Estimated near‐surface mesoplanktonic bioluminescence in the western North Atlantic during July 1986

Abstract

Mesoplankton samples (retained by 202#x2010;µm mesh) were collected with oblique net hauls from 150 m to the surface along 62°W from 30°N (Sargasso Sea) to 44°30′N (Nova Scotia shelf) in July 1986. The amount of bioluminescence produced by mechanically stimulating individual bioluminescent organisms (ostracods, copepods, cuphausiids) to exhaustion (TMSL) was measured with a shipboard photometry system. The TMSL values combined with individual organism abundances from the net tows provided an estimate of total near#x2010;surface bioluminescent potential. It was greater (11.4 × 1014 photons m−2) in the Sargasso Sea than in the Slope Water north of the Gulf Stream (3.0 × 1014 photons m−2). In the Sargasso Sea, Pyrocystis noctiluca was the major light producer south of 39°N, but became less important between 39°N and 42°N. In Slope Water, north of 42°N, the copepod Metridia lucens was responsible for 90% of the potential near#x2010;surface bioluminescence produced by mesoplankton.