نتایج جستجو برای: plankton achievement
تعداد نتایج: 52290 فیلتر نتایج به سال:
This paper analyses long-term and seasonal changes in the North Sea plankton community during the period 1970 to 2008. Based on Continuous Plankton Recorder (CPR) data covering 38 yr, major changes in both phytoplankton and zooplankton abundance and community structure were identified. Regime changes were detected around 1978, 1989 and 1998. The first 2 changes have been discussed in the litera...
The Sheldon spectrum describes a remarkable regularity in aquatic ecosystems: the biomass density as a function of logarithmic body mass is approximately constant over many orders of magnitude. While size-spectrum models have explained this phenomenon for assemblages of multicellular organisms, this paper introduces a species-resolved size-spectrum model to explain the phenomenon in unicellular...
Water is one of the most natural resources for all the living organisms, weather unicellular or multi cellular, since it is required for various domestic purposes irrigation, power generation and industries. In a freshwater system, the zooplankton forms are important group and constitute basic link of the food chain. Planktons are very sensitive to the environment they live in and any alteratio...
Plankton diversity, physical and chemical variables and chlorophyll a were analyzed in two shallow urban reservoirs with different trophic degrees on Pernambuco State, northeastern Brazil. High eutrophication levels were observed in Apipucos reservoir, while Prata reservoir was considered oligotrophic. Values reported for physical and chemical variables and chlorophyll a differed among the stud...
Plankton communities and macrofauna associated to aquatic macrophyte stands in a shallow water-supply reservoir (21°14'09″S; 48°18'38″W) on an aquaculture farm were compared to evaluate the relationship between organism densities and some abiotic features of the reservoir. Water and communities associated were sampled at two sites, one in an area with the predominance of Eichhornia azurea (Sw.)...
Polychlorinated biphenyl (PCB) and polybrominated diphenyl ether (PBDE) concentrations and profiles in paired sediment-plankton samples were determined along a 500 km transect in coastal British Columbia, Canada. PCB and PBDE levels in sediment were both greater in the industrialized Strait of Georgia than in remote northern sites and exhibited parallel spatial trends. In plankton, recent-use P...
The class Thaliacea belongs to Urochordata which branched from phylum chordata. Thaliacea have three orders: Doliolida (Cyclomyaria), Pyrosomatida and Salpida (Desmomyaria) and all are considered marine plankton, holoplankton and microphages. These animals feed by filtering water through their body. The aim of this research was to identify and study the ecological processes of the tunicates in ...
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