WOLCOTT, TG*; WOLCOTT, DL; KAMYKOWSKI, D; WATERS, L; NC State Univ.; NC State Univ.; NC State Univ.; NC State Univ.: Plankton mimicry: fake dinoflagellates to help understand real red tides.

Our robot plankter has been redesigned to permit study of motile algae as well as zooplankton. Presently it is being trained to behave like a dinoflagellate to elucidate how behavior interacts with physical oceanography in the genesis, transport, and eventual dissipation of red tides. It senses time and environmental variables: depth, temperature, salinity, photosynthetically-active radiation (PAR), and vertical velocity relative to the surrounding water and to the surface. It responds by migrating vertically according to known or theoretical behaviors of the organism under study. In its first field deployments it has successfully migrated according to the programmed profiles, calculated �physiological� variables (photosynthesis, respiration, nutrient uptake, cell C and N pools), and logged environmental and �physiological� data. An integrated GPS receiver, activated during short hops to the surface, has logged positions along the trajectory, obviating the need to follow each unit via its ultrasonic pinger. A VHF radio beacon, encoding the current GPS position, allowed location and retrieval of units from up to 6 km distance. We anticipate full-scale deployments in Gulf of Mexico red tides next year, using behavioral models that allow physiological state, as well as time, light and temperature, to modulate vertical swimming behavior.