Observations and Measurements of Planktonic Bioluminescence in and Around a Milky Sea
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
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The Indian Ocean and Arabian Sea have been observed to exhibit surface bioluminescent displays unparalled in intensity and spatial extent. In July 1985, we conducted bioluminescence measurements in the surface waters of the western Arabian sea during the period of the Southwest monsoon and to identify the causative plakton for those displays. A unique type of bioluminescence display, known as Milky sea, was observed on the ocean surface for 3 days. Luminous dinoflagellates, zooplankton, and bacteria were isolated and tested in a shipboard laboratory photometer system for bioluminescent potential. Their light output values, together with abundance of luminous species present in collected plankton samples, indicated a stimulable bioluminescence field superimposed on a milky sea. The stimulable biouminescence field was dominated by luminescent dinoflagellates, primarily Pyrocystis spp. and Protoperidinium spp. The zooplankton contribution to the overall light budget was estimated at 50 for the samples examined and was dominated at times by euphausiid furcilia and Pleuromamma spp. copepods. Phaeocystis colonies glowed continuously and appeared to act as a substratum for the colonizing luminous bacteria Vibrio harveyi. This bacteria is hypothesized to the source of the luminescent milky sea. Reprints.
- Biological Oceanography