Impact of physical-biological interactions on spatio-temporal distribution of bioluminescence potential.

Bioluminescence is light produced by a photochemical reaction in organisms. Most bioluminescent organisms in the marine environment generate light in response to mechanical stimulation, like in the wakes of moving ships or other bodies. Bioluminescence (BL) potential is defined as the flash potential measured inside of a chambered pump-through bathyphotometer, which mechanically stimulates organisms to produce light as seawater is pumped through a detection chamber. We have been studying processes that create observed bioluminescent distributions (upwelling, submesoscale dynamics, accumulation of motile species in convergence zones, growth, advection etc.). Our research has demonstrated that during upwelling favorable wind events, a persistent bioluminescence (BL) potential maximum is present in the upwelling shadow area (where surface wind stress is locally weakened by mountain-range sheltering). This BL potential maximum is due to bioluminescent dinoflagellates, which are able to retain their population in the upwelling shadow area, and avoid advection due to their vertical motility. Offshore of the bay, in the area between a cold jet and warm eddy, submesoscale processes facilitate the intensification and development of observed phytoplankton filaments by maintaining the phytoplankton population in the euphotic layer and by supplying nutrient-rich subsurface waters into the euphotic layer. These offshore filaments show high values of observed BL potential and contain bioluminescent species of dinoflagellates and zooplankton. These offshore high BL potential filaments can move onshore during relaxed winds following the upwelling, and be an additional source of inshore bioluminescence.