When I worked at the science museum near school, one of my jobs was to help man the tide pool touch tank. We had a few different kinds of hermit crabs, some engineer fish, pencil sea urchins, and chocolate chip sea stars, and we had a separate tub that we would put some of the critters in so the kids could touch them. A lot of times, we'd feed them the morning of touch tank days so the sea stars in particular would stay put on their rock (otherwise, they'd roam around the tank), and sometimes we'd be lucky enough to have one of the stars do a backbend off the side and show their digestive process.
 |
| Picture from Frans Xaver on Wikimedia Commons via CC Attribution-Share Alike |
A lot of people would get grossed out, but I enjoyed explaining to everyone that sea stars eat by expelling their stomachs through their mouths, wrapping them around their food, digesting it externally, and sucking the juices back in. Generally they'd be nomming on clams for this process, which tended to gross out the already grossed out even more.
In a
Science Take by the New York Times, researchers have determined the mechanism behind this external digestion process. They knew that a muscle-relaxing neuropeptide was responsible for the expulsion and posited that a counteracting neuropeptide would reverse the process; neuropeptides in the
NG peptide family, which trigger contraction, were tested and proved to retract the stomach.
Such knowledge may be applied in the future to help control sea star predation, as they can take out coral and shellfish populations that are both ecologically and economically important (not to mention protected, in the case of corals). And if it works with sea stars, they might want to extend it to other echinoderms, considering how sea urchins are notorious for taking out marine flora too.
No comments:
Post a Comment