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Out-of-Season Algae Outbreaks on the Rise

In the News
Wednesday, April 3, 2019

Outbreaks of toxic algae in U.S. waterways usually happen in warmer months. But in a sign that the problem is growing worse, algae blooms were reported in December in Michigan and Washington state, with another reported in Florida during the first days of spring.

EWG’s ongoing tracking of reported algae outbreaks found a record 255 blooms in 2018, an increase of about 54 percent from 166 in 2017. We’re in the process of updating our map of news reports to show 527 algae outbreaks since 2010, in 463 different lakes, rivers, ponds, oceans and towns. 

Blue-green algae, which are actually microscopic organisms called cyanobacteria, appear when nitrogen and phosphorus from fertilizer and animal manure run off farm fields into water. In some cases they are merely ugly and smelly. But in others, they destroy aquatic ecosystems and pose a health risk to animals and human health.

Because rain and heat amplify the growth of these blooms, they are most common in the summer. But outbreaks have increasingly been popping up in the late fall and winter, when temperatures are at their lowest. Between last October and early April, there were 23 reports of blooms.

Given the overall uptick in outbreaks, it makes sense that blooms have increased in places that stay warm all year, such as California and Florida. Florida’s toxic red tide, which killed thousands of marine animals and sickened numerous beachgoers last summer, spread to Alabama’s coast in late November.

In December, cyanobacteria were detected in tests of residential drinking water in Adrian, Mich. Outbreaks were also found in two lakes in Washington state that same month. One of those lakes was located in a popular park, where visitors were warned to keep their pets away.

Algae outbreaks have significant negative economic and health consequences. But we’ll continue to see more unless industrial-scale animal farms adopt conservation practices to prevent farm runoff from getting into bodies of water.


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