bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace metal‐chelator interactions and phytoplankton growth in seawater media: Theoretical analysis and comparison with reported observations 1
Authors: Jackson George A. , Morgan James J.
Published: March 2010

Effects of trace metal chelators in seawater are examined theoretically in terms of equilibrium chemical speciation in seawater; of chemical interactions between all metals, naturally occurring ligands, and added organic chelating agents of various binding strengths and total concentrations; and of transfer of trace metals to the phytoplankton cell surface. An equilibrium model involving 18 metals and 8 ligands is applied to find the metal species in natural seawater, chelator‐amended seawater, and synthetic seawater media. Three mechanisms for enhanced supply of iron via chelation arc examined: transport through the membrane, ligand exchange at the cell surface, and increased supply of iron to the cell surface by dissociation of a chelate. None account for the observed effects of chelator variations on growth rate. Detoxification of toxic metals via chelation shows a strong correlation between growth rate and free Cu2+ computed at equilibrium in solution.
Copper sensitivity of Gonyaulax tamarensis1
Authors: Anderson D. M. , Morel F. M. M.
Published: March 2010

The copper sensitivity of the dinoflagellate Gonyaulax tamarensis was examined in artificial seawater medium. Two short term responses of the organism to copper toxicity are rapid loss of motility and reduced photosynthetic carbon fixation. The chelators tris(hydroxymethylamino)methane (Tris) and ethylenedinitrilotetraacetic acid (EDTA) were used to demonstrate that copper toxicity is a unique function of cupric ion activity. Copper additions to medium containing EDTA equilibrated with the chelator relatively slowly, resulting in misleading short term data. This kinetic effect was not seen when the major copper chelator was Tris or when the copper was added in a chelated form with EDTA. Variations in manganese concentrations over two orders of magnitude did not alter the results.

Cells of G. tamarensis are 100% nonmotile at a calculated cupric ion activity of 10−9.7 M with 50% of the cells nonmotile at 10−10.4 M. Nonmotile cells do not divide or grow larger. Gonyaulax tamarensis growth is totally inhibited at cupric ion activities that only partially inhibit the growth of four other species that have been studied extensively. Furthermore, this toxicity occurs at the calculated copper activity of natural waters, assuming only inorganic copper complexation. Thus organic chelation may be necessary before G. tamarensis can successfully compete with other algal species in coastal waters.
Diel variation in feeding behavior of Daphnia pulex. Influences of food density and nutritional history on mandibular activity 1
Authors: Starkweather Peter L.
Published: March 2010

Individuals of the planktonic cladoceran Daphnia pulex express well defined daily patterns in mandibular activity. The 24‐h cycles are characterized by high, uniform daytime rates and distinct nocturnal minima. Daytime rates are strongly dependent on animal size and ambient food concentration, the highest values being obtained with small animals feeding on dense cell suspensions. Starved D. pulex express diel patterns which differ from cycles of prefed animals, and those of prefed groups vary with food cell density. Typical 24‐h patterns of mandibular beat can be substantially altered by increases in food availability, especially when the changes occur shortly before light–dark transitions. The results implicate nutrition and feeding history as primary influences in the expression of feeding‐related periodicities in cladoceran zooplankton.
Nitrogen fixation by algae in a Massachusetts salt marsh 1
Authors: Carpenter Edward J. , Van Raalte Charlene D. , Valiela Ivan
Published: March 2010

Over a 3‐year period, N2 fixation on the surface of a Cape Cod salt marsh was highest in summer, with overall rates of about 10–20 mg N m−2 d−1. This average, coupled with N2 fixation in the rhizosphere (ca. 80 mg N m−2 d−1), compared favorably with the highest N2 fixation rates measured anywhere. There were significant variations from one marsh habitat to another; the blue‐green algal mat had the highest rate of N2 fixation per unit area (100–200 ng N cm−2 h−1), but due to its large area, the low marsh with short Spartina contributed the greatest amount of fixed N. Nitrogen is fixed on the marsh surface primarily by blue‐green algae.
Methane cycling in a eutrophic shield lake and its effects on whole lake metabolism 1
Authors: Rudd John W. M. , Hamilton R. D.
Published: March 2010

The methane cycle of an artificially eutrophic shield lake is considered by relating in situ rates of production to rates of oxidation and evasion. Methane production rates f’or oxygenated and anoxic sediments were quite consistant throughout the year, ranging from ~1.0 to ~10 mmol m−2 sediment d−1. Methane oxidation rates were highly variable (0.02–32 mmol m−2 lake surface d−1) as were evasion rates (0.0–60 mmol m−2 lake surface d−1). Oxidation and evasion rates both peaked during fall overturn and were very low during the remainder of the year. Methane production was important in regenerating carbon from sediments. Fifty‐five percent of total carbon input was regenerated as methane during 1 year and 36% of this total carbon input was recycled by methane oxidation. Methane oxidation was not an important source of carbon dioxide for primary producers or of seston for secondary grazers during the summer. During some winters production of particulate carbon by methane oxidizers may have been an important source of seston for grazers. Methane oxidation was the most important contributor to the development of total lake anoxia under ice cover.
Methane oxidation in Cape Lookout Bight, North Carolina 1
Authors: Sansone Francis J. , Martens Christopher S.
Published: March 2010

Aerobic methane oxidation rates in seawater from Cape Lookout Bight, determined in the laboratory by concentration changes during incubation at 25° ± 0.5°C, averaged 0.010 ± 0.008 µM d−1 when oxygen was high (>90 µM) and dissolved inorganic nitrogen concentrations were below 14 µM, typical of chemical conditions in the bight water column. When DIN concentrations exceeded 15–16 µM with oxygen the same, the methane oxidation rate averaged 0.210 ± 0.026 µM d−1, suggesting that the methane‐oxidizing bacteria isolated from bight waters were facultative microaerophiles like those found in freshwaters. The results of an in situ incubation experiment agreed with those of the laboratory studies.
Conifer needle processing in a subalpine lake 1
Authors: Rau Greg H.
Published: March 2010

Fir and hemlock needles lost an average of 80–90% of their initial dry weight after a 1‐year incubation on a littoral benthic site in Findley Lake, Washington. Considerably less mean weight was lost from needles in fine and coarse mesh bags. In all treatments there was little change in mean needle weight during the second year of the experiment.
On predicting phytoplankton growth rates from carbon:nitrogen ratios 1
Authors: Donaghay Percy L. , DeManche J. Michael , Small Lawrence F.
Published: March 2010

Some workers have suggested that phytoplankton C:N (or N:C) ratios might be usefiil in estimating specific growth rates (µ) under nitrogen‐limited field conditions. Howevcr, C:N is a function of µ:µmax rather than µ alone, so that some determination of µmax is required in addition to a C:N measurement before µ can be estimated. Moreover, the relationship between C:N and µ:µmax is not very precise.
Loss of 14C activity after chemical fixation of phytoplankton: Error source for autoradiography and other productivity measurements 1
Authors: Silver Mary Wilcox , Davoll Peter J.
Published: March 2010

Loss of fixed, filter‐retainable 14C due to treatment with preservatives is reported in productivity studies of natural phytoplankton populations. Treatment with formaldehyde consistently results in large decreases in activity, whereas iodine and gluteraldehyde treatments cause losses with some populations but not with others. The extent of loss with all treatments varies over time in natural populations, suggesting that no simple correction factor can be applied for all populations and that leakage may not be uniform for different species. Should activity losses vary by species, then quantitative autoadiographic methods for estimating individual species production rates may require individual correction factors for each species when preservative‐caused losses occur.
A modified chamber for use with an oxygen electrode to allow measurement of incident illumination within the reaction suspension
Authors: Griffiths Dilwyn J. , Thinh Luong‐Van , Florian Zoltan
Published: March 2010

A method for precise measurement of incident illumination at the center of an algal suspension within the reaction chamber of an oxygen electrode allows reliable comparisons to be made of the photosynthetic characteristics of cultures of differing population densities and provides estimations of the degree of shade adaptation in cells of Chlorella comparable with those obtained by other methods. The reliability of the method is further confirmed by comparing the photosynthetic characteristics of synchronous cultures of Chlorella at different stages in the life cycle.
Thermal microstructure on a lake slope 1
Authors: Caldwell Douglas R. , Brubaker John M. , Neal Victor T.
Published: March 2010

As shallow water is approached via a steep lake‐bottom slope, increased mixing of heat is indicated by the presence of a highly “stepped” temperature profile. This mixing activity operates over a wide range of vertical scales.
Spatial dispersion of benthic Foraminifera in the abyssal central North Pacific 1
Authors: Bernstein Brock B. , Hessler Robert R. , Smith Robert , Jumars Peter A.
Published: March 2010

Five 0.25‐m2 box cores (four open cores and one vegematic core subdivided in situ into 25 contiguous 10‐ × 10‐cm subcores) reveal that populations of benthic agglutinated Foraminifera in the central North Pacific are extremely abundant and diverse. As many as 120 species and 10,310 total fragments occur in a single open core, and the Foraminifera outnumber all metazoan taxa combined by at least an order of magnitude. Significant patchiness occurs on both the between‐core scale of kilometers and the within‐core scale of centimeters. Few species occurred in all cores and those that did were not abundant. Hierarchical classification and multiple discriminant analysis on the resultant subcore groups in the vegematic core suggest potential interactions between certain species of Foraminifera and such external variables as surface deposit feeders, subsurface deposit feeders, carnivores, filter feeders, biogenic surface structure, and manganese nodules. Multiple regressions of foraminiferan species against all the external variables substantiate the existence of patterns of association. Foraminifera are important components of the benthic fauna, acting, among other things, as predators and disturbance agents. It may well be that they have a more significant effect on the structure and dynamics of deep‐sea henthic communities than have any of the metazoan macrofaunal taxa that are the usual objects of deep‐sea studies.
Spatial and temporal heterogeneity in a sand bottom epifaunal community of invertebrates in shallow water 1
Authors: Davis Noël , VanBlaricom Glenn R.
Published: March 2010

Temporal and spatial patterns of abundance in a community of epifaunal invertebrates on the shallow subtidal sand plain at La Jolla, California, were studied from March 1974 through September 1975. In similar work by Fager in the same location from 1957 to 1963, densities of the principal species were remarkably nonvariant, both in time and space. The more recent work showed both long and short term fluctuations in the abundances of many of these species as well as physical and biological spatial heterogeneity. These differences from Fager’s results as well as evidence of temporal fluctuations in populations of abundant species on portions of the sand habitat adjoining the primary study areas suggest that the shallow sand community lacks long term numerical stability.
Polymorphism and predation: The effect of invertebrate predation on the distribution of two varieties of Daphnia carinata in South India ponds 1
Authors: O'Brien W. John , Vinyard Gary L.
Published: March 2010

Two varieties of Daphnia carinata showed a disjunct distribution in four ponds in South India: an exuberant variety, cephalata, was generally restricted to those ponds that did not contain a more usual morph, forma typica, and vice versa. The ponds studied were quite similar except for the presence of large Anisops spp. in the two ponds containing cephalata and their absence or low abundance in those containing forma typica. Experiments showed that the exuberant cephalata form was frequently able to evade capture and thus was preyed upon at a much lower rate than forma typica. In the absence of such predation, however, forma typica had the competitive advantage: its survivorship and rate of increase were higher and its feeding rate more rapid. Thus the exuberant morphology of D. carinata var. cephalata appears to be an adaptation that reduces invertebrate predation.
Factors regulating phytoplankton production and standing crop in the world's freshwaters
Authors: Schindler D. W.
Published: March 2010

A regression analysis of global data for freshwater phytoplankton production, chlorophyll, and various nutrient parameters revealed the following: A high proportion of the variance in both annual phytoplankton production and mean annual chlorophyll could be explained by annual phosphorus input (loading), once a simple correction for water renewal time was applied. Good relationships were also found between phosphorus loading and mean total phosphorus concentration, and between total phosphorus concentration and chlorophyll. The slope of the regression of total phosphorus on phosphorus loading for stratified lakes was not significantly different from that for unstratified lakes, suggesting that the effect of stratification on phosphorus concentration is insignificant compared to external sources of the element. Nutrient input, which was unavailable in previous analyses, appears to be an important factor in controlling freshwater production. There is some evidence for a correlation between latitude and nutrient input, and it is possible that this may explain the good correlation between latitude and production observed by earlier investigators.
An equilibrium model describing the influence of humic materials on the speciation of Cu2+, Zn2+, and Mn2+ in freshwaters
Authors: Wilson Donald E.
Published: March 2010

A model for the speciation of Cu2+, Mn2+, and Zn2+ ions in freshwaters was constructed. The solubilities of CuO, MnCO3, and Zn2SiO4 are assumed to control the free metal ion concentrations. Model variables are pH, alkalinity, concentrations of competing cations, chemical characteristics and concentrations of humic substances, and inorganic ligand concentrations. The inorganic anions considered are Cl−, SO42−, OH−, HPO42−, HCO3−, and CO32−.

Calculations indicate that all three metals exist primarily as bicarbonate and carbonate ion pairs in waters of 10−2 eq·liter−1 alkalinity. Except for Cu, the uncomplexed ions are predominantly low‐alkalinity species (10−4 eq· liter−1). Humic complexes did not form in appreciable amounts in waters having small quantities of organic material. At high organic concentrations (15 mg·liter−1) the amount of metal ion bound by humic substances is substantial and could control micronutrient availability in freshwaters.
Silicic acid incorporation in marine diatoms on light:dark cycles: Use as an assay for phased cell division 1
Authors: Chisholm S. W. , Azam F. , Eppley R. W.
Published: March 2010

The timing of silicon incorporation in diatom populations grown on light:dark cycles was monitored using [68Ge]Ge(OH)4 as a tracer for Si(OH)4. The time‐course of frustule formation closely followed the time‐course of cell division in all species examined, and the timing of these processes relative to the light:dark cycle was different for each species. Total uptake of Si(OH)4 was found to be higher than Si(OH)4 incorporation in some species.

Seawater samples from the Gulf of California and the Southern California Bight also showed periodicity in Si(OH)4 incorporation when incubated outside under ambient light and surface temperature. The degree of periodicity seems to be inversely correlated with diatom species diversity in the samples, which is consistent with the hypothesis that the pulses in Si(OH)4 incorporation reflect phased cell division in individual species of diatoms.
Seasonal changes in the species composition of luminous bacteria in nearshore seawater
Authors: Ruby E. G. , Nealson K. H.
Published: March 2010

Three species of luminous bacteria are found in the nearshore surface waters of southern California; two of these account for over 99% of the strains isolated. Photobacterium fischeri is found throughout the year in concentrations between 1 and 5 cells Beneckea harveyi predominates in summer (2.5–3.0 cells · ml−1) but is almost totally absent during winter. Photobacterium phosphoreum was detected in only a few winter samples. This seasonal pattern was repeated over a 23‐month sampling period. The abundance of B. harveyi is very highly correlated with the ambient surface water temperature. Growth rate studies indicate that B. harveyi is more temperature sensitive than P. fischeri when grown in a complex medium.
Potentiometric determination of copper complexation by phytoplankton exudates 1
Authors: Swallow K. C. , Westall J. C. , McKnight D. M. , Morel N. M. L. , Morel F. M. M.
Published: March 2010

Potentiometric copper titrations were done on culture media in which eight algal species, Thalassiosira pseudonana (3H), Ankistrodesmus falcatus, Chlamydomonas sp., Pediastrum sp., Staurastrum gracile, Gloeocystis gigas, Tribonema sp., and Cyclotella cryptica were grown to cell concentrations of 105–106 cells · ml−1. The results demonstrate that only G. gigas produces extracellular organic compounds that can measurably reduce the cupric ion activity in 1 × 10−6 M total copper.
A bacterial bioassay for measuring the copper‐chelation capacity of seawater 1
Authors: Gillespie Paul A. , Vaccaro Ralph F.
Published: March 2010

A relatively simple 14C tracer bioassay technique is described which uses a copper sensitive bacterium to measure the copper chelation capacity of seawater. Known increments of ethylenediaminetetraacetic acid are used to evaluate decreased bacterial inhibition accompanying reduced cupric ion activity. Ultraviolet irradiation and selective filtration of natural seawaters indicate that organic assemblages having molecular weights <10,000 are principally responsible for copper chelation. Copper chelation capacities ranged from 3 µg·liter−1 of copper for oligotrophic to 40 µg liter−1 of copper for eutrophic marine waters.
Collection of dinoflagellates and other marine microalgae by centrifugation in density gradients of a modified silica sol 1
Authors: Price C. A. , Reardon E. M. , Guillard R. R. L.
Published: March 2010

An improved medium is described, named “sorbitol seawater” (SSW), for the collection and concentration of marine phytoplankton by centrifugation into density gradients of silica. SSW is a partially synthetic seawater which is compatible with a modified colloidal silica (Percoll) and supports lowered but otherwise normal motility of several naked dinoflagellates, other fragile flagellates, diatoms, and a blue‐green alga. After isopycnic sedimentation into continuous or step gradients of Percoll in SSW, the organisms are concentrated into narrow zones specific to the banding densities of the alga and can be recovered more completely intact than from simple pelleting. Together with previously described methods, the medium should be useful in collecting morphologically and physiologically intact plankton from laboratory cultures and from marine waters.
UV absorption by gerrid cuticles 1
Authors: Douek Maurice , Goring David A. I.
Published: March 2010

Halobates is exposed to continuous insolation at the sea surface throughout its life. Although the UV‐absorbance spectrum of its dorsal cuticle (260–450 nm) is similar to those of related species from inshore and freshwater habitats where shelter from sunlight is available, the UV absorbance of the cuticle in a direction perpendicular to its outer surface is much higher in Halobates than in a mangrove‐dwelling Rheumatobates or a stream‐dwelling Gerris.
Sugar‐frosted Daphnia: An improved fixation technique for Cladocera 1
Authors: Prepas E.
Published: March 2010

Egg loss by preserved Daphnia was reduced from 35% to 10% by use of a chilled, as opposed to warm, solution of sucrose and Formalin.
A new tube sampler for crustacean zooplankton
Authors: George D. G. , Owen G. H.
Published: March 2010

A 10‐cm‐diameter flexible tube sampler for crustacean zooplankton is built in 5‐m sections and incorporates a pneumatically operated closing device and a stainless‐steel gauze funnel to filter the catch in situ. The sampler provides a quick, efficient way of collecting animals from the whole water column.
Correlation of carbon and nitrogen stable isotope ratios in sedimentary organic matter 1
Authors: Peters K. E. , Sweeney R. E. , Kaplan I. R.
Published: March 2010

Samples of organic matter separated from nearshore sediments of the Northeast Pacific are characterized by a linear correlation between 13C:12C versus 15N:14N. This correlation appears to represent the mixing of marine and terrestrial “end members” of refractory organic matter. Exceptions to the linear plot include organic matter from riverbeds draining agricultural areas, eutrophic lakes or lagoons with large algal populations, and some other exotic environments.
Interstitial water chemistry of anoxic Long Island Sound sediments. 2. Nutrient regeneration and phosphate removal 1
Authors: Martens Christopher S. , Berner Robert A. , Rosenfeld Jeffrey K.
Published: March 2010

The stoichiometry of nutrient regeneration in anoxic Long Island Sound sediments is examined through changes in the concentration of dissolved sulfate, ammonia, reactive phosphate, and other chemical species with depth in interstitial waters. In offshore sediments the mean ΔSO4:ΔNH4:Δ∑P ratio is —53:4.6:0.37; in shallow harbor sediment it is −53:19:3.3 and ΔNH4:Δ∑P ratios are half the offshore ratio. These indicated shoreward changes probably reflect more rapid deposition, and thus less preferential stripping of P and N from organic material before burial in shallow water harbor sediments, or selective stripping in the heavily bioturbated upper sediment layers offshore, or both. The effects of differential diffusion and adsorption of ammonia and phosphorus are considered.

Phosphate concentration maxima in ammonia‐ and phosphate‐rich shallow harbor sediments yield evidence for possible equilibrium with respect to vivianite, Fe3(PO4)2·8H2O, and struvite, MgNH4PO4·6H2O.
Cadmium in northeast Pacific waters 1
Authors: Bruland Kenneth W. , Knauer George A. , Martin John H.
Published: March 2010

Northeast Pacific water was collected by five different methods and the Cd in it was preconcentrated by both chelex‐ion exchange and chelation‐organic extraction techniques. All sampling and preconcentration methods yielded essentially the same data. Cadmium was very significantly correlated with phosphate and nitrate at all depths and it appears that the resulting equations, ng Cd · liter−1 = −3.6 + 34.9 (µmol PO4 · liter−1) and ng Cd · liter−1 = 5.1 + 2.45 (µmol NO3 · liter−1), can be used to predict oceanic Cd values.

Cadmium concentrations are lowest in nutrient‐depleted surface waters (4.5 ± 0.4 ng · liter−1) and greatest (125 ng Cd · liter−1) at the depths of the PO4 and NO3 maxima. Hence, Cd has one of the highest deep enrichment:surface depletion ratios (≃30) yet observed. Cadmium and phosphorus are also correlated in microplankton, and it is apparent that these organisms and their organic remains are a dominant factor in the biogeochemical cycling of this element.
A pattern analysis of Clear Lake phytoplankton 1
Authors: Sandusky James C. , Horne Alexander J.
Published: March 2010

Using results from synoptic measurements we developed a statistical frequency distribution more suitable for aquatic plankton than existing ones. We analyzed the synoptic data with this distribution and used the results to quantify phytoplankton spatial relations and to investigate controlling physical and ecological factors. We analyzed 43 sets of data (about 32 samples per set) representing 18 freshwater phytoplankton genera and obtained reliable results using three fitted parameters per set. We explicitly separated local and regional variability, thus avoiding overestimates of regional variability (patchiness) caused by counting individual cells of colonial or locally associated species as independent units. Patchiness estimates showed significant between‐species variations related to nutrient variability, relative species dominance, and species sensitivity. Pooling cell frequencies for related species reduced patchiness estimates. This implies that comparisons of spatial relations between biotic and abiotic parameters underestimate phytoplankton (biotic) spatial organization when several species are present.
Wind events and food chain dynamics within the New York Bight 1, 2
Authors: Walsh John J. , Whitledge Terry E. , Barvenik Frank W. , Wirick Creighton D. , Howe Steven O. , Esaias Wayne E. , Scott Jon T.
Published: March 2010

Time series of wind, current, nutrients, chlorophyll, and zooplankton are used to examine the effect of storm events on the food chain dynamics of the New York Bight. Storms cause dilution of phytoplankton concentration in the vertical plane, but lead to aggregation of chlorophyll in the horizontal field. Nutrients are made available with onshore flow in response to wind events favorable for upwelling. A series of nutrient budgets suggest that storm‐induced mixing and upwelling of nitrate may satisfy at least 33% of the productivity demand of this system. Examples of the biological response to storms are drawn from 20 cruises during January, March, April–May, and August–September 1974, 1975, 1976, and 1977 under mixed and stratified conditions of the water column. The interaction of storms and seasonal stratification suggests predictable structure and frequency of chlorophyll distribution across the shelf which may influence both the survival strategies of herbivores and the loci of energy transfer to the rest of the food chain.
Experimental measurements of nitrogen remineralization in coastal waters 1
Authors: Harrison William G.
Published: March 2010

Ammonium remineralization was measured in the euphotic zone of two coastal areas using a 15N isotope dilution technique. Remineralization fluxes were high in both areas and often exceeded assimilation fluxes. A strong positive correlation between ammonium remineralization and ammonium and carbon dioxide assimilation suggests a close coupling of photosynthesis and nitrogen recycling. Regenerative fluxes decreased with depth and with distance offshore, but to a relatively lesser extent than did assimilative fluxes. Turnover times for remineralzation of utilizable organic nitrogen were estimated to be from 3 to 16 clays. Size fractionation experiments and estimates from the literature suggest that microplankton (<183 µcm) may have been the primary nitrogen remineralizers.
Steady state growth and ammonium uptake of a fast‐growing marine diatom 1
Authors: Goldman Joel C. , McCarthy James J.
Published: March 2010

A fast‐growing marine diatom Thalassiosira pseudonana (3H) was grown under NH4+‐limited steady state conditions in continuous culture. Growth rate could not be described as a function of external or residual NH4+ because of analytical limitations in measuring NH4+ concentrations <0.03 µg‐atom N · liter−1. Neither did the data fit the internal nutrient model of Droop because the washout growth rate (µ̂) under N limitation is substantially less than the maximum growth rate term used in the Droop expression (µ̄). The ratio of the minimum (kQ) to the maximum (Qm) cell quota was the key term in determining the ratio µ̂:µ̄, and hence the applicability of the Droop expression. For limiting nutrients such as vitamin B12 and P, µ̂ ~ µ̄, and the expression is applicable; but, when µ̂ < µ̄, as for N and Si, the usefulness of the expression is diminished, and when µ̄ → ∞, as for inorganic carbon, the Droop equation is completely invalid. In a general sense the usefulness of the Droop expression diminishes as the limiting nutrient:cell weight ratio increases. The generality of the concept of cell “shift up,” or increasing kQ and µ̄ with increasing growth rate, is questioned as no evidence for this phenomenon was found in T. pseudonana. Moreover, the demonstration of discontinuities in kinetic curves of Q vs. µ does not a priori imply that the coefficients kQ and µ̂ are variable.
Photorespiration and CO2 compensation point in Najas flexilis1
Authors: Hough R. Anton , Wetzel Robert G.
Published: March 2010

The response of net photosynthesis, light:dark respiration ratio, and CO2 compensation point to oxygen manipulation and to inhibitors of glycolate metabolism confirms earlier evidence that photorespiration occurs in Najas flexilis and can influence its productivity. Estimates of the CO2 compensation point are similar to those for several other submersed angiosperms which cannot reduce total aqueous CO2 concentration much below air equilibrium levels.
The uptake, retention, and release of ammonium by reef corals 1
Authors: Muscatine L. , D'Elia C. F.
Published: March 2010

Of several genera tested, only those Pacific reef corals symbiotic with zooxanthellae take up and retain ammonium. Uptake and retention are enhanced by light, and the normal daylight period is sufficient to sustain ammonium retention during the night. Ammonium uptake kinetics for several species indicate that a two‐process mechanism may be involved. If a correction is made for diffusion, uptake kinetics can be characterized by the Michaelis‐Menten equation.
Laboratory studies of ingestion and food utilization in lobate and tentaculate ctenophores 1
Authors: Reeve M. R. , Walter M. A. , Ikeda T.
Published: March 2010

Ctenophore ingestion rates are linearly related to food density up to concentrations much higher than those usually assumed to be representative of the natural environment. Daily rations in excess of 1,000% of their body weights at high prey densities are matched by growth rates characteristic of phytoplankton (daily doublings). Digestive efficiencies >70% were recorded at moderate prey densities. Growth efficiencies rarely exceed 10% because the bulk of assimilated food (up to 80% of that ingested) is required for the energy metabolism of these organically dilute (carbon 2% of dry wt) creatures. Ctenophores may be at a competitive disadvantage at low food densities compared to predators such as chaetognaths, but at high food densities the reverse is true. Population explosion among ctenophores, and consequent decimation of’ other zooplankton, is well within their physiological means. In addition to regulating herbivore excesses and stimulating recovery of phytoplankton (by predation and rapid remineralization of nutrients), ctenophores are self‐regulated by being unable to maintain themselves when food supplies drop hack to moderate levels.
Predicting particle selection by deposit feeders: A model and its implications 1
Authors: Taghon Gary L. , Self Robert F. L. , Jumars Peter A.
Published: March 2010

A feeding model for a generalized, benthic deposit feeder is derived from a filter‐feeding model and used to predict how such a deposit feeder would adjust its feeding to maximize its net energy gain. Under the assumption that deposit feeders are utilizing the bacterial fraction of the sediment or other surface organic coatings as food, the model predicts that the smallest particles should always be ingested, while the selection of larger particles depends on several parameters, including gut passage time and assimilation efficiency of the deposit feeder. The model also predicts relationships among particle size selection, assimilation efficiency, gut passage time, gut volume, and particle rejection costs.
Cellulose digestion in Mysis stenolepis and its ecological implications 1
Authors: Foulds J. B. , Mann K. H.
Published: March 2010

Mysis stenolepis was allowed to filter feed on suspensions of 14C‐labeled raw cellulose and hay particles, with and without a coating of microorganisms. Assimilation efficiencies were from 30% to 50% for cellulose and from 20% to 35% for hay. In both cases, assimilation efficiencies were higher for sterile food than for nonsterile food.
The herbivorous habits of Mysis relicta in Lake Michigan 1
Authors: Bowers James A. , Grossnickle Nevin E.
Published: March 2010

Herbivorous feeding by Mysis relicta on three size fractions of natural phytoplankton from Lake Michigan was measured from the change in concentration of chlorophyll a. Mysis fed primarily on the largest size fraction. When offered only the largest size fraction, Mysis fragmented the material and the fragments were observed as increases in the smallest size fraction. Diaptomus ashlandi, which could feed only on the smallest size fraction, is a possible recipient of such fragmented cells or chains. A simple compartmental model indicated that filtering rates of Mysis were significantly greater on the largest than on the smallest fraction, and that during feeding 5–6% of the largest size fraction was broken up into the smallest size fraction. Mysis may feed on large phytoplankton by migrating at night into a chlorophyll a maximum in the thermocline containing mostly the largest size fraction. Moonlight inhibited the ascent of Mysis at night and may indirectly affect phytoplankton mortality due to mysid grazing.
Energy flux in the pelagic ecosystem: A time‐dependent equation
Authors: Silvert William , Platt Trevor
Published: March 2010

A time‐dependent equation has been developed for the size structure of the pelagic food chain in the sea. It is based on accepted, quantitative relationships for the weight dependence of metabolism and growth. The general solution is given.
Relationship of rainfall and lake groundwater seepage 1
Authors: Peterka John J.
Published: March 2010

Correlations were found be tween mean daily rainfall and groundwater inflow rate and between the rate of groundwater inflow and N and P inflow to a senescent lake during summer. A simple method of collecting and measuring groundwater inflow was reproducible at very low inflow rates. The water collected by this method was similar in P concentration to groundwater but higher in N concentration.
The distribution and form of phosphorus in North Atlantic Ocean deep‐sea and continental slope sediment 1
Authors: Morse John W. , Cook Neil
Published: March 2010

The distribution of various forms of phosphorus and their association with other sediment components were determined in cores collected from the continental shelf off the Eastern United States and the central North Atlantic Ocean. The results indicate that apatite P is the most important phosphatic component and that its abundance closely follows calcium carbonate in deep‐sea sediments. Nonapatite inorganic P is closely correlated with acid‐leachable Fe and Mn. Organic P was most significant in reducing continental slope sediments, which also contained the highest amounts of organic C. Concentrations of dissolved reactive phosphate are similar to those found in shallow water sediments of the same general type.
Some factors influencing size of Diaptomus shoshone1
Authors: Maly Edward J.
Published: March 2010

Numerous measurements were made of Diaptomus shoshone inhabiting a small Colorado pond. Sizes of copulating individuals were compared to overall individual sizes. Larger individuals of both sexes mated more often, and overlap in size between sexes is less than expected if size distributions of the sexes were normal. The results suggest that although interspecific relationships (competition and predation) place absolute limits on the size of this species, intraspecific relationships affect size within these limits.
Isotope hydrology of inland sabkhas in the Bardawil area, Sinai
Authors: Gat J. R. , Gat J. R.
Published: March 2010

The changes in stable isotope composition of inland sabkhas can throw light on the hydrologic mechanisms which operate in these systems. Inflow waters were found to be of meteoric origin. Immediately after local rain, water drains from surrounding sand dunes onto the top of the salt crust, dissolving it. Further inflow of waters keeps the sabkhas inundated for weeks, but the different sabkhas were found to be open to varying degrees to the inflow of groundwaters and to outflow of brines into bottom sediments.
pH fluctuation in an intertidal beach in Bermuda 1
Authors: Gnaiger Erich , Gluth Gerhard , Wieser Wolfgang
Published: March 2010

Unusually high pH values up to 9.6 measured during low tide in a calcareous sandy beach were correlated with high in situ temperatures. Daily fluctuations of up to 1.5 units are limited to the topmost layer of sediment. Light, by controlling photosynthesis, is the causal factor in determining high pH at the surface; subsurface sediments do not respond to experimental light changes. Indications of such fluctuations are lacking in the literature. These fluctuations could influence community respiration.
Volatile chloro‐ and bromocarbons in coastal waters1
Authors: Helz George R. , Hsu Rong Y.
Published: March 2010

Contaminated coastal waters can contain nanomolar levels of C1 and C2 halocarbons originating through in situ synthesis from chlorine and through waste discharge. Haloforms are the major volatile products formed from chlorine. In freshwaters, CHCl3 dominates with lesser amounts of CHBr3 and the mixed Cl–Br haloforms; however, above about 5 g · kg−1 salinity, CHBr3 is virtually the only product when typical chlorine doses (10–100 µM) are used. On a molar basis, >4% conversion of chlorine to haloforms was observed in some experiments. Samples from the Back River estuary (Maryland), which receives effluent from a very large urban wastewater treatment plant, contained CH2Cl2, CHCl3, CCl4, CCl2 = CHCl, and CCl2=CCl2 at concentrations exceeding 1 nM. Even when winter ice cover minimized loss by volatilization, downstream mixing was nonconservative, suggesting that chemical or biological degradation processes occur. Under normal circumstances, however, volatilization followed by chemical degradation in the atmosphere is probably the most important loss mechanism. Data on possible biologic effects of these compounds are critically needed.
Effect of complexation by natural organic ligands on the toxicity of copper to a unicellular alga, Monochrysis lutheri1
Authors: Sunda William G. , Lewis Jo Ann M.
Published: March 2010

The effect of copper on the division rate of a unicellular alga, Monochrysis lutheri, was tested in media with different concentrations of natural organic ligands. Filtered river water containing a high concentration of organic matter was added in different proportions to culture media to vary the level of copper complexation. Increased binding of copper by natural ligands was associated with decreased toxicity of a given concentration of added CuSO4. The decrease in copper toxicity with increasing complexation could be explained quantitatively in terms of a dependency of toxicity on the concentration of free cupric ion. These results indicate that complexation of copper by organic ligands should considerably influence the toxicity of copper in natural waters through the effect of such eomplexation reactions on free cupric ion concentrations.
Satellite observations of calcium carbonate precipitations in the Great Lakes1
Authors: Strong Alan E. , Eadie Brian J.
Published: March 2010

Reflectance patterns apparently from calcium carbonate (CaCO3) precipitation have been mapped in the Great Lakes using satellite multispectral imagery. The milky water phenomenon (“whiting”) occurred regularly in summer and fall during the period studied, 1972–1975, in Lakes Ontario, Erie, and Michigan but not in Superior and Huron. In situ data provide nearly irrefutable evidence that these whitings are calcareous. They are attributed to supersaturation of CaCO3 during periods of thermal stratification and are most intense in the warmer areas of the lakes. The whitings are maximal several meters below the surface and are undoubtedly significant with respect to light transmission, affecting the euphotic zone and thereby photosynthetic production. They may serve as lakewide markers in synoptic analysis of large‐scale epilimnial horizontal motions.
Spatial heterogeneity of phytoplankton biomass and related factors in the near‐surface waters of an exposed coastal embayment
Authors: Therriault Jean‐Claucle , Piatt Trevor
Published: March 2010

In the surface layer of an exposed marine embayment, complex spatio‐temporal interactions characterized the variances in phytoplankton biomass and related factors observed during 1 year. There is evidence that differential grazing by zooplankton is an important factor in the creation and maintenance of spatial heterogeneity in the phytoplankton.
Spatial variability of phytoplankton turnover in relation to physical processes in a coastal environment
Authors: Therriault Jean‐Claude , Lawrence Donald J. , Piatt Trevor
Published: March 2010

For the near‐surface layer of an exposed coastal embayment, wind stress is shown to be a satisfactory index of turbulence as measured by high frequency current fluctuations. A strong coupling is demonstrated between this index of turbulence and the spatial variance of phytoplankton production efficiency (P:B). Physical processes dominate over biological and chemical processes in controlling phytoplankton variability for wind velocities greater than 5 m · s−1, which occurred 40% of the time.
Relationship of dissolved inorganic carbon to macrophyte photosynthesis in some Italian lakes1
Authors: Adams Michael S. , Guilizzoni Piero , Adams Susan
Published: March 2010

Photosynthesis of Myriophyllum spicatum was measured (14C technique) in the field in waters from eight Italian lakes having different dissolved inorganic carbon (DIC) concentrations and in two mixtures of water from two of the lakes. In the experiments, in which there were some differences in pH and light, photosynthetic response to DIC fit a Michaelis‐Menten relationship, demonstrating the importance of DIC as a factor affecting productivity of these aquatic plants.
Adaptations to fluctuating irradiance by natural phytoplankton communities1
Authors: Jones Roger I.
Published: March 2010

Evidence is presented for the operation in nature of two mechanisms by which phytoplankton are able to maximize their effective photosynthetic output in the face of changing irradiance. Only one can be considered to represent true adaptation to changing irradiance; the other apparently depends on concurrent temperature changes.
Distribution, abundance, and metabolic states of microorganisms in the water column and sediments of the Black Sea1
Authors: Karl David M.
Published: March 2010

The vertical distribution, abundance, and metabolic states of microorganisms have been measured within the water column of the Black Sea. Samples collected from the O2–HS− interface revealed a vertically restricted layer (<20–30 m) of metabolically active cells. Within the anoxic portion of the water column (200–2,100 m), ATP concentrations were 5–10 times greater than in oxygenated environments of comparable depth; biomass and various metabolic activities increased with increasing water depth, implying a vertical gradient in specific organic substrates required for bacterial growth and metabolism.

The vertical distribution of ATP was also measured in two sediment cores raised from the western basin of the Black Sea. The ATP concentration within the uppermost sediment layer (0–10 cm) was 4 orders of magnitude greater than in the overlying water column, on a per volume basis (150 ng ATP · cm−3 for the sediments, vs. 10 ng ATP · liter−1 for the water column). Scanning electron micrographs are presented depicting early stages in the diagenesis of framboidal iron sulfide.
Vertical distribution of Calanus hyperboreus in the central Arctic Ocean1
Authors: Dawson John K.
Published: March 2010

The vertical distribution of Culanus hyperboreus was determined for a 23‐month period from net samples collected from T‐3 Ice Island in the central Arctic Ocean. Distributions of copepodite stages were similar, but dissimilar to that of the adults. The depth range of the copepodites was 300–500 m, except during summer when they rise to the surface. The adult female population sank gradually from 100 to 300 m in the spring. During summer, females were at the surface and by fall they were centered at about 150 m, where they remained throughout winter. Adult males were centered deeper (400–700 m) than the females and were present only during spring and early summer.

Calanus hyperhoreus appears to have a generation length of at least 3 years in the central Arctic Ocean.
Length and weight relationships of Acartia clausi from Narragansett Bay, R.I. 1
Authors: Durbin Edward G. , Durbin Ann Gall
Published: March 2010

Changes in the cephalothorax length and dry weight of Formalin‐preserved copepodite and adult Acartia clausi were followed from 12 March–1 June 1976 and naupliar weights and lengths determined for one sample. Preservation in Formalin caused a significant loss of dry weight, carbon, and nitrogen in adult females, mostly during the first 24 h, but did not significantly affect the C:N ratio or the cephalothorax length of the animals.

Length and weight were inversely related to seawater temperature at the time of sampling. As the animals became older this relationship was increasingly affected by their past temperature history. Separate linear relationships between log length and log weight were observed for the nauplii, the CIs, the CII–CVs, and the adults, making it possible to estimate the weight of individual stages from measurements of length.

Animals collected on the same day from different stations sometimes showed significant differences in weight for a given length. Such differences could be more clearly expressed by calculation of a condition factor relating weight to the cube of cephalothorax length. The differences in the condition factor appeared to be related to food availability and such differences may be even more apparent when weights of live animals are examined.
The enigma of Daphnia death rates1
Authors: Prepas E. , Rigler F. II.
Published: March 2010

Birth rates, rates of population change, and mortality rates were computed for Daphnia pulex and Daphnia rosea collected at three separate stations in. 2.5‐ha meromictic Crawford Lake. Birth and death rates for the same species at the three separate stations, or at the same station but living at slightly different mean depths were substantially different. A correction for tow net efficiency for young and adult animals increased birth rate values by 40%.

Mean finite birth rate, B, for Daphnia in a thermally stratified lake is calculated from the relation
urn:x-wiley:00243590:media:lno19782350970:lno19782350970-math-0001
where for each stratum, s, E is number of eggs, D is egg development time, N is number of animals, and n is number of strata. An assumption of this formulation is that all individuals in the population behave similarly, hut at Crawford Lake D. pulex behaves like two separate populations for at least part of the year.

High death rates were calculated for D. rosea in midsummer. A comparison of observed neonates with expected neonates during this period led to the conclusion that most mortality in the population occurs either in late embryos or at hatching.