Pelagic communities and ecosystem processes in Andean Patagonian lakes

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Limiting nutrients, nitrogen and phosphorus, are of crucial importance in the structure and dynamics of freshwater plankton. Oligotrophic lakes are nutrient limited environments and therefore their plankton dynamics depends mostly on internal mechanisms of recycling. The plankton dynamics and food w...

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Autores principales: Balseiro, Esteban, Modenutti, Beatriz E.
Lenguaje:Inglés
Publicado: 1998
Acceso en línea:https://hdl.handle.net/20.500.12110/ecologiaaustral_v008_n02_p183
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:ecologiaaustral_v008_n02_p1832023-10-03T13:33:12Z Pelagic communities and ecosystem processes in Andean Patagonian lakes Balseiro, Esteban Modenutti, Beatriz E. Limiting nutrients, nitrogen and phosphorus, are of crucial importance in the structure and dynamics of freshwater plankton. Oligotrophic lakes are nutrient limited environments and therefore their plankton dynamics depends mostly on internal mechanisms of recycling. The plankton dynamics and food web structure of Andean lakes were analysed linking the biogeochemical cycles and classic food web ecology. As in other oligotrophic waters, the producer trophic level of Andean lakes is formed by a phytoplankton dominated by small cells. A particular feature of these lakes is that the herbivorous zooplankton is restricted to rotifers and small crustaceans with body length < 1 mm. The direct effect of grazing decreases nanoplanktonic cells abundance but, the indirect effect of zooplankton (through nutrient recycling) results in an increase in netphytoplankton, particularly diatoms. Changes ín the zooplankton constitution over the annual cycle may change the nutrient supply ratio. The copepod Boeckella gracilipes decreased P limitation lowering the N:P ratio whereas the dominance of the cladoceran Bosmina longirostris increased the N:P ratio and therefore increased P limitation during summer. In addition, predation by larvae of the authoctonous fish Galaxias maculatus change the quality and quantity of grazers since their predation on Boeckella nauplii provokes the failure of the summer cohort of the copepod. Consequently, zooplankton composition and the elemental ratios of recycled nutrients change. These results suggest that top-down and bottom-up effects of pelagic food webs cannot be easily separated. 1998-12 PDF Inglés info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc-sa/2.5/ar https://hdl.handle.net/20.500.12110/ecologiaaustral_v008_n02_p183
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
language Inglés
orig_language_str_mv Inglés
description Limiting nutrients, nitrogen and phosphorus, are of crucial importance in the structure and dynamics of freshwater plankton. Oligotrophic lakes are nutrient limited environments and therefore their plankton dynamics depends mostly on internal mechanisms of recycling. The plankton dynamics and food web structure of Andean lakes were analysed linking the biogeochemical cycles and classic food web ecology. As in other oligotrophic waters, the producer trophic level of Andean lakes is formed by a phytoplankton dominated by small cells. A particular feature of these lakes is that the herbivorous zooplankton is restricted to rotifers and small crustaceans with body length < 1 mm. The direct effect of grazing decreases nanoplanktonic cells abundance but, the indirect effect of zooplankton (through nutrient recycling) results in an increase in netphytoplankton, particularly diatoms. Changes ín the zooplankton constitution over the annual cycle may change the nutrient supply ratio. The copepod Boeckella gracilipes decreased P limitation lowering the N:P ratio whereas the dominance of the cladoceran Bosmina longirostris increased the N:P ratio and therefore increased P limitation during summer. In addition, predation by larvae of the authoctonous fish Galaxias maculatus change the quality and quantity of grazers since their predation on Boeckella nauplii provokes the failure of the summer cohort of the copepod. Consequently, zooplankton composition and the elemental ratios of recycled nutrients change. These results suggest that top-down and bottom-up effects of pelagic food webs cannot be easily separated.
author Balseiro, Esteban
Modenutti, Beatriz E.
spellingShingle Balseiro, Esteban
Modenutti, Beatriz E.
Pelagic communities and ecosystem processes in Andean Patagonian lakes
author_facet Balseiro, Esteban
Modenutti, Beatriz E.
author_sort Balseiro, Esteban
title Pelagic communities and ecosystem processes in Andean Patagonian lakes
title_short Pelagic communities and ecosystem processes in Andean Patagonian lakes
title_full Pelagic communities and ecosystem processes in Andean Patagonian lakes
title_fullStr Pelagic communities and ecosystem processes in Andean Patagonian lakes
title_full_unstemmed Pelagic communities and ecosystem processes in Andean Patagonian lakes
title_sort pelagic communities and ecosystem processes in andean patagonian lakes
publishDate 1998
url https://hdl.handle.net/20.500.12110/ecologiaaustral_v008_n02_p183
work_keys_str_mv AT balseiroesteban pelagiccommunitiesandecosystemprocessesinandeanpatagonianlakes
AT modenuttibeatrize pelagiccommunitiesandecosystemprocessesinandeanpatagonianlakes
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