ABSTRACT

Living radiolarians, planktonic foraminiferans and pteropods have been collected from the waters of the Gulf of Mexico and adjacent seas using Nansen closing nets, DUCA high speed plankton nets, and water bottles. These samples included other shelled microplankton (diatoms, dinoflagellates, silicoflagellates, etc.), non-shelled microplankton (bluegreen algae, dinoflagellates, etc.) and larger plankton (e.g. copepods, chaetognaths). Radiolarian, planktonic foraminiferan and peteropod species compositions, diversities and densities were compared with those of other plankton, and were related to physical and chemical oceanographic parameters. Our studies suggest that certain radiolarian, planktonic foraminiferan and pteropod species may be nannoherbivores, bacterivores, detritivores, and/or associated with symbiotic algae and may be characteristic of eutrophic, mesotrophic or oligotrophic conditions. This information can be applied to studies of the fossil record for finer resolution of paleoecological conditions, (e.g. paleoproductivities) and for inference of the presence and nature (abundance and diversities) of certain non-fossilizable planktonic components.