“It’s easy, when you get away from the coast, to think of the oceans as a homogeneous blue. It’s a lot more complex than that,” said biologist Craig McClain of the National Evolutionary Synthesis Center.
McClain and colleagues collected the mud while surveying distributions of seafloor organisms, the lives of which are shaped by “marine snow” — a slow, steady, shower of organic particles that drift down from high in the water column.
Like terrestrial snow, the deep-sea-life-sustaining version doesn’t collect uniformly but gathers in drifts and eddies. In a paper published last year in Marine Ecology, McClain and others showed that, depending on snowfall, seafloor communities could vary wildly in the space of a few feet. In terrestrial terms, it was a bit like finding deserts and swamps separated by footsteps.
In a December Proceedings of the Royal Society B paper, the researchers again looked at seafloor distributions — but this time, rather than surveying one small seabed plot, they took samples from across the Atlantic Ocean.
They found large-scale, trans-Atlantic patterns, somewhat reminiscent of the vast and elegant patterns seen in blooming plankton, but not measured before on seafloors.
“The oceans are not as uniform as we have a tendency to think of them,” said McClain. “When you actually look at the ocean, you find that it’s a mosaic.”
Image: Craig McClain/Deep Sea News