SPATIAL HETEROGENEITY OF THE BIOLUMINESCENCE FIELD OF THE TROPICAL ATLANTIC-OCEAN AND ITS RELATIONSHIP WITH INTERNAL WAVES

Field research was conducted during a number of cruises (1982-1986) to the western part of the tropical Atlantic Ocean. A survey taken in su mmer of 1985 was selected for detailed evaluation because it consisted of: (1) transects, based on continuous bioluminescence records made w hen the vessel was underway, (2) drift stations with simultaneous meas urements of bioluminescence (110 m depth), temperature, salinity, dens ity and current profiles (1000 m depth) and (3) 4 buoy stations with c urrent and temperature autonomous recorders. Spectra of bioluminescenc e fluctuations obtained from continuous records have a number of peaks , most of which developed at 12 to 13, 8 and 5 km wavelengths, and, in the vertical bioluminescence structure, heterogeneities ranging in si ze from 10 to 50 m were registered. These horizontal and vertical scal es correspond to the scales of the near-inertial gravity waves, which were observed in data from the buoy stations, and vertical current and density profiling. The waves behave as quasi-stationary fluctuations, generating the conditions for aggregation of the bioluminescent organ isms along the horizontal and in the vertical planes. The concept that the origin of fluctuations in bioluminescence is to be found in near- inertial gravity waves also explains the latitudinal effect of the cha nges in variance of the size and dispersion of bioluminescence heterog eneities averaged latitudinally over 5 degrees intervals over the Trop ical and Subtropical Atlantic Ocean.