Meeting Abstract
The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet remains one of the least explored. Little- known marine organisms that inhabit midwater have developed life strategies that contribute to their evolutionary success. Larvaceans (Class Appendicularia) are found throughout the world’s oceans and affect food webs across trophic levels via elaborate mucus feeding structures they create. Larvaceans swim tethered to their mucus house, forcing fluid and particles through filters that eventually lead to their mouth. Once filters become clogged, the house structure is abandoned, sinks, and eventually the particle-rich structure reaches the seafloor. It is estimated that larvaceans are responsible for the deposition of a third of the particulate that reaches the seafloor in Monterey Bay. Despite having such an important ecological role, little is known about the structure and function of giant larvacean (Bathochordaeus stygias) houses. To address this need, we developed DeepPIV, an instrumentation package that incorporates a high-powered, continuous laser and optics, which is deployed on board remotely operated vehicles (ROVs). This instrumentation enables investigation of various biological and physical phenomena from the surface down to 4000 m. Using DeepPIV and image processing algorithms, we are able to reveal the structure of mucus houses as well as filtration rates and flow directions within houses. These quantitative measurements are used to elucidate how these mucus structures function and contribute to carbon flux in midwater regions of the ocean.
