IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Thalassiosira minima as ecological indicator of long term changes in summer blooms dynamics in Bahía Blanca estuary (Argentina)
Autor/es:
GUINDER V. A.; POPOVICH C. A.; MOLINERO J. C.; PERILLO G. M. E.
Lugar:
IFM-GEOMAR, Kiel, Alemania
Reunión:
Conferencia; AQUASHIFT. Life in warming waters; 2010
Institución organizadora:
IFM-GEOMAR
Resumen:
Coastal and estuarine ecosystems are highly sensitive to human and climate change stressors. The growing need for the assessment of long term changes at the base of pelagic food webs and the forecast of ecological responses under warming scenarios are current challenges in ecological studies. In the Bahía Blanca Estuary, Argentina, the winter-early spring diatom bloom has been ascribed as the main feature of the phytoplankton dynamics for the period 1978-2002. In recent years 2005-2008, however, noticeable changes have been observed including an increase in the phytoplankton biomass in summer. In recent years, summer blooms have been dominated by the diatom Thalassiosira minima which, in 2008, reached up to 4.3 x 106 cells l-1 which represents the 85 % of the total phytoplankton abundance. Although this species has been previously reported in the estuary since 1994 it was always observed in low densities, while flagellates were the dominant phytoplankton group in summer. The high biomass reached by T. minima in the recent years was related with high water turbidity, light extinction coefficients k, and water temperature. Our results suggest that the long term changes of T. minima integrate the modifications the Bahía Blanca Estuary has undergone in the last decade. The close link between T. minima and the environmental parameters that now characterize the Bahía Blanca Estuary allows suggesting that this species may be used as indicator of the estuarine ecosystem state.