Small-scale variability patterns of DMS and phytoplankton in surface waters of the tropical and subtropical Atlantic, Indian, and Pacific Oceans

Abstract

High-resolution surface measurements of dimethylsulfide (DMS), chlorophyll a fluorescence, and the efficiency of photosystem II were conducted together with temperature and salinity along five eastward sections in the tropical and subtropical Atlantic, Indian, and Pacific Oceans. Analysis of variability length scales revealed that much of the variability in DMS concentrations occurs at scales between 15 and 50 km, that is, at the lower edge of mesoscale dynamics, decreasing with latitude and productivity. DMS variability was found to be more commonly related to that of phytoplankton-related variables than to that of physical variables. Unlike phytoplankton physiological data, DMS did not show any universal diel pattern when using the normalized solar zenith angle as a proxy for solar time across latitudes and seasons. The study should help better design sampling and computing schemes aimed at mapping surface DMS and phytoplankton distributions, taking into account latitude and productivity.