Metagenomic analysis reveals global-scale patterns of ocean nutrient limitation.

Nutrient supply regulates the activity of phytoplankton, but the global biogeography of nutrient limitation and co-limitation is poorly understood. adapt to local environments by gene gains and losses, and we used genomic changes as an indicator of adaptation to nutrient stress. We collected metagenomes from all major ocean regions as part of the Global Ocean Ship-based Hydrographic Investigations Program (Bio-GO-SHIP) and quantified shifts in genes involved in nitrogen, phosphorus, and iron assimilation.

Global ocean methane emissions dominated by shallow coastal waters.

Oceanic emissions represent a highly uncertain term in the natural atmospheric methane (CH) budget, due to the sparse sampling of dissolved CH in the marine environment. Here we overcome this limitation by training machine-learning models to map the surface distribution of methane disequilibrium (∆CH). Our approach yields a global diffusive CH flux of 2-6TgCHyr from the ocean to the atmosphere, after propagating uncertainties in ∆CH and gas transfer velocity.