EFFECTS OF CLIMATE VARIABILITY AND FLUVIAL DISCHARGE ON BENTHIC HABITATS IN PATOS LAGOON ESTUARY (SOUTH BRAZIL)

Abstract : An historical analysis of the abundance and composition of submerged aquatic vegetation in Patos Lagoon estuary were performed for the last 30 years, by integrating recent monitoring results with previous studies and data. The biological data were analyzed relative to climate, hydrological and sediment parameters. Although high seasonal, interannual and interdecadal variability, drastic reductions in seagrass abundance could be observed at the end of the XX century. These changes were strongly correlated to precipitation anomalies and extreme events, some of which were thought to be associated to ENSO episodes. The higher fluvial discharge increased average water level and turbidity, reduced salinity and enhanced water and sediment movement. Subsequent dry periods, with lower fluvial discharge, high summer temperatures and salinities were characterized by shifts to drif algae dominated state, with further implications for the benthic ecology. The responses of seagrasses to unfavorable conditions were relatively fast, but the complete recover was a slow process (~10 years), depending on the establishment of a set of favorable water and sediment conditions. The reported changes in seagrass abundance may imposed ecological consequences, as the reduction of stable habitats for invertebrates and fishes. Summed to the existing fishing effort and the effects of fluvial discharge, reductions in seagrass abundance and distribution may be involved in decreases of some fisheries in Patos Lagoon estuary. Since climate models for South Brazil predict future increases in precipitation, fluvial discharge and temperature, the present results have implications on predicting the impacts of climate changes over the equilibrium of the estuarine system.
Type de document :
Communication dans un congrès
ClimECO2 International Summer School - Oceans, Marine Ecosystems, and Society facing Climate Change, Aug 2010, Brest, France
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http://hal.univ-brest.fr/hal-00502331
Contributeur : Ivo Grigorov <>
Soumis le : mardi 13 juillet 2010 - 17:40:40
Dernière modification le : mardi 13 juillet 2010 - 17:40:40

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  • HAL Id : hal-00502331, version 1

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Margareth Copertino, Ulrich Seeliger, Carlos Bemvenuti, Leonir Colling, Osmar Möller. EFFECTS OF CLIMATE VARIABILITY AND FLUVIAL DISCHARGE ON BENTHIC HABITATS IN PATOS LAGOON ESTUARY (SOUTH BRAZIL). ClimECO2 International Summer School - Oceans, Marine Ecosystems, and Society facing Climate Change, Aug 2010, Brest, France. 〈hal-00502331〉

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