bluuebunny/crossref_metadata_2025_split huggingface dataset:
UPTAKE OF NEW AND REGENERATED FORMS OF NITROGEN IN PRIMARY PRODUCTIVITY1
Authors: Dugdale R. C. , Goering J. J. 
Published: March 2010

The use of 15N‐labeled compounds to obtain specific uptake rates for the various nitrogen sources available to the phytoplankton makes it possible to separate the fractions of primary productivity corresponding to new and regenerated nitrogen in the euphotic zone of the ocean. Measurements of nitrate uptake as a fraction of ammonia plus nitrate uptake have been obtained from the northwest Atlantic and the northeast Pacific oceans. Mean values range from 8.3 to 39.5%, the former being characteristic of subtropical regions and the latter of northern temperate regions or coastal and inland waters.Nitrogen fixation is also a source of new nitrogen. Rates of nitrogen fixation are found to be as high or higher than nitrate uptake, in some cases suggesting an important role for nitrogen‐fixing phytoplankton.The role of zooplankton in regenerating nitrogen as ammonia in the Sargasso Sea is examined theoretically. Probably only about 10% of the daily ammonia uptake by phytoplankton is contributed by the zooplankton living in the upper 100 m.
GROWTH OF MARINE BACTERIA AT LIMITING CONCENTRATIONS OF ORGANIC CARBON IN SEAWATER1
Authors: Jannasch Holger W. 
Published: March 2010

Growth responses of several species of heterotrophic marine bacteria to limiting concentrations of lactate, glycerol, and glucose in seawater were determined in a chemostat. In all cases, threshold concentrations of the limiting substrates were found below which the organisms were unable to grow. This phenomenon is explained on the basis of a positive feedback mechanism, which is abolished below a certain minimum population density. The resulting inhibitory effect on growth leaves a corresponding concentration of the limiting substrate unattacked.According to their growth parameters, two types of species could be distinguished, one adapted to the marine environment by its ability to grow at low substrate concentrations and one inactive in natural seawater but surviving.The implications of these results on the rates of microbial transformations and on the occurrence and concentrations of dissolved organic material in the sea are discussed.
CALCULATION OF CALCIUM ANOMALIES ON THE GREAT BAHAMA BANK FROM ALKALINITY AND CHLORINITY DATA1
Authors: Traganza Eugene D. , Szabo Barney J. 
Published: March 2010

Regional calcium anomalies can be calculated to ± 1% from alkalinity and chlorinity data. The “noncarbonate” calcium: chlorinity ratio is conserved. Deviations arise from random errors or processes other than CaCO3 precipitation, CO2 loss, or evaporation.Calcium concentrations have been calculated from the equation [Ca2+ (meq/liter) = Cl‰ + ½C.A.] with a precision of ± 0.01 meq/liter. In the field the value of K varies— from 0.479 to 0.506 (avg = 0.490)—suggesting that on the Great Bahama Bank, an accuracy of no more than ± 0.44 meq/liter or ca. 4% can be expected. Variation of the mean values of K may arise from systematic errors or from true variation of the ion: chlorinity ratios in different water masses.Dissolved calcium was determined using a high precision EDTA‐complexometric titration. The mean value for K, the “noncarbonate” : chlorinity ratio, was 0.481 ± 0.002 in July and 0.483 ± 0.003 in September 1964. The average : chlorinity weight ratios in July and September 1984 were 0.02113 at the bank edge, decreasing to 0.02033 with increased chlorinity.
TWO ANTARCTIC DESERT LAKES1
Authors: Goldman Charles R. , Mason David T. , Hobbie John E. 
Published: March 2010

The optical and biological properties of ice‐covered Lakes Vanda and Bonney, Antarctica, were observed during two austral summers. The lakes arc among the clearest known, with extinction coefficients as low as 0.031 for blue light in Lake Vanda and 0.069 for green light in Lake Bonney.Temperature and conductivity measurements in a shallow lake on Cape Evans, Antarctica, suggest a simple freezing‐out process as the possible origin of the monimolimnionic salt concentration in Lake Vanda.The lakes have a variety of living organisms but low standing crops and production rates. Many of the organisms are facultatively heterotrophic and may use dissolved organic substances for maintenance in the dark half of the year.
SOME OBSERVATIONS ON THE HATCHING OF TORTANUS DISCAUDATUS EGGS SUBJECTED TO LOW TEMPERATURES1
Authors: Johnson Martin W. 
Published: March 2010

Eggs of Tortanus discaudatus, a calanoid copepod, were sorted from the plankton at Friday Harbor, Washington, and set up in cultures subjected to temperatures ranging from 12.5C to −2C to observe the hatching rate and viability at low temperatures.At the higher temperatures, the eggs hatch in three to four days. Hatching goes on slowly at 0C, and of 20 eggs held at −2C, one hatched in 17 days and 53% of the remaining eggs hatched in five days when returned to 11.5C after an exposure of 30 days. Thus, the eggs were viable after at least one month at −2C.
STUDIES ON THE SEASONAL VARIATION OF THE SUSPENDED MATTER IN THE MENAI STRAITS. I. THE INORGANIC FRACTION
Authors: Buchan S. , Floodgate G. D. , Crisp D. J. 
Published: March 2010

The ash weight of material suspended in the waters of the Menai Straits was measured twice weekly between May 1962 and May 1963. The amount was much greater in winter than in summer and greater during spring than during neap tide periods. No differences could be detected between the ebb and flood periods within a single tidal cycle.The variations in ash weight correlated strongly with temperature but not with rainfall. There was a significant correlation between ash weight and the temperature‐related variables, σt and estimated freshwater runoff, but neither was significant after the effect of temperature was eliminated. The suspended burden was greater during periods of easterly winds, but no relationship could be established with wind velocity. The seasonal changes could not be attributed to changes in thermal instability or viscosity. The variations are thought to be caused by biological rather than by physical processes.
COMPARISON OF FILTERING RATES OF DAPHNIA ROSEA IN LAKE WATER AND IN SUSPENSIONS OF YEAST1
Authors: Burns Carolyn W. , Rigler F. H. 
Published: March 2010

Filtering rates of Daphnia rosea in natural lake water and in pure cultures of a yeast, Rhodotorula glutinis, were measured by adding 32P‐labeled yeast cells to the medium. The effects of the concentration of food, body length, and water temperature on filtering rates and feeding rates were examined. Results showed that filtering rate increased with increasing body length and increasing temperatures up to 20C. Above a concentration of 0.25 × 105 yeast cells/ml, filtering rate decreased with increasing cell concentration; below this concentration, filtering rate was maximal.From the results of these experiments, theoretical maximum filtering rates for the Daphnia population in Heart Lake over summer were predicted. A comparison of these theoretical rates and those measured in lake water in the laboratory revealed that from June to November the Daphnia were filtering at less than maximal rates.
STANDING CROP, VERTICAL DISTRIBUTION, AND MORPHOMETRICS OF AMMONIA BECCARII (LINNÉ)1
Authors: Brooks Albert L. 
Published: March 2010

Certain aspects of the ecology and the biology of the foraminifera Ammonia beccarii were investigated.The top 4 cm c replicate core samples from near the entrance to the West Passage of Narragansett Bay, Rhode Island, taken in 1963 were individually examined; presumed living and dead specimens were found at all four levels. Data on over 5,000 living and 7,500 dead specimens were collected from 283 samples.The use of a two‐stage sampling technique for determination of an optimum number of samples is described. The frequency distributions of the numbers of both presumed living and dead A. beccarii could be normalized successfully with a log (X + 1) transformation.At each of the four levels, the numbers of both living and dead individuals remained statistically constant, and the number of presumed living A. beccarii was the same in the three top 1‐cm levels but significantly greater there than at the fourth, while there were significantly fewer dead specimens in the first centimeter than in the third and fourth.
NUTRIENT LIMITATION IN THE SEA: DYNAMICS, IDENTIFICATION, AND SIGNIFICANCE1
Authors: Dugdale R. C. 
Published: March 2010

A mathematical model has been constructed to provide a theoretical framework for the investigation and discussion of nutrient limitation in the sea. The euphotic zone is divided into nutrient‐limited and light‐limited regions. For simplicity, the regeneration term is ignored, and a steady state is assumed. The uptake of major nutrients is assumed to follow the Michaelis‐Menton expression, and some data indicate that the assumption is probably correct. Also assuming a dominant phytoplankton population, with characteristic Michaelis‐Menton kinetic parameters, it is demonstrated that the size of the population, fractional growth rate, the rate of production, and the concentration of limiting nutrient are determined by the sum of the fractional loss rates for the phytoplankton. The role of micronutrient components of enzymes is developed theoretically using the effect of molybdenum on a nitrate‐limited system as an example.For the sea, the significance of nutrient limitation theory is primarily in the study of phytoplankton competition and succession. Applications to lakes are discussed, and it appears that the effects of micronutrient deficiencies are more likely to be observed there than in the sea.
PHOSPHORUS EXCRETION BY ZOOPLANKTON
Authors: Hargrave Barry T. , Geen Glen H. 
Published: March 2010

The excretion of dissolved inorganic and organic phosphorus by several species of marine crustaceans and a planktonic rotifer was measured under laboratory conditions. The rate of excretion decreased as bacterial activity and duration of experiments increased and was directly related to temperature and salinity. Excretion rates were higher in early evening than at other times of day.The daily phosphorus requirements of the phytoplankton, calculated from 14C measured rates of production and an assumed C : P ratio of 40 : 1, were compared with phosphorus released by zooplankton. The rates of excretion and the abundance of zooplankton were used to calculate an average daily addition of inorganic phosphorus to the photic zone. In Bras d’Or Lake, zooplankton released twice the average daily phytoplankton phosphorus requirement; in Morrison’s Pond, only one‐fifth was supplied by animal excretion. Microzooplankton excretion (not considered in this study) may explain the discrepancy between phytoplankton requirements and regeneration rate in Morrison’s Pond. Phosphorus supplied from the hypolimnion by eddy diffusion in Bras d’Or Lake was one‐tenth that regenerated by the zooplankton.
LIMNOLOGICAL EFFECTS OF ORGANIC EXTRACTS OF LITTER IN A SOUTHWESTERN IMPOUNDMENT
Authors: McConnell William J. 
Published: March 2010

Watershed litter in semiarid southeastern Arizona is relatively unleached, and the accumulation of a year or more is occasionally delivered to lakes within the first few days of the summer rainy season. Pena Blanca Lake received at least 750 g/m2 of oak litter during the summer of 1959. About 329 kg cal/m2 were delivered to the lake in oak litter extracts of which 26% were probably from carbohydrates, 54% from phenolic compounds, and 20% from unidentified compounds.Oak leaf extracts were experimentally effective as an energy source for microorganisms used as food by filter‐feeding organisms (Xenopus laevis) and snails. Efficiency of the extract‐microorganisms‐Xenopus and snail food chain was 3.28%.Based on an estimated ecological efficiency of 0.56% for the food chain: litter extract‐microorganisms‐zooplankton‐young Micropterus salmoides, Micropterus biomass production may have been increased 0.4 g/m2 by organic components in oak litter extracts contributed to Pena Blanca Lake in 1959. This increase represents 16.7% of the average annual fish harvest for 1959, 1960, and 1961.
OBSERVATIONS ON THE DECOMPOSITION OF A MARINE SEDIMENT
Authors: Seki H. , Skelding J. , Parsons T. R. 
Published: March 2010

The decomposition of organic material deposited in a small bay has been investigated. With a marine species of Pseudomonas as an assay organism, material deposited during summer and during winter were both actively decomposed. However, differences in the two types of sediment were apparent from the quantities of nutrients and carbohydrate available to the assay organism, as well as to the antibiotic activity of the two sediments.From calculations on the in situ nutrient and carbon budget for the sediment in the same area, it was determined that nitrogen was regenerated most rapidly, followed by phosphorus and carbon. The rate of sediment decomposition, determined as the ratio of the input of material to the steady‐state level in the sediment, is suggested as a basis for the biological comparison of nearshore marine sediments.
ZINC‐65 AND MANGANESE‐54 IN ALBACORE THUNNUS ALALUNGA FROM THE WEST COAST OF NORTH AMERICA
Authors: Pearcy William G. , Osterberg Charles L. 
Published: March 2010

Zinc‐65 and manganese‐54 were the dominant artificial radionuclides in the livers of albacore collected along the coast of North America from Washington to Baja California during the summers 1962–1966. The concentrations and specific activities of these radionuclides changed considerably during summer, indicating rapid responses to different radioecological conditions.Off Oregon and Washington 65Zn levels, as well as specific activities, in albacore increased markedly during summer months. Association of albacore with the effluent of the Columbia River accounted for this enhancement. The 65Zn concentrations of albacore from southern and Baja California were about 10% of those off Oregon and Washington with no seasonal trends evident. Highest radioactivities per gram and specific activities of 65Zn were found late in summer off Oregon. The 65Zn concentrations off southern Oregon at this time were as high as those off northern Oregon near the mouth of the Columbia River, probably because of the southward drift of plume waters coupled with the lag time for accumulation of 65Zn through several trophic levels. We have no evidence either for immigration of 65Zn‐tagged albacore into the southern California fishery or for immigration of southern albacore, with low 65Zn content, into the northern fishery during one season.Manganese‐54 enters the ocean primarily from fallout of nuclear weapons tests. Both the radioactivity and the specific activity of 54Mn in albacore off Oregon and Washington decreased during summer. Thus 54Mn appeared to be more available to albacore in offshore waters than in the nearshore waters. The levels of 54Mn in albacore were rather similar during the years of this study; this was unexpected since all the 54Mn presumably originated from 1961–1962 nuclear weapons tests.
MEASUREMENT OF DEOXYRIBONUCLEIC ACID IN THE OCEAN AND ITS ECOLOGICAL SIGNIFICANCE1
Authors: Sutcliffe William H. , Sharp Jonathan 
Published: March 2010

A method is described for the quantitative determination of deoxyribonucleic acid (DNA) by measurement of the fluorescence of the complex formed by incubating samples containing DNA with diaminobenzoic acid dihydrochloride. The sensitivity and range (from 0.2 to 40‐µg of DNA) of this method permit DNA determination on seawater samples of 1 liter or less from the euphotic zone and on 1 to 4 liters from deep samples. The concentration of DNA has been measured at various stations in the Atlantic and Pacific oceans, together with measurements on chlorophyll, zooplankton, and organic carbon and nitrogen of the particulate material. These data are discussed in relation to the possible use of DNA as a biomass indicator.The DNA content of laboratory cultured cells of Skeletonema costatum, Dunaliella tertiolecta, and Monochrysis lutheri have been determined relative to the cellular contents of organic carbon, nitrogen, and chlorophyll. When expressed as a percentage of the total cellular dry weight, the DNA contents of these three marine phytoplankton species were 0.43, 0.66, and 0.40%, respectively.
PROPERTIES OF THE YELLOW ORGANIC ACIDS OF NATURAL WATERS1
Authors: Ghassemi Masood , Christman R. F. 
Published: March 2010

Gel filtration profiles obtained from a variety of naturally colored waters indicate that color producing molecules are mostly in the apparent molecular weight range of 700–10,000 relative to dextrans. One fraction seems to have a molecular weight in excess of 50,000. The apparent size of the color molecules was found to be pH dependent, increasing as pH increases. Size increases are attributed to increased functional group ionization and a decrease in the adsorbability on Sephadex.The degree of association of color molecules with iron was also found to be pH dependent, being greater at both high and low pH than in the range of 7–8.
VERTICAL DISTRIBUTION AND ORGANIC MATTER PRODUCTION OF PHOTOSYNTHETIC SULFUR BACTERIA IN JAPANESE LAKES
Authors: Takahashi Masayuki , Ichimura Shun‐ei 
Published: March 2010

The role of photosynthetic sulfur bacteria as primary producers in stagnant lakes having hydrogen sulfide is described. Photosynthetic bacteria normally appear at the boundary layer of the oxidative and reductive zones, where H2S is present and the light intensity is lower than 10% of the surface value. The water of this layer was milky green or pink due to dense populations of Thiorhodaceae or Chlorobacteriaceae. The amount of photosynthetic bacterial biomass measured on a chlorophyll basis ranged from 100 to 828 mg/m3 for Chl‐650, 60.7 to 79.5 mg/m3 for Chl‐660, and 19.8 to 186 mg/m3 for BChl in the growing period from July to October.In the lakes studied, organic matter was produced by phytoplankton in the epilimnion and mainly by photosynthetic sulfur bacteria in the reducing zone. The organic matter synthesized by these bacteria ranged from 9 to 25% of the total annual production in lakes rich in H2S and from about 3 to 5% in lakes poor in it.
THE FATTY ACID COMPOSITION OF ARCTIC MARINE PHYTOPLANKTON AND ZOOPLANKTON WITH SPECIAL REFERENCE TO MINOR ACIDS1
Authors: Lewis R. W. 
Published: March 2010

Collections of phytoplankton and of one species of zooplankton, the amphipod Apherusa glacialis, were made from the same area of the Chukchi Sea off Barrow, Alaska. The collections were analyzed for fatty acids, including branched‐chain acids and positional isomers.The phytoplankton contained iso and anteiso odd‐numbered acids that have not previously been reported from diatoms. In other respects, the composition was similar to that of diatoms from the North Sea. The amphipods had a simpler fatty acid composition with smaller amounts of polyenoic and branched‐chain acids than the phytoplankton.
SEASONAL COMPOSITION OF TEMPERATE PLANKTON COMMUNITIES: FREE AMINO ACIDS1
Authors: Jeffries H. Perry 
Published: March 2010

In marine plankton, the patterns of seasonal succession and free amino acid composition reveal several features in common. Free amino acid levels are generally higher in summer than in winter communities: major changes occur during periods of community change in late spring and early winter. These levels also appear to be an index of physiological condition and productive capacity. The variations are quantitative in terms of concentration per unit tissue weight; relative compositions are the same in both the summer and the winter dominant copepods (Acartia tonsa and Acartia clausi).Factor analysis reveals an extremely high degree of intercorrelation within the free amino acid pools. The phytoplankton‐microzooplankton, consisting primarily of diatoms and larval crustaceans in varying proportions, has greater consistency of quantitative change (one amino acid in relation to all others) than does the zooplankton. Furthermore, the amino acid communality of an estuarine phytoplankton‐microzooplankton community is surprisingly high.
ZOOPLANKTON STANDING CROP IN THE ARCTIC BASIN1
Authors: Hopkins Thomas L. 
Published: March 2010

An estimate of zooplankton standing crop in the central Arctic Ocean was obtained from 118 closing‐net samples collected from Ice Islands T‐3 and ARLIS II. The T‐3 samples were taken from the anticyclonic gyre in the Amerasia Basin north of Alaska; the ARLIS II samples were collected from the Eurasia Basin north of Greenland.Copepods were the most important group, constituting over 80% of the biomass. The most important genus was Calanus, which averaged half the biomass in the upper 1,500 in. Below 1,500 m the relative importance of Calanus declined. Copepods were also the most numerous (90%) metazoan plankters, though they were outnumbered by small radiolarians in the upper 100 m from July to early September.There was some evidence of a summer (July–August) increase in biomass in 0–100‐m samples from T‐3 and an increase in ARLIS II 0–100‐m samples from March to January as ARLIS II drifted towards Greenland. Average biomass concentrations for the three principal water masses of the Arctic Ocean were 0.62 mg dry wt/m3 for the Arctic surface layer (0–200 m), 0.14 mg/m3 for the Atlantic layer (200–900 m), and 0.04 mg/m3 for the Arctic deep‐water mass (>900 m). Total zooplankton biomass in the central Arctic was estimated at 1–2 × 106 metric tons (dry weight). Calculations based on available primary production data suggest that photosynthesis alone cannot meet the metabolic demands of the biomass of zooplankton in the central Arctic Basin.
STUDIES ON THE DISTRIBUTION OF COBALT IN LAKES
Authors: Parker Michael , Hasler Arthur D. 
Published: March 2010

Cobalt‐57 was added to bottles of lake water to see whether there were any seasonal changes in the apportionment of cobalt between solution (filtrate) and seston after 24‐hr incubation or whether any differences in this distribution could be found between lakes.Several distinct patterns in the seasonal apportionment of 57Co between “solution” and seston were observed, but no explanation of the basic mechanism causing these changes is offered. In two of the lakes there was a statistically significant relation between certain detrital particles, rhizopods, and the per cent of introduced 57Co associated with solids.In general, direct biological uptake did not appear to be significant in removing 57Co from solution in Lake Mendota’s epilimnion. Photosynthetic activity was of little influence. Experiments with inhibitors and heated water also indicated that nonbiological processes were most important. Autoradiographs showed little radioactivity associated with algae.