Lasers Shed Light On The Inner Workings Of The Giant Larvacean

2017-09-12T12:53:07+00:00 May 5, 2017|
New laser technology is allowing MBARI scientists to look into the structure of giant larvaceans — tadpole-like marine animals that are important players in ocean ecosystems. In a recent paper in Science Advances, MBARI researchers described a new method for measuring the flow of seawater through larvaceans and other gelatinous animals. The results will help scientists understand how much carbon dioxide the oceans are absorbing from the atmosphere.

(From — Larvaceans play a significant role in moving carbon from the upper part of the ocean down into the deep sea. They build balloon-like mucus structures called “houses,” which concentrate food by filtering tiny particles out of the surrounding seawater. These particles contain organic carbon, some of which originated as carbon dioxide in the atmosphere.

Over time their filters become overloaded with particles, and the larvacean abandons its house. The discarded houses collapse and sink rapidly to the seafloor, carrying carbon into the deep sea. Once on the seafloor, this carbon is consumed by animals or buried in seafloor sediment. The buried carbon is likely to be removed from the atmosphere for millions of years.

Because giant larvaceans are just centimeters in length, but build houses that can be a meter across, they are a challenge to study. Intact larvacean houses are nearly impossible to collect in a net or jar, or to contain in a laboratory aquarium. Once they drift into a solid net or wall, the houses fall apart.

Instead of trying to build a tank large enough to harbor a giant larvacean and its house, MBARI Postdoctoral Fellow Kakani Katija has been investigating ways to study larvaceans in the open ocean, using a technique called particle image velocimetry (PIV). PIV systems have been used in laboratories for decades to observe and measure complex water-flow patterns such as currents, swirls, and eddies.

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