Keep your pets and family safe from toxic algae blooms

Toxic Algae Blooms Are Complex

Cyanobacteria are classified as a type of algae, and are responsible for many of the toxic algae blooms currently occurring around the globe. Cyanobacteria or Blue Green Algae are some of the most ancient organisms on the planet, which means they are good at surviving and even thriving in a changing environment. As our lakes, rivers and oceans become more polluted with nutrients like nitrogen and phosphorous some algae, because they are better adapted for those conditions will become more dominant over other species who are better adapted to unpolluted conditions. Add to this warming surface waters and you have rapidly changing environmental conditions that toxic cyanobacteria happen to love.

Given the ideal conditions (high nutrients and temperature) toxic cyanobacteria bloom, or grow exponentially until eventually the population crashes and everyone (almost) dies. When the billions and billions of algae cells die they began to break down, causing two bad things to happen: 1) as the dead cells are broken down in the water oxygen becomes depleted (the things that eat dead algae consume the oxygen) and 2) toxins held within the cyanobacteria are released all at once. Both of these things are bad for animals living in and drinking this water.

Toxic algae blooms can be deadly to people and animals by ingesting either the algae cells, or water that has high concentrations of toxins. In addition to making a person or animal acutely sick, algae toxins can have long term affects such as liver and nerve damage.

Being Safe Around Toxic Algae Blooms

If you live in an area that has experienced toxic algae blooms you should exercise extreme caution when coming in contact with natural bodies of water. Even if the algae bloom is gone and no longer visible it is possible to have toxins present in the water that can cause harm to people and animals. Follow the list of suggestions below to keep you, your family and pets safe.

  1. Do not enter waters that are visibly green.

  2. Check with managing agency to determine if the water body has had a recent toxic algae bloom.

  3. Keep pets on leash and do not allow them to drink or swim in contaminated water.

  4. If your municipal water supply comes from a lake that experiences algae blooms, drink filtered water.

Toxic Algae Monitoring and Management

Often toxic algae blooms occur in public waters, however they can occur in private lakes and ponds. It is important to monitor any water that people or animals will come in contact with to determine if toxic algae are present. Unfortunately alerts about toxic algae often come too late, after the bloom is already underway or dying. It is best to know as much about the bloom as possible as to be able to predict its impact in advance to avoid any illnesses or death. Knowing the location and abundance of the bloom can help us to make decisions about recreational and industrial usage of our surface waters.

We offer water testing to determine if you are having a toxic algae bloom. Just send us a water sample and we will identify what it is and make recommendations to you.

Algae Blooms: A general discussion

Algae blooms threaten public and environmental health. Certainly, better understanding of blooms is a first step towards helping to prevent them. Here is a general description of algal blooms for those interested in the topic. 

Here is an algal bloom in China. These non-toxic algae are still alive and growing, but when they begin to rot, the swimming hole will lose its appeal. 

Here is an algal bloom in China. These non-toxic algae are still alive and growing, but when they begin to rot, the swimming hole will lose its appeal. 


Algae are often quick to respond to changes in the environmental in order to take advantage of favorable conditions. Each algae species responds to environmental variables in different ways. For example, one species of algae may grow very quickly in hot temperatures while the same temperature would kill another species. Now think of all of the environmental variables working together to create the suite of conditions that an algae species lives in. It is a complex interaction of conditions that creates the current state of being, for the algae.


Another way to think of this is that when some condition is not favorable for a species, that condition is limiting the potential growth of an algae poplulation. In a population of alga the response to growth can be almost immediate, meaning that they can begin to divide, one cell into two to produce the next generation at a moments notice. Under very good conditions (less limiting variables) some algae may do this a few time per day, which can result in bloom conditions, leading to masses of algae in the water.


Algae blooms and their increasing frequency are likely due to the use of synthetic fertilizers in commercial agriculture, namely phosphates. Fertilizers are applied to increase the productivity of the target crops (corn, soy..), all of which is not used by those plants. The excess fertilizers are washed from the fields by rainwater and into waterways, surface water impoundments, lakes and coastal habitats. Algae, like plants, enjoy this fertilizer, and given that other conditions are favorable, like temperature, grow as fast as possible to take advantage of these wonderful resources. 


Algal blooms negatively affect drinking water supplies, water recreation, fisheries and the other organisms living in the area. Some of the algae that bloom produce toxins which can harm humans, pets, livestock and wild animals. The toxins released by that algae can contaminate shellfish and other seafood, making huge economic impacts in affected areas. Besides the toxins, the biomass left behind by the dying bloom begins to decay, creating dead zones in the water where oxygen is depleted (eutrophication) by the decomposition process. 


Here a bloom a kelp has washed ashore on Block Island, RI. 

Here a bloom a kelp has washed ashore on Block Island, RI. 

In recent years, scientists and regulatory agencies have become more interested in dealing with the problem of algal blooms. The EPA is considering adding algal toxins to its list of water contaminants monitored by the Clean Water Act. Besides being and interesting scientific topic, algae blooms are important for public and environmental health. Targeting and mitigating the causes of algal blooms is complex, but increasing understand should help to speed up the process. Educating ourselves and students about this topic provides a great opportunity for learning. 

Topics that could be covered related to algal blooms include:

  • Agriculture
  • Water Quality
  • Ecology
  • Biology
  • Public Policy
  • GIS
  • Statistics
  • Math
  • Use of Technology
  • Algal Identification