There is a vivid debate on the relative importance of local and regional factors in shaping microbial communities, and on whether microbial organisms show a biogeographic signature in their distribution. Taking a metacommunity approach, spatial factors can become important either through dispersal limitation (compare large spatial scales) or mass effects (in case of strongly connected systems)....

During the years 2004-2006 the parasitological autopsies of three species of fish: roach Rutilus rutilus (L.), bream Abramis brama (L.) and perch Perca fluviatilis L. from three lakes situated in warmińsko-mazurskie voivodeship were done. The aim of this study was comparable analysis of Metazoan parasite communities which occur in roach, bream and perch in three lakes of river Łyna watershed. T...

Volcanic crater lakes scattered throughout western Uganda are important local sources of water and fish. Two representative but contrasting crater lakes near the Kibale National Park were sampled in 2000; the hyper-eutrophic Lake Saka, which is highly affected by agricultural practices, and the mesotrophic Lake Nkuruba that is still surrounded by intact forest. The food web structures in these ...

Although picophytoplankton (PP) (0.2-2 µm) are ubiquitous in lakes and oceans, their importance in rivers has rarely been studied. We examined PP assemblages during the ice-free period in five rivers of a temperate region varying in trophic state (9-107 µg/L total phosphorus) and water discharge (1-87 m3/s). In these rivers, PP abundance reached concentrations as high as those observed in lakes...

Although the emission of N(2) via anaerobic ammonium oxidation (anammox) is a key process in the elimination of nitrogenous compounds from aquatic environments, little information is available regarding its significance and the relevant microorganisms (anammox bacteria) in eutrophic freshwater lakes. In the present study, the anammox bacteria in the sediment of a eutrophic lake in Japan, Lake K...

The taxonomic richness, composition, abundance, and biomass of pelagic microcrustaceans (Cladocera Copepoda) were determined in 17 lakes the “Lagunas de Montebello” National Park, a karst lake district Chiapas State, southeast Mexico. selected aquatic bodies exemplify diversity area, which displays an anthropic impact gradient from impacted/eutrophic on NW to non-impacted/oligotrophic SE. Sampl...

Effects of eutrophication on arsenic speciation were studied in eutrophic Lake Kiba and mesotrophic Lake Biwa, Japan. By combining hydride generation atomic absorption spectrometry with ultraviolet irradiation, inorganic, methyl and ultraviolet-labile fractions of arsenic were determined. In both Lakes, inorganic species (As(V+III)) dominated over other forms of arsenic all the year round. Most...

Toxin-producing cyanobacteria have frequently been hypothesized to limit the ability of herbivorous zooplankton (such as Daphnia) to control phytoplankton biomass by inhibiting feeding, and in extreme cases, causing zooplankton mortality. Using limnocorral experiments in hyper-eutrophic ponds located in Alabama and Michigan (U.S.A.), we tested the hypothesis that high levels of cyanobacteria an...

Cell-free filtrates of axenic or bacterized cultures of the dominant blue-green algae from a freshwater lake inhibited the growth of diatoms isolated from the same lake. Lake waters, collected during blue-green algal blooms, also inhibited diatom growth. In situ observations over a 5-year period indicate that diatom bloom populations vary inversely with the levels of the preceding blue-green al...