Harmful Algae Blooms (HABs)

Science Center Objects

Cyanobacterial harmful algal blooms (HABs) are increasingly a global concern because HABs pose a threat to human and aquatic ecosystem health and cause economic damages. Toxins produced by some species of cyanobacteria (called cyanotoxins) can cause acute and chronic illnesses in humans and pets. Aquatic ecosystem health also is affected by cyanotox­ins, as well as low dissolved oxygen concentrations and changes in aquatic food webs caused by an over-abundance of cyanobac­teria. Economic damages related to HABs include loss of recreational revenue, decreased property values, and increased drinking-water treatment costs.

Glass full of harmful algae (HAB sample)

Harmful algae sample

Harmful algal blooms (HABs) have been confirmed in inland reservoirs and lakes in Ohio, Kentucky, and Indiana, in the Ohio River, and in Lake Erie. Our research focuses on identifying the potential environmental factors that may drive HAB formation, documenting the effects of changing environmental conditions on HAB occurrence, determining the presence of naturally-occurring microcystin-degrading bacteria, and developing models to estimate toxin concentrations in recreational and drinking-water source waters.

Harmful algae bloom on Ohio River 2015

A 2015 cyanobacterial bloom on the Ohio River extended more than 650 miles and affected drinking water supplies and recreational activities in five States. (From Graham and others, 201 6). Photograph courtesy of the U.S. Army Corps of Engineers.

HABs are affected by a complex set of physical, chemical, biological, hydrological, and meteorological conditions, including excessive nutrients, primarily phosphorus and nitrogen. The most frequently proposed hypothesis relating to increased HABs in freshwater is an increase in nutrients from anthropogenic nutrient enrichment (human activities introduce excessive nutrients into a body of water).

An Algal Bloom may be called harmful because of resulting reductions in dissolved oxygen concentrations, alterations in aquatic food webs, unsightly scums along shorelines, production of taste-and-odor compounds that cause unpalatable drinking water and fish flesh, or the production of toxins potent enough to poison aquatic and terrestrial organisms. Many different types of algae can cause harmful algal blooms in freshwater ecosystems. However, the most frequent and severe blooms typically are caused by cyanobacteria, the only freshwater “algae” with the potential for production of toxins potent enough to adversely affect human health (From Graham and others, 2016).

To better understand and predict cyanobacterial toxin production, the USGS Ohio Water Microbiology Laboratory (OWML) in Columbus, Ohio, developed the capability to analyze samples by several molecular assays.




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