They have two small protruding spouts, from which they will squirt water when disturbed, thus justifying their name. Sea squirts are quite common on the rocky coast of New England and much less common on the sandy shores of the Carolinas. It seems obvious they must use chemical defenses. However, that's not really our story. One day it occurred to the two UNC researchers that these particular sea squirts have another problem.
Most sea squirts live underwater, typically anchored to rocks on the bottom.
Tridentata marginata lives on the sargasso seaweed drifting on the surface of the Sargasso Sea . The Sargasso Sea, a vast area in the middle of the North Atlantic Ocean east of Bermuda, lies under the Bermuda High, an almost-permanent feature of the weather map. Winds blow clockwise around the high, as the do around all high-pressure centers, but over the Sargasso Sea, under the center of the high, there is generally very little wind at all. Sailors fear and avoid this area, where ships can be becalmed for weeks. In the calm, warm waters of the Sargasso Sea float huge quantities of a sargasso seaweed, or gulfweed , as it is often called in English.