UW study: Climate change linked to longer ‘dead zones’ in lakes
MADISON, Wis. — A newly published study done on Lake Mendota says climate change is linked to longer lasting dead zones.
In the summer, lakes can settle into having two layers of water, a phenomena known at stratification. Warm water is lighter and sits on the top of the lake, while colder water sits at the bottom of the lake.
Dead zones occur because organisms like algae fall to the bottom of the lake during stratification, and while decomposing they use up all of the oxygen in the lower layer. Because the water is separate from the upper layer, no new oxygen is delivered to the zone. This prohibits new organisms to grow in the lake and even kills the living organisms.
UW Limnology researcher Robert Ladwig and his colleagues looked at four decades of data from Lake Mendota to conduct their research.
They found that the warmer the climate gets the more likely that two things will happen: stratification will begin earlier, and algae blooms will become bigger.
This means that dead zones will increase in probability, and could even last longer than they do now. This could ruin many lake ecosystems.
Ludwig said to protect the lakes in Wisconsin using less fertilizer and preventing runoff into lakes helps stop the longer dead zones. Nutrients that run into the lake causes the larger algae blooms. If the runoff can be managed than so can the algae blooms and the dead zones.
“Locally, there’s no way we in Wisconsin can stop global climate change,” Ladwig said. “So the only thing we can do is manage the conditions of our lakes.”
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