Friday, March 21, 2014

Lake Erie: When It Rains, It Poisons

Harmful algal bloom hits shore of Lake Erie's Pelee Island. NOAA.
Climate change could bring more runoff and toxic algal blooms to Lake Erie.

The news coming out of Lake Erie is rarely good. In short, you can’t swing a dead bass near this southernmost Great Lake without hitting some kind of environmental disaster. But according to scientists at an online seminar yesterday, climate change could unleash even more havoc on this freshwater ecosystem, in the form of huge blooms of toxic algae.

Along with fouling beaches and bullying native species, invaders like zebra and quagga mussels are gobbling up the lake’s beneficial algae. This makes room in the ecosystem for another algae called microcystis, which produces a toxin that poisons the water for fish, humans, and unfortunate dogs alike. To make matters worse, fertilizers containing phosphorous pour into the lake from surrounding farmland, encouraging the growth of algal blooms. And now scientists say climate change is pecking away at the lake’s annual ice sheet. With less ice, evaporation on the lake could increase during the winter and allow algal blooms to flourish longer each year.

That Lake Erie is under attack from all sides is nothing new, of course. Barry Yeoman enumerated the lake’s troubles back in 2011 (see “Lake Erie Deathwatch”). But as we come to understand just how difficult it is to influence global climate policy, local scientists are becoming increasingly worried about what a warmer world will do to already struggling ecosystems such as Erie.

“Overall, Lake Erie is receiving a higher frequency of storms of one inch or greater,” says climatologist Molly Woloszyn. That means climate change isn’t just affecting the amount of water entering the watershed, but also the manner in which it gets there. Heavier rains are more likely to wash away farmers’ fertilizers, flushing them through the watershed and into the lake.

To adapt to these new weather patterns, a recent report from the Ohio Lake Erie Phosphorus Task Force recommends that farmers reduce fertilizer use by 40 percent and adopt practices to prevent agricultural pollution, such as not applying fertilizers when the ground is frozen or when heavy rain is on its way. Additionally, anti-erosion techniques like cultivating crops that keep their root systems intact year-round could help cut down on runoff. Unfortunately, because the task force has no way to enforce these guidelines, any phosphorus reduction would be voluntary.

Nobody wants to bet against an ecosystem that’s been left for dead more than once, but the outlook for Erie is as dreary as ever. Problems as big as climate change force local governments to learn to pick their battles. But if the plan is to curb farm runoff, fend off toxic algae, and improve water quality in this once-great lake all in one swoop, I’d say dive in.

The original post is here.

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