17.6 day old moon
91.3 percent lit
April 17, 2019
By Douglas Main
A full moon is looming (click here) —and it will have a big impact on animals, especially those in the ocean.
Recent studies show that many types of animals have biological clocks finely tuned to the cycles of the moon, which drives fascinating and sometimes bizarre patterns of behavior.
Besides revealing hidden aspects of animal life, the research also has implications for better understanding the circadian clocks present in all animals, including humans.
The first circadian clocks evolved in the oceans, so studying them in marine animals can tell us a lot about how they evolved and how they work and interact with each other, explains Kim Last, a researcher at the Scottish Association for Marine Science.Take zooplankton. These tiny animals engage in the world’s largest migration, which takes place every night when they swim toward the surface to feed on algae. These mini-creatures are prey to a many larger animals that hunt by sight. So to avoid predation, zooplankton head for the depths at dawn....
...When the winter moon is full over the Arctic, it stays above the horizon for a handful of days (depending on latitude), and during this time, zooplankton dive to take cover from predators. But while the moon is out, it also rises and sets—and the zooplankton respond, rising and diving over the course of this cycle, which takes 24 hours and 50 minutes....
Zooplankton (click here) include such protozoans as the foraminiferans ; they are found at all depths but are more numerous near the surface. Bacteria are abundant in upper waters and in bottom deposits....
