bluuebunny/crossref_metadata_2025_split huggingface dataset:
DISSOLVED OXYGEN IN SWEETWATER LAKE
Authors: Ramsey W. L. 
Published: March 2010

In Sweetwater Lake, near San Diego, California, vertical distribution of dissolved oxygen was observed to be highly stratified during the early summer months. With the lake at a maximum depth of about 32 ft, the lower 5 to 10 ft were devoid of oxygen by early July but mid‐depths and upper levels remained well‐oxygenated throughout the period of observation. The pattern of oxygen distribution in the lake appeared to reflect the prevailing summer circulation which consisted of rapid down‐wind movement at the surface with counter‐currents at mid‐depths and smaller circulation cells at lower depths. Rising summer temperatures caused an increase in the depth of the upper layer of water saturated or supersaturated with oxygen. The drop in solubility of oxygen due to heating of the surface layers of water was proportionally greater than the decrease in oxygen content, producing an increase in saturation values. Thermal stratification seemed to be sufficient, by reduced vertical mixing, to maintain the lake in a condition of oxygen‐rich epilimnion and oxygen‐depleted hypolimnion.Serial observations showed a diurnal cycle of rising oxygen content in the surface layers in late afternoon and evening, probably the results of the photosynthetic activity of the phytoplankton and the circulation of high oxygen water from the shallow end of the lake.Simultaneous sampling of the water at various depths for oxygen analysis and measurement of light transmission with a hydrophotometer produced no correlation between oxygen content and turbidity. Simultaneous measurement of sound velocity, attenuation and oxygen content also produced no conclusive results.
BENTHIC STUDIES IN BUZZARDS BAY II. THE MEIOFAUNA1
Authors: Wieser Wolfgang 
Published: March 2010

During the summer of 1957 a study of the small metazoans (meiofauna), based on a series of Phleger core samples, was undertaken at three stations in Buzzards Bay, Massachusetts. The number of animals ranged from 1.69 x 105 to 1.86 x 106/m2, the dry weights varied from approximately 100 to 600 mg/m2. The nematodes and kinorhynchs, which comprised between 89 and 99% of the total mieofauna, were studied in detail. The sandy localities (stations P and J) were characterized by a number of nematodes restricted to this habitat, particularly by three representatives of the genus Odontophora and by all representatives of the genus Leptonemella. The locality rich in fine deposits (station R) was characterized by the relative abundance of several nematodes, particularly of Terschellingia longicaudata, and the three kinorhynch species. It was possible to recognize an Odontophora‐Leptonemella community in the sandy habitats, and a Terschellingia longicaudata‐Trachydemus mainensis (kinorhynch) community in the silty habitat, the former being equivalent to the Ampelisca community, the latter to the Nucula proxima‐Nephthys incisa community described for the macrofauna in the same area. However, these “communities” can also be considered as two ecological groups of species, the former dependent on the presence of sand, the latter on that of fine deposits, which actually live side by side, forming an intricate meshwork of faunal combinations. Each combination is determined by the relative amounts of sand and fine deposits present.The uniformity of the nematode fauna within each station was greater than that between two different stations. Most important in determining the degree of faunal uniformity between paired samples is the similarity in their silt‐clay content. However, other mechanical factors also play a role.An analysis of the total species composition of the nematode fauna revealed that Terschellingia longicaudata was the most abundant species at station R, whereas at the stations P and J there were three or four equally dominant species. This is interpreted as indicating a splitting up of the sandy habitat into subhabitats. The simultaneous occurrence of closely related species in this environment further supports the conjecture.The distribution of “buccal types” amongst nematodes is correlated with the distribution of sediments.
OBSERVATIONS ON THE ECOLOGY OF THE SOFT CLAM, MYA AREN ARIA, IN A SALT POND1
Authors: Matthiessen George C. 
Published: March 2010

Observations were made on the ecology of the soft clam, Mya arenaria, in a salt water pond on Martha’s Vineyard, Mass., during the summer and fall of 1958. Primary consideration was given to the tolerance of this species to low and fluctuating salinities, the effect of salinity upon rate of growth, and possible correlation between growth rate and the nature and abundance of phytoplankton.Field observations supplemented by laboratory experimentation indicated that Mya longer than 2 mm can tolerate salinities less than 1‰ for at least 24 hrs and can withstand sudden salinity fluctuations of an order of 18‰. Tolerance of clams 2–5 mm in length to low salinities was found to be proportional to their size.Growth rate of clams living under different salinity conditions ranging in mean value from 3.5‰ to 14‰ was found to vary directly with salinity. The fact that the pumping rate of clams was observed to vary directly with salinity within the limits 0–31‰ is considered significant in this respect.Comparisons of growth rates with phytoplankton concentrations suggested that flagellates form an important source of nutrition for Mya and that diatoms may be of relatively little importance.
CARBAMINO CARBOXYLIC ACIDS IN PHOTOSYNTHESIS1
Authors: Smith James B. , Tatsumoto Mitsunobu , Hood Donald W. 
Published: March 2010

Cultures of Platymonas sp., Nitzschia closterium, and Porphyridium cruentum were found to utilize the carbamino complex of alanine or sea water concentrates in preference to inorganic forms of CO2 for photosynthesis. Evidence for this was obtained by inhibition of C14O2 uptake of photosynthesizing cells upon addition of the complex. Cell growth and oxygen evolution, however, continued to increase in a normal fashion. By labeling the complex in different portions of the molecule, it was shown that the plants were utilizing the N‐carboxylate group directly as a source of CO2 while utilization of other portions was not evidenced.Several other organic compounds were tested for response in the algae but only ammonium carbonate, known to contain small portions of ammonium carbamate, acted similarly.
THE ROLE OF ZOOPLANKTON IN THE NUTRITION OF SOME SCLERACTINIAN CORALS1
Authors: Johannes R. E. , Coles Stephen Lee , Kuenzel Nancy T. 
Published: March 2010

Over 15 days of continuous monitoring, the mean nocturnal concentration of drifting net zooplankton in a coral reef community on the Bermuda platform was 0.83 mg m−3. The mean respiration rate of reef‐building corals at the study site was calculated to be 6.4 g O2 day−1 m−2 of reef bottom. Using these data we show that the energy requirement of these corals was more than an order of magnitude greater than the energy they could obtain by capturing the sparse zooplankton in the surrounding waters.The question follows, why, if corals can exist in the absence of energetically significant quantities of zooplankton, do their elaborate anatomic modifications for catching zooplankton persist? Evidence indicates that corals cannot obtain their phosphorus requirements from solution. We therefore suggest that relatively small amounts of zooplankton may be important as a source of phosphorus and perhaps of other essential nutrients for both the coral and its algal symbionts.
THE SUBSURFACE BOUNDARY BETWEEN SUBARCTIC PACIFIC WATER AND PACIFIC EQUATORIAL, WATER IN THE TRANSITION ZONE OFF SOUTHERN CALIFORNIA
Authors: Blanton Jackson , Pattullo June G. 
Published: March 2010

Correlations of temperature with salinity and of temperature with oxygen demonstrated that in summer 1955, between southern California and Hawaii, there was an abrupt transition from Subarctic Pacific Water to a modified Pacific Equatorial at depths where thermosteric anomalies vary between 125 and 70 centiliters per metric ton. Between 125° and 140° W long the transition (a weak east‐west frontal zone) was well defined at about 26.5° N lat. East of 125° W, the front was not well defined.The oxygen minimum zones were found at different depths and at different thermosteric anomaly surfaces on either side of the transition. The oxygen minimum for Subarctic Pacific Water was about 200 m deeper than that of the water from the south. The two oxygen minimum zones were clearly separated by an “enriched” zone of dissolved oxygen which we take as evidence of vertical mixing. Vertical mixing was most strongly indicated nearshore in the vicinity of Point Conception.The boundary has a slope, with Subarctic Pacific Water overriding the southern water. The velocity difference across the boundary using the Margules‐Witte equation is 4 cm/sec cyclonically.
THE SECCHI DISK IN TURBID COASTAL WATERS1
Authors: Holmes Robert W. 
Published: March 2010

Measurements of Secchi disk depth are correlated with beam transmittance (B) in turbid coastal water. Both k (the irradiance attenuation coefficient) and α (the beam attenuance coefficient) can be estimated from the Secchi depth either on an empirical basis or by using the Duntley‐Preisendorfer equation of contrast reduction. Such estimates possess relatively large standard errors of estimate.The effects of the size of Secchi disk and viewing techniques are discussed. An estimate of contrast threshold of the human eye under field conditions has been obtained. A modification of the factor in the Poole and Atkins equation for estimating k from Secchi depth is suggested.
CYCLING OF ZINC‐65 BY COLIUMBIA RIVER PERIPHYTON IN A CLOSED LOTIC MICROCOSM1
Authors: Cushing Colbert E. , Rose Fred L. 
Published: March 2010

Studies of 65Zn cycling by periphyton were performed in a closed, lotic microcosm under varying light regimes, community state, initial ambient concentrations, and stable divalent cation concentrations.Uptake of 65Zn was considerable in continuous light, continuous darkness, a 12‐hr photoperiod, or by killed communities, indicating a dominant adsorptive uptake mechanism. Uptake of 65Zn was shown to be proportional to the initial ambient concentration of 65Zn, which decreased during the course of an experiment. Increasing the concentration of stable zinc or magnesium proportionately decreased the uptake of 65Zn, illustrating a competition for binding sites and supporting the adsorptive uptake theory.A discussion of the significance of this work to the reporting of concentration factors is presented. The similarity in function between the heterogeneous periphyton community and unialgal cultures or single species of plants is pointed out.
ULTRAVIOLET COM.BUSTION OF DISSOLVED ORGANIC NITROGEN COMPOUNDS IN LAKE WATERS1
Authors: Manny B. A. , Miller M. C. , Wetzel R. G. 
Published: March 2010

Ultraviolet combustion of lake waters combined with sensitive spectrophotometric NO3 + NO2‐N and NH4‐N analyses offers a 100‐fold increase in sensitivity over the micro‐Kjeldahl method for total dissolved organic nitrogen. The procedure permits quantification of two organic nitrogen fractions in lake waters based on the relative rate and amounts of labile NH4‐N and refractory NO3 + NO2‐N released. Combustions of water from six lakes under uniform conditions disclosed widely different amounts of the two fractions and increased amounts of the refractory fraction with increased depth in one lake.Duration of combustion, pH, and adequate oxygen affected ultraviolet combustions of freshwater samples and must be controlled to achieve uniform results. A recommended procedure for freshwaters consists of 1.5–3 hr of combustion with continuous oxygenation at pH 4.0 buffered with boric acid.Additions of organic carbon as glucose and glycine or tryptophane to standard solutions and natural lake samples demonstrated that the rate of nitrogen release and the final combustion product expression were a function of: 1) the molecular nature of the dissolved organic nitrogen compound (DONC), 2) the concentration of total dissolved organic carbon (TDOC), and 3) the inorganic salt concentration.Use of this procedure in comparing lakes of different trophic status should permit investigation of the role of DONC and its decomposition in primary production processes of lake ecosystems.
THE ANNUAL CYCLE IN QUANTITY AND COMPOSITION OF THE ZOOPLANKTON OF THE SARGASSO SEA OFF BERMUDA. I. THE UPPER 500 M1
Authors: Deevey Georgiana B. 
Published: March 2010

A year‐round quantitative and qualitative study has been made of the zooplankton collected by oblique 0–500‐m tows with a meter net of No. 2 and No. 8 mesh nylon at semimonthly intervals from 16 March 1961 to 7 April 1962 at station “S,” 24 km southeast of Bermuda in 3,200 m of water. Highest dry weights and displacement volumes were obtained in March 1961 and April 1962, but total numbers remained fairly high for most of the year, with a January–February minimum. Seasonal cycles of all the more numerous organisms are described.In the Sargasso Sea off Bermuda the annual cycle of zooplankton abundance is related to the degree of seasonal change; when the water column is mixed down to the permanent thermocline, greater quantities of phytoplankton and zooplankton are produced. In 1961– 1962 the mean standing crop of zooplankton was 70% of that recorded for Long Island Sound and Block Island Sound and 30% that of Georges Bank.Specific diversity in plankton populations was investigated by means of MacArthur’s information‐theory model and values for the coefficient of equitability obtained for the copepods and pteropods in the Sargasso Sea and for copepods in Long Island Sound, Block Island Sound, and Texas coastal waters. A seasonal cycle in equitability of plankton populations is apparently typical of waters where there is a sufficient degree of seasonal environmental change to produce unstable conditions or to permit changes in species composition during a year. The evenness of distribution of copepod species is more dependent on environmental stability than on number of species. The equitability of the copepod populations in the Sargasso Sea appears to be inversely correlated with productivity.
THE HORIZONTAL‐VERTICAL DISTRIBUTION HYPOTHESIS: LANGMUIR CIRCULATIONS AND DAPHNIA DISTRIBUTIONS1
Authors: Stavn Robert Hans 
Published: March 2010

The individual positions of a population of Daphnia magna Straus in a plastic chamber were recorded by infrared photography. The distribution of the Daphnia in the chamber was first observed during a 12‐hr light : 12‐hr dark regime and then during the photoperiod portion of the regime when spiral currents were introduced into the chamber. Observations during the 12L : 12D regime revealed a vertical migration tendency in the chamber while the horizontal position of the population oscillated from left to right.The currents introduced into the chamber were analogous to natural Langmuir spirals: horizontal components at the top and bottom, a downwelling at the left, and an upwelling at the right of the chamber. A slow current system, of velocity range 0.8–2.4 cm/sec, and a fast current system of velocity range 2.0–8.8 cm/sec were studied. During the photoperiod (light intensity above 70 ergs cm−2 sec−1), the Daphnia shifted to the left side of the chamber in the slow current system and to the right in the fast current system. The population shifts were caused by Daphnia’s steady swimming position heading into the current and counterbalancing a current velocity of 1–2 cm/sec by its swimming efforts. When the light intensity was below 70 ergs cm−2 sec−1, at the beginning and end of the photoperiods, the Daphnia populations drifted with the currents, unable to oppose them. The dorsal light reaction functions above a threshold light intensity of 70 ergs cm− 2 sec−1, so the current orientation must be made possible by visual detection of currents. Vertical displacements decreased in both experiments.From these experimental relations a model of active aggregation of Daphnia in Langmuir spirals has been constructed. The current velocity range within Langmuir spiral circulations will determine whether the Daphnia are aggregated in upwellings, downwellings, or in‐between portions of a spiral during a photoperiod. In darkness, passive aggregation tendencies described by earlier models will prevail. The presence of the dorsal light reaction in planktonic crustacea allows the generalization of the new model to account for at least the aggregation tendencies of planktonic crustacea.
THE RELATIVE IMPORTANCE OF NANNOPLANKTON AND NETPLANKTON AS PRIMARY PRODUCERS IN TROPICAL OCEANIC AND NERITIC PHYTOPLANKTON COMMUNITIES1
Authors: Malone Thomas C. 
Published: March 2010

Nannoplankton and netplankton primary productivity and standing crop were measured in a wide variety of neritic and oceanic environments in the eastern tropical Pacific and Caribbean region. Nannoplankters were the most important producers in all the environments studied, but netplankton productivity was significantly (P = 0.05) higher in neritic than in oceanic waters. Mean neritic netplankton–nannoplankton productivity and chlorophyll ratios were 0.50 ± 0.14 and 0.62 ± 0.22 respectively, significantly higher than those observed in oceanic waters.Relative levels of netplankton standing crop and productivity were not systematically related to corresponding levels of primary productivity and standing crop as a whole.The patterns of variation in the relative importance of netplankton and nannoplankton could be accounted for by the high netplankton growth rates and low grazing pressure indices observed in neritic as compared to oceanic waters.
NITROGEN FIXATION IN AN ESTUARINE ENVIRONMENT: THE WACCASASSA ON THE FLORIDA GULF COAST1
Authors: Brooks Ralph H. , Brezonik Patrick L. , Putnam Hugh D. , Keirn Michael A. 
Published: March 2010

Nitrogen fixation has been detected by the acetylene reduction method in the sediments of the Waccasassa estuary, a shallow embayment on the Florida Gulf Coast. Fixation rates in the range 1.6–15.0 ng C2H4/g sediment‐hr were found within the top 2–5‐cm stratum of sediments. Expressed in terms of equivalent nitrogen fixed, the range was 0.64–6.0 ng N/g‐hr. Much lower rates (0.03–0.40 ng C2H4/g‐hr) were found at greater depths in the sediment, and no fixation was observed in the flocculent unconsolidated 1–2 cm at the sediment surface.All evidence indicates that the reduction of acetylene to ethylene is a biological phenomenon, directly related to the activity of nitrogen‐fixing organisms in the sediments. Nitrogen‐free media produced growths of Gram‐positive spore‐forming rods from sediments under an N2 atmosphere. A pure culture similar to Clostridium sp. was isolated on nitrogen‐free media from Waccasassa sediments and was shown capable of nitrogen fixation by the acetylene reduction method.
NITROGEN FIXATION IN LAKE ERKEN1
Authors: Granhall Ulf , Lundgren Alf 
Published: March 2010

In situ fixation of molecular nitrogen was measured in 1970 in the pelagial of Lake Erken by the acetylene reduction technique every 2 weeks during a period of 5 months. The diurnal cycles and vertical distribution of algae were also investigated.Fixation was correlated with the presence of heterocystous blue‐green algae, especially Aphanizomenon, in the phytoplankton, and was light dependent, though appreciable dark fixation also occurred, owing to endogenous utilization of photosynthetic products formed during previous light periods. The annual contribution of nitrogen fixation in the pelagial was of the order 0.5 g N/m2. The highest values were obtained before mass development of Aphanizomenon and maximal primary production. The algae showed highest nitrogenase activity in the first period of algal development.Lake Erken is moderately eutrophic and unpolluted. The contribution of easily available combined nitrogen by pelagic nitrogen fixation increases the annual loading of combined nitrogen by 40% and must therefore be considered quite important.
GROWTH INTERACTIONS BETWEEN CHLAMYDOMONAS GLOBOSA SNOW AND CHLOROCOCCUM ELLIPSOIDEUM DEASON AND BOLD UNDER DIFFERENT EXPERIMENTAL CONDITIONS, WITH SPECIAL ATTENTION TO THE ROLE OF pH
Authors: Kroes H. W. 
Published: March 2010

The influence of Chlamydomonas globosa and Chlorococcum ellipsoideum on each other’s growth was studied with two different experimental techniques. The first is a newly developed filter culture method in which two separate cultures of different species are connected via a filtering system through which medium is exchanged while the cells themselves are kept separate. Under these circumstances Chlorococcum inhibits the growth of Chlamydomonas but not vice versa.In the second technique, traditional mixed cultures, Chlorococcum inhibits Chlamydomonas only in unbuffered medium. In medium buffered at pH 8.1 there is a slight stimulation of one or both species. The role of pII in the relation between the species seems therefore to be very important.
CONTRIBUTION BY SNOW TO THE NUTRIENT BUDGET OF SOME SMALL NORTHWEST ONTARIO LAKES
Authors: Barica Jan , Armstrong F. A. J. 
Published: March 2010

Nutrient elements accumulated in snow and ice on the surface of two oligotrophic northwest Ontario lakes during winter amounted to 264 mg particulate and 282 mg soluble C, 15.5 mg particulate and 43 mg soluble N, with 1.3 mg particulate and 2.7 mg soluble P per m2 of the lake area. From 61–92% of this material came from snowfall, and the remainder from the lake water by seepage through the ice and refreezing. These nutrients enter the lakes on thawing in spring and are then available for growth of phytoplankton. They represent a significant fraction of the nutrient budget of the lakes.Trace amounts of Ca, Mg, Na, K, Cl, and SO4 were also found in the snow‐ice cover, in quantities roughly a 10th of those in the lakes.The distribution of soluble and particulate matter in snow and ice varied somewhat from place to place and with time, and showed stratification.The processes of seepage, slush formation, and freezing to form layered ice and snow cover are described.
THE ANNUAL CYCLE IN QUANTITY AND COMPOSITION OF THE ZOOPLANKTON OF THE SARGASSO SEA OFF BERMUDA. II. THE SURFACE TO 2,000 m1
Authors: Deevey Georgiana B. , Brooks Albert L. 
Published: March 2010

Zooplankton samples were collected at station “S” (32° 10′ N, 64° 30′ W), 24 km SE of Bermuda in 3,200 m of water, at monthly intervals from July 1968 to June 1969, over four depth intervals from the surface to 2,000 m.In the upper 500 m highest numbers were found in October and April; between 500 and 1,000 m the highest numbers were present in July, March, and May; from 1,000 to 1,500 m the numbers were highest in August, January, and March. In the deepest waters sampled numbers were highest in July, October, March, and May.The displacement volumes for the upper 500 m showed a pronounced April maximum; the October maximum in numbers, consisting of small copepods, was not reflected in the volumes. Larger organisms were more common in the deeper waters. In going down the water column, volumes were approximately halved over each lower depth interval, but mean numbers decreased greatly between the upper waters and those of the 500–1,000‐m depth interval, indicating an increase in size of organisms between these two depth ranges.Crustacea increased in importance and in diversity below 500 m. Copepods comprised 70%. of the plankton of the upper 500 m and 85.2% in the deepest waters sampled. Pelagic ostracods were next in importance, but were relatively less numerous below 1,500 m. Highest numbers of calanoid genera and ostracod species were noted between 500 and 1,500 in. Euphausiids were most numerous between 1,500 and 2,000 m with a November maximum. Tunicates, coelenterates, chaetognaths, Foraminifera, pteropods, and various larval forms were most abundant in numbers and species in the upper waters, but occurred in small numbers below 500 m.