bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations on the Diet of Some Slope Dwelling Fishes of Southern Portugal
Authors: Saldanha Luiz , Almeida Armando J. , Andrade Francisco , Guerreiro José 
Published: February 2007

AbstractThe diets of 33 fish species from the southern Portuguese slope, at depths between 498 and 740 m were studied through the examination of stomach contents. Species of scyliorhinids, squalids, rajids, chimaerids, anguilliforms, notacanthids, macrourids, gadids and merluccids, with pelagic, benthope‐lagic and benthic modes of life were examined. Nezumia sclerorhynchus feeding habits were studied in detail. Its diet its dominated by amphipods. No differences of prey preferences were recorded corresponding to predator size classes. The studied predators can exploit a wide range of prey, but they feed mainly on benthopelagic and epibenthic material. Consequently it is difficult to establish distinct feeding guilds, so confirming a generalist type of feeding for most of the upper slope dwelling fishes.
Biogenic Sediment Compounds in Relation to Marine Meiofaunal Abundances
Authors: Soltwedel Thomas , Thiel Hjalmar 
Published: February 2007

AbstractCorrelations between a series of biogenic sediment compounds, commonly used in ecological studies, and a major component of the benthic infauna, the meiofauna, were studied on the continental margin off Southwest Africa (Angola) and in a central oceanic region of the Atlantic Ocean (Mid Oceanic Ridge). Biogenic sediment compounds chosen for this investigation (electron‐transport‐system activity, total adenylates and energy charge, particulate proteins, chloroplastic pigments) are obviously not suitable for a quick and rough estimation of meiofaunal abundances. Nevertheless, biogenic sediment compounds might reflect quite well the activity and biomass of the total benthic infauna, including all size classes (from bacteria to macrofaunal organisms) and/or the total particulate organic matter within the sediments. Furthermore, analyzing biogenic sediment compounds leads to a better understanding of environmental conditions and biological activities of benthic organisms. Consequently, despite their limitations, biochemical sediment parameters may be very useful in benthic ecological studies to obtain rapid information on the eco‐status of the benthic system.
Comparison of the Vertical Distribution of Nematodes from Two Contrasting Abyssal Sites in the Northeast Atlantic Subject to Different Seasonal Inputs of Phytodetritus
Authors: Lambshead P. John D. , Ferrero Timothy J. , Wollf George A. 
Published: February 2007

AbstractThe vertical distribution of nematodes in the sediments of three cores from the phytodetritus‐influenced Porcupine Abyssal Plain station is compared with three cores from the Madeira Abyssal Plain station in the DEEPSEAS programme. Nematode vertical distributions are compared with sediment organic chemistry data sampled at the same time from the same sites. The results support the two hypotheses erected by Thiel (1983) that the penetration of meiofauna into deep‐sea sediments might be correlated with the input of organic matter and that a greater biological activity of larger organisms would increase the penetration of nematodes into the sediment through increase downward transport of food material.
Extraction of Prokaryotic Genomic DNA from Marine Microbial Communities Suitable for Amplification Using the Polymerase Chain Reaction
Authors: McInerney James O. , Paskins Lynn , Eardly Donal , Patching John W. , Powell Richard 
Published: February 2007

AbstractWe present a method for extraction of DNA from marine microbial communities and amplification of the small subunit ribosomal RNA gene from the prokaryotic organisms contained therein. Results of cloning, sequencing and phylogenetic analyses are also presented. This DNA extraction technique is specifically designed to be used in conjunction with the Polymerase Chain Reaction (PCR). Emphasis was placed on producing a technique which results in total cell lysis yielding DNA of sufficient purity to facilitate amplification using PCR. Minimisation of surface contamination and procedure suitability for a multi‐sample study were considered to be of prime importance throughout this investigation. As a demonstration of the suitability of the technique, a preliminary analysis of the small subunit ribosomal RNA (SSU rRNA) gene from marine microbial communities was investigated. The amplification reactions are designed to specifically target the SSU rRNA gene from the two primary prokaryotic domains: Bacteria and Archaea sensu Woese (Woese et al., 1990). The primers were designed to amplify a sequence exceeding 1 Kb in length which is sufficient for use in taxonomic and phylogenetic analyses of marine communities (Murray and Schleifer, 1994). The samples used represent spatially and temporally distinct regimes, from the North East Atlantic. These include water samples from open ocean sites and gut contents from a deep sea deposit feeder, Oneirophanta mutabilis (Holothuria: Elasipodida). The analysis shows the identification of a group of unusual Archaea. as‐yet uncultured, in the samples analysed.
Brachionus calyciflorus Pallas (Rotatoria) in Inland Waters of Tropical Latitudes Brachionus calyciflorus Tropical in Waters
Authors: Kutikova L. A. , Fernando C. H. 
Published: February 2007

AbstractThe widely distributed Brachionus calyciflorus was studied for morphological variation based on material from all tropical areas. The subspecies B. calyciflorus borgerti Apstein is redescribed and its subspecific status affirmed. Various forms with local distributions were noted and described and the morphological differences are attributed to a variety of possible factors. From the distribution patterns it is clear that rotifers are governed by the general principles that apply to other invertebrates and are not cosmopolitan. There are evidently dispersal centres for Brachionus calyciflorus and its subspecies borgerti.
Habitats and Distribution Patterns of Marine Luminous Bacteria in the Western Baltic Sea
Authors: Schulz Claus‐Jürgen , Rheinheimer Gerhard 
Published: February 2007

AbstractNumbers of luminous bacteria were counted at three stations of the brackish water ecosystem of the western Baltic Sea from July 1985 to July 1986. Additional samples were taken during three cruises from stations at the North Atlantic Ocean, the Norwegian Sea and adjacent marine areas. — In Kiel Bight (western Baltic) values varied between 0 and 68,000 luminous cfu 1−1. With exception of the coastal station a distinct seasonal distribution pattern was shown in a water depth of 20 m: high numbers found in summer were opposed to low numbers in winter, the peaks being rather high in comparison to those of other areas. Statistical analysis showed that the results of 20 m were significantly different from those of 0 and 10 m depth; however, there was no correlation with temperature and salinity. Taxonomic studies revealed that the population consisted primarily of the genus Photobacterium. — The optimum of salinity was not a brackish but a marine one and was about 30% for the majority of the strains tested. A smaller number of strains grew best at a salinity between 10 and 15%. Optima of temperature ranged from 15 to 20 °C for most of the test strains. — Taxonomic analysis was also performed with luminous strains from marine areas adjacent to the western Baltic Sea, Photobacterium being the dominant genus here, too. Luminous bacteria were also enriched from the external surface and the gut contents of whitings (Merlangius merlangus) and cods (Gadus morhua). A model is proposed which explains the distribution pattern found. According to this, the gut‐dwelling luminous bacteria are transported by their hosts from the North Sea into the western Baltic Sea. Here they are released into the environment, thus inhabiting another niche.
Defensive Reactions of Stream Ecosystems in the Early Stages of Pollution. Ecological Importance and Possibilities of Ecosystem‐Adequate Restoration Methods
Authors: Schönborn Wilfried 
Published: February 2007

AbstractDefensive reactions of rhithron and epipotamon against low and early organic pollution are described. Hitherto two reactions could be found in streams: transformation of the epilithic energy flow to intensify microbial decomposition, and the mass production of Cladophora for elimination of biomass, nutrients, heavy metals and other noxious agents. The Cladophora production reaction leads to a centralization of the ecosystem, but functions incompletely. This can be compensated by an ecosystem‐adequate restoration method. Similarly the “whiting” (i.e. biogenic decalcification) during in pelagials Cladophora mass production happens at the expense of the benthic communities and may be called “dysoecism”.
The Seasonal Succession of Biotic Communities in Wetlands of the Tropical Wet‐and‐Dry Climatic Zone: III. The Algal Communities in the Pantanal of Mato Grosso, Brazil, with a Comprehensive List of the Known Species and Revision of two Desmid Taxa
Authors: De‐Lamonica‐Freire Ermelinda Maria , Heckman Charles W. 
Published: February 2007

AbstractStudies conducted over a period of about 14 years in the northern part of the Pantanal of Mato Grosso revealed that there is a pronounced seasonal succession of algal communities resulting from periodic flooding and desiccation. Generally, during the high water period, the microflora is very sparse but species‐rich and dominated by the Desmidiales, which are notably inhabitants of mineral‐poor waters. During the dry season, the rapidly evaporating pools of water in the Pantanal often support extremely large concentrations of algae belonging mainly to other orders of Chlorophyta and to Euglenophyta. The seasons of rising and falling water levels are characterized by a mixed flora containing elements typical of both the high water and dry seasons, according to the local conditions that prevail. Dense beds of filamentous algae in the family Zygnemataceae are generally encountered only where there is inflow of nutrient‐rich water or another source of local eutrophication. The algae present belong overwhelmingly to cosmopolitan or circumtropical species. Their presence and relative abundance seem to be determined primarily by the concentrations of inorganic nutrients in the water. Of the 337 species observed, most are reported for the first time from the Pantanal, and the list of species provides the only comprehensive catalog of autotrophic microorganisms yet compiled for this vast wetland. The physical and chemical characteristics of the habitats in which the various algae occur and their relationships with the macrophyte communities are discussed. One variety of desmid is redescribed and given a valid name: Staurodesmus convergens (Ehrenberg ex Ralfs) Lillieroth var. teilingii DE‐Lamonica‐Freire nom. nov., and the taxonomic status of Cosmarium galiciense (Gutwinski) DE‐Lamonica‐Freire comb. nov. is revised.
Modelling of the Genetic Composition of Water Masses in Two Valley Reservoirs in the Volga Basin
Authors: Yershova M. G. 
Published: February 2007

AbstractThe theoretical basis, assumptions and algorithms of the one‐dimensional model CWMVR (Composition of Water Masses in Valley Reservoirs) are given. This model is intended for a diagnosis and forecast of the genetic composition of the river water masses and the main water mass of a reservoir in different seasons of wet or dry years. The results of the calculations of the water masses regime in the Mozhayskoye and Cheboksarskoye reservoirs are given using the hydrometric and chemical investigation in 1984. The errors of the model are estimated by comparison of the computed and measured values of conservative parameters of water quality in the quasi‐synchronous surveys of these reservoirs in 1972 and in 1983‐1985. A satisfactory graphical and statistical similarity (0.55 ≤ S/σ ≤ 0.66) among them is shown. The reasons of the largest errors of modelling and the ways of development of this model are discussed.
Taxonomic Characterization of Pseudohaplocaulus infravacuolatus nov. spec. and Vorticella chlorellata Stiller 1940, Epiplanktonic Peritrichs (Ciliophora, Peritrichia) Attached to Coenobia of Anabaena (Cyanophyta), Including a Redescription of V chlorostigma (Ehrenberg, 1831)
Authors: Foissner Wilhelm , Brozek Susanne 
Published: February 2007

AbstractPseudohaplocaulus infravacuolatus nov. spec. and Vorticella chlorellata Stiller, 1940. two peritrich ciliates attached to planktonic coenobia of Anabaena sp. (Cyanophyta). were investigated using live observation, silver impregnation, and scanning electron microscopy. Pseudohaplocaulus infravacuolatus differs from its nearest relative, P. anabaenae (Stiller, 1940). mainly by the location of the anterior contractile vacuole. Vorticella chlorellata has symbiotic green algae. a J‐shaped macronucleus. and a single, ventral contractile vacuole. The number of silverlines is very close to that of V. picta, but distinctly different from that of V. chlorostigma (Ehrenberg, 1931), an other green Vorticella, redescribed for the first time. Vorticella rhabdostyloides Kellicott, 1885 is recognized as a distinct species, but transferred to Haplocaulus: H. rhabdostyloides (Kellicott, 1885) nov. comb. Likewise, Vorticella fasciculuta Müller, 1773 is considered a distinct species and transferred to Pseudovorticella: P.fasciculata (Müller, 1773) nov. comb.
Hyphomycetes in Twenty Springs of the Knyszyn‐Bialystok Forest in Various Seasons
Authors: Czeczuga Bazyli , Orlowska Miroslawa 
Published: February 2007

AbstractThe aquatic mycoflora and environmental factors in 20 springs were analysed at monthly intervals for one year. At total of 102 Hyphomycete species was noted. 16 species are new records for Poland. The highest number of species was found in spring and autumn. the lowest number in winter.
Measuring drift during a receding flood: Results from an Austrian Mountain Brook (Ritrodat‐Lunz)
Authors: Tockner K. , Waringer J. A. 
Published: February 2007

AbstractThe drift of organisms and large particulate organic matter >200 μm (LPOM) was investigated during a single receding flood event from 16 to 23 June 1989 in a second order, calcareous, alpine, gravel brook. Starting with the peak level of the hydrograph, which was well above bankfull level, sampling lasted for five days (= 8 sampling dates). Between four and eight replicates were taken at each sampling date.No significant differences (P < 0.05) could be detected in the proportion of the main aquatic taxa (excluding miscellaneous taxa) drifting during above versus below bankfull water levels. However, terrestrial taxa were significantly (P < 0.05) over‐represented (23–25% of the total) at flood peak and a small secondary flood peak four days later. In addition, aquatic taxa which normally are scarce in drift samples at the Seebach (e.g. oligochaetes, ostracods) were abundant during the receding main flood event.Above bankfull stage (water level ⩾ 70 cm), animal drift densities were significantly (P < 0.01) and up to 22‐times higher (e.g. 45.6 individuals m−3) than during baseflow (e.g. 2.1 individuals m−3). Below bankfull stage, drift densities remain constant, independent of water discharge (Student‐Newman‐Keuls test; P < 0.01). In LPOM drift, this ratio was nearly 100: 1, with drift values ranging from 1.83 g dry weight m−3 at flood peak to 0.02 g dry weight m−3 at baseflow. Drift densities of animals and LPOM exhibited a positive exponential relationship with water level.Drift rates of anmimals and LPOM ranged from 3200700 individuals and 148.9 kg dry weight per hour at flood peak to 17440 individuals and 0.2 kg dry weight per hour at baseflow. During a single receding flood (water level ⩾ bankfull) significantly more organisms and LPOM were transported than during a whole year at baseflow discharge.
Changes in the lower trophic levels as a consequence of the level of fish manipulation in the ponds
Authors: Tátrai István , Oláh János , Paulovits Gábor , Mátyás Kálmán , Kawiecka Barbara J. , Pekár Ferenc 
Published: February 2007

AbstractCyprinid fish of different mature age classes (3+ ‐4+) and stocks (100, 300 and 500 kg/ha) were introduced into each of three experimental ponds with area of 0.3 ha (average depth ca 1.7 m) while the fourth pond was left free of fish. Bream (Abramis brama L.), white bream (Blicca bjoerkna L.) and roach (Rutilus rutilus L.) made up 75% of the total cyprinid biomass, with wild carp (Cyprinus carpio L.) as the remaining 25%. The introduced fish spawned successfully.The high (above 300 kg/ha) planktivorous and benthivorous fish stocks resulted in several qualitative and quantitative alterations of the food chain structure in our simulation pond experiments. These alterations must primarily be assigned to changes caused by both the zooplanktivory and benthivory nature of the stocked fish populations. At the higher levels of fish biomass, Secchi depth was influenced significantly by chlorophyll‐a concentration. Most of the variance in suspended solids concentration could be explained by the biomass ratio of the mature benthivorous fish. There was a clear shift in algal cell size in the ponds with the higher fish stocks: ponds with more fish had larger cells later in the summer. The relative influence of young cyprinid fish on crustaceans species composition and biomass, and mature populations on benthic fauna abundance and biomass, was sufficiently greater at higher (300–500 kg/ha) fish stock rates.
The hyporheic zone: Hydrogeological and geochemical study of a stream in the pyrenees mountains
Authors: Rouch Raymond , Mangin Alain , Bakalowicz Michel , D'Hulst Dominique 
Published: February 2007

AbstractThe hydrogeological and geochemical characteristics of the hyporheic zone were studied for a year on a 30 m2 site within a stream in the Pyrenees Mountains. This included the drawing of potentiometric maps, measuring hydraulic conductivity and porosity, and the monthly analysis of major chemical elements in water samples.Use of the combined data led to the clarification of certain aspects of the characteristics, functioning and development of the hyporheic zone.Even though the area studied lies in a zone of groundwater recharge, the direct vertical exchange between surface‐ and groundwater does not seem to be determinant in the potentiometric and chemical development of the area. However, the state of reserves, which can be reduced or reconstituted, seems to play an essential role in flow dynamics, and thus of the chemistry of this area. Flow dynamics in the hyporheic zone apparently are of the longitudinal‐transversal type, related to the local stream morphology.The results show how difficult it is to define the hyporheic zone in a structural sense, even though the zone represents an entity that is clearly characterized by specific and identifiable dynamics.
Factors that Control the Species Composition of Freshwater Phytoplankton, with Special Attention to Nutrient Concentrations
Authors: Aakanishi Masami , Monsi Masami 
Published: February 2007

AbstractVariations of species composition and population size of planktonic algae were studied in relation to the different nutrient levels in a eutrophic pond and an oligotrophic lake. The results obtained were discussed in comparison with the changes in photosynthesis and chlorophyll of several algal populations cultured under different nutrient conditions. As based on unialgal culture experiments two types of algae (the Chlorella‐type and the Melosira‐type) could be distinguished with regard to variations of photosynthesis and chlorophyll in response to different nutrient levels. Distribution of the Chlorella‐type algae may be confined to eutrophic waters, while the Melosira‐type algae can be distributed widely in waters from oligotrophic to eutrophic.
An Evaluation of the Effects of Environmental Variables on Marine Plankton Primary Productivity by Multivariate Regression
Authors: Hameedi M. Jawed 
Published: February 2007

AbstractStepwise multiple regression analysis has been used to evaluate the relative importance of environmental variables for primary productivity in oceanic areas off Washington and Oregon, USA. Special emphasis has been placed on the area affected by the Columbia River plume. In the plume, a large proportion of the total variability in primary productivity data is explained by only four variables: chlorophyll a, nitrate, depth of the photic zone, and temperature. In ambient sea water, the significant variables are salinity, temperature, solar radiation of the previous day, vertical stability in the upper 100 m, and phosphate. Analysis of the combined data indicates that, in the spring, primary productivity depends on chlorophyll a concentration alone. The results are explained from the biological and physical points of view. The usefulness of multiple regression analysis for marine ecosystem studies appears to be limited.
Some Observations on the Influence of Salinity on Photosynthetic Activity and Chloride Ion Loss in Several Seaweeds
Authors: Ohno Masao 
Published: February 2007

AbstractThe photosynthetic rates of Enteromorpha intestinalis, Fucus vesiculosus and Laminaria saccharina from the Baltic Sea were measured in different salinity range of Medium A (with NaHCO3) and Medium B (without NaHCO3). Photosynthetic activity in Medium A showed higher values than those in Medium B. The materials pretreated for one day showed a higher O2 output than those untreated at almost every salinity range. In a chloride loss experiment the pretreated thalli of Porphyra umbilicalis, Fucus vesiculosus and Laminaria digitata were placed for a three minute period in distilled water. The excreted chloride ion content showed a higher value in sublittoral species after hypotonic and hypertonic treatment than in intertidal species.
Cercaria orospinosa Encountered in the Snail Melanopsis praemorsa L. from a Mountain Stream in Turkey
Authors: Tareen Inam U. 
Published: February 2007

AbstractCercaria orospinosa is the only cercaria shed by Melanopsis praemorsa snails in Savanda stream, Turkey. Magnitude of infestation of snails by this cercaria was correlated with size of the snails and strength of the water current. The highest degree of infestation occurred in June, while in winter it was reduced to zero. The cercariae were released from rediae, which were found in the hepatopancreas of the snails.
Estimating Competition in Cladocerans Using Data on Dynamics of Clutch Size and Population Density
Authors: Gnauck A. , Matveev Vladimir 
Published: February 2007

AbstractNegative correlations between clutch size and population density are proposed to be considered as indices of intra‐ and interspecific competition in cladocerans if they are revealed while analyzing population dynamics and clutch size and time lags are taken into account. The proper correlation analysis of summer populations of Diaphanosoma brachyurum, Bosmina coregoni, Daphnia cucullata and D. galeata from mesotrophic Lake Glubokoye (Moscow Region) in 1975, 1978, and 1979 indicates the important role of competition of both types for the community studied. High niche overlap in food and space in the four populations was also observed.