bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Distribution of Particulate Organic Carbon in the Oceans: Ecological Implications
Authors: Wangersky Peter J. 
Published: February 2007

AbstractDistribution of participate organic carbon (POC) in the oceans appears to be in the form of small “clouds” high in POC superimposed on lower background values typical of depth and water mass. The background values display an exponential decrease with depth. Samples taken at close intervals, both vertical and horizontal, suggest that the extent of these clouds in water below the photic zone must be less than a meter in any dimension. The concentration of POC in the clouds is of the same order as that found in surface waters. Feeding behaviour of the larger zooplankton may involve active searching for these patches; the organisms should be examined for evidences of mechanisms for finding patches. The maximum distance between patches, even in deeper water, must be of the order of a few tens of meters.
Automated Phytoplankton Analysis by a Pattern Recognition Method
Authors: Uhlmann D. , Schlimpeet O. , Uhlmann W. 
Published: February 2007

AbstractAn automated image processing and pattern recognition system was applied to the identification of the following genera exhibiting distinct differences in shape: Asterionella, Melosira, Fragilaria, Ceratium, Peridinium. The classification structure developed by a computer program was able to attribute all colonies or cells considered to the corresponding genus.
Limnological Studies on the River Tigris, Iraq. II. Seasonal Variations of Nutrients
Authors: Saad Massoud A. H. , Antoine Samir E. 
Published: February 2007

AbstractRegional and seasonal variations of nutrients in the 630 km stretch of the lower Tigris were studied and discussed. The lowest average values for nitrate and phosphate, found in July and October respectively, were correlated mainly with the high rates of uptake by phytoplankton. The lowest average concentration of silicate, recorded in July, can be related principally to the considerable increase in diatom density. Additional nutrients entered into the River Tigris in January through land runoff and in April with the flood waters. The average concentrations of nitrate and phosphate showed an inverse relationship. The average nitrate: nitrite ratio varied from 0.07 : 1 to 782.0 : 1 and the average nitrate : phosphate ratio ranged from 0.01 : 1 to 7.90 : 1.
Le traîneau suprabenthique MACER‐GIROQ : appareil amélioré pour l'échantillonnage quantitatif étagé de la petite faune nageuse an voisinage du fond The MACER‐GIROQ Suprabenthic Sled: An Improved Device for Quantitative Two‐level Sampling of the Small Swimming Fauna near the Bottom
Authors: Brunel P. , Besner M. , Messier D. , Poirier L. , Granger D. , Weinstein M. 
Published: February 2007

AbstractEnlarged versions of the MACER sled‐mounted suprabenthic sampler were tested, improved, calibrated and used extensively (598 tows) at depths of 10—384 m since 1968 in the Gulf and Estuary of the St. Lawrence. Two half‐metre zooplankton nets are mounted at 28—64 and 106—142 cm from the sea‐bed, on a steel chassis and toboggan plate. Each has a flow‐meter and 3 horizontal shutters which open via a lever upon contact with the sea floor. They close automatically, through springs and water pressure, whenever the sled leaves the bottom, ensuring uncontaminated suprabenthic samples. Although heavy (228 kg), the device is sturdy, used like a beam trawl, reliable, and collects very little sediment. It has been used to study micro‐stratification above bottom. Data on filtered water volumes, special problems encountered and future improvements are discussed.
Diel Patterns of Phytoplankton Productivity and Extracellular Release in Ultra‐Oligotrophic Lake Tahoe
Authors: Tilzer Max M. , Horne Alexander J. 
Published: February 2007

AbstractPhytoplankton in Lake Tahoe is dominated by diatoms and chrysophytes. High water transparency permits photosynthesis to a maximum depth of over 100 m. Average annual primary production rates in the entire trophogenic zone are 0.5–0.6 g C m−3 year−1.Nutrient concentrations and biomass parameters showed little diel variation. Photosynthesis in mixed water columns decreased in the afternoon. This decline can be attributed to inactivation of algae by overoptimal light during mid‐day hours. As the summer season progressed, algae became adapted to high light intensities and thus were less susceptible to light inhibition. Extracellular release by algae averaged 12.5 ± 7.4% of assimilated carbon without significant vertical differences. Damage of cells by light thus can be excluded. Respiratory losses overnight comprised at least 30% of the carbon assimilated during the preceding day. Integral photosynthesis showed a logarithmic relationship to incident light which can be used to predict daily production rates from mid‐day incubation with an error of well below 10%.
Niche Modification in Chaetognatha Infected with Larval Trematodes (Digenea)
Authors: Pearre Sifford 
Published: February 2007

AbstractInfection by larval trematode parasites caused sympatric chaetognath species to live nearer the surface than normal, hence to select more upper water prey than did non‐parasitized chaetognaths of the same species. This was associated with contagious distribution of parasites within the population.Trematode larvae appear as opaque objects in their almost transparent chaetognath hosts. Since they also induced their hosts to be larger and to live in better‐lit habitat than non‐parasitized ones, the parasites render their hosts more conspicuous and thus probably more susceptible to sight hunting fish predators. Available data from seasonal cycles of parasitism in chaetognaths confirms that trematode‐parasitized chaetognaths suffer higher mortality than normal, probably ascribable to predation. However, the size increase also may discourage predation by smaller, incorrect final host species.Localization of parasitism (which lowers individual reproductive potential). and predation in the same segment of the population should minimize loss of reproductive potential for the chaetognath population as a whole. This conservation of host resources can be considered primarily of benefit to the trematodes.Knowledge of parasite‐induced host modification should enable prediction of mode of parasite transmission, and vice‐versa. Contagious distribution of parasites in their host populations can help damp population cycling.
Hesionides riegerorum n. sp., a New Interstitial Freshwater Polychaete from the United States
Authors: Westheide Wilfried 
Published: February 2007

AbstractHesionides riegerorum n. sp. is a new freshwater polychaete species. It was found in considerable numbers in the interstitial habitat of sandy banks of the Chowan River in North Carolina, USA. There are no general differences in the organization and behavior compared to the marine species of this genus. The new species, however, is unequivocally distinguished from them by slight quantitative differences and more striking qualitative features. The localities not far from the coast point to an immigration path for this freshwater polychaete that has been shown also for most of the other marine interstitial immigrants: directly from sandy intertidal beaches along brackish estuaries into the limnopsammal.
Numerical Abundance and Biomass of Bacteria, Algae and Macrobenthos of a Large Northern River, the Athabasca
Authors: Barton David R. , Lock Maurice A. 
Published: February 2007

AbstractThe benthic flora and fauna of a large, turbid, northern river was sampled in autumn. Macroinvertebrate communities on bedrock resembled those of smaller streams but specialized Chironomidae larvae dominated sandy substrates. Bacterial densities on rocks were within the ranges reported from smaller streams. Benthic primary production is probably limited by high turbidity so that most of the energy available to benthic communites is probably allochthonous in origin.
Hydrologic and Total Phosphorus Budgets of A Small West Virginia Impoundment
Authors: Labaugh James W. 
Published: February 2007

AbstractHydrologic and total phosphorus budget data were obtained during a 24 month period for Spruce Knob Lake, Randolph County, West Virginia. Total phophorus retention was approximately 36% of input for both years despite differences in flushing rate. Based on total phosphorus and hydrologic data, Spruce Knob Lake is eutrophic. Predicted spring total phosphorus concentrations from the Dillon‐Rigler nutrient budget model were in close agreement with actual observed concentrations. Application of literature models predicting total phosphorus retention based on flushing rate to Spruce Knob Lake data resulted in close agreement with actual retention values. Models based on hydraulic load were inadequate when applied to Spruce Knob Lake. Relative phosphorus residence time values (lake total phosphorus/inflow total phosphorus). for both years indicated that the lake has a low sedimentation rate. Mass balance data confirmed this low rate of sedimentation.
Assimilation de composés organiques dissous dans le secteur antarctique de l'Ocean Indien.
Authors: Jacques Guy , Cahet Guy 
Published: February 2007

AbstractUptake of Dissolved Organic Compounds in the Antarctic Sector of the Indian OceanThe kinetic approach was used to determine the heterotrophic potential of the Indian Antarctic waters for three dissolved organic compouds: glucose, proline and glutamate. Variations with depth and latitude are discussed.
An Annotated List of the Stoneflies (Plecoptera). of the Soviet Far East
Authors: Levanidova I. M. , Zhiltzova L. A. 
Published: February 2007

AbstractThe 101 species of the order Plecoptera known to inhabit the Soviet Far East are listed, and the geographical distribution, as far as known, is provided for each. Information about the habitat preferences is also presented. The zoogeographical factors that contributed to the establishment of the present ranges are mentioned, and the relationships within some of the genera are discussed.
The Effect of Parrotfish (Scaridae) on Coral in Barbados, W. I
Authors: Frydl Paul 
Published: February 2007

AbstractAmong the five species of parrotfish studied, only largeSparisoma viride (and rarely large Scarus vetula) graze on live coral. Of the several species of corals grazed, Montastrea annularis is grazed most extensively, and variations in its form may be the result of grazing scars. Parrotfish feeding on algae at the bases of the corals Madracis mirabilis and Porites porites break off the corals. This attack causes recession of the stands of M. mirabilis at an average rate of 1 cm/month.
Analysis of Plankton Dynamics in a Southwestern U.S.A. Reservoir Using ATP Assays
Authors: Boswell J. T. , Perry W. B. , Stanford J. A. 
Published: February 2007

AbstractPlankton biomass in size segregated (i.e. 0.45–10 μm, 10–64 μm, 64–165 μm, and > 165 μm) samples was measured using ATP assays for two years in H. H. Moss Reservoir. The presence of variable numbers of microcrustacean zooplankton in the > 165 μ size class introduced significant, and perhaps inaccurate, variance into temporal dynamics of total ATP concentrations. As many as six physiochemical parameters, measured during 1975–76, were required to produce a significant multiple regression against ATP concentrations; a significant correlation between total ATP measured in the photic zone and surface temperature was observed. A large standing crop of nannoplankton (i.e. 0.45–10 μm) existed in the anaerobic and aphotic hypolimnion during summer stratification both years. This suggested that microbial heterotrophy was an especially important primary trophic event in the reservoir. Particulate (POC) and dissolved (DOC) organic carbon were measured in 1976–77. Organic carbon (POC + DOC) regressed significantly against ATP concentration in the 0.45–10 μm size class and microbial biomass (i.e. 0.45–165 μm) averaged 32 per cent of POC. When biomass was monitored over 24‐hour periods in the photic zone, significant changes were documented in various size classes, especially nannoplankton; but total microbial biomass remained relatively constant.
The Role of Predation in Causing Major Changes in the Limnology of a Hyper‐Eutrophic Lake
Authors: Leah R. T. , Moss Brian , Forrest D. E. 
Published: February 2007

AbstractAn experiment was carried out by separation of a shallow man‐made lake into two basins with an earth dam. Unintended leaks allowed extremely fertile river water to feed both basins so that nutrients were unlikely ever to have been limiting to phytoplankton populations. The two basins had greatly differing fish populations. In the basin in which these were low, a chain of events took place in which zooplankton grazing reduced phytoplankton growth sufficiently to allow establishment of aquatic macrophyte populations and an associated diverse benthic invertebrate community. In the basin to which fish had free access from the river, phytoplankton populations remained high, and no aquatic macrophyte community developed. The implications of these observations for shallow lake management are considered.
Influence of Hydrological Factors on the Seasonal Abundance of Phytoplankton in Kinjhar Lake, Pakistan
Authors: Nazneen Saiyida 
Published: February 2007

AbstractThe correlation of various hydrological factors with the distribution of phytoplankton and bacteria has been studied in Kinjhar Lake, situated 120 km north of Karachi. This lake is highly eutrophic, containing rich concentrations of nutrients, but the temporal distribution of phytoplankton was generally related to the variations of light and temperature. The effects of light and temperature are perhaps modified by nutrients, particularly when nitrogen and phosphorus are present in surprisingly low concentrations. The effect of mechanical disturbances in the artificial lake also has a significant effect on the growth of phytoplankton and indirectly on consumers, especially fishes.
Relationships Between Abundance of Insects and Standing Crop of Coarse Detritus in a Pennsylvania Stream
Authors: Miller Lee S. , Kovalak William P. 
Published: February 2007

AbstractRelationships between insect abundance and standing crop of coarse detritus, which was estimated both volumetrically and gravimetrically, were studied in a second‐order stream (Little Sugar Creek, Pennsylvania) between June 1977 and June 1978. For individual taxa, coefficients of determination (R2) for relationships between insect abundance and standing crop of detritus were significant (P≦0.05) in 39% (by volume) and 32% (by weight) of the cases. Deposit feeding collectors accounted for only 41% of the significant R2 values. For total fauna, R2 values were significant (P≦0.05) on 7 of the 11 dates (by volume) and on 8 of the 11 dates (by weight).
Investigations on the Problem of Scale Reduction and Sulphate Tolerance of West Anatolian Cyprinodonts (Pisces)
Authors: Grimm Helmut 
Published: February 2007

AbstractScale reduced populations of the Turkish species Aphanius anatoliae are usually found in biotopes containing magnesium and sodium sulphate. According to the hypothesis by Aksiray & Villwock (1962), there is a correlation between the adaptability to sulphate containing water and the scaly covering – a process which could be interpreted via pleiotropic gene effects. In laboratory experiments, the influence of sulphates on the ontogenetic development of the species A. anatoliae (5 populations), A. iberus, A. dispar, and A. mento was investigated. No difference in the salt tolerance of scale reduced fish and normally scaled fish was observed. In addition, the number of scales in the central lateral row do not support the hypothesis either. The scale reductions are discussed to be a consequence of processes of regressive evolution.
Benthic Invertebrates Associated with a Serpulid Polychaete Assemblage in a Temperate Estuary
Authors: Haines Judith Lynn , Maurer Don 
Published: February 2007

AbstractHydroides dianthus(Verrill), a serpulid polychaete which secretes calcareous tubes, provides microhabitats for a variety of benthic invertebrates in Delaware Bay. These microhabitats function as biologically generated refuges and physical heterogeneities for at least 54 species. Dominance was measured by the biological index value which yielded 12 taxa that comprised 90% by number of the serpulid assemblage. These taxa included seven polychaetes, two amphipods, Nematoda, Oligochaeta, and Harpacticoida. In addition to the refuges provided by the serpulids, it was concluded that this temperate serpulid assemblage was comparable in function but not scale to calcareous biogenic assemblages in lower latitudes.
Composition of Benthic Invertebrate Communities in Relation to Phytoplankton Populations in Five Subarctic Lakes
Authors: Moore James W. 
Published: February 2007

AbstractThe effects of algal food supply, temperature, water depth and lake size on the composition of benthic invertebrate communities were determined during 1978 und 1979 in 5 lakes in the Canadian subarctic. The lakes varied widely in physical conditions and trophic level, with peak algal densities ranging from 40 to 2100 mg/m3 during the summer and 10 to 750 mg/m3 in the winter. The correlation coefficients between the size of the populations of herbivorous chironomids (Chironomus riparius, Ch. plumosus, Ch. decorus, Tanytarsus xanthus) and the density of algae during the winter were highly significant and positive. There were also positive, albeit weak, correlations with the summer growth of algae, temperature, depth and lake size. In addition, the seasonal appearances of fourth instar larvae in the sediments were positively correlated with peaks in the abundance of phytoplankton. In contrast, algal food supplies probably had little impact on the density of oligotrophic indicator species (Heterotrissocladius oliveri, H. changi, Protanypus ramosus, Pontoporeia affinis) and were replaced in importance by temperature and water depth. Variations in the densities of the main oligochaete species (Uncinais uncinata, Arcteonais lomondi, Limnodrilus claparedeianus) and mollusc species (Valvata sincera helicoidea) could not be related to any of the factors that were measured. The diversity of the communities was probably limited by low temperatures, whereas food supply, lake depth and lake size had little impact on the fauna.
The Manna Effect: A Model of Phytoplankton Patchiness in a Regenerative System
Authors: Wangersky Peter J. , Wangersky Charles P. 
Published: February 2007

AbstractA Monte Carlo model for the growth of phytoplankton in a regenerative system has been constructed. This model assumes that nutrients are regenerated randomly in time and space at the scale which is important to the individual organisms. Under such a regime, organisms originally arrayed in a random fashion assume a patchy distribution within fifteen or twenty divisions, with some species becoming nonrandom in their distribution within five divisions. Other factors, physical or biological, may also induce or enhance patchiness, but normal regenerative processes in a nutrient‐limited system are sufficient in themselves to explain the phenomenon. Patchiness should be considered as the normal state for nonmotile organisms.
Signal Analysis of Irradiation, Temperature and Primary Production in a Small Artificial Pond: I. The Annual Signals
Authors: Lingeman Robert 
Published: February 2007

AbstractThis paper provides an example of some initial steps in signal analysis applied to a simple aquatic ecosystem in the form of a small artificial pond. Irradation, water temperature and dissolved oxygen concentration were continuously recorded over a two year period. Following the definition and discussion of several related parameters, an analysis procedure for trends and forced annual patterns was proposed and carried out. The annual pattern of photosynthetic fixation of solar energy is characterized by the annual level transfer efficiency, and for the periodic part of the process, by the transfer gain and phase shift. The possible role of temperature is briefly discussed.
Nitrogen Fixation During Blooms of Nodularia in Coastal Waters and Backwaters of the Arkona Sea (Baltic Sea) in 1974
Authors: Hübel Helmut , Hübel Marianne 
Published: February 2007

AbstractNitrogen fixation was investigated by means of the acetylene reduction method during the development of a water bloom of Nodularia in coastal waters of the Baltic Sea west of the island of Hiddensee and in backwaters showing different degrees of eutrophication. Depending on plankton density, the values found varied greatly. The maximum of nitrogen fixation values found in extremely dense water blooms under special conditions (Baltic Sea, 2250 μg N2/l · h; Kleiner Jasmunder Bodden, 374 μg N2/l · h) are up to 103 times higher than from other parts of the Baltic Sea or from inland waters. The average nitrogenase activity determined for coastal water populations of the Baltic Sea is 2.15 pg N2/heterocyst · h and that of the inmost backwaters 0.77 pg N2/heterocyst · h. The relationship between N2‐fixation and nutrient content in water is discussed.
Distribution, Abundance and Life Cycles of Oligochaeta from the Marine Hygropsammal with Special Reference to the Phallodrilinae (Tubificidae)
Authors: Pfannkuche Olaf 
Published: February 2007

AbstractTubificid and enchytraeid oligochaetes are common members of the interstitial fauna of sandy beaches. Their abundance dynamics, life cycles and distribution patterns were investigated at two beaches on the western Baltic Sea and at a North Sea beach (Isle of Sylt). Populations of 115,000 ind./m2 were found at protected Baltic beaches. Reproduction of the tubificids, Phallodrilus monospermathecus and Spiridion insigne takes place within a well defined breeding period once a year. The market horizontal and vertical distribution patterns of various tubificid and enchytraeid species are elucidated by preference reactions to several physiographic parameters, such as oxygen and water content of the sediment, and salinity.
Seasonal Changes in the Quantity and Nitrogen Content of Coarse Detritus in a Southern Ontario Stream
Authors: Wakefield Robert H. , Harrison Arthur D. , Kovalak William P. 
Published: February 2007

AbstractSeasonal changes in standing crop of coarse, benthic detritus at five locations across a second‐order stream were studied between May 1971 and May 1972. Standing crop near the banks varied seasonally with highest quantities in the autumn and winter, whereas near midstream seasonal changes in standing crop were negligible. Mean annual standing crop was 747 g/m2 (ash‐free dry weight) near the banks and 225 g/m2 (AFDW) at midstream. Deposition experiments showed that standing crops of detritus came to equilibrium in 2–3 days at midstream and in about one week near the banks. Nitrogen content of coarse detritus, which ranged between 0.65 and 3.51% (AFDW), did not vary seasonally but was significantly greater near the banks than at midstream.
Signal Analysis of Irradiation, Temperature and Primary Production in a Small Artificial Pond. II. The Residual Spectra
Authors: Lingeman Robert 
Published: February 2007

AbstractIrradiation, water temperature and dissolved oxygen of a small artificial pond were continuously recorded over a two year period. Following the elimination of previously estimated mean trends and forced annual patterns (LINGEMAN 1980) a spectral analysis procedure is proposed and executed for the residual signals of total diurnal irradiation, diel mean temperature and diurnal gross primary production. The residual power spectrum of diurnal irradiation was shown to be essentially the one of a white noise. Several higher frequencies were significantly present in both the signals of temperature and production. Some consideration is given to the cross correlation between the latter two parameters.