By Mark Holtsberry

Education specialist

Paulding SWCD

All or most of us have read where Lake Erie’s toxic algae is supported by commercial farm runoff, animal manure, sewage spills, faulty septic tanks and other major sources of nutrients responsible for putting much of the excessive phosphorus and nitrogen in the water.

Now hold on to those horses! Great Lakes scientists are now probing deeper into the weeds on this issue. They are finding that invasive species and climate change also foster algal growth. Invasive species and climate change don’t cause algal blooms, but they worsen them.

I find it amazing that the bombardment of the public with information, gets everyone in a frenzy and then wants to assign blame, even though science doesn’t work that way. Scientists concluded that western Lake Erie has been primed for algal blooms by a number of factors beyond spring time phosphorus inputs and warm summer months.

Western Lake Erie’s algal blooms, which reappeared in 1995 after a 20-year absence, have consistently grown bigger and stronger since 2002. The finding factor is that Lake Erie indeed gets too much phosphorus and that factor is not the trend’s only explanation.

Now, take invasive species. For a while, all you heard was zebra mussels. When was the last time you, yourself have heard any talk of zebra mussels? There are several scientists who believe invasive mussels selectively spit out microsystis, the most dominant form of toxic algae in western Lake Erie.

They also believe that the mussels excrete most of the phosphorus they take in because they have trouble digesting it. They are fussy eaters, but they filter what they eat. They eat tiny organisms, plant particles, and the many healthy productive forms of algae known as diatoms that support the food chain for native fish.

Invasive mussels also aren’t fond of phosphorus. Their bodies absorb it if they have a nutrient deficiency. But there’s so much phosphorus in the lake now that they excrete most of what they ingest. An individual thumbnail-sized mollusk’s impact may seem insignificant, but when billions colonize a lake bottom, their effects may create imbalances that make it easier for algae to grow.

Climate change is often characterized by drama, a greater propensity for floods, droughts, hurricanes and violent weather. Ohio, for example, has had warmer winter nights for nearly four decades. That has kept Lake Erie ice from forming as quickly and as often most winters, with last winter’s polar vortex invasion of arctic air creating a notable exceptions. A report proposes a more subtle climate change impact, one that has gone largely unnoticed but played into more algal growth: longer periods of calm winds between those violent summer storms.

Algae thrives in warm, nutrient-rich water, but especially when calm water allows mats to form. Identifying other contributing factors and understanding the roles they play in priming Lake Erie for algal growth doesn’t mean they will be fixed immediately, if ever.

The U.S. and Canadian governments have tried for decades to slam the door on invasive species, with limited success. Resources that had been focused on quagga and zebra mussels has shifted to Asian carp. Land based invasives like the emerald ash borer have gotten eradication efforts funded by the U.S. Department of Agriculture and other agencies because of that beetles’s devastation of highly valuable commodities from ash trees across North America.

Climate change is a global problem with myriad political obstacles. Scientists agree that even if the world came to an agreement to reduce emissions, it would take years to have a positive impact on the Great Lakes region.