Churning Krill May Bring Up Nutrients From Ocean Floor

Swarms of tiny shrimp-like crustaceans known as krill could have a big impact on ocean life by churning the waters and bringing nutrients from the depths up to the surface.

The discovery also suggests that sea life could contribute to mixing gases in the ocean. This might influence how gases such as carbon dioxide, linked to global warming, get trapped underwater.

The windswept surface layers of the open seas can teem with life, but scientists could not completely explain why, since predictions suggested not enough nutrients rise up from the abyss below to account for such abundance.

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The researchers, from the University of Victoria in British Columbia, investigated swarms of krill in Saanich Inlet, a fjord on Vancouver Island.

The crustaceans migrate to the surface daily as night approaches and retreat downward as day breaks.

Over the course of three dusks and two dawns, using data gathered in boat expeditions, the researchers discovered that in the roughly 10-minute bursts in which the krill migrated, they drastically increased surface turbulence.

"I was initially skeptical that biologically linked turbulence could be significant. I was surprised at just how large it could be," researcher Eric Kunze, an ocean physicist, told LiveScience.

These findings suggest krill and other sea life could prove critical in bringing nourishment up from the ocean depths, which are loaded with nutrients released by surface organisms that died and sank to the bottom.

"The question now is how frequently and how significant any biologically linked turbulence really is," Kunze said.

The most likely other animals to generate large amounts of ocean turbulence are roughly inch-sized creatures that travel together in large schools or swarms, he speculated, such as anchovies, sardines, herring or squid.

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