IADO   05364
INSTITUTO ARGENTINO DE OCEANOGRAFIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
VERTICAL DISTRIBUTION OF EURYTEMORA AMERICANA
Autor/es:
MENÉNDEZ, M. C.; HOFFMEYER, M. S.; PICCOLO, M.C.; FERNÁNDEZ SEVERINI, M.D.
Lugar:
Buenos Aires
Reunión:
Jornada; VIII Jornadas Multidisciplinarias de la SAB; 2006
Institución organizadora:
Sociedad Argentina de Biología
Resumen:
Vertical distribution of zooplankton is a complex phenomenon involving differents
behaviors that change according to species and individual. This distribution depend on
factors suchs as age, sex and spawning and external factors such as tidal cycles, lunar
phase, light intensity, temperature and salinity. This study analyze the influence of
tide and physical and chemical variables on vertical distribution of developmental
stages of E. americana. Sampling was conducted at Cuatreros Port in August 2005.
Samples were taken every three hours at surface and bottom over a 14-hour period.
Submersibles pumps discharging into 200 µm mesh nets were used. Salinity,
temperature, chlorophyll a, particulate organic matter and suspended sediment were
measured at each time. Temperature range was 9.8-11.6 ºC and salinity 29.3-33.2.
Chlorophyll a was higher at surface whereas the highest concentration of suspended
sediment was registered during flood at bottom. Densities at surface ranged between
3.1-1725.7 ind m-3 and between 4.7-971.9 ind m-3 at bottom. Copepodids I-III
dominated at surface during all tidal cycle and the highest value was observed during
ebb. A similar pattern ocurred at bottom, although during flood copepodids IV-V
were more abundant and the differences in abundance were not as marked as in
surface. Adults males and females showed a similar pattern along the tidal cycle
(surface and bottom) but males were always more abundant than females. Nauplius,
copepodids I-III and IV-V were, in general, more abundant at surface while males and
females at bottom. Differences in the abundances would indicate that the stages are
distributed differentially in the water column and that the tide influences their position
in the water column.