It's that time of year again. No, I don't mean time for back-to-school sales, last-ditch beach getaways, or Shark Week re-runs. Instead, I'm referring to the time of year when we're once again reminded just how sick our waterways are.
Every year around this time, we read about massive dead zones and toxic algal blooms infecting large swaths of our nation's inland and coastal waters. The combination of warming water temperatures and fertilizer runoff during the growing season leads to vast areas of lifelessness for many waterways and aquatic ecosystems.
America's rivers and streams flush the excess nutrients that are applied to, or fall upon, our landscape. When these pollutants finally settle out in our estuaries, deltas, gulfs, and coastal bays, they feed a great swirl of life and death. The fertilizers not taken up by crops or land-based ecosystems instead feed algae, which decompose in a process that consumes oxygen and sucks the life right out of everything from the tiniest stream to our mightiest seas.
At the surface, this appears as thick blankets of vibrant green, blue, red, brown, or other colorful algae. In deeper and open waters, like the Gulf of Mexico, this stage of the nutrient lifecycle causes massive dead zones.
Last month, scientists announced that the annual dead zone in the Gulf of Mexico is the largest in history. In an area the size of New Jersey, the water is virtually devoid of oxygen – a circumstance that is devastating to aquatic life and to Louisiana's seafood industry. The federal government tracks the size of the dead zone each year as part of an effort to determine how well current nutrient reduction policies are working. Clearly, they're not working very well.
A thousand miles away, state and federal officials are on alert for a recurrence of toxic algal blooms in Lake Erie. Federal researchers recently predicted that, like the Gulf dead zone, this year's Lake Erie algal blooms might set records.
It's no coincidence, of course, that both of these iconic waters are suffering. The fate of each waterbody is dependent on responsible management of chemical fertilizers and, increasingly, manure from the industrial animal feeding operations that dot the landscape throughout the Mississippi and Ohio River basins.
While state, federal, and academic researchers continue to work each year to predict the timing, location, and severity of these events, scientists are also learning more about just how devastating the impacts of nutrient pollution can be. As the residents of Toledo, Ohio, discovered a few years ago when their drinking water treatment plant had to be shuttered to prevent contamination, algae is not just gross – it's dangerous.
Hazardous algal blooms come in many varieties, and the impact can vary dramatically depending on the species of algae and the species consuming the tainted water. In shellfish and marine mammals that are exposed to these toxins in large quantities, the results are often fatal, and scientists are starting to learn more about the more peculiar impacts, like severe neurotoxic disruptions. These discoveries are important because many of the same impacts are being found in humans that have been exposed to various toxic algal blooms.
While scientists continue to learn more about the mysterious life of algae each year, we certainly ...