Ocean Observers: Marine Species Will React to a Total Eclipse

Excerpted from an article by Deborah Netburn in the Los Angeles Times:

Across the ocean, an enormous number of animals hide in the deep, dark waters during the day, and then swim upward during the cover of night to take advantage of the food generated in the sunlit part of the ocean.

Jonathan Fram, an assistant professor at Oregon State University, plans to use a series of bio-acoustic sonars to see whether zooplankton in the path of totality will rise in the water column as the sun is obscured by the moon.

Fram, who works as a systems engineer on the Ocean Observatories Initiative (OOI), will retrieve data from six bio-acoustic sonars off the Northwest coast — three that are directly in the path of totality and three that are not. This should allow researchers to see how much the sun has to dim to affect changes in the zooplankton’s movements. The OOI moorings were not designed for the eclipse, but they are located within the path of totality.

Kelly Benoit-Bird, a senior scientist at the Monterey Bay Aquarium Research Institute who is not involved with Fram’s study told the Times, “Scientists have known for decades that changes in light can affect these animals’ migration patterns. For example, most of these deep-water migrants won’t swim as close to the surface as usual during a full moon. Still, a total eclipse provides an ideal natural experiment that can help researchers learn how important light cues are to different critters.”

While viewing a previous eclipse from a boat near the Galapagos Islands, Doug Duncan, director of the Fiske Planetarium at the University of Colorado, Boulder, “saw dozens of whales and dolphins swim to the surface of the ocean five minutes before the eclipse began. They hung out there until five minutes after the eclipse, before returning to the watery depths,” the Times reports.

University of Toledo biology professor Elliot Tramer reported that seabirds on the north coast of Venezuela were affected by a total eclipse that passed through the area in 2008. Brown pelicans and frigatebirds that had been foraging over the water before the eclipse left the bay 13 minutes before totality and didn’t return until 12 minutes after the solar disk was fully revealed. He concluded that although total solar eclipses are short, they can still interrupt normal avian daytime behavior.

A study published in the Journal of Fish Biology in 1998 found that fish also respond to changes in light during an eclipse. After observing reef fish during a total eclipse that swept over Pinta island in the Galapagos, the authors found that daytime fish sought shelter in the reef during totality while nocturnal fish were more likely to leave the cover of their daytime habitats.!