Algae Blooms on Lake Erie October 8, 2011 |
Déjà vu all over again, or that’s what it feels like.
This past weekend officials in Toledo, Ohio warned some
500,000 local residents not to drink the public tap water, or for that matter,
use the water for anything. The culprit was a toxin produced by blue-green
algae surrounding the intake pipe for the water treatment plant. The algae is
really a bacteria known as Microcystis aeruginosa.
In recent years blooms of this organism have covered large swathes of western
Lake Erie during the summer.
The toxin is nasty. It causes nausea, vomiting, rashes, eye
and ear irritation. Boiling water does not destroy the toxin.
For people of a certain age, i.e., my age, this harkens back
to the 1970s when Lake Erie and the Cuyahoga River in Cleveland were the poster
children for how to screw up the environment. The Cuyahoga was the river that
infamously caught fire. Lake Erie was more or less a dead sea due to—yes, you guessed it--large algae blooms.
Algae blooms are not a mystery. They are primarily a man-made
event. Warm water + nutrients + microorganism creates explosive growth. In this
case the key nutrients are nitrogen and phosphorus, which enter the lake from
various man-made sources—agricultural runoff, industrial effluent, yard
fertilizer runoff, livestock feedlots, septic systems, and sewage treatment
plants.
In the 1970s and 80s a concerted effort to reduce phosphorus
entering Lake Erie from industrial sources and sewage treatment plants plus mandated
reductions of phosphorus in detergents did the trick. As the phosphorus load in
the lake decreased by two-thirds, the algae blooms diminished. The lake came back
to life.
Now the phosphorus load is going back up. The worst culprit
is the Maumee River which enters Lake Erie at Toledo and drains a large
agricultural region. This strongly suggests that agricultural runoff is the major
contributor. But other factors, including the invasive Zebra mussel, may also
play a role. Point is the current problem is scientifically figure-out-able.
The real question is whether we can muster the political willpower to fix the
problem once we know what to do.
Of course, we can also do nothing and allow Lake Erie
to re-die.
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