学进去

The sunflower sea star has been listed as a critically endangered species following a groundbreaking population study led by Oregon State University (OSU) and The Nature Conservancy.

“These giant sea stars used to be easy to find and were a hit with divers. Unfortunately, your chances of finding one now are next to nothing in most of the areas near the United States—this listing is one step to extinction—and I don’t think they’re coming back without help,” said OSU’s Sarah Gravem, a research associate in the College of Science and the lead author of the study.

Populations of the sunflower sea star suffered dramatic crashes because of a marine (海洋的) wildlife epidemic event, which began in 2013. Scientists used more than 61,000 population surveys from 31 data sets to calculate a 90.6% decline in the sunflower sea stars and estimated that as many as 5.75 billion animals died from the disease, whose cause has not been determined. Moreover, the research showed no sign of population recovery in any region in the five to seven years since the event.

Sunflower sea stars are a key catcher of purple sea urchins (海胆) and the sea star decline has helped the increase in the urchin population in many regions. Too many urchins are linked to a decline in kelp forests（海藻林) already facing pressure from marine heat wave events, making the future uncertain for ecosystems that provide habitat for thousands of marine animals and help support coastal economies.

“Because most people are not out in the ocean every day, we don’t realize how much it’s being changed and impacted by humans. We need to think about how to keep our ocean healthy. While reducing the release of carbon dioxide is the most pressing need, rebuilding key catcher populations, like the sunflower sea star, can be an important piece of the puzzle too,” said study co-author Sara Hamilton, a Ph. D. candidate in the OSU College of Science.