bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nutrient and Sediment Retention in a Temperate Marsh Ecosystem
Authors: Maccrimmon Hugh R. 
Published: February 2007

AbstractThe Wye marsh, an undeveloped wetland of 639.9 ha, serves as a receiving water for a 19,600 ha agricultural watershed before discharging into the Great Lakes. Seasonal and diel changes in limnological variables, most notably nitrogen, phosphorus, silica and turbidity, have been examined in the Wye river, marsh and discharge waters over an 11‐month period and related to the composition of marsh sediments. Retention rates of the marsh ecosystem for incoming nutrients and suspended solids have been estimated by calculations of mean monthly inflow to outflow ratios using the levels of these factors in the Wye River and the marsh discharge. Calculated mean monthly retention rates of the marsh for incoming nutrients is estimated at no less than 61% for nitrogen‐N, 36% for total phosphate, and 14% for soluble silica during the ice‐free period. Based on observed turbidity levels, the retention of incoming suspended solids is estimated at 65% for the same period. The Wye marsh is a substantial sump for inorganic and organic materials which are retained within the water column, biomass and unconsolidated sediments.
The Occurrence of Bulbella abscondita (Bryozoa, Ctenostomata) in Brackish Waters of Northern Italy
Authors: Jebram Diethardt , Pisano Eva 
Published: February 2007

AbstractThe victorellid bryozoans, Tanganella muelleri and Bulbella abscondita, have been found in the delta of the River Po, Northern Italy. Our finds seem to be the first recorded of B. abscondita in waters in Italy.
The Role of the Limnologist in Ground Water Studies
Authors: Danielopol Dan L. 
Published: February 2007

AbstractThe following topics are discussed: the advantages of an interdisciplinary approach to ground water studies; the porous aquifer as an open system; the problem of the terminology used in ground water ecology; the interest of ecologists in hydrogeological terminology; biological activity in the unsaturated zone of porous aquifers; the distribution of ground water fauna in the saturated zone of porous aquifers; ground water animals as environmental indicators; the manipulation of ground water ecosystems; basic lines for the further development of ground water ecological studies.
A Study of the Excretion and Extracellular Products of Natural Phytoplankton in Lake Nakanuma, Japan
Authors: Watanabe Yasunori 
Published: February 2007

AbstractExcretion of photosynthetic products by phytoplankton in Lake Nakanuma ranged from 8 to 54% of the total carbon assimilated. Percentage of excretion increased under the conditions of high and very low light intensity, low temperature and nutrient deficiency. Estimated daily production of extracellular products in the lake was about 150 mg C/m2 in the summer season and the major components of it were glycolic acid, polysaccharides and polypeptides.
Caractéristiques du microphytobenthos d'un lac volcanique. Characterization of the Microphytobenthos in a Volcanic Meromictic Lake (Lake Pavin, France). II. Productivity and Relationships
Authors: Romagoux Jean‐Claude 
Published: February 2007

AbstractThe collection of microphytobenthos for primary production studies in Lake Pavin was performed with a Jenkin sampler. This corer permits sampling at different levels below the surface of the lake. Five levels (10, 20, 30, 40, and 60 m below the surface) were regularly investigated for more than one year. Each was inhabited by a characteristic population of dominant diatoms. The primary production, which was very large during the summer, decreases with depth. During the winter, the 14C assimilation occurs at a very low rate in clear incubators, but in dark incubators, the rate is high. Therefore, the 14C fixation in darkness is greater than the photosynthetic assimilation. This phenomenon together with the very important data recorded for photosynthetic efficiency (especially at the lowest levels, 40 and 60 m deep) suggest that microphytes on the bottom of the lake assimilate organic compounds during much of the year.
Cave Fauna of Bermuda
Authors: Sket Boris , Iliffe Thomas M. 
Published: February 2007

AbstractSea‐level pools are found in most of Bermuda's known caves. Although the terrestrial fauna of the caves is sparse, a rich aquatic fauna inhabits the pools. While many of the marine cave animals are more or less regular immigrants from open littoral habitats, a number of new species have been discovered, including blind and probably subterranean ones. Zoogeographical connections exist between Bermuda's cave fauna and those of the West Indies and the Mediterranean.
Primary Productivity and Activity Coefficients of the Phytoplankton of a Mesotrophic Soft‐Water Lake (Piburger See, Tirol, Austria)
Authors: Rott Eugen 
Published: February 2007

AbstractPhytoplankton primary production was measured using the14C method once per month from 1973 through 1976 as part of an intensive ecosystem study of a small eutrophic soft‐water lake, under restoration since 1970. Relationships among phytoplankton production, species composition, chlorophyll a content, bacteria, zooplankton and a variety of abiotic environmental factors have been studied. Productivity normally showed one peak in spring and another in summer, whereas a minimum was reached under the ice cover in February or March. Maximum production rates in the depth profile ranged from 3 to 144 mg C · m−3· d−1, integral production from 6 to 510 mg C · m̄−2· d−1. Species of Cyanophyceae, Dinophyceae, Chlorophyceae and Chrysophyceae dominated alternately and showed significant differences in the level and variation of photosynthetic activity. Maximum activity was observed in summer. A high biomass increase during late winter and spring despite low primary productivity resulted from the immigration of the dominant blue‐green alga,Oscillatoria limosa, from the sediment. Energy efficiency increased not only with depth in the light‐limited parts of the euphotic zone but at all depths during bad weather conditions and during the decrease of irradiance in autumn.
Photosynthetic Efficiency in Lawson's Bay on the East Coast of India
Authors: Rao D. V. Subba 
Published: February 2007

AbstractSeasonal variations in the efficiency of utilization of radiant energy by phytoplankton photosynthesis in a tropical embayment followed the same pattern as that of primary production. showing that incident radiation did not limit phytoplankton production. Peak values in primary production and photosynthetic efficiency coincided with periods of nutrient enrichment caused either by upwelling during the southwest monsoon or by run‐off during the northeast, monsoon. A world‐wide comparison of published data on photosynthetic efficiencies in different latitudes showed that higher efficiency is achieved in the tropics, where the values are similar to those observed on phytoplankton cultures. Based on the maximum efficiency of photosynthesis attained, three regimes can be recognized in tropical waters: 1) regions of upwelling with a maximum of 6%,. 2) coastal bays with 0.7%, 3) oceanic regions with 0.24%.
The Nature of Selected Prairie Lake and Stream Sediments
Authors: Oscarson Dennis W. , Rogers J. Scott , Huang Pan M. , Liaw Wen K. 
Published: February 2007

AbstractThe mineralogy and related chemistry of selected lake and stream sediments from the upper Qu'Appelle River basin in southern Saskatchewan, Canada, was examined. The principal crystalline clay minerals present in the colloidal fractions of the sediments are smectite, vermiculite, kaolinite, mica, quartz, and feldspar. The cation‐exchange capacity of the sediments varies from 16.3 to 28.8 meq/100 g, and the pH ranges from slightly acid to mildly alkaline. The hydrous oxides of Al, Fe, Mn, and Si are present in significant quantities in both the colloidal and noncolloidal fractions of the sediments; this is significant because these oxides likely exert the dominant chemical control on the movement of many nutrients and pollutants in aquatic environments. Calcium and Mg carbonates comprise a significant fraction of the sediments. Most of the C in the sediments is in the organic form; the organic C content varies from 1.2 to 6.0%. Because crystalline clay minerals, poorly ordered sesquioxides, and organic matter play a vital role in the retention and cycling of nutrients and pollutants in aquatic environments, a knowledge of the nature and properties of sediments is fundamental to efforts to preserve and improve the quality of natural water systems.
The Mechanics of Penetration by the Fruit of Bidens cernua L (Compositae) into the Cephalic Region of Cyprinids
Authors: Heckman Charles W. 
Published: February 2007

AbstractThe dry, indehiscent fruit of Bidens cernua L. occasionally becomes deeply embedded in the head and jaws of small cyprinids. The tips of the fruit spines are equipped with a set of three barbs. If a fish comes into contact with one of the many such fruits that fall into the water during autumn, one of the barbs can easily penetrate the skin. When the tip of the barb becomes anchored beneath a scale or small bone, movements of the fish will tend to cause the fruit to rotate around that point, forcing the tip of the spine into the flesh by a lever action with a mechanical advantage of about 50. Barbs on the shaft allow the spine to work deeper but prevent its extraction, even when the fruit becomes entangled among submerged plants. Such attachments, which lead to the death of the fish, occur regularly, but not enough fishes are affected to cause serious problems for aquaculturists. The possibility that the decomposing fishes provide nitrogen sources for the sprouting plants is discussed.
Relationship between Chlorophyll‐α Concentration and Phytoplankton Biomass in Several Reservoirs in Czechoslovakia
Authors: Desortová Blanka 
Published: February 2007

AbstractParallel determinations of phytoplankton biomass and chlorophyll‐α concentration were carried out on five reservoirs. Highly significant positive correlations between phytoplankton biomass values and chlorophyll‐α values were found. The possibility of finding a conversion factor linking these two parameters is discussed. The chlorophyll content per unit phytoplankton biomass encountered during the period of study in all reservoirs varied between 0.14 and 3.41% of fresh weight. The influence of light intensity, nutrient concentration and species composition on chlorophyll content per unit phytoplankton biomass is considered.
The Physico‐Chemical and Planktonic Response of an Algicide — Treated Shallow Mountain Lake in Arizona
Authors: Schwartz Steven S. , Blinn Dean W. , Johnson Glen 
Published: February 2007

AbstractThe physico‐chemical and planktonic response and recovery of a shallow mountain lake in Arizona was closely monitored for a 2 1/2 year period following treatment with an algicide. The influential role blue‐green algal blooms exert on seasonal and annual lake dynamics was most obvious once nuisance populations were temporarily removed from the system. Differential sensitivity between algal species was observed. Cryptomonad flagellates were least sensitive to algicide treatment and were dominant during periods when dissolved organic materials appeared to increase. The effect of rotenone application on blue‐green bloom species is discussed.
Inhibitory and Toxic Effects of Blue‐green Algae on Daphnia
Authors: Lampert Winfried 
Published: February 2007

AbstractThe effects of the planktonic blue‐green algae, Aphanizomenon gracile, Synechococcus elongatus, and Microcystis aeruginosa, on survival, growth, and food uptake of Daphnia pulicaria were determined. Synechococcus and Aphanizomenon were unsuitable food when offered alone, but did not affect the daphnids negatively when mixed with Scenedesmus. Microcystis was the only one found to be toxic. In pure suspensions of this blue‐green, the daphnids did not survive more than 48 hours; they lived a little longer if Scenedesmus was supplied additionally. Growth was markedly reduced when only 50 μg carbon/l of Microcystis was added to the normal Scenedesmus food. It ceased at a concentration of 250 μg C/l. This can be explained by the reduction of food uptake. Very small quantities of Microcystis (10 μg C/l) present in the normal food caused a significant reduction of the filtering rate. Filtering inhibition was associated with the cells. Filtrate of Microcystis suspensions was not effective. Thus, the daphnids must ingest the blue‐green cells in order to become toxified. Dual‐labelling experiments showed that Microcystis cells are filtered from the medium by Daphnia with the same efficiency as Scendesmus and are not rejected. Toxicity of Microcystis is considered to be an effective defence mechanism against grazing pressure.
Coral Bioerosion at Enewetak: Agents and Dynamics
Authors: Highsmith Raymond C. 
Published: February 2007

AbstractSignificant differences were found in the extent to which massive coral species at Enewetak are excavated by boring organisms:Goniastrea retiformis, 7.9%;Porites lutea, 2.5%; andFavia pallida, 1.2%.While polychaetes constituted the most abundant and diverse group of coral associates, clionid sponges accounted for approximately 70–80% of skeletal damage. Clionid boring rates are initially very high but burrowing ceases when a particular burrow size (˜0.6 cm) or distance from the surface (≦2 cm) is reached.Most coral skeletal excavation occurs within 2 cm of a dead surface. Therefore, bioerosional damage to corals depends primarily on the amount of skeletal surface not covered by live coral tissue. Damage to skeletons is inversely correlated with colony size but is not correlated with coral growth rates or water depth. Massive corals have a potential escape in size from catastrophic bioerosion.Models relating 1) coral growth forms to skeletal density and stability in currents, 2) resistance of coral skeletons to breakage by water movement and suspended rubble, and 3) dead surface area on coral heads to bioerosional damage and consequent probability of detachment from the substrate, are proposed.
Phytoplankton and Nutrients in Goat Island Bay, New Zealand
Authors: Taylor F. J. 
Published: February 2007

AbstractA quantitative study of the phytoplankton and nutrients in Goat Island Bay, northern New Zealand, was carried out at two stations of depths 7 m and 20 m in 1966‐69. There were significant differences in the concentrations of the phytoplankton at the two stations, the deeper station having, in general, higher concentrations than the shallower.Low phytoplankton standing crops were found in winter when the increased run‐off from the land resulted in lower salinities, higher turbidity, and higher dissolved silicate levels. The spring growth of diatoms was dominated by small diatoms (Cylindrotheca closterium, Leptocylindrus danicus, Nitzschia pseudoseriata, Phaeodactylum tricornutum, and Rhizosolenia delicatula). Occasionally it was dominated by a population of large centric diatoms (Chaetoceros spp., Coscinodiscus spp., Thalassiosira spp.), but these appeared to be found in a separate water mass which entered the bay and displaced the resident water mass. A third water mass entered the bay in spring and was characterised by the coccolithophore Emiliana huxleyi and a lower temperature.During the summer diatoms dominated the phytoplankton population, but were replaced by dinoflagellates for a short period in autumn.
Invertebrate Sampling in the Substratum of an Experimental Recirculating Stream
Authors: Welton J. Stewart , Ladle Michael , Bass Jon A. B. , Chapman Kevin 
Published: February 2007

AbstractIn order to determine the efficacy of sampling benthic invertebrates to a depth of 100 mm as compared with 200 mm, the gravel substratum of an experimental recirculating stream was sampled to both depths. Except for 6 taxa which were significantly more numerous in the shallower samplers, there was no significant difference between the densities determined from the two depths.
Phytoplankton and Epiphyte Development and Their Shading Effect on Submerged Macrophytes in Lakes of Different Nutrient Status
Authors: Sand‐Jensen Kaj , Søndergaard Morten 
Published: February 2007

AbstractThe annual mean light intensity at the depth limit of the Littorella vegetation was 24–33% of the subsurface light intensity, despite large variations in each attenuation component (lake water, phytoplankton, and epiphytes). In oligotrophic, silicate‐poor lakes, the light attenuation above the submerged vegetation was dominated by the water itself, which accounted for 65–72% of the total attenuation. Phytoplankton and epiphytes were equal in importance to each other. In oligotrophic, silicate‐rich lakes and lakes receiving a nitrogen supply above background level, the epiphytes were more abundant, accounting for about 50% of the light attenuation. In one lake with a high nutrient supply, the epiphytes were responsible for 86% of the light attenuation.A new method of measuring the effect of shading by the epiphytic community on submerged macrophytes is presented. The light attenuation caused by the phytoplankton and the epiphytes was investigated and related to the depth distribution of the submerged angiosperm, Littorella uniflora.It is shown that the biomass of the epiphytes increased more than the biomass of the phytoplankton in response to an external or internal nutrient loading. Shading by epiphytes is of decisive importance for the depth distribution of Littorella at increasing nutrient supply.
Toxic Blue‐green Algae Water Blooms Found in some Lakes in the German Democratic Republic
Authors: Henning Manfred , Kohl Johannes‐Günter 
Published: February 2007

AbstractFrom 1977 to 1979 plankton samples were taken from 6 lakes in the German Democratic Republic (GDR) during water blooms and examined for their toxicity to homothermal animals. Microcystis aeruginosa, Aphanizomenon flos‐aquae, Anabaena spiroides, and Oscillatoria redekei were dominant in the samples. With the exception of Oscillatoria redekei the algae tested had toxic effects on mice after intraperitoneal injection. The rate of survival of the test animals was particularly low when the algae were disintegrated by ultrasound or freeze‐drying prior to injection, this indicating the endogenic character of the toxins. Water blooms of Microcystis aeruginosa taken from Lake Pehlitzsee (Eberswalde District) showed the highest toxicity with an LD30 as high as 45 and 43.7 mg/kg, respectively. Injection of the lyophilized cells of Aphanizomenon flos‐aquae brought about the same symptoms in the test animals as in the case of Microcystis, but the LD30 was 200 mg/kg.
The Re‐establishment of Meromixis in Hemlock Lake, Michigan, After Artificial Destratification
Authors: Fast Arlo W. , Tyler Peter A. 
Published: February 2007

AbstractThe limnological characteristics of meromictic Hemlock Lake, Michigan, are outlined. The changes brought about by artificial destratification, and those accompanying re‐establishment of meromixis, are then described. A mechanism for the return of meromixis is suggested, and its events compared with an analogous case in a Tasmanian reservoir.
A Thiobios Does Exist ‐ Gnathostomulid Domination of the Canyon Community at the East Flower Garden Brine Seep
Authors: Powell Eric S. , Bright Thomas J. 
Published: February 2007

AbstractA community of organisms dominated by gnathostomulids has been discovered at the East Flower Garden Brine Seep. This discovery clearly demonstrates that specialized communities of micro‐metazoans exist in and below sulfide‐dependent chemoclines. The term thiobios should be retained to describe these communities.
The Manna Effect: The Structure of Benthic Populations
Authors: Wangersky Peter J. , Wangersky Charles P. 
Published: February 2007

AbstractThe effects of randomness of food supply on the composition of a model community with a single trophic level was studied by the use of a Monte Carlo model. Many of the features of benthic communities, including co‐existence of many species in apparent species mosaics, can be seen to be responses to the random food distribution. Measures of diversity and species dominance may actually be indirectly indicating rate of food supply.
Phytoplankton Losses due to Zooplankton Grazing in a Drinking Water Reservoir
Authors: Horn Wolfgang 
Published: February 2007

AbstractPhytoplankton losses due to zooplankton grazing in the Saidenbach drinking water reservoir were calculated on the basis of laboratory experiments and field studies. The dependence of grazing rate and filtering rate on phytoplankton concentration, temperature and other factors is described.
Paleolimnology of Two Shallow Lakes in Central Alberta, Canada
Authors: Forbes J. R. , Hickman M. 
Published: February 2007

AbstractAn interpretation of postglacial change in water quality and productivity has been made for two shallow lakes in Central Alberta, Canada, namely Hastings Lake (longitude 113° 00′ W; latitude 53° 30′ N) and Lac Ste. Anne (longitude 114° 21′ W; latitude 53° 41′ N). Erosion rates around Lac Ste. Anne have remained constant. Similarly productivity has changed little although macrophytes contributed more to total production during the early stages. Hastings Lake has responded more sensitively to changes in the balance of precipitation and evaporation. From 5500 to 4000 year B. P. it was shallower than at present. Productivity during this early phase was less but macrophytes and allochthonous organic matter (i. e., leaf litter) probably contributed a greater proportion of the organic influx. After water levels rose productivity increased remaining steady until 2500 year B. P. when a slight decline occurred. Throughout the high water period oxygen depletion has not been serious. Any period of reducing conditions has been brief. Productivity has never been nutrient‐limited. Elevation of the lake surface increased potential volume for production and reduced turbulent resuspension of bottom sediments permitting greater light penetration, and enhanced algal production. Difference between the sedimentary record of these two lakes, as well as the two basins of Hastings Lake, demonstrates the individualistic responses of basins and lakes to climatic events.
Determination of the Limiting Plant Nutrient in the Water of Lake Balaton by Algal Assay Procedure
Authors: Dobolyi Elemér , Ördög Vince 
Published: February 2007

AbstractAlgal assays were performed on water samples taken from different sites in Lake Balaton. Selenastrum capricornutum was used in the test to determine the primarily limiting plant nutrient. The results of supplementary nutrient additions to the bottle tests were evaluated by cell counts. The tests have indicated phosphorus as growth rate limiting, and in two cases as biomass limiting plant nutrient, but periodic occurrences of nitrogen limitation cannot be excluded.
Revision of the Genus BosminaBAIRD, 1845 (Crustacea, Cladocera)
Authors: Lieder Ulrich 
Published: February 2007

AbstractThe genus Bosmina can be differentiated into four subgenera: 1. Bosmina s. str. BAIRD, 1845, 2. Eubosmina SELIGO, 1900, 3. Neobosmina LIEDER, 1957, and 4. Sinobosmina LIEDER, 1957. Subgeneric discrimination is based upon several features of the females (postabdominal claw, serration of the mucro, patterns of the lateral head pores) and, mainly, upon certain differences in the morphology of the male (postabdomen and, according to LILLJEBORG 1900, BURCKHARDT 1924 and KOŘINEK 1971, the first leg). The distribution of the Bosmina subgenera throughout the world varies: Bosmina s. str. is distributed worldwide (except for Australia?), Eubosmina is holarctic, Neobosmina has been found in Africa, the neotropical zone, Australia and Oceania, and Sinobosmina occurs in East and South‐East Asia.