The effects of trace metals on global microbial communities: trace metal analysis from the TARA Pacific Expedition

Most trace metals are needed as either active centers or structural factors in marine microbial enzymes and therefore are vital to the marine ecosystem. During the TARA Pacific Expedition, samples were collected in parallel across surface waters of the North Atlantic, North Pacific and South Pacific Oceans for trace metals, metagenomics, microbial cell counts, physiology analyses, and physiochemical analyses. Here we present trace metal (Fe, Zn, Mn, Ni, Cd, Co, Cu, and Pb) concentrations of 246 surface water samples from the TARA Pacific Expedition. Trace metal distributions across the gradients were influenced by various biological, geochemical and physical processes. High concentrations of iron (Fe) were observed in several regions, including in the North Atlantic Ocean and near the South Pacific islands, due to Saharan dust input and marginal sediment input, respectively. We also observed elevated lead (Pb), for example in the North Pacific near southeast Asia, which indicates where anthropogenic sources could be influencing metal concentrations. Furthermore, the data shows inter-basin differences in concentrations for most of the metals, such as the potentially toxic element copper (Cu), which is relatively high in the North Atlantic, perhaps due to dust deposition. There are also intra-basin differences in metal concentrations between oligotrophic and upwelling regions, such as with carbonic anhydrase-utilizing cadmium (Cd), which shows elevated concentrations at the Peruvian coast due to upwelling. Combined with metagenomic and metatranscriptomic data from the TARA Pacific Expedition, this dataset will reveal how different metals drive the metabolism of individual microbes and overall microbial community structure.