Use of ostracodes as paleonvironmental tools in the interpretation of ancient lacustrine records.

Lacustrine ostracodes have been studied during the last three decades because of their apparent utility in reconstructing aquatic paleoenvironments. These microcrustaceans are ideal for paleoenvironmental analysis becau­ se: 1) they are cosmopolitan and abundant lacustrine inhabitants; 2) they show high diversity; 3) they are sensitive to climate-related limnological variations; 4) their valves incorporate sorne trace elements from host waters that may provide information on paleolimnologic conditions; and 5) valve calcification appears to be in stable carbon and oxygen isotope equilibrium with the host water. The purpose here is to compare the recent advances in these various approaches, as well as their limitations in paleolimnologic reconstructions. It is evident that our current knowledge is far from complete, but it is also true that the progress achieved has established a basis for quantitative paleoenvironmental reconstructions using nonmarine ostracodes.