Bioluminescent eddies of the World Ocean.

Abstract

Mesoscale eddies of the ocean (with a characteristic diameter of about one hundred km and a life time span of about several weeks) are habitats of plankton organisms, many of which are bioluminescent. The spatial heterogeneity of bioluminescence of the upper mixed layer associated with the impact of mesoscale eddies is poorly studied. The 45-year historical data set was retrieved, in order to select the bathy-photometric surveys carried out in the form of station grids and transects across eddies. Data from 71 expeditions deployed in 1966-2022 to the Atlantic Ocean, Indian Ocean and Mediterranean Sea basin were analyzed, in order for the spatial heterogeneity of bioluminescent fields to be elucidated across eddy fields. The stimulated bioluminescence intensity was characterized by the bioluminescent potential, which represented the maximal amount of radiant energy emitted in a given volume of water by bioluminescent organisms. The normalized bioluminescent potential over oceanographic station grids exhibited correlation with the eddy kinetic energy and zooplankton biomass (r =0.8, at p=0.001 and r =0.7, at p=0.05, respectively), in a broad range of energy and bioluminescence units (0.02-0.2 m2 s-2 ; 0.4-92.0*10-8 W cm-2 L-1 , respectively). Overall, estimates of bioluminescent potential variability on the mesoscale contribute to the assessment of the multiple-scale variation of the bioluminescent field of the World Ocean.