STUDYING
BIOLUMINESCENCE

Micro Scale
For micro-scale studies we use an intensified video transect technique to identify and map bioluminescent organisms based on the spatial and temporal properties of their stimulated bioluminescent displays. Video data is collected with an intensified camera mounted on the JOHNSON-SEA-LINK submersible and focused on a 1-meter transect hoop. During transects, bioluminescence is mechanically stimulated as organisms come into contact with or pass through the wide mesh (1800 micron) NITEX screen which is stretched across the hoop. We have been developing a data base of identified bioluminescent signatures using a variety of techniques.

By combining micro-scale and fine-scale measurements of bioluminescence we have a rapid means of assessing plankton distribution patterns relative to the physical and chemical variables in the environment. In this study HIDEX-BP profiles made in the Gulf of Maine were used to select depths for submersible transects. A single frame from the intensified video recordings made at each depth indicates the very different displays that were associated with the different peaks of bioluminescence (Widder et al., 1999). Displays at 20 m and 137 m were primarily small clouds of bioluminescence, characteristic of copepods. At 61 m and 98 m dinoflagellate displays were most abundant. Also shown at 61 m is the figure-8 pattern characteristic of lobate ctenophores. At 206 m the cydippid ctenophore, Euplokamis sp., released brilliant clouds of luminescent particles. Each frame shows a field of view 1 m across and within this large field of view we can use the species-specific label of bioluminescence to identify an organism as small as a 50 micron dinoflagellate.