolved 

oxygen, and fluorescence (proportional to chlorophyll) contoured from data 

collected along an east to west hydrographic transect occupied in September 1992 

between Barrow Canyon and Herald Valley (Figure I). Relatively warm (> 3.0°C), 

low-salinity (<32.2) water with a high dissolved oxygen concentration (>7.0 mL L-l) 

and low fluorescence characterizes the ACC waters entering Barrow Canyon. In 

contrast, bottom water salinities are higher and temperatures colder in Herald 

Herald Valley Test Plot 

Barrow Canvon Herald Vallev Barrow Canvon 

0 100 200 300 400 500 600 0 100 200 300 400 500 600 

Distance along Transect (km) 

Figure 3. Contour plots of temperature (upper left), salinity (upper right), dissolved oxygen (lower left) and fluorescence 

(lower right) between Herald Valley and Barrow Canyon along the hydrographic transect shown in Figure I. Data collected 

in September 1992. 
Valley. Fluorescence levels are also substantially higher here and near-bottom 

concentrations of oxygen are low ((6.0 mL LT1). Near-bottom concentrations of 

nutrients are substantially greater in Herald Valley than in Barrow Canyon (not 

shown). AU of these properties indicate that the water flowing through Herald 

Valley is the BSW water mass. The third branch is indicated by the prominent 

fluorescence signature over the gentle depression to the east of Herald Shoal 

where bottom water properties are also consistent with the BSW water mass. 

Data from stations to the south occupied on this same cruise shows that these 

water mass characteristics extend southward to the southern Chukchi Sea and 

Bering Strait. In fact, their properties indicate that they were formed from water 

masses advected from the deep Bering Sea basin. The existence of the branch 

along Herald Shoal is also verified by moored current measurements. Mean 

monthly velocity vectors fiom four current meter moorings deployed in the 

Chukchi Sea in 1991-92 are shown in Figure 4. Of particular interest are the 

vectors for mooring HS3 which was situated in the depression east of Herald 

Shoal. The remaining moorings all lie within the ACC (MBC12, UBC12 were 

- 25 :, 0.0 1 \ / I // - / ' . 70°N 165"W 

E -2.5 

5.0 

65"N 170"W 

-2.5 - E -5.0 

,- 

-7.5 

15.0 

8m77---7 

- 

:, 10.0- 

5.0 - 6 0.0 I 

5.0 - 

- 10.0 

5.0 '1: 2IJBcl2 0 5.0 

-10.0 

- 15.0 - 

& 10.0- 

5.0 - 6 0.0 \. I\\ I 1 I\ \ HS3 

5.0 - 

E3 ! , , , , , , . . cL,3 

0 0.0 

OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG MEAN 

1991 1992 

Figure 4. Mean monthly ocean current and wind velocity vectors between October 1991 and 

August-September 1992. Mooring CLE3 was located offshore of Cape Lisburne, moorings 

UBCl2 and MBCl2 were located in Barrow Canyon, and HS3 was located to the east of 

Herald Shoal at the position indicated by C1 in Figure I. Corresponding mean monthly wind 

velocity vectors at 65W, 170%' and 70W, 165%' are indicated in the upper two time series 

plots. 
located in Barrow Canyon and CLE3 was located offshore of Cape Lisburne). 

The vectors for HS3 show northward flow in all months, even when strong 

northeasterly winds produce a reversal or nearly stagnant flow in the coastal 

current. The annual average implies a northward transport of about 2 x lo5 m s-~, 

about 25% of the mean northward transport through Bering Strait (Roach et al., 

1995). Because BSW carries a high load of organic carbon, this northward flow 

could be a significant source of carbon for the outer shelf. Indeed, it might be 

essential in sustaining the large benthic biomass observed here (Feder et al., 1994) 

and the marine mammals which feed on these organisms. (Fay, 1982; Moore and 

Clarke, 1986). 

A fundamental goal of this program is to determine where this water flows once 

it is transported north of Herald Shoal. In the absence of significant wind 

forcing, dynamical considerations suggest that the flow would be eastward, and 

very limited current measurements (Johnson, 1989) indicate steady (subsurface) 

eastward flow northwest of Hanna Shoal even when subject to strong easterly 

winds. Circulation on the outer shelf might also be forced by the pressure gradient associated with the eastward flowing Beaufort Undercurrent (Aagaard, 1984). 

In contrast, winter sea-ice trajectories are westward under the prevailing northeasterly winds (Colony and Thorndike, 1984; Muench et al., 1991), although it is 

not clear if ice drift is a reliable proxy for subsurface circulation. As a consequence 

of these conflicting and limited observations it is not at all clear what the circulation field over the north central shelf is. This proposal hypothesized that the 

(subsurface) flow along the outer shelfis eastward and includes BSW advected 

along the east flank of Herald Shoal and a portion of the transport carried 

through Herald Valley. If a mean eastward circulation prevails, then this flow 

represents a pathway for pollutants discharged onto the Russian shelves to the 

west or northward from the southern Chukchi Sea. Regarding the former, East 

Siberian Sea waters are believed to flow eastward around the north coast of 

Wrangel Island and are known to flow southeastward in the Siberian Coastal 

Current (Coachman et al., 1~75) which enters the Chukchi Sea through Long 

Strait (Figure I). To date, nearly all of the oil exploration activity in the Chukchi 

Sea has occurred in the region north and east of Herald Shoal. However, additional lease sales are under consideration in both the Russian and U.S. Economic 

Exclusion Zones of Hope Sea Valley. Consequently, pollutants released in this 

region could be carried onto the north central shelf. If, on the other hand, the 

prevailing flow is westward, then pollutants from marine industrial activities in 

the Beaufort Sea could be advected into this region. 

In addition to determining the regional mean flow and water properties, an 

important program goal is to characterize the temporal flow variability. Three 

mechanisms can be identified which would contribute to this variability: winds, 

low-frequency oscillations propagating along the shellbreak, and thermohaline 

influences. Winds, which play a prominent role in the circulation of the Chukchi 
Sea including Bering Strait, explain a significant fraction of the current variance 

(Coachman and Aagaard, 1988; Weingartner, in prep.). However, given Johnson's 

(I&) observations it is not clear that their influence will be as prominent over 

the outer shelf. Here, we might find that a significant fraction of the flow variability is related to remotely forced shelfwaves propagating along the continental 

slope as Aagaard and Roach (1990) maintain to be the case on the outer Beaufort 

shelf. An important issue pertinent to modeling considerations is to determine 

the extent to which current variability is coherent with the local wind field. For 

example, if local winds and current variations are incoherent, then regional winddriven barotropic models are unlikely to provide accurate circulation forecasts. 

Thermohaline (or buoyancy) effects might also be quite important in this shelf's 

dynamics. The primary focus of this program is on the effects of negative buoyancy forcing associated with brine rejected from growing sea-ice. Particularly 

strong thermohaline gradients, which result in strong baroclinic pressure gradients, are associated with coastal polynyas (Schumacher et al., 1983). In the northeast Chukchi Sea, the prevailing northeasterly winds of winter frequently effect 

an offshore drift of ice leading to the development of a large polynya system 

along the Alaskan coast and concomitant formation of large volumes of cold, 

saline (dense) water (Cavalieri and Martin, 1994). Gravitational spreading, 

bottom friction, alongshore convergence within the coastal current (Weingartner, 

in prep.) and/or instabilities associated with the density front formed along the 

perimeter of the polynya (Gawarkiewicz and Chapman, 1995) can force this 

dense, coastal water mass offshore and across the north central Chukchi Sea. All 

of these effects could lead to a midwinter flow regime which is markedly different 

from the other months of the year. An illustration of one possible manifestation 

of this thermohaline effect is seen in Figure 5, which shows time series of temperature and salinity between October 1993 and September 1994 from two current 

meter moorings located near mooring C1 and C2 (see Figure I). The winter of 

1994 is characterized by two month-long events during which very high salinity 

water (at the fi-eezing point) is observed at this location. The rapid increase and 

decrease in salinity at the end and the beginning of each of these events suggest a 

fiont or eddy propagating through the region. The depth of the feature is probably about 10 m and it is believed that the dense water originated fiom the 

polynyas along the northwest coast of Alaska-some 200 krn to the east of the 

mooring site. This data suggests that the circulation on the north central shelf 

might, to some extent, be influenced by nearshore processes occurring several 

hundred kilometers to the east. 

From the pollution transport perspective, the significance of these plumes is that 

they represent a mechanism by which shelfpollutants can be trapped within a 

near-bottom layer and advected across the shelfinto the deeper portions of the 

Arctic basin. As presently configured, existing pollutant transport models do not 

incorporate these thermohaline effects. This transport mechanism is suggested in 
35.0 - 

34.5 - 

34.0 - 

0 33.5 - .- c 33.0 - .- - a 32.5 - 

(1) 32.0 - 

31.5 - 

31.0 - 

30.5 - 

3.0 - 

2.0 - 

1.0- e o.o I ,r 

-1.0-- - 

-2.0 - 

35.5 -. 

35.0 - 

34.5 - 

34.0 - 

E 33.5 - .- 33.0 - 2 32.5 - 

32.0 - 31.5 - 

31.0 - 

30.5 - 

4.0 

3.0 

A 2.0 

2 1.0 

0.0 

-1 .o 

-2.0 

1 31 30 30 29 28 30 29 29 28 28 27 26 

OCT NOV DEC JAN FEE MAR APR MAY JUN JUL AUG 

1991 1992 

Figure 5. Time series of temperature and salinity between October 1993 and September 1994 from two moorings located in 

the central Chukchi Sea. With respect to Figure I, the mooring positions were approximately at C1 (bottom two time 

series) and C2 (top two time series). 

Figure 6, which shows contours of temperature, salinity, and silica along a hydrographic section extending across the shelf and slope northeastward of Hanna 

Shoal. (The data were collected fi-om the ONR-funded U.S. Coast Guard Polar 

Star cruise of August of 1993). A near-bottom plume of very cold (-1.7"C) water 

(highlighted by shading in Figure 6) is seen descending from the shelf to a depth 

of about 125 m. Over the shelf, the plume is separated from the surface by a 

strongly stratified pycnocline which inhibits vertical mixing. The high silica 

values associated with the plume imply that this is the BSW mass. This observation also provides evidence for an eastward subsurface drift along the outer shelf. 

The low temperatures and the salinities (-32.5) are characteristic of water formed 

on the Chukchi shelf in winter. The salinity data in Figure 5 suggests that, in 

winter, plumes or eddies of substantially greater salinity (density) can be formed 

and subsequently swept into the basin to penetrate to even greater depths. 
. 

Salinity 

0 50 100 150 200 250 

Distance along Transect (krn) 

Figure 6. Contour plots of temperature (top), salinity (middle), and dissolved silicate (bottom). 

Data were collected in August 1993 from the USCG Polar Star along a transect extending 

northeastward from Hanna Shoal. 
Findy, an ancillary goal of this program is to provide better documentation of 

interannual variability in the oceanography of the Chukchi Sea. Substantial 

progress has been made toward this goal with respect to understanding the 

variability in water transport through the Bering Strait (Roach et al., 1995). 

However, little is known about long-term variability over the remainder of the 

Chukchi shelf. For example, in comparing current meter data from 1991-92 

(Weingartner et al., in prep.) with measurements made in 1986-87 (Aagaard and 

Roach, 1990) and 1981-82 (Aagaard, 1988), it appears that from spring through 

fall, flow within the ACC was similar in all these years. In contrast, the winter 

circulation differed significantly among these years. In the winter of 1991-92 the 

coastal flow reversed or remained stagnant for several months, while relatively 

steady flow was observed in 1981-82 and only a brief flow reversal occurred in 

January 1986. As another example, local alongshore winds were significantly 

coherent with current variations in Barrow Canyon in the winter of 1991-92, 

consistent with the response of a coastal current to alongshore winds. However, in 

1986-87 current variations here were only weakly correlated with the local winds. 

This result plus other evidence led Aagaard and Roach (1990) to conclude that 

current variations were due to remotely-forced shelfwaves with periods of about 

five days. Comparison of late fall-early winter spectra of the alongshore winds 

between these two years shows nearly twice as much energy in 1986-87 at periods 

between four and six days. Shelfwave amplitudes are expected to differ accordingly between the two years as a result. Finally, it was noted that in each of these 

winters the size and the persistence of the coastal polynyas (hence the volume of 

dense water formed and the strength of the buoyant forcing) were substantially 

different fiom one another. Given this variability and the few available data sets, 

it is impossible to determine which, if any, of these winters is typical. 

The results of this project have a direct bearing on a number of CMI Framework 

Issues: 

I) They will address mechanisms pertaining to the transport and fate of 

pollutants stemming from offshore marine activity in the Chukchi Sea or 

advected fiom elsewhere, including Russian waters andlor the Beaufort 

Sea; 

2) The hypothesized circulation might dXer significantly from that predicted 

by existing barotropic, wind-driven circulation models (Observations are 

therefore required to verify these models andlor to guide modelers on the 

additional physics required to produce realistic simulations. Existing 

pollutant transport models do not include the effects of buoyancy or deepocean forcing along the shelf7slope margin.); 

3) The central shelf of the Chukchi Sea appears to be important to bottomfeeding marine mammals which might therefore be impacted by pollutants via the food chain; and 
4) Conclusions pertaining to the potential impact of marine industrial 

activity must be based on an appreciation of the inherent variability of the 

physical environment. 

Discussion 

This CMI program complements moorings supported by NSF, ONR, and 

JAMSTEC. (The NSF and ONR programs are being conducted in collaboration 

with Knut Aagaard of the University of Washington). The moorings were 

deployed in the fall of 1994 and were scheduled for recovery in September 1995 

&om the University of Alaska's RNAlpha Helix. Figure I shows the mooring 

positions, and Table I details the mooring particulars. The array is concentrated in 

the northeast Chukchi Sea but also includes moorings in the Bering Strait and 

Hope Sea Valley. It is designed to examine the circulation field between Herald 

Table I. Locations of Current Meter Moorings Deployed in September 1994. (The MMS-CMI moorings are indicated as 

C1, C2, and C3 in Figure I and in the table.) 

Area Latitude Longitude Bottom Depth Funding Agency 

(N) (W) (4 

Central Chukchi Sea 70" 37' 167" 5' 54 MMS1 (Cl) 

71" 20' 164" 27' 46 MMS1 (C2) 

71" 41' 167O11' 49 MMS1 (C3) 

69" 59' 166" 14' 46 ONR1 

70" 45 ' 163" 17' 46 ONR1 

Upper Barrow Canyon 71" 4' 159" 29' 79 JAMSTECZ 

71'3' 159" 32' 76 NSF 

Middle Barrow Canyon 71'25' 157" 45' 120 NSP 

71°21' 157" 37' 107 NSF-JAMSTEC4 

71" 15' 157"31' 62 NSF-ONR1 

Hope Sea Vdey 68" 10' 168" 58' 56 NSF1 

Eastern Bering Strait 65" 47' 168" 35' 54 NSF 

'Each mooring consists of an Aanderaa current meter (ACM) moored above a Seabird temperature/conductivity recorder 

(Seacat). The instruments are vertically separated by 1 meter with the Seacats located 6 meters above the seabed. 

'One Acoustic Doppler Current Profile (ADCP) current meter with a Seacat 6 m above bottom. The ADCP collects 

current profiles averaged over 2 meter bins throughout the water column from a depth of 60 m to 12 m 

Two Seacat/ACM pairs: 7 and 25 meters above bottom. 

4Four Seacat/ACM pairs: 7,25,40, and 60 meters above bottom. 
and Hanna Shoals and the connection to the flow over the north central shelf 

and the Alaska Coastal Current (including Barrow Canyon). During the cruises 

hydrographic surveys throughout the Chukchi Sea (supported by JAMSTEC and 

NSF) are also conducted that allowed determination of regional water mass 

characteristics using temperature, salinity, dissolved oxygen, nutrients and 6018. 

Lee Cooper is performing the 6018 analyses with support from the Department 

of Energy. 

Planned Analyses 

The data will be analyzed with the goal of addressing the hypotheses advanced in 

the proposal. These are: 

I) The mean flow of subsurface waters on the outer shelfis eastward and 

consists of BSW, mixed with other Chukchi Sea water masses, flowing 

northward through Herald Valley and along the east flank of Herald 

Shoal. 

2) In winter, some of the dense water formed within the coastal polynyas 

athwart the northwest Alaskan coast, spreads northwest into the central 

Chukchi Sea. 

Included within the specifics of these hypotheses are: 

a) The determination of the mean and time-varying subsurface circulation 

on the north central shelf; and 

b) The determination of the spatial coherence of the current variations and 

their relation to wind and buoyancy forcing. 

The data fiom the three CMI moorings will be analyzed in conjunction with 

those from moorings funded by the other agencies participating in this program. 

Where possible, comparisons will be made between these data and results fiom 

previous years. The approach to addressing hypothesis 2 relies on understanding 

the wind and thermohaline forcing on the Chukchi shelf. This will be addressed 

using SSMA (Special Sensor MicrowaveAmager) imagery (to be analyzed by D. 

Cavalieri at NASA's Goddard Space Flight Center), winds derived fiom surface 

pressure forecast fields, and meteorological data fiom Barrow. Determining the 

mean flow, its variability, and the relationship between flow and water property 

variations to the various forcing mechanisms will be addressed using standard 

statistical and time-series analysis techniques. The methods given by Cavalieri 

and Martin (1994) and Weingartner et al. (in prep.) will be used to analyze the 

satellite imagery and to compute heat and salt fluxes and the buoyant forcing. 

Evidence of eastward propagating shelf waves will be sought by examining the 

coherence and phase relationship between the CMI moorings and the Barrow 

Canyon moorings which are located about 250 krn to the east. There has been a 

collaboration with Glen Gawarkiewicz and Dave Chapman of the Woods Hole 

Oceanographic Institution within the past year concerning the physics of dense 
water outflows on arctic shelves in general and those of the Chukchi Sea in I 

! 

particular. They have received funding from NSF to continue dense water modeling studies with a focus on conditions representative of the Chukchi shelf. I 

Consequently, this CMI program effectively represents one leg of a coordinated 

observational, modeling, and remote sensing program directed toward a better 

understanding of winter arctic shelf circulation processes. 

References 

Aagaard, K. 1984. The Beaufort Undercurrent, p. 47-71. In I? Barnes and E. 

Reimnitz [eds.], The Alaskan Beaufort Sea: Ecosystems and environment. 

Academic. 

Aagaard, K. 1988. Current, CTD, and pressure measurements in possible 

dispersal regions of the Chukchi Sea. Anchorage, AK. USDOC, NOAA, and 

USDOI, MMS. Outer Continental Shelf Environmental Assessment 

Program Final Reports to Principal Investigators 57: 255-333. 

Aagaard, K. and A. T. Roach. 1990. Arctic Ocean-shelfexchange: Measurements in Barrow Canyon. J. Geophys. Res. 95: 18163-18175. 

Cavalieri, D. J. and S. Martin. 1994. The contribution of Alaskan, Siberian, and 

Canadian coastal polynyas to the cold halocline layer of the Arctic Ocean. J. 

Geophys. Res. 99: 18343-18362. 

Coachman, L. K. and K. Aagaard. 1988. Transports through Bering Strait: 

Annual and interannual variability. J. Geophys. Res. 93: 15535-15540. 

Coachman, L. K., K. Aagaard and R. B. Tripp. 1975. Bering Strait: The regional 

physical oceanography. Univ. Washington Press. 

Colony, R. and A. S. Thorndike. 1984. An estimate of the mean field of arctic 

sea ice motion. J. Geophys. Res. 89: 10623-10629. 

Fay, F. H. 1982. Ecology and biology of the Pacific walrus, Odobenus rosmarus 

divergens Illiger. North America Fauna 74. U.S. Dept. Interior, Fish Wildl. 

Serv. 

Feder, H. F., A. S. Naidu, S. C. Jewett, J. M. Hameedi, W. R. Johnson and T. E. 

Whitledge. 1994. The Northeastern Chukchi Sea: Benthos-environmental 

interactions. I. Benthic community structure. Mar. Ecol. Prog. Ser. 111: 171- 

190. 

Gawarkiewicz, G. and D. C. Chapman. 1995. A numerical study of dense water 

formation and transport on a shallow, sloping continental shelf. J. Geophys. 

Res. 100: 4489-4508. 

Johnson, W. R. 1989. Current response to wind in the Chukchi Sea: A regional 

coastal upwelling event. J. Geophys. Res. 94: 2057-2064. 

Moore, S. E. and J. T. Clarke. 1986. A comparison of gray whale (Eschrichtius 

robustus) and bowhead whale (Balaena mysticetus) distribution, abundance, 
habitat preference and behavior in the northeastern Chukchi Sea, 1982-84. 

Rep. Intl. Whal. Comm. 36: 273-279. 

Muench, R. D., C. H. Pease and S. A. Salo. 1991. Oceanographic and meteorological effects on autumn sea-ice distribution in the western Arctic. Ann. 

Glaciol. 15: 171-177. 

Roach, A. T., K. Aagaard, C. H. Pease, S. A. Salo, T. Weingartner, V. Pavlov and 

M. Kulakov. 1995. Direct measurements of transport and water properties 

through Bering Strait. J. Geophys. Res. 100: 18433-18458. 

Schumacher, J. D., K. Aagaard, C. H. Pease and R. B. Tripp. 1983. Effects of a 

shelfpolynya on flow and water properties in the northern Bering Sea. J. 

Geophys. Res. 88: 2723-2732. 

Walsh, J. J., C. P. McRoy, L. K. Coachman, J. J. Goering, J. J. Nihoul, T. E. 

Whitledge,T. H. Blackburn, A. M. Springer, R. D. Tripp, D. A. Hansell, S. 

Djenidi, E. Deleersnijder, K. Henriksen, B. A. Lund, I? Andersen, F. E. 

Miiller-Karger and K. K. Dean. 1989. Carbon and nitrogen cycling within 

the BeringKhukchi Seas: Source regions for organic matter effecting AOU 

demands of the Arctic Ocean. Progr. Oceanogr. 22: 277-359. 

Weingartner, T. J., D. J. Cavalieri and J. Groves. In prep. Circulation and water 

mass modification on the northeast Chukchi Sea shelf. 
Winter Circulation Processes in the 

Northeast Chukchi Sea 

Thomas J. Weingartner 

Institute of Marine Science 

University of Alaska 

Fairbanks, AK 99775 

Abstract 

Cross-shelfadvection of dense water, formed as a result of salt rejectionj-om 

growing sea-ice, might provide an efective mechanism by which pollutants are 

conjned to the bottom and advected into the deep basin of the Arctic Ocean. Recent 

modeling eforts have contributed sign$icantly towards understanding this process, 

but there are few direct observations available for comparison with the models. In 

the northeast Chukchi Sea dense water is formed in winter in the coastalpolynyas 

adjacent to the Alaskan coast andjows through Barrow Canyon. A helicopter-based 

jeldprogram was attempted in March 1995 to obtain a suite of conductivitytemperature-depth (CTD)projlesj-om Barrow Canyon in order to determine the 

spatial structure and mixing history of a dense ouvow. The data were to be compared with the model reszrlts. Unfortunately, poor weather limited the number of 

sampling days, and the project goals were not attained. 

Introduction 

Winter oceanographic conditions on arctic shelf seas are profoundly influenced 

by the thermohaline effects associated with freezing and ice production. Salt is 

rejected from growing sea ice and increases the salinity (density) of the underlying seawater. Over shallow shelves, horizontal gradients in ice production and salt 

rejection result in the formation of a bottom layer of cold, saline water (dense 

plume). Such conditions are met on a number of arctic shelves, in particular on 

the Chukchi shelf(Cava1ieri and Martin, 1994; Martin and Cavalieri, 1989). Here, 

the prevailing northeasterly winter winds form a system of polynyas along the 

northwest coast of Alaska. Large volumes of ice and salt are formed in these 

relatively narrow (5-30 krn wide) features. Although the physics governing plume 

behavior are not well known, the plumes have important implications on shelf 

circulation and mixing and therefore on the dispersal of pollutants. For example, 

because they are strongly stratified, vertical mixing across the plume boundary is 

inhibited, hence pollutants incorporated into the plume are confined within a 

bottom layer. The horizontal density gradient provides a source of energy for flow 

instabilities and eddies (Gawarkiewicz and Chapman, 1995; Jiang and Garwood, 

1995; Whitehead, 1993). Under the influence of gravity, the plumes and the eddies 

tend to flow downslope, i.e., along the bottom and across the shelf/slope margin. 
The dense water will sink along the continental slope, possibly mixing with 

ambient seawater en route, until it reaches a depth where the plume density 

equals that of the ambient seawater. At this depth, sinking ceases and horizontal 

spreading of the plume ensues. 

Although this description glosses over a number of complicated issues, it illustrates the potential that this thermohaline process has for concentrating pollutants near the bottom and advecting them across the shelfbreak As currently 

constructed, existing pollution transport models are primarily wind-driven and 

barotropic and therefore do not incorporate thermohaline physics. Moreover, the 

thermohaline models described above are based upon a number of assumptions 

and simplifications and consequently, the results need to be verified by winter 

observations. These have been difficult to obtain due to the logistical difficulties 

involved in conducting winter field campaigns in the arctic. This program sought 

to obtain a suite of measurements for model comparison by conducting a winter 

conductivity-temperature-depth (CTD) survey in Barrow Canyon on the northeast Chukchi shelf (Figure I). The effort was geared toward determining the 

water mass properties, mixing potential, and spatial scales of dense shelfwater 

I. Bathymetric Map of Barrow Canyon and vicinity. Solid circles indicate positions of 

current meter moorings deployed in September 1994, and solid triangles indicate positions of 

CTD stations occupied between March 7 and March 10,1995. 
flowing through Barrow Canyon. The source of these dense plumes are the 

coastal polynyas of the northeast Chukchi Sea. Most of the flow on the northeast 

portion of the shelfdrains through Barrow Canyon into the Arctic Ocean and 

over the outer shelfof the Beaufort Sea (Coachman et al., 1975). Dense plumes 

have previously been observed flowing down the canyon in middle and late 

winter (Aagaard et al., 1985; Weingartner et al., in prep.). These dense water 

outflows can last for one to two months. Furthermore, the density of the plumes 

was such that they were capable of descending to the bottom of the Canadian 

Basin if no mixing occurred between the plume and the ambient shelf/slope 

water. Theoretical arguments show that the mixing is a function of the density 

contrast between the plume and ambient shelfwater and the magnitude of the 

bottom slope (Price and Barringer, 1994; Pratt, 1986). In particular, if the bottom 

slope magnitude exceeds -3 x then the plume should begin to entrain 

ambient water. In agreement with this theory, Weingartner et al. showed that the 

plume undergoes virtually no mixing over the upper portion of Barrow Canyon 

where the bottom slope is -7 x They further hypothesized that if mixing 

occurs within the canyon, then it is initiated in the lower half of the canyon at 

about the position of the 200 m isobath. The objective of this program was to test 

this hypothesis by occupying a set of cross-canyon CTD transects along the axis 

of the canyon. Additional goals of the program included determining: 

I) The spatial structure of the dense water flowing off the Chukchi shelf and 

through Barrow Canyon; and 

2) The change in plume volume and density as it flows along the length of 

the canyon. 

Measurements satisfying both objectives would be directly comparable with 

predictions made by the models and would therefore provide a means for verification. The CTD survey was complemented by an array of current meter moorings 

deployed in the canyon. The particulars of the moorings are indicated in Table I 

and their positions are shown in Figure I. The moorings, supported by the 

National Science Foundation (NSF), the Office of Naval Research (ONR), and 

the Japan Marine Science and Technology Center (JAMSTEC) were all deployed in the fall of 1994 and were scheduled for recovery in fall 1995. The current 

meters collect hourly measurements of velocity, temperature, and salinity, and 

allow the CTD measurements to be interpreted within the context of the temporal and spatial evolution of the flow and density fields. Specifically, the moorings 

at the head of the canyon will provide information on the properties of the plume 

as it enters the canyon. The moorings deployed midway down the canyon will 

allow a determination of the extent to which mixing has altered the plume 

properties as it flows down the canyon. Both sets of moorings would provide 

information on the spatial structure of the dense water, although not at the spatial 

resolution of the CTD survey. Three cross-canyon CTD transects were planned: 

at the head of the canyon, midway down the canyon, and at the mouth of the 
Table I. Locations of Current Meter Moorings Deployed in Barrow Canyon in September 1994. 

Area Latitude Longitude Bottom Depth Funding Agency 

(N) (W) (m> 

Upper Barrow Canyon 71" 4' 159" 29' 79 JAMSTEC1 

71" 3' 159" 32' 76 NSF"? 

Middle Barrow Canyon 71" 25' 157" 45' 120 NSF3 

71'21' 157" 37' 107 NSF-JAMSTEC3 

'One Acoustic Doppler Current Profile (ADCP) current meter with a Seacat 6 m above bottom. The ADCP collects 

current profiles averaged over 2 meter bins throughout the water column from a depth of 60 m to 12 m. 

'Two Seacat/ACM pairs: 7 and 25 meters above bottom. 

3Four SeacadACM pairs: 7,25,40, and 60 meters above bottom. 

4Mooring consists of an Aanderaa current meter (ACM) moored above a Seabird temperature/conductivity recorder 

(Seacat). The instruments are vertically separated by 1 meter with the Seacats located 6 meters above the seabed. 

canyon. The first two transects were established in regions where the bottom 

slope was less than the critical value, while the bottom slope at the mouth of the 

canyon exceeds the critical value. 

Results and Discussion 

Field operations were conducted fiom an aluminum hut built by the Department 

of Search and Rescue of the North Slope Borough. The Borough's Search and 

Rescue helicopter airfieighted (via sling load) the hut with all the sampling and 

survival gear from the Barrow airport to the sampling sites. Unfortunately, 

inclement weather within the three-week time fiame scheduled severely impeded 

our ability to conduct this survey. Ground blizzards, fog, and unseasonably low 

temperatures prevailed throughout the survey period, resulting in unsafe flying 

conditions. A further complication arose due to the heavily ridged nature of the 

ice which necessitated deviations fiom the planned station locations in order to 

find a broad and stable enough first-year ice floe upon which to work. As a 

consequence, only four of the approximately 30 stations planned were occupied. 

The position of these stations is indicated in Figure I, and their position and 

sampling times are listed in Table 2. 

While only four stations were occupied, the sampling was conducted safely, 

efficiently, and without any substantial problems. The sampling plan required all 

the gear and scientists to be airlifted to the site from Barrow. The helicopter 

would then depart after setting down the field team and return when requested to 

move the team to the next site. At each location a Iondiameter hole was drilled 
Table 2. Locations and Times of CTD stations occupied in Barrow Canyon. 

Station Number Date Time Latitude Longitude Bottom Depth 

1995 (GMT) (N) (w) (m) 

1 March 7 0335 71 15.75 157 36.8 66 

2 March 7 2136 71 18.7 157 38.7 93 

3 March 10 2106 71 20.7 157 42.2 104 

4 March 11 0135 71 24.7 157 42.1 120 

through the ice. A wall tent was erected over the hole with one end joined to the 

hut. The tent's ridgepole served as a mount for a block and the CTD was lowered 

through the ice hole using a line that ran through the block. The opposite end of 

this line was wound around the drum of an electric winch bolted to the floor of 

the hut. Heat to the hut and tent was generated from electric heaters and 

Coleman stoves. In addition, the hut contained all necessary winter survival gear 

and housed the electronics for a VHF radio, fathometers, and global positioning 

system. Electrical systems were powered by a 6.5 kilowatt portable generator. 

Critical to successfU1 sampling was the ability to maintain above-fieezing temperatures in the hut and wall tent so that neither the CTD nor the water samples 

collected in Niskin bottles froze during any phase of the operation. In particular, 

fieezing of the CTD would lead to spurious data and possible damage to the 

conductivity cell. 

The use of the hut made this task easy and allowed very efficient use of the time 

spent on the ice. The lowest ambient air temperature encountered during this 

project was -33"F, and hut and wall tent temperatures were easily maintained 

between 45" and 60°F throughout this time. In fact, it is believed that the sampling design would have easily permitted operations at ambient air temperatures 

to at least -50°E 

Because of the weather, sampling could not be performed in a synoptic fashionthere were delays of several days between occupation of the first and last station. 

Sampling commenced on March 7, following the cessation of several days of 

strong northeasterly winds which opened a wide polynya offshore of Barrow. 

However, dense fog and strong northeasterly winds (30 knots) prevented safe 

operations on March 8 and 9. Wind conditions on March 10 were calm but 

temperatures had decreased to about -35°F' the approximate cutoff temperature 

for the Borough's helicopter. These wind changes most likely resulted in significant changes in the water mass property distribution over the transect. Thus it is 

difficult to interpret the results in the absence of the current meter data. Nevertheless the salinity data is plotted in Figure 2. Temperatures were at the fieezing 

point throughout the water column and the salinities (which ranged between 

31.7 and 32.5) were characteristic of the dominant winter water mass mode on 
0 2 4 6 8 10 12 14 16 

Distance along Transect (krn) 

z. Contour plot of salinity across Barrow Canyon. The perspective is looking 

downcanyon with the westmost station (4) on the left side of the plot. 

the Chukchi shelf. There is no evidence in this data of water upwelled into the 

canyon fi-om the Atlantic layer of the Arctic Ocean, as occasionally happens. At 

approximately 95 m depth within the canyon there is a 20 m thick halocline, 

across which salinities increase by about 0.5. The data shows a doming of the 

isohalines centered on station 3, but it is suspected that this is an artifact due to 

the time delay in sampling at stations 2 and 3. The downward inclination in the 

halocline from east to west (between stations 3 and 4) is thought to be real. The 

tilt of the isohalines between these two stations implies that the geostrophic 

component of the along-canyon velocity component increases with height above 

the bottom. Although verification of this interpretation must await the current 

meter results, this interpretation does corroborate one result from Gawarkiewicz 

and Chapman (199s) who found a similar tilt in the isohalines associated with 

downcanyon flow of a dense plume. 
Acknowledgements 

Although the goals of this program were not achieved, many individuals and 

entities contributed considerable effort to the project and deserve recognition. 

This program would not have been possible without the approval of Mayor 

George Ahmagoak who, on behalf of the residents of the North Slope Borough, 

approved the participation of the Borough and enthusiastically supported the 

science goals. This is a level of support by a municipal body which is believed to 

be unparalleled in oceanography. The Department of Search and Rescue should 

also be acknowledged for their support, which included helicopter logistics, the 

warm indoor facility necessary for the project work and gear storage, and the 

sampling hut. Chuck Caldwell (Director, Search and Rescue) designed the hut 

and assisted in numerous ways during our stay. Gordon Hutton, Jim Martin, 

Charles Stalker, and he piloted the helicopter during the field program. Richard 

Lord and Dave Knowles were the crew chiefs responsible for the sling load 

operation. We appreciate the expertise involved by the pilots and crews in the 

potentially hazardous slinging operation. The crew chiefs, along with Dan and 

Eli Bryant, assisted with various operations on the ground. In addition, the 

Department of Wildlife Management provided lodging in their Animal Research 

Facility and the use of a wall tent and miscellaneous equipment which defrayed 

costs and contributed to a safe and efficient operation. In particular, Craig George 

and Robert Suydam are thanked for their help in this regard. Craig George 

provided much advice and participated in the field operations on two occasions. 

Jens Leavitt kept an attentive lookout for polar bears and cheerfully assisted in all 

phases of the fieldwork Richard Glenn of Barrow Technical Services provided 

advice on ice conditions and assistance in hiring a polar bear guard. Steve Sweet 

of the Institute of Marine Science assisted in Fairbanks throughout all phases of 

the program. Finally, John Smithhisler's tireless attention to all details contributed to a safe and reliable program. 

References 

Aagaard, K., J. H. Swift and E. C. Carmack 1985. Thermohaline circulation in 

the arctic mediterranean seas. J. Geophys. Res. 90: 4833-4846. 

Cavalieri, D. J. and S. Martin. 1994. The contribution of Alaskan, Siberian, and 

Canadian coastal polynyas to the cold halocline layer of the Arctic Ocean. J. 

Geophys. Res. 99: 18343-18362. 

Coachman, L. K., K. Aagaard and R. B. Tripp. 1975. Bering Strait: The regional 

physical oceanography, Univ. Washington Press. 

Gawarkiewicz, G. and D. C. Chapman. 1995. A numerical study of dense water 

formation and transport on a shallow, sloping continental shelf. J. Geophys. 

Res. 100: 4489-4508. 
Jiang, L. and R. W. Garwood, Jr. 1995. A numerical study of three dimensional 

dense bottom plumes on a southern ocean continental slope. J. Geophys. Res. 

Martin, S. and D. J. Cavalieri. 1989. Contributions of the Siberian shelfpolynyas 

to the Arctic Ocean intermediate and deep water. J. Geophys. Res. 94: 12725- 

12738. 

Pratt, L. J. 1986. Hydraulic control of sill flow with bottom friction. J. Phys. 

Oceanogr. 16: 1970-1980. 

Price, J. F. and M. 0. Barringer. 1994. Outflows and deep water production by 

marginal seas. Prog. Oceanog. 33: 161-200. 

Weingartner, T. J., D. J. Cavalieri and J. Groves. In prep. Circulation and water 

mass modification on the northeast Chukchi Sea shelf. 

Whitehead, J. A. 1993. A laboratory model of cooling over the continental shelf. 

J. Phys. Oceanogr. 23: 2412-2427. 
New Projects 

Two new CMI projects are being funded this fiscal year, along with the ongoing 

projects reported above. They are presented here so that the reader is aware of the 

latest work supported by the CMI. 

The Alaska Frozen Tissue Collection and Associated Electronic Database: i 

A Resource for Marine Biotechnology I 

Gordon H. Jarrell 

University of Alaska Museum 

University of Alaska Fairbanks 

Fairbanks, AK 99775-6960 

Abstract 

The Alaska Frozen Tissue Collection (AFTC) is theprimary regional archive for 

j-ozen zoological samples and a major contributor to biotechnology studies ofAaska 

and its waters. Advances in molecular biology are rapidly establishing the value of 

j-ozen specimens for detecting environmental change. Samples in the AFTC are 

essential for monitoring long-term trends in marine organisms. Though new 

material is acquiredfiom several sources, important opportunities have been missed 

an4 unfortunately, some investigators are still unaware of this resource. The 

objective of this proj'ect is to expand the AFTC's zoologicalscope of marine organisms and thereby establish the AFTC as a state-finded regional resource for monitoring long-term trends in Alaska's marine environment. The AFTC is also 

expanding collaborative eforts with the Alaska Marine Mammal Tissue Archival 

Prq'ect (AMMZXP) and other marine mammalprojects throughout the state. 

Suppor+om the CMI will do three things: 

I) Expand the scope of the collection by recruiting contributions of marine 

mammal, birdjsh, and invertebrate specimensj-om Cook Inlet, Shelikof 

Strait, and the Beaufort and Chukchi Seas. Specimens that are preserved 

now will be important baseline samfles as analyses become more sophisticated and as environmentalpertzsrbation increases. 

2) Develop an electronic database that is accessible through the internet, thus 

facilitating the transfer of information and sharing genetic resources among 

investigators. 

3) Secure the AFTC Collection Coordinator as a permanen t state-finded 

position thus insuring a long-term systematic record of marine populations 

in Alaska's marine ecosystems. 

Hypotheses directly relevant to the Mineral Management Service? needs are now 

being tested with AFTC specimens. Two lettersj-om researchers received since the 

submission of the originalproposal demonstrate the potential of this resource for 
addressing important management questions. The genetic status of harbor seals is 

directly relevant to their uncertain protection status. That study has a far better 

chance of achieving sign$icant results because of the availability ofAFTC specimens. AFTC specimens are also being used to test several hypotheses concerning 

northern sea lions. Both of these species have evidenced steep population declines and 

their future management willjpre importantly in the development ofAlaska's 

oflore and coastal resources. 

Interaction Between Marine Humic Matter and Polycyclic Aromatic 

Hydrocarbons in Lower Cook Inlet and Port Valdez, Alaska 

David G. Shaw 

Institute of Marine Science 

University of Alaska Fairbanks 

Fairbanks, AK 99775-7220 

Abstract 

Humic materials are a major component of naturally occurring organic matter 

which interact strongly with organic pollutants includingpolycyclic aromatic 

hydrocarbons (PAH). The resulting chemical associations injuence the fate and 

efects ofpollutants in the marine environment. While these factors are becoming 

increasingly appreciated by the environmentalscience and environmental management communities, there is insu$cient understanding ofhow this interaction occurs 

or how changes in the chemical characteristics of humic matter injuence its ability to 

interact withpollutants. This proposal suggests a project to provide such information 

directly applicable to Lower Cook Inlet and Port Yaldez, Alaska. Spec@cally, this 

project willstatistically examine the relationship between variations in the amount 

and chemical characteristics of humic acidpom marine sediments with the concentrations of a suite of PAHpom those same sediments. Measurements and interpretation will be coordinated with two other CMI-findedprojects (S. Henrichs andJ 

Braddoc2, principal investigators) which are studying sediment sorption of PAH 

and microbial degradation of PAH, respectively. 
Funding Summary 

Student Support 

The Cooperative Agreement specifically stressed the need for supporting education along with research. The following student support information is summarized for the ten projects presently supported by the Coastal Marine Institute 

(CMI) : 

Funds from MMS Match from other sources 

Fiscal Year 94 

7 Master Students 

2 Doctoral Students 

Source Totals 

Fiscal Year 95 

7 Master Students 

4 Doctoral Students 

Source Totals 

Totals to Date 

These data show a strong and growing commitment to the education of graduate 

students by the projects supported though the CMI. 

Total CMI Funding 

The total MMS funding available for funding CMI projects through federal 

fiscal year 1995 is approximately $2 million. Since all CMI-funded projects 

require a one-to-one match with non-federal monies, the total project commitment for this time period has been approximately $4 million. 

Sources of Matching 

Matching for the CMI-funded projects has come from a wide variety of sources. 

It was originally thought that it would be difficult to obtain $1 million per year in 

matching to support CMI research. Identifying and ver+ng sources remains a 

major administrative problem in the development of the CMI proposals, but it is 

clear that match is available for those investigators who are willing to spend the 

necessary extra effort locating and securing the support. The following list of 
"matching support" participants are presented to demonstrate the breadth of 

support that has been located: 

Afognak Native Corporation 

Alaska Department of Fish and Game (ADF&G) 

Alyeska Pipeline Service Company 

British Petroleum Exploration (BPX) 

College of Natural Sciences, University of Alaska Fairbanks (UAF) 

Institute of Arctic Biology, UAF 

Institute of Marine Science, UAF 

Japanese Marine Science and Technology Center (JAMSTEC) 

Kodiak Island Borough 

North Slope Borough 

University of Alaska Fairbanks, Equipment Fund 

University of Alaska Museum, UAF 

University of Northern Iowa 

Water Research Center, UAF 

Some of the CMI-funded projects are closely related to other federally funded 

projects which cannot be considered as match, but nevertheless augment and 

expand the value of a project. Related projects are funded by the National Science 

Foundation (NSF), the Office of Naval Research (ONR), the National Aeronautics and Space Administration (NASA), and the National Marine Fisheries 

Service (NMFS). 

A positive relationship has continued to develop between MMS, the University 

of Alaska, and the State of Alaska since the formation of the CMI. All parties to 

the agreement as well as the residents of Alaska are expected to benefit from the 

cooperative research that has been and continues to be funded through the 

cooperative CMI effort.