Water bodies detected from the micropaleontological record (Radiolaria), in surface sediments from the marine bottom of de la Paz Bay, B.C.S., Mexico.

Nineteen surface sediment samples from La Paz Bay were analyzed. It was found that 7 species were the most abundant and also that these species are associated with characteristic water masses in the Bay. Ctenosphaera sp. and Spongotrochus venustum seem to be related with upwelling processes, Spumellina incertae sedis and Euchitonia mulleri are affected by the San Lorenzo channel waters and, Porodiscus sp., Tetrapyle octacantha , and Zigocampe chrysalidium are associated with the water entering from the California Gulf at the north side of the Bay through its principal mouth.