Turning Great Lakes to Toxic Soup
April 5, 2013
Video above would make good background music while reading this post.
One of the signal moments at the birth of the environmental movement came when the Cuyahoga River, a tributary of Lake Erie in Cleveland, caught fire. The river which runs thru a heavily industrialized district, was said to be so thick with pollution that rats were seen walking across it.
I was working as a deckhand on Great Lakes freighters a few years later – long after the fires were out – but I remember passing thru this area at night, on the way to drop off taconite pellets from Duluth at a steel mill. It made one think of a Bosch landscape.
The visuals of water bursting into flame brought home the reality of pollution’s effects in a visceral way to a generation of Americans.
Now the Lord can make you tumble
And the Lord can make you turn
And the Lord can make you overflow
But the Lord can’t make you burn
Burn on, big river, burn on
Burn on, big river, burn on
Now, with exacerbation from climate change, invasive species and development pressure, the Lakes are under threat as they have not been since that fire on the water.
It was the largest algae bloom in Lake Erie’s recorded history — a scummy, toxic blob that oozed across nearly one-fifth of the lake’s surface during the summer and fall of 2011. It sucked oxygen from the water, clogged boat motors and washed ashore in rotting masses that turned beachgoers’ stomachs.
It was also likely an omen of things to come, experts said in a study released Monday. The warming climate and modern farming practices are creating ideal conditions for gigantic algae formations on Lake Erie, which could be potentially disastrous to the surrounding area’s multi-billion-dollar tourist economy. The shallowest and southernmost of the Great Lakes, Erie contains just 2 percent of their combined waters but about half their fish.
According to the report, which was compiled by more than two dozen scientists, the 2011 runaway bloom was fueled by phosphorus-laden fertilizers that were swept from corn and soybean fields during heavy rainstorms. Weak currents and calm winds prevented churning and flushing that could have short-circuited its rampant growth.
The combination of natural and man-made circumstances “is unfortunately consistent with ongoing trends, which means that more huge algal blooms can be expected in the future unless a scientifically guided management plan is implemented for the region,” said the report’s lead author, Anna Michalak, of the Carnegie Institution for Science.
The U.S. and Canada limited the use of phosphate laundry detergents and cracked down on Great Lakes pollution from industry and municipal sewage systems four decades ago. Those policies led to a drastic algae drop-off in Lake Erie, which had been declared all but dead. But algae began creeping back in the mid-1990s, and the blooms have gotten progressively bigger.
They consist largely of blue-green strains that are poisonous and cause skin irritation. Measurements in 2011 found that concentrations of a liver toxin they produce were hundreds of times higher than levels approved by the World Health Organization for drinking and recreational waters.
The lake’s algae cover was about 90 percent smaller during drought-stricken 2012. But the scientists analyzed computer models and concluded that as the planet warms over the next century, weather that fueled the 2011 mega-bloom may become “the new normal,” Michalak said. The report noted that storms generating more than an inch of rain could happen twice as often, and that wind speeds are dropping.
“Lake Erie was famously declared dead at the time,” said co-author Don Scavia, an environmental engineer at the University of Michigan, in an interview. But in the following decades, strict controls on sewage treatment plants reduced pollution and allowed the lake to recover.
Then came torrential rains in May, 2011, including a storm that dumped 2 inches of water on the region in 24 hours. Fertilizer from thousands of square miles of corn, soybean and wheat fields was flushed into the lake, and algae literally ate it up.
The rains alone wouldn’t have caused such a problem, Scavia said, but starting in the 1990s, several changes in farming practices left more fertilizer on top of the ground. One was the increasing application of fertilizer in the fall, where it would sit on the frozen fields through winter, ready to go to work as soon as crops began sprouting in spring. Another was an increase on the acreage devoted to corn, a fertilizer-intensive crop — especially over the past few years as the federal government encouraged the use of corn ethanol to replace gasoline.
Such downpours are expected to come more often as the world warns: a warmer atmosphere can hold more water vapor, but it also has more to dump during rainstorms. In fact, scientists have already seen both dry spells and heavy rains increase across the globe, and climate models generally agree that this so-called hydrological cycle will continue to become more extreme. “If you combine the changes in farming with the changes in frequency and intensity of severe rains, we think those things are conspiring to make algae blooms worse,” Scavia said.
A vast plain of poisonous green slime stretching to the horizon, bobbing gently on the waves – that was the view of Lake Erie from Cleveland just a couple years ago. It could become a permanent feature if humans don’t scramble to do something about it.
Take a closer look at the boxed-in area in the image below (larger version), captured by NASA’s Aqua satellite in October 2011:
That’s toxic cyanobacteria swirling in the lake waters north of Cleveland. At the time, this slippery stuff covered nearly one-fifth of Erie’s surface, becoming the biggest bloom in the lake’s recorded history. It looked and smelled awful, turned fishing into a hook-detangling nightmare and killed untold numbers of marine creatures by hypoxia.
Worse, the algae’s loaded with foul substances harmful to the heart, blood and skin of many creatures. A dog that ingests one byproduct called microcystin can curl up and die within hours. (In humans it can cause flu-like symptoms, just in case you’re about to eat a bowlful.) The algae might also cause fish to change sexes.
Who’s to blame here? The likeliest culprit is the agricultural industry with a helping hand from global warming, according to researchers at the Carnegie Institution for Science. The scientists conducted a detailed postmortem on the 2011 muck-up using satellite imagery and computer models. As in past years, the process began with farmers spreading phosphorus-based fertilizer in the fall to prepare for spring planting. Because of ideal growing conditions, they were especially fertilizer-happy in the autumn of 2010.
Much of this fertilizer was then washed into the lake by rain, where it acted as a “nutrient load” (aka dinner) for a legion of tiny microorganisms. The river washing was especially intense in May 2011, because a number of massive storms swept great amounts of sediment into Erie. The algae was not only well-fed but encouraged to grow by warmer temperatures and a weak water circulation that kept the stuff near the sunny surface. The result was a bumper year for algae farmers, which might actually become a thing in the future if the algae-based biofuelindustry ever gets off the ground.
You can see the growth happening in this series of NASA shots starting in June 2011 (top left), where the swollen rivers are dumping solids into Erie’s western basin. The algae quickly covers much of the lake, resulting by October (bottom right) in contaminated water that resembles that ancient Ghostbusters‘ Ecto Cooler drink: