Distributions of Epipelagic Bioluminescence in the Sargasso and Caribbean Seas

The nature of oceanic bioluminescence and some of the problems associated with its measurement are discussed in this chapter. No present instrument accurately measures the complete bioluminescence potential of the open ocean environment. At night we measured the bioluminescence stimulated mechanically in a pump-through bathyphotometer capable of capturing weakly swimming organisms. Using this instrument, we were able to describe the bioluminescence in the upper 120 m of the northern and southern Sargasso Sea and the Caribbean Sea. In the late summer, more bioluminescent organisms and more stimulated bioluminescence were observed in the northern Sargasso Sea than in the southern part. In the fall, the station at the southern edge of the southern Sargasso Sea near the Antilles and the station in the Caribbean Sea showed the highest flashing rates (i.e., concentrations of bioluminescent organisms). The bioluminescence in the Caribbean was comparable to that in the northern Sargasso Sea. These patterns reflect some of the general oceanographic features of the Sargasso Sea.