Lake Erie is being invaded by algae that is turning its waters bright green, killing off communities of fish, and seriously injuring the tourism industry.
The algae’s extensive blooming in recent years is due to surges in phosphorus, which is running into the waters from farms and cities, which the algae feeds on.
You can see how much worse Lake Erie is than the other great lakes in the image below from October 2011. The milky blue near the shores of Lake Huron and Lake Michigan is quartz sand and sediment stirred up by strong winds.
You don’t see that in Lake Erie, the smallest of the Great Lakes. The green is the smelly algae:
This 2011 algal bloom was record-setting — three times the size of the largest previous bloom — and triggered an International Joint Commission investigation. Their report, released last month, discussed the particularly hard-hit western end of Lake Erie, where the Maumee River spills into the lake.
While boaters and swimmers aren’t likely to become seriously ill from touching or swimming in the green waters, some may experience “skin irritation….gastrointestinal discomfort and, in very rare but severe cases, acute liver failure if the bloom is ingested,” according to the report. Of all the Great Lakes, only Lake Erie has noted cases of human and dog deaths from harmful algal blooms, said the report.
Algae can produce toxins harmful to fish. Additionally, as algae die, they decompose, using up oxygen supplies in the process that would normally be reserved for the fish. As the shallowest and warmest of the Great Lakes, Erie supports more than 130 fish species, said the report.
The 2011 bloom caused an estimated $US2.4 million dollar loss in Ohio’s recreational fishing industry alone and a $US1.3 million dollar loss to Maumee Bay State Park due to lack of visitors, said the report.
The image below, from 2011, shows the algae’s impact in Pelee Island in Canada, which is East of Maumee Bay and five miles north of the international border:
The commission said the bloom was caused by increased phosphorus runoff from a variety of sources including farm and residential fertilizers, septic tank leaks, pet waste, and storm drains.
One of the most infamous bloom-inducing culprits is known as dissolved reactive phosphorus — popular in certain types of farm fertilizers — the use of which has increased two-fold and is algae’s favourite meal, Don Scavia, director of the University of Michigan’s Graham Sustainability Institute, told the Associated Press.
Roughly 63% of Lake Erie’s watershed is used for agriculture, said the report, which is a main source of these phosphorus-heavy runoffs.
The commission says a 39% decrease in phosphorus levels (from the 2007-2012 average) in the Maumee River — which is Lake Erie’s single largest source of phosphorus — would go a long way to solving the algae problem.
The report also calls for better industrial fertilization practices, such as making sure the fertiliser is directly applied to the soil instead of being trapped on top of ice and snow, which can happen when it is applied in fall and winter.
There is hope. Similar, though less extreme, blooms occurred in the 1960s and 1970s. By decreasing how much phosphorus made it into the lake, the algal blooms were curbed by the mid 1980s. The lake came back from the dead.
While we can’t predict future blooms, the report suggests bigger and badder blooms may keep coming if nothing is done. Climate change could cause more extreme runoff events and warmer water temperatures — conditions ideal for blooms.
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