bluuebunny/crossref_metadata_2025 huggingface dataset:
The assumptions and rationales of a computer model of phytoplankton population dynamics1
Authors: Lehman John T. , Botkin Daniel B. , Likens Gene E.
Published: March 2010

Predictions of phytoplankton growth dynamics and nutrient assimilation by a computer simulation model are consistent with studies of field and laboratory populations. The model simulates population dynamics and gross physiology of phytoplankton species in the epilimnion of a lake where algal growth is subject to temperature, light, and nutrient constraints and includes luxury consumption, end‐product inhibition of both carbon fixation and nutrient uptake, and species‐specific differential efficiencies of nutrient assimilation. C: P, C: N, and N: P ratios of the algal cells respond to changes in external nutrient conditions, and nutrient storage by the cells permits biological effects of nutrient pulses to be evident long after assimilation of dissolved nutrients forces the pulses to decline. Species succession results when abundances of specific taxa decline due to such factors as sinking or grazing, which assume overriding importance when cell division rates are slowed by chemical or physical limitations. The physiological tenets and limiting assumptions of the model have been used to formulate patterns of competition among species for light and nutrients in natural systems and to predict temporal changes in plankton biomass and species composition.
Horizontal distribution of planktonic diatoms in Green Bay, mid‐July 19701
Authors: Holland Ruth E. , Claflin Larry W.
Published: March 2010

A synoptic survey of Green Bay was undertaken in mid‐July 1970 to determine the horizontal distribution of major species of planktonic diatoms.

Principal component analyses of R‐correlation and covariance matrices, and four methods of factor analysis described a general bipolar axis which grouped Melosira granulata, Stephanodiscus spp., Cyclotella meneghiniana, and Stephanodiscus niagarae at one pole and Fragilaria crotonensis, Asterionella formosa, Tabellaria flocculosa, and Cyclotella comta at the opposite pole.

Cluster analysis of diatoms defined one major group, which predominated in the extreme southern part of the bay, as certain centric species plus the araphid Fragilaria capucina. Two other groups, consisting primarily of other araphids and species of the genus Cyclotella, characterized the rest of the bay.

Cluster analysis of 68 stations, based on distribution of diatoms, divided the bay into three major areas: extreme southern Green Bay, southern and eastern Green Bay, and northern and western Green Bay.
Nitrogen fixation and uptake of combined nitrogenous nutrients by Oscillatoria (Trichodesmium) thiebautii in the western Sargasso Sea1
Authors: Carpenter Edward J. , McCarthy James J.
Published: March 2010

In the western Sargasso Sea in early autumn the standing crop of Oscillatoria thiebautii at nine stations averaged 640 × 105 cells m−2 with a maximum population of 11.8 × 105 cells m−3 at 25 m. Population density at 175 m averaged only 6% of that at 25 m. N2 fixation was greatest at 1‐m depth, 0.069 pg cell−1 h−1, and at 50 m decreased to 9% of that at 1 m. Highest recorded N2 fixation, 0.20 pg cell−1 h−1, was at the southernmost station. Average N2 fixed per square meter of sea surface in the upper 50 m was 2.0 µg N m−2 h−1. When compared with other N inputs to the surface waters of the western Sargasso Sea, N2 fixation by Oscillatoria seems negligible.

Results of 15N‐labeled NH4+, NO3−, and urea uptake experiments indicate that O. thiebautii is barely able to utilize these nutrients at the concentrations present in the euphotic zone. Doubling times (Td) for cellular nitrogen by N2 fixation and NH4+ uptake together are in the order of 40 to 110 days. An uptake curve for NH4+ yielded a K. of 6.7 µg‐atoms N liter−1, a value about an order of magnitude greater than that found for other open‐ocean phytoplankters.

We were unable to isolate any N2‐fixing bacteria from O. thiebautii.
Steady state analysis of nitrate‐ammonium assimilation by phytoplankton1,2
Authors: Bienfang Paul K.
Published: March 2010

The ammonium:nitrate delivery ratio to cells of Dunaliella tertiolecta in continuous culture had no effect on the ambient nitrate concentrations at steady state, indicating that the assimilation of these radicals is competitive, not suppressive, under nitrogen limiting conditions. The physiological parameters, C:cell and Chl:cell, were invariant over the range of delivery ratios. Cellular growth potential and yield coefficients (N:cell and N:C) showed a linear decline with increasing ammonium:total nitrogen input ratios, supporting the hypothesis that NH4+ is not stored intracellularly. At low NH4+ contributions the yield coefficients displayed characteristics not predictable from considerations of solely ammonium or nitrate limited growth. The N:cell ratio is an excellent measure of the cellular growth potential resulting from intracellular reserves.
Nitrate uptake in marine phytoplankton: Comparison of half‐saturation constants from seven species1
Authors: Falkowski Paul G.
Published: March 2010

Seven species of marine phytoplankton were assayed for the presence of a NO3−,CI−‐activated ATPase, thought to be associated with the cell membrane. Only the single dinoflagellate tested, Amphiclinium carterae, failed to show ATPase activity, while the specific activity of the enzyme ranged over one order of magnitude in the other species examined. It is suggested that the enzyme is primarily responsible for the active transport of NO3− across the plasmalemma and furthermore the Km for NO3− activation of the enzyme is physiologically manifested by Ks values for NO3− uptake by whole cells. The enzymatic mechanism may explain the observed Michaelis‐Menten kinetics for NO3− uptake.
Some aspects of prey capture by Chaoborus larvae1
Authors: Swift Michael C. , Fedorenko Alice Y.
Published: March 2010

The effects of prey size, shape, and locomotion on capture, ingestion, and handling time were investigated in second‐, third‐, and fourth‐instar larvae of Chaoborus americanus and Chaoborus trivittatus from Eunice Lake, British Columbia. Before contact, densities and swimming speeds of predators and prey determine the number of interactions and hence availability. After contact is made, successful capture is determined largely by prey size and shape. Vulnerability increases as prey size decreases for both copepods and cladocerans. Although larvae are equally successful when striking at copepods or cladocerans, once contact with the prey is made copepods are handled much more efficiently than cladocerans of the same size. Size incompatibility between predator and prey is only important in prey capture at the extremes of the size ranges of both.
Seasonal temperature effects and predicting development rates of marine copepod eggs1
Authors: Landry Michael R.
Published: March 2010

Egg development rates of the marine copepod Acartia clausi are affected by the temperature history of the female parent. The eggs from animals collected during winter (8–10°C) have significantly faster development rates under summer conditions (15–20°C) than those collected during summer (18–20°C). Adaptation of winter acclimated animals to summer conditions is a slow process requiring longer than one generation at 20°C. Others have suggested that the egg development rates of different species of marine copepods from the arctic to the tropics are related to temperature by different functions: when the effects of metabolic depression at the low and high limits of a copepod’s temperature range are considered, the data support the alternative proposal that the relative rates of egg development for nine species of arctic‐temperate marine copepods follow a common temperature function.
The geochemical cycle of arsenic in Lake Washington and its relation to other elements1
Authors: Crecelius Eric A.
Published: March 2010

Abnormally high arsenic concentrations (> 200 ppm dry wt) in the surface sediments of Lake Washington are attributed to atmospheric input of partially soluble arsenic‐rich dust from a copper smelter 35 km upwind and removal of dissolved As from the lake water by bacteria or an inorganic reaction.

The suspended matter in the deeper lake water contains 9% iron, 8% manganese, and 350 ppm arsenic. Cores dated by 210Pb indicate that As levels began to increase in the sediments when the smelter began operation in 1890.

An arsenic budget for the lake shows equal supplies from the atmosphere and from rivers, and removal by outflowing water (45%) and by accumulation in the sediments (55%). A similar cycle was observed for antimony which is released by the smelter in much smaller amounts than arsenic.

About two‐thirds of the As in rain and lake water was in the form of arsenate; however, in the interstitial water 55% of the dissolved As was present as arsenite and a few percent as dimethylarsinic acid.
The fluxes of elemental carbon in coastal marine sediments
Authors: Griffin John J. , Goldberg Edward D.
Published: March 2010

Management practices in the control of forest and brush fires off California and British Columbia appear to have had little effect on the fluxes of elemental carbon (microcrystalline graphite) in the marine environment. Part of the carbon produced during the burning process can be transferred to the oceans via the atmosphere immediately following combustion. Another part is temporarily accommodated in surface soils and may later enter the ocean via the atmosphere or terrestrial runoff.
Mercury concentrations in open‐ocean waters: Sampling procedure1
Authors: Fitzgerald William F. , Lyons W. Berry
Published: March 2010

A PVC sampler was found suitable for collecting seawater samples at depth for Hg determinations. Mercury concentrations averaged 8 ± 3 ng liter−1 in surface seawater in the northwest Atlantic Ocean.
An explanation for the Florida east coast Gymnodinium breve red tide of November 19721
Authors: Murphy E. B. , Steidinger K. A. , Roberts B. S. , Williams J. , Jolley J. W.
Published: March 2010

The first documented Florida east coast Gymnodinium breve red tide is attributed to an unusual Loop Current pattern. Satellite and ground data indicate that the November incident was seeded by a red tide detected in late September 1972 in southwest Florida waters; southwest inshore waters flowed directly south through the Florida Keys, carrying low to moderate concentrations of G. breve which were concentrated and transported to the east coast by unusual current configurations.
Uptake and migration of tracers in lake sediments1
Authors: Lerman A. , Lietzke T. A.
Published: March 2010

Mathematical solutions are given for an equation describing transient and steady state concentrations in lake water and sediments, in the presence of adsorption, decay, sedimentation, and diffusion. The results of the model are compared with the distributions of two tracers, 90Sr and 137Cs, in the sediments of Lakes Erie and Ontario. Adsorption of the two tracers by sediment particles, supported by experimental data, can be treated as a linear exchange reaction. 90Sr is adsorbed less strongly than 137Cs by sediments, and this feature accounts for the greater depths of 90Sr occurrence in lake sediments. Distribution of the radionuclide activities in sediments is compatible with a model based on mean steady input to the lakes for 16 years (1953–1969), and the following values of diffusion coefficients in pore waters: for 90Sr, 2 × 10−6 to 4 × 10−6 cm2 s−1, and for 137Cs, 2 × 10−5 cm2 s1. An additional transport mechanism in sediments, sedimentation, is more significant in Lake Erie (0.3–0.6 cm yr−1, according to the model) than in Lake Ontario (0.05 cm yr−1) . Conditions are outlined under which the fluxes from lake water to sediments are important in the chemical balance of medium and large lakes.
A simple diffusion model of the mean field distribution of soluble materials in the Great Lakes
Authors: Boyce F. M. , Hamblin P. F.
Published: March 2010

In cases where the time scale of interest is long compared with the time scales of the principal energy‐bearing components of water movements, the movement of a soluble contaminant may be represented by a simple diffusion equation with an effective constant horizontal diffusion coefficient, KII. A simple steady state model of the concentration field in the lake of a soluble contaminant introduced on the shore is developed and applied to a situation for which there are appropriate experimental data, the distribution of chloride ion in the central basin of Lake Erie. A horizontal diffusion coefficient, KII, appropriate for basin‐wide diffusion phenomena in the Great Lakes and long time scales may be estimated from experimental data.
Quantitative degradation of chlorophyll by a marine herbivore1
Authors: Shuman F. Randolph , Lorenzen Carl J.
Published: March 2010

In laboratory grazing experiments, primarily with Calanus sp. feeding on Coscinodiscus angstii, the decrease in chlorophyll concentration and the increase in pheophorbide concentration was determined. The average conversion of chlorophyll to pheophorbide was 66% on a weight basis and 100% on a molar basis. Some chlorophyll was found in fecal pellets. The specific absorption coefficient of pheophorbide in 90% acetone at 667 nm was 53.5 (g‐cm)−1, about the same as that of pheophytin under the same conditions. Previously published equations for the determination of pheophytin can be used for pheophorbide.
Phosphorus quota and the chlorophyll: carbon ratio in marine phytoplankton1
Authors: Tett Paul , Cottrell Janet C. , Trew D. O. , Wood B. J. B.
Published: March 2010

From work on nutrient limited algal growth an equation was derived relating algal chlorophyll:carbon ratio (ccr) to cell nutrient quota (Q).

urn:x-wiley:00243590:media:lno19752040587:lno19752040587-math-0001

where r/µ′max is a constant representing the ratio of specific respiration rate to maximum specific growth rate, k′q is an (apparent) subsistence quota, and ccrmax is a third constant —the value of the Chl:C ratio when Q/k′q = µ′max/r. This hypothesis was investigated using data from the spring phytoplankton increase in Loch Creran in 1973. The quota was measured as the phytoplankton P:C atomic ratio, and a regression method was used to estimate detrital phosphorus and carbon in order to correct measurements made of total particulate material. Although phosphorus did not appear to be the single limiting nutrient, and hence the estimates of k′q were of an apparent rather than true subsistence quota, the equation was shown to be a reasonable description of the relation between the chlorophyll, phosphorus, and carbon contents of the phytoplankton over two periods of 3–4 weeks each. During the period of phytoplankton increase k′q and ccrmax were estimated as 0.014 atom P/atom C and 0.083 g Chl/g C; during the period of decline the respective values of these constants were 0.0062 and 0.040.
Transport limited nutrient uptake rates in Ditylum brightwellii1
Authors: Pasciak Walter J. , Gavis Jerome
Published: March 2010

The analysis of diffusional transport limitation of nutrient uptake rates by phytoplankton, derived earlier for spherical cells, is extended to include, in an approximate manner, cylindrical and disk‐shaped cells. Transport limitation of nutrient (NO3− and NO2−) uptake rates by the marine diatom, Ditylum brightwellii, was demonstrated experimentally at low nutrient concentrations in quiescent media. The effect of transport limitation was decreased by mixing and eliminated completely when the organism was cultured in a medium being sheared at a high enough rate. It also disappeared at high enough nutrient concentrations.
The influence of tidal flux on microbial biomass in salt marsh creeks1,2
Authors: Erkenbrecher Carl W. , Stevenson L. Harold
Published: March 2010

The fluctuations of aerobic, heterotrophic bacteria, particulate organic carbon (POC), and adenosine triphosphate (ATP) in the water system of a salt marsh were investigated at two marsh creeks. Both reached maximum densities of bacteria just before low tide. In a typical study, however, the mean concentration at station 1 over a tidal cycle was an order of magnitude greater than at station 2. POC increased twofold to fourfold during ebbtide in both systems. ATP concentrations at station 2, during ebbtide, increased about fourfold, and the fraction of the total carbon regarded as “living” ranged from 2–24%.
Studies on glycolic acid metabolism by freshwater bacteria1
Authors: Wright Richard T.
Published: March 2010

Measurements of uptake and mineralization of 14C‐labeled glycolic acid by freshwater heterotrophs showed that respiration (mineralization) accounts for 69% of total uptake, and that the heterotrophic potential (Vmax) for glycolate is comparable with that for other commonly used substrates. Bacteria cultured from lake water showed uptake and mineralization patterns similar to those from the natural plankton. Enrichment of lake water with glycolic acid resulted in measured disappearance of the glycolic acid, in agreement with rates predicted by uptake kinetics, but bacterial response was slow and independent of added glycolate concentration. Under natural conditions the heterotrophic bacteria prevent glycolate from accumulating by mineralizing most of it to CO2 soon after it is released by algae.
An electrophoretic study of the antarctic zooplankter Euphausia superba1
Authors: Ayala F. J. , Valentine James W. , Zumwalt G. S.
Published: March 2010

Genetic variability has been estimated for a large population of the antarctic krill, Euphausia superba, by gel electrophoresis. Of 36 loci studied, 21 (58.3%) exhibit allelic variation. An average individual is heterozygous at 5.8% of the loci, a moderately low level of variability when compared to benthic invertebrates. Low to moderately low genetic variabilities are previously recorded from benthic invertebrates in environments with highly seasonal trophic resources, and E. superba fits this relationship.
Nitrogen fixation in Flax Pond: A Long Island salt marsh1
Authors: Whitney D. E. , Woodwell G. M. , Howarth R. W.
Published: March 2010

Nitrogen fixation was measured by the acetylene reduction technique during summer 1973. Rates of fixation in the top 4 cm of all sediments ranged from 12 to about 800 µg N fixed m−2 h−1. Fixation diminished with depth with none at 20 cm or below. Blue‐green algal mats fixed at rates that ranged from 260–8,900 µg N m2 h−1. No fixation was detected in the tidal water column, but rates of 8.6–4,800 µg N liter−1 h−1 occurred in small stagnant pools on the marsh surface. Rates of fixation appeared not to vary between day and night.
Densities of bacteria and fungi in coastal surface films as determined by a membrane‐adsorption procedure1,2
Authors: Crow S. A. , Ahearn D. G. , Cook W. L. , Bourquin A. W.
Published: March 2010

A membrane‐adsorption technique for counting surface slick microbial populations was evaluated. The simple procedure gave bacterial and fungal populations several orders of magnitude greater than those previously reported for surface slicks.
An evaluation of ATP estimations of bacterial biomass in the presence of phytoplankton1
Authors: Jassby Alan D.
Published: March 2010

The reliability of estimating bacterial biomass from total ATP levels and phytoplankton counts was investigated. A statistical analysis indicated that, even disregarding systematic error, the propagation of random errors renders the procedure reliable only in a small class of natural waters. Data from Castle Lake, California, demonstrate that systematic error of large magnitude is also present.
Enrichment experiments for determining nutrient limitation: Four methods compared1
Authors: Gerhart David Z. , Likens Gene E.
Published: March 2010

Four nutrient bioassay techniques were compared in studies of an oligotrophic, soft‐water lake in New Hampshire. Enrichments of large polyethylene enclosures, continuous cultures of the natural phytoplankton community, and long term 14C bioassays agree in demonstrating that nitrogen and phosphorus limit phytoplankton growth in this lake. However, in short term (4–30 h) 14C bioassays, nitrogen and phosphorus enrichments did not stimulate phytoplankton production. Care should be exercised in extrapolating results from short term, bottle bioassays to measures for controlling eutrophication.
Measurement of the apparent pH of seawater with a combination microelectrode1
Authors: Zirino Alberto
Published: March 2010

A method for precisely measuring the apparent pH of seawater, using a microelectrode and a specially designed cell, is described. The cell requires a 25‐ml sample, reaches equilibrium in 6 min or less, and its precision in routine use at sea was ± 0.0026 pH units.
An evaluation of sediment trap methodology
Authors: Kirchner W. B.
Published: March 2010

Five sediment traps with collecting areas ranging from 8 to 1,465 cm2 collected the same amount of material, as measured by dry weight, ash weight, and phosphorus content, on a unit area basis. Variances from different size traps were not significantly different. These results are presented as further illustration that traps are a meaningful technique for measuring sedimentation in certain lakes.
Magnetic susceptibility of lake sediments
Authors: Thompson R. , Battarbee R. W. , O'Sullivan P. E. , Oldfield F.
Published: March 2010

Initial magnetic susceptibility in Flandrian sediments from Lough Neagh, N. Ireland, is shown to be a function of the detrital titanomagnetite of the sediment. Parallel susceptibility changes are synchronous from core to core and thus potentially valuable for core correlation especially in view of the rapid nondestructive techniques developed for measurement. Changing susceptibility in the lake sediments studied appears to be positively correlated with variations in the amount of inwashed inorganic allochthonous material present in the cores.
Stratified lake and oceanic brines: Salt movement and time limits of existence1
Authors: Toth David J. , Lerman Abraham
Published: March 2010

Pronounced salt concentration gradients in five antarctic, arctic, and Pacific coastal lakes an be accounted for by diffusional transport of salt out of the deeper saline water layers. The computed values of the mean salt diffusion coefficients, based on the ages of salinity stratification, agree to within an order of magnitude with molecular diffusivities for four out of five lakes. This agreement suggests that no major mixing events occurred in the water column during the late historical stages of the lakes. Upper limit time estimates for the removal of most of the salt from the saline bottom layers range from 5,000 to 35,000 years, depending on lake depth. Historical records of deepening of the Great Bitter Lake owing to dissolution of a salt layer on the bottom suggest that dissolution was a diffusion controlled process. For the saline brines in the Red Sea Deeps, an assumption that they are transient structures leads to the following estimates of the time to mixing with Red Sea water: 103–104 years, if mixing takes place by diffusional transport of salt between the heavier and lighter brines, and 104–105 years, if salt diffuses from the brines upward. The geologically short range of times suggests that the possible recycling of evaporative brines through the deeper ocean could not affect the ocean water salinity for any significant time interval.
Transuranics and other radionuclides in Bikini Lagoon: Concentration data retrieved from aged coral sections1
Authors: Noshkin V. E. , Wong K. M. , Eagle R. J. , Gatrousis C.
Published: March 2010

X‐radiography and autoradiography of thin vertical sections were used to estimate the growth rate of a specimen of Favites virens from Bikini Lagoon. Discrete bands of radioactivity were identifiable with specific nuclear test series. The coral growth rate of 8.0 mm year−1 determined by autoradiography is in good agreement with the rate of 8.1 ± 2.2 mm year−1 derived from the “seasonal” alternating light and dark bands on X‐radiographs. With these bands as growth rate indicators, the coral was sectioned into yearly increments and analyzed by low‐level, nondestructive gamma spectrometry, radiochemical techniques, and mass spectrometry to reconstruct the variations in the concentration of transuranics and other radionuclides in the marine environment at Bikini since 1954. From the concentration data retained in this indicator species, the exchange rate of radionuclides between the lagoon and the open ocean is computed to be longer than exchange rates based on physical circulation data. There is no constant ratio of plutonium isotopes in the coral growth sections, suggesting that the redistributions of the several plutonium isotopes in the environment may be governed by different biogeochemical processes. Increased levels of 210Po (210Pb) were found in test‐year growth sections, contradicting previous arguments that no 210Pb has resulted from weapons testing.
Chemically enhanced CO2 gas exchange in a eutrophic lake: A general model1
Authors: Emerson Steve
Published: March 2010

The exchange of carbon dioxide between the atmosphere and water is governed by the kinetics of diffusion and reaction in the interfacial boundary layer. Previous derivations of the equations describing this process are not always applicable to lakes. A general model, developed to explain the CO2 exchange rate in eutrophic Lake 227 of the Experimental Lakes Area, indicates that carbon dioxide invasion into this lake is five to ten times that predicted if there were no reaction. The model results conform with data from laboratory CO2 invasion experiments. The large chemical enchancement in Lake 227 is caused by a strong CO2 gradient resulting from an epilimnion depleted of carbon dioxide by eutrophication. These results indicate that calculations of the CO2 gas exchange rate, especially in eutrophic lakes, must consider the possibility of a relatively large enhancement factor.
Electrostatic collection of jet and film drops1
Authors: Blanchard Duncan C. , Syzdek Lawrence D.
Published: March 2010

Jet and film drops from bubbles bursting in the presence of an electric field will be charged by electrostatic induction. If the field is sufficiently high, the drops move rapidly upward under the influence of an electrical force to impact on any suitable collecting surface. Magnesium oxide‐coated glass slides make an excellent collector for determination of the size distribution of either jet or film drops. An agar plate collector can be used to collect all of the jet drops for bacterial analysis. Combining the two types of electrostatic collectors provides evidence that suggests that the enrichment of bacteria in jet drops is highest on the top or uppermost drop and decreases progressively to a minimum value for the last few jet drops to be ejected from the bubble.
Particle size distributions in a region of coastal upwelling analyzed by characteristic vectors1
Authors: Kitchen James C. , Menzies David , Pak Hasong , Ronald J. , Zaneveld V.
Published: March 2010

Particle size distributions (8–105‐µm diameter), chlorophyll a, and particulate carbon were measured off the Oregon coast during July 1973. The particle counts were transformed to volume concentration and then subjected to characteristic vector analysis. Ninety‐two percent of the variance was accounted for by linear combinations of the first two characteristic vectors. Two weighting factors define the proportions of the two characteristic vectors which will, when added to the mean volume concentration curve, approximate the actual data for each sample. Variations in the first weighting factor correspond well with variations in total volume. Changes in the second weighting factor indicate which segment of the size range contains the largest proportion of the particulate volume. Comparison with temperature and salinity data indicated that the near surface water with proportionately large volumes of particles less than 20 µm was warmer and less saline than the surface waters with large volumes between 20 and 50 µm. High correlation with particulate carbon and chlorophyll suggests that in both cases a large proportion of the particles is phytoplankton.
Test of Redfields model for oxygen‐nutrient relationships using regression analysis1
Authors: Alvarez‐Borrego Saul , Guthrie Donald , Culberson Charles H. , Park P. Kilho
Published: March 2010

Multiple regression analysis was applied to oxygen, phosphate, and nitrate data from stations in the Atlantic and Pacific Oceans. The 95% confidence intervals for ΔO2 : PO4 and ΔO2 : ΔNO3 ratios were consistent with Redfield’s model. Thus, the variation of O2–PO4 and O2–NO3 slopes with depth, latitude, and time is due to mixing between different water types with different preformed portions of oxygen, phosphate, and nitrate.
Oxygen‐nutrient relationships in the Pacific Ocean1
Authors: Alvarez‐Borrego Saul , Culberson Charles H. , Park P. Kilho
Published: March 2010

In the northeastern Pacific Ocean the oxygen‐phosphate and oxygen‐nitrate relationships vary systematically with latitude. The variation above the oxygen minimum zone is much more pronounced than below it. The slopes of these relationships in general increase with increasing latitude. In the entire water column these slopes vary with depth. A seasonal effect on the slopes of the oxygen‐phosphate and oxygen‐nitrate relationships, similar to that with decreasing latitude, is observed; the winter slopes are higher than the summer slopes. Potential temperature versus preformed phosphate diagrams were constructed for different stations in the Pacific and Indian Oceans to study their water masses.
Nitrogen fixation associated with the marine macroalga Codium fragile1
Authors: Head William D. , Carpenter Edward J.
Published: March 2010

Nitrogen fixation at rates of up to 7.3 µg N2 fixed g dry wt−1 h−1 is associated with the marine macroalga Codium fragile. A bacterium, identified as an Azotobacter, isolated from Codium, is capable of fixing atmospheric nitrogen in pure culture under aerobic conditions. Scanning electron micrographs showed dense populations of rod‐shaped bacteria, presumed to be Azotobacter, on the surface of Codium.

When Codium photosynthesis is decreased by light shading, N2 fixation drops proportionally, suggesting that fixation is coupled to the release of dissolved compounds by Codium. Addition of glucose to seawater increases N2 fixation, indicating that the agent of fixation is a heterotroph.

In a field survey, an inverse relationship was found between N2 fixation and the concentration of combined N compounds in seawater. At total available N (NO2−, NO3−, NH4+, urea) concentrations greater than 10 µg‐atoms liter−1, no fixation was associated with Codium. At Nobska Beach the total nitrogen input through N2 fixation in summer was 2.0 mg m−2 day−1 for water columns ranging between 1 and 3 m, and 0.47 in the 3–5‐m stratum.
Patterns of vertical distribution and migration of zooplankton at Ocean Station “P”1
Authors: Marlowe Christopher J. , Miller Charles B.
Published: March 2010

Stratified bongo net samples taken at depths between 0 and 500 m at Ocean Station “P” in the subarctic Pacific in early July 1971 have been analyzed to determine the vertical structure of the zooplankton community. Distributions for 99 categories of animals have been grouped by factor analysis into five basic patterns: surface dwellers, a bimodal subsurface pattern, and three patterns of deep‐dwelling forms with progressively deeper upper limits. Diurnal vertical migration was restricted to a very small fraction of the species present, primarily those previously described as strong migrators. The upward migration of some of these species stopped in the thermocline between 25 and 100 m. The minimum of biomass density found between 75 and 200 m by earlier workers was confirmed, and a similar minimum was found in the distribution of a number of species.
Respiration and the activity of the respiratory electron transport system in marine zooplankton1
Authors: King Frederick D. , Packard Theodore T.
Published: March 2010

Respiratory oxygen consumption and respiratory electron transport activity were measured for 15 species and several mixed populations of marine zooplankton. A high correlation (r > 0.97) was found that was only weakly affected by size of the animals and temperature. Regression equations are given for the calculation of respiration from electron transport activity.
Phosphorus excretion and the measurement of feeding and assimilation by zooplankton
Authors: Peters Robert Henry
Published: March 2010

A previously described model of the rate of P excretion by zooplankton shows that the excretion of recently ingested P can significantly affect estimates of assimilation but that short term measurements of ingestion are almost unchanged.
Methane oxidation in Lake Kivu (central Africa)1
Authors: Jannasch Holger W.
Published: March 2010

The rate of methane oxidation in Lake Kivu is estimated at 0.48 mmoles m−3 day−1 or 1.16 × 108 m3 yr−1 for the whole lake as measured in a layer of 15 m thickness above the oxic/anoxic interface. A total volume of 50 km3 of methane is calculated to be contained in the lake; the rates of methane production and of methane consumption appear to be of the same order of magnitude. The vertical diffusion of methane, and thereby its oxidation on reaching the oxic surface waters, is strongly restricted by the thermohaline stratification of the lake.
Some observations on the fluorometric determination of glucose in freshwater
Authors: Jones J. G. , Simon B. M.
Published: March 2010

The sensitivity of the fluorometric determination of glucose is occasionally severely reduced by quenching in profundal samples. The reproducibility of the method in such samples was investigated, as were the effects of dilution of mud samples and substrate concentration on the apparent glucose uptake rate. Observations on the disappearance of glucose from solution in the presence of mud showed that dilution of the mud could produce serious overestimates of the uptake rate. Analysis of the kinetics of uptake in undisturbed mud cores suggests that rough estimates of the kinetic parameters may be obtained for samples where the addition of radioactive tracers is undesirable.
A method for the spectrophotometric measurement of chlorophyll a and pheophytin a in benthic microalgae1
Authors: Tett Paul , Kelly Mahlon G. , Hornberger George M.
Published: March 2010

A method is described that allows the measurement of river periphyton chlorophyll a and pheophytin a both on rocks and in soft sediments. The method involves successive extractions directly from frozen samples with boiling methanol. Pigments are estimated by optical density measurements before and after acidification. Methanol is superior to acetone for the distinction of chlorophyll a and pheophytin a by this means.
Separation of total particulate carbon into inorganic and organic components1
Authors: Hirota Jed , Szyper James P.
Published: March 2010

A combination of particulate carbon analysis and a baking procedure to remove organic matter is proposed for separating total particulate carbon into inorganic and organic components. Changes in weight and carbonate‐carbon content were tested on powdered, anhydrous CaCO3 at 500° and 550°C and baking durations up to 7 h; the method was applied to field samples of particulate matter in seawater and microplankton net samples. The method is potentially useful for separating the carbon components, especially in coral reef environments or in calcium carbonate enriched sediments.
A comparison of two benthic infaunal samplers1
Authors: Dickinson John J. , Carey Andrew G.
Published: March 2010

The sampling efficiencies of a 0.1‐m2 Smith‐McIntyre grab and a deep‐sea, anchor‐box dredge were compared by determining estimates of faunal density and composition. The two samplers did not differ significantly in their description of the relative abundance of the fauna, but the grab sampler gave estimates of faunal density five times as large as the anchor‐box dredge.
Underwater observations of gelatinous zooplankton: Sampling problems, feeding biology, and behavior1
Authors: Hamner W. M. , Madin L. P. , Alldredge A. L. , Gilmer R. W. , Hamner P. P.
Published: March 2010

Observations by SCUBA divers on the distribution and biology of gelatinous zooplankton have stimulated speculations about the structure of tropical oceanic ecosystems. The gelatinous group represents one of four apparent strategies for survival in pelagic animals. Conventional plankton collection probably does not sample these organisms accurately due to their patchy distribution, fragility, and escape responses. Many gelatinous plankters filter feed using mucous structures; these mechanisms are important because of their efficiency in collecting particulate material, and because mucus is a source of organic aggregates in the sea. Such aggregates are often large, irregularly distributed, and of complex composition; these properties are rarely discerned by conventional sampling gear. The aggregates contribute considerable spatial heterogeneity to a seemingly homogeneous environment. An entire category of pelagic animals lives in association with these floating substrates. The diversity and trophic complexity of epipelagic plankton communities have been underestimated by previous investigators.
The rate of mucus production by corals and its assimilation by the coral reef copepod Acartia negligens1
Authors: Richman Sumner , Loya Y. , Sloboclkin Lawrence B.
Published: March 2010

The secretion of mucus by eight species of scleractinian corals was measured in situ at the Red Sea reef in Eilat, Israel. Selected coral heads were covered with plastic bags and the total organic matter collected after 24 h was determined. The rate of mucus production by massive forms was significantly greater than that by hemispherical or branched species, supporting the suggestion that the massive species use mucus secretion as a mechanism to prevent burial in heavy sedimentation areas on this reef.

Overall mucus production results in about 51 mg of particulate organic production m−3 day−1. Laboratory feeding experiments and assimilation measurements with Acartia negligens feeding on radioactive mucus indicate that the zooplankters can assimilate up to 50% of the organic matter of the mucus. Calorific determinations show this material to contain 5.2 ± 0.13 cal mg−1 ash‐free dry weight.
Detritus formation from eelgrass (Zostera marina L.): The relative effects of fragmentation, leaching, and decay
Authors: Harrison P. G. , Mann K. H.
Published: March 2010

In laboratory decomposition experiments dead eelgrass leaves lost a maximum of 35% of the original dry weight in 100 days at 20°C. Whole leaves lost 0.5% of their organic content per day whereas particles smaller than 1 mm lost 1% per day. Sterilization of leaves by dry heat or potassium cyanide showed that leaching accounted for 82% of the total loss of organic matter from predried material and 65% of the loss from undried material. Bacteria acting alone increased the nitrogen content of the detritus but only slowly degraded the leaf material. When protozoa were introduced, they grazed on the bacteria, maintained the bacterial population in an active metabolic state, and hastened the rate of decay. The C : N ratio of incubated detritus decreased from over 20 : 1 to as low as 11 : 1, indicating an increase in its potential food value. The overall slow rate of decomposition could enable the eelgrass detritus system to continue functioning during periodic short term fluctuations in eelgrass primary production by ensuring that a reservoir of slowly decomposing material is always present.
Burial of oscillaxanthin in the sediment of Lake Washington1
Authors: Griffiths Mary , Edmondson W. T.
Published: March 2010

The distribution of oscillaxanthin in new cores is different from that of cores taken earlier from the same regions. The vertical distribution of oscillaxanthin in six recent cores was qualitatively similar, showing low surface values and three maxima; quantitatively they varied, depending largely upon location, both in total oscillaxanthin (17.00 to 56.16 µg cm−2), and in the depth below which none was found (10.5 to 20.5 cm). Cores taken in 1967 had maxima in the surface centimeter and at mean depths of 3.5 cm and 7.5 cm, whereas 1972 cores had very little in the top 4 cm, and the three maxima had moved down to mean depths of 5.45 cm, 7.85 cm, and 10.35 cm. The present paucity of surface oscillaxanthin reflects the diminution of Oscillatoria in the lake resulting from the diversion of sewage.

On the basis of the changes in positions of the shallow maxima it appears that the top 4.95 cm of the sediment in the new cores was deposited in 5.5 years, between 1967 and 1972. However, owing to compaction of the underlying sediment only 2.85 cm was added to the total depth of sediment, giving a net annual accumulation rate of 5.2 mm.
Activity coefficients of bicarbonates and carbonates in seawater1
Authors: Pytkowicz R. M.
Published: March 2010

The total (stoichiometric) activity coefficients of bicarbonate and of carbonate ions were determined in seawater by a method that is independent of ion‐pairing models and used in conjunction with estimates of the coefficients of major cations to calculate the mean activity coefficients of bicarbonate and carbonate salts.
The in situ quantum efficiency of natural phytoplankton populations
Authors: Tyler John E.
Published: March 2010

The quantum efficiency of in situ photosynthesis for natural phytoplankton populations has been determined at various localities and depths in the ocean. Quantum efficiencies increased linearly with the logarithm of decreasing incident quanta at a rate varying with location.
Photosynthetic measurements in the central North Pacific: The dark loss of carbon in 24‐h incubations1
Authors: Eppley Richard W. , Sharp Jonathan H.
Published: March 2010

Half‐day incubations (noon‐sunset) and 24‐h incubations (noon–noon) with 14C‐labeled bicarbonate gave similar values for net primary production in the central gyre of the North Pacific (ca. 28°N, 155°W). Photosynthetic rates per light hour were nearly twice as high in 6‐h as in 24‐h incubations. The discrepancy seems to be due largely to dark respiration in the 24‐h incubations, and the data can be used to estimate dark loss of 14C.
Development of oxygen deficits in 14 southern Ontario lakes1
Authors: Lasenby David C.
Published: March 2010

Areal hypolimnetic oxygen deficits in 14 southern Ontario lakes developed linearly throughout summer in 13 of the lakes and decreased, usually linearly, as the upper limit of the hypolimnion was chosen at successively greater depths. Areal hypolimnetic oxygen deficit ranged from 0.006 to 0.041 mg cm−2 day−1; it was not correlated with average dry weight of seston in summer but was correlated with average Secchi depth during summer.
Differences in chemical composition between two species of Daphnia and some freshwater algae cultured in the laboratory1
Authors: Cowgill U. M. , Burns C. W.
Published: March 2010

Daphnia pulex Leydig, 1860, and Daphnia magna Straus, 1820, were cultured in spring water in glass aquaria and fed every day or two with a monoculture of Euglena gracilis Klebs and occasionally with a mixed algal culture containing mainly Chlorophyceae. Daphnia and algae were harvested weekly and accumulated over 3 months. Samples were analyzed by X‐ray emission and optical emission spectroscopy. Fifty‐three elements were detected in the spring water and 54 in the plankton. On a dry weight basis, both species of Daphnia contained higher concentrations of Na, Ca, Sc, La, Nd, Zr, Cl, Br, and Ni than the algae; the algae had accumulated, on the average, more K, Cu, Ag, Be, Mg, Zn, Hg, Al, Si, Sn, Pb, Ti, P, As, Mo, I, Fe, Mn, and Co than had the Daphnia. The concentrations of Ca and Cl were 2.1 and 3.2 times higher, respectively, in D. magna than in D. pulex.
Accumulation rate and turnover time of organic carbon in a salt marsh sediment1
Authors: Cammen Leon M.
Published: March 2010

Concentrations of organic carbon (excluding belowground plant material) decreased logarithmically with depth in the sediment of a Spartina alterniflora marsh near Drum Inlet, N.C. A similar decrease was measured in nearby areas of unvegetated dredge spoil and in dredge spoil planted with Spartina. Both spoil areas accumulated organic carhon, but the annual rate was higher where Spartina was present (range, 80.3–96.8 g C m−2). The organic carbon in the top 13 cm of the natural marsh sediment has a turnover time, based on this rate of accumulation, of 3.7 to 4.5 years.
A photochemical side reaction that interferes with the phenolhypochlorite assay for ammonia1,2
Authors: Gravitz Norman , Gleye Linda
Published: March 2010

Exposure to sunlight of the reaction mixture for the phenolhypochlorite assay for ammonia results in the formation of a compound that absorbs at 640 nm. This compound has been tentatively identified as indophenol, the same compound that is formed in the presence of ammonia. Protection of the reaction mixture from strong light results in low reagent blanks and ammonia standards that display a Beer’s law dependence on concentration.
Apparatus for the in situ concentration of trace metals from seawater
Authors: Davey Earl W. , Soper Albert E.
Published: March 2010

An apparatus designed to reduce trace metal contamination also functions to concentrate in situ particulate and dissolved Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn from seawater over integrated time intervals ranging from 1 day to 1 week.
A spectral light absorption meter for measurements in the sea
Authors: Hojerslev Niels
Published: March 2010

The light absorption coefficient of a medium such as seawater is an inherent optical property that can be determined in absolute values by means of the uncalibrated in situ light absorption meter described here. The method is based on the assumptions that the optical conditions remain steady within the measuring period, that the horizontal divergence of the vector equals zero, and that the natural fluorescent light energy within the visible part of the spectrum can be ignored. The light absorption meter measures simultaneously the sum and the difference of the scalar and vector irradiance.
A freely falling probe for small‐scale temperature gradients1
Authors: Caldwell Douglas R. , Wilcox Steve D. , Matsler Mark
Published: March 2010

A light, simple, and fairly inexpensive hand‐launched freely falling probe for measuring temperature microstructure was built. The circuitry operates under pressure in a Freon environment; low‐power integrated circuits are used as components. The probe is assembled from plastic pipe and fittings and recovered with monofilament fishing line. Standard XBTs are adapted for use as the data link. Noise levels of 2 × 10−5 °C cm−1 were achieved in signals recorded during casts in the ocean and on inland waters. Portions of the water column can be rapidly resampled. The device can be operated from any size vessel.
A piston corer for peat1
Authors: Redfield Alfred C.
Published: March 2010

The construction and operation of a corer capable of recovering uncontaminated and uncompressed samples of peat and other soft sediments from precisely predetermined depths is described.
Underwater observations of blue‐water plankton: Logistics, techniques, and safety procedures for divers at sea1
Authors: Hammer William M.
Published: March 2010

The results of more than 800 h spent in offshore dives in the eastern Florida Current near Bimini, Bahamas, in the Gulf of California, and in the Sargasso Sea to observe living, undisturbed plankton in the open sea suggest that the technique has much potential. The logistics of this type of research, particularly safety procedures, are reviewed in detail.
Herbivory as a factor in patterns of nutrient utilization in the sea1
Authors: Walsh John J.
Published: March 2010

A comparison of the horizontal nutrient gradients in coastal upwelling systems of the eastern boundary currents, in offshore divergences of high and low latitudes, and in the central gyres of the oceans suggests that changes in the dominant frequencies of variability of the physical habitat may define the importance of grazing stress as a constraint to nutrient utilization in the sea.