Deep sea microbes may be key to oceans’ climate change feedback | Howard Lee

Microbe populations make up 11-31% of living matter in the ocean seabed, but decline significantly as oceans warm

Microbes are hardly the poster-children of climate change, but they have far more impact than polar bears on Earth's carbon cycle - and therefore on our climate. A new study published Friday in Science Advances finds that seabed bacteria and archaea (which look like bacteria but have very different genetics and biochemistry) are sensitive to climate. Because their habitat covers 65% of the entire globe, they form a huge part of the biosphere and are important in the regulation of carbon in the deep ocean, which affects long-term climate change.

The microbes in question are packed together in the top 15 centimeters of the deep ocean seabed, like rush hour commuters in a city metro, up to a million times more abundant than in the sunless ocean water, or buried in deeper layers of seabed sediments. Their city-like crowding is fueled by a sparse sordid snow of excrement and microscopic dead bodies from life in the upper ocean, far above them.