MARINE ENVIRONMENTS

Faunal Associations and Salinity (cont'd)

The following is a figure (Rodrigues) that shows the distribution of late glacial and postglacial macrofaunal associations and microfaunal assemblages with respect to salinity in the western basin of the Champlain Sea.  The numbers used in this figure correspond to those used for the associations and assemblages listed on the previous page.

The figure indicates that the foraminiferal assemblages are quite specific to their corresponding salinity zone, however the diversity of the individual species within the assemblages (the same species can be part of several assemblages) overlap in high, intermediate and low salinity bottom water zones.  This information is based on the Shannon-Wiener Information Function, [H(S)], which is a diversity measure of the number of species within a sample of a particular system.  For foraminifera species, the diversity in high salinity water ranges from 0.05 1.98; in intermediate salinity water, 0.00 1.89; and in low salinity water, 0.38 1.89.  This indicates that the diversity of the foraminiferal species themselves in not directly related to the paleosalinity of the Champlain Sea.  The same conclusions were reached for ostracode species.  While the general distribution of the ostracode assemblages corresponds to the bottom water salinity levels, there is quite an overlap in the diversity of the individual species with respect to these levels.

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