bluuebunny/crossref_metadata_2025 huggingface dataset:
Annual subsurface transport of a red tide dinoflagellate to its bloom area: Water circulation patterns and organism distributions in the Chesapeake Bay 1
Authors: Tyler Mary Altalo , Seliger H. H.
Published: March 2010

An annual, long range, subsurface transport of Prorocentrum mariae‐lebouriae, from the mouth of the Chesapeake Bay to its bloom area in the upper bay, a distance of 240 km, is described and completely documented. Prorocentrum in surface outflowing waters at the mouth of the bay is recruited in late winter into more dense inflowing coastal waters. Strong stratification produced by late winter–early spring surface runoff results in the development of a stable pycnocline. Prorocentrum, now in northward‐flowing bottom waters, is retained in these bottom waters. It accumulates in a subsurface concentration maximum below the pycnocline and is transported northward to reach its bloom area in the Patapsco River and north of the Bay Bridge by late spring. The rapidly decreasing depth of the upper bay causes the pycnocline to rise, mixing the previously light‐limited Prorocentrum and its nutrient‐rich bottom waters to the surface, where rapid growth ensues. Once the dinoflagellate is in surface waters, positive phototaxis, combined with both wind‐ and tide‐driven surface convergences, produce dense surface patches or red tides. Prorocentrum is effectively retained in the bay until late winter by sequential inoculation into the tributary estuaries on the western shore, which exchange relatively slowly with bay waters. By late winter the annual cycle is complete. Prorocentrum is again in surface waters at the mouth of the bay where it is reintroduced into northward‐flowing bottom waters. The mechanisms described provide a key to understanding the origins of subsurface chlorophyll maxima and the delivery of toxic dinoflagellates to coastal bloom areas.
The bio‐optical state of ocean waters and remote sensing 1
Authors: Smith Raymond C. , Baker Karen S.
Published: March 2010

The diffuse attenuation coefficient for irradiance, KT, is a physical measure of the bio‐optical state of ocean waters. From an analysis of irradiance, KT, and pigment concentration, the specific attenuation due to chlorophyll‐like pigments is found to be 0.016 ± 0.003 [m−1 (mg pigment m−3)−1]. The bio‐optical state of ocean waters can be remotely sensed by spacecraft sensors. KT is readily measured at sea and is highly correlated with and dependent on the chlorophyll‐like pigment concentration, CK. This pigment concentration and KT provide a measure of the fraction of radiant energy attenuated by phytoplankton. This fraction, in turn, is closely related to the production equations formulated by Bannister and can be directly incorporated into a general theory of phytoplankton dynamics. CK may also be used as an index of primary productivity. The determination of the bio‐optical state of ocean waters by surface vessel provides direct information concerning the productivity of these waters; to the extent that the bio‐optical state can be determined by satellite, it may be possible to examine important parameters of the marine ecosystem rapidly and repeatedly.
Relationships between vertical migration and diet in four species of euphausiids 1
Authors: Hu Vernon J. H.
Published: March 2010

Diel changes in stomach weight of euphausiids showed a close relationship between the inferred increase of feeding at night and strong vertical migration in four species. Thysanopoda aequalis and Thysanopoda monacantha, species with a small percentage (4 and 13%) of depth overlap between their day and night vertical distributions (i.e. large diel vertical migration), exhibited a marked increase in stomach weight at night. Thysanopoda pectinata (39% overlap), a moderate vertical migrator, showed a constant stomach weight throughout day and night. Nematobrachion sexspinosus (56% overlap), a very weak or nonmigrator, showed increased stomach weight during the day. Increases in stomach weight at night were accompanied by an increase in fluorescence and the amount of phytoplankton remains found in the stomach, but neither was found in the species which did not show increased stomach weight at night.
Anaerobic microbial community metabolism in Spartina alterniflora soil 1, 2
Authors: Christian R. R. , Wiebe W. J.
Published: March 2010

The anaerobic uptake of [14C]glucose was used as an index of potential microbial activity in the soils of a Spartina alterniflora salt marsh. The turnover times of glucose were consistently faster in the soils where tall S. alterniflora grew along a creekbank than in the high marsh soils where S. alterniflora productivity was lower; this difference was magnified with increased depth. The distribution of label, followed through CO2, particulate, and ether‐soluble fractions indicated rapid recycling in the soil of the tall S. alterniflora marsh. In an experiment designed to assess the effects of tidal inundation on the activity of the microbial community in the tall S. alterniflora marsh soils, no consistent changes in glucose uptake or ATP concentration were evident after 2 months of restricting water movement. No direct link of tidal inundation with the microbial community was observed.
Seven problems in bubble and jet drop researches 1
Authors: Blanchard Duncan C. , Syzdek Lawrence D.
Published: March 2010

Four of the problems deal with the mechanics of bubble production and bursting, and the collection and sizing of jet drops; three concern the transfer of the bacterium Serratia marcescens from bursting bubbles to jet drops. The problem of producing bubbles of a specified size from glass capillary tips is overcome by paying careful attention to tip geometry. Problems associated with bubble bursting have not been solved, but it is believed that they are caused by small differences in the position of the bubble relative to the interface at the time of bursting. The collection and sizing of jet drops can cause problems, but suggestions are given to overcome them. Of the three problems involving bacteria, only the last appears to have a satisfactory solution. Experiments show that the concentration of bacteria is always highest in the top jet drop of the jet set and decreases progressively in the lower drops, being lowest in the bottom drop. This is in qualitative agreement with the hypothesis of jet drop formation advanced by MacIntyre.
Early diagenesis in transitional sedimentary environments of the White Oak River Estuary, North Carolina 1
Authors: Martens Christopher S. , Goldhaber Martin B.
Published: March 2010

Changes in sedimentary diagenetic processes resulting from the transition from a terrestrial to a marine environment were studied through a series of riverbed cores collected from the White Oak River Estuary. Analyses of interstitial water and associated solid phases reveal systematic geochemical and mineralogical trends over an 18‐km stretch of estuary and river channel related to the transition from a dominantly marine to a dominantly terrestrial setting. The most striking of these trends involves the nature of the metabolic pathways by which bacterial decomposition of organic matter occurs and probable differences in the composition of organic matter. In the riverbed stretches under periodic marine influence, sulfate reduction is a major process, owing to the availability of seawater sulfate. Upstream, however, methane generation becomes more important. Consistent with this trend is a decrease in sedimentary pyrite in methane‐rich sediments. Total inorganic carbon decreases by nearly an order of magnitude upstream, and pH is significantly lower in the terrestrial environment. Chemically reactive products of organic decomposition, such as ammonia and phosphate, are considerably less concentrated in the cores taken farthest from marine influence.
Community plankton respiration in a salt marsh estuary and the importance of macrophytic leachates 1
Authors: Turner R. Eugene
Published: March 2010

Community plankton respiration (CPR) was measured in a Georgia salt marsh tidal creek and estuary. CPR ranged from 94 to 162 g O2 · m−3 · yr−1(234–978 g O2 · m−1 · yr−1) inshore and was much lower in nearby coastal waters. Seasonal changes in CPR are closely associated with changes in temperature in a log‐log manner (R2 = 0.60–0.85) as are many other measurements of metabolic activity in the estuary, including live biomass of Spartina alterniflora. Leaching rates of dissolved organic matter by Spartina during tidal submergence were 200–800 µg C· g dry wt−1 · h−1, depending on salinity and season. The release rate was lower, 21 µg C· g dry wt−1 · h−1, when the plant was not submerged. The plankton community is capable of rapidly and efficiently absorbing this material, which is produced in large enough quantities to account for the observed seasonal changes in CPR.
Bioenergetic and developmental response of a mayfly to thermal variation 1
Authors: Sweeney Bernard W.
Published: March 2010

Egg development, growth, and emergence of Isonychia bicolor were observed in White Clay Creek (Pennsylvania) at ambient temperatures and in fluctuating experimental regimes with diel minima ranging from 12°–12.9°C and maxima between 12° and 20.1°C. Development rate of both eggs and nymphs was correlated positively with increased magnitude of the diel temperature pulse. Adult metamorphosis was most successful in regimes with diel maxima >16°C.

Subimago body size and fecundity for winter generation females were about double those for the summer generation. Reducing spring and summer water temperatures lowered the fecundity of winter and summer subimagoes.

Weight‐specific respiration rates of nymphs measured at 1.4 constant temperatures (range, 1°–21°C) increased with temperature but were inversely related to body size at a given temperature. Metabolic response to short term (1 h) changes in temperature was immediate; thermal acclimation or compensation was not observed.

Energy budgets were calculated for male and female nymphs reared in various thermal regimes. Growth rates, net growth efficiencies, and production:respiration ratios of female nymphs were about twice those of males at all temperatures. Overall net growth efficiencies for I. bicolor averaged 44.16% and P:R ratios 0.84 for the combined sexes.
Chemistry of small Norwegian lakes, with special reference to acid precipitation 1
Authors: Wright Richard F. , Henriksen Arne
Published: March 2010

The concentrations of major ions were determined in 155 representative, small, pristine lakes in southern Norway. The chemistry of these lakes appears to be governed by three factors: atmospheric inputs of seawater salts supply most of the Cl and Na; acid precipitation supplies most of the SO4 and H+; and terrestrial inputs of chemical weathering products account for most of the Ca, Mg, and HCO3.

The interaction of acid precipitation and geologic environment largely explains pH levels in these lakes. Lakes in granitic terrains have low concentrations of major ions, low buffer capacities, and are often acidic (pH < 5) when located in areas subject to acid precipitation. Sulfate is the major anion. Lakes in granitic terrains that do not receive highly acidic precipitation have pH levels >5.5, and bicarbonate is the major anion.
Assimilation of silicic acid by phytoplankton in the Baja California and northwest Africa upwelling systems 1
Authors: Nelson David M. , Goering John J.
Published: March 2010

Rates of silicic acid uptake by natural phytoplankton populations were measured at 31 stations in the region of coastal upwelling off Baja California, and 28 in the upwelling region off northwest Africa, using the stable isotope 30Si. Silicic acid uptake in both systems extended to about twice the depth to which carbon and nitrogen assimilation was observed, and continued at substantial rates throughout the 24‐h day. Kinetic experiments, performed at the two Baja California stations and four northwest Africa stations exhibiting the lowest near‐surface silicic acid concentrations observed, did not show the rate of uptake to be substrate limited. Data on upwelling velocities, nutrient concentrations, and nutrient uptake rates suggest that silicon limitation in the Baja California system was prevented by high rates of silicic acid regeneration resulting from dissolution of diatom silica.
Iron in Maine coastal waters; seasonal variation and its apparent correlation with a dinoflagellate bloom
Authors: Glover Hilary E.
Published: March 2010

During 1975, 12 km south of Boothbay Harbor, soluble iron concentrations in the first 20 m of water were three times greater in October and November than in August and September, while particulate iron concentrations only increased transiently before the fall bloom. Nutrient enrichment experiments and chlorophyll a : cytochrome f1 ratios indicated that low iron concentrations limited phytoplankton populations. In August 1976, 1–4 km from Monhegan Island, increased iron concentrations from land runoff preceded a dinoflagellate bloom.
Measurement of the vertical flux of particulate organic matter with a free‐drifting sediment trap 1
Authors: Staresinic Nick , Rowe Gilbert T. , Shaughnessey Dan , Williams Albert J.
Published: March 2010

Measurements of the vertical flux of particulate organic matter are usually made with moored sediment traps. In situ dye experiments in Buzzards Bay, Massachusetts, suggest that, in a current as low as 15 cm · s−1, the turbulent wake established over the entrance of such a device may severely bias estimation of both the quantity and quality of material settling through the water column, but that a free‐drifting trap is not hampered by this problem. The free‐drifting mode also permits shallow deployments in deep‐water columns, without the problems accompanying deep moorings, and tracking of particular water parcels, such as upwelling plumes.
Spectrophotometric equations: An intercalibration technique 1
Authors: Wartenberg Daniel E.
Published: March 2010

A set of equations is presented for the interconversion of chlorophyll concentrations calculated by any of five sets of trichromatic equations.
Polyphenol inhibition of calcite precipitation in Lake Powell 1
Authors: Reynolds Robert C.
Published: March 2010

Laboratory studies of calcite precipitation kinetics in waters of simulated Lake Powell composition have verified that precipitation occurs by a spiral dislocation growth mechanism. But waters from the lake and laboratory solutions containing tannic acid and plant polyphenols at low and very low levels showed calcite growth rates proportional to the fourth power of the carbonate ion concentration. The results indicate the operation of a surface polynuclear growth process that becomes effective when polyphenol adsorption blocks spiral dislocation growth sites and causes precipitation rates to diminish with increasing polyphenol concentration and to fall drastically as pH is lowered. The effects of these factors are dominant controls on the calcium carbonate geochemistry of Lake Powell. Significant amounts of calcite precipitation occur only in the surface waters of the downstream portion of the reservoir and, even there, only during the warm (6 months) portion of the year.
In situ and laboratory measurements on macroscopic aggregates in Monterey Bay, California 1
Authors: Rent Jonathan D. , Shanks Alan L. , Silver Mary Wilcox
Published: March 2010

The size, distribution, chlorophyll a, and pheopigment content of macroscopic aggregates (marine snow) from the upper 20 m of Monterey Bay, California, are reported. These large particles are not collected intact by traditional oceanographic sampling techniques. In situ SCUBA observations indicated lengths up to 9 cm and concentrations of 2 to 28 aggregates per liter. Aggregates were hand‐collected for laboratory analyses of chlorophyll a and pheopigments. The concentrations of both were significantly higher in aggregates than in the surrounding water. The ratio of pigment concentrations in aggregates to that in the surrounding water ranged from a factor of 4 to 750 for chlorophyll a and from 13 to 5,564 for pheopigments. The aggregates contained up to 8.0% of the total chlorophyll a and up to 64.2% of the total pheopigments in the study area. Underwater observations over 3 years indicate that aggregates are frequently present in the surface waters of Monterey Bay and initial quantitative studies suggest their potential ecological significance as microhabitats and pelagic food sources.
Positive buoyancy through ionic control in the nonmotile marine dinoflagellate Pyrocystis noctiluca Murray ex Schuett 1
Authors: Kahn Norman , Swift Elijah
Published: March 2010

In culture, vegetative cells, which are positively buoyant, have vacuoles that are about 95% of their volume. They may rise at 0–20 cm · h−1 and have cell sap 2.0–3.1 mg · ml−1 less dense than their seawater medium. Isotonic cell sap has SO42− at ⅛th, and Ca2+ and Mg2+ at ½ seawater concentrations (these ions are replaced by NaCl) which accounts for most of its lower density. There were no day to night differences in the concentrations of Na+, K+, Ca2+, Mg2+, or Cl− in cell sap, but cells grown at high light intensities had more K+ and Mg2+ in their cell sap than cells grown in dim light. Nutrient‐replete cells were more positively buoyant than nutrient‐depleted cells. NH4+ stored in cell sap of nutrient‐replete cells lowered its density by about 0.2 mg · ml−1. Vegetative cells killed with HgCl2 sank at 30–40 cm · h−1. In nature, nutrients and light intensity may act as counteracting factors to keep Pyrocystis noctiluca suspended at a depth favorable for growth.
Photosynthetic rates of marine algae as a function of inorganic carbon concentration
Authors: Caperon J. , Smith D. F.
Published: March 2010

The effect of inorganic carbon concentration on the rates of carbon fixation by mixed phytoplankton and by three algal species in culture was examined. The inorganic carbon concentrations resulting in half‐maximal fixation rates ranged from 4.3–5.3 mg C · liter−1 for phytoplankton and from 0.8–3.0 for the axenic algal cultures. The applicability of the Michaelis‐Menten equation to experimental systems of n species is demonstrated.
Dependence of light‐saturated rates of algal photosynthesis on intracellular concentrations of phosphorus
Authors: Senft W. Herbert
Published: March 2010

Specific rates of photosynthesis at saturating irradiances (Popt) by laboratory populations of Chlorella and Anabaena depend on intracellular phosphorus (Q). A hyperbolic model of the form Popt =Popts (1−KQ/Q) is used to describe this relationship for three measurements of biomass (cell number, cell volume, and chlorophyll a). Chlorophyll a provides the most adequate fit to the model. When chlorophyll a is used as the measure of population size, both the maximal specific rate of photosynthesis (Popts) and the subsistence cell quota (KQ) for Anabaena are much larger than for Chlorella. The model provides a conceptual basis for understanding the relationship between rates of photosynthesis and intracellular nutrients in populations of planktonic algae.
Respiration and the effects of pressure on the mesopelagic vertically migrating squid Histioteuthis heteropsis1
Authors: Belman Bruce W.
Published: March 2010

The effects of hydrostatic pressure and dissolved oxygen concentration on oxygen consumption rates were examined in the mesopelagic, vertically migrating squid Histioteuthis heteropsis from southern California offshore waters. Elevated hydrostatic pressures (to 136 atm) had no significant effects on oxygen consumption rates at 5°C. Low oxygen concentrations (<0.5 ml O2 · liter−1) depressed rates of oxygen consumption. These findings suggest that metabolism is pressure insensitive during vertical migrations and that at least partial anaerobiosis may be necessary to supply the total energy needs of this species at daytime depths in the oxygen minimum layer off southern California.
Specific blue‐green algal carotenoids in sediments of Esthwaite Water
Authors: Griffiths Mary
Published: March 2010

Two cores from Esthwaite Water have been analyzed for oscillaxanthin, derived from Oscillatoria alone, and myxoxanthophyll found only in blue‐green algae. Myxoxanthophyll profiles are similar for the two cores with maxima at 6–7 cm and 14–16 cm and low values in the top 5 cm and below 17–19 cm. Oscillaxanthin follows the same general pattern but without pronounced maxima. Such profiles can be used to indicate the appearance of Oscillatoria and other blue‐green algae in a lake, and indirectly, the onset of eutrophication.

Raw data for the blue‐green algae present in the lake between 1948 and 1976 have been analyzed. When the years of maximal algal counts in the lake are correlated with the depths of myxoxanthophyll maxima in the sediment, an annual sedimentation rate for the top 15 cm of 0.6 cm · yr−1 is obtained, which agrees quite well with results by other methods.
Relationships among substrate, flow, and benthic microalgal pigment density in the Mechums River, Virginia 1
Authors: Tett Paul , Gallegos Charles , Kelly Mahlon G. , Hornberger George M. , Cosby B. J.
Published: March 2010

Measurements of photosynthetic pigments have been used to estimate the biomass of benthic microalgae on soft and hard substrates in a small river in the Virginia Piedmont. The irregular distribution of periphyton was partially related to substrate distribution and is explained as a result of spatial variations in the current regime in the river. High flow due to unpredictable and heavy rainfall is shown to be the main factor controlling algal biomass. Deterministic predictions of algal crop are therefore not possible in rivers of this type.
Nutrient and particulate fluxes in a salt marsh ecosystem: Tidal exchanges and inputs by precipitation and groundwater 1
Authors: Valiela Ivan , Teal John M. , Volkmann Suzanne , Shafer Deborah , Carpenter Edward J.
Published: March 2010

Waterborne nutrients enter Great Sippewissett Marsh through groundwater, rain, and tidal flooding. The ebb of tidal water removes nutrients. During summer, uptake by marsh biota leads to net import of nutrients. The increased export of ammonium in August may be due to leaching from senescent marsh plants. There is a net annual export of ammonium, nitrate, nitrite, dissolved organic (DON) and particulate (PN) nitrogen, particulate carbon (PC), and phosphate. Ammonium, DON, and PN are the major forms of nitrogen exported. Nutrient concentrations in coastal and marsh water are correlated, and marsh exports could contribute substantially to nutrient supplies of coastal waters.

Groundwater entering the marsh provides primarily NO3‐N and DON. Nutrient inputs through precipitation consist primarily of DON, NO3‐N, and NH4‐N. Particulate materials in rain have a high C:N ratio, contributing little to enrichment of the nitrogen‐limited salt marsh. Groundwater carries over 20 times the amount of nutrients brought in by rain. The nitrogen provided by both sources is more than enough to support annual plant growth. Inputs of nitrogen by groundwater arc therefore important to the nitrogen economy of a salt marsh.

About half the dissolved inorganic nitrogen brought into the marsh by groundwater is converted to and exported as PN. The marsh thus transforms the nitrogen that would have been used by primary producers into a form suitable for consumers such as shellfish. Large amounts of apparently refractory DON enter the marsh in groundwater and similar amounts are exported by tides. PC exported to coastal water is equivalent to 40% of the net annual production of Spartina alterniflora, the dominant marsh plant.
Bathymetry as an indicator of net circulation in well mixed estuaries 1
Authors: Kjerfve Björn
Published: March 2010

In well mixed, high salinity estuaries of the southeastern U.S. the net circulation is mirrored in the bathymetry. Measurements in North Inlet, South Carolina, indicate a net current reversal across the estuary. The cross section bathymetry is usually bimodal with two channels separated by a shallow area. The deeper channel experiences ebb‐directed net flow with ebb‐oriented sand waves as the predominant bedform. In the shallower channel, the net current is flood directed. In well mixed estuaries similar to North Inlet, it may be possible to determine qualitative circulation features from a few lateral and longitudinal bathymetric traces without measurements of current velocity and salinity.
Release of dissolved organic carbon by grazing zooplankton
Authors: Lampert Winfried
Published: March 2010

The release of dissolved organic. carbon (DOC) by Daphnia pulex de Geer from six different algal species was evaluated using 14C‐labeled algae and analyzing the labeled dissolved organic matter. Up to 17% of the algal carbon ingested was initially lost as DOC from algae damaged during feeding. Only about 4% of the carbon from algae swallowed whole is released during ingestion. Additional DOC is produced by secretion from Daphnia and by leaching from their feces. More than 10% of the algal particulate organic carbon removed from suspension by grazing was transformed to DOC in the case of all food species except the very small green alga Stichococcus.
Microbial organic carbon recovery in aquatic ecosystems1
Authors: Paerl Hans W.
Published: March 2010

Aquatic heterotrophic microorganisms were examined as producers of particulate matter in addition to their tradionally defined roles as mineralizers. Dialysis experiments illustrated the significance of microbial scavenging of dissolved organic carbon (DOC) in particulate organic carbon (POC) formation. Since microbial respiration of single assimilated DOC compounds can range between 10 and 60%, a majority of nonrespired substrates may at times go into synthesis of structural carbon, much in a size range available to grazers. Dialysis bag experiments demonstrated the relationships between ambient DOC supplies and POC formation. Autoradiographs and scanning electron micrographs showed some natural planktonic assemblages responsible for conversion of DOC to POC, leading to the formation of particulate matter.
Alkalinity changes and coral reef calcification1
Authors: Kinsey Donald W.
Published: March 2010

In estimates of coral reef calcification based on alkalinity anomalies, interference from changes in the concentration of ions such as nitrate, ammonium, and sulfate typically is likely to cause errors of <5%. In the particular case of the open lagoon, the error from sulfate reduction could be as high as 15%.
Recent changes in the meromictic status of Big Soda Lake, Nevada1
Authors: Kimmel Bruce L. , Gersberg Richard M. , Paulson Larry J. , Axler Richard P. , Goldman Charles R.
Published: March 2010

Big Soda Lake has shifted from a partially closed to an open meromictic system, probably due to a progressive depression of the chemocline to a level below that of subsurface inflow. The stability increase initially accompanying that shift has been followed by a gradual decrease in stability. The observed mean annual work done and chemocline descent rate indicate that meromixis in Big Soda Lake is unlikely to persist for longer than another few decades.
The role of ice and snow in lake heat budgets
Authors: Adams W. P. , Lasenby D. C.
Published: March 2010

Methods of precisely calculating the latent heat terms for snow and ice in the winter energy budget of lakes are presented. The ice term is normally overestimated and the snow term underestimated by existing methods.
A new method for collecting water from beneath the ice1
Authors: Patterson R. J. , Dijkes L. , Frape S. , McLeod R. A. , Wickens J.
Published: March 2010

A subice sampler is made of a length of tubing which can be tightly sealed at one end by means of a clamp. It is placed open end down through a hole in the ice, pressurized and sealed to maintain the water level below the ice base so that water inside will not freeze, and allowed to freeze in place. Water samples from beneath the ice are collected by releasing the pressure in the tube and withdrawing water with a small hand‐operated pump.
Seasonal vitamin B12 and phytoplankton distribution near Napeague Bay, New York (Block Island Sound)1
Authors: Bruno Stephen F. , Staker Robert D.
Published: March 2010

Vitamin B12 levels in seawater were assayed over a 13‐month period with Thalassiosira pseudonana Hasle et Heimdal, clone 3H. Concentrations at four different stations ranged from undetectable to 10.6 ng·liter−1. Concentrations during November– December 1975 were undetectable and may have limited the growth of B12 auxotrophic phytoplankters. A positive significant correlation, on a seasonal cycle, was found between B12 levels and dinoflagellate cell numbers and negative significant correlations between B12 and chlorophyll a concentrations at the same two stations. B12 levels were highest during summer when other nutrients (NO3−‐N, PO43−‐P) were low. Bacterial production is suggested as a source of the summer concentrations.
Generation times of 3 h for Sargasso Sea microplankton determined by ATP analys
Authors: Sheldon R. W. , Sutcliffe W. H.
Published: March 2010

Microplankton growth rates were determined from biomass (ATP) increase of incubated samples from near‐surface waters at two locations in the Sargasso Sea. Measured growth rates were quite variable but the results tended to cluster around a generation time of 3 h. Estimates of primary production derived from these growth rates are roughly an order of magnitude greater than those derived from measurements of 14C uptake.
Extraction of ATP from Aufwuchs communities1
Authors: Clark James R. , Messenger David I. , Dickson Kenneth L. , Cairns John
Published: March 2010

Acetone extracts prepared by an acid‐ether elution procedure for ATP analysis by the firefly luminescence reaction yielded estimates comparable to those of the boiling tris buffer method and an acetone distillation technique, from algal and fungal cultures and colonized glass slides. The acetone acid‐ether technique was more effective than the other methods in extracting ATP from Aufwuchs attached to rock substrates. The technique allows estimates of ATP and chlorophyll to be made from a single sample.
Solar middle ultraviolet (UV‐B) measurement coastal waters rich in yellow substance
Authors: Højerslev Niels K.
Published: March 2010

The properties of a Danish UV‐B meter and a Robertson UV‐B meter, designed for underwater use, are discussed. Measurements of the radiant energy in the UV‐B region in waters rich in yellow substance are appropriately performed by means of the Danish UV‐B meter only.
Carnivorous feeding by a small marine copepod 1
Authors: Lampitt Richard S.
Published: March 2010

Adults of Oithona nana feed on copepod nauplii of 110‐µm body length. An Ivlev curve is used to describe feeding as a function of prey density. At natural prey densities, carnivorous feeding would provide only 25% of its metabolic requirements. Very low respiration rate and the nature of the diet are important considerations in assessing the ecological effect of this abundant species.
Some size‐dependent inhibitions of larger cladoceran filterers in filamentous suspensions
Authors: Webster Katherine Emerson , Peters Robert Henry
Published: March 2010

Laboratory experiments with Daphnia pulex, Simocephalus vetulus, Daphnia ambigua, Ceriodaphnia quadrangula, and Bosmina longirostris showed that large algal filaments have a differential effect on zooplankton of different size. As filament concentration increased, larger animals filtered at low rates, increased their rejection rates, and decreased their brood sizes. In nature, this greater sensitivity of larger animals could contribute to an increase in the proportion of smaller animals during blooms of filamentous algae.
Ingestion of the blue‐green alga Trichodesmium by the harpactacoid copepod, Macrosetella gracilis
Authors: Roman Michael R.
Published: March 2010

The marine planktonic copepod, Macrosetella gracilis, ingested from 90 to 126% of its body carbon per day when feeding on the blue‐green alga Trichodesmium. Comparisons of laboratory ingestion rates with field measurements of M. gracilis abundance and the autotrophic activity of Trichodesmium indicate that M. gracilis could convert much of the carbon and nitrogen fixed by Trichodesmium into secondary production.
Quantitative description of steady state, nutrient‐saturated algal growth, including adaptation
Authors: Bannister T. T.
Published: March 2010

Steady state, nutrient‐saturated phytoplankton growth can be quantitatively described by four equations: an empirical equation relating growth rate µ8 to absorbed irradiance ξ; a different equation relating µ8 and ξ derived from the empirical equation relating instantaneous rate of gross photosynthesis to irradiance; an empirical equation relating the respiratory rate constant Rp to growth rate; and an equation stating the approximate constancy of the ratio ξp/θ of the light saturation parameter ξp of the photosynthetic light curve and the C:Chl a quotient θ. The equations involve eight constant parameters which were evaluated for Chlorella pyrenoidosa from data in the literature. The four equations do not incorporate an empirical description of the adaptive parameter functions ξp(µ8) or θ(µ8). However, the equations can be solved simultaneously to obtain these functions. The derived functions agree with the experimental ones for C. pyrenoidosa. Since the equations not only describe respiration and the light curves of growth and photosynthesis, but also predict ξp and θ, they constitute an improved model of nutrient‐saturated algal growth: given any irradiance, the equations predict µ8, Rp, ξp, and θ and the specific light curve of photosynthesis. The model provides a necessary foundation for subsequent description of nutrient‐limited growth in culture and in nature.
Protonation equilibria of marine dissolved organic matter1
Authors: Huizenga Douglas L. , Kester Dana R.
Published: March 2010

Dissolved organic matter isolated by activated charcoal adsorption from river, estuarine, coastal, and open ocean waters was examined by acid‐base titration in 0.7 molal NaClO4 medium. Two types of sites were present in the pH range 2–8. One set of sites with an inflection point at pH 3.5 amounted to 11 µmol of sites per milligram of organic carbon. These sites were present in all samples and showed uniform properties among the samples from different marine environments. A second set of sites with an inflection point at pH 6.5 was present in some samples and amounted to <1 µmol of sites per milligram of organic carbon. These results provide a characterization of the acid‐base equilibria of marine organic matter which is required in an assessment of possible trace metal‐organic interactions in seawater.
Seiches, tides, and wind set‐up on Lake Kariba
Authors: Peter R. B. Ward
Published: March 2010

Water level records from six near shore towers at Lake Kariba provide information on surface seiches, tides, and wind setup.
Applying phosphorus loading models to embayments1
Authors: Chapra Steven C.
Published: March 2010

An explicit turbulent mass transport term is added to a phosphorus budget model to make it applicable to completely mixed water bodies with open boundaries; an application to Saginaw Bay demonstrates the importance of this modification. A method is devised to incorporate turbulent diffusion into loading plots by adjusting the loading term to include the flux of phosphorus from the main lake into the bay and including the effect of turbulent flow in the residence time.
The density and speed of sound of Orca basin waters1
Authors: Millero Frank J. , Lo Surdo Antonio , Chetirkin Peter , Guinasso Norman L.
Published: March 2010

The composition of samples of waters collected in the Orca depression (Gulf of Mexico) above and below the seawater‐brine interface was characterized by measuring chlorinity (Cl) and salinity (S). The ratio of S:Cl = 1.6823 in the brines, compared with 1.6817 calculated from composition data. Densities and sound speeds of the waters were measured at 15°, 25°, and 35°C and the results fit to chlorinity functions. The standard deviations in density are ≈60 × 10−6 g·cm−3, in sound speed ≈1.2 m·s−1. These standard errors are about 6 times larger than the precision of the measurements and are due to errors in determining Cl and to changes in the brine composition across the interface.

Conductivity, density, and sound speed were measured in weight‐diluted brine samples and the results used to calculate the relationship of evaporation salinity (Sevap) to salinity calculated from measurements on standard seawater. The differences in Sevap and S determined from properties of standard seawater are caused by hydration changes in the major constituents.

The measured brine densities were compared with values calculated by using an additivity method and the known composition of the waters and agree to within ±280 × 10−8 g·cm−3 over the temperature range measured.
Nutrient‐determined dominance in multispecies chemostat cultures of diatoms1
Authors: Mickelson Michael J. , Maske Helmut , Dugdale Richard C.
Published: March 2010

Thalassiosira gravida was rapidly displaced from ammonium‐limited chemostats at moderate (D = 0.03·h−1) and low (D = 0.01·h−1) dilution rates by Skeletonema costatum or Chaetoceros septentrionalis. Reduced temperature or reduced light did not favor Thalassiosira. Chaetoceros displaced Skeletonema at D = 0.03·h−1 but the two species coexisted at D 0.01·h−1. A brief temperature increase triggered changes in population densities in chemostats with coexisting species, leading to an increase in the less abundant species. Reduced turbulence did not change the pattern of coexistence.

Nutrient‐dependent growth‐rate kinetics for the three species were deduced from rates of displacement in competition experiments and from published uptake kinetic and chemical composition data. The kinetics deduced by the two methods were qualitatively similar. Nutrient kinetics apparently do not explain the survival of natural populations of T. gravida in the field. On the basis of these results, a nutrient‐based functional group of phytoplankton is defined to include S. costatum and C. septentrionalis and exclude T. gravida.
The effect of organic nitrogen supplement on the utilization of different sources of detritus1
Authors: Tenore Kenneth R. , Hanson Roger B. , Dornseif Bruce E. , Wiederhold Craig N.
Published: March 2010

A particulate organic nitrogen supplement was added to two detrital materials (red macroalga Gracilaria foliifera and marsh grass Spartina alterniflora) and its effect on their utilization by the polychaete Capitella capitata was investigated with isotope tracer techniques.

With the decay‐resistant Spartina, added nitrogen had no effect on the oxidation or the net incorporation of Spartina carbon by the worms. With easily decomposable Gracilaria detritus there was an exponential increase in both oxidation and net incorporation with increasing nitrogen. Added organic nitrogen had no effect on the microbial biomass associated with Spartina detritus but resulted in an increase with Gracilaria detritus.

Nitrogen enrichment by microbial activity is not the only regulator of nutritional value of detritus to macroconsumers. The extent to which the substrate can be broken down and utilized by associated microbes and macrodetritivores also influences the nutritional quality of detritus to macroconsumers.
Thiosulfate, polythionates, and rhodanese activity in Lakes Erie and Ontario sediments
Authors: Nriagu J. O. , Coker R. D. , Kemp A. L. W.
Published: March 2010

The concentrations of thiosulfate (10–20 µg·g dry wt−1) and polythionates (10– 70 µg·g−1) in Lake Ontario sediments are much higher than those (0–20 and 5–40 µg·g−1) in the more reduced Lake Erie sediments. The distribution of these labile compounds is considered in relation to the forms of sulfur and sulfur bacteria in the different basins of Lake Erie and the importance of microenvironments in the formation of thiosulfate and polythionates is emphasized. The high concentrations in Lake Ontario suggest that once formed, the thiosulfate can persist for a long time in sediments with limited amounts of oxygen. The correlation between rhodanese activity and thiosulfate plus polythionates suggests that rhodanese may catalyze some of the processes responsible for the generation and extinction of these sulfur compounds in lake sediments.
Settling behavior of natural aquatic particulates1
Authors: Chase Robert R. P.
Published: March 2010

The validity of Stokes Law as an approximation to the drag force on sediments (organic‐mineral aggregates) from lacustrine and marine environments was examined under controlled laboratory conditions. The settling characteristics of aggregates in the size range of 5–500 µm were inconsistent with a Stokesian assumption. Experiments with distilled, organics‐free, and natural waters indicated that aggregate behavior is altered by the presence of naturally occurring surface coatings, solution electrolytes, and dissolved organic substances.

Although rotational effects appear unimportant, the above factors combine to produce a reduction in overall nonlinear skin friction which is manifested by up to an order of magnitude increase in velocity over the predicted value for an aggregate of mean dimension (∼28.5 µm).
Arsenic speciation in seawater and interstitial waters: The influence of biological‐chemical interactions on the chemistry of a trace element1
Authors: Andreae Meinrat O.
Published: March 2010

Four species of arsenic were found in samples of seawater and interstitial water from the northeast Pacific and the continental borderland off southern California: arsenate, arsenite, methylarsonate and dimethylarsinate. All were present in the photic zone, with a good correlation between photosynthetic activity and the concentration of the methylated arsenicals. There is less arsenite in the surface waters than in the deep waters, suggesting biological uptake and transport. A sharp increase of arsenate at the base of the photic zone indicates rapid regeneration of this species. In the deep waters arsenate is dominant, but arsenite is still present in excess of equilibrium concentrations. No arsenic biomethylation was found in the interstitial waters of oxic and anoxic sediments, but arsenite was present there. In Santa Barbara Basin arsenite accounts for 20% of the arsenic in the interstitial water, the highest proportion found. Total arsenic is lower in the interstitial than in the overlying waters, suggesting removal of arsenic into the solid phases by adsorption or coprecipitation. Biological‐chemical interactions and the kinetics of redox reactions are important in influencing the speciation of arsenic.
Effects of nutrients and temperature on decomposition of Myriophyllum spicatum L. in a hard‐water eutrophic lake1
Authors: Carpenter Stephen R. , Adams Michael S.
Published: March 2010

Temperature, phosphorus, and nitrogen were investigated as possible factors influencing decay of Myriophyllum spicatum shoots. In laboratory experiments, nitrogen enrichment significantly increased decay rates while phosphorus enrichment did not. Similar increases in decay rate per unit of added nitrogen occurred whether nitrogen was provided as nitrate or was present as additional tissue nitrogen. Exponential decay coefficients depended on temperature with a Q10 of about 3.

Predictions of decay rates during litter bag experiments were based on laboratory responses of decay rate to temperature and initial nitrogen concentration of the shoots. Observed decay rates correlated closely with predictions, demonstrating the usefulness of temperature and shoot nitrogen content in explaining variations in decay rates in Lake Wingra. However, predictions underestimated decay rates. Possible explanations for the discrepancies include slow establishment of the detrital microflora, lower nitrogen availability, and absence of animals in the laboratory incubations.
Organic detritus particles: Initiation of motion criteria
Authors: Fisher John S. , Pickral James , Odum William E.
Published: March 2010

The criteria for the initiation ofmotion for organic detrital sediments appear to follow the same Shields relationship as sand and other uniform inorganic sediments. The salt marsh tidal creek samples tested include mud particles and stem, leaf, and root fragments of marsh grasses. The measurement of particle diameter is replaced with an equivalent diameter determined from fall velocity and density.
The toxic effect of copper on Oscillatoria (Trichodesmium) theibautii1
Authors: Rueter John G. , McCarthy James J. , Carpenter Edward J.
Published: March 2010

[14C]CO2 fixation in Oscillatoria theibautii decreased in response to copper at low cupric ion activities (10−10 M) in test media containing Tris as a copper chelator and to low concentrations (10−8 M) of total added copper in filtered seawater. This sensitivity could be important to natural systems as well as laboratory and shipboard cultures.
Importance of lake‐river interaction on seasonal patterns in the general circulation of Kamloops Lake, British Columbia
Authors: Carmack Eddy C. , Gray Colin B. J. , Pharo Christopher H. , Daley Ralph J.
Published: March 2010

The physical effects of a large river (Thompson River) entering a deep, intermontane lake (Kamloops Lake, British Columbia) suggest that, depending upon its temperature relative to that of lake water, river water moves through the lake as a surface overflow, an intermediate depth interflow, or a near‐bottom underflow. Circulation is further influenced by the earth’s rotation so that the incoming river flows preferentially along the right‐hand shoreline of the lake. Convective overturn in autumn and spring is influenced by cabbeling, which occurs whenever two parcels of water, one warmer than 4°C and one colder, combine to form a mixture whose temperature is at or near 4°C.
Estimates of vertical eddy diffusion through the thermocline from phytoplankton nitrate uptake rates in the mixed layer of the eastern tropical Pacific1
Authors: King Frederick D. , Devol Allan H.
Published: March 2010

Vertical eddy diffusion coefficients ranging from 0.05–1.1 cm2·s−1 were calculated from phytoplankton nitrate uptake rates in the mixed layer and nitrate gradients at the top of the thermocline of the eastern tropical North Pacific. An empirical relationship was determined between these diffusion coefficients and density gradients in the thermocline. This relationship was used to calculate nitrate fluxes through the thermocline at several stations where nitrate uptake was not measured, and the fluxes indicated that an average of 29% of the primary productivity was supported by the uptake of nitrate‐nitrogen.
Reflectance spectroscopy of marine phytoplankton. Part 1. Optical properties as related to age and growth rate1
Authors: Kiefer D. A. , Olson R. J. , Wilson W. H.
Published: March 2010

The optical properties of two species of marine phytoplankton were characterized by application of principles of reflectance spectroscopy. Suspensions of Thalassiosira pseudonana from batch cultures and Monochrysis lutheri from continuous cultures were placed in a spectrophotometer for measurements of diffuse spectral transmittance and reflectance. These measurements yielded values for the diffuse absorption coefficiant, a*(λ), and diffuse backscattering coefficient, b*(λ), two parameters that can be applied to calculations of the effect of phytoplankton crop size on ocean color spectra.

Results show that the absorption and scattering properties of a cell suspension contain information related not only to cell concentration but also to cell age or growth rate. Most important, in batch culture the ratio a*(λ):b*(λ) decreases with age once the plateau phase has been reached, and in continuous culture the ratio of absorption to backscattering coefficients is roughly proportional to the specific growth rate of the cells. Such changes in a*(λ): b*(λ) are larger at the red absorption maximum of chlorophyll a than in the blue, where accessory pigments also contribute to the absorption coefficient.