Part I: Blue-Green Algae & Your Search Dog

In this 4-part series a few trusted experts will help us get clear on the facts surrounding the recent deaths caused by blue-green algae and what you need to know to safely respond to call-outs while keeping your dog safe. Today we welcome EPA Wetlands & Stream Scientist and FEMA Canine Search Specialist Eliodora Chamberlain to help us better understand what exactly is blue-green alga and where we should be keeping our eyes out for it.

What is blue-green algae?

Blue-green algae, more correctly known as cyanobacteria, are frequently found in freshwater systems. They are photosynthetic organisms that can feed off the sun to make their own energy and release oxygen. They are often confused with green algae, because both can produce dense mats that can impede activities like swimming and fishing, and may cause odor problems and oxygen depletion; however, unlike cyanobacteria, green algae are not generally thought to produce toxins.

Blue-green algae are a natural part of water-based ecosystems. They become a problem when nutrients (phosphorus and nitrogen) are present in concentrations above what would occur naturally. Harmful algal blooms (HABs) are overgrowths of algae in water. Some produce dangerous toxins in fresh or marine water, but even nontoxic blooms hurt the environment and local economies.

Some freshwater cyanobacterial blooms or cyanoHABs are able to produce highly potent toxins, known as cyanotoxins. Cyanotoxins are produced and contained within the cyanobacterial cells (intracellular). The release of these toxins in an algal bloom into the surrounding water occurs mostly during cell death and lysis (i.e., cell rupture) as opposed to continuous excretion from the cyanobacterial cells. However, some cyanobacteria species are capable of releasing toxins (extracellular) into the water without cell rupture or death.

Where is it found?

Harmful algal blooms are a major environmental problem in all 50 states in freshwater, estuaries and marine waters in the U.S. Red tides, blue-green algae, and cyanobacteria are examples of harmful algal blooms that can have severe impacts on human health, aquatic ecosystems, and the economy. HABs occur in waters (ponds, reservoirs, detention basins, lakes) that are nutrient-rich in nitrogen and phosphorous, exposed to a lot of sunlight, and/or in water that is slow-moving or stagnant.

When does it appear?

Certain environmental conditions in water bodies can intensify algae growth, causing algal blooms. HABs are caused by nutrient pollution, an excess of nitrogen and phosphorous, the use of fossil fuels, agriculture-manure, excess fertilizer, urban stormwater and wastewater/sewage treatment plants, industrial facilities that release nitrate compounds, and your own backyard from fertilizers, yard and pet waste, and certain soaps and detergents contain nitrogen and phosphorous if not properly used or disposed. Activities and uses such as these make the problem worse, which leads to more severe blooms that occur more frequently.

What does it look like (and what doesn't it look like)?

Harmful algal blooms can be green, blue, red or brown. The water may look foamy, scummy or look like paint on the surface of the water. You might also see dead animals floating in the water.

Here are examples of what it does look like:

Here are examples of what it doesn’t look like (Green algae):

How to tell if there is blue-green algae in the water?

A trained biologist can examine samples with a microscope to determine the exact type and number of organisms present, and some laboratories are equipped to test whether toxins from blue-green algae are present. However, anyone can perform a stick test or a jar test to determine whether a given algae sample is likely to be blue-green or another type.

For private water bodies, one can do a quick “stick” or “jar test” ( This is a self-assessment tool to see if a farm pond or lake may have blue-green algae present. It does not tell you which species are present. Remember that blue-green algae is naturally present in the environment, it only becomes hazardous when phosphorus and nitrogen are present in concentrations above what would occur naturally and they begin to produce toxins.

To definitively test if a water body has cyanotoxins/HABs, it is best to have it tested in a lab. This can be done through your state agency (environment or health) or local university. State departments of health or environment are the best sources for local information about harmful algal blooms. Click on this link ( to get more information on cyanoHABs in your state.

When in doubt, keep out!

Can I get my water tested?

To definitively test if a water body has cyanotoxins/HABs, it is best to have it tested in a lab.  This can be done through your state agency (environment or health) or local university.  State departments of health or environment are the best sources for local information about harmful algal blooms.  Click on this link ( to get more information on cyanoHABs in your state.

To report a suspected algal bloom in your state, click on this link ( to get more information.

Any words of advice for your fellow canine handlers?

HABs grow best in sunlight, nitrogen/phophorous rich, and slow-moving water.  So the safest thing you can do for you and your dog is to keep your dog out of any stagnant or slow-moving water body, especially if it smells bad.  If there are algal mats floating in the water, keep your dog out.  This can be hard to do when the temperatures are stifling, and your dog is hot.  I highly recommend proofing your dog off of water.  I know this sounds silly and possibly difficult, especially if you have a dog that loves water, but it could save their life.  All of my Labs LOVE water, and one of the first things I teach my dogs is that they are only allowed to get or go in the water under my command.  I’m not saying that they are perfect at leaving water (well, because they’re dogs!), but I do my best.  And I highly recommend that under hot or extremely hot conditions to be proactive about the heat status of your dog.  The best way to keep them out of the water (or listen to you with that “leave it” command) is to make sure that they don’t get to that point of overheating, and all they see and want is to get in the water.

A handler can also be proactive and do some research ahead of time.  When I have done searches in areas that are not known to me, I do my research on the area, and look up nearby water bodies.  I will go to that state’s environmental/health agency website and find a listing for contaminated waters and/or algal bloom water bodies (ex/  This can be found under a state agency’s website or possibly in their Clean Water Act 303 webpage (impaired waters list), or under their recreational water listings.

There are also mapping resources online that can tell you if a water body is impaired, and what it is impaired by.  One such resource is; click on the map link (insert to the right) to launch the application.  This will allow you to put in an address, lat/long or other geographic information of your area (or search area).  To the left you will find a column for “Layers”.  Under “Feature Layers”, you will find EPA data that contains listings and information for 303 Impaired Waters data, waters that are monitored, advisories, etc.  If you click on “303(d) Listed Impaired Waters”, and click on the red highlighted impaired water on the map itself, a box will pop up that will give you information, and provide more links that will  give you a ton of information along with the “Watershed Report”.

The more you know about the site you are going to search, the better you are able to safeguard you and your dog.

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