bluuebunny/crossref_metadata_2025 huggingface dataset:
Veränderungen im Phosphatgehalt des Wassers in einem Prielsystem im Wattengebiet nahe der Nordstrander Bucht (östliche Nordsee) im Verlauf einer Tide Changes in the Phosphate Content of Water in a Tidal Channel through the Wadden Sea near Nordstrander Bight (Eastern North Sea) during a Tidal Cycle
Authors: Lillelund Kurt , Berghahn Rüdiger , Diercking Reinhard
Published: February 2007

The total phosphate content of the water in a well delimited region of the Wadden Sea (26.8 km2) was determined by multiplying the concentration by the water volume during each phase of the tide. When the weather is moderate, sharp but stable gradients are observed from the shore to the open sea resulting from the remineralization processes that occur most rapidly near the shore.
Bioaccumulation and Partitioning of Cadmium within the Freshwater Mussel Dreissena polymorpha Pallas
Authors: Bias Rüdiger , Karbe Ludwig
Published: February 2007

Kinetics of uptake, partitioning and elimination of cadmium were investigated in experimental studies with the freshwater mussel, Dreissena polymorpha. The radioactive cadmium isotopes 109Cd and 115Cd were used as tracers. Shells, soft parts and body fluid of the mussel exhibited considerable differences in accumulation and elimination. Accumulation factors up to more than 70,000 were calculated for the periostracum, whereas accumulation factors for the whole mussels ranging up to 3,000 were calculated. The shells bound a great deal of cadmium, but only loosely, and the metal could be readily eliminated after transfer to uncontaminated water. In contrast, no significant amounts of the cadmium incorporated in the soft parts were eliminated. The results indicate that the major portion of cadmium in the soft parts is strongly bound and cannot be eliminated by exchange processes.
The Development of Vertical Migration Patterns in the Sediments of Estuaries as a Strategy for Algae to Resist Drift with Tidal Currents
Authors: Heckman Charles W.
Published: February 2007

The phenomenon of massive algae migrations to the surface of mud flats at low tide was quantitatively investigated. Differences were noted in the behavior of the individual species. This adaptation to the tidal rhythm is obviously effective for preventing the algae from drifting to the sea, and its development can shed much light on the natural history of the species involved. Euglena obtusa and Caloneis amphisbaena var. subsalina apparently arose by a natural selection process among ancestors from lentic freshwater bodies, while Navicula salinarum, Cylindrotheca signata, and several other diatoms probably invaded the freshwater habitat from marine mud flats, where they were preadapted to the tides.
Eisen und Mangan in pazifischen Tiefsee‐Rhizopoden und Beziehungen zur Manganknollen‐Genese Iron and Manganese in Pacific Deep‐sea Rhizopods and Relationships to Manganese Nodule Formation
Authors: Riemann Franz
Published: February 2007

The Pacific deep‐sea bottoms are dominated by rhizopodan Protozoa. Their abundance on manganese nodules and in the associated sediments suggests a contribution to nodule formation, though direct evidence is still lacking. Attention is called to iron contents in solid excretion products of some sessile rhizopods that may contribute to the initiation of manganese deposition and nodule growth. Manganese is scarce in the faecal pellets of sediment‐dwelling rhizopods. This is discussed in context with questions regarding manganese mobilization in pelagic sediments.
Ecological Study of Freshwater Zooplankton of a Subtropical Pond (Karnataka State, India)
Authors: Patil C. S. , Gouder B. Y. M.
Published: February 2007

Fortnightly records of the biotic and abiotic conditions in a subtropical natural pond were made over a period of 14 months with a view to find out the abiotic causes of fluctuations in the zooplanktonic populations. Statistical analysis of simple correlations among the abiotic factors revealed direct relationships between water temperature, DO and pH and an inverse relationship between DO and ‐PO4 at statistically significant levels (P<0.01). The relationships between the physical and chemical factors and the zooplanktonic groups were evaluated by partial and multiple correlation coefficients. The causes for variation in the populations were established by stepwise multiple regression analysis. The populations of copepods and rotifers, respectively, were correlated at the 5 % and 1 % levels of significance to conductivity and ‐PO4 which might be indirectly affected by bicarbonates and phytoplankton growth. The occurrence of two peaks of zooplankton, one in winter and another in postsummer, were observed to follow the Microcystis aeruginosa bloom.
Some Physical and Chemical Properties of Water from an Undisturbed Tropical Catchment Area (Guma Dam, Sierra Leone)
Authors: Mtada Obed S. M.
Published: February 2007

The water had a very low content of total suspended solids (<1 mg l−1), but its transparency was high (5–8 Hazen units). The concentration of Mg++ and Ca++ were below 1 mg l−1, but that of SiO2 was 5.3 mg l−1. Free CO2 was abundant (15.3 mg l−1) and the pH was low (<6.5). These conditions were accompanied by low concentrations of PO4‐P, total iron and NO3‐N. The DO content of the water was always below 80 %, but the chloride concentration (8.4 mg l−1) seems relatively high for this type of freshwaters. It is, however, much lower than that known for arid areas. It is concluded that the geology and vegetation dominate the chemistry of the water from the Guma Dam catchment area. The influence of man is acknowledged only in as far as he has protected the catchment area.
Recording the Motor Activity of Aquatic Animals by Ultrasound
Authors: Rosenfeld Eike , Millner Rudolph , Grosse Wolf‐Rödiger , Schuh Joseph
Published: February 2007

An ultrasonic technique based on the Doppler effect is presented to allow the registration of aquatic animal movements. The method was tested on crucians (Carassius carassius) in an aquarium as part of chronobiological investigations. Comparison with light barrier measurements shows that the Doppler technique is suitable for detecting typical circadian and seasonal changes in the motor activity of the fishes. The features of the ultrasonic method are discussed.
Marine Benthos in Relation to Pore Water Chemistry and Sediment Geochemistry of Simulated Dredged Material
Authors: Maurer Don , Church Thomas M. , Wethe Charistian , Lord Charles
Published: February 2007

During the course of study on vertical migration and mortality of benthos in simulated dredged material, changes in pore water chemistry and sediment geochemistry were also examined. Dissolved oxygen, ammonia, and sulfide showed significant changes between overlying water and pore water over the two week experimental period. Chemical effects in dredging operations can be important on infaunal organisms.
Primary Production and Effects of Enrichment with Nitrate and Phosphate on Phytoplankton in the Barra Bonita Reservoir (State of São Paulo, Brazil)
Authors: Henry Raoul , Hino Kozo , Gentil José Geraldo , Tundisi José Galazia
Published: February 2007

Primary productivity of the phytoplankton was evaluated by the 14C and dissolved oxygen methods in December 1981 at the Barra Bonita Reservoir (São Paulo State, Brazil). The primary production varied between 0.17 to 14.51 mg C m−3h−1 at 4 and 0 m depth, respectively. About 57 to 94% of the photosynthetic activity was due to phytoplankton > 50 μm. The highest value of assimilation rate (3.36 mg C mg Chl−1h−1) was found in the surface water. Dissolved nutrient concentrations were very high and consisted mainly of nitrate. Light penetration was low, the aphotic zone accounting for about 90% of the water column. Enrichment with nitrate and phosphate showed that both N and P stimulated the production of biomass (chlorophyll a), mainly due to the addition of phosphate. The enrichment experiment also indicated that phosphate addition has a significant stimulatory effect on the growth of Melosira sp. The limiting effect of light penetration on photosynthetic activity is more severe than that of nutrients.
Investigations into the Food Selectivity of the Planktic Crustaceans Daphnia hyalina, Eudiaptomus gracilis and Cyclops vicinus
Authors: Horn Wolfgang
Published: February 2007

The food selectivity of Daphnia hyalina, Eudiaptomus gracilis and Cyclops vicinus was investigated in laboratory experiments using algae of different sizes and at different concentrations as food sources. Vanderploeg and Scavia's (1979a, b) coefficient, which is most suitable for characterising selectivity, was selected from the literature and used to analyze the results. None of the three species was found to feed selectivity, however. The results show, on the other hand, that the leaky‐sieve model can be used to describe the feeding patterns of these species. There were clear differences between the particle size ranges consumed by our experimental species, and these showed that, during the experiments, Daphnia hyalina acted as a microfilter‐feeder, whereas Eudiaptomus gracilis and Cyclops vicinus acted as macrofilter‐feeders.
Methods of Modelling the Age Dependent Ration Changes of Plankton Crustaceans Feeding on Variable Quality Food
Authors: Gruzov Lev N.
Published: February 2007

Methods of formalizing trophic interactions within plankton communities are discussed on the basis of correlations observed between prey size and specific and age‐dependent features of the consumer. The nature of the functional reaction of copepods to changes in food quality is specific to the different age groups. Allometric types of relation between food ration and body size cannot describe these phenomena. An alternative method based on the notions of minimum, maximum and optimum prey size changing in the course of ontogeny is suggested. The values of the parameters are identified for the species of Temoridae and Acartiidae (Copepoda, Calanoida), and a range of examples proves satisfactory reproducibility of the experimental data concerning mono‐ and polyphagy. This paper presents a biological interpretation of the parameters that suggest their functional connection with mesh size, mouth size and the ability of copepods to dismember large objects into portions. Optimum food size is expressed as a function of age and size of modal class particles that enabled “switching” of food as a result of changes in the component ratio in the environment and different capturing capabilities to be modelled. Some conclusions resulting from the model are discussed.
The Benthic Macrofauna Associated with the Oyster Reefs of the James River Estuary, Virginia, U.S.A.
Authors: Larsen Peter F.
Published: February 2007

Productive, natural oyster reefs within the James River estuary, were quantitatively sampled for associated macrofauna for a year. The 192 samples yielded 142 taxa. Mean faunal density on these reefs ranged from 5,757 to 57,857 m−2. Over 770/0 of the individuals collected belonged to 11 taxa. The number of species and informational diversity (H') decreased up the estuarine gradient.

The quality of available shell surface was deemed important in determining density. The spatial heterogeneity provided by the shell surface allowed development of a densely populated, diverse faunal assemblage which differs from soft‐bottom assemblages principally in quantitative aspects. The assemblage is not spatially or temporally homogeneous and undergoes significant changes in community structure both seasonally and along the estuarine gradient.
An Examination of Cell Volume in Dominant Phytoplankton Species of the Central and Southern Adriatic Sea
Authors: Viličić Damir
Published: February 2007

The phytoplankton biomass expressed as total cell volume is often of doubtful value due to cell size and volume variations in the organisms present. Cell volume calculations for 95 phytoplankton species and volume‐frequency diagrams for 25 dominant species were analyzed for the Adriatic Sea. Recommendations for more precise work dealing with phytoplankton cell volume and biomass are given. Temporal variations in the average microplankton cell volume are presented and discussed.
Limnological Observations on Rihand Reservoir (Uttar Pradesh) with Reference to the Physical and Chemical Parameters of its Water
Authors: Singh R. K.
Published: February 2007

Observations in respect of Rihand Reservoir based on monsoon inflow, reservoir level, evaporation loss, air and water temperature, rainfall and wind velocity have been discussed in relation to the physical and chemical parameters of the water body. A weak thermocline has been observed, and the water showed a biogenic chemical stratification during the warmer months. Rihand is a monomictic tropical lake with a moderate nutrient supply, but is not very productive from the limnological point of view. The nutrient content of this lake declined from 1972 to 1974, but improved in 1975 and 1976 with the increase in rain and inflow of water. The productivity of the reservoir depends greatly on the nutrient level of the inflowing water from the catchment area, so that the monsoon inflow largely influences the water quality of the reservoir.
Desmids of Iraq
Authors: Nurul Islam A. K. M. , Yousuf Haroon A. K.
Published: February 2007

Forty species and varieties of desmids belonging to the genera Closterium (7), Pleurotaenium (1), Euastrum (3), Cosmarium (28) and Staurastrum (1) have been described from southern Iraq including two new varieties under Cosmarium (i.e. C. cyclicum Lund, var. mesopotamianum var. nov., and C. tyrolicum (Nordst.) Krieger & Gerloff var. minor var. nov.). Most of the taxa are new records for Iraq.
Seasonal and Spatial Distribution of Iron Precipitating Heterotrophs in Water and Sediments of Fish Ponds of Differing Farming Managements
Authors: Jana B. B. , Patel G. N.
Published: February 2007

Population densities of primarily iron precipitating heterotrophs (metal‐precipitating non oxidizing bacteria) were estimated in water and sediments of ponds being used for polyculture, monoculture and traditional systems of fish farming over a period of two and a half years. Spatial differences in microbial density in the ponds were related to the organic loading of the farm site and the type of farming. The highest bacterial populations occurred in November and the lowest in summer. Nitrite concentration was mainly responsible for such seasonal changes.
Effects of Oil Refinery Effluents on Selenastrum capricornutum PRINTZ
Authors: Gaur J. P. , Kumar H. D.
Published: February 2007

Laboratory‐based bioassay experiments using Selenastrum capricornutum PRINTZ as the test organism were conducted to evaluate the potentiality of refinery effluents to sustain algal growth. The raw effluents were remarkably toxic to the test alga, but satisfactory algal growth occurred in (diluted) 0.01 % effluents. The effluents from subsequent treatment stages required much less dilution to eliminate the toxicity. This study implicates oil and phenol in the reduction of algal growth in refinery effluents. A highly significant negative correlation was found between the final yield of the test alga and the concentration of oil or phenol in the culture suspension. The bioassay experiments therefore point to the toxic nature of refinery effluents. On the basis of these findings it is recommended that proper dilution of refinery effluents is necessary before they are discharged into any body of water.
Morphological Form Variation in a Loricate Rotifer, Keratella tropica APSTEIN from a Perennial Pond, Janaktal, Gwalior, India
Authors: Saksena D. N. , Sharma S. P.
Published: February 2007

Morphological form variation in a loricate rotifer, Keratella tropica APSTEIN is decribed. Form variation in this rotifer involves appearance and development of the left postero‐lateral spine. The right postero‐lateral spine varies, too. It increases with increasing length of lorica and left postero‐lateral spine. Three morphological forms, viz. reducta, asymmetrica and heterospina are recognized.
Role of Unionidae and Sphaeriidae (Mollusca, Bivalvia) in the Eutrophic Lake Zbęchy and its Outflow
Authors: Kasprzak Krzysztof
Published: February 2007

The abundance, biomass, respiration, and filtration rate of the Unionidae and Sphaeriidae and their significance to the phosphorus cycle was estimated in an eutrophic lake in Poland, situated in an agricultural area, and in its outflow canal. A decrease in Unionidae biomass was compensated for the Sphaeriidae in terms of both biomass and filtration rate. Depending on the developmental state of the Unionidae and Sphaeriidae populations, the volume of pumped water, the amount of removed and assimilated seston and the phosphorus excretion changed significantly.
Deposition and Decomposition of Turtlegrass Leaves
Authors: Newell Steven Y. , Fell Jack W. , Miller Christine
Published: February 2007

In coastal zones where prevailing winds are onshore, seagrasses are regularly deposited at the shoreline, often forming large accumulations. We have compared the rates of output of dry matter, organic carbon, and nitrogen for turtlegrass (Thalassia testudinum) when it decays at the shoreline or continuously submerged nearby. Output rates were either delayed (by 30 days or more) or were significantly slower for decay under submerged conditions.
Interactions of Physical, Chemical and Biological Processes in Depth and Time within a Productive English Lake during Summer Stratification
Authors: Heaney S. I. , Smyly W. J. P. , Talling J. F.
Published: February 2007

A survey is given of physical, chemical and biological events in the water‐mass of a productive lake (Esthwaite Water, N. England) during summer stratification. They are interrelated in terms of i) responses to meteorological changes (ii) susceptibility to density stratification (iii) participation in acid‐base and redox systems, with interactions of these (iv) modification due to the generation of particulate material from soluble precursors (v) limiting factors in such bio‐generation (vi) mechanisms of internal nutrient loading, and (vii) control by the characteristics of individual plankters. The significance is demonstrated of differential inputs of meteorological variables, and especially of biological production and degradation, for determining the overall structure and metabolism of the lake.
Dispersion of Epiphytic Chironomid Larvae and the Probability of Random Colonization
Authors: Tokeshi Mutsunori , Pinder L. Clive V.
Published: February 2007

Dispersion 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

Energy 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

Adontorhina 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

Ingestion 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

In 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

The 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

Comparison 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

This 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

Studies 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, Québec

In 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

Foodchain 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

A 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

The 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

The 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

Reproduction 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

Survival 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

Variations 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

When 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

In 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

During 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

Lake 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

Potential 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

The 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.
Experiments on Nitrogen and Phosphorus Release by Chironomus ex gr. plumosus from the Sediments of Lake Balaton, Hungary
Authors: Tátrai István
Published: February 2007

Sediment‐water systems of Lake Balaton mud and tap water were constructed in plexiglass tubes and boxes for evaluation of changes in the nitrogen and phosphorus contents of overlying water as influenced by chironomid density and light conditions.

Nitrogen flux from sediment was greatly influenced by denitrification process. The amount of TN released by chironomids amounted to about half of the yearly nitrogen fixation rate in Lake Balaton.

Omnivorous chironomids increased the phosphorus content of the overlying water. The rate of release was density dependent. TP release rates ranged between 1–17 mg m−2 day −1 over a range of densities 500–20,000 larvae m−2.

It became evident that aerobic sediment cores can be an important nutrient source in lakes where chironomids inhabit them at densities above 1,000 larvae m−2.
Enzymatic Evaluation of Oxidation Pond Performance
Authors: Hosetti B. B. , Patil H. S.
Published: February 2007

A one year study on a waste oxidation pond was undertaken to observe the behaviour of four enzymes, viz catalase, phosphatase, protease and amylase with respect to other ecological factors. The increase in solar radiation from March to May enhanced phytoplankton growth resulting in increased pH and DO and considerable reduction in nutrients and BOD. Variations in the activity of enzymes seemed to be directly related to bacterial number. The activity of catalase and phosphatase seemed to be related to the microbial density and nutrient status of the pond. The activity of protease and amylase could be used as a measure of degradation of organic matter.
A Remark on Microorganisms in Lake Sediments with Emphasis on Polyphosphate‐accumulating Bacteria
Authors: Uhlmann Dietrich , Bauer Hans‐Dietrich
Published: February 2007

Bacteria which are able to store large amounts of phosphorus as polyphosphate (PP) under aerobic conditions and to release it under anaerobic conditions are utilized for the advanced treatment of sewage. This note presents some results which indicate that PP‐accumulating bacteria which possibly participate in the immobilization and release of dissolved phosphate may also be present in lake sediments.
Comparison of the Benthic Size Structure Between Sublittoral, Upper‐slope and Deep‐Sea Areas of the Western Pacific
Authors: Shirayama Yoshihisa , Horikoshi Masuoki
Published: February 2007

Benthic size structures were compared between sublittoral, upper‐slope and deep‐sea areas of the Western Pacific using the mesh‐size fractionated distribution of organisms. The average size of the individuals became smaller with increasing water depth, suggesting that the dwarfism is a more common phenomenon than the gigantism in the deep sea. Nonetheless, the mesh size of 0.037 mm was fine enough to retain meiobenthic specimens quantitatively. When the whole benthos was divided into macro‐ and meiofauna, the size distributions overlapped considerably in a mesh‐size fraction between 1.0 and 0.5 mm. In this fraction, the meiofauna predominated over macrofauna in the deep sea, while the opposite applied to the shallower depths. From these results, recommended mesh sizes of the sieves for the studies of macro‐ and meiobenthos were proposed.
Herbivores and the Spatial Distributions of the Phytoplankton. I. The Plankton Market
Authors: Wirick Creighton D.
Published: February 2007

Planktonic herbivores forage on phytoplankton cells which were produced at some earlier time and at a distant place. A steady state, one dimension model of the birth, death and eddy diffusion of phytoplankton illustrates phytoplankton smooth both temporal and spatial variations as they are transported. When the eddy diffusivity is k and the phytoplankton doubling time is b, the average distance traveled by a phytoplankton cell is (kb)1/2 and the average time spent doing so is b. Only those spatial variations with wavelengths greater than 2π(kb)1/2 and temporal variations with periods greater than 2πb will be observed in the phytoplankton distributions at more than half their original amplitude. Both k and b control the length scale of phytoplankton distributions in a cartesian coordinate system. Planktonic herbivores view the phytoplankton from a diffusing coordinate system in which the spatial scales of the phytoplankton distribution are transformed into time scales.
Central Asian Irrigation Canals and some Aspects of their Algal Flora
Authors: Ergashev A. E.
Published: February 2007

A general description is given of major Central Asian canals and their differences in age, morphometry, flow feed, total dissolved solids, thermal regime, transparency as well as algal flora and its quantitative development.
Variation of Phytoplankton in a Tropical Estuary (Vellar Estuary, Bay of Bengal, India)
Authors: Krishnamurthy K. , Mani P. , Krishnamurthy K.
Published: February 2007

The phytoplankton species composition and community structure were studied at two stations in the Vellar estuary from January to December, 1983. A total of 117 species of phytoplankton belonging to various groups, namely diatoms (90), dinoflagellates (21), Chlorophyceae (3), Cyanophyceae (2) and silicoflagellates (1) were observed during the study. The species diversity, richness and evenness values varied from 0.7 to 4.2 units/individual, 0.9 to 5.7 and 0.19 to 0.75 respectively. Dominance index values varied between 32.6 and 96.4 during the study period.