bluuebunny/crossref_metadata_2025_split huggingface dataset:
BENTHIC AND LIMNETIC DISTRIBUTION OF THREE CHAOBORUS SPECIES IN A SOUTHERN MICHIGAN LAKE (DIPTERA, CHAOBORIDAE)
Authors: Roth James C. 
Published: March 2010

The benthic and limnetic distributions, and size‐frequency, of the overwintered larval populations of three Chaoborus species, C. punctipennis (Say), C. albatus Johnson, and C. flavicans (Meigen) in Frains Lake, Michigan, were investigated on three dates in May and June 1965. The three species made up 91, 3, and 6% of the Chaoborus fauna. Little overlap in total length was found between species. C. flavicans tended to be concentrated in deeper benthic zones during the day than C. punctipennis. C. albatus, but not the other two species, underwent an adlittoral benthic migration. All three species migrated into the limnetic zone at night, but none reached the surface. Most limnetic C. punctipennis larvae were found higher in the water column than C. flavicans larvae.The larvae of C. albatus were stunted, showed late growth, and may have been unable to avoid competition with larvae of the closely related C. punctipennis. Differences in distribution and morphology between C. flavicans and C. punctipennis, although slight, help to explain the apparent lack of competitive exclusion in this genus.
ESTIMATES OF THE LATENT AND SENSIBLE HEAT FLUX FOR THE CARIBBEAN SEA AND THE GULF OF MEXICO1
Authors: Hastenrath Stefan L. 
Published: March 2010

Monthly mean values of the latent and sensible heat flux at the sea‐air interface (Qe + Qs) are derived for the areas of the Caribbean Sea and the Gulf of Mexico, separately: 1) from the multiannual mean of the oceanic heat budget; 2) from the atmospheric energy budget, on the basis of the available radiosonde data for the entire year 1960; and 3) by the bulk‐aerodynamic method, using 1960 ship observations.The annual average of the latent and sensible heat transfer in the area of the Central American Seas is of the order of 270 ly/day. Making allowance for the propagation of errors and the different time periods used, the results of the three independent approaches are in fair agreement. The shortcomings inherent in all the procedures make various independent approaches desirable wherever possible.
SULFUR METABOLISM AND SEDIMENTARY ENVIRONMENT: LAKE MENDOTA, WISCONSIN
Authors: Nriagu Jerome O. 
Published: March 2010

The forms and distribution of sulfur in the black bottom muds of Lake Mendota have been determined and the data combined with available background information to gain understanding of sulfur metabolism in a freshwater sulfuretum and of the generic relationships among various forms of sulfur.The suite of sulfur compounds in the lake sediments is made up of sulfide dissolved in the interstitial water, acid‐volatile sulfide, elemental sulfur, organic sulfur, and sulfates. The dominant form of sulfur in the sludge is a black, amorphous, acid‐soluble substance believed to be hydrotroilite. No pyrite or marcasite was isolated from these bottom muds. Nearly 45% of the sulfur precipitated as sulfide is apparently derived from mineralization of organic matter with the remaining fraction coming from bacterial reduction of sulfates. The sulfur analyses coupled with other evidence suggest that prior to the change in sedimentation in Lake Mendota associated with human activity the lake had developed an oxygen deficiency intense enough to cause the reduction of sulfates to sulfides but was able to maintain its basin free of black muds by processes of self‐purification.
INFLUENCE OF HUMIC SUBSTANCES ON THE GROWTH OF MARINE PHYTOPLANKTON: DINOFLAGELLATES1
Authors: Prakash A. , Rashid M. A. 
Published: March 2010

Humic substances, in small amounts, exert a stimulatory effect on marine dinoflagellates that is reflected in increased yield, growth rate, and uptake. Humic acid was found to be more active than fulvic acid; in both cases the growth responses were dependent on concentration. Of the various fractions isolated, the low molecular weight fractions of humic acid produced the greatest growth response in unialgal cultures of dinoflagellates.The positive effect of humic substances on phytoplankton growth is, for the most part, independent of nutrient concentration and cannot be attributed entirely to chelation processes. It appears that growth enhancement in the presence of humic substances is linked with stimulation of algal cell metabolism. Because of their high concentrations in coastal waters, humic substances may thus be regarded as an ecologically significant entity influencing phytoplanktonic production.
THE NUTRITIONAL INADEQUACY OF CHLORELLA AND CHLAMYDOMONAS AS FOOD FOR DAPHNIA PULEX1
Authors: Taub Frieda B. , Dollar Alexander M. 
Published: March 2010

Daphnia pulex failed to reproduce normally when fed either Chlorella pyrenoidosa or Chlamydomonas reinhardtii cultured and suspended in defined inorganic media. Lifespan was shorter, ovulation was reduced, and a large percentage of ovulated eggs failed to complete embryonic development. The same algal culture suspended in “biologically conditioned water” supported a normal lifespan and ample but not maximal reproduction. The active factors are heat‐stable. Several organic compounds were tested to find a substitute for aquarium water. Calcium pantothenate (300 mg/liter) improved survival and reproduction significantly, but for only one generation; alanine, glucosamine, and carnatine were not significantly beneficial. CaC12 improved survival and reproduction of two succeeding generations. Despite increases in the amount of calcium added, Daphnia cultures could not be maintained indefinitely on Chlamydomonas suspended in a defined salt solution.The algae appear to be deficient in meeting the nutritional requirements of Daphnia pulex, especially with respect to reproduction. Their proper utilization seems to depend on factors supplied by other organisms, probably bacteria, and probably provided in the water from natural sources used in most experiments.
POPULATION STUDIES OF FOUR SPECIES OF MOLLUSCS IN THE MADISON RIVER, YELLOWSTONE NATIONAL PARK1
Authors: Gillespie D. M. 
Published: March 2010

Population statistics were calculated for natural populations of Physa gyrina, Gyraulus deflectus, Valvata humeralis, and Pisidium compressum.Total net production calculated for model populations was within 10% of the value calculated graphically. Data showed a generally good fit to the model curve. The average of the two methods of determining total annual net production of the gastropods was 5.150 g/m2. Assuming an efficiency of 0.25, total gastropod assimilation was approximately 10% of the annual net primary production. Growth rates apparently were not limited by food supply. Mortality rates were highest in spring and summer and lowest in winter with the principal causes predation and loss during high water. Reproductive periods of Physa, Gyraulus, and Pisidium extended from spring to fall; Valvata reproduction was largely limited to August.
MEASUREMENT AND ANALYSIS OF THE ANNUAL HEAT BUDGET FOR THE SEDIMENTS IN TWO WISCONSIN LAKES1
Authors: Likens Gene E. , Johnson Noye M. 
Published: March 2010

Temperature was measured in the water, bottom sediments, and bog surrounding Stewart’s Dark Lake and Tub Lake, Wisconsin, five times during 1965–1966. A thermal probe was used to penetrate to depths to 8 m into the bottom.In the deepest water of Stewart’s Dark Lake, with no seasonal temperature fluctuation, a steady‐state thermal gradient (0.20°C/m) was observed in the bottom sediments. Thermal conductivity of these gelatinous sediments was measured at 1.10 × 10−3 cal cm/cm2 sec°C; thus prescribing a steady‐state heat flow of 2.1 × 10−6 cal/cm2 sec or 66 cal/cm2 year.The pattern of isotherms within the bottom sediments and bog demonstrates the importance of solar radiation and the effects of absorption and circulation within these lakes. Seasonal changes in isotherm patterns are similar for both lakes. Seasonal temperature fluctuations are largely damped at depths below 4 m in the surrounding bogs. There is a negative (into the sediments) steady‐state thermal gradient associated with the shoreline, but the gradient becomes positive lakeward and landward. Thus, with respect to mean sediment temperatures, each lake is surrounded by a relatively warm rim.The annual heat budget of the sediments at the shoreline in Tub Lake was 3,670 cal/cm2; at a water depth of 8 m, it was 70 cal/cm2. The mean annual budget for the entire sediments of Stewart’s Dark Lake was 730 cal/cm2 and for Tub Lake was 970 cal/cm2. These values represent about 10 and 12%, respectively, of the total annual heat budgets for the water in each lake. The heat budget of the sediments is dependent on the amplitude of temperature variations of the overlying water and the thermal properties of the sediment.
STUDIES OF NITRATE REDUCTASE IN MARINE PHYTOPLANKTON1
Authors: Eppley R. W. , Coatsworth J. L. , Solórzano Lucia 
Published: March 2010

Certain marine phytoplankton contain the enzyme nitrate reductase when growing on nitrate, but only low levels of enzyme were found during growth with ammonium or when the nitrogen source was depleted. Netted samples of oceanic phytoplankton contained the enzyme when taken from waters with nitrate concentrations 2–10 µm. Ammonium was assimilated in preference to nitrate in phytoplankton cultures supplied with both forms of nitrogen at 5–15 µm. Enzyme synthesis and nitrate use began when ammonium was depleted to 0.5–1.0 µm.Nitrate reductase assay of phytoplankton samples is a useful tool in that a positive result indicates utilization of nitrate and a negative one implies growth on ammonium, nitrogen depletion, or, improbably, growth with other N‐sources such as nitrite, urea, or amino acids. The enzyme assay seems especially useful for studying the timecourse of phytoplankton blooms because it provides a sensitive measure of the initiation and cessation of nitrate assimilation.
OXYGEN CONSUMPTION OF EUPHAUSIA PACIFICA: THE LACK OF A DIEL RHYTHM OR LIGHT‐DARK EFFECT, WITH A COMPARISON OF EXPERIMENTAL TECHNIQUES1
Authors: Pearcy William G. , Theilacker Gail H. , Lasker Reuben 
Published: March 2010

We found no evidence for diel rhythms in the respiration of individual Euphausia pacifica during long‐term (11–32 hr) Warburg manometric experiments. Changes from light (1.2 × 102 µw cm−2) to dark (<1.8 × 10−5 µw cm−2) also had no appreciable effect on oxygen consumption of most of these euphausiids. Respiratory rates often decreased with time regardless of light conditions, but 2 of 20 animals respired consistently more in the dark than the light.Larger animals consumed less oxygen per unit weight than smaller ones. This factor contributed to differences between mean oxygen consumption rates of separate experiments. Although we obtained higher rates from the Winkler than the manometric method, the differences were not significant. The average rate (1.34 µl O2 mg−1 hr−1) from all our experiments (79 animals) was intermediate in the range of values reported in the literature.
OCEANIC HEAT CONTENT OFF OREGON: ITS VARIATIONS AND THEIR CAUSES1
Authors: Pattullo June G. , Burt Wayne V. , Kulm Sally A. 
Published: March 2010

Heat content, surface to 100 m, was computed for oceanographic stations within 165 nautical miles (305 km) of the Oregon coast. Mean content, 1962 through 1965, was 100 kg cal cm−2, with a root mean square deviation of 13 kg cal cm−2. The principal fluctuation around the mean was seasonal; the seasonal range among monthly mean values was twice as large offshore, beyond 100 miles (185 km) from the coast (35 kg cal cm−2) as the range inshore, within 65 miles (120 km) of shore (15 kg cal cm−2). The cause of the seasonal variation offshore was local heating, but advection was important inshore. Observed ranges in heat storage inshore were only a third as large as expected from the computed local heating. The results are consistent with inshore currents from the south in winter and coastal upwelling associated with offshore transport of water and heat in summer.For data off Newport, the sum of squares was partitioned by a hierarchal scheme. This revealed that inshore the seasonal regime was not dominant; fluctuations of long and short periods and geographical variations were also appreciable. It is suggested that future sampling in the inshore region be more intensive, with smaller intervals in both distance and time. It is also apparent that long records (tens of years) are needed both inshore and offshore if we wish to describe the major fluctuations of heat content, since long‐period deviations from the average seasonal cycle are indicated.
OSCILLAXANTHIN IN THE SEDIMENT OF LAKE WASHINGTON1
Authors: Griffiths Mary , Perrott Pamela S. , Edmondson W. T. 
Published: March 2010

Oscillaxanthin was determined quantitatively in portions of five cores cut in slices 1 cm thick. The distribution varied with depth in a manner qualitatively consistent in all cores, although there were quantitative differences. The pigment was undetectable below 9 cm in two cores, below 8 in another, and below 13 in the remaining two. The amount of pigment per unit dry weight of sediment was highest at the surface and had two subsurface maxima, at 4 cm for the shallow maximum, with a deep maximum at 7 cm for three cores, 8 cm for the fourth, and 9 cm for the fifth. The total accumulated pigment under unit area of bottom mud varied from 27.10 to 6.66 µg/cm2. To some extent these differences also relate to accumulation of organic matter and to other pigments. The oscillaxanthin‐producing algae evidently are somewhat differently distributed during sedimentation, for the differences are not related to differences in distribution of the plankton.The vertical distribution of oscillaxanthin within the sediments is considered in relation to the recent history of sewage enrichment of the lake. Oscillaxanthin is known to be produced by Oscillatoria rubescens and O. agardhii, both of which have occurred in abundance in Lake Washington since 1955 when O. rubescens was observed for the first time, in a relatively dense population. Oscillatoria agardhii occurred in small quantities in 1950. Cultured Anabaena circinalis, Microcystis aeruginosa, and Aphanizomenon flos‐aquae had negligible amounts of oscillaxanthin.On the basis of available evidence about sedimentation rates, oscillaxanthin must have been produced in the lake before the appearance of O. rubescens in 1955 and also before 1950. The first appearance of oscillaxanthin probably came early in the period of sewage enrichment that led to the recent diversion of sewage from Lake Washington. The reasons for the two maxima in concentration are not known. The changes apparently cannot be attributed to destruction of pigment or dilution with other components of sediment in varying amounts over the years and therefore seem to reflect changes in the production of Oscillatoria.
BLUE‐GREEN ALGAE AND CARBONATES—SCHIZOTHRIX CALCICOLA AND ALGAL STROMATOLITES FROM BERMUDA1
Authors: Sharp Jonathan H. 
Published: March 2010

Algal stromatolites (laminated sedimentary structures) have been studied in the process of formation in subtidal areas of Bermuda. The primary organism responsible for forming these structures is the blue‐green alga, Schizothrix calcicola. Laboratory studies of the formation of nonlaminated algal mats by unialgal cultures of S. calcicola showed that this species could bind sediment particles. The roles of S. calcicola and a secondary species, Oscillatoria submembranacea, in stromatolite formation have been examined.Since S. calcicola exists planktonically, it can be cultured from water samples. These cultures, and the presence of this species on various substrates in subtidal, intertidal, and supratidal areas indicate its wide distribution in Bermuda inshore waters.The distribution of S. calcicola and other filamentous cyanophytes, as well as consideration of physical factors of the subtidal environments, indicates that the latter probably control distribution of the Bermudian algal stromatolites.Reports of developing algal stromatolites from intertidal areas in other parts of the world indicate that S. calcicola is of major, if not primary, importance in the formation of stromatolites everywhere.
SOME EFFECTS OF LAKE RENEWAL ON PHYTOPLANKTON PRODUCTIVITY AND SPECIES COMPOSITION1
Authors: Dickman Mike 
Published: March 2010

Primary production in Marion Lake is inversely related to the rate at which water enters the lake when light intensity is corrected to a standard level. Increased flushing rates reduce the phytoplankton standing crop thereby lowering the total primary productivity in the lake. Thus seasonal variations in rainfall in southwestern British Columbia exert an appreciable influence on the annual productivity pattern of the lake’s phytoplankton.Lake water artificially enclosed within small areas of the lake produced algal blooms while phytoplankton standing crop in the rest of the lake remained low. Nannoplankton appear to have a selective advantage over larger, more slowly reproducing forms in Marion Lake. The production: biomass ratio for lake phytoplankton was used as an indication of the general type of limiting factor affecting the instantaneous rate of productivity in the lake.
THE FEEDING OF CALANUS HELGOLANDICUS ON SYNCHRONOUSLY GROWING POPULATIONS OF THE MARINE DIATOM DITYLUM BRIGHTWELLII1
Authors: Richman Sumner , Rogers Jane N. 
Published: March 2010

The filtering rates of Calanus helgolandicus were measured on synchronously growing populations of the diatom Ditylum brightwellii, by following changes in cell numbers and also by measuring the ingestion of 14C labeled cells at selected intervals during 2‐day periods. The growth of the diatoms was adjusted to be one cell division per day by selecting appropriate photoperiods and light intensities. When the alga was synchronized, cell division took place in the dark.Filtering rates were calculated separately for animals grazing on single cells and on “paired” daughter cells (before separation after division). The volume of paired cells was 1.5 times that of the singles. There was no significant difference in the filtering of single cells in the light or dark part of the cycle. Filtering on paired cells was significantly higher in the dark or at those times when high percentages of pairs were present. Between 0 and 20% pairs, the animals filtered at a constant rate of 50 ml copepod−1 day−1. Above 40% pairs, there was a maximum filtering rate of approximately 170 ml copepod−1 day−1. Between 20–40% pairs, the filtering rate increased proportionally to the percentage of pairs, and ingestion of paired cells increased exponentially in relation to their concentration.It is suggested that C. helgolandicus actively hunted and selected the paired cells and passively filtered the singles. In addition, the data support the idea that there is no innate diurnal feeding rhythm in these copepods.
COLORADO SEMIDRAINAGE MOUNTAIN LAKES1
Authors: Pennak Robert W. 
Published: March 2010

A distinctive semidrainage lake type is common at midmountain elevations in Colorado. Such lakes are similar in their small size, shallow depth, lack cf an outlet, high nitrate content, high organic content, and high water color.“Indicator species” are Rana pipiens, neotenic Ambystoma tigrinum, Gammarus limnaeus, an association of three leeches (Nephelopsis obscura, Glossiphonia complanata, and Helobdella stagnalis), and Nuphar polysepalum. Usually 8 to 14 species of rooted aquatics are present by late summer. Sponges arc abundant, fish are absent, and plankton is sparse.Evidence is presented to show that semidrainage lakes are limnoseres.
FAYETTEVILLE GREEN LAKE, NEW YORK. II. PRECIPITATION AND SEDIMENTATION OF CALCITE IN A MEROMICTIC LAKE WITH LAMINATED SEDIMENTS1
Authors: Brunskill G. J. 
Published: March 2010

The activities of calcium and carbonate in Fayetteville Green Lake were estimated from detailed seasonal measurements of pH, calcium, and titration alkalinity. By comparison of observed ion activity products (IAP) for Ca2+ and CO32− with the calcite equilibrium activity product (Kcq), the water column was found to be supersaturated throughout the year. In the surface waters of the mixolimnion, the ratio IAP: Keq increased from 2 to 4 in winter to 6 to 8 during late May through October.Precipitation of calcite was confirmed by collection of crystals in the water column by filtration, identification by X‐ray diffraction, and quantitative measurement by a gas chromatographic technique. Maximal crystal loads of 35 g CaCO3 m−2 in the water column occurred in June and July (1965–1967), while calcite loads in fall, winter, and early spring were reduced by an order of magnitude. From isopleths of suspended calcite, settling rates of 2–4 in day−1 were estimated for spring, which was close to values predicted from Stokes’ Law.About 90% of the total sedimentation occurred from June through October, and 80% of this mass was calcite. The laminae occurring in monimolimnetic sediments were regarded as annual couplets resulting from seasonal sedimentation of calcite, with deposition of organic matter throughout the year. The sedimentation rate derived from sediment trap data was 300 g dry matter m−2 yr−1. From the chemical composition of these samples, sedimentation rates were derived for CaCO3, acid insoluble organic carbon, acid insoluble nitrogen, and total nitrogen, sulfur, phosphorus, silicon, and iron.
PLANKTONIC FORAMINIFERA: DIFFERENTIAL PRODUCTION AND EXPATRIATION OFF BAJA CALIFORNIA1
Authors: Berger Wolfgang H. 
Published: March 2010

The species composition, living: dead ratios, morphology, and size distribution of planktonic foraminifera were studied in 54 depth‐controlled tow samples using a 333‐µ net (0– 3,000 m) from northwest of Guadalupe Island, Baja California. Paired sampling and replicate tows permitted the determination of confidence limits on concentration and percentage estimates.Average concentrations of living foraminifera range from about 1/m3 in shallow water to less than 1/1,000 m3 at depth. Concentrations of empty shells are between 3 to 10/1,000 m3 throughout. The depth of equal standing stock for live and empty individuals is between 5,000 and 10,000 in. The minimum replacement time for the living populations corresponds to the settling time through this column and is between 5 and 40 days. The apparent replacement times vary considerably between species and between sizes within species.The living assemblage consists of a mixture of northern, central, and southern species dominated by northern ones. Central water species are relatively abundant immediately below the surface water. The southern element has a maximum at about 1,000‐m depth. This distribution is in agreement with physical measurements, suggesting shallow entrainment of central water into the California Current and indicating a countercurrent at depth. It is suggested that the fauna contained in the oxygen‐poor intermediate water is expatriated and that its great proportion of specimens with small terminal chambers (“kummerforms”) is due to unfavorable living conditions during submergence.The notion that kummerform development indicates termination or slowing of growth is supported by a trend toward increase of kummerform proportions in living populations in large shell sizes and at subsurface depths and by the relatively high empty shell output of kummerforms. Oceanic stability of past ages may be recognized in fossil foraminiferal deposits if oceanic mixing enhances kummerform development and if the effects of differential preservation can be accounted for.