CERZOS   05458
CENTRO DE RECURSOS NATURALES RENOVABLES DE LA ZONA SEMIARIDA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Long-term variability in summer phytoplankton blooms as fingerprints of climate change in a temperate estuary in the southern hemisphere
Autor/es:
GUINDER V. A.,; POPOVICH C. A.; MOLINERO J. C., PERILLO G. M. E; PERILLO G. M. E
Lugar:
Boulogne sur Mer, Francia.
Reunión:
Simposio; Climate Change Impacts on Estuarine and Coastal Ecosystems: a Zooplankton Perspective; 2010
Resumen:
  Spring phytoplankton blooms are ubiquitous in temperate coastal systems, while summer blooms have gained attention in the last decade as a consequence of recurrent strong phytoplankton blooms. Although these changes have been linked to both climate-related environmental changes and increasing anthropogenic disturbances, the causes remain matter of debate. Here we have examined austral summer phytoplankton data (December – March) that covered the years 1978-2008 and compared with hydrological and meteorological variations in the Bahía Blanca Estuary, Argentina. Chlorophyll concentration remained constant over the studied period while the phytoplankton abundance (in cells l-1) increased markedly. Concomitant to these changes we found a shift in the phytoplankton community from a dominance of phytoflagellates and relatively large diatom species towards a dominance of a small (5-15 µm) diatom species: Thalassiosira minima which reached up to 86 % of the total abundance in summer 2008. Long-term atmospheric conditions revealed an increase in temperature and a marked decrease in precipitation, which has affected the hydrographic elements in the estuary (i.e. warmer and saltier waters). Such modifications in water mass properties have likely affected niches phytoplankton species in recent summers and likely promoted T. minima outburst and its dominance over other species. These results allow hypothesizing that the climate warming is triggering the occurrence of summer phytoplankton blooms and modifications in community structure in the Bahía Blanca Estuary. Further studies should focus on the autoecology of T. minima to evaluate species’ life history responses to both climate and anthropogenic disturbances.