Eutrophication

A major part of our vision is saying goodbye to blue-green algae and ending eutrophication once and for all. But what is eutrophication and why is it such a major issue?

Eutrophication is a phenomenon caused by excess nutrients entering a body of water. These nutrients lead to large blooms of blue-green algae on the surface of the water. This algae, also called cyanobacteria can release toxins into the water that are harmful to humans and wildlife. Even more threatening, an algal bloom doesn't have to be fully formed for these toxins to be present in the water. This can make cyanobacteria extremely difficult to catch early and treat before the problem gets out of hand.

While many people think eutrophication is exclusively a freshwater issue, blue-green algae can also thrive in saltwater environments. This means that almost no aquatic ecosystems are safe from this massive issue. Eutrophication is especially prominent in farming regions, because the nitrogen and phosphorus found in common fertilizers often enters lakes and ponds in the form of runoff. An estimated 40% of the world's lakes were estimated to be contaminated with cyanobacteria. That's over 46 million lakes actively being contaminated by these toxins!

There are several different methods of treating eutrophication, but each comes with its own downside or limitation.

One widespread method that's currently being implemented is a federal restriction to limit the amount of nitrogen and phosphorus that can be in fertilizers. But implementing new laws takes time, and enforcing them is an entirely different issue. While regulations on fertilizers are necessary, they also do nothing to treat the millions of already-existing blooms.

Another solution involves using chemical treatments to help clean the water. Using substances like copper, aluminum, and iron chloride is common, but each of these has its own harmful effect on the wildlife. Fish in ecosystems treated by these substances often suffer from kidney, liver, and gill failure. Another downside to this method is that chemicals are typically only added after the bloom has surfaced, so without a present bloom, there won't be an obvious sign that treatment is necessary.

Some sewer treatment plants have begun offering biological filtering to remove algae from the water supply. However, in rural ponds and lakes not connected to the sewage system, this option is simply not a possibility.

Finally, the National Oceanic and Atmospheric Association has recently developed a method of algal detection that uses satellite imagery to spot large oceanic blooms. This method doesn't do anything to actively treat blooms, however, and it lacks the ability to identify cyanobacterial activity without a large bloom present.

While the toxins produced by blue-green algae are very harmful, there are other effects of eutrophication that also hurt aquatic ecosystems. In order to grow to their massive sizes, algal blooms require a high amount of oxygen. They often use water-based oxygen to meet this need, which leaves little oxygen available for the organisms of the water. Because algal blooms cover so much of a pond's surface area, they often deprive the organisms of the pond of the sunlight they need to survive. This means that subaquatic plants can't properly photosynthesize, which hurts the entire food chain of the ecosystem. Lastly, eutrophication has a negative affect on the pH of a body of water. While lake and pondwater typically has a pH of 9, cyanobacteria raise this value to roughly 10 or 11 on the pH scale. Many aquatic organisms are not capable of surviving in these more basic conditions.