GEOCHEMICAL AND FAUNAL VARIABILITY OF OSTRACODE FAUNAS FROM SALINE PONDS ON SAN SALVADOR ISLAND, BAHAMAS—AN INTEGRATED TAXONOMIC AND GEOCHEMICAL ATLAS

Ostracode faunas from eleven lakes ranging from normal marine to hypersaline conditions on San Salvador Island, Bahamas were examined to determine: 1) if lakes of higher salinity have different diversities than less saline lakes and 2) if there is a correlation between species distribution and water chemistry. Water and ostracode samples were collected and analyzed using ICPMS as well as field geochemical testing. Lake salinity was found to correlate with alpha diversity with peak diversity occurring at the calcite branchpoint. As salinity increases, alpha diversity decreases. There is little correlation between species distribution and lake chemistry or geographic proximity. An exception to this are hypersaline lakes that have low alpha diversity and contain only euryhaline, cosmopolitan species. Surprisingly, dissimilar faunas occurred in adjacent lakes with similar chemistry. Lakes that were similar in chemistry were sometimes geographically separated by distance or by a significant barrier. This similarity indicates that dispersal of ostracodes may not necessarily be as frequent and widespread as conventional wisdom has surmised. In addition, these data have been compiled and placed into the first taxonomic and geochemical atlas of Caribbean ostracodes. This database was developed using standard PC-based database software and consists of over 60 senior synonym species records that include morphologic descriptions, ESEM images, distribution maps and geochemical tolerances. This database will be made available online on the Gerace Research Center's website (http://www.geraceresearchcenter.com) and will be expanded to include the greater Caribbean basin as well as core and stratigraphic distributions, providing a major step toward stabilizing taxonomic concepts of non-marine Caribbean ostracode species.