Red Tide

Harmful Algal Bloom

By James Wilson & Zach Thibeault

What is a harmful Algal Bloom and what causes it?

A harmful algal bloom is an algal bloom that causes negative impacts to other organisms through production of natural toxic materials and/or damage to other organisms. these occur and are caused when a larger amount of algae and plants that live in the sea and freshwater grow at an uncontrollable rate that is becoming harmful to people, fish, shellfish, marine mammals, and birds. Slow water movement as well as overfeeding have been believed to lead to the overgrowing of algae. Also harmful algal blooms are common after extreme weather such as hurricanes, floods and drought.

what are the ecological impacts?

HABs can produce many dangerous toxins that can hurt and kill not only animals in the water but also people. Bigger animals in the ocean can swim away when the blooms start but slow animals and cessations get stuck in the bloom because of how fast they swim. They can also create dead zones in the water. On the other hand, it doesn’t only hurt the organisms in the water but also people on the land and industries that depend on clean water. This can raise the treatment cost for drinking water because all the nutrients ruining it.

Geographic Locations

For example, Red tides occur in the United States in Florida and the Gulf of Mexico. The organism(s) that create those red tides in Florida are exclusively in Mexico stretching from the gulf to Florida.

What type(s) of organisms are involved?

Organisms such as people, fish, shellfish, marine mammals, and birds are affected by harmful algal blooms. Marine animals are affected because it is part of their environment and the toxins will make them sick or even kill them. People get affected by the blooms because the toxins get on the food we eat from the sea. Besides getting sick, these toxins can lead to breathing problems and sometimes cause asthma attacks.

What can be done to reduce, eliminate or manage excess nutrients and solve this issue?

To help eliminate excess nutrients and solve the nationwide issue of HABs, you can volunteer to monitor water bodies with organizations such as the National Oceanic and Atmospheric Administration Phytoplankton Monitoring Network and the Association of Public Health Laboratories. Workers for these groups are asked to test local water twice a month and identify any Phytoplankton that it found. At home you can use phosphate free cleaning supplies, always pick up your pet’s waste and use safe fertilizer on your lawn. You can also report any suspected algal blooms you see to your state to help eliminate the problem before it gets any worse.


What are the economic impacts?

HABs have a big impact on many parts of the economy. Every year they cause about $82 million in total economic losses in industries such as seafood, tourism and fishing. They also have the ability to close beaches and shellfish beds, leading to even more money lost.
Predicting Harmful Algal Blooms
Algal Blooms Hit Center Stage