Meet the Salps

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Some headlines warrant closer inspection. In this case, it was a July 8 story in the Los Angeles Times: “Sea Critters’ Feces Clean Air, Study Says.”

OK, I’ll bite. For those of us concerned about global warming and organic living, we’ll take our environmental solutions any way we can get them.

Scientists at the Woods Hole Oceanic Institution (WHOI) in Woodshole, Massachusetts, have been studying transparent jellyfish-like creatures called salps, considered minor players in the ocean food chain. But salps may be more important to the fate of greenhouse gas carbon dioxide than previously thought.

In the May issue of Deep Sea Research, scientists reported that salps—about the size of a human thumb and swarming by the billions in ocean “hot spots”—may be transporting tons of carbon per day from the ocean surface to the deep sea, thereby preventing it from reentering the atmosphere.

Salps feed on phytoplankton, tiny marine plants that consume carbon dioxide. Other sea life eats phytoplankton, but most of it returns to the ocean when these animals defecate or die.

WHOI biologist Dr. Laurence Madin, along with Dr. Patricia Kremer of the University of Connecticut’s Department of Marine Science and other colleagues, have repeatedly found that one particular salp species (Salpa aspera) multiplies into dense swarms that last for months. One swarm, in fact, covered 38,600 square miles of sea surface, consuming up to 74% of microscopic carbon-containing plants from surface waters. Their sinking fecal pellets transported up to 4,000 tons of carbon per day to deep water.

“Salps swim, feed and produce waste continuously,” Dr. Madin says. “They take in small packages of carbon and make them into big packages that sink fast.” (Indeed, salp fecal pellets sink as much as 3,280 feet a day.)

As the researchers concluded, if salps are an oceanic “dead end,” which other marine animals avoid eating, they can send even more carbon to the deep. This enhances the transport of carbon away from the atmosphere.

You go, salps!

WHOI photo by Dr. Laurence Madin

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