Massive Algae Blooms May Destroy Lake Erie, Threatening Aquatic Wildlife

The massive algal bloom in Lake Erie may be the new norm, unfortunately. New research reveals that unless agricultural policies change, the lake will continue to experience extreme blooms that can cause devastating consequences for aquatic wildlife.

In 2011, perfect conditions caused an algal bloom that became a new record for the area. Long-term agricultural practices followed by weak lake circulation and warm temperatures created a scenario where the algae thrived.

Fresh water algal blooms in general result when excess nutrients, such as phosphorus and nitrogen, enter a body of water. In the case of Lake Erie, these nutrients were the result of runoff from fertilized agriculture in the surrounding area. The phosphorus and nitrogen helped encourage the unusual growth of algae and aquatic plants. Eventually, these plants and algae die and the decomposers that feed on the plant material use up the oxygen in the lake. This causes a scenario where the oxygen in the water is too low for aquatic life to live.

In order to conduct their study, the researchers combined sampling and satellite-based observations of the lake with computer simulations.  They found that while the bloom began in mid-July, it had expanded to over 1,930 square miles by its peak in Octobe-r-that's over three times greater than any other bloom on record. They then examined the conditions surrounding the bloom in order to find out exactly why it was so massive.

In the fall of 2010, conditions were ideal for harvesting and preparing fields; this meant that there was an increased application of fertilizers. In addition, the spring of the next year saw a series of strong storms; May rainfall alone was more than 75 percent above the prior 20-year average for that month. This caused the nutrients to be swept into the lake. In addition, the lake was beset by warmer water and weaker currents after the beginning of the bloom, which only exacerbated the conditions.

The researchers weren't done yet, though. They also determined the likelihood of future mega-blooms by analyzing climate model simulations under both past and future climate conditions. Unfortunately, their findings weren't comforting. Severe storms will only become more likely in the future, and calm conditions in the lake are likely to continue due to decreasing wind speeds across the U.S.

"Although future strong storms may be part of the new normal, better management practices could be implemented to provide some relief to the problem," said Anna Michalak, who led the Carnegie research team, in a press release.

The study reveals that if something isn't done, these conditions are only likely to worsen in the future.

The findings are published online in the Proceedings of the National Academy of Sciences.