Salps are free-floating jellyfish that travel the oceans in long, stringy colonies. They prowl the waters searching for phytoplankton and can grow faster than perhaps any other animal. Salps are extremely energy-efficient, as they use the ocean water to propel themselves. Best of all? Their waste product helps the environment because it assists the ocean’s carbon cycle. And now ScienceDaily reports that scientists have discovered that “nature’s perfect little engine” is even more efficient than previously thought.

Salps range from one-half inch to five inches in length, but new evidence shows they can eat food that ranges in size from relatively small to huge. Researchers at the Woods Hole Oceanographic Institution (WHOI) and Massachusetts Institute of Technology (MIT) say salps can eat a much larger and wider range of animals than once thought. This means they are more powerful and “hardier” than previously believed — and consequently, more efficient.

Laurence P. Madin is the director of research for WHOI. As he told ScienceDaily, “We had long thought that salps were about the most efficient filter feeders in the ocean. But these results extend their impact down to the smallest available size fraction, showing they consume particles spanning four orders of magnitude in size. This is like eating everything from a mouse to a horse.”

Experts are excited about these new findings for many reasons. First, it shows that the salp can live where other grazing animals cannot. Since they can eat even the smallest particles, they will survive times of famine. Second, the more they eat, the more they assist the ocean in its carbon cycle. Salps product carbon-packed waste pellets that sink to the ocean’s floor.

Scientist Kelly R. Sutherland, who also worked on the study, explains why this is important. According to Sutherland, "this removes carbon from the surface waters and brings it to a depth where you won't see it again for years to centuries." And less carbon dioxide on the ocean's surface means less carbon dioxide to escape into the atmosphere. This can only help in the fight against global warming.

The salps, which function like mini-filters as seawater and food passes through them, act like vacuum cleaners in the ocean. They exist everywhere but are most common in the waters near Antarctica. And while other populations like krill are on the decline, salps seem to be increasing. It seems now we know why.

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