INVESTIGADORES
SCHIARITI Agustin
congresos y reuniones científicas
Título:
Gelatinous zooplankton off the Argentinean continental shelf: winter distribution, estimated biomass and significance for pelagic community
Autor/es:
SCHIARITI, A.; GIBERTO, D. A.; MIANZAN H. W
Lugar:
Hiroshima, Japón
Reunión:
Simposio; 4th International Zooplankton Production Symposium; 2007
Institución organizadora:
PICES, Univertity of Hiroshima, GLOBEC, ICES
Resumen:
Beyond
their seasonal fluctuations in abundance, jellies seem to be increasing their numbers
on the ocean ecosystems. There are, nevertheless, few historical data to
support that perception. Furthermore, their
contribution to the production of pelagic environments remains uncertain. Distribution,
abundance and biomass of jellyfish were studied using 152 samples (MWT net) off
the Argentinean Continental Shelf (39-50ºS; 61-34ºW) in winter of 1988.
Multivariate analyses were applied to investigate gelatinous zooplankton
community structure and their relationship with water masses. We found 11
species of gelatinous zooplankton. Their distribution patterns were related to
the distribution of water masses. The most abundant species were Pegea confederata and Calycopsis sp. (0.002 ind./m3).
Jellyfish biomass was dominated by Periphylla
periphylla reaching 39% (13.9 mg/m3) of the wet weight (ww),
38.7% (0.5 mg/m3) of the dried weight (dw) and 33.6% (0.01 mg/m3)
of the organic Carbon content (org. C). Biomass of the pelagic community was
dominated by jellyfish reaching the 66.3% of the ww (35.5 mg/m3). In
terms of dw and org. C, however, the pelagic environment was dominated by
non-gelatinous species which represented 75.8% of the dw (3.8 mg/m3)
and 97.9% of the org. C (1.8 mg/m3). These results suggest that
gelatinous zooplankton could play an important role in the pelagic ecosystem as
carnivorous or filtering species. However, in winter of 1988, they would had not
contribute significantly to the pelagic standing stock. The historical data
presented in this work would constitute a baseline for testing possible
increases in jellyfish abundance.