bluuebunny/crossref_metadata_2025 huggingface dataset:
The relation of incident radiation to diurnal rates of photosynthesis in lough neagh
Authors: Jewson D. H.
Published: February 2007

The homogeneous nature of the water column in L. Neagh enabled the testing of a semi‐empirical model for calculating the integral gross photosynthesis with respect to depth and time. In particular a logarithmic function describing the photosynthetically available radiation was examined, as the other major determinants in the model remained relatively constant, during a diurnal study on 3. 6. 70. Agreement between planimetric and calculated rates of integral gross photosynthesis for both instantaneous and daily periods is comparable with the performance of more complex models; however the problem of measuring net yields of ‘column’ photosynthesis remain.
Typologie de bactéries prélevées devant le delta du Rhöne. Classification hiérarchique par une méthode d'agrégation suivant la variance. Clustering of Bacteria Isolated Seaward from the Rhǒne Outlet. Hierarchical Classification Using the Method of Aggregation According to Variance
Authors: Berland B. R. , Bonin D. J. , Maestrini S. Y. , Durbec J.‐P.
Published: February 2007

Bacteria isolated from surface sea waters, brackish waters and from algal cultures were studied to attempt a nutritional clustering. A hierarchical method, using aggregation according to variance, was used to compute the data. Six nutritional groups had been separated by differences in genus composition and nutritional characteristics. Groups range from one with bacteria which are poorly versatile, i.e. attach few different substances, and which grow on sugars, amino‐acids and organic acids without any selectivity, to one with bacteria which are versatile, and which attack numerous organic acids and amino‐acids, but only a few sugars. Bacteria from different origins are not spread randomly in the different clusters. Strains isolated from algal cultures are mainly associated with the lowest versatility; those isolated from the undiluted sea water are associated with the highest versatility. Bacteria from diluted sea waters appear to be intermediate in regard to their capability of using organic substances as their sole source of carbon. It also appears that organic acids provide individually the most discriminating substrates, i.e. the most useful for separating individual groups, but amino‐acids and organic acids, as a whole, are not easy to use in classification, because they are too heterogeneous. Sugar contribution to classification is almost nil.
Variabilité à court terme des propriétés physiques, chimiques et biologiques du Saguenay, fjord subarctique du Quebec (Canada)
Authors: Cǒté Raynald , Lacroix Guy
Published: February 2007

Tidal variability of water mass characteristics has been assessed in the upper 100 metres of the Saguenay, a subarctic fjord in Québec, Canada. Temperature and salinity show a maximum variability in the 5‐15 m layer in which vertical oscillations of a very sharp pycnocline are observed. Phosphates, nitrates and chlorophyllaare highly variable above this pycnocline during a tidal cycle, but dissolved oxygen content is remarkably stable in the whole water column. It is concluded that fluctuations of many variables in the subsurface waters might be large enough to hinder high rates of primary production.
The Saline Lakes of Saskatchewan IV. Primary Production by Phytoplankton in Selected Saline Ecosystems
Authors: Haynes Robert C. , Hammer U. Theodore
Published: February 2007

Primary production by phytoplankton, efficiency of photosynthesis, and chlorophyll‐a concentrations were determined for seven saline lakes that varied widely in ionic concentration and composition. The investigations were done during the summer months of 1972 and 1973. Productivity ranged from 0.001 to 11.135 g C m−3 day−1 and 0.053 to 7.968 g C m−2 day−1. Highest productivities were measured in two lakes that supported blooms of Aphanizomenon flos‐aquae and Nodularia spumigena, respectively. Species of Cyanophyceae, Bacillariophyceae and Chlorophyceae dominated the phytoplankton of the study lakes. Active chlorophyll‐a ranged from 0.01 to 116 mg m−3. Integral photosynthetic efficiency estimates were <1% except during phytoplankton blooms when they were considerably higher. The overall range of 0.03 to 3.8% is concordant with estimates for other lacustrine ecosystems. The extinction of light caused by photo‐synthetic processes, or in situ efficiency, was <1% in the trophogenic zone for most lakes but, it was considerably higher during blooms. In situ efficiencies invariably increased with depth in ail lakes.
Man‐made Changes in Some Dutch Moorland Pools, as Reflected by Historical and Recent Data about Diatoms and Macrophytes
Authors: van Dam Herman , Blokland Hannie Kooyman‐Van
Published: February 2007

The diatoms of plankton samples taken between 1916 and 1929 and in 1975 from shallow pools, which were originally oligotrophic, are compared. Data about the past and present distribution of macrophytes were gathered from the literature and by field studies. Eutrophication caused by agriculture and recreation, and acidification from precipitation led to important changes in the biocenoses of the moorland pools during the last fifty years.
Discharge Measurement in Lower Order Streams
Authors: John Peter H.
Published: February 2007

A large number of conventional and less conventional discharge measuring techniques applicable to lower order streams are discussed. The intention is to provide aquatic biologists and water chemists with sufficient alternative methods so that a suitable choice may be made based on factors such as stream characteristics, required accuracy and available funding and man‐power. In each case the method is described, details of design and use outlined, and areas of application and possible deficiency noted. In addition the criteria determining method selection are discussed.
Ökologische und systematische Studien über das Neuston alpiner Kleingewässer, mit besonderer Berücksichtigung der Ciliaten.
Authors: Foissner Wilhelm
Published: February 2007

Ecological and Systematic Studies on the Neuston of Alpine Pools, with Special Regard to Ciliated Protozoa

The qualitative and quantitative composition of the neuston of 31 alpine pools with different degrees of organic pollution was investigated. Phytoflagellata and Ciliophora dominated in highly eutrophic pools, Phycomycetes in less eutrophic ones. The light‐dependent migration of the photoautotrophic heloneuston from the plankton to the surface film caused a strong depression of the neustonic Phycomycetes. Ciliates specially adapted to a neustonic mode of life were not found. The morphology, infraciliature, silverline system and ecology of nine species occuring more frequently in the hyponeuston were studied. A new species (Kreyella minuta)., a new genus (Pseudochilodonopsis). and a new family (Kreyellidae). are described. Some problems dealing with the ecology of ciliates in the surface films of natural pools and of enrichment cultures are discussed.
Intertidal Benthic Invertebrates and Sediment Stability at the Mouth of Delaware Bay
Authors: Maurer Don , Aprill Glenn
Published: February 2007

From December 1970 to December 1972, the monthly species composition, density, species richness, and biomass of marine macroscopic invertebrates were quantitatively studied from a wave‐protected, intertidal sand flat at the mouth of Delaware Bay. Considerable erosion, transportation, and deposition of sand occurred throughout the study period. The fauna was extremely flexible and resilient in its response to a gradient of considerable sediment mobility. This response was similar in scope to one recognized along the coast of California. Comparison of the local biota with other sand flats and beaches from Maine to South Carolina showed that (1). haustoriids were among the dominant species, (2). densities were roughly comparable, and (3). secondary species were similar.

Based on the biological index value, three species contained 87.8% of the fauna from the Cape Henlopen tide flat. These species were the polychaete Scoloplos fragilis and the amphipod Neohaustorius biarticulatus, which were characteristic of sand bars, and the polychaete Heteromastus filiformis, which was more characteristic of troughs or depressions. Mean density varied considerably both monthly and annually with almost no cyclic repetition for any of the three species. There was evidence to indicate that specific habitat requirements of a few species can strongly affect the structure which emerges for a total fauna. Morphology, behavior, physiology, and reproductive strategy are aspects of biology which link dominant benthic species of intertidal sand beaches together.
Algological Investigations in the Polluted Ashar Canal and Shatt al‐Arab in Basrah (Iraq)
Authors: Al‐Saadi H. A. , Pankow H. , Huq M. F.
Published: February 2007

In the Ashar Canal in the city of Basrah and in the Shatt al‐Arab directly below the mouth of the Ashar Canal algological and saprobiological investigations were carried out. The water of the Ashar Canal is β‐ to α‐mesosaprobic, the water of the Shatt al‐Arab below the mouth of the Ashar Canal is β‐mesosaprobic.
Age Structure, Growth, and Weight of Branchiostoma senegalense (Acrania, Branchiostomidae). off North‐West Africa
Authors: Gosselck Fritz , Spittler Peter
Published: February 2007

Branchiostoma senegalense from a population off North‐West Africa reach an age of 4–5 years. Relative growth decreases logarithmically with age. B. senegalense reaches 50% of its maximum length during the first year. Differences in the average length of these lancelets in samples taken in close proximity of each other are ascribed to the absence of individual year classes. The immigration of larvae into suitable sediments depends on the current and follows the pattern of the larval swarms in the plankton. Colonized areas are not normally left.

The functions relating wet and dry weights (WW and DW respectively). to length L are lg WW = 2.71 × lg L – 2.16, and lg DW = 2.96 × lg L – 3.45. The dry weight is 11.85% of the wet weight.
Hydrobiological Outline of the Mongolian Lakes
Authors: Dulma A.
Published: February 2007

The waters of Mongolia can be classified according to their catchment areas into three hydro‐geographic regions: basin of the Arctic Ocean, basin of the Pacific Ocean, Central Asian basin without outlet. After a short historical survey of the exploration of the lakes of the Mongolian People's Republic, the formation and the classification of the lake system is briefly dealt with. Recent hydrobiological findings are presented in addition to hydrological data. As far as possible, statements are made on the size and the depth of the waters, the growth of macrophytes and the trophic level of the lakes. A distinction is made between ultraoligotrophic, oligotrophic, mesotrophic, eutrophic and dystrophic waters. They are characterized by data on the biomass of the plankton and the ichthyofauna. In the zooplankton of the Central Asian basin, 17 copepod, 29 cladoceran and 58 rotatorian species, and in the waters belonging to the drainage basin of the Pacific Ocean 16 copepod, 40 cladoceran and 37 rotatorian species have already been identified.

The results represent the basis for an intensification of fishery in the Mongolian People's Republic.
Chemical and Mineralogical Composition of the Mud‐Water Interface of the Lake Huleh (Israel) Preserve
Authors: Cowgill Ursula M.
Published: February 2007

There is scant information about the chemical composition of the mud‐water interface in shallow, aerobic, eutrophic bodies of water. This study is concerned with the chemical and mineralogical composition of the mud‐water interface of the Lake Huleh preserve (Israel). The most important conclusion gleaned from this investigation is that elements preferentially sorbed by the mud from the mud‐water interface in shallow, aerobic aquatic systems such as the Huleh preserve do so by two methods: organic matter sorption (cadmium, bromine) and scavenger action of ferric hydroxide (cesium, beryllium, mercury, tin, titanium, zirconium, bismuth, vanadium, molybdenum and iodine) type complexes. Forty‐six elements were detected in the mud‐water interface; their behavior in this system is described.
Desmids of Bangladesh
Authors: Islam A. K. M. Nurul , Haroon A. K. Yusuf
Published: February 2007

214 taxa under 21 genera of desmids have been described and illustrated from Bangladesh, of which 3 species and 8 varieties are new to science.
Possible Reason for the Expansion of Carassius auratus (Linnaeus, 1758) (Teleostei, Cyprinidae) in the Danube River Basin
Authors: Hholčík Juraj
Published: February 2007

The author found quite a close negative relationship between commercial catches of predatory fishes and of German carp (Carassius auratus) in the lower Danube. He supposes that the main reason for the population explosion and subsequent expansion of German carp in the Danube River basin seems to be a shift in the balance of the fish community due to a reduction in the density of predatory species.
Physical and Chemical Studies of Lago Tupé; a Central Amazonian Black Water “Ria Lake”
Authors: Rai Hakumat , Hill Gary
Published: February 2007

Lago Tupé, a Central Amazonian dystrophic black water “Ria lake” (blocked valley lake), lateral to the Rio Negro, was studied at all depths for a year. Physical and chemical results of that study are presented here as a prelude to the microbiological studies. The lake's origin and morphology are discussed. Results concerned with thermal properties, suspended matter and dissolved solids are presented, in addition to results on ionic composition, alkalinity, hardness, pH and dissolved oxygen. Nutrient studies include section of phosphate and nitrogen and conclude with silicate results.
Freshwater Ostracods (Crustacea: Ostracoda) of the GenusCyprettaVAVRA, 1895 from Malaysia, Indonesia and the Philippines
Authors: Victor Reginald , Fernando C. H.
Published: February 2007

The genusCyprettaVAVRA, 1895 from Malaysia, Indonesia and the Philippines is reviewed. Currently, eleven species are known from these areas. Two new species are described and two species are redescribed. Remarks and diagnostic illustrations are given for the known species.
Silica Budgets and the Ecology of Planktonic Diatoms in an Unstratified Lake (Lough Neagh, N. Ireland)
Authors: Gibson C. E.
Published: February 2007

River inputs of dissolved silica into a shallow eutrophic lake (Lough Neagh, N Ireland) are quantified. Exports of silica are high (3.6 to 9.6 tonnes dissolved SiO2 km−2y−1), but the spring concentration of dissolved silica in the lake depends on release of silica from the sediments. Two planktonic diatoms Melosira italica subarctica O. MÜLL, and Stephanodiscus astraea (EHR.) GRUN. dominate the spring flora. Their periodicity is described over ten years and their usage of silica and phosphorus is examined. Data are presented on the resuspension of cells from the sediment, the growth rates of the diatoms in the lake, the incidence of parasites and changes in the filament length of M. italica subarctica.
Primary Productivity of Phytoplankton, Environmental Covariates and Fish Growth in West Bengal Ponds under a Polyculture System
Authors: Jana B. B. , De U. K.
Published: February 2007

Measurements of primary production by phytoplankton in four fish ponds over a period of one year revealed a distinct spatial variation in rate. The ponds were used for polyculture, monoculture, or a traditional system of fish culture. The rates of gross photosynthesis were highly correlated with temperature, free CO2, oxygen, inorganic nitrogen (NH4+, NO2−, and NO3−) and PO4‐P. It was shown by step‐wise multiple regression analysis that in the polyculture pond with a predominantly autotrophic metabolism, gross photosynthesis was the most significant factor correlated with fish growth. In another polyculture system in which the metabolism was mainly hetero‐trophic, the influence of the photosynthesis rate was slight.
Mathematical Investigations into the Longevity of the Ocean Quahog Arctica islandica (Mollusca: Bivalvia)
Authors: Sager Günther , Sammler Rudolf
Published: February 2007

Annual internal growth banding of Arctica islandica has shown that the species has a surprising longevity of up to 149 years as stated by THOMPSON, JONES and DREIBELBIS (1980). The authors have compiled 100 values of valve height against age as reproduced in Figure 1. Visually gained growth curves have been added for single specimens that leave some doubt as to the existence of an inflexion point. In this paper a cross‐sectional evaluation of growth behaviour is carried out with nine funtions using nonlinear regressions. Five growth functions yield almost equally good results with a final valve height just below 100 mm. An inflexion point is either present in early youth or lacking altogether, depending on the growth function used.
Growth Kinetics of Microcystis aeruginosa (KÜTZ) KÜTZ as a Basis for Modelling its Population Dynamics
Authors: Nicklisch Andreas , Kohl Johannes‐Günter
Published: February 2007

The dependence of the specific growth rate of Microcystis aeruginosa (KÜTZ); KÜTZ f. aeruginosa upon temperature and light intensity was determined under continuous illumination in batch cultures. The result can be well described by the function:magnified image where μmax = 3.44.d−1, Topt = 33.2°C, Tmin = 18.3°C and KI = 71.4 Wm−2. The validity of this function is limited to the range of 10–28 °C and light intensities from 5–25 Wm−2. The dependence of the specific growth rate on the nutrient concentration was investigated a t 25°C and 24 Wm−2 light intensity by means of chemostat cultures. The half saturation constants related to the maximum specific growth rate of 1.1 d−1 measured under these conditions were 0.44 μmol.I−1, 4.3 μmol.I−1 and 26.5 μmol.−1 for orthophosphate, nitrate, and ammonium, respectively.
Distribution and Abundance of Zooplankton in an Alkaline Freshwater Marsh in Northumberland County, Pennsylvania
Authors: Seelbach Paul W. , McDiffett Wayne F.
Published: February 2007

The zooplankton community of two ponds in an alkaline marsh in central Pennsylvania were studied. The ponds were found to be distinctly different from one another with regard to species but similar when only zooplankton types are considered. The ponds were quite similar with respect to a number of physico‐chemical characteristics but differed significantly with respect to alkalinity, conductivity, habitat type, vegetation, depth, and predation pressure.
Effect of Filter‐feeding Zooplankton on Phytoplankton in Fish Ponds
Authors: Vyhnálek Vojtêch
Published: February 2007

The effect of filter‐feeding zooplankton on phytoplankton was investigated in two fish ponds near Blatná (southwestern Bohemia, Czechoslovakia) using enclosures of 50 liters volume. Filter‐feeding activity had a positive effect on the growth of individual net phytoplankton (> 40 μm) species except for Aphanizomenon flos‐aquae and Melosira granulata. Except for Schroederia setigera nanoplankton species (< 40 μm) were suppressed by the filter‐feeding zooplankton. In bags without zooplankton the addition of nutrients induced growth of nanophytoplankton species, but no significant differences were noted in bags with zooplankton.
Seasonality and Structure of a Macrobenthic Seagrass Community on the Florida Gulf Coast
Authors: Bloom Stephen A.
Published: February 2007

Macrofauna at two intertidal sites, quantitatively sampled monthly for 25 months, exhibited distinct reoccurring population fluctuations which were poorly correlated with abiotic parameters. Faunal dominants, Laeonereis culveri and Onuphis simoni, showed reciprocal fluctuations. Laeonereis exhibited non‐synchronized reproduction and recruitment while Onuphis exhibited synchronized release. Laeonereis peaked before Onuphis while Oniphis fluctuated with the majority of other species. The faunal dominants exhibited one cycle in autumn at both sites but also exhibited a cycle at only one site in spring. Temperature is thus not indicated as causal and detrital input was suggested as the overriding factor. A hypothesis was advanced that Laeonereis is an opportunistic species exploiting fresh detritus, while Onuphis is a detritus feeder utilizing bacterial populations.
Ammonia Excretion in Snails Viviparus bengalensis (LAMARCK) and Pila globosa (SWAINSON) during Active and Dormant Periods
Authors: Chaturvedi M. L. , Agarwal R. A.
Published: February 2007

The quantities of ammonia excreted over a period of 24 h by two prosobranch snails Viviparus bengalensis and Pila globosa were measured at 30 day intervals to compare their excretion during the active and dormant phases of their life. The aquatic snail V. bengalensis excreted 0.5‐1.0 μmole of ammonia per day and snail throughout the year. The ammonia excretion rate of this snail was 40‐50% lower in winter than in the monsoon and summer period. In the amphibious snail Pila globosa excretion of ammonia was limited to only four months of its active life i. e. during July‐October. Also the rate of ammonia excretion in P. globosa (0.2‐0.3 μmole per day and snail) was very low compared with V. bengalensis.
Macrobenthic Communities of the Lower Chesapeake Bay. IV. Bay‐wide Transects and the Inner Continental Shelf Benthic Studies of the Lower Chesapeake Bay 7
Authors: Dauer Daniel M. , Stokes Thomas L. , Barker Howard R. , Ewing R. Michael , Sourbeer Jerry W.
Published: February 2007

The distribution, abundance, and species composition of subtidal macrobenthic invertebrates of the lower Chesapeake Bay and the inner continental shelf off the mouth of the bay were studied. The benthos of the lower bay was sampled on two bay‐wide transects sampled once in June 1978. The benthos of the inner shelf was sampled five times per year from 1979 through 1981. Data from this study were compared with data from previous studies of estuaries and the inner shelf of the mid‐Atlantic Southeastern U.S.
Integrated Samples Provide Accurate Means of Parameters Characterizing Aquatic Ecosystems
Authors: Vietinghoff Ulrich , Erdmann Norbert , Arndt Hartmut , Kell Volkbert , Hubert Marie‐Luise
Published: February 2007

The measurement of ecosystem parameters normally involves considerable effort in terms of sampling and analysis due to their variation in time and space. This contribution describes the advantages and properties of the integrated sample and demonstrates them by comparing the statistical properties of separate samples (number of Filinia longiseta per unit volume), and integrated sample (total chlorophyll a concentration) and phytoplankton samples analyzed by the Utermöhl method. A working hypothesis is presented to explain the causes of the overdispersion that hinders phytoplankton analysis and to suggest ways of eliminating it.
Metabolic Heat Flow Patterns in the Intertidal Mussel Ischadium ( = Modiolus=Geukensia) demissum demissum during Aerial and Underwater Respiration
Authors: Pamatmat Mario M.
Published: February 2007

Rapid changes in heat production rate by Ischadium demissum demissum (=Modiolus demissus demissus, Geukensia demissa), largely though not exclusively effected by opening and closing of shell valves, signify changing metabolic states, physical activity level, and body processes with time and experimental condition. It is theorized that the relative rates of anaerobic metabolism and oxygen uptake, as influenced by temperature, and the presence or absence of unfavorable external stimuli all interact, in feedback mode, to regulate the opening and closing of shell valves. Knowledge of the pattern of instantaneous changes in metabolic rates of organisms is essential in analysis of, and interpreting and comparing data on, average metabolic rates. Direct calorimetry should be particularly useful in understanding the evolutionary ecology of facultatively anaerobic organisms.
Seasonal Physical, Chemical and Algal Changes in Five Rivers Flowing Through the Oil Sands Region of Alberta, Canada
Authors: Charlton Shirley E. D. , Hickman Michael
Published: February 2007

Seasonal studies concentrating upon physical and chemical parameters and the epilithic algal community were conducted at specific sites in five tributary rivers flowing through the oil sands region of northeastern Alberta, Canada into the Athabasca River. Numerically cyanophycean algae (Lyngbya aerugineo‐caerulea, Phormidium sp., Calothrix braunii, Nostoc spp. and Anabaena affinis) dominated followed by diatoms (Achnanthes lanceolata, Cocconeis pediculus, Cocconeis placentula, Epithemia sorex, Epithemia turgida, Gomphonema acuminatum, Gomphonema longiceps v. subclavata, Gomphonema olivaceum, Nitzschia fonticola, Nitzschia palea, Synedra rumpens, and Synedra ulna). One exception was the Hangingstone River where chlorophycean algae (Stigeoclonium pachydermum and Cladophora glomerata) were next in importance to the cyanophytes. Seasonal fluctuations in algal species and numbers were influenced by a myriad of interacting parameters. Physically disruptive forces (current velocity and discharge) appeared more important than dissolved nutrients. They were also responsible for affecting the chemical composition of the water itself.
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

Physical 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

In 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

The 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

Intra‐ 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

Field 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

Based 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

The 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

Chydorus 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

The 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

A 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

Series 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

Primary 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

Studies 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

From 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

The 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

The 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

Former 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

Four 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

Twenty 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

This 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.