Tackling Low Oxygen In An Oregon Lake

Oct 20, 2019
Originally published on October 20, 2019 2:44 pm
Copyright 2019 Oregon Public Broadcasting. To see more, visit Oregon Public Broadcasting.

LULU GARCIA-NAVARRO, HOST:

Many lakes in the United States have serious water quality problems, like algae blooms, low oxygen levels and fish populations dying out. Now, a research team in Oregon is testing out a way to get more oxygen into lakes that need it, as Jes Burns of Oregon Public Broadcasting reports.

JES BURNS, BYLINE: You never suspect on a whisper-still morning with the mountains and marsh reflecting off the water, but Upper Klamath Lake is a tough place to be a fish. Fish can't survive unless there's enough oxygen in the water to breathe through their gills. And the oxygen levels here in Upper Klamath Lake can drop extremely low, especially in the summer. About the same time of year, two endangered species of fish vanish.

MASON TERRY: The juvenile sucker - they're dying off.

BURNS: Mason Terry is a renewable energy professor at the Oregon Institute of Technology in Klamath Falls. The endangered fish - the shortnose and Lost River suckers - used to be common in Upper Klamath Lake and an important traditional food source for local tribes. Now virtually none are surviving their first year. When Terry learned that low oxygen is one of the suspected reasons the endangered suckers aren't surviving, he had an idea.

TERRY: Why don't we just do what they do in fish ponds or in your aquarium? Why don't we just try and bubble some air down in there and see what happens, see if there's just a little boost to affect this one factor that might be a cause of their mortality?

UNIDENTIFIED PERSON #1: One, two, three. Not too far...

BURNS: Terry's renewable energy students at OIT drag a floating solar panel raft about as large as a single-car garage out of the lake and onto the boat landing at Rocky Point. This is the final assembly site.

(SOUNDBITE OF POWER TOOLS RUNNING)

IAN RILEY: Let's just grab the next battery and bring it up here since it's going to be the most annoying thing to do.

BURNS: Ian Riley (ph) hooks up a battery to the solar panels. The panels will run two compressors that will push air, with all the oxygen it contains, down into the lake. U.S. Fish and Wildlife biologist Josh Rasmussen works on sucker conservation in the Klamath Basin. He says putting an aeration system in an area of the lake where juvenile suckers are often found could benefit the fish.

JOSH RASMUSSEN: It's a way to provide an area for the suckers to get out of the bad water quality and at least have somewhere to hide until things get better.

BURNS: Upper Klamath Lake isn't alone in having water quality issues related to low dissolved oxygen. The chemistry of lakes worldwide has been altered by human development and agriculture.

Ken Ashley, a lake aeration specialist at the British Columbia Institute of Technology, says the problems are only going to get worse with climate change.

KEN ASHLEY: The effects of the low oxygen are going to get magnified, and there's going to be more algal problems and more fish kills and poor taste and odor problems. And there'll be more demand to do something about it.

BURNS: When the temperature of water on the surface rises, it prevents oxygen from getting to lake bottoms. Ashley says aeration can be a solution.

ASHLEY: Yeah, it's a growth industry, unfortunately.

BURNS: The students put final touches on the system and drag the solar raft back into the lake. And with the push of a button...

(SOUNDBITE OF COMPRESSOR RUNNING)

BURNS: ...The compressor comes to life. The air hose draped in the water appears to sparkle as air is pushed through thousands of tiny holes.

UNIDENTIFIED PERSON #2: Bubble, bubble.

BURNS: It'll be next year before they know if this aeration system works - when fish counts reveal if any Upper Klamath Lake suckers survive past their first birthday.

For NPR News, I'm Jes Burns in Klamath Falls, Ore.

(SOUNDBITE OF EL TEN ELEVEN'S "FANSHAWE") Transcript provided by NPR, Copyright NPR.