By Chris Adams

The videos, shot underwater on a reef off the Oregon Coast, show the impact of “ocean hypoxia,” a phenomenon that means the ocean is starved of oxygen.

The first video shows fish swimming and plants tall and healthy. The second, shot on the same reef during a hypoxic event, shows no fish – at least none alive. Healthy fish swim away, in search of oxygen. All that are left behind are the carcasses of crabs and fish that didn’t escape.

In a session with National Press Foundation fellows, Francis Chan of Oregon State University explained ocean hypoxia, why it is getting worse and what impact it will have on fish populations worldwide.

Chan also studies ocean acidification, the gradual increase in acid levels in the world’s waters; he calls acidification and hypoxia the “evil twins” of climate change.

“When I was new Ph.D. and started work in Oregon, you could ask a room full of ocean scientists, ‘What’s the biggest threat to the oceans?’ and they would say, ‘Sea level rise,’” he said. Now, hypoxia is a major concern – and not just a theoretical one.

“This is something that is happening right now, in U.S. waters,” Chan said. “We are quite concerned.”

Chan talked about the scientific understanding of hypoxia, as well as ways to possibly mitigate it.