Harmful Algal Blooms


What is a Harmful ALgal Bloom?

Harmful Algal Blooms, or HABs, occur algae starts growing out of control and produce toxins that can kill fish, mammals, and birds. These blooms can also cause illness and death in humans as well. Some algae that bloom are non toxic, but take up all of the oxygen in the water as they decay. This clogs the gills of fish and invertebrates, along with smothering coral and other aquatic vegetation, causing them to die.

What Causes HABs?

Three main things are needed in order for HABs to occur: sunlight, slow-moving water, and a high concentration of nutrients in the water (NOAA). While NOAA scientists know the factors that could contribute to HABs, it is not well understood how these things all come together to create HABs.

What Types of Organisms are Involved?

Algae is the only real organism involved in HABs, however, there are many environmental factors involved, such as climate for example. Human activities that disturb ecosystems also play a role in the more frequent occurrence and intensity of HABs. Increased nutrient loadings and pollution, food web alterations, introduced species, water flow modifications, and climate change are all factors in HAB occurrence (NOAA).

What are the ecological impacts, which species are impacted and how is the environment effected?

Ecological impacts: HABs negatively impact the food web by decreasing the amount of nutritious, edible phytoplankton that consumers need to survive. This decreasing in phytoplankton can lead to a food web collapse and eventually create a dead zone in the area.

Species impacted: All of the organisms that either feed on the phytoplankton or feed on the creatures that eat the phytoplankton will be effected by the HAB.

Environmental effect:

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

By controlling sewage, fertilizers, and industrial effluents there is a chance to reduce the chance of HABs forming in lakes and ponds everywhere. Some methods, such as Aeration, Hydraulic Manipulation, and Mechanical mixing, have been used in different area to control the nutrient levels in water.