ABSTRACT
Coastal systems are highly productive areas for primary productivity and ecosystem services and host a large number of human activities. Since industrialization, metal micronutrients in these regions have increased. Phytoplankton use metals as micronutrients in metabolic processes, but in excess, had deleterious effects. In coastal systems, picoeukaryotes represent a diverse and abundant group with widespread distribution and fundamental roles in biogeochemical cycling. We combined different approaches to explore picoeukaryotes seasonal variability in a chronically metal polluted coastal area at the south-eastern Pacific Ocean. Through remote and field measurements to monitor environmental conditions and 18S rRNA gene sequencing for taxonomic profiling, we determined metal chronic effect on picoeukaryote community's structure. Our results revealed a stable richness and a variable distribution of the relative abundance, despite the physicochemical seasonal variations. These results suggest that chronic metal contamination influences temporal heterogeneity of picoeukaryote communities, with a decoupling between abiotic and biotic patterns.