Warming seas may cause more disease, Cornell researchers say.

Sick and dying sea star

Co-authored by Erica Cirino

It’s June 2013: A group of park rangers are walking down a peaceful strip of shoreline in Washington State’s famous Olympic National Park when they spot an alarming sight: dozens of shriveled, gooey-looking purple and orange sea stars trying to cling to a rock.

There’s something wrong, but the rangers are not quite sure what. And little do they know the problem is about to get much, much worse.

Since those first sick sea stars were found in Washington, millions more have been wasting to death all along the West Coast of the U.S., from Alaska to Baja California. A sea star disease epidemic of unknown magnitude decimated up to 90 percent of sea star populations in some parts of the Pacific Northwest between 2013-2014, and, while the epidemic has since slowed, sea stars are still dying.

Sick and dying sea star. Credit: Oregon State University.

Recently, researchers have determined a virus causes the so-called sea star wasting disease. But just this month researchers associated with Cornell’s Ecology of Infectious Marine Diseases Research Coordination Network (EIMD RCN) have discovered why the virus had spread so rapidly and infected so many sea stars, especially during the 2013-2014 period: increased ocean temperatures.

“Temperature can be an incredible driving force for disease,” says Dr. Maya Groner, postdoctoral research associate at Virginia Institute of Marine Science and an author of the study. “This study emphasizes just how important temperature events like El Niño and climate change are when it comes to influencing disease.”

To learn more about how higher temperatures affect sea stars, they collected data on ochre sea star populations and ocean temperature at 16 sites in the Pacific Northwest from December 2013 to July 2015. They also carried out laboratory experiments on sea stars that investigate how —> Read More