INVESTIGADORES
ISLA Federico Ignacio
artículos
Título:
Dead diatom assemblages in surface sediments from a low
Autor/es:
HASSAN, G; ESPINOSA, M.; ISLA F
Revista:
Hydrobiologia
Editorial:
Springer Verlag
Referencias:
Año: 2007 vol. 579 p. 257 - 270
Resumen:
In the context of a main project that
aims to recover modern data on diatom distribu-
tion applicable to paleosalinity reconstructions in
coastal areas of Southern South America, the
composition and distribution of dead diatom
assemblages in the littoral zone of the Queque´n
Salado estuary (Argentina) were studied. Diatom
zones were defined along the estuarine gradient
by cluster analysis and related to the salinity
range and sediment composition by Canonical
Correspondence Analysis. Four diatom zones
were identified. A mixture of marine, brackish
and freshwater diatoms, probably allochthonous,
characterized the inlet (zone I). Marine/brackish
taxa, represented mainly by Paralia sulcata dom-
inated zone II, characterized by polyhaline con-
ditions and sandy sediments. Zone III was
characterized by mesohaline conditions, muddy
sediments and the dominance of the estuarine
diatom Amphora helenensis. Brackish/freshwater
and freshwater diatoms dominated the headwa-
ters (zone IV), where salinity was always below
5&. The comparison of Queque´n Salado diatom
assemblages with previous results from the Que-
que´n Grande estuary showed a similar taxonomic
composition between both estuaries. However,
differences in the salinity ranges of the estuaries
(related to differences in the degree of human
impact and tidal range) lead to a displacement in
their spatial distribution along the longitudinal
estuarine axis. This paper contributes to the
knowledge of the ecological requirements of
South American estuarine diatoms and provides
useful data for paleosalinity reconstructions in the
region.