INVESTIGADORES
MENENDEZ Maria Clara
congresos y reuniones científicas
Título:
Long-term trend in the mesozooplankton abundance in a southwestern temperate estuary (Bahía Blanca Estuary, Argentina)
Autor/es:
MELISA D. FERNÁNDEZ SEVERINI; ANABELA A. BERASATEGUI; VALERIA A. GUINDER; MARÍA C. MENÉNDEZ; FLORENCIA BIANCALANA; M. SOFIA DUTTO; M. CELESTE LÓPEZ ABBATE; MÓNICA S. HOFFMEYER
Lugar:
Pucón
Reunión:
Simposio; 5th International Zooplankton 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 pattern 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.