This article explores the potential role of UV radiation (UVR) as an influence on zooplankton com... more This article explores the potential role of UV radiation (UVR) as an influence on zooplankton communities. In the first section we provide a general overview of UVR effects on freshwater zooplankton, with an emphasis on Argentine and Chilean environments. In the second section we present the results of a survey involving 53 temperate lakes across a gradient of UVR exposure to determine patterns of species richness and specific diversity. These community characteristics decreased at high potential UVR exposure (i.e. high mean water column irradiance or low lake optical density). A threshold value of mean water column irradiance of approximately 10% of the surface level seems to limit both richness and diversity to minimum values. On the basis of the collected evidence it is not possible to definitely conclude that UVR rather than another covarying factor is responsible for the decrease in specific diversity observed at the lowest end of lake optical depth. However, lakes with values ...
... Viviana A. Alder*, Ana Baldoni*, María S. Barría*, Ricardo O. Bastida*, Alicia S ... Mariela ... more ... Viviana A. Alder*, Ana Baldoni*, María S. Barría*, Ricardo O. Bastida*, Alicia S ... Mariela Kogan*, Gustavo A. Lovrich*, Adrián O. Madirolas*, Juan P. Martin*, Patricia Martos*, María L ... y Técnicas 2Instituto Nacional de Investigación y Desarrollo Pesquero, Paseo Victoria Ocampo Nº ...
This is the first characterization of the structure and temporal variation of the plankton commun... more This is the first characterization of the structure and temporal variation of the plankton communities comprising the complete food web in five peat bog pools related to environmental factors over two consecutive ice-free periods in Tierra del Fuego (548S). Remarkably, picophytoplankton was composed solely of eukaryotic cells, surpassing the dominance expectations for these acidic water bodies, whereas testaceans were virtually absent, even as tychoplankters. Abundances of the different planktonic communities were slightly higher than those reported for Northern Hemisphere peat bogs and humic lakes. Mixotrophic nutrition prevailed among nano-and microphytoplankters, a strategy also common in humic lakes. The structures in spring of the planktonic communities were similar. In contrast, in late summer there were differences in the abundance and biomass of the different trophic compartments among small, shallow water bodies and large ones. These seem to be dictated by distinct pool size-driven patterns of water temperature variation. A general shift in the control of heterotrophic flagellates abundance in the pools occurred, changing from bottom-up regulation in spring to top-down control in late summer related to available online at www.plankt.oxfordjournals.org
This article explores the potential role of UV radiation (UVR) as an influence on zooplankton com... more This article explores the potential role of UV radiation (UVR) as an influence on zooplankton communities. In the first section we provide a general overview of UVR effects on freshwater zooplankton, with an emphasis on Argentine and Chilean environments. In the second section we present the results of a survey involving 53 temperate lakes across a gradient of UVR exposure to determine patterns of species richness and specific diversity. These community characteristics decreased at high potential UVR exposure (i.e. high mean water column irradiance or low lake optical density). A threshold value of mean water column irradiance of approximately 10% of the surface level seems to limit both richness and diversity to minimum values. On the basis of the collected evidence it is not possible to definitely conclude that UVR rather than another covarying factor is responsible for the decrease in specific diversity observed at the lowest end of lake optical depth. However, lakes with values ...
... Viviana A. Alder*, Ana Baldoni*, María S. Barría*, Ricardo O. Bastida*, Alicia S ... Mariela ... more ... Viviana A. Alder*, Ana Baldoni*, María S. Barría*, Ricardo O. Bastida*, Alicia S ... Mariela Kogan*, Gustavo A. Lovrich*, Adrián O. Madirolas*, Juan P. Martin*, Patricia Martos*, María L ... y Técnicas 2Instituto Nacional de Investigación y Desarrollo Pesquero, Paseo Victoria Ocampo Nº ...
This is the first characterization of the structure and temporal variation of the plankton commun... more This is the first characterization of the structure and temporal variation of the plankton communities comprising the complete food web in five peat bog pools related to environmental factors over two consecutive ice-free periods in Tierra del Fuego (548S). Remarkably, picophytoplankton was composed solely of eukaryotic cells, surpassing the dominance expectations for these acidic water bodies, whereas testaceans were virtually absent, even as tychoplankters. Abundances of the different planktonic communities were slightly higher than those reported for Northern Hemisphere peat bogs and humic lakes. Mixotrophic nutrition prevailed among nano-and microphytoplankters, a strategy also common in humic lakes. The structures in spring of the planktonic communities were similar. In contrast, in late summer there were differences in the abundance and biomass of the different trophic compartments among small, shallow water bodies and large ones. These seem to be dictated by distinct pool size-driven patterns of water temperature variation. A general shift in the control of heterotrophic flagellates abundance in the pools occurred, changing from bottom-up regulation in spring to top-down control in late summer related to available online at www.plankt.oxfordjournals.org
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