Ocean's Tiny Carbon "Vacuum Cleaners" More Important to Carbon Capture Than We Thought
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If you're a beach goer, you might recognize those little crystal- clear blobs that often wash up on the sand in the mornings as salps. While often mistaken for jellyfish, they're actually the ocean's "vacuum cleaners," sucking up all kinds of particles as food and excreting carbon-rich pellets that sink to the sea floor. Researchers know that the fairly benign creatures are actually quite important for carbon capture and storage in the oceans, but recent discoveries on what they eat show that their role is even more important than previously thought.Live Science writes that researchers, including Larry Madin, director of research at Woods Hole Oceanographic Institution in Massachusetts, state "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, Madin said."
This means that salps are even more efficient ocean cleaners than previously thought -- though they're such incredible helpers for carbon capture and storage that they've made their way into potential schemes for boosting their growth in order to store more carbon in the oceans and even the possibility of becoming the source of carbon capture credits for businesses, according to the Woods Hole Ocean Institute.
Until now, it was thought the 1.5-micron-wide holes in the mesh meant only particles larger than that got captured, while smaller particles would slip through the mucus net. (For comparison, the diameter of a human hair is about 100 microns.)
But a mathematical model suggested salps somehow might be capturing food particles smaller than that, said study researcher Kelly Sutherland, then working on her Ph.D. at MIT and WHOI.
"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."
By being such efficient eaters, salps can survive in the open ocean where larger food is scarce. Additionally, salps are so effective, and abundant, that they impact the ocean's biological "pump" and play a big role in the carbon cycle -- and potentially climate change.
At least one company, Atmocean, has called for stimulating phytoplankton blooms by circulating nutrient-rich water from the deep up to the surface, in order to stimulate the proliferation of salps, which would in turn stimulate the capture of carbon from the water. While not as controversial as adding fertilizer to the ocean to encourage phytoplankton blooms, some objections include that the salps could become a hazard to shipping and marine life.
Regardless of whether humans assist, salps seem to do an amazing job of filtering out particles from the ocean's surface waters are sending carbon to the sea floor.
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