National Centers for Coastal Ocean Science-sponsored scientists have discovered that the common bloom-forming, freshwater harmful alga, Microcystis, produces estrogen-like substances that can alter sex hormones in fish, potentially causing feminization. The scientists from the University of Tennessee noted that human activities were previously thought to be the sole source for estrogen-like compounds in the environment.
Microcystis was already a concern because it produces liver toxins that can prevent recreational use of water bodies and may accumulate in drinking water. This new research enhances concern for both ecosystem and human health, because
Microcystis blooms have been increasing in freshwater and coastal areas due to increased nutrient inputs in some of the same areas where feminized fish have also been observed. This research is funded through the NCCOS Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) Program.