bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aspects of the Ecology of the Fishes of Holyrood Pond: A Coastal Lake with Occasional Access to the Sea Located in St. Mary's Bay, Newfoundland
Authors: O'Connell Michael F. , Andrews Cater W. , O'Brien Johannah P. , Dawe Earl G. 
Published: February 2007

AbstractPhysical and chemical conditions and fish were studied during spring and summer in 1974 and 1975 in Holyrood Pond, Avalon Peninsula, Newfoundland. It is a landlocked body of water lying at sea level (length = 21.72 km; maximum width = 1.55 km; maximum depth = 100.0 m) which is occasionally opened to the sea. The landlocked condition is caused by prevailing southwest winds and wave action which create a beach barrier that effectively isolates the mouth from St. Mary's Bay. Under landlocked conditions, there was a continual decrease in salinity and dissolved oxygen at all depths. Temperature profiles were of a dichothermic nature; a certain amount of temporal variability was noted in lower lying water. When the barrier was opened (by bulldozer) and the pond came under tidal influence, there was a replenishment of salt water and dissolved oxygen. Temperature profiles retained the same overall shape but were more erratic, and compared with the closed barrier condition, showed greater variability with time especially in the deeper water.A small amount of commercial fishing is carried out in the pond during both open and closed barrier conditions. A total of 30 species of fish was encountered during the sampling period. Of these, Salvelinus fontinalis, Gadus morhua, Urophycis tenuis, Pseudopleuronectes americanus and Alosa pseudoharengus were studied in detail. Aspects of their biology are compared with other populations and discussed in the context of environmental conditions peculiar to Holyrood Pond.
Interactions between Phytoplankton, Zooplankton, and Fish in the Nutrient Rich Shallow Lake Hjarbæk Fjord, Denmark
Authors: Olrik Kirsten , Lundøer Steen , Rasmussen Knud 
Published: February 2007

AbstractIn the shallow, nutrient‐rich dammed‐up lake Hjarbæk Fjord the balance between phytoplankton, zooplankton, and fish was completely disturbed during the summer period. Extensive growth of small blue‐green algae (Oscillatoria cfr. trichoides, Pseudanabaena galeata) and chlorococcal green algae (Scenedesmus spp., Monoraphidium contortum, Actinastrum hantzschii) induced a pH rise to 10.5 in July. Fish were driven into the rivers, and many that did not escape died. After the fish had disappeared daphniae multiplied explosively and grazed away the major part of the phytoplankton. Ammonia concentrations rose and oxygen concentrations dropped to noxious levels for highly sensitive fish in August–September. Larger phytoplankton species (Aphanizomenon flos‐aquae, Pediastrum boryanum, Pandorina morum, a. o.) were not grazed by the daphniae and gave rise to a maximum of copepods in September. Fish returned to the lake in October, when pH, ammonia, and oxygen levels had normalized.
Space Partitioning within Populations of Sea Anemones (Genus: Anthopleura) in the California Rocky Intertidal Zone
Authors: Russo Anthony R. 
Published: February 2007

AbstractThe spatial patterns of sea anemones (genus: Anthopleura) were analyzed off the rocky intertidal of California. A. elegantissima partitions space in a regular or even pattern and interferes with conspecifics. Its associate A. xanthogrammica shows no signs of interference with conspecifics or congenerics and displays a clumped spatial distribution.
Individual Growth Rate as a Measure of Competitive Advantages in Cladoceran Crustaceans
Authors: Romanovsky Yuri E. 
Published: February 2007

AbstractIntra‐ and interspecific competition for food is one of the main factors governing zooplankton community structure and the evolution of the life history of herbivorous zooplankters. Competitive advantage considered as the ability of a whole population or some developmental stages to survive at low food concentrations is related to individual growth rate rather than to the body size of zooplankters as the “size‐efficiency hypothesis” postulates. The slow‐growing individuals have been shown to have the most competitive advantage. The outcome of competition among cladoceran species in predator‐free waterbodies depends on the trophic status of the latter. In oligo‐trophic and mesotrophic waterbodies, small slow‐growing cladocerans are the superior competitors, while large rapid‐growing species dominate in eutrophic waters and can outcompete the small cladocerans. Small rapid‐growing species, which are poor competitors, can temporarily colonize eutrophic waterbodies. Three main types of cladoceran life history represent the compromises between low population mortality during periods of food depletion and high population natality at the abundance of food.
Blue‐green Dominance in Lakes: The Role and Management Significance of pH and CO2
Authors: Shapiro Joseph 
Published: February 2007

AbstractField and laboratory experiments show that when nutrients (N and P) are added to a mixed population of algae, blue‐greens predominate. However, if CO2 is added also, or if pH is lowered with HCl, greens predominate. The phenomenon is reproducible, and works with most lakes. Although most successful at pH 5.5, the shift to greens can be made to happen at pH values as high as 8.5. Most blue‐greens appear to be susceptible to the shift, and Scenedesmus and Chlorella are the predominant greens resulting. If pH is raised, the shift is reversed. The reason for the shift is not known. It may involve competition by the algae for CO2, but other evidence suggests that the lowered pH stimulates cyanophage production and lysis of the blue‐greens, with release of nutrients which then are used by the greens. Analysis of results of lake circulation data from the literature and from experiments suggests that the algal shifts resulting from circulation may involve the same phenomena. Understanding of these phenomena should lead to predictable use of circulation as a lake‐management tool.
Experimental Lake Fertilization in the Kuokkel Area, Northern Sweden. Phytoplankton Biomass and Algal Composition in Natural and Fertilized Subarctic Lakes
Authors: Holmgren Staffan Knut 
Published: February 2007

AbstractBased on 500 quantitative algal analyses from 1971–1980 the seasonal variations of phytoplankton biomass and species diversity have been evaluated in one natural and three fertilized subarctic lakes. Enrichment with P alone did not cause any biomass increase and inhibited dinoflagellates and Dinobryon. Enrichment with N alone stimulated Uroglena and Gymnodinium and the biomass increased. No species were inhibited. Enrichment with both N and P made the biomass increase 50–60 times and the stimulated genera were: Chlorella, Choricystis, Chromulina, Chrysochromulina, Gymnodinium, Monoraphidium, Ochromonas, Spiniferomonas, Rhodomonas and Uroglena. In all fertilized lakes monocultures of chlorococcal green algae finally developed.
Seasonal Variations in Four Bacterial Size Fractions from a Hypertrophic Pond in Tokyo, Japan
Authors: Konda Toshifumi 
Published: February 2007

AbstractThe planktonic bacterial populations in the surface water of the hypertrophic Himon‐ya Pond were separated into four fractions (>35 μm, 35‐5 μm, 5–1 μm, and <1 μm) by size fractionation of suspended particles in the water. The seasonal variations in bacterial numbers over a two year period differed for each of the four fractions. The bacterial counts in the >35 μm fraction were mainly dependent on the biomass of Microcystis colonies. Their peaks were observed in summer. In the 35‐5 μm and 5–1 μm fractions, several peaks in bacterial numbers were observed, influenced by the quality and quantity of the particles associated with the bacteria. The bacterial counts in the <1 μm fraction contributed a high proportion of the total throughout all seasons except summer.
A New Species of the Chydorus sphaericus Group (Cladocera, Chydoridae) from Western Montana
Authors: Frey David G. 
Published: February 2007

AbstractChydorus biovatus differs from C. sphaericus sens. str. in that the ephippial female carries two resting eggs, for which the brood pouch is expanded dorsally. resulting in a sharp angle in lateral contour near the junction of the head and shell and in the postpore distance being much elongated. The mature male has the pre‐anal angle of the postabdomen rounded and the rostrum broadly rounded, both features being much different than in C. sphaericus sens. str. In North America there is a progressive replacement of C. brevilabris‐group species in the South to C. sphaericus‐group species in the Far North. Production of two resting eggs by Chydorus piger is recorded.
Nutrient Load, Trophic Conditions and Restoration Prospects of Lake Maggiore
Authors: Mosello Rosario , Ruggiu Delio 
Published: February 2007

AbstractThe trophic status of Lake Maggiore is revised following the OECD (1982) approach to eutrophication, using detailed, long‐term data on nutrient sources and loads, and in‐lake nutrient, chlorophyll and phytoplankton conditions as a factual basis. Alternative hypotheses of phosphorus load reduction are considered in the light of partial measures already under way. The need for an integrated, whole‐basin restoration strategy is emphasized.
Experiments on the Respiration and in situ Development of Baltic Herring (Clupea harengus L.) Eggs
Authors: Braum Erich 
Published: February 2007

AbstractA primary blastodise develops 2 hours and 40 minutes after artifical fertilization at 8 0/00 C and 15 0/100 S. The egg then begins embryonic development. When incubated in water with the oxygen concentration reduced to 50 % or 15 % saturation, the oxygen consumption of the eggs decreased to 73 % or 41 % of normal, respectively. For the in situ experiments, eggs and sperm taken from living fishes were spread on plexiglas plates in a way that monolayers adhered to the surface. The plates were then moored to buoys at two depths in a spawning area at Pötenitzer Wiek near Travemünde. Egg mortality increased with the duration of incubation. About 90 % of the spring spawn died before hatching, but only a 10 % mortality occurred among those spawned in autumn. Scanning electron microscope examination revealed structural changes on the egg surfaces caused by bacteria and particles of sediment. The role for survival of the pattern formed by the eggs as they adhere to the surface is discussed.
Observations of the Suspended Matter Distribution Dynamics in the Elbe Estuary from Time Series Aerial Photographs
Authors: Doerffer Roland 
Published: February 2007

AbstractSeries of aerial photographs taken with an interval of 6 Minutes were used to study the dynamics of the suspended matter distribution in a 1 km section of the Elbe Estuary. The observations show heterogeneous distribution patterns which are different at each phase of the tidal cycle. The comparison with the bathymetry indicates that the distribution is mainly a function of the river bed topography, which modifies the local current structure. The surface distribution in the fairway region is especially determined by the ship traffic.
Effects of Entrainment on Phytoplankton Primary Production at Four Thermal Electric Generating Stations on the Laurentian Great Lakes
Authors: Dunstall Thomas G. 
Published: February 2007

AbstractPrimary production was used to measure the response of phytoplankton to entrainment in once‐through cooling water at thermal electric generating stations. Ambient lakewater temperatures ranged from 1.0 to 20.5 °C. The maximum discharge temperature was 32.0 °C. There was no chlorination of cooling water at the stations studied. On a few occasions, primary production was stimulated following station passage by discharge temperatures which were approximately 10 °C above ambient lakewater temperatures of 4.5 to 8.5 °C. Differences in production levels were not apparent, however, following the return of discharge water to ambient lakewater temperature. There was no consistent response of phytoplankton to the temperature regimes tested, with production levels generally differing by less than 20 % as a result of station passage or temperature elevation alone. Entrainment was considered to have minimal impact on phytoplankton productivity in large open water bodies such as the Great Lakes.
Sarsilatona, a New Genus of the Family Sididae (Crustacea, Cladocera) with Two Redescribed Species and One New Species
Authors: Korovchinsky N. M. 
Published: February 2007

AbstractStudies of the type material of two Cladocera species belonging to the Sididae family, Pseudosida papuana Daday 1900 and Latonopsis serricauda Sars 1901, have revealed that they belong to a new genus of the family, Sarsilatona gen. nov. Its members are characterized by a high body and head with an eye located closer to its dorsal side, relatively short antennulae, the presence of hooks on the ends of two setae of the swimming antennae, only small setulae or denticles on the ventral edges of the shell valves, two long unfeathered setae and original clusters of spinules on the posterior edges of the valves, postabdominal claws with three long and thin basal spines and the postabdomen with clusters of anal teeth. These two species are compared with members of their closest genera Latona, Latonopsis, Pseudosida. A detailed redescription and comparison of the structure of Sarsilatona papuana (Daday 1900) comb. nov. and S. serricauda (Sars 1901) comb. nov. from different populations have been made. In the latter species maxillulae, maxillae and trunk limbs have been described. A new species of the indicated genus–Sarsilatona behningi gen. nov. sp. nov.–from a lake in the Amazon River basin in Brazil has been described. The functional and morphological aspects of Sarsilatona structure are discussed.
Environmental Effects on Specific Rate of Photosynthesis in Small Fertilized Lakes (North‐west of the USSR)
Authors: Tereshenkova T. V. 
Published: February 2007

AbstractFrom 1975 to 1981, 136 diurnal values of P/B coefficients for the phytoplankton over the water‐column and 22 seasonal ones were obtained in 8 shallow fertilized lakes. A distinct direct correlation was found between the specific rate of photosynthesis and the temperature during the summer‐autumn season. In spring, the correlation was not so distinct; this period is characterized by higher photosynthetic activity of the phytoplankton due to a number of conditions favouring the development of algae: enrichment of water with nutrients, high daylight factor, and low biomasses in young populations of algae. An inverse correlation was found between the specific rate of photosynthesis and the phytoplankton biomass. The data obtained show that the introduction of nitrogen‐phosphorus fertilizers into the lakes (in the absence of unfavourable factors) greatly increases the daily P/B coefficients. The specific rate of photosynthesis and the morphometry of lakes were found to be correlated directly in small (up to 50 ha) lakes.
The Availability of Phosphorus and the Species Composition of the Spring Phytoplankton in Lake Erken
Authors: Pettersson Kurt 
Published: February 2007

AbstractThe spring development of phytoplankton and the phosphorus content were monitored intensively in Laken Erken during the springs of 1979 and 1980. The dominant species were dinoflagellates, mainly Woloszynskia ordinata and Peridinium aciculiferum, during the entire spring of 1979. The long period of ice‐cover (21 weeks) favoured the motile species, which were able to utilize the available light immediately below the ice. A considerable vertical migration was noticed in March 1979.These large and slow‐growing algae were able to store luxury phosphorus, and surplus phosphorus concentrations up to 12 μg P/l were measured, which corresponded to an algal content of 10 μg P/mg C. These values were more than twice as high as those recorded earlier in Lake Erken. Although a spring outburst of diatoms did not occur in 1979 and 1980, the algae were phosphorus‐limited in May, as indicated by high alkaline phosphatase activity, low algal surplus phosphorus content and high inorganic N : P ratios.
The Epipelic Algal Flora of the River Wye System, Wales, U.K. 1. Productivity and Total Biomass Dynamics
Authors: Antoine Samir E. , Benson‐Evans Kathryn 
Published: February 2007

AbstractThe spatial and temporal fluctuations of the phytopigment content, “potential” primary productivity and total biomass of the epipelic algae of the River Wye System were studied during June 1979 to May 1981. Chlorophyll‐a and productivity values showed a downstream increase, much less obvious for the total biomass. Phaeophytin‐a values followed almost similar spatial and temporal fluctuations to those of chlorophyll‐a. High chlorophyll‐a productivity and total biomass values were recorded during warmer months due to favourable environmental conditions for algal growth, but lower values during unfavourable winter and flood periods.
A Contribution on the Age‐structure of Branchiostoma lanceolatum
Authors: Sager Günther , Gosselck Fritz 
Published: February 2007

AbstractFormer investigations into the age structure of Branchiostoma lanceolatum by Courtney (1975) and Gosselck and Spittler (1979) centered on the assumption that the relative length growth of this species diminishes logarithmically with increasing age. Regarded from a mathematical point of view, this relation demands an exactly channelled form of growth, and this can be checked by submitting the basic values to nonlinear regression. As the results of this procedure yield considerable deviations from the measured data, the function of length growth given by Pütter and v. Bertalanffy is applied and reduces the error by about 70 %. As a consequence the former assumption must be corrected.
A Measure of Plankton Community Similarity Utilizing Variable Weighting of Total Density and Taxonomic Proportionality
Authors: Nicholls K. H. 
Published: February 2007

AbstractFour commonly used formulae for measuring percentage similarity (PS) of biological communities were tested for their usefulness in relating to two plankton community properties, species proportional differences and total density differences. The formula best combining species proportionality and total density in the expression of PS is new:

where min (xi,yi) is the lesser percentage (doubly standardized) of a species in two samples X and Y and where 2 q, 2xi and 2yi are the total quantities of all species in samples 8,X and Y, where \documentclass{article}\pagestyle{empty}\begin{document}$ \sum\limits_i {z_i } ,\,\sum\limits_i {x_i } \,and\sum\limits_i {y_i } $\end{document} are the total quantities of all species in samples Z, X and Y, respectively. Sample 2 contains the highest density of all species in the set; \documentclass{article}\pagestyle{empty}\begin{document}$ \sum\limits_i {z_i \, > \,(\sum\limits_i {x_i ,\,} \sum\limits_i {y_i } )} $\end{document}.The new expression of PS is simple to use and has the additional advantage of offering the analyst an unlimited choice of weighting factors or importance values for proportionality of species content and total density. The method has been applied to data from Gravenhurst Bay (Ontario) and effectively demonstrates the consequences of phosphorus loading reductions for phytoplankton communities.
Comparative Limnology of Several Reservoirs in Central India
Authors: Sankaran Unni K. 
Published: February 2007

AbstractTwenty four reservoirs in Central India were investigated for their physical, chemical and biological features. These reservoirs differed significantly in their size, physical features, chemical composition and vegetation. Three medium and major reservoirs recorded comparatively low electrical conductivity. All the eighteen minor reservoirs showed high conductivity and low transparency since they were all situated in densely populated urban areas polluted by human faeces and domestic sewage. The most abundant ions in water are calcium, carbonate and chloride. The phytoplankton was found to be dominated by Cyanophyceae. Rotifers dominated among zooplankton. All the minor reservoirs are highly eutrophicated. Among the major reservoirs Tawa Reservoir is oligotrophic while others are mesotrophic to eutrophic in nature.
Vertical Migration and Mortality of Marine Benthos in Dredged Material: A Synthesis
Authors: Maurer Don , Keck Richard T. , Tinsman Jeffrey C. , Leathem Wayne A. , Wethe Christian , Lord Charles , Church Thomas M. 
Published: February 2007

AbstractThis account describes the comparative response of four species of benthic invertebrates to burial in terms of vertical migration and mortality, and provides a synthesis of studies and recommendations upon which to assess future impacts. The species featured were the bivalve Mercenaries mercenaria, the amphipod crustacean Parahaustorius longimerus, and the polychaetes Scoloplos fragilis and Nereis succinea.There was evidence of synergistic effects on burrowing activity and mortality with changes in time of burial, sediment depth, sediment type and temperature. In sediment with silt‐clay, N. succinea was the most resistant species followed by M. mercenaria, S. fragilis and P. longimerus. In sediment without silt‐clay the order of percent mortality was reversed.Studies of surface water chemistry and sediment geochemistry showed that dissolved oxygen decreased significantly and ammonia and sulfide increased significantly between the surface and below 2.0 cm within a 15‐day period. Based on these results and physiological tolerances from the literature it was concluded that M. mercenaria and N. succinea would be relatively resistant to chemical effects of spoil disposal, whereas S. fragilis and P. longimerus would be less resistant to such effects.Vertical migration of benthic invertebrates through dredge disposal can be a viable mechanism of recolonization under certain conditions. Some effects of burial of benthos can be predicted based on morphology, behavior and physiology. These biological features were discussed with examples dealing with molluscs, crustaceans, and polychaetes. Finally, recommendations were made concerning the type of studies to provide additional data to aid management agencies in decision making about future dredging and disposal practices.
Variation in Chemical Composition, Reproductive Success and Body Weight of Daphnia magna in Relation to Diet
Authors: Cowgill U. M. , Emmel H. W. , Hopkins D. L. , Takahashi I. T. , Parker W. M. 
Published: February 2007

AbstractThe concern of this study has been the chemical composition of Daphnia magna, the algae (Selenastrum capricornutum, Ankistrodesmus convolutus) it was fed, the two growth media in which the algae were cultured and the water (Lake Huron, Michigan, USA) in which D. magna was reared. A synthetic diet (fish chow + alfalfa) was used as a control. The effectiveness of these five diets on the health of the D. magna populations was ascertained by the weight and number of neonates thus produced. The diet, S. capricornutum cultured in an organic medium, produced the largest mean brood size and the heaviest neonates in unstressed populations. The synthetic diet produced the smallest mean brood size and the lightest neonates. Stressed organisms may produce smaller broods with heavier neonates than unstressed organisms. The evolutionary significance of this observation is discussed. Statistical studies suggest that daphnids maintained on the synthetic diet derived no demonstrable nutritive value from the diet in terms of elemental composition or amino acid production. A great similarity in patterns of amino acid quantity and type was noted in the algae and the daphnids. On further examination it was discovered that this pattern was widespread in other aquatic forms, bacteria, fungi, yeasts, casein and was common to a variety of birds and mammals. It may be suggested that products that are made and stored, such as lipids, are less uniform in pattern among widely diverse species than those that have to be produced and are not stored, such as amino acids.