Sensitivity to Hydrocarbons and Baselines of Exposure 

in Marine Birds on the Chukchi and Beaufort Seas

Principal Investigator: Tuula Hollmén1,2

Graduate Student: Ann Riddle1,2

1College of Fisheries and Ocean Sciences, University of Alaska Fairbanks 

2Alaska SeaLife Center

FINAL REPORT 

OCS Study BOEM 2016-064 

October 2016
Contact Information:

email: CMI@alaska.edu

phone: 907.474.6782 

fax: 907.474.7204 

Coastal Marine Institute 

School of Fisheries and Ocean Sciences 

University of Alaska Fairbanks

P. O. Box 757220 

Fairbanks, AK 99775-7220 

This study was funded in part by the U.S. Department of the Interior, Bureau of Ocean Energy Management (BOEM) through 

Cooperative Agreement M13AC00005 between BOEM, Alaska Outer Continental Shelf Region, and the University of Alaska 

Fairbanks. This report, OCS Study BOEM 2016-064, is available through the Coastal Marine Institute, select federal depository 

libraries and http://www.boem.gov/Environmental-Stewardship/Environmental-Studies/Alaska-Region/Index.aspx 

The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the 

opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement 

by the U.S. Government.
ii

TABLE OF CONTENTS

LIST OF FIGURES ..................................................................................................................................... iv

LIST OF TABLES........................................................................................................................................ v

ABSTRACT................................................................................................................................................. vi

INTRODUCTION. ....................................................................................................................................... 1

OBJECTIVES............................................................................................................................................... 3

METHODS ................................................................................................................................................... 3

Selection of Species..................................................................................................................................... 3

Current CYP1A Activity........................................................................................................................... 4

Field samples ............................................................................................................................... 4

Liver EROD assay ....................................................................................................................... 5

Sensitivity to Hydrocarbon Exposure ....................................................................................................... 6

Source material............................................................................................................................. 6

Egg development ......................................................................................................................... 6

Hepatocyte cell extraction ........................................................................................................... 6

Cell culture QA/QC ..................................................................................................................... 7

Cell culture assays ....................................................................................................................... 7

Analytical Techniques............................................................................................................................... 8

Curve fitting ................................................................................................................................. 8

Sensitivity assessment ................................................................................................................. 9

RESULTS ..................................................................................................................................................... 9

Current CYP1A Activity........................................................................................................................... 9

Liver collections........................................................................................................................... 9

Microsome EROD ........................................................................................................................ 9

Hydrocarbon Sensitivity ......................................................................................................................... 11

Source material........................................................................................................................... 11

Cell culture assays...................................................................................................................... 12

Analysis................................................................................................................................................... 21

Curve fitting................................................................................................................................ 21

DISCUSSION............................................................................................................................................. 25

Field Collections..................................................................................................................................... 25
iii

CYP1A Activity...................................................................................................................................... 28

Hydrocarbon Sensitivity ......................................................................................................................... 29

CONCLUSIONS......................................................................................................................................... 29

ACKNOWLEDGEMENTS:....................................................................................................................... 30

STUDY PRODUCTS. ................................................................................................................................ 31

REFERENCES ........................................................................................................................................... 33

APPENDICES ............................................................................................................................................ 36

A: Number of EROD assays performed for species/dose combinations....................................36

B: CPE results by species/dose combination .............................................................................39

C: Statistical analysis of EROD results for DMSO and ethanol controls..................................46

D: Project images.......................................................................................................................48
iv

LIST OF FIGURES

Figure 1: Pre- and post- breeding liver sample collection areas. .................................................................. 4

Figure 2: EROD responses in Steller’s eider to different concentrations of chrysene doses with 24-hour 

dose exposure.............................................................................................................................................. 14

Figure 3: EROD responses in Steller’s eider to different concentrations of BNF doses with 24-hour dose 

exposure...................................................................................................................................................... 14

Figure 4: EROD responses in Steller’s eider to different concentrations of phenanthrene doses with 24-

hour dose exposure. .................................................................................................................................... 15

Figure 5: EROD responses to different amount of neat Alaska North Slope crude oil dose and cell control 

with 24-hour dose exposure in Steller’s eider............................................................................................. 15

Figure 6: EROD responses to different amount of media diluted Alaska North Slope crude oil dose and 

cell and media control with 24-hour dose exposure in Steller’s eider........................................................ 16

Figure 7: EROD responses to different amount of DMSO diluted Alaska North Slope crude oil doses and

cell and media control with 24-hour dose exposure in Steller’s eider........................................................ 16

Figure 8: EROD responses in Steller’s eider to 1.0 μM chrysene dose with 12-, 24-, and 36-hour dose 

exposure...................................................................................................................................................... 17

Figure 9: EROD responses in tufted puffin to different concentrations of chrysene doses with 24-hour 

dose exposure.............................................................................................................................................. 17

Figure 10: EROD responses in tufted puffin to different concentrations of BNF doses with 24-hour dose 

exposure...................................................................................................................................................... 18

Figure 11: EROD responses in ten marine bird species and mallard control to 1.0 μM chrysene dose with 

24-hour dose exposure. ............................................................................................................................... 18

Figure 12: EROD responses in six marine bird species and mallard control to 1.0 μM BNF dose with 24-

hour dose exposure. .................................................................................................................................... 19

Figure 13: EROD responses to 1.0 μL neat Alaska North Slope crude oil dose with 24-hour dose exposure 

in five target species and one control species............................................................................................. 19

Figure 14: EROD responses to 5.0 μL neat Alaska North Slope crude oil dose with 24-hour dose exposure 

in four target species and one control species............................................................................................. 20

Figure 15: Statistical analysis of Steller’s eider EROD results with assay time in minutes....................... 21

Figure 16: Statistical analysis of Steller’s eider oil EROD results with assay time in minutes.................. 22

Figure 17: Statistical analysis of tested species EROD results to different amount of neat Alaska North 

Slope crude oil ............................................................................................................................................ 23

Figure 18: Statistical analysis of tested species EROD results to different amount of Alaska North Slope 

crude oil dissolved in carrier reagent dimethyl sulfoxide (DMSO)............................................................ 23

Figure 19: Statistical analysis of tested species EROD results to different amount of media diluted Alaska 

North Slope crude oil.................................................................................................................................. 24

Figure 20: Statistical analysis of tested species EROD results to different amount of BNF ...................... 24

Figure 21: Statistical analysis of tested species EROD results to different amount of chrysene................ 25
v

Figure 22: Hunters outside their cars hunting flocking eiders near Barrow, AK, August 2015 ................. 26

Figure 23: Slicing a greater white-fronted goose liver for sampling .......................................................... 26

Figure 24: Processing a greater white-fronted goose in a snow blind near Barrow, AK, May 2015.......... 27

Figure 25: Common murre liver cell culture with red blood cell contamination before (A) and after (B) 

washing with phosphate-buffered saline (PBS).......................................................................................... 29

LIST OF TABLES

Table 1: Cytopathic effects (CPE) measurements ........................................................................................ 8

Table 2: Birds collected during pre- and post-breeding hunts over the course of this project...................... 9

Table 3: Median EROD results (pmol/min/mg protein) with sample size by species, season, and time vial 

was frozen post-mortem for all collected liver samples.............................................................................. 10

Table 4: Median EROD results (pmol/min/mg protein) with sample size by species, season, and time vial 

was frozen post-mortem for duplicate microsome extraction QA/QC ....................................................... 11

Table 5: Median EROD results (pmol/min/mg protein) for 10-minute post-mortem samples (2014 postbreeding) from freezer storage experiment................................................................................................. 11
vi

ABSTRACT

With prospects of increasing development of oil and gas resources in the Chukchi and Beaufort 

Seas, the establishment of baselines and assessment of the sensitivity of arctic biota to 

hydrocarbon exposure provide key information needed for management and conservation of 

natural resources potentially impacted by development. Baseline exposure data can inform future 

monitoring of avian population health, and provide a metric for evaluating the success of 

remediation efforts, should they occur. Identification of sensitive species and populations can 

inform resource management, risk assessment of new development activities, and development 

of long-term monitoring strategies. We evaluated baselines of hydrocarbon exposure in select 

avian species of subsistence importance (king eider, common eider, and greater white-fronted 

goose) in the Chukchi and Beaufort Seas by measuring liver cytochrome P450 (CYP1A) activity. 

Results from this study provide the first assessment of baselines for hydrocarbon exposure in 

these species and form a basis for development of field programs for monitoring exposure levels 

in marine birds in the Chukchi and Beaufort Sea region. We also evaluated sensitivity to 

hydrocarbons in a broader suite of marine bird species using species-specific cell culture 

methods. These species offer a spectrum of candidate bioindicators of conservation and 

subsistence importance and included spectacled eider, Steller's eider, king eider, common eider, 

long-tailed duck, greater white-fronted goose, black brant, and three species of alcids. Liver cell 

culture sensitivity and CYP1A activity results from this project provide valuable tools and 

information for monitoring Arctic bird populations, identifying sensitive species, and planning 

future assessments in the event of an oil spill.
1

INTRODUCTION

A rich variety of marine bird species use the coastal habitats along the Chukchi and Beaufort 

Seas during their Arctic pre-breeding, breeding, and post-breeding seasons. These species 

represent multiple taxonomic groups, including marine-associated waterfowl (sea ducks, geese), 

alcids, loons, and shorebirds. The region supports a large number of migratory birds; the 

nearshore zone is a key migration corridor for many arctic-breeding species, and the marine 

waters provide key staging areas during spring and fall migration. Additionally, many of these 

species use the coastal tundra and nearshore barrier islands for nesting and brood/chick rearing, 

spending several months of their annual cycle in the Chukchi and Beaufort Seas and adjacent 

coastal habitats. 

The coastal communities of the region rely on marine resources for subsistence, including

several species of sea ducks and geese. King eiders (Somateria spectabilis) are the most 

abundant and most commonly hunted sea duck species, but common eiders (Somateria 

mollissima) and long-tailed ducks (Clangula hyemali) are used as well. Greater white-fronted 

goose (Anser albifrons), black brant (Branta bernicla), and Canada goose (Branta canadensis)

are hunted in the region, with greater white-fronted goose the most frequently harvested by 

hunters (Robert Sarren, personal communication, June 10, 2014).

Documented population declines of several marine bird species have been identified as a 

conservation concern. The spectacled eider (Somateria fischeri) and the Steller’s eider 

(Polysticta stelleri) are listed as threatened under the US Endangered Species Act due to 

significant population declines (Federal Register 1993, 1997). Population numbers of both king 

and common eiders are believed to be down by half compared to historical levels (Suydam et al. 

2000), and long-tailed duck populations have declined (Hollmén et al. 2003 and references 

therein). The yellow-billed loon (Gavia adamsii), a species of conservation concern, is also 

found in the region (Earnst et al. 2005). Reasons for these population declines are not well 

understood.

Arctic birds may be exposed to a variety of harmful contaminates in the Arctic and during life 

stages spent away from the Arctic (i.e., migration or on wintering grounds). For example, 

elevated, and potentially detrimental, levels of mercury exposure have been recorded in Arcticbreeding shorebirds (Perkins et al. 2016). Waterfowl are also at risk for lead poisoning by 

consuming lead shot left on the tundra or ponds on hunting grounds (Flint et al. 1997, Wilson et 

al. 2004). Male spectacled eiders wintering off of St. Lawrence Island, Alaska, had elevated 

levels copper, cadmium, and selenium, which may decrease fecundity or survival of young 

(Trust et al. 2000b). With prospects of resource development in the Chukchi and Beaufort Seas

region, understanding current exposure levels and sensitivity to hydrocarbons is essential to 

inform monitoring and protection of these potentially vulnerable and culturally important marine 

bird populations.
2

Due to post-ingestion metabolism by the host, direct measurement of oil constituents in bird 

tissues cannot be used to assess exposure to polycyclic aromatic hydrocarbons (PAH) (Lee et al. 

1985). Instead, cytochrome P450 (CYP1A) enzyme induction has been used as a biomarker of 

hydrocarbon exposure in wildlife, including marine waterfowl (Trust et al. 2000a, Miles et al. 

2007, Esler 2008, Esler et al. 2010). CYP1A is induced by exposure to PAH constituents of 

crude oil, and analysis of liver 7-ethoxyresorufin-O-deethylase (EROD) activity has been used as 

an indicator of CYP1A induction. EROD activity measures the catalytic function of 

hydrocarbon-inducible CYP1A and is a standard and widely used measurement for assessing 

exposure to hydrocarbons from oil. Previous field and captive studies have linked increased 

EROD activity to oil exposure in harlequin ducks (Histrionicus histrionicus), Steller’s eider, and 

Barrow’s goldeneye (Bucephala islandica) (Trust et al. 2000a, Miles et al. 2007, Esler 2008, 

Esler et al. 2010). However, systematic baseline assessments of CYP1A induction in marine 

birds of the Chukchi and Beaufort Seas have not been reported to date.

Similarly, assessment of the sensitivity of marine birds of the Chukchi and Beaufort Seas to 

hydrocarbon exposure has not been systematically conducted. Understanding the comparative 

sensitivity of marine birds of the region would be valuable in identifying suitable candidate 

species for long-term monitoring and in assessing relative risks hydrocarbon exposure poses to 

the arctic biota. Recent advances in cell culture techniques provide analytical tools to 

characterize species-specific sensitivity and responses to hydrocarbon exposure. These 

techniques utilize species-specific liver cell lines and a suite of reference compounds, under 

controlled laboratory conditions, to test unique species-specific responses and enable 

comparisons among species. Measurement of EROD activity in liver cultures allows for speciesspecific assessment of magnitude and duration of CYP1A induction. In addition, EROD results 

can be combined with other measurements of cellular or genetic effects, allowing us to evaluate 

for potential cellular or genetic pathology associated with hydrocarbon exposure and CYP1A 

induction. Cell culture techniques, and specifically avian hepatocyte cell culture, have been used 

for a variety of purposes including investigations into possible injury or damage from toxic 

substances (Brendler-Schwaab et al. 1994, Kennedy et al. 1996, Hollmén et al. 2008–2012). For 

example, Kennedy et al. (1996) used CYP1A induction in hepatocyte cell cultures, measured by 

EROD activity, to predict the sensitivity of chickens, pheasants, turkeys, ducks, and herring gulls 

to several hydrocarbons. 

In summary, this project established baselines for hydrocarbon exposure in marine waterfowl in 

the Chukchi and Beaufort Seas region. Species used in the study are important for local 

subsistence activities and represent a variety of potential exposure pathways due to differences in 

life history and habitat use. Measures of baseline exposure provide valuable background 

information for assessing future exposure levels. Additionally, using recently developed 

laboratory cell culture techniques, a broad suite of candidate species were screened for their 

sensitivity to hydrocarbon exposure. Results from these studies will help guide identification and 

selection of suitable priority species for monitoring marine birds for hydrocarbon exposure, 
3

based on feasibility of field sampling and sensitivity of species. A better understanding of 

sensitivity among species will also provide information about relative risks of exposure to the 

arctic biota.

OBJECTIVES

1. Assess baseline levels of current CYP1A activity in selected marine bird indicator species 

of the Chukchi and Beaufort Seas.

2. Assess comparative sensitivity to hydrocarbon exposure in selected marine bird indicator 

species of the Chukchi and Beaufort Seas.

METHODS

Selection of Species

The criteria used to select candidate species for this study included population status, subsistence 

use, and role as a potential bioindicator in coastal marine areas as well as sampling logistics and

feasibility for use in long-term of monitoring. We used common eider, king eider, and greater 

white-fronted goose for the baseline assessments. The Chukchi and Beaufort Seas and adjacent 

terrestrial and nearshore areas provide important habitat for these species (Suydam et al. 2000, 

Dickson and Gilchrist 2002, Oppel et al. 2008), and all three are important resources for 

subsistence and game hunters in the region. Population declines have been noted in king eider 

and common eider populations in the Beaufort Sea (Suydam et al. 2000). Due to differences in 

habitat use and foraging strategies, eiders and geese have the potential to serve as indicators of 

the at-sea benthic environment and more terrestrial/near shore environments, respectively.

We broadened the species selection included in laboratory sensitivity studies by adding Steller’s 

eider (Polysticta stelleri), spectacled eider (Somateria fischeri), long-tailed duck (Clangula 

hyemali), black brant (Branta bernicla), common murre (Uria aalge), tufted puffin (Fratercula 

cirrhata), black guillemot (Cepphus grylle), and surrogate pigeon guillemot (Cepphus columba).

We also planned to used mallard (Anas platyrhunchos) and chicken (Gallus domesticus) cell 

lines as a reference for the results from the marine birds of interest. These species were selected 

based on their conservation status, subsistence use, and potential to serve as bioindicators of 

different components of the aquatic environment and different exposure pathways. Due to 

significant population declines, the spectacled eider and the Alaska-breeding Steller’s eiders are 

listed as threatened under the US Endangered Species Act (Federal Register 1993, 1997). Longtailed duck populations are considered a species of concern due to population declines (Hollmén 

et al. 2003 and references therein). Both long-tailed ducks and black brant are used for 

subsistence by the arctic coastal communities, and black brant represents a goose species with a 

strong marine association. Due to their different foraging ecology (piscivorous vs. benthic 

foraging), alcids have the potential to serve as bioindicators for different components of the 

aquatic food web and exposure pathways.
4

Current CYP1A Activity

Field samples

Liver samples to measure hydrocarbon-inducible CYP1A activity were collected in collaboration 

with the North Slope Borough Department of Wildlife Management. Samples were collected 

opportunistically from hunter-killed birds and from lethal take during spring (pre-breeding) and 

fall (post-breeding) seasonal hunts near Barrow, AK, over three years (Figure 1). Our goal was to 

collect up to 20 liver samples per season/year/species from the three target species: king eider, 

common eider, and greater white-fronted goose. Eider samples were collected during fall hunts 

and greater white-fronted goose samples were collected during spring and fall hunts. Common 

eider and king eider represent species with a strong marine association during the pre-breeding 

migration to their arctic nesting grounds, and the greater white-fronted goose represents a species 

with more terrestrial and near shore association.

Figure 1: Pre- and post- breeding liver sample collection areas. Pre-breeding greater white-fronted goose 

(GWFG) locations were hunted from snow blinds (blue diamonds). Post-breeding GWFG locations were 

hunted inland on the tundra (red star), and at a pond near Pigniq (local hunting station; red circle). Postbreeding king eider (KIEI) and common eider (COEI) were taken also near Pigniq as birds flew toward 

the Chukchi Sea.

In previous studies, liver biopsies for CYP1A analysis have been frozen within 10 minutes of 

death/biopsy removal (Trust et al. 2000a), and information about potential post-mortem enzyme 

degradation beyond this timeframe has not been reported. To maintain a 10-minute post-mortem 

sampling window, we targeted birds with a verifiable time of death by direct-take or observing 

the death when collecting opportunistic samples. Post-mortem, livers were quickly removed 

through one or two incisions near the spine along the bird’s back. Livers were cut into small 

pieces, samples placed in cryovials (~1 cm3 tissue minimum), and cryovials immediately frozen 

in a cryogenic vapor phase liquid nitrogen dewar (-150oC) in the field. In addition to a standard

10-minute vial, when possible, samples were also frozen at less than 10 minutes post-mortem. To 
5

explore post-mortem degradation of CYP1A and determine an appropriate sampling window, 

additional liver vials were frozen at 20 and 30 minutes and 1, 2, 4, 6, and 24 hours post-mortem. 

Cryovials were kept at outdoor ambient temperatures until their assigned freeze time. Extra vials 

were also frozen at 10 minutes, and 1 and 2 hours to use for laboratory QA/QC and long-term 

freezer storage. While in the field, we collected whole blood and cloacal swabs for archival and 

recorded body mass, age/gender, wing length, culmen and tarsus measurements, and location 

data. Additionally, we collected organ and muscle tissue, bile, feathers, and fat for archival and 

health assessment. All liver samples were transported in the vapor phase liquid nitrogen dewar to 

the Alaska SeaLife Center (ASLC) in Seward, AK, for laboratory analysis. Once at the ASLC,

liver samples were transferred to -80oC for storage. 

Liver EROD assay

Embryonated mallard eggs were injected with a dose of 4mg beta-naphthoflavone (BNF; 

dissolved in peanut oil) at day 11 of incubation to act as a positive assay control. The shell was 

first cleaned with povidone iodine solution and two small holes were made at the top of the air 

cell (one hole for injection of a dose, one to alleviate air pressure during dosing) taking care not 

to break the internal air cell membrane. After dosing, holes were sealed with liquid Band-Aid© 

and eggs wereplaced upright for 10–30 minutes. Eggs were then returned to the incubator until 

liver extraction 24 hours later. Eggs were sterilized with povidone iodine, opened around the air 

cell using scissors, and the embryo quickly located and decapitated. The torso was placed in a

petri dish and the liver, without the gallbladder, removed and placed in a cryovial. Embryo livers 

from 1–4 birds were pooled in cryovials and frozen in liquid nitrogen within 10 minutes of death. 

Samples were kept in liquid nitrogen until microsome extractions.

We used microsome EROD activity to measure CYP1A levels in liver samples following the 

methods of Trust et al. (2000a) and Miles et al. (2007) and standard laboratory QA/QC 

procedures. Microsomes were extracted within six months of collection from 50-100mg of liver 

tissue homogenized with 500 μL cold homogenizing buffer (0.05M Tris, 0.15M KCl, pH 7.4). 

Each homogenate was then centrifuged for 20 minutes at 10,000 xg at 2oC. The resulting 

supernatant was transferred to a new cold vial and spun for 60 minutes at 20,800 xg at 2oC. This 

supernatant was removed and the microsome pellet was resuspended in 100 μL cold 

resuspension solution [50 mM Tris, 1 mM ethylenediaminetetraacetic acid, 1 mM

dithiothreitol, and 20% (v/v) glycerol, pH 7.4]. To determine EROD activity, microsomes were 

plated in triplicate in a 96-well plate and read using a Gemini EM Dual-Scanning Microplate 

Spectrofluorometer fluorescent plate reader (Molecular Devices, Sunnyvale, CA). Resorufin at 0, 

5, 10, 20, 40 and 60pM acted as a positive control for each assay. Each well contained 200 μL

consisting of 10 μL microsomes (or resorufin), 150 μL 2.5 μM 7-ethoxyresorufin (7-ER) in 50 

mM Tris buffer (pH 8.0), and 40 μL 1.34 μM catalyst nicotinamide adenine dinucleotide 

phosphate (NADPH) in 50 mM Tris buffer (pH 8.0). Fluorescence was measured once every 

minute for six minutes at an excitation wavelength of 530 nm and an emission wavelength of 590

nm. EROD activity was expressed as pmol/min and results were averaged over the triplicates 
6

with mean calculated. Protein levels (mg) were determined by diluting 1 μL microsomes with 4

μL dH2O and using the Bradford reagent (Sigma, St. Louis, MO). Final EROD activity was 

expressed as pmol/min/mg protein and calculated using the formula:

EROD activity = (EROD pmol/min) / EROD sample volume (0.01 mL) / mg protein

Sensitivity to Hydrocarbon Exposure

Source material

Eggs from several species were acquired from private or commercial breeders: mallard eggs 

from Murray McMurray Hatcheries (Webster City, IA), efowl.com (Denver, CO), and Metzer 

Farms (Gonzales, CA); chicken eggs from Murray McMurray Hatcheries, efowl.com, and 

Stromberg’s Chick and Game Birds Unlimited (Pine River, MN); domestic goose from Murray 

McMurray Hatcheries; common eider and king eider eggs from Dry Creek Waterfowl (Port 

Angeles, WA); domestic goose and brant eggs from private breeders (Washington). Additionally, 

the ASLC (Seward, AK) provided eggs from captive research or collection birds including

Steller’s eider, spectacled eider, tufted puffin, horned puffin (Fratercula corniculata), long-tailed 

duck, and common murre. In 2015 and 2016, greater white-fronted goose and common eider 

eggs were collected on the North Slope (Barrow area and Kaktovik, respectively). 

Egg development

After arrival at the laboratory, eggs were given an individual identification number, dipped in 1X 

chlorhexidine solution, and allowed to air dry. Eggs were either placed directly into an incubator 

or kept at room temperature at a 45° angle for 1–48 hours. Eggs kept longer than 12 hours were 

turned 180° every 12 hours. Artificial incubation occurred in a Grumbach incubator (Grumbach, 

Germany) at 37.5°C with 50–60% humidity. Eggs were placed on shelves in the incubator on top 

of rollers which slowly moved, gently rolling the egg over 24 hours. Incubator settings also 

included two 30-minute breaks with no heat per 24-hour period (at 10 and 14 hours). During 

development, eggs were monitored every 3–5 days by candling. Eggs that were infertile or 

stopped developing were removed from the incubator.

Hepatocyte cell extraction

Using established primary cell culture protocols (Hollmén et al. 2008–2012, Brendler-Schwaab 

et al. 1994) and following standard cell culture QA/QC (Freshney 2000), embryonic liver tissue 

was harvested at approximately 11–18 days of incubation for all species. Egg shells were 

sterilized with povidone iodine solution prior to opening. Using scissors, the top of the shell 

around the air cell was removed, the embryo located and quickly decapitated. The torso was 

removed and placed in a petri dish, and the liver, without the gallbladder, was removed and 

placed in cold 1X PBS. Livers were pooled in groups of 1–4 and rinsed with pre-perfusion buffer 

II [Hanks Balanced Salt Solution 1x (HBSS) without CaCl2 and MgCl2, 10 mM HEPES, and 

0.5 mM EGTA (pH 7.4)]. The buffer was removed and livers were minced gently using sterile 

scalpels. Liver tissue and perfusion medium II [minimum essential medium (MEM) without L-
7

glutamine, collagenase IV (100U) and 0.125% trypsin] were added to a trypsinizing flask and 

digested for 30 minutes at 37°C with gentle stirring. Digestion was stopped with the addition of 

20% heat inactivated FBS (HI FBS). The resulting mixture was filtered through nylon mesh (100

μM) into a sterile tube containing pre-perfusion buffer. The cell suspension was centrifuged at 

63g and 4°C for 5 minutes. The supernatant was removed and the resulting cell pellet was gently 

resuspended in pre-perfusion buffer and spun at 110 xg and 4°C for 5 minutes. At this point, 

additional liver suspensions were combined, if necessary, to bring the total number of livers used 

per culture to 4–12. The supernatant was removed and the cell pellet was gently resuspended in 

low glucose media [high glucose Dulbecco's Modified Eagle Medium (DMEM), MEM, 

antibiotic mixture (nystatin, penicillin-streptomycin, and gentamycin) and L-glutamine] and 20% 

HI FBS. A cell count was then performed using a hemocytometer. Finally, hepatocyte cells were 

seeded in a black-walled 96-well plate at 30,000 cells/well and a total well volume of 200 μL. 

All cell lines were incubated at 37°C in 5% CO2 atmosphere. Every 24 hours, cultures were 

given fresh media with 20% HI FBS and cells were checked by microscopy for confluency level, 

health, and morphology (Hollmén et al. 2002). Cell cultures were incubated at 37°C in 5% CO2

atmosphere for 24–48 hours before dosing.

Cell culture QA/QC

Eggs, cell culture stocks, and reagents were all assigned individual lot and/or tracking numbers. 

Aseptic techniques were used for all cell culture protocols and work was performed in a 

biosafety cabinet. All buffer and media reagents were purchased from Invitrogen (Grand Island, 

NY), Sigma-Aldrich (St. Louis, MO), Fisher Scientific (Pittsburg, PA), or VWR (Radnor, PA).

Cell culture assays

Before dosing, media was removed from the wells and cells gently washed 1–2 times with 1X 

PBS to remove any cellular debris. Cultures were then given fresh media (100 μL with no FBS) 

and were dosed, in triplicate, with carrier solvent control dimethyl sulfoxide (DMSO) or ethanol, 

negative controls (media only and cells with no dose), and different concentrations of reference 

laboratory chemicals and compounds (BNF, chrysene, or phenanthrene) or compound mixture 

Alaska North Slope Crude Oil (ANS oil; Marathon Alaska Beaver Creek Crude Oil-Sweet). BNF 

is a standard laboratory chemical that is a known inducer of CYP1A activity and has been used 

in previous studies to measure avian EROD responses (Miles et al. 2007, Hollmén et al. 2008–

2012). Phenanthrene and chrysene represent polycyclic aromatic hydrocarbons of different 

molecular weights (3- and 4-ring, respectively) found in crude oil and which induce CYP1A 

activity (Incardona et al. 2005, Short et al. 2008). Doses were diluted with low glucose media,

when necessary, and stored in amber vials at 4°C. Following 12–36 hour incubation (typically 

24-hour exposure) cells were first evaluated using microscopy for general cell morphology and 

cytopathic effects (CPE). Types of CPE observed were characterized and described for each cell 

line and test material used. Cells were scored on a semiquantitative response scale from 0–4 

(0=none to 4=100 % effect) for a variety of CPE responses including vacuolarization, 

cytoplasmic swelling, and cellular debris (Hollmén et al. 2008–2012; Table 1). 
8

Table 1: Cytopathic effects (CPE) measurements.

General culture evaluation

Cell sheet confluency, general cell morphology

Culture responses Scoring system

granularization

Semiquantitative response 

grade 0-4 

(0=none to 4=100% effect)

vacuolarization

cytoplasmic swelling

non-viability

cellular debris

other

Adapting EROD methods from Hodson et al. (1996) and Hahn et al. (1996), a solution of 6 μM

7-ethoxyresorufin (7-ER) was freshly prepared from 100 μM 7-ER stock and NaPO4 buffer and 

25 μL added to each well. Next, catalyst NADPH was resuspended in 1.5 mL NaPO4 buffer and 

10 μL added to each well. Fluorescence was then immediately measured at excitation 

wavelength of 530 nm and an emission wavelength of 590 nm using a Gemini EM DualScanning Microplate Spectrofluorometer fluorescent plate reader (Molecular Devices, 

Sunnyvale, CA). EROD activity was measured every 15 minutes for 3 hours to capture the 

threshold activity level. Results were averaged over the triplicates and standard error calculated. 

Cell count per well was uniform, and protein was not quantified (Hahn et al., 1996). Mallard 

results were used as an assay control and reference comparison. 

Analytical Techniques

Curve fitting

Curve fitting has been used to characterize the dose-response relationships observed in cellular 

assays (Springman et al. 2008, Short et al. 2008) using regression analysis. Types of comparisons 

can include the relative potency of reference compounds within a species and the sensitivity of 

each species relative to a reference species. The method of comparison is based on the shape of 

the response among species and compounds, and then determining half maximum effective 

concentrations (EC50), calculating concentrations that produce a response equivalent to an

assigned % of the maximum response produced by the compound (for example, 10%), or 

comparing slope ratios (Finney 1978). We explore the use of five-parameter logistic curves to 

estimate dose-response values and variation between species and linear mixed models 

(Gottschalk and Dunn 2005). The five-parameter formulation allows for a range of response 

curves from the group of species and can be tested explicitly for goodness of fit before use in 

comparisons.
9

Sensitivity assessment

Species sensitivity is compared using data from controlled cell dosing experiments. The 

embryonic stage was monitored by candling and made comparable among species by adjusting 

the extraction time to incubation stage so embryos represented a similar stage of development at 

the time of cell line establishment. The responses were compared using reference reagents and 

standardized dosing concentrations and procedures. The fitted response curves for each of the 

species were compared. Mallard represented a reference responder (Hollmén et al. 2008–2012). 

Species were assigned a relative rank based on their responses. Additionally, assessment of CPE 

provided a metric to evaluate potential cellular-level toxicity relating to the experimental dose 

and associated enzyme response. 

RESULTS

Current CYP1A Activity

Liver collections

Table 2 presents the sample sizes for birds sampled during pre- and post-breeding harvest in 

collaboration with the North Slope Borough Department of Wildlife Management. A total of 33 

days in 2014, 30 days in 2015, and 12 days in 2016 were spent in Barrow for liver collections,

with the first collections occurring in August 2014. All birds were collected using direct-take 

except two king eiders that were sampled opportunistically, one within 10 minutes of death. 

Complete time series samples were collected from all birds, excluding the king eider that was

collected after 10 minutes post-mortem. In 2014, time series samples included 10, 20, 30 minutes 

and 1 and 2 hours. In 2015, the time series was adjusted to 10, 20, 30 minutes and 1, 2, 4, 6, and 

24 hours. The longer time points were added in response to learning more about when hunters 

butcher their birds. Also, 81 of 93 birds had an additional liver sample collected and frozen at 

<10 minutes.

Table 2: Birds collected during pre- and post-breeding hunts over the course of this project.

Microsome EROD

Table 3 shows median EROD results (pmol/min/mg protein) from microsome liver samples from 

pre-breeding 2015 (n=236), pre-breeding 2016 (n=210), post-breeding 2014 (n=141) and postbreeding 2015 (n=352) field seasons. Individual EROD results at 10 minutes post-mortem (the 

current collection protocol) ranged from 0–284 pmol/min/mg protein in king eiders, 27–367 

Species

Birds sampled

Post-breeding 

2014

Birds sampled 

Pre-breeding 

2015

Birds sampled 

Post-breeding 

2015

Birds sampled

Pre-breeding 

2016

Greater white-fronted goose 9 20 13 18

King eider 7 --- 15 ---

Common eider 9 --- 2 ---
10

pmol/min/mg protein in common eiders, and 0–915 pmol/min/mg protein in greater whitefronted geese. The highest EROD activity responses were found in post-breeding greater whitefronted geese in 2014. 

Table 3: Median EROD results (pmol/min/mg protein) with sample size by species, season, and time vial 

was frozen post mortem for all collected liver samples. (KIEI=-king eider, COEI=common eider, 

GWFG=greater white-fronted goose).

EROD results indicate enzyme activity throughout the post-mortem time series, including 

samples frozen 24 hours after death. Results for QA/QC duplicate microsome extractions (Table 

4) show a similar response between the two extracts. Table 5 reports EROD results for the 

freezer storage experiment. The original samples from post-breeding collections in 2014 were 

extracted in February 2015 (within six months of collection). The same samples, from a vial that 

had not been previously thawed, were re-extracted in 2015 after 16 months in storage at -80°C. 

The EROD results suggest some decrease in enzyme activity during long-term freezer storage.

Time

KIEI

postbreeding

2014

KIEI

postbreeding 

2015 

COEI

postbreeding 

2014

COEI

postbreeding 

2015 

GWFG

prebreeding 

2015 

GWFG

prebreeding 

2016 

GWFG

postbreeding 

2014

GWFG

postbreeding 

2015 

<10 min 112.07 

(n=5)

25.70 

(n=10)

257.95 

(n=7)

73.36 

(n=2)

69.93 

(n=20)

87.52 

(n=18)

417.72 

(n=9)

20.03 

(n=10)

10 min 92.65 

(n=6)

19.97 

(n=15)

254.51 

(n=9)

32.97 

(n=2)

89.80 

(n=20)

82.78 

(n=18)

518.57 

(n=9)

25.04 

(n=13)

20 min 135.71 

(n=6)

20.27 

(n=15)

225.42 

(n=9)

36.93 

(n=2)

104.82 

(n=20)

68.79 

(n=17)

406.69 

(n=9)

23.62 

(n=13)

30 min 152.34 

(n=6)

16.92 

(n=15)

236.02 

(n=9)

81.01 

(n=2)

108.43 

(n=20)

85.19 

(n=17)

379.59 

(n=9)

22.50 

(n=13)

1 hr 151.14 

(n=6)

25.88 

(n=15)

235.89 

(n=9)

82.60 

(n=2)

94.94 

(n=20)

89.27 

(n=18)

388.66 

(n=9)

23.78 

(n=13)

2 hr 157.54 

(n=6)

22.47 

(n=15)

260.24 

(n=9)

87.31 

(n=2)

122.71 

(n=20)

71.46 

(n=17)

535.01 

(n=9)

28.64 

(n=13)

4 hr --- 16.30 

(n=15)

--- 61.84 

(n=2)

133.60 

(n=20)

63.76 

(n=17)

--- 23.15 

(n=13)

6 hr --- 14.32 

(n=14)

--- 53.16 

(n=2)

156.08 

(n=20)

87.35 

(n=18)

--- 23.23 

(n=13)

24 hr --- 38.17 

(n=2)

--- 38.17 

(n=2)

109.72 

(n=16)

88.94 

(n=17)

--- 21.11 

(n=13)
11

Table 4: Median EROD results (pmol/min/mg protein) with sample size by species, season, and time vial 

was frozen post-mortem for duplicate microsome extraction QA/QC. (KIEI=-king eider, COEI=common 

eider, GWFG=greater white-fronted goose). 

10 Minutes 60 Minutes 120 Minutes

First

replicate

Second 

replicate

First

replicate

Second 

replicate

First

replicate

Second 

replicate

GWFG

pre-breeding 2015 

99.09 

(n=16) 90.91 (n=16) 128.36 (n=15)

114.23 

(n=15)

125.75 

(n=15)

142.38 

(n=15)

GWFG

post-breeding 2015 

19.99

(n=13)

28.01

(n=13)

22.48

(n=13)

20.32

(n=13)

21.50

(n=13)

31.62

(n=13)

GWFG

pre-breeding 2016

88.83 

(n=18) 73.36 (n=18) 87.17 (n=18)

90.96 

(n=18)

66.65 

(n=17)

67.27 

(n=17)

COEI

post-breeding 2015 

34.66

(n=2)

31.27

(n=2)

65.05

(n=2)

100.14

(n=2)

110.67

(n=2)

63.94

(n=2)

KIEI

post-breeding 2015 

19.62

(n=15)

25.86

(n=15)

27.05

(n=15)

19.54

(n=15)

24.15

(n=15)

20.90

(n=15)

Table 5: Median EROD results (pmol/min/mg protein) for 10-minute post-mortem samples (2014 postbreeding) from freezer storage experiment.

Species

Activity 

(pmol/min/mg protein)

Extracted Feb 2015

EROD Feb 2015

Activity

(pmol/min/mg protein)

Extracted Dec 2015

EROD Feb 2016

Greater white-fronted goose (n=9) 518.57 68.49 

King eider (n=5) 94.64 36.62 

Common eider (n=9) 254.51 30.23 

Hydrocarbon Sensitivity

Source material

During the course of this study we received eggs from nine of our ten target species: Steller’s 

eider, common eider, king eider, spectacled eider, long-tailed duck, common murre, tufted 

puffin, black brant, greater white-fronted goose, and surrogate domestic goose. We were unable 

to procure any eggs from black or pigeon guillemots. In 2015, we were able to acquire eggs from 

an additional species, the horned puffin. Chicken cultures were generally of low quality and we 

did not acquire adequate materials for high through-put assays. We purchased mallard eggs from 

several different vendors after noticing a variation in culture quality among sources. In 2015 and 

2016, we received goose and eider eggs from the North Slope. Greater white-fronted goose eggs 

were collected near Barrow and common eider eggs were collected opportunistically around 

Kaktovik. In 2015, 19 of 20 twenty greater white-fronted goose eggs were damaged during 
12

shipment or were not viable. The one remaining egg was fertile but the cells failed to grow after 

extraction. 

Cell culture assays

We conducted a total of 51 EROD assays and assessed cytopathic effects (CPE) using liver cells 

cultured from ten marine bird species and mallard as a reference responder. Tables A1–A4 (see 

Appendix A) report the number of EROD repeats for each species and dose at 24-hour dose 

exposure. 

We were able to obtain a large number of Steller’s eider eggs during 2015 cell culture laboratory 

work. This allowed testing of many dose concentrations for our target compounds (chrysene, 

BNF, phenanthrene, and Alaska North Slope crude oil) and repeated testing of these doses. 

EROD Figures 2–8 and CPE tables B1–B7 (see Appendix B) summarize the results for Steller’s 

eider. 

Figure 2 shows enzyme responses of Steller’s eider cells to a range of chrysene concentrations 

(0.5–5.0 μM) after a 24-hour dose exposure. Steller’s eider had the highest response to 1.5 μM

chrysene with responses decreasing with higher dose concentration. Cellular debris and amount 

of non-viable cells increased slightly with increasing dose concentration (appendix Table B1). 

Steller’s eider cell culture results at 24- hour exposure to BNF concentrations (0.5–5.0 μM) are 

presented in Figure 3. The highest enzyme response was from 2.0 μM BNF and the lowest from 

5.0 μM BNF. There was minimal change in cytopathic effects from the different BNF 

concentrations (appendix Table B2). Testing with the single hydrocarbon phenanthrene (0.5–

50.0 μM) started in 2015, and results from Steller’s eiders are shown in Figure 4 (24-hour dose 

exposure). Even with a higher concentration range then the other testing compounds, there was 

no enzyme response to this hydrocarbon in Steller’s eider and only a slight response in mallard 

(data not shown). However, phenanthrene at higher concentrations produced a black material 

(“asphalting”) that coated the well and obscured CPE readings of the cultures (appendix Table 

B3). 

In 2015, we acquired Alaska North Slope Crude oil (NS oil) to use in dosing experiments. Figure 

5 shows Steller’s eider results from a 24-hour dose exposure to 0.5–20.0 μL neat NS oil. The 

highest enzyme response was at 5.0 μL oil with response decreasing with higher dose 

concentrations. These results show a low degree of variation in enzyme activity over the course 

of the EROD assay and indicate maximum cellular activity was potentially reached at these 

doses. Due to the high background from media with oil (no cells) controls, the fluorescent 

responses from these controls were removed from the cellular responses. Cytopathic responses 

were similar for all neat NS oil doses with a slight increase of non-viable cells observed at the 

higher doses (appendix Table B4). In experimenting with different concentrations of NS oil, we 

tested three doses diluted with media and carrier reagent DMSO (Figure 6) and used 100 μL per 

well: #1 20 μL 1:1 oil:DMSO with 2 mL media, #2 10 μL 1:1 oil:DMSO with 2 mL media, #4 5

μL 1:1 oil:DMSO with 2 mL media. These doses did not elicit a strong enzyme response in 
13

Steller’s eider but had a larger amount of non-viable cell and cellular debris (appendix Table B5) 

than neat NS oil doses. To further explore diluted NS oil doses, we also dosed Steller’s eider 

cells with higher concentrations of oil with DMSO (1 part oil to 1 part DMSO up to 10 parts oil 

and 1 part DMSO, Figure 7). Dose 1:1 oil:DMSO had the lowest enzyme response but also the 

highest amount of cellular debris in the well (appendix Table B6). It is likely this dose 

overwhelmed the cell culture, limiting enzyme response. Lastly, using Steller’s eider cells we 

were able to complete three replicates of a 12, 24, and 36-hour 1.0 μM chrysene dose exposure 

experiment (Figure 8). In general, the highest enzyme response was at 12 hours with the lowest 

responses at 36 hours with similar CPE over the course of the experiment (appendix Table B7).

Results for an alcid species (tufted puffin) response to a range of chrysene concentrations (0.5–

2.0 μM) after a 24-hour dose exposure are shown in Figure 9. Tufted puffin responses increased 

as the chrysene concentration increased, and there was no noticeable change in CPE between the 

doses (appendix Table B8). Tufted puffin cell culture results at 24-hour exposure to BNF (0.5–

2.0 μM) concentrations are presented in Figure 10. All three BNF doses produced a very similar 

enzyme response and no CPE change (appendix Table B9).

Results for all species tested (mallard, brant, spectacled eider, common eider, long-tailed duck, 

king eider, domestic goose, greater white-fronted goose, tufted puffin, horned puffin, common 

murre, and Steller’s eider) at 1.0 μM chrysene at 24-hour dose exposure are shown in Figure 11. 

These results suggest differences in species response at this dose but showed no apparent 

difference in pathological response (CPE, appendix Table B10) between control wells and the 

1.0 μM chrysene dose. The alcids showed a similar enzyme response and the ducks responded in 

a similar manner, with the possible exception of Steller’s eider. EROD results for all species 

tested at 1.0 μM BNF (mallard, long-tailed duck, common murre, tufted puffin, common eider, 

domestic goose, greater white-fronted goose and Steller’s eider) at 24-hour dose exposure are 

shown in Figure 12; mallard had the highest response and greater white-fronted goose the lowest. 

CPE results were similar for all tested species (appendix Table B11). Figure 13 represents EROD 

results for five target species (tufted puffin, common eider, common murre, greater white-fronted 

goose, and Steller’s eider) and control species mallard dosed with 1.0 μL NS oil at 24-hour dose 

exposure. Tufted puffin had the highest enzyme response with the other tested species showing a 

similar, and lower, response. CPE results suggest that common murre had a higher amount of 

non-viable cells than other species (appendix Table B12). Finally, Figure 14 shows all tested 

species (tufted puffin, mallard, common murre, greater white-fronted goose, Steller’s eider and 

common eider) responses to 5.0 μL oil after 24-hour dose exposure. All species showed a similar 

enzyme response and a response higher than at 1.0 μL oil. Again, common murre appeared to 

have a higher amount of non-viable cells, and common eiders showed a larger amount of cellular 

vacuolarization (appendix Table B13).
14

Figure 2: EROD responses (with standard error and sample size) in Steller’s eider to different 

concentrations of chrysene doses with 24-hour dose exposure. Results from 2013-2015 for each dose 

were combined. Cell and media controls are also included. 

Figure 3: EROD responses (with standard error and sample size) in Steller’s eider to different 

concentrations of BNF doses with 24-hour dose exposure. Results from 2013-2015 for each dose were 

combined. Cell and media controls are also included. 
15

Figure 4: EROD responses (with standard error and sample size) in Steller’s eider to different 

concentrations of phenanthrene doses with 24-hour dose exposure. Results from 2015 for each dose were 

combined. Cell and media controls are also included. 

Figure 5: EROD responses (with standard error and sample size) to different amount of neat Alaska 

North Slope crude oil dose and cell control with 24-hour dose exposure in Steller’s eider. Results from 

2015 for each dose were combined. The fluorescence response of media + 0.5-20 μL oil (no cells) was 

removed from the cellular response for each corresponding dose. 
16

Figure 6: EROD responses (with standard error and sample size) to different amount of media diluted 

Alaska North Slope crude oil dose and cell and media control with 24-hour dose exposure in Steller’s 

eider. 100 μL of each diluted dose was added to the well. Doses consisted of: #1 20 μL 1:1 oil:DMSO 

with 2 mL media, #2 10 μL 1:1 oil:DMSO with 2 mL media, #4 5 μL 1:1 oil:DMSO with 2 mL media.

Figure 7: EROD responses (with standard error and sample size) to different amount of DMSO diluted 

Alaska North Slope crude oil doses and cell and media control with 24-hour dose exposure in Steller’s 

eider. 
17

Figure 8: EROD responses (with standard error) in Steller’s eider to 1.0 μM chrysene dose with 12, 24, 

and 36-hour dose exposure. Each of three replicates (#1, #2, #3) is labeled next to the exposure time.

Figure 9: EROD responses (with standard error and sample size) in tufted puffin to different 

concentrations of chrysene doses with 24-hour dose exposure. Cell and media controls are also included.
18

Figure 10: EROD responses (with standard error and sample size) in tufted puffin to different 

concentrations of BNF doses with 24-hour dose exposure. Cell and media controls are also included. 

Figure 11: EROD responses (with standard error and sample size) in ten marine bird species and mallard 

control to 1.0 μM chrysene dose with 24-hour dose exposure. Results from 2013-2016 for each species 

were combined. Goose= domestic goose.
19

Figure 12: EROD responses (with standard error and sample size) in six marine bird species and mallard 

control to 1.0 μM BNF dose with 24-hour dose exposure. Results from 2013-2016 for each species were 

combined. Goose= domestic goose.

Figure 13: EROD responses (with standard error and sample size) to 1.0 μL neat Alaska North Slope 

crude oil dose with 24-hour dose exposure in five target species and one control species. The fluorescence 

response of media + 1.0 μL oil (no cells) was removed from the cellular response for each species.
20

Figure 14: EROD responses (with standard error and sample size) to 5.0 μL neat Alaska North Slope 

crude oil dose with 24-hour dose exposure in four target species and one control species. The 

fluorescence response of media + 5.0 μL oil (no cells) was removed from the cellular response for each 

species. 
21

Analysis

Curve fitting

After visualizing trends in the response for Steller’s eider, we found it more appropriate to use a 

linear mixed modeling approach than a traditional logistic response. We tested models of 

response by grouping, time, and cell coverage with a random effect of date. The only significant 

trends in slope of the response were for seven oiled groupings; six had slight negative slopes 

(Figures 15 and 16). Curve fitting results are shown in Figures17-21.

Figure 15: Statistical analysis of Steller’s eider EROD results with assay time in minutes. Doses, except 

for the oil doses, show some minor effects within the group but are not statistically different from no 

effect. 

b05 BNF 0.5μM

b1 BNF 1 μM

b2 BNF 2μM

b5 BNF 5 μM

c05 chrysene 0.5 μM

c1 chrysene 1 μM

c15 chrysene 1.5 μM

c2 chrysene 2 μM

c3 chrysene 3 μM

c5 chrysene 5 μM

o05 oil 0.5 μL

o1 oil 1 μL

o5 oil 5 μL

o10 oil 10 μL

o20 oil 20 μL

od101 10:1 oil: DMSO

od11 1:1 oil:DMSO

od31 3:1 oil:DMSO

od51 5:1 oil: DMSO

on1 oil #1 20μL 1:1 oil:DMSO w/2mL media

on2 oil #2 10μL 1:1 oil:DMSO w/2mL media

on4 oil #4 5μL 1:1 oil:DMSO w/2mL media

p05 phenanthrene 0.5 μM

p1 phenanthrene 1 μM

p10 phenanthrene 10 μM

p2 phenanthrene 2 μM

p5 phenanthrene 5μM

p50 phenanthrene 50 μM

cell cell only control

d13 1:3 media:DMSO control

etoh 1:1 media:ethanol control

med control media only 
22

Figure 16: Statistical analysis of Steller’s eider oil EROD results with assay time in minutes. Real data is 

represented in dots, the solid line is the estimated response trend over time, and the dashed line is the 95% 

confidence interval. These seven doses had slope and intercept parameters significantly different than 0 

indicating some trend in fluorescence over time.
23

Figure 17: Statistical analysis of tested species EROD results to different amount of neat Alaska North 

Slope crude oil. Assay time in minutes is on the x-axis. Real data is represented in dots, the solid line is 

the estimated response trend over time, and the shaded area is the 95% confidence interval. 

Figure 18: Statistical analysis of tested species EROD results to different amount of Alaska North Slope 

crude oil dissolved in carrier reagent dimethyl sulfoxide (DMSO). Assay time in minutes is on the x-axis. 

Real data is represented in dots, the solid line is the estimated response trend over time, and the shaded 

area is the 95% confidence interval.

Species

coei common eider

comu common murre

gwfg greater white-fronted goose

stei Steller’s eider

tupu tufted puffin

Dose groups

o05 oil 0.5 μL

o1 oil 1 μL

o10 oil 10 μL

o20 oil 20 μL

o5 oil 5 μL

Species

mall mallard

stei Steller’s eider

tupu tufted puffin

Dose groups

od101 10:1 oil: DMSO

od11 1:1 oil:DMSO

od31 3:1 oil:DMSO

od51 5:1 oil: DMSO
24

. 

Figure 19: Statistical analysis of tested species EROD results to different amount of media diluted 

Alaska North Slope crude oil. Assay time in minutes is on the x-axis. Real data is represented in dots, the 

solid line is the estimated response trend over time, and the shaded area is the 95% confidence interval. 

Oil doses all in 1:1 oil:DMSO w/2 mL media.

Figure 20: Statistical analysis of tested species EROD results to different amount of BNF. Assay time in 

minutes is on the x-axis and fluorescence on the y-axis. Real data is represented in dots, the solid line is 

the estimated response trend over time. 

Species

coei common eider

mall mallard

stei Steller’s eider

tupu tufted puffin

Dose groups

on1 oil #1 20μL 

on2 oil #2 10μL 

on4 oil #4 5μL 

Species

coei common eider

comu common murre

goose domestic goose

gwfg greater white-fronted goose

ltdu long-tailed duck

mall mallard

stei Steller’s eider

tule domestic tule goose

tupu tufted puffin

Dose groups

b05 BNF 0.5μM

b1 BNF 1 μM

b10 BNF 10μM

b15 BNF 1.5 μM

b2 BNF 2 μM

b25 BNF 2.5μM

b5 BNF 5 μM
25

Figure 21: Statistical analysis of tested species EROD results to different amount of chrysene. Assay time 

in minutes is on the x-axis. Real data is represented in dots, the solid line is the estimated response trend 

over time. 

DISCUSSION

Field Collections

Samples were primarily collected by direct-take during this project to ensure we were obtaining 

liver samples within the recommended 10-minute timeframe post-mortem. Using direct-take, 

collecting and sampling all three species within 10 minutes of death is feasible. We found that 

opportunistic sampling within 10 minutes of death may be challenging and requires a close 

relationship with a willing subsistence hunter. After spending many hours in the community 

hunting and talking with hunters, we have begun to form relationships that will likely lead to 

future collaborations. One such collaboration resulted in an opportunistic sample within the 

recommended 10 minute post-mortem window in fall 2015. Due to the nature of goose and eider 

hunting around Barrow, king and common eider samples will be most feasible to obtain in the 

fall due to the close proximity between hunters and more opportunities for social interactions 

(Figure 22). Based on discussions with hunters, we may have future opportunities for spring 

Species Dose groups

brant brant ltdu long-tailed duck c05 chrysene 0.5 μM

coei common eider mall mallard c1 chrysene 1 μM

comu common murre spei spectacled eider c10 chrysene 10 μM

goose domestic goose stei Steller’s eider c15 chrysene 1.5 μM

gwfg greater white-fronted goose tule domestic tule goose c2 chrysene 2 μM

hopu horned puffin tupu tufted puffin c25 chrysene 2.5 μM

kiei king eider c3 chrysene 3 μM

c5 chrysene 5 μM
26

eider sampling if we are able to team up with a whaling camp. During spring, the whaling camps 

are set up along ice edges, and eiders are hunted during slow periods. These birds are butchered 

on site. During spring goose hunts, hunters are spread out and hunt from solitary snow blinds or 

travel away from town for multi-day hunts. We also discovered there are very few hunters 

targeting geese in the fall due to their preference for eiders in that season.

Figure 22: Hunters outside their cars hunting flocking eiders near Barrow, AK, August 2015.

A key step to collecting samples less than and within 10 minutes of death was supply preparation 

and teamwork. This included pre-labeled vials, good organization of supplies that can be 

accessed easily and quickly and a minimum of two people. While the hunter retrieved the bird, 

typically by foot, occasionally by kayak, the second person prepared the workstation on the 

tailgate of the truck (in fall, Figure 23) or in the snow blind (in spring, Figure 24). The 

experience of the hunter was extremely valuable as he was skilled at targeting birds he could

retrieve within the short timeframe and quick in extracting livers. 

Figure 23: Slicing a greater white-fronted goose liver for sampling. Robert Sarren (North Slope Borough 

Department of Wildlife Management) cuts liver samples into smaller pieces in Barrow, AK, August 2015. 

We commonly used the back gate of the truck as our processing station.
27

Figure 24: Processing a greater white-fronted goose in a snow blind near Barrow, AK, May 2015. 

Pictured: Robert Sarren (North Slope Borough Department of Wildlife) and Ann Riddle-Berntsen (UAF 

CFOS graduate student). 

For liver sample collections, we used a small (5 L), portable liquid nitrogen dewar and a large 

(20 L) dewar. The larger dewar proved more useful for our collections because it was able to 

hold more vials at temperature for over a month. Dewar size was not an issue during hunts as we 

often hunted very close to the truck or, during spring hunts, used snow machine sleds to haul 

gear to snow blinds. The smaller dewar was only able to hold tubes from 2–3 birds due to the 

volume of liver tubes collected for the time series sampling, limiting the birds we could collect 

during a day. Also, the temperature charge lasted less than two weeks. The length of temperature 

charge was very important as there are no liquid nitrogen facilities in Barrow to recharge dewars 

and we often were in Barrow for two or more weeks per hunt. The smaller dewar will be useful 

for future collections when fewer vials per bird need to be collected and vials can be poured into 

the larger dewar at base camp for storage and shipping. Additionally, the smaller dewar could be 

useful to send out with willing hunters for opportunistic collections due to its small footprint and 

weight and may be especially useful in more remote locations due to size and ease of handling.

We also found it was easier to store all liver vials in the larger dewar while in Barrow rather than 

transfer them to an onsite -80oC freezer. Space was extremely limited in the -80oC freezer and 

keeping samples in the dewar allowed for less sampling handling reducing the risk of samples 

partially thawing. We had no issues transporting samples from Barrow to the laboratory in 

Seward in the 20 L dewar. The dewars are not regulated as a hazardous material so the dewars 

could be safely shipped on passenger planes and ground transport.

Teaming with a North Slope Borough employee, who is also a local subsistence hunter, was 

extremely valuable to this project. His knowledge about the area, birds, and hunting was the key 

to the success of the liver collections. He also introduced us to local hunters who provided our 

two opportunistic samples. His support and enthusiasm for the project were passed onto other 

hunters and members of the community.
28

CYP1A Activity

We adapted previously published microsome extraction and EROD protocols (Trust et al. 2000a 

and Miles et al. 2007) for work in our laboratory. To validate the extraction process we tested 

CYP1A activity in the post-mitochondrial fraction before the 20,800 xg 60-minute spin and the 

supernatant resulting from that spin (a fraction that would normally be tossed). Each fraction 

showed some CYP1A activity but was on average 3–10 times lower than microsome fraction 

activity, confirming that we were correctly using the fraction with the highest CYP1A activity.

Our assay validation and quality control included repeat assay of resorufin controls at different 

concentrations to verify consistency, and repeat assays at the same time points to identify 

variation among EROD assay runs.

Our EROD results indicate enzyme activity in liver samples through our time series samples, 

including those frozen 24 hours after death. Our goal of evaluating whether a recommendation 

could be made to allow an extension on sample collection window from 10 minutes needs further 

analysis. Due to a high degree of individual variability within and among species, we are 

exploring the use of a more complex model structure to assess the effects of time on enzyme 

response. Based on our current findings, we recommend maintaining the current protocol to 

freeze liver samples within 10 minutes of death if they will be used in enzyme analysis.

In a freezer storage experiment, samples kept at -80°C for over one year appeared to have lost 

enzyme activity when compared to the same samples extracted within six months of collection. 

Based on our findings, we recommend processing of samples within the currently used 

timeframes.

We consider most of our EROD results among species and seasons to represent activities that are 

similar to those reported for sea duck species sampled in areas considered unexposed to oil in 

Alaska, although absolute enzyme concentrations are not necessarily directly comparable among 

these different studies. Trust et al. (2000a) reported average activity of 49.5 and 70.7 

pmol/min/mg protein in Barrow’s goldeneye and harlequin ducks in areas untouched by the 

Exxon-Valdez oil spill in Prince William Sound, Alaska, and 94.3 and 204.6 pmol/min/mg 

protein in spill areas. Measuring EROD activity in harlequin ducks in Prince William Sound, 

Esler et al. (2010) reported activity of 15–25 pmol/min/mg protein in unoiled and 75–100 

pmol/min/mg protein in oiled areas. EROD activity in Steller’s eiders and harlequin ducks from 

clean reference site around Unalaska, Alaska, were 10–15 and 50 pmol/min/mg protein, 

respectively, and activity in birds from industrial areas were 20–50 and 100–275 pmol/min/mg 

protein, respectively. 

In 2014, post-breeding samples showed the highest EROD activity. One king eider and one 

white-fronted goose were found in poor body condition, but all other birds in this group appeared

healthy in post-mortem examination. Future research may involve supplementary tests, such as 

hormone analysis, to further determine the health of all sampled birds and physiological factors 
29

potentially affecting seasonal variation in enzyme activity. In addition, archived liver and kidney 

samples could be used for direct measurement of potential contaminants.

Hydrocarbon Sensitivity

We were able to acquire greater white-fronted goose and common eider eggs from the field in 

2015 and 2016. Transporting eggs from remote locations can be challenging, and in both years 

we experienced some breakage during transport. We recommend shipping eggs in multiple 

shipments, using large amounts of packing material, and using hard sided packing containers.

Liver cell culture extraction, EROD, and CPE assays were already validated for many species in 

our laboratory. During the course of this project, we expanded the work to new species, which 

required us to validate detailed protocols and reagents for each new species. Overall, species 

responded similarly to our protocols with the exception of common murre cells, which required 

extra washings with PBS 24 hours after seeding due to a large amount of red blood cells present 

on top of the culture (Figure 25). In addition, common murre cells occasionally had a high 

response to control doses of DMSO and ethanol (see Appendix C). To account for this 

background activity, EROD responses from DMSO and ethanol control wells were subtracted 

when these carrier reagents were used. To remove any dose specific background activity, any 

observed activity in oil+media controls was subtracted from test dose enzyme results in all tested 

species.

 

Figure 25: Common murre liver cell culture with red blood cell contamination before (A) and after (B) 

washing with phosphate-buffered saline (PBS). 

CONCLUSIONS

We developed and tested field protocols for collection of liver samples from hunter-killed 

specimens of Arctic marine birds for EROD analysis. Our study offers guidelines and field 

sampling protocols and refined techniques for sample collection from hunter-killed specimens.

Due to a high degree of individual variability within and among species, we are exploring the use 

of a more complex model structure to assess the effects of post-mortem sampling time on 

enzyme response. Based on our findings, we recommend maintaining the current protocol to 

A B
30

freeze liver samples for enzyme analysis within 10 minutes of death. We present a reference data 

set for three marine bird species from the Arctic: common eider, king eider, and greater whitefronted goose. Common eider and king eider represent species with a strong marine association 

during the pre-breeding migration to their Arctic nesting grounds, and greater white-fronted 

goose represents a species with more terrestrial and near shore association. All three species are 

important subsistence resources for communities in the Arctic. 

Our study contributes to the development of future monitoring plans by providing information 

about the sensitivity of a suite of candidate species to CYP1A induction by crude oil and its 

reference compounds. Species that rank sensitive to induction are potentially sensitive indicators 

and ecosystem sentinels (i.e., first species to show evidence of exposure or physiological 

effects). Our recommendations and conclusions about species sensitivity to hydrocarbons are 

based on a large amount of liver cell culture EROD data from our target species. Overall, 

common murre exhibited consistently high responses at tested doses. Long-tailed duck, while not 

dosed with oil, had a high enzyme response to chrysene and BNF. Tufted puffin had high 

responses to BNF and oil dosing and a moderate response to chrysene. Common eiders 

responded high to 1 μM chrysene but had moderate enzyme response to BNF and oil doses. 

Greater white-fronted geese and surrogate domestic geese were low responders at all test doses.

Steller's eider response to chrysene and BNF doses were low but showed a variable (low to high) 

response to oil dosing. Brant and spectacled eider had high responses to chrysene while horned 

puffin and king eider responses were low to chrysene. Unfortunately, we were unable to acquire 

enough cell material to conduct the full dosing regimen.

In summary, common murre and common eider represented species that showed moderate to 

high responses to a suite of testing doses. Therefore, our findings suggest they are potentially

sensitive candidate species to target in monitoring programs. However, our response results 

suggest that multiple species are likely suitable candidate species so, as a group, marine birds 

offer a diversity of options for ecological indicator species.

ACKNOWLEDGEMENTS

We would like to thank the Coastal Marine Institute and the Bureau of Ocean Energy 

Management (BOEM) for funding this project. We also thank our collaborators and co-authors at 

the North Slope Borough Department of Wildlife Management (NSB-DWM). Robert Suydam, 

Raphaela Stimmelmayr, and Robert Sarren for invaluable support. We received additional 

support from NSB-DWM staff Dave Ramey, Ryan Klimstra and Nathan Wilen. We thank eider 

research and avian husbandry staff at the Alaska SeaLife Center, especially laboratory support 

from Katrina Counihan, field support from Sarah Tanedo and Jane Belovarac, and egg support 

from Tasha DiMarzio and Hannah Feltes. We would also like to thank Arnold Schouten, 

Christopher Latty, Claire Montgomerie and Wilhelm Wiese for logistical support and Charles 

Frost for statistical advice and analysis.
31

STUDY PRODUCTS

Riddle A.E. Assessing Hydrocarbon Sensitivity and Establishing Current CYP1A Activity in 

Select Marine Birds and Waterfowl of the Beaufort and Chukchi Seas. M.S. Thesis. University 

of Alaska. 2017. In progress.

Riddle A.E., Hollmén T.E., Suydam R., Sarren R., and Stimmelmayr R. 2016. Sensitivity to 

Hydrocarbons and Baselines of Exposure in Marine Birds on the Chukchi and Beaufort Seas. 

Coastal Marine Institute Annual Review, Anchorage, AK, January 29, 2016 (presentation). 

Riddle A.E., Hollmén T.E., Suydam R., Sarren R., and Stimmelmayr R. 2016. Assessing 

Hydrocarbon Sensitivity and Establishing Current CYP1A Baselines in Arctic Marine Birds and 

Waterfowl. Alaska Marine Science Symposium, Anchorage, AK, January 25–28, 2016 (poster).

Riddle A.E., Hollmén T.E., Suydam R., Sarren R., and R. Stimmelmayr. 2015. Assessing 

Hydrocarbon Sensitivity and Establishing Current P450 Baselines in Select Marine Birds and 

Waterfowl of the Beaufort and Chukchi Seas. Effects of Oil on Wildlife Conference, Anchorage,

AK, May 18–22, 2015 (poster).

Riddle A.E., Hollmén T.E., Suydam R., Sarren R., and R. Stimmelmayr. 2015. Sensitivity to 

Hydrocarbons and Baselines of Exposure in Marine Birds on the Chukchi and Beaufort Seas. 

Alaska SeaLife Center Board of Directors Meeting, Anchorage, AK, April 22, 2015 

(presentation).

Riddle A.E., Hollmén T.E., Suydam R., Stimmelmayr R., and R. Sarren. 2015. Sensitivity to 

Hydrocarbons and Baselines of Exposure in Marine Birds on the Chukchi and Beaufort Seas. 

University of Alaska, School of Fisheries and Ocean Sciences IMS Seminar, Fairbanks, AK, 

April 15, 2015.

Riddle A.E., Hollmén T.E., Suydam R., Stimmelmayr R., and R. Sarren. 2015. Sensitivity to 

Hydrocarbons and Baselines of Exposure in Marine Birds on the Chukchi and Beaufort Seas. 

Coastal Marine Institute Annual Review, Anchorage, AK, January 23, 2015 (presentation).

Riddle A.E., Hollmén T.E., Suydam R., and R Stimmelmayr. 2014. Assessing Hydrocarbon 

Sensitivity and Establishing Current CYP1A Baselines in Select Marine Birds and Waterfowl of 

the Beaufort and Chukchi Seas. Alaska Marine Science Symposium, Anchorage, AK, January 

19–23, 2015 (poster).

Riddle A.E., Hollmén T.E., Suydam R., and R Stimmelmayr. 2014. Assessing Hydrocarbon 

Sensitivity and Establishing Baselines of Current Exposure in Marine Birds and Waterfowl on 

the Beaufort and Chukchi Seas. Alaska SeaLife Center Colloquium, Seward, AK, October 29, 

2014 (presentation).

Riddle A.E., Hollmén T.E., Suydam R., and R Stimmelmayr. 2014. Assessing Hydrocarbon 

Sensitivity and Establishing Baselines of Current Exposure in Marine Birds on the Beaufort and 

Chukchi Seas. Arctic Science Conference, Fairbanks, AK, September 27, 2014 (poster). 
32

Riddle A.E., Hollmén T.E., Suydam R., and R Stimmelmayr. 2014. Sensitivity to Hydrocarbons 

and Baselines of Exposure in Marine Birds on the Chukchi and Beaufort Seas. Alaska Marine 

Science Symposium, Anchorage, AK, January 20–24, 2014 (poster). 

Riddle A.E. and T.E. Hollmén. 2014. Sensitivity to Hydrocarbons and Baselines of Exposure in 

Marine Birds on the Chukchi and Beaufort Seas. Coastal Marine Institute Annual Review,

Fairbanks, AK, January 15, 2014 (presentation).
33

REFERENCES

Brendler-Schwaab, S.Y., P. Schmezer, U. Liegiebel, S. Weber, K. Michalek, A. Tompa, and B.L

Pool-Zobel. 1994. Cells of different tissues for in vitro and in vivo studies in

toxicology: Compilation of isolation methods. Toxicol. In Vitro 8(6):1285–1302.

Dickson, D.L. and H.G. Gilchrist. 2000. Status of marine birds on the southeastern Beaufort Sea.

Arctic 55(1):46–58.

Earnst, S.L., R.A. Stehn, R.M. Platte, W.W. Larned, and E.J. Mallek. 2005. Population size and

trend in yellow-billed loons in Northern Alaska. The Condor 107:289–304.

Esler, D. 2008. Quantifying temporal variation in harlequin duck cytochrome P4501A induction.

Exxon Valdez Oil Spill Trustee Council Gulf Ecosystem Monitoring and Research

Project Final Report (GEM Project 050777). Centre for Wildlife Ecology, Simon Fraser

University, British Columbia.

Esler, D., K.A. Trust, B.E. Ballachey, S.A. Iverson, T.L. Lewis, D.J. Rizzolo, D.M. Mulcahy,

A.K. Miles, B.R. Woodin, J.J. Stegeman, J.D. Henderson, and B.W. Wilson. 2010.

Cytochrome P4501A biomarker indication of oil exposure in harlequin ducks up to 20

years after the Exxon Valdez oil spill. Environ. Toxicol. Chem. 29(5):1138–1145.

Federal Register. 1993. Final rule to list the spectacled eider as threatened. Fed. Regist.

58:27474–27480.

Federal Register. 1997. Endangered and threatened wildlife and plants: threatened status for the

Alaska breeding population of the Steller’s eider. Fed. Regist. 62:31748–31757.

Finney, D.J. 1978. Statistical methods in biological assay, 3rd ed. Charles Griffin & Company,

London, 508 pp.

Flint, P. L., M. R. Peterson, and J. B. Grand. 1997. Exposure of Spectacled Eiders and other diving ducks

to lead in western Alaska. Can. J. Zool. 75(3): 439–443.

Freshney, R. I. 2000. Culture of animal cells: A manual of basic technique, 4th ed. Wiley-Liss,

Inc., New York, 577 pp.

Gottschalk, P.G. and J.R. Dunn. 2005. The five-parameter logistic: A characterization and

comparison with the four-parameter logistic. Anal. Biochem. 343:54–65.

Hahn, M.E., B.L. Woodward, J.J. Stegeman, and S.W. Kennedy. 1996. Rapid assessment of

induced cytochrome P4501A protein and catalytic activity in fish hepatoma cells grown

in multiwell plates: Response to TCDD, TCDF, and two planar PCBS. Environ. Toxicol.

Chem. 15(4):582–591. 

Hodson, P.V., S. Efler, J.Y. Wilson, A. El-Shaarawi, M. Maj, and T.G. Williams. 1996.

Measuring the potency of pulp mill effluents for induction of hepatic mixed

function oxygenase activity in fish. J. Toxicol. Environ. Health 49(1):83–110.
34

Hollmén, T., J.C. Franson, M. Kilpi, D.E. Docherty, W.R. Hansen, and M. Hario. 2002. Isolation

and characterization of a reovirus from common eiders (Somateria mollissima) from

Finland. Avian Dis. 46:478–484.

Hollmén, T., J.C. Franson, P.L. Flint, J.B. Grand, R.B. Lanctot, D.E. Docherty, and H.M.

Wilson. 2003. An adenovirus linked to mortality and disease in long-tailed ducks in

Alaska. Avian Dis. 47:173–179.

Hollmén T.H., K. Springman, and A.E. Riddle. 2008. Evaluating injury to harlequin ducks

(Histrionicus histrionicus) caused by sublethal hydrocarbon exposure in Prince William

Sound using species specific cell lines. EVOSTC Annual Report Sept. 1, 2008. Project

080839.

Hollmén T.H., K. Springman, and A.E. Riddle. 2009. Evaluating injury to harlequin ducks

(Histrionicus histrionicus) caused by sublethal hydrocarbon exposure in Prince William

Sound using species-specific cell lines. EVOSTC Annual Report Sept. 1, 2009. Project

090839.

Hollmén T.H., K. Springman, and A.E. Riddle. 2010. Evaluating injury to harlequin ducks

(Histrionicus histrionicus) caused by sublethal hydrocarbon exposure in Prince William

Sound using species-specific cell lines. EVOSTC Annual Report Sept. 1, 2010. Project

10100839.

Hollmén T.H., K. Springman, and A.E. Riddle. 2011. Evaluating injury to harlequin ducks

(Histrionicus histrionicus) caused by sublethal hydrocarbon exposure in Prince William

Sound using species-specific cell lines. EVOSTC Annual Report Sept. 1, 2011. Project

10100839.

Hollmén T.H., K. Springman, and A.E. Riddle. 2012. Evaluating injury to harlequin ducks

(Histrionicus histrionicus) caused by sublethal hydrocarbon exposure in Prince William

Sound using species-specific cell lines. EVOSTC Annual Report Sept. 1, 2012. Project

10100839.

Incardona J.P., M.G. Carls, H. Teraoka, C.A. Sloan, T.K. Collier, and N.L. Scholz. 2005. Aryl

hydrocarbon receptor-independent toxicity of weathered crude oil during fish

development. Environ. Health Perspect. 113(12):1755–1762.

Kennedy, S.W., A. Lorenzen, S.P. Jones, M.E. Hahn, and J.J. Stegeman. 1996. Cytochrome

P4501A induction in avian hepatocyte cultures: a promising approach for predicting the

sensitivity of avian species to toxic effects of halogenated aromatic hydrocarbons.

Toxicol. Appl. Pharmacol. 141:214–230.

Lee, Y. Z., F.A. Leighton, D.B. Peakall, R.J. Norstrom, P.J. O’Brien, J.F. Payne, and A.D.

Rahimtul. 1985. Effects of ingestion of Hibernia and Prudhoe Bay crude oils on hepatic

and renal mixed function oxidase in nestling herring gulls (Larus argentatus). Environ.

Res. 36:248–255.
35

Lorenzen, A., J.L. Shutt, and S.W. Kennedy. 1997. Sensitivity of common tern (Sterna hirundo)

embryo hepatocyte cultures to CYP1A induction and porphyrin accumulation by

halogenated aromatic hydrocarbons and common tern egg extracts. Arch. Environ.

Contam. Toxicol. 32:126–134.

Miles, A.K., P.L. Flint, K.A. Trust, M.A. Ricca, S.E. Spring, D.E. Arietta, T. Hollmén, and B.W.

Wilson. 2007. Polycyclic aromatic hydrocarbon exposure in Steller’s eiders (Polysticta

stelleri) and harlequin ducks (Histrionicus histrionicus) in the eastern Aleutian Islands,

Alaska, USA. Environ. Toxicol. Chem. 26(12):2694–2703.

Oppel, S., D.L. Dickson, and A.N. Powell. 2009. International importance of the eastern Chukchi

Sea as a staging area for migrating king eiders. Polar Bio. 32:775–783.

Perkins, M., L. Ferguson, R.B. Lanctot, I.J. Stenhouse, S. Kendall, S. Brown, H.R. Gates, J.O.

Hall, K. Regan, and D.C. Evers. 2016. Mercury exposure and risk in breeding and staging

Alaskan shorebird. The Condor 118:571–582.

Short, J.F., K.R. Springman, M.R. Lindeberg, L.G. Holland, M.L. Larsen, C.A. Sloan, C. Khan,

P.V. Hodson, and S.D. Rice. 2008. Semipermeable membrane devices link-site specific

contaminants to effects: PART II- A comparison of lingering Exxon Valdez oil with other

potential sources of CYP1A inducers in Prince William Sound, Alaska. Mar. Environ.

Res. 66(5):487–498.

Springman, K.R., J.W. Short, M.R. Lindeberg, J.M. Maselko, C. Khan, P.V. Hodson, and S.D.

Rice. 2008. Semipermeable membrane devices link site-specific contaminants to effects:

Part I- Induction of CYP1A in rainbow trout from contaminants in Prince William Sound,

Alaska. Mar. Environ. Res. 66(5):477–486.

Suydam, R.S., D.L. Lynne, J.B. Fadely, and L.T. Quakenbush. 2000. Population declines of the

king and common eiders of the Beaufort Sea. The Condor 102:219–222.

Trust, K.A., D. Esler, B.R. Woodin, and J.J.Stegeman. 2000. Cytochrome P450 1A induction in

sea ducks inhabiting nearshore areas of Prince William Sound, Alaska. Mar. Pollut. Bull.

40(5):397–403.

Trust, K.A., K.T. Rummel, A.M. Scheuhammer, I.L. Brisbin, Jr., and M.J. Hooper. 2000b.

Contaminant exposure and biomarker responses in spectacled eiders (Somateria fischeri)

from St. Lawrence Island, Alaska. Arch. Environ. Contam. Toxicol. 38:107–113.

Wilson, H.M., J.L. Oyen, and L. Sileo. 2004. Lead shot poisoning of a Pacific Loon in Alaska.

J. Wildl. Dis. 40(3):600–602.
36

APPENDICES

Appendix A: Number of EROD assays performed for species/dose combinations.

Table A1: Number of EROD assays for each species and BNF doses at 24-hour dose exposure. Some 

replicates may have been removed from analysis due poor culture quality. COEI=common eider, 

COMU=common murre, goose=domestic goose, GWFG=greater white-fronted goose, LTDU=long-tailed 

duck, MALL=mallard, STEI=Steller’s eider, TUPU=tufted puffin.

Dose Species Number of 

dose repeats 

BNF 0.5 μM COEI 2

GWFG 2

LTDU 1

MALL 3

STEI 4

TUPU 1

BNF 1.0 μM COEI 2

COMU 2

Goose 1

GWFG 2

LTDU 1

MALL 7

STEI 6

TUPU 1

BNF 1.5 μM GWFG-tule 1

MALL 1

BNF 2.0 μM COEI 2

COMU 1

GWFG 2

LTDU 1

MALL 6

STEI 4

TUPU 1

BNF 2.5 μM MALL 1

BNF 5.0 μM COEI 1

GWFG 2

MALL 2

STEI 4

BNF 10.0 μM MALL 1
37

Table A2: Number of EROD assays for each species and chrysene doses at 24-hour dose 

exposure. Some replicates may have been removed from analysis due poor culture quality. 

COEI=common eider, COMU=common murre, goose=domestic goose, GWFG=greater whitefronted goose, HOPU=horned puffin, LTDU= long-tailed duck, MALL=mallard, STEI=Steller’s 

eider, TUPU=tufted puffin.

Dose Species

Number 

of dose 

repeats Dose Species

Number of 

dose 

repeats 

chrysene 

0.5 μM

COEI 4

chrysene 

2.0 μM

COEI 3

COMU 2 COMU 4

GWFG 3 Goose 1

LTDU 1 GWFG 3

MALL 6 HOPU 1

STEI 5 LTDU 1

TUPU 1 MALL 10

chrysene 

1.0 μM

Brant 1 STEI 7

COEI 5 TUPU 1

COMU 7

chrysene 

2.5 μM MALL 1

Goose 1

chrysene 

3.0 μM

COEI 1

GWFG 3 LTDU 1

HOPU 1 STEI 3

KIEI 1

chrysene 

5.0 μM

COEI 1

LTDU 2 GWFG 3

MALL 10 HOPU 1

SPEI 4 LTDU 1

STEI 12 MALL 3

TUPU 1 STEI 4

chrysene 

1.5 μM

GWFG 1

chrysene 

10.0 μM MALL 1

LTDU 1

MALL 4

SPEI 1

STEI 2
38

Table A3: Number of EROD assays for each species and phenathrene doses at 24-hour dose exposure. 

Some replicates may have been removed from analysis due poor culture quality. MALL= mallard, and 

STEI= Steller’s eider.

Dose Species Number of dose 

repeats 

Dose Species Number of dose 

repeats 

phenathrene 

0.5 μM

MALL 1 phenathrene 5.0

μM

GWFG 1

STEI 2 STEI 1

phenathrene 

1.0 μM

GWFG 1 phenathrene 

10.0 μM

GWFG 1

MALL 1 STEI 2

STEI 4 phenathrene 

50.0 μM

GWFG 1

phenathrene 

2.0 μM

MALL 1 STEI 2

STEI 2

Table A4: Number of EROD assays for each species and North Slope crude oil doses at 24-hour dose 

exposure. Some replicates may have been removed from analysis due poor culture quality. 

COEI=common eider, COMU=common murre, MALL=mallard, STEI=Steller’s eider, TUPU=tufted 

puffin

Dose Species

Number of dose 

repeats Dose Species

Number of dose 

repeats 

oil 0.5

μL

GWFG 1 oil #1

20 μL 1:1 oil:DMSO 

w/2 mL media

COEI 1

STEI 2 MALL 1

oil 1 μL

COEI 4 STEI 3

COMU 1

oil #2

10 μL 1:1 oil:DMSO

w/2 mL media

COEI 1

GWFG 2 MALL 1

MALL 2 STEI 4

STEI 5 TUPU 1

TUPU 1

oil #4

5 μL 1:1 oil:DMSO 

wi/2 mL media

COEI 1

oil 5 μL

COEI 4 MALL 2

COMU 3 STEI 4

GWFG 1 TUPU 1

MALL 1

oil:DMSO 1:1 1 μL

MALL 2

STEI 6 STEI 3

TUPU 1 TUPU 1

oil 10 μL

COEI 4 oil:DMSO 10:1 1 μL STEI 2

COMU 1 oil:DMSO 3:1 1 μL STEI 2

GWFG 1 oil:DMSO 5:1 1 μL STEI 2

MALL 1

STEI 5

oil 20 μL GWFG 1

STEI 2
39

Appendix B: CPE results by species/dose combinations.

Table B1: CPE results in Steller’s eider to different concentrations of chrysene doses with 24-hour dose 

exposure. Results from 2013-2015 for each dose were combined. Semiquantitative response grade 0-4 

(0=none to 4=100 % effect). Cell and carrier material (DMSO) controls are also included.

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

ization

Vacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider chrysene 0.5 μM 20-90% 0 0 0-2 0 1 0

Steller's 

eider chrysene 1.0 μM 40-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider chrysene 1.5 μM 10-40% 0 0 1-2 0 1-2 0

Steller's 

eider chrysene 2.0 μM 10-70% 0 0 1-2 0 1-2 0

Steller's 

eider chrysene 3.0 μM 20-60% 0 0 1-2 1-2 1 0

Steller's 

eider chrysene 5.0 μM 20-80% 0 1 1-2 0 1-3 0

Steller's 

eider DMSO 1:3 40-90% 0 0-2 0-2 0 0-1 0

Steller's 

eider cells none 30-90% 0 0-1 0-2 0 0-1 0

Table B2: CPE results in Steller’s eider to different concentrations of BNF doses with 24-hour dose 

exposure. Results from 2013-2015 for each dose were combined. Semiquantitative response grade 0-4 

(0=none to 4=100 % effect). Cell and carrier material (ethanol) controls are also included. 

Species Dose Dose 

Concentration

Sheet 

Confluency

GranularizationVacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider BNF 0.5 μM 30-70% 0 0-1 1-2 0 0-2 0

Steller's 

eider BNF 1.0 μM 20-80% 0 0-1 0-3 0 0-2 0

Steller's 

eider BNF 2.0 μM 20-70% 0 0-1 1-3 0 0-2 0

Steller's 

eider BNF 5.0 μM 50-60% 0 0-1 1-3 0 0-2 0

Steller's 

eider

ethano

l 1:1 60-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider cells none 30-90% 0 0-1 0-2 0 0-1 0
40

Table B3: CPE results in Steller’s eider to different concentrations of phenanthrene doses with 24-hour

dose exposure. Results from 2015 for each dose were combined. Semiquantitative response grade 0-4 

(0=none to 4=100 % effect). Cell and carrier material (ethanol) controls are also included. 

Table B4: CPE results different amount of neat Alaska North Slope crude oil dose and cell control with 

24-hour dose exposure in Steller’s eider. Results from 2015 for each dose were combined. 

Semiquantitative response grade 0-4 (0=none to 4=100 % effect). 

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

ization

Vacuolar--

ization

Rounded up 

(non-viable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider

NS crude 

oil

0.5 μL 50-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider

NS crude 

oil

1.0 μL 70-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider

NS crude 

oil

5.0 μL 50-80% 0 0-1 0-3 0 0-1 0

Steller's 

eider

NS crude 

oil

10.0 μL 50-80% 0 0-1 1-3 0 0-1 0

Steller's 

eider

NS crude 

oil

20.0 μL 50-70% 0 0-1 2 0 0 0

Steller's 

eider

cells none 30-90% 0 0-1 0-2 0 0-1 0

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

ization

VacuolarizationRounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalt

-ing

Steller's 

eider

phenanthrene 0.5 μM 60-80% 0 0 1-3 0 1 0

Steller's 

eider

phenanthrene 1.0 μM 50-80% 0 0-1 1-3 0 0-2 0

Steller's 

eider

phenanthrene 2.0 μM 50-80% 0 0 3 1-2 0 0

Steller's 

eider

phenanthrene 5.0 μM 50-60% 0 0 3-4 0 2 0

Steller's 

eider

phenanthrene 10.0 μM obscured by 

debris 0 0 0 0 0 3-4

Steller's 

eider

phenanthrene 50.0 μM obscured by 

debris 0 0 0 0 0 3-4

Steller's 

eider ethanol 1:1 60-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider cells none 30-90% 0 0-1 0-2 0 0-1 0
41

Table B5: CPE results to different amount of media diluted Alaska North Slope crude oil dose and cell 

and media control with 24-hour dose exposure in Steller’s eider. 100 μL of each diluted dose was added 

to the well. Doses consisted of: #1 20 μL 1:1 oil:DMSO with 2 mL media, #2 10 μL 1:1 oil:DMSO with 2

mL media, #4 5 μL 1:1 oil:DMSO with 2 mL media. Semiquantitative response grade 0-4 (0=none to 

4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

ization

Vacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider

NS 

crude 

oil

#1 10-70% 0 0 3-4 0 2-3 0

Steller's 

eider

NS 

crude 

oil

#2 60-70% 0 0-1 1-3 0 1-2 0

Steller's 

eider

NS 

crude 

oil

#4 0-80% 0 0-1 1-2 0 1-2 0

Steller's 

eider

cells none 30-90% 0 0-1 0-2 0 0-1 0

Table B6: CPE results to different amount of DMSO diluted Alaska North Slope crude oil doses and cell 

and media control with 24-hour dose exposure in Steller’s eider. Semiquantitative response grade 0-4 

(0=none to 4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

zation

Vacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider

NS 

crude 

oil

oil:DMSO 

1:1

70-80% 0 0 0-1 0 2-4 0

Steller's 

eider

NS 

crude 

oil

oil:DMSO 

3:1

10-50% 0 0 1 0 1 0

Steller's 

eider

NS 

crude 

oil

oil:DMSO 

5:1

10-50% 0 0 1 0 1 0

Steller's 

eider

NS 

crude 

oil

oil:DMSO 

10:1

10-50% 0 0 1 0 1 0

Steller's 

eider

cells none 30-90% 0 0-1 0-2 0 0-1 0
42

Table B7: CPE results in Steller’s eider to 1.0 μM chrysene dose with 12, 24, and 36-hour dose exposure. 

Semiquantitative response grade 0-4 (0=none to 4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular--

ization

Vacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Steller's 

eider

12hrcellsnone 80-90% 0 0 1-2 0 0-1 0

Steller's 

eider

24hrcellsnone 60-90% 0 0-1 0 0-2 0-1 0

Steller's 

eider

36hrcellsnone 60-90% 0 0-1 0-2 0 0 0

Steller's 

eider

12hrchrysene1.0 μM 70-80% 0 0 1-2 0 0-1 0

Steller's 

eider

24hrchrysene1.0 μM 50-80% 0 0-1 1-2 0 0-1 0

Steller's 

eider

36hrchrysene1.0 μM 50-90% 0 0-2 0-2 0 0-1 0

Steller's 

eider

12hrDMSO1:3 70-80% 0 0 1-2 0 0-1 0

Steller's 

eider

24hrDMSO1:3 50-80% 0 0-1 0-2 0 0-1 0

Steller's 

eider

36hrDMSO1:3 50-90% 0 0-2 0 0-2 0-1 0

Table B8: CPE results in tufted puffin to different concentrations of chrysene doses with 24-hour dose 

exposure. Cell and carrier material (DMSO) controls are also included. Semiquantitative response grade 

0-4 (0=none to 4=100 % effect).

Species Dose Dose

Concentration

Sheet 

Confluency

Granular--

ization

Vacuolar--

ization

Rounded up 

(non-viable)

Cytoplasmic 

Swelling

Debris Asphalting

Tufted 

puffin

chrysen

e

0.5 μM 70-80% 0 0 1 0 1 0

Tufted 

puffin

chrysen

e

1.0 μM 70-80% 0 0 1 0 1 0

Tufted 

puffin

chrysen

e

2.0 μM 70-80% 0 0 1 0 1 0

Tufted 

puffin DMSO 1:3 70-80% 0 0 1 0 1 0

Tufted 

puffin cells none 70-80% 0 0 1 0 1 0
43

Table B9: CPE results in tufted puffin to different concentrations of BNF doses with 24-hour dose 

exposure. Cell and carrier material (ethanol) controls are also included. Semiquantitative response grade 

0-4 (0=none to 4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

GranularizationVacuolarizationRounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Tufted puffin BNF 0.5 μM 70-80% 0 0 1 0 1 0

Tufted puffin BNF 1.0 μM 70-80% 0 0 1-2 0 1 0

Tufted puffin BNF 2.0 μM 70-80% 0 0 1-2 0 1 0

Tufted puffin ethanol 1:1 70-80% 0 0 1 0 1 0

Tufted puffin cells none 70-80% 0 0 1 0 1 0

Table B10: CPE results in ten marine bird species and mallard control to 1.0 μM chrysene dose with 24-

hour dose exposure. Results from 2013-2016 for each species were combined. Semiquantitative response 

grade 0-4 (0=none to 4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

GranularizationVacuolarizationRounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Brant chrysene 1.0 μM 40% 1 0 0 0 1 0

Common eider chrysene 1.0 μM 70-100% 0 0-3 1-2 0 0-1 0

Common 

murre chrysene 1.0 μM 20-70% 0 0-1 1-3 0 0-2 0

Goose chrysene 1.0 μM 20-80% 0-1 1-3 0-1 0 0-1 0

Greater whitefronted goose chrysene 1.0 μM 10-25% 0 1 1 0 1 0

Horned puffin chrysene 1.0 μM 40-50% 0 0 0 0 0 0

King eider chrysene 1.0 μM 30% 0 0 2-3 0 1 0

Long-tailed 

duck chrysene 1.0 μM 40-50% 0 0 1-2 0 0 0

Mallard chrysene 1.0 μM 10-95% 0-2 0-3 0-3 0 0-1 0

Spectacled 

eider chrysene 1.0 μM 15-50% 0 0 0-2 0 0-2 0

Steller's eider chrysene 1.0 μM 40-80% 0 0-1 0-2 0 0-1 0

Tufted puffin chrysene 1.0 μM 70-80% 0 0 1 0 1 0
44

Table B11: CPE results in six marine bird species and mallard control to 1.0 μM BNF dose with 24-hour 

dose exposure. Results from 2013-2016 for each species were combined. Semiquantitative response grade 

0-4 (0=none to 4=100 % effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

GranularizationVacuolarizationRounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Common eider BNF 1.0 μM 70-80% 0 1-3 1-2 0 0 0

Common murre BNF 1.0 μM 20-80% 0 0 1-2 0 1-2 0

Goose BNF 1.0 μM 15-80% 0-1 0 0-1 0 1 0

Greater whitefronted goose BNF 1.0 μM 10% 0 0 1-2 0 1 0

Long-tailed 

duck BNF 1.0 μM 40% 0 0 1-2 0 0 0

Mallard BNF 1.0 μM 10-90% 0-2 0-3 1-3 0 0-1 0

Steller's eider BNF 1.0 μM 20-80% 0 0-1 0-3 0 0-2 0

Tufted puffin BNF 1.0 μM 70-80% 0 0 1-2 0 1 0

Table B12: CPE results to 1.0 μL neat Alaska North Slope crude oil dose with 24-hour dose exposure in 

four target species and one control species. Semiquantitative response grade 0-4 (0=none to 4=100 % 

effect).

Species Dose Dose 

Concent

ration

Sheet 

Confluency

GranularizationVacuolarizationRounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Common 

eider

NS crude 

oil 1.0 μL 70-100% 0 1-3 1-2 0 0 0

Common 

murre

NS crude 

oil 1.0 μL 40-50% 0 0 3-4 0 0 0

Greater 

white-fronted 

goose

NS crude 

oil 1.0 μL 10% 0 0 1-2 0 1 0

Mallard NS crude 

oil 1.0 μL 80-90% 0 0 1 0 1 0

Steller's eider NS crude 

oil 1.0 μL 70-80% 0 0-1 0-2 0 0-1 0

Tufted puffin NS crude 

oil 1.0 μL 70-80% 0 0 2 0 1 0
45

Table B13: CPE results to 5.0 μL neat Alaska North Slope crude oil dose with 24-hour dose exposure in 

four target species and one control species. Semiquantitative response grade 0-4 (0=none to 4=100 % 

effect).

Species Dose Dose 

Concentration

Sheet 

Confluency

Granular-

-ization

Vacuolar--

ization

Rounded 

up (nonviable)

Cytoplasmic 

Swelling

Debris Asphalting

Common 

eider

NS crude 

oil 5.0 μL 70-100% 0 1-3 1-2 0 0 0

Common 

murre

NS crude 

oil 5.0 μL 20-50% 0 0 2-4 0 1 0

Greater 

whitefronted 

goose

NS crude 

oil 5.0 μL 10% 0 0 1-2 0 1 0

Mallard NS crude 

oil 5.0 μL 90% 0 1-2 1 0 1-2 0

Steller's 

eider

NS crude 

oil 5.0 μL 50-80% 0 0-1 0-3 0 0-1 0

Tufted puffin NS crude 

oil 5.0 μL 70-80% 0 0 2-3 0 1 0
46

Appendix C: Statistical analysis of EROD results for DMSO and ethanol controls.

Figure C1: Statistical analysis of tested species DMSO control EROD results by estimated percent of cell 

coverage from 10-95% (i.e., 10=10% cell coverage in the assay well). Assay time in minutes is on the xaxis and fluorescence on the y-axis. Real data is represented in dots, the solid line is the estimated 

response trend over time, and the shaded area is the 95% confidence interval. Species abbreviations:

brant-brant, coei-common eider, comu-common eider, goose-domestic goose, gwfg-greater white-fronted 

goose, hopu-horned puffin, kiei-king eider, ltdu-long-tailed duck, mall-mallard, spei-spectacled eider, 

stei-Steller’s eider, tule-domestic tule goose, tupu-tufted puffin.
47

Figure C2: Statistical analysis of tested species ethanol control EROD results by estimated percent of cell 

coverage from 10-95% (i.e., 10=10% cell coverage in the assay well). Assay time in minutes is on the xaxis and fluorescence on the y-axis. Real data is represented in dots, the solid line is the estimated 

response trend over time. Species abbreviations: coei-common eider, comu-common eider, gwfg-greater 

white-fronted goose, ltdu-long-tailed duck, mall-mallard, stei-Steller’s eider, tupu-tufted puffin.
48

Appendix D: Project images.

Eggs from various species incubating. Common murre egg shells.

Pellet of liver cells during the extraction

process.

Culture of Steller’s eider liver cells.
49

Snow machine with sled to haul gear to the 

snow blind. Barrow, AK, May 2015.

Ann Riddle-Berntsen (UAF CFOS Graduate Student) 

and Robert Sarren (NSB-DWM)

in a snow blind near Barrow, AK, May 2015.

Goose decoys used during spring hunts. Barrow, 

AK, May 2015.

Robert Sarren (NSB-DWM) weighing a common eider 

post mortem. Barrow, AK, October 2014.

Hunters wait in their cars for flocks of eiders. 

Barrow, AK, August 2015. Field truck loaded with supplies including a 20 L

liquid nitrogen dewar, tote with sampling supplies, 

and a kayak to retrieve birds that fall into the water. 

Barrow August 2015.
50

5 L liquid nitrogen dewar attached to the back of 

the 4-wheeler. Barrow, AK, August 2014.

Robert Sarren and Ryan Klimstra (both from NSBDWM) looking for greater white-fronted geese near 

Barrow, AK, August 2014.

A flock of greater white-fronted geese near 

Barrow, AK, August 2015.

Laboratory station in NSB-DWM bunk house. We 

used this space to process blood and organize samples 

and supplies post hunts. Barrow, AK, August 2014.

Looking for flocks of eiders near Barrow, AK, August 2015.

.
As the Nation’s principal conservation agency, the Department of the Interior has 

responsibility for most of our nationally owned public lands and natural 

resources. This includes fostering the sound use of our land and water 

resources, protecting our fish, wildlife and biological diversity; preserving the 

environmental and cultural values of our national parks and historical places; and 

providing for the enjoyment of life through outdoor recreation.The Department 

assesses our energy and mineral resources andworks to ensure that their 

development is in the best interests of all our people by encouraging stewardship 

and citizen participation in their care. The Department also has a major 

responsibility for American Indian reservation communities and for people who 

live in island communities.

The Bureau of Ocean Energy Management 

The Bureau of Ocean Energy Management (BOEM) works to manage the 

exploration and development of the nation's offshore resources in a way that 

appropriately balances economic development, energy independence, and 

environmental protection through oil and gas leases, renewable energy 

development and environmental reviews and studies.

The Department of the Interior Mission