Eastern boundary current systems are
among the most productive large marine
ecosystems in the world. Their productivity
arises from wind-driven upwelling of
nutrient-rich water into the photic zones of
coastal oceans and supports 20% of global fishery
yield (1). Upwelling also transports oxygenpoor
waters onto productive continental shelves,
where respiration can further reduce watercolumn
dissolved oxygen (DO) content and
thus subject coastal ecosystems to the risk of
hypoxia or anoxia.