bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dispersion of Epiphytic Chironomid Larvae and the Probability of Random Colonization
Authors: Tokeshi Mutsunori , Pinder L. Clive V. 
Published: February 2007

AbstractDispersion of chironomid larvae between and within stands of the aquatic macrophyte Ranunculus penicillatus var. calcareus was studied by sampling individual leaves of Ranunculus. Two of the six common species exhibited no variation in density between sites, while others had significant variations. A new probability density function was applied to the data and it was revealed that random colonization was not uncommon among these epiphytic larvae. It was suggested that stochastic factors are of some importance in the system under study.
Organic Carbon Flux to a Large Salt Lake: Pyramid Lake, Nevada, USA
Authors: Galat David L. 
Published: February 2007

AbstractEnergy flux to a large, deep, salt lake from phytoplankton, periphyton and macrophyte primary production as well as fluvial transport and wind‐transported terrestrial vegetation and dust were quantified. Average areal phytoplankton net photosynthesis was 511 mg C m−2 d−1. Highest rates were during water‐blooms of the bluegreen alga, Nodularia spumigena. Although areal daily net photosynthesis by periphyton in Pyramid Lake was comparable to other salt lakes, annual carbon influx by periphyton was small due to the lake's graben morphology and moderate euphotic depth (mean, 11.9 m). Macrophytes were uncommon and, therefore a minor source of energy.Truckee River is the only major fluvial discharge to Pyramid Lake and dissolved organic carbon was the principal organic carbon fraction in river water. Large upstream water diversions coupled with several drought years resulted in an average fluvial organic carbon load of only 7.3 g Cm−2y−1 or 4% of median phytoplankton net photosynthesis. Tumbleweeds were the most common terrestrial plant material observed in Pyramid Lake comprising a maximum projected importance of 6% of total annual carbon input. Windborne dust represented < .1% of annual carbon input.Phytoplankton primary production is the predominant energy source to Pyramid Lake, accounting for over 80% of annual carbon influx. The relative magnitude of autochthonous and allochthonous vectors to the annual carbon budget of this desert salt lake are comparable to those of the few other large lakes for which detailed energy input budgets have been calculated.
The Ecology of Adontorhina cyclia BERRY (1947) (Bivalvia: Thyasiridae) on the Southern California Borderland
Authors: Jones Gilbert F. , Thompson Bruce E. 
Published: February 2007

AbstractAdontorhina cyclia BERRY, 1947 is widely distributed on the continental borderland of southern California. It is a faunal element in every major habitat type including two of the outer deep basins, Santa Cruz Basin and San Nicolas Basin. On the mainland shelf it is discontinuously distributed from Point Conception to the US/Mexican Border. The depth distribution of Adontorhina reflects the fact that it inhabits both topographic highs and some of the deep basins of the borderland. Its depth range is from 11.6 to 1,886.0 meters. While Adontorhina is able to inhabit a wide range of sediment types, from 1.5 to 8.1 mean phi, it was primarily collected from locations where sediments ranged from 3 to 5 mean phi. A diverse array of macrofaunal taxa is associated with Adontorhina. The numerically dominant taxa varied from habitat to habitat.
Ingestion, Digestion and Assimilation Efficiency of the Sea‐Anemone Aiptasia pallida Fed Zooplankton Prey
Authors: Clayton William 
Published: February 2007

AbstractIngestion time, digestion time, and assimilation efficiency by the sea anemone Aiptasia pallida were studied in the laboratory by feeding individual anemones preweighed pellets of freeze‐dried Artemia salina nauplii. There was no significant correlation between anemone size, measured as dry weight, and either ingestion time, digestion time or assimilation efficiency. Similarly, there was no significant correlation between meal size (i.e., dry weight of ingested brine shrimp pellet) and either ingestion time, digestion time or assimilation efficiency. These results suggest that, under these conditions, assimilation efficiency is unaffected by either “meal” size or anemone size.
Effects of Experimental Acidification on Phyto‐, Bacterio‐and Zooplankton in Enclosures of a Highly Humic Lake
Authors: Arvola Laubi , Salonen Kalevi , Bergström Irin A. , Heinänen Anne , Ojala Anne 
Published: February 2007

AbstractIn situ enclosure experiments were performed in a highly humic lake to examine the effects of acidification on phyto‐, bacterio‐ and zooplankton. The acidity of three enclosures was adjusted with H2SO4 to pH 3.5, 4 and 5 and one enclosure and the lake served as controls. The diversity of plankton as well as the mean concentration of chlorophyll α, primary production and respiration of plankton decreased with increasing acidity. Bacterial density was slightly lower in the pH 3.5 enclosure than in the other enclosures and in the lake, but there were no differences in the morphological type or mean volume of the cells between different treatments. In the acidified enclosures Cryptomonas ovata and Chlamydomonas spp. were the dominant phytoplankters, while Dinobryon and Mallomonas species seemed to be most sensitive to acidity. Keratella cochlearis, Kellicottia longispina and Bosmina longispina were the most tolerant zooplankton to acidity.
A Study of Benthic Communities in Some Saline Lakes in Saskatchewan and Alberta, Canada
Authors: Timms Brian V. , Hammer U. Theodore , Sheard John W. 
Published: February 2007

AbstractThe spring benthos of 22 lakes ranging from 1–88 gl−1 salinity contained 58 species of macroinvertebrates, but only 23 species occurred in waters >3 gl−1. The amphipod Hyalella azteca and the chironomids Procladius freemani, Chironomus nr. muratensis and Cryptochironomus spp. were important at lower salinities (1–12 gl−1) whereas the chironomids Tanypus nubifer, Cricotopus ornatus and Chironomus nr. annularis dominated at moderate salinities (5–30 gl−1) and dolichopodid and ephyrid dipterans were the only species in hypersaline lakes (>50 gl−1). Diversity decreased significantly with increased salinity.Mean dry biomass ranged from 0–9.12 gm−2, showing little correlation with salinity, though hyposaline lakes often had elevated values and hypersaline lakes very low values. Shallow lakes (<5 m) had significantly lower standing crops. There were long term changes in biomass (over 45 years) in some lakes due to cultural eutrophication or secular changes in salinity. Chironomids were by far the dominant contributors to biomass at salinities to 50 gl−1, above which dolichopodid and ephyrid dipterans dominated.The lakes were classified into four groups—subsaline, hyposaline, shallow hypo‐mesosaline and hypersaline, reflecting the importance of salinity and also relative depth as major controlling factors.
A Sediment Penetrometer for in situ Determination of Sediment Type and Potential Bottom Dynamic Conditions
Authors: Håkanson Lars 
Published: February 2007

AbstractComparison of the shear strength at the surface of underwater sediments provides a simple means of characterizing areas of erosion, transportation and accumulation. A triple cone penetrometer has been developed to obtain relative sediment penetration data, in situ. Following calibration of the instrument on selected samples from lakes and coastal areas, relative data are used to characterize a wide range of bottom types. The cone data are useful in, e.g., contexts of coastal planning and aquatic pollution control, i. e., in matters where sediment distribution maps for entire lakes and coastal areas are requested rather than detailed information from specific sites. The instrument provides rough but objective data on sediment type without samples being taken and laboratory analysis being done. The total weight of the instrument is 7.5 kg, which makes it easy to operate by hand from a small boat.
Effects of Phosphorus Removal on the Maximal Algal Growth in Bioassay Experiments with Water from Four Dutch Lakes
Authors: van der Does J. , Klapwijk S. P. 
Published: February 2007

AbstractThis paper reports the effects of phosphorus removal at three sewage wastewater treatment plants on the state of eutrophication of four shallow lakes in the south‐eastern part of the Rijnland Waterboard area during the years 1980–1982. With chemical analyses and bioassay experiments using the natural phytoplankton population no significant lowering could be detected of respectively the phosphate concentration and the maximal algal growth potential. All lakes proved to be principally nitrogen limited except the Reeuwijk Lakes, which showed clearly, after a primary nitrogen limitation, a secondary phosphorus limitation. Therefore the main attention with respect to phosphorus reduction should be concentrated on the Reeuwijk Lakes in the first place. For the other lakes in the investigated area phosphorus removal will, when it is the only measure taken, presumably not lead at short notice to a decrease of the algal biomass.
Structure, Dynamics and Production of Mesozooplankton Community in the Bothnian Bay, Related to Environmental Factors
Authors: Kankaala Paula 
Published: February 2007

AbstractStudies on the zooplankton community of the Bothnian Bay (BB), the northernmost basin of the Baltic Sea, were carried out in 1976–78. Only 8–14 taxa dominated in the zooplankton community. The highest abundances and biomasses occurred during the warmest period or immediately afterwards, in July–September. The production of zooplankton was estimated to be 3.1–7.8 g C · m−2. a−1 in the coastal area and 2.5–3.6 g C · m−2 · a−1 in the open sea. During the short growing season (June–September) the biomass turnover took place in about 11 days. The productivity of zooplankton is discussed in relation to available food of both autochthonous and allochthonous origin and compared with the other parts of the Baltic Sea.
Productivité comparée des deux étangs situés à proximité du lac Saint‐Jean, au Québec
Authors: Lalancette Louis‐Marie 
Published: February 2007

The Comparative Productivity of Two Ponds in the Vicinity of Lake St‐John, QuébecIn 1980 and 1981, the productivity of two ponds near Lake St. John were evaluated. One, the pond of Desbiens, did not communicate with Lake St. John and the other, the pond of St‐Gédéon, was connected to the lake. The aim of this study was to evaluate the contribution that a pond could make to the increase in productivity of Lake St. John which is a reservoir. The pond of Desbiens is more productive than Lake St. John but two to three times less than the pond of St‐Gédéon. The pond of Desbiens shows an advanced degree of eutrophication whereas the pond of St‐Gédéon is similar to the northern lakes by its physico‐chemistry, zooplankton, sediments and benthic fauna. If we want to create artificial ponds, for a better productivity of reservoirs, it is important that they be connected to each other.
Phosphorus Flux Through a Littoral Ecosystem: The Importance of Cladoceran Zooplankton and Young Fish
Authors: Kairesalo Timo , Seppälä Timo 
Published: February 2007

AbstractFoodchain relationships in water within a helophytic vegetation stand were experimentally investigated using the radioactive isotope 33P as a tracer. The results proved the importance of cladoceran zooplankton (mainly Bosmina longispina LEYDIG) in the control of phytoplankton and the importance of young fish in the control of Bosmina abundance in the littoral water.
Plankton Ecology in Relation to Flushing Rate in Four Newfoundland Ponds
Authors: O'Connell Michael F. , Andrews Cater W. 
Published: February 2007

AbstractA seasonal quantitative study was conducted on the plankton of four Newfoundland ponds. There are indications that one pond received inputs of airborne pollutants emanating from a phosphorus plant. All ponds are characterized by high flushing rates. Highest numbers of both phytoplankton and zooplankton organisms tended to occur from late spring through summer, the period of greatest water retention. The phytoplankton was dominated for the most part by nano‐plankton forms. Large blooms of Anabaena flos‐aquae and Asterionella formosa occurred during summer in the pond located near the phosphorus plant. This did not occur in the other ponds. Dominant microcrustaceans encountered included Holopedium gibberum, Diaptomus minutus, and Epischura nordenskiöldi. Of the rotifers encountered, collectively the most important forms were Polyarthra dolichoptera, Conochilus unicornis, Keratella cochlearis, Kellicottia longispina, Kellicottia bostoniensis, Pleosoma truncatum, Synchaeta sp., and Trichocerca sp. Aspects of the ecology of the phytoplankton and zooplankton are discussed in the context of water retention characteristics. A comparison is made with a pond subject to pollution from rural and urban sources. This pond also possesses a high flushing rate.
Reaeration of Oxygen in Shallow, Macrophyte Rich Streams: II. Relationship between the Reaeration Rate Coefficient and Hydraulic Properties
Authors: Thyssen Niels , Erlandsen Mogens 
Published: February 2007

AbstractThe rate coefficient K2 of the physical exchange of oxygen between flowing water and the atmosphere is dependent on water temperature and the hydraulic variables: mean velocity of flow U, mean depth H, and slope S of the stream channel.36 equations from the literature predicting K2 on basis of combinations of U, H and S have been tested against 144 corresponding measurements of K2 and hydraulic variables taken in 10 reaches in 6 Danish streams with different development of the submerged macrophyte community.A statistical analysis showed that all equations except one had to be rejected. To improve predictive accuracy an equation K2 (20 °C) = 8784 U0.734H−0.420 S0.930 was developed applying multiple linear regression. This equation allows K2‐predictions for streams where the hydraulic variables U range from 0.06 to 0.52 m s−1, H from 0.12 to 1.37 m and S from 0.3 to 7.4 × 10−3 m m−1, respectively.Using this equation the lower and upper 95 % limit of confidence for a given K2‐prediction (K2p) are K2p/1.95 and K2p × 1.95, indicating that such equations at best approximate the real K2. Therefore K2 should preferably be measured.
Further Developments of Macrozoobenthos in Lübeck Bay, Following Recolonisation in 1980/81
Authors: Gosselck Fritz , Doerschel Fred , Doerschel Tina 
Published: February 2007

AbstractThe macrozoobenthos in Lübeck Bay (West Baltic) was investigated from 1982 to 1985. The bottom water layer is characterised by oxygen deficiency or even presence of H2S at depths greater than 20 m in late summer and autumn, when the benthic fauna lacks diversity and consists only of Halicryptus spinulosus, Polydora ciliata and Diastylis rathkei. The influx of oxygen‐rich water into the region is followed by rapid colonisation by opportunistic species (Capitella capitata, Polydora ciliata) which are joined by predacious species, such as Harmothoë sarsi, Halicryptus spinulosus, and Anaitides maculata. Bivalve larvae are carried in by the current. It is assumed that, if the hydrographic conditions remain uniformly favourable, damaged regions will be recolonised after a year by drifting larvae and, for a few species, by adult immigration.
Patterns of Reproduction of Pontocaspian Relict Paramysis lacustris within Distribution Area
Authors: Khmeleva N. N. , Baichorov V. M. 
Published: February 2007

AbstractReproduction has been studied of Paramysis lacustris, pontocaspian relict, in the centre of its natural area, and in southern and northern zones of acclimatisation. Life cycles of the animals are identical in the distribution area. The effect of female size on fecundity is only slightly expressed within each generation. Significant correlations of these indices were obtained in seasonal aspect. Specific fecundity is represented by maximum values in the centre of the area and declines in the north‐western direction of introduction. The relation of fecundity to egg weight reflecting correlation of K‐r reproduction strategy is reduced in the regions of introduction. Reproduction effort, i.e. ratio of eggs weight to female weight, is the most stable index within the distribution area. Cumulative potential growth, including soma as well as generative products, was nearer in spite of considerable temperature difference in animal growth.
Survival and Reproduction Potential of Philodina roseola (Ehrenberg) (Rotatoria, Bdelloida) under Various Temperature Conditions
Authors: Lebedeva L. I. , Gerasimova T. N. 
Published: February 2007

AbstractSurvival data, in addition to data on growth and reproduction rate, are necessary to estimate rotifer productivity under various thermal conditions. A method of individual culturing of Philodina roseola helped the authors to obtain data concerning length of life span and realisation of reproduction potential at different temperatures, ranging from 9 to 35 °C. The method also was helpful in revealing the causes of individual deaths. It is shown that at a temperature of 20 °C net reproduction rate (R0) of Ph. roseola is maximum and is equal to reproduction potential of the individual. The peculiarity of Philodina ontogenetic reaction to temperature beyond optimum is the impairment of reproduction process.
Considerations on Benthos Abundance in Freshwaters, its Factors and Mechanisms
Authors: Kajak Zdzislaw 
Published: February 2007

AbstractVariations in biomass and maximal biomasses observed are reviewed. Trophic conditions are considered to be the main factor affecting both nonpredatory and predatory benthos abundance. Competition and predation by invertebrates seem to adjust the abundance of nonpredatory benthos to trophic conditions; both of these processes are influenced by fish. Examples of the role of benthos in ecosystems are reviewed.
In‐situ Monitoring of Water Quality on the Basis of Spectral Reflectance. Ship‐borne Experiments for the Development of Remote Sensing Algorithms Especially for the Estimation of Algae Content in Natural Waters
Authors: Mittenzwey K.‐H. , Gitel'Son A. A. , Lopatchenko A. A. , Sukhorukov B. L. , Voigt T. 
Published: February 2007

AbstractWhen using in‐situ methods such as the use of spectrometers aboard a ship, aircraft or satellites to estimate suspended matter (especially phytoplankton concentrations) in waters it is necessary to know the corresponding correlations between the matter concerned and the spectral reflectance R(Λ) or colour indices R(Λi)/R(Λj).Therefore, ship‐borne experiments were carried out on mesotrophic and eutrophic waters. The following parameters were measured: reflectance at the wavelengths 450, 550, 670, 705 nm, Secchidisk transparency, chlorophyll‐a concentration, fluorescence, extinction, and scattering.Significant correlations (0.92<r2<0.99) were found between chlorophyll‐a concentration (10 to 360 μg/l) and the reflectance ratios R(705)/(670), R(705)/R(550), (R(705) ‐R(670))/R(550). At these concentrations the estimation of chlorophyll‐a by means of R(705)/R(670) appears to be more accurate than by the fluorescence method. When developing methods for estimating seston concentrations the use of R(705) is recommended.
Relationships between diatom assemblages and physico‐chemical variables in the river ter (NE Spain)
Authors: Sabater Sergi , Sabater Francesc , Armengol Joan 
Published: February 2007

AbstractIn the search for the causes of diatom assemblage distribution, a combination of two multivariate analyses has been used. Principal component analysis and canonical correlation analysis have allowed us to find suitable relationships between biological and physicochemical parameters. As a result, water salinity and pollution have appeared as the two main factors which determine diatom assemblage distribution. Reservoirs act as discruptors of the water characteristics, and have an improving effect in the two above factors, which leads to a different diatom community.
Ecology of some Species of Thiobacillus and Sulfate‐reducing Bacteria in the Middle Course of the River Guadalquivir (Spain)
Authors: Fernández Aniceto López , Vilda Eladio Anchia 
Published: February 2007

AbstractDuring 1985, a study was made of the physical, chemical and biological characteristics of the River Guadalquivir. At the same time, the density of certain microorganisms involved in the transformation of sulfur compounds in the water was studied. The results obtained give the following numerical order of density:T. thioparus >sulfate reducers > T. denitrificans > T. thiooxidans. Urban waste was found to increase density levels of these microorganisms. Their relationship with certain environmental parameters is discussed in this study. Regression equations have been obtained of bacteria numbers for three of the four groups studied, using water temperature and permanganate oxidability as dependent variables.
Long‐term Changes in Littoral Habitats and Communities in Lake Mikolajskie (Poland)
Authors: Pieczyńska Ewa , Ozimek Teresa , Rybak Jan Igor 
Published: February 2007

AbstractLake Mikolajskie is seriously affected by Mikolajki town and tourism. The amount of sewage entering the littoral zone is increasing as also is the area of the artificially transformed shore. During the past 20 years the area occupied by macrophytes has decreased markedly. The decline of Phragmites australis, changes in species composition, and reductions in biomass and in the depth‐range colonized by submerged plants have been observed. Simultaneously the biomass of algae has increased markedly. Animals characteristic of polluted sites have become more abundant. Changes in animal numbers result to a great extent from changes in the availability of natural substrates.Zonation of the occurrence of organisms has been observed for years on sites directly affected by sewage—quantitatively and qualitatively poor communities are found at sewage discharge points and the richer ones at a greater distance in the zone fertilized by diluted sewage.
Nitrogen as a Factor Affecting Algal Growth Potential of an Oligotrophic Coastal Environment of Eastern Mediterranean Sea
Authors: Ignatiades L. , Moschopoulou N. 
Published: February 2007

AbstractPotential nitrogen limitation to chl a production in surface waters of Saronicos Gulf, Aegean Sea was assayed using the alga Pavlova lutheri as the test organism. The oligotrophic and eutrophic water types of this area were compared by in situ and in vitro chl a production estimations. Additions of ammonium alone as well as in combination with complete nutrient enrichment were made to the oligotrophic waters and the algal growth yield was determined and compared with the corresponding yield in unenriched water cultures. The results from routine nutrient analysis and bioassay experimentation support the view that nitrogen has a priority among the factors limiting phytoplankton growth in the Eastern Mediterranean Sea.
Energy Transfer in a Kashmir Himalayan Sar (Lake)
Authors: Vaas K. K. , Raina H. S. , Langer R. K. , Sunder Shyam 
Published: February 2007

AbstractThe energy transfer at different trophic levels in a temperate lake ecosystem locally called Sar (lake) has been investigated. Total phytoplankton production in terms of energy fixation has been estimated at 3.2 × 106 cal m−2 y−1, out of which the fish harvest amounts to 2640 cal m−2 y−1. The conversion efficiency from phytoplankton to fish has been estimated at 0.082 %. Apart from other ecological parameters discussed in the paper, suggestions for the efficient use of other available energy from the system has been highlighted.