For multicellular life—plants and animals—to thrive in
the oceans, there must be enough dissolved
oxygen in the water. In certain coastal areas,
extreme oxygen-starvation produces "dead zones"
that decimate marine fisheries and destroy food
web structure. As dissolved oxygen levels decline,
energy is increasingly diverted away from
multicellular life into microbial community
metabolism resulting in impacts on the ecology and
biogeochemistry of the ocean.