IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Long term changes on Tintinnids community in an estuarine system from the SW Atlantic Ocean
Autor/es:
MARCOVECCHIO J.E.; MOLINERO J.C.; HOFFMEYER M.S.; BARRÍA DE CAO M.S.; PERILLO G.M.E.; LÓPEZ ABBATE M.C.
Lugar:
Honolulu
Reunión:
Congreso; ASLO 2017 - Mountain to the Sea; 2017
Institución organizadora:
ASLO
Resumen:
Microzooplankton are primary consumers of phytoplankton and can quickly transfer environmental signals into the pelagic food web. However, the scarcity of long term data prevent the assessment of their long term sensitivity to mounting anthropogenic and climate stress. Here we analysed the response of tintinnids to multiple environmental drivers in the Bahía Blanca estuary (SW Atlantic Ocean) over the last decades (1986-2011). Tintinnids are the dominant micrograzers in the estuary. However, their abundance displayed a decreasing trend with an annual rate of decline of 5% (p=0.00) since 1986. All recorded species, including the dominant Tintinnidium balechi, and chlorophyll concentration followed the same negative trend. The best GAM model, based on the minimization of the Akaike?s information criterion, revealed that the concentration of tintinnids significantly responded to turbidity (p=0.02), seawater temperature (p=0.05), wind speed (p=0.00) and chlorophyll (p=0.68). In addition, SEM revealed an increasing interplay among environmental drivers derived from mounting anthropogenic stress and climate forcing. We hypothesize that the long term negative trend of tintinnids resulted from the hampering effect (e.g. mechanical damage of cells, increased investment in food supply) of high resuspension and sedimentation derived from dredging operations. In addition, the magnitude of environmental shift and the increasing number of direct and indirect drivers likely exceeded the tolerance level of species thereby contributing to their decline. Our results warn on the potential cascading effect such multiple environmental drivers may have on ecosystem assets.