Lake Okeechobee cyanobacteria bloom 8-30-21. Photo by Ralph Arwood. First shared on Facebook by the Calusa Waterkeeper.

Last week the U.S. Army Corps of Engineers gave us some “homework.”

At the end of an Aug. 25 meeting on the proposed new Lake Okeechobee System Operating Manual — LOSOM — the Corps asked participants to think about how much blue-green algae is too much.

Specifically, the Corps asked what “indicators” might signify that poor water quality or algae blooms on Lake Okeechobee are “significant enough” to allow water managers to consider taking action?

And if so, what should water managers do to reduce the risk to public health and the environment?

The answers should be obvious to anyone who cares about our estuaries, our marine life — and human life, too.

Any blue-green algae blooms that produce cyanotoxins are by definition “harmful algae blooms.” And we should not be debating how much harm is acceptable.

The mere presence of harmful algal blooms on Lake Okeechobee where microcystin exceeds the recreational limit of 8 parts per billion should be the “indicator,” and must be enough to compel water managers to keep the floodgates closed, and prevent the blooms from entering the St. Lucie or Caloosahatchee estuaries.

Once in the estuaries, the blooms, fed by nutrients in local basin runoff, have a tendency to explode. The lack of sunlight can spell doom for fragile seagrass; it can harm or kill marine life.

But that’s not all. In Martin County, on Florida’s East Coast, there have been several reports of dogs that became seriously ill after ingesting blue-green algae. Some died.

And the federal Environmental Protection Agency itself acknowledges that “there is evidence of an association between liver and colorectal cancers in humans” and toxic blue-green algae.

So tell the Army Corps: Our homework is done.

Any toxic algae is too much toxic algae. And minimizing the amount allowed into our estuaries should be among the Corps’ highest priorities.