Harmful Algal Blooms (HABs)

What are Habs?

Harmful algal blooms (HABs) occur when colonies of algae grow to problematic levels. HABs can produce toxic effects on people and wildlife, starve ocean and coastal ecosystems of oxygen, or stop sunlight from reaching seagrasses, which buffer coastal communities from storms.

HABs are a growing problem for every U.S. coastal and Great Lakes state, threatening drinking water sources, fisheries, marine ecosystems, public health, and coastal economies. A single major HAB event can cost the U.S. tens of millions of dollars.

These blooms can be caused by many factors, including nutrients and above-normal temperatures. The frequency and duration of HABs, along with the number of species responsible, have all increased in recent years. The geographic ranges of some harmful algae are also expanding.

IOOS IN ACTION

The National HAB Observing Network (NHABON), a joint effort between IOOS and the National Centers for Coastal Ocean Observing, connects federal, state, and local partners to improve understanding, detection, and management of HABs. NHABON works to address community needs related to HAB observing to safeguard ecosystems and natural resources. The network also advances innovative technologies and research to address this costly and dangerous threat.

IOOS Regional Associations develop projects to observe HAB species and toxins of relevance to their waters and communities. Species of algae, the toxins they produce, the impacts they have, and how they are detected all vary regionally. A sustained HAB observing network supports detection, early warning, and HAB forecasts to protect communities and ecosystems from a range of threats, including shellfish mortality events, drinking water quality issues, and hazardous seaweed blooms.

NHABON Webinars & Events

Learn more about upcoming community webinars and events on the NHABON page.

Our Partners in Action: IOOS Making a Difference

We use the Seagull platform regularly to understand how water quality from rivers influence Lake Erie. This information helps us better understand the formation and intensity of harmful algal blooms, which are a known threat to human health. IOOS regional data (GLOS) improves our ability to manage water resources in the Great Lakes to provide key services such as drinking water, fishing, and recreation.

Laura Johnson, Heidelberg University
IOOS regional data (SCCOOS) helps us forecast and report to our community about HABs—in particular surfers who are prone to bites by impacted sea lions, and others who experience rashes and sinus infections from HABs.
Joy Downing Riley, Surfrider Foundation
We utilize IOOS data to monitor HABs, which offer insights into cetacean mortality. In 2023, our region experienced a surge, with over 130 deceased cetaceans within weeks. IOOS played a pivotal role in pinpointing the areas impacted by this mortality event.
Lili Hartounian, Channel Islands Cetacean Research Unit

Having the NANOOS automated HAB sampler, with toxin assessment capability, offshore between our harvest beaches and the HAB generation sites will give Tribes the forewarning they need to adjust sampling protocols and better protect the health of coastal residents, tribal and non-tribal.

Joe Schumacker, Department of Fisheries, Quinault Indian Nation

Our regional IOOS association (SECOORA) funds critical work to perform high resolution water quality tracking alongside harmful algal bloom monitoring in coastal Georgia, one of few such operations in our state.

Natalie Cohen, University of Georgia