Harmful Algal Blooms
Satellite image of Lake Erie from 2004 showing a mild HAB in the southwestern portion of the lake. Image courtesy of ESA/MERIS; Processed by NOAA/NCCOS.
Algae that grow very fast can form dense populations or "blooms". A small percentage of blooms produce toxins or grow excessively, harming humans, other animals, and the environment. HAB toxins may kill fish or shellfish directly, and people who eat contaminated seafood may also become sick or suffer fatalities if they ingest sufficient toxins. Even blooms that are not toxic can cause damage by suffocating fish, blocking light from bottom-dwelling plants, or depleting the oxygen in the water.
HABs occurring in U.S. marine waters are conservatively estimated to have an average annual cost of $82 million due to impacts on public health, tourism, and the seafood industry. Every U.S. coastal state has suffered a bloom of harmful algae over the last decade, and new species have emerged in some locations that were not previously known to have problems.
HABs occur naturally, but human activities that disturb ecosystems seem to play a role in the increased occurrence of some blooms. Increased nutrient loadings and pollution, food web alterations, introduced species, water flow modifications, and
climate change have all been implicated.
NOAA is authorized by the Harmful Algal Bloom and Hypoxia Research and Control Act (HABHRCA 1998, 2004) to help communities counter this increasing threat through research in its labs and centers and to augment our expertise by funding research by our extramural partners.
NCCOS Harmful Algal Bloom research is focused on the following subjects and programs.