A forest fire both destroys and creates. It destroys the plants and animals that live there. But it creates the conditions for a new ecosystem to develop through a process called ecological succession.

Scientists recently reported that a similar process plays out in one of the deepest spots in the oceans. Big blobs of sediments settle on the bottom. That can destroy the organisms that inhabit the region. But the sediments bring nutrients and stir things up in a way that starts a new cycle of life.

The scientists studied sediments from the bottom of the Japan Trench. It’s a long gash in the Pacific Ocean where two of the plates that make up Earth’s crust intersect. The scientists X-rayed the top layers of sediments in samples taken from depths of almost five miles. And they found that a cycle of life played out over and over again.

The cycle begins with a big “pulse” of sediments. It flows down the slopes of the trench, then settles on the bottom. The sediments bring nutrients and churn things up on the sea floor. As the flow ends, organisms burrow into the soft mud. The burrows can be several inches long, and can form straight tunnels, corkscrews, or other shapes.

As these organisms use up the fresh supplies, microbes that prefer low-oxygen environments move in. They attract microbe-eating organisms—some of which dig their own burrows.

Every time a new load of sediments arrives, the cycle starts over—destruction and creation in the ocean depths.

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