14 DAY TRIAL // Most people know that being in the heat can be bad for their health, and that is why they usually drink water before they go outside in the Sun, and take some with them as well. But have you ever met a person that drinks about seven liters of water before going out? Of course not, because it's nearly impossible. However, this is how a starfish goes about protecting itself from the heat. Just before it goes out into the low tide, the small creature pumps itself up with cold seawater, which allows it to control and regulate its body temperature, the BBC News reports.
In spite of the highly effective cooling mechanism, researchers say that the starfish could be endangered by a relentless foe – global warming. As the surface temperatures of the oceans increase, the aquatic creatures will need to make more and more efforts to remain cool. This will translate into much less energy going into other processes, such as digestion and respiration, which, in turn, could have devastating consequences, oceanographers reveal.
The sea star (Pisaster ochraceus), also known as the ochre starfish, is indigenous to the intertidal regions located along the Pacific North American coastline. One particularity of this species is that, at low tide, it gets trapped on dry land, under intense sunlight, and needs to wait for the water to rise again, more than six hours later, before it can thermo-regulate once more. American scientists describe in the latest issue of the journal American Naturalist how the starfish manages to regulate its temperature over these long time spans.
“We have discovered a quite novel thermoregulation strategy in the animal kingdom. We found that the weight of the sea stars increased during the days after exposure to high temperature at low tide. The sea stars were not allowed to feed. So this increase can be explained only by an increase in seawater uptake. When sucking up water, the body mass of a sea star increases,” expert Dr. Sylvain Pincebourde says. The scientist worked at the University of South Carolina in Columbia (USC), but now holds an appointment with the François Rabelais University, in Tours, France.
“Because its body mass is now higher, body temperature increases more slowly. The thermoregulatory strategy we have revealed in our study indicates that the sea star is well adapted to such a variable environment,” the scientist concludes.