INVESTIGADORES
FERNANDEZ SEVERINI Melisa Daiana
congresos y reuniones científicas
Título:
Long-term trend in the mesozooplankton abundance in a Southwestern temperate estuary (Bahía Blanca Estuary, Argentina)
Autor/es:
FERNÁNDEZ SEVERINI MELISA DAIANA; BERASATEGUI ANABELA ANAHÍ; GUINDER VALERIA ANA; MENÉNDEZ MARÍA CLARA; BIANCALANA FLORENCIA; DUTTO MARÍA SOFÍA; LÓPEZ ABBATE M. CELESTE; HOFFMEYER MÓNICA SUSANA
Lugar:
Pucón
Reunión:
Simposio; 5th International Zoocplankton Production Symposium; 2011
Resumen:
Estuarine ecosystems are sensitive to anthropogenic and hydroclimatic modifications and emerge as important areas to study the functioning of pelagic food webs. Here, we analyzed mesozooplankton and phytoplankton data from the Bahía Blanca Estuary that cover the years 1980-2007 in relation to environmental conditions. The mesozooplankton is mainly dominated by two key copepods: Acartia tonsa and Eurytemora americana, which have shown a recurrent annual patter during the considered period. Acartia tonsa has largely dominated during most of the year with maximal abundances in summer-early autumn while E. americana has been dominant in late winter-spring coinciding with the phytoplankton annual bloom. Eurytemora americana feeds mostly on diatoms and disappears from the plankton habitat after the collapse of the phytoplankton bloom and remains as resting eggs in bottom sediments. In the last decade, noticeable variations on this pattern have been observed. The abundance of both copepods, especially in 2005 and 2007, increased significantly and it was mainly related to water temperature and salinity. On the other hand, the phenology of the phytoplankton bloom has changed (e.g. magnitude, timing and species composition) what has probably affected the trophic interactions and the pelagic food web structure. The shifts on zooplankton abundance could be linked to changes in hydrological conditions in the estuary (i.e. temperature and salinity) and phytoplankton due to its strong dependence on these variables. However, the present work is the starting point and future studies are necessary to attempt this issue.