Metazooplankton community in coastal sub-Antarctic waters (Beagle Channel), with emphasis on the smaller size fractions: spatial and temporal variability. Marine Biological Research.

AGUIRRE, GASTON; CAPITANIO, FABIANA; LOVRICH, GUSTAVO A.; ESNAL, GRACIELA

MARINE BIOLOGY RESEARCH

TAYLOR & FRANCIS AS

Año: 2011 vol. 8 p. 341 - 353

1745-1000

The aim of this study was to analyse the variability in the species composition and abundance of the metazooplanktoncommunity in different coastal areas of the Beagle Channel (southern tip of South America) during a seasonal cycle.Sampling was conducted during November (spring) 2005, March (summer), June (autumn) and September (winter) 2006at 12 coastal stations. Copepods were the most abundant group throughout the study, and their assemblages were composedof a mixture of species typical of the south-western Atlantic, the south-eastern Pacific and the Southern Ocean. Amongthem, Oithona similis, Ctenocalanus citer and Drepanopus forcipatus were the dominant species. The copepod Acartia tonsa wasthe only taxon that displayed a spatial pattern of abundance, showing higher densities in areas with lower salinities. Thecommunity structure showed a strong temporal pattern. The metazooplankton community in March and June was mainlycomposed of copepods, while in November and September the community showed a greater diversity. In these two monthshigh densities of meroplanktonic larvae were found, in coincidence with higher chlorophyll-a concentration. This temporalpattern seems to be more dependent on primary production than on physical factors such as temperature or salinity. Theabsence of a clear spatial pattern may suggest that the studied area of the Beagle Channel behaves as a semi-enclosed waterbody.