905 resultados para nutrients and biomass


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On the basis of analyses of samples collected in the eastern Black Sea in September 1996 trends of increase in surface zooplankton biomass and general decrease in Mnemiopsis biomass were revealed.

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The Longitudinale 1987-1991dataset contains zooplankton data collected from May to October 1987-1991 in 14 station allong 2 transect paralel to the romanian littoral. Zooplankton sampling was undertaken at 14 stations where samples were collected using a Juday closing net in the 0-10, 10-20, 20-30 and 30-40 layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

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The Est Constanta 1978 dataset contains zooplankton data collected monthly from January 1978 to december 1978 allong a 5 station transect in front of the city Constanta (44°10'N, 28°41.5'E - EC1; 44°10'N, 28°47'E - EC2; 44°10'N, 28°54'E - EC3; 44°10'N, 29°08'E - EC4; 44°10'N, 29°22'E - EC5). Zooplankton sampling was undertaken at 5 stations where samples were collected using a Juday closing net in the 0-10, 10-25, 25-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

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The Gurile Dunarii 1977 dataset contains zooplankton data collected in April and September 1977 in 14 station allong 3 transect in front of the Danube Delta. Zooplankton sampling was undertaken at 14 stations where samples were collected using a Juday closing net in the 0-10, 10-20, 20-30, 30-40 and 40-50m layer (depending also on the water masses). The dataset includes samples analysed for mesozooplankton species composition and abundance. Sampling volume was estimated by multiplying the mouth area with the wire length. Taxon-specific mesozooplankton abundance was count under microscope. Total abundance is the sum of the counted individuals. Total biomass Fodder, Rotifera , Ctenophora and Noctiluca was estimated using a tabel with wet weight for each species an stage.

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Studies were carried out in the northeastern Sea of Okhotsk, in the zone of interaction of the West Kamchatka and Compensating Currents at the beginning of spring seasonal succession from March 23 to April 14,1998. Samples for analysis of pigmentary and species compositions of phytoplankton were taken from the sea surface layer, depth 0.5 m. To reduce influence of micropatchiness on phytoplankon distribution at each station subsamples 0.7-1 l were collected every 50-100 m. These subsamples were used to make integral samples 4.5-8.0 l. Phytoplankton biomass and concentration of chlorophyll a varied from 18.7 to 490.9 mg/m**3 and from 0.129 to 2.422 mg/m**3, respectively. Total concentration of phytoplankton pigments varied from 0.622 to 6.679 mg/m**3. In samples studied 51 species of microalgae from 5 orders were found. In terms of the number of species, Bacillariophyta (31 species) and Dinophyta (15 species) prevailed. Diatomaceous algae make up more than 80% of the total phytoplankton biomass in waters of the Compensating Current, from 50 to 80% in intermediate waters, and less than 50% in waters of the West Kamchatka Current. Phytoplankton populations consisting primarily of diatoms were characterized by very low chlorophyll a to biomass ratio (0.1 %). It is three times lower than the ratio observed in phytoplankton populations that were close by species composition and size composition in this area in the late April-early May 1996.