Algae are natural and important to aquatic ecosystems (lakes, streams/rivers, estuaries, and the ocean). Under certain conditions, some species can produce toxins that affect human health and the environment. Algae can grow in excess (blooms), leading to harmful impacts on the environment such as low/no oxygen (hypoxia/anoxia) or acidification (reduced pH levels in the water). These blooms may affect individuals and communities through unsightly conditions, toxins, or taste and odor issues that affect recreation, tourism, and drinking water. Pets and livestock may also be affected.

Algal growth leading to impacts on human health and the environment are referred to as Harmful Algal Blooms (HABs). HABs can occur in all water types, and some can move with water flow. In Louisiana, HABs most often concern a group of algae called cyanobacteria or blue-green algae. These are present most often in fresh waters and in lower salinity estuarine waters. These HABs are also known as HCBs or CyanoHABs, and can be present across the state at varying times of the year. Other types of HABs (for example red tide) may occur in more marine waters from time to time.

CyanoHABS:

• Viewing
  •  Satellite imagery is the best way to determine location and extent of these blooms.  The USEPA has developed a web dashboard for larger waterbodies that allows users to view maps with estimated CyanoHAB density by area. 
    • Cyanobacteria Assessment Network Web App
      • App Information
        • Registration is required
        • Maps are often updated daily, but may vary by a couple of days
        • Cloudy conditions block views; the presence of CyanoHABs under clouds is unknown
        • Toxin production cannot be predicted by satellites
        • Satellite products are not perfect—they’re a useful tool in decision making about water-based activities in an area
  • Satellite imagery for the Lake Pontchartrain area has been developed by NOAA’s National Centers for Coastal Ocean Science.
    • https://coastalscience.noaa.gov/science-areas/habs/hab-monitoring-system/cyanobacteria-algal-bloom-from-satellite-in-lake-pontchartrain-la/
• Prediction
  • Using satellite imagery and other metrics, the USEPA has also developed a web dashboard that provides weekly CyanoHAB forecasts for decision making.
    • Freshwater Forecasts Web App (allow time to load)

Marine HABs

• Marine HABs occur within Louisiana’s coastal zone occur less frequently; currently there is no known visualization or forecast application/s for our state.

• U.S. Environmental Protection Agency (USEPA) Information on HABs
• US Environmental Protection Agency (USEPA) How People and Animals Are exposed to HABs
  • Dogs
• Centers for Disease Control Information on HABs

Public concerns regarding HABs in Louisiana may be sent to this address:  _DEQ-WWWWaterQuality@LA.GOV