raPid research on automated Plankton identification

When Victor Hensen deployed the first true plankton net in 1887, he and his colleagues were attempting to answer three fundamental questions: What planktonic organisms are present in the ocean? How many of each type are present? How does the plankton’s composition change over time? Although answering these questions has remained a central goal of oceanographers, the sophisticated tools available to enumerate planktonic organisms today offer capabilities that Hensen probably could never have imagined. Nets still remain the central instrument in our plankton sampling toolbox. But at the present time, it is not uncommon to have computer-controlled underwater vehicles equipped with multiple nets or cod-ends that can be flown along precise trajectories while transmitting real-time environmental data and system telemetry to a surface ship (see Wiebe and Benfield, 2003). In addition to nets, pumping systems bring water to the surface, where plankton from different depth strata can be filtered out. The most dramatic development in plankton survey technology has been the emergence of cameras capable of imaging the contents of defined and generally undisturbed volumes of water. These imaging systems provide nearly continuous records of fine-scale distributions of plankton from centimeterto basinwide volumes. Plankton-imaging systems pose new challenges to studies of aquatic biota. In this paper we summarize the development of plankton-imaging systems, advances in extracting useful information from image data sets in a timely manner, and the most pressing issues that must be resolved to further advance this field of study.