Salps are a type of tunicate or sea squirt, small gelatinous creatures that live in the oceans and are chordates, which makes them more closely related to us than they are to the jellyfish they resemble. They can exist either singly or in chains that may contain a hundred or more of the five-inch animals (National Geographic has a great video on YouTube of a long salp chain).

Salps are known to be efficient eaters and in fact, as this older article in Discover points out,

Moving and eating are the same thing for them. As water flows into one open end of the barrel, the barrel contracts, shooting the water out the back and pushing the salp forward. On its way, though, the water passes through an internal net of mucus, sort of like a sleeve lining, that strains out particles as small as bacteria.

(These creatures are so efficient, the article continues, numerous parasites love salps.)

Recent research published this week in the journal Proceedings of the National Academy of Sciences (PNAS), illuminates how impressive and important these little ocean vacuums are.

According to LiveScience,

…The new results show these animals can consume particles that span a huge size range, or about four orders of magnitude, from a fraction of a micrometer to a few millimeters. If sized up that range would be like eating everything from a mouse to a horse, [co-author Larry] Madin said.

And in fact, they prefer the smaller particles. Again from LiveScience:

In the laboratory at WHOI, [lead author Kelly] Sutherland and her colleagues offered salps food particles of three sizes: smaller, around the same size as, and larger than the mesh openings.

“We found that more small particles were captured than expected,” said Sutherland, now a post-doctoral researcher at Caltech. “When exposed to ocean-like particle concentrations, 80 percent of the particles that were captured were the smallest particles offered in the experiment.”

According to Madin, “Their ability to filter the smallest particles may allow them to survive where other grazers can’t.”

Perhaps most significantly, the result enhances the importance of the salps’ role in carbon cycling. As they eat small and large particles, “they consume the entire ‘microbial loop’ and pack it into large, dense fecal pellets,” Madin says.

The larger and denser the carbon-containing pellets, the sooner they sink to the ocean bottom. “This removes carbon from the surface waters,” says Sutherland, “and brings it to a depth where you won’t see it again for years to centuries.”

But wait, there’s more. Co-author Roman Stocker of MIT says that the more carbon that sinks to the bottom, the more space there is for the upper ocean to accumulate carbon, hence limiting the amount that rises into the atmosphere as CO₂.

Thanks, salps!

Image Kelly Sutherland and Larry Madin, WHOI

In 2006, French scientists dug up micrometeorites in Antarctica that appear to have fallen to Earth about 50 years ago. Antarctica seems to be a hotbed for well-preserved meteorites and not just because of the cold.  There is little contamination from terrestrial sources there.

The micrometeorites appear to be from a comet. But it’s the astonishing amounts of two chemicals that is the basis of the researchers’ paper published in the current edition of Science and breaking news on the web today.

Looking at the large amounts of carbon and deuterium the meteorites contained, the scientists hoped to uncover the comet’s origin. While the deuterium could possibly mean it was interstellar, or from outside of the solar system, the scientists concluded that it was from within and possibly from the outer reaches of our solar system.

But that doesn’t answer all of the questions.

Scientific American quotes lead author and cosmochemist Jean Duprat as saying, “One of the main questions we are addressing with these particles is the birth of the solar system, the material out of which the planets are formed.”

Or, as Universe Today puts it, “the meteorites could provide information about the protoplanetary disk that formed our solar system.” And to go even further, New Scientist says that “the cosmic dandruff could help explain how the carbon needed for life wound up on Earth.”

An exciting discovery, to be sure, that may hold many future answers.

Image courtesy of J. Duprat CSNSM-CNRS