Giant larvaceans, a type of zooplankton, are the key to the so-called biological pump. This is a process whereby organisms in the ocean transport carbon from the atmosphere into the deep sea, where some of that carbon is sequestered.
Capturing and sequestering carbon help to mitigate global climate change, so we and every other species on the planet benefit from the ocean filtration talents of these tiny creatures every day of our lives.
“We have estimated that as much as a quarter of the organic carbon transported to the deep bottom of Monterey Bay comes from discarded giant larvacean houses,” Robison said, adding that giant larvaceans are also located in oceans across the world.
He and Katija explained that giant larvaceans first make the rudimentary filtration “house” by excreting mucus from a series of cells located on its head.
“At some point in the build process, the larvacean starts moving its tail in a specific fashion, where we suspect the animal is forcing fluid through the house rudiment, and effectively blows up the rudiment like a balloon,” Katija said.
The house is then ready for action, filtering phytoplankton and other organic particles. These materials stick in the mucus house for digestion. When the filtration system fills up with waste matter, the entire nutrient-rich house is discarded and sinks to the sea floor. There, it provides a source of food for deep-sea animals. Giant larvaceans at that point may swim to another location, prior to building another house, in order to start the process all over again.