Enter the lowly larvacean. Larvaceans are small, tadpole-like animals related to the tunicates or "sea squirts" found in tide pools. The "giant larvacean" of the genus Bathochordaeus is only about 50 mm (two inches) long, but is widely distributed, occurring in both the Pacific and Atlantic Oceans. Like most larvaceans, it feeds on tiny food particles in the surrounding seawater.
A giant larvacean lives inside two net-like mucus filters, which are collectively called its "house." The outer filter traps coarse particles, and can be up to one meter (three feet) across. The inner filter is slightly more dense, and traps small particles that the animals eats. The larvacean constantly pumps water through both filters, which typically become clogged after about 24 hours of use. At this point the larvacean abandons its house and swims off to create a new one. The cast-off larvacean house eventually deflates like a punctured balloon and sinks rapidly toward the seafloor, carrying large amounts of detritus as well as tiny animals that colonize the mucus.
MBARI scientist Bruce Robison had observed hundreds of these cast-off larvacean houses (commonly known as "sinkers") while exploring the waters of Monterey Bay using MBARI's remotely operated vehicles (ROVs). After seeing how common sinkers were, Robison wondered if they might be delivering significant amounts of food (in the form of organic carbon) to the deep sea. As he explains, "When it became apparent that sinkers might be important carbon sources, we went around asking other oceanographers if they had seen these things [sinkers] in their sediment traps. It turns out that, although sinkers are relatively common, the odds of a sinker even hitting a sediment trap in the open ocean are extraordinarily small. In addition, sinkers often simply disinteg
Source:Monterey Bay Aquarium Research Institute