Harmful Algal Blooms

by Sara Grunberg

April 1

Harmful Algal Blooms

At first glance, the aerial view of Lake Erie swirled with green pigment looks beautiful. If you think blue-green algae, also known as cyanobacteria, are just those harmless little plants floating around in ponds and lakes, think again. This plant-like organism is a Harmful Algal Bloom—also known as HABs. These aggressive, fast-growing blooms can quickly turn once-pristine lakes into toxic soup, poisoning people, wildlife, and ecosystems alike. So, let’s dive into this green menace and figure out what’s going on here, why it’s happening, and how we can stop it from turning our waterways into nature’s version of a horror movie.

While not all algae are harmful, when certain species proliferate in excess, they can turn the water green, blue, or red and release toxins that pose risks to human and animal health. Normally, algae are an important part of aquatic ecosystems. They help produce oxygen and serve as a food source for many aquatic creatures. But when certain types of algae decide to multiply uncontrollably—usually triggered by excess nutrients—things go awry.

Now, why do these blooms happen? Well, it all comes down to too much of a good thing. HABs are rapid overgrowths of algae in water, typically driven by excess nutrients like nitrogen and phosphorus. The result is a massive bloom of algae that can choke off oxygen in the water, suffocating fish and other marine life, and in some cases, releasing toxins that can make both humans and animals sick.

These nutrients often come from fertilizer runoff, sewage, and urban pollution. When there’s a surplus of these nutrients in the water, algae can go into overdrive, feeding off the excess and growing rapidly. This on top of increasingly warm lake temperatures due to climate change and it’s basically an algae party. But like any unsupervised party, it’s all fun and games until someone gets sick—or the ecosystem crashes.

Now, let’s take these concepts and dissect them by looking at our local water supply—Lake Erie. Because the Western basin of Lake Erie is very shallow, the water is warm. The watershed around Lake Erie has the least forest land of all Great Lakes watersheds, the most agricultural land, and the second most urban/suburban land, lending itself to an abundance of unfiltered runoff. Consequentially, Lake Erie gets more sediment and nutrients than the other lakes. Since it is the southernmost, shallowest, warmest, and gets the most nutrients, biologically Lake Erie is the most productive of the Great Lakes and more vulnerable to algae blooms.

Unfortunately, this is an issue many of us know from firsthand experience. In 2014, Toledo experienced a major water crisis. Defined as a state of emergency, the HAB on Lake Erie made the city’s tap water undrinkable. Local officials had to issue a “do not drink” advisory to about 500,000 that rendered the water unsafe for consumption, cooking, and even bathing.

The good news is, there are ways we can prevent or at least reduce the damage done by HABs. The first step is addressing the root cause: nutrient pollution. Reducing the amount of fertilizers used in farming, improving wastewater treatment systems, and reducing urban runoff can go a long way in preventing these blooms from happening in the first place. We also need to protect natural filters like wetlands, which help trap excess nutrients before they reach our water bodies. And on the scientific side, researchers are working on better monitoring systems to predict and control blooms before they get out of hand.

While HABs are a serious environmental issue, the good news is that with proper management and action, we can tackle the problem head-on. By reducing pollution, improving water quality practices, and taking care of our ecosystems, we can keep the blooms at bay.

This month’s “call to action” is to contact local government officials to express your concern of harmful algal blooms and why it is essential to protect Lake Erie. Please share successes by emailing Maegen Anders at manders@sistersosf.org.