All About Algal Blooms

Algae are microscopic organisms that live on land, in fresh water, and in the ocean. Essential to healthy lakes, estuaries, and all aquatic systems, algae provide food and oxygen that all water organisms need to survive.

An algal bloom is an over-growth of algae in a water body. Blooms occur in both fresh and saltwater. The result is a water stain of bright green, red, or brown. In some cases, aglal blooms are invisible to the naked eye.

Blooms are common in Florida, especially in the warmer months. While not all blooms are harmful, some produce toxins that kill fish and wildlife, and could make people sick. Blooms can grow large enough to deplete oxygen and block light to organisms below the water’s surface. In addition to ecosystem damage, blooms are unsightly and often negatively impact recreation endeavors. This results in slowed or even halted economic growth for the affected regions.

Understanding the Issue

While blooms occur naturally, scientists say both the frequency and intensity of current harmful algal bloom (HAB) activity is a signal of bigger problems. A contributing factor to the increase is heightened levels of phosphorous and nitrogen in waterways. Often, these elements run off from land surrounding drainage basins. Major sources of this excess in nutrients include urban land use, agriculture, waterway sediment, and carbon emissions.  

UF/IFAS is working with researchers and extension resources to identify and address the sources of Florida’s harmful algal bloom problem.