Metals and metalloids concentrations in three genotypes of pelagic Sargassum from the Atlantic Ocean Basin-scale

Abstract

Since 2011, the Caribbean Islands have witnessed unprecedented massive stranding of a pelagic brown algal Sargassum spp. inducing damages for coastal ecosystems and economy. By accumulating heavy metals, Sargassum can play a role in contaminant transportation from offshore to the coast. In 2019, three genotypes of Sargassum (S. fluitans III, S. natans I, and VIII) were sampled in seven stations along a 3400 km transect in the Atlantic Ocean. Concentrations of 15 heavy metal(loid)s elements were analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Mean metal concentrations were ranked following descending order: As >Fe > Al > Mn > Cd > Zn > Ni > V > Cu > Cr > Hg. The metalloid As was the most abundant contaminant with a maximum value of 115 ppm, previously observed in the Caribbean area (80-150 ppm). At Atlantic Ocean Basin-scale, metallic element concentrations do not present spatial longitudinal gradients. Genotypes S. fluitans III and S. natans (I and VIII), present differents metal(loid)s contamination distinct patterns.

Keywords: Arsenic; Caribbean Sea; Metalloids; Metals; S. fluitans; S. natans.