Algal Bloom FAQ
+ What are algae?
Algae are microscopic organisms called plankton that naturally occur in all bodies of water, including lakes and oceans. They are single-celled organisms that are photosynthetic, meaning they use sunlight to make their food. In warm, nutrient-rich (high levels of nitrogen and phosphorous) waters, algae multiply quickly and can form algal blooms that cover the surface of the water and look like large mats.
+ How are algal blooms formed?
Algal blooms are formed when there are elevated levels of nitrogen and phosphorous, two nutrients that are necessary for algal growth, in slow-moving and warm waters. These elevated levels of nutrients can result from stormwater carrying fertilizer in runoff from farms, lawns, and golf courses and from sewage spills. Algae grows rapidly when there are elevated nutrients, leading to algal blooms. These blooms can occur year-round, but are often seen during the late summer and early fall, when water temperatures are warmer.
+ How can you identify an algal bloom?
The majority of algal blooms consist of algae that are buoyant, and may be sitting on top of the water, and look like a mat, scum or foam layer. However, not all algal blooms will appear on the surface of the water, as they can be found deeper in the water or on the bottom of the waterbody. Depending on the type of algae, the blooms will range in color from blue to green, brown or red, and may have an unpleasant odor, like rotting plants. There are several different types of algal blooms, and for further information on how to identify each type see this informative field guide on observing algal blooms.
+ Are algal blooms harmful to humans?
Algae are capable of producing many chemicals, including toxins that harm humans and animals. Algal blooms that may be a threat to humans are called “Harmful Algal Blooms” (HABs). However, not all algal blooms are harmful and you cannot tell whether they are harmful just by sight. HABs can impact humans both directly and indirectly. Indirectly, these blooms may become so large that they prevent sunlight from penetrating through the water, not allowing plants to photosynthesize and produce oxygen. With less oxygen in the water, massive fish die-offs will occur. Directly, some algal blooms may carry toxins, specifically called cyanotoxins, which can cause both people and animals to become sick. People or animals may become sick when the following occurs: 1) Participating in recreational activities (i.e. swimming) within a body of water with HABs 2) Breathing in tiny water droplets or mist containing the toxic water 3) Drinking contaminated water 4) Eating contaminated food (fish or shellfish)
+ What are the symptoms of sickness caused by harmful algal blooms (HABs)?
Symptoms may include skin, eye, nose or throat irritation, headache, vomiting and diarrhea. Pets may experience similar symptoms. If you or your pets seem to be experiencing these symptoms, please contact your doctor or veterinarian.
+ How can you test for algal blooms?
Several state agencies routinely test for algal blooms within Alabama’s waterways, including Alabama Department of Public Health’s Seafood Division, Alabama Department of Conservation and Natural Resources’ Marine Resources Division and the Dauphin Island Sea Lab. These agencies are responsible for testing the water quality and seafood to inform citizens of any HAB concerns. They are also responsible for closing and opening waterways to protect citizens. The HAB tests can be costly and difficult for citizens to conduct themselves, and there is currently no tool or app to report a HAB. If a citizen sees a potential HAB in a waterway, they should call the Alabama Department of Environmental Management’s Coastal Section (251-304-1176) or Water Division (334-271-7823) to report it.
+ How can I protect myself from HABs?
If you suspect a harmful algal bloom is in the water, follow these instructions:
- Don’t swim or participate in any other recreational activities in that body of water
- Do not let pets play or swim in the water, and do not let them drink the water
- Stay out of the water if there are dead fish in it
+ How do I avoid toxin-contaminated fish and shellfish?
Check with your local health and environmental officials before you fish or collect shellfish, and check state fish advisories concerning harmful algal blooms that may be posted at fishing supply stores, beach managers, or your local authorities. You can call 844-219-7475 to hear fish consumption advisories for different regions around the state of Alabama. Once a fish or shellfish has the toxin in its body, it cannot be removed. Harmful algal bloom toxins are not destroyed through cooking, freezing or salting.
+ How can you prevent algal blooms?
- Fertilizer run-off from residences is a major cause of harmful algal blooms. Do your part to research fertilizers before using them in your yards and gardens, and only use the recommended amounts to reduce the amount of runoff into the environment. Chat with your lawncare providers to make sure they are using environmentally-friendly fertilizers and are not using more than the recommended amounts.
- Sewage spills may also lead to harmful algal blooms in our local waterways. You can learn more about sewage spills here. If you see a sewage spill, please report it to Mobile Baykeeper and to your local authorities.
- Properly maintain your household sewage system to prevent wastewater from leaking out into the environment. Sewage can be filled with nutrients that are food for algae. A sewage system is made up of lines and mechanisms to transport your wastewater from your home to a wastewater treatment plant. The portion of the line that connects to your house is called the ‘lateral line’. If the lateral line is located near trees, the roots from the trees can create a crack in the line, resulting in blockages. An additional threat to lateral lines is stormwater. When stormwater infiltrates a line, it overflows the line and wastewater is then forced out of manholes, flowing into storm drains where it is then eventually washed out into local waterways. Keep stormwater out of the lateral line by replacing missing or broken cleanout caps, which cover your lateral line. If you are on a municipal city sewer, make sure the line that carries your sewage from your home to the system is intact and does not allow rainwater to enter the system.
Every day, Mobile Baykeeper works to respond to citizen concerns, whether they are algal blooms, sewage spills, stormwater runoff, or anything else. Please report your environmental concerns to us or to the appropriate authority.
We cannot do this work without continued support from our community. We are a member-based, member-driven organization with a focus on results. Please consider becoming a member today to support clean water for your family and your community.