E. Coli and Cyanobacteria- More than Meets the Eye

SAGE SULARZ   Jul 26, 2023


 E. Coli and cyanobacteria are words every Vermonter has heard but what do they really mean and where do they come from? The Vermont government, with special mention to Burlington Parks and Recreation, does an amazing job testing and communicating water cleanliness with bi-weekly tests for E. Coli and daily inspection for cyanobacteria. Understanding the purpose of these tests and their implications are important to staying safe in the water. 

Escherichia Coli more commonly known as E. Coli, is a bacteria found in the digestive tract of warm-blooded animals, including humans. It is a large and diverse group of bacteria with different strains having different effects. As such, the E. Coli you think about regarding food borne illnesses is not the same strain that is being tested in the lake. The strain that is associated with water clarity is an indicator bacterium, the amount of sewage and waste in the water correlates with the levels of E. Coli. Adverse health effects are a result of the contaminates in the water not the bacteria itself. A very small percentage of this waste can be attributed to the overflow of human water treatment centers, runoff from nearby farms is a higher factor. In years with significant rainfall, more waste is transported and potential for illness is increased. 

Cyanobacteria are much more than just the bacteria that makes you sick in the lake; they are one of the largest and most impactful groups of bacteria in history. Cyanobacteria are unique in being the only single cell organism to perform photosynthesis and produce oxygen. They are the oldest discovered fossil dating back over 3.5 billion years and are largely credited with oxygenizing both the atmosphere and oceans of our planet. Today they are still beneficial in farming and an important part of aquatic ecosystems. However, harmful blooms can occur from rapid multiplication often in warm, slow-moving water. Additionally, waste runoff into the water provides a nutrient boost to the bacteria encouraging it to thrive. These blooms can block sunlight and monopolize nutrients causing harm to other aquatic life as well as producing powerful natural toxins. Blooms may or may not be identified visually and without a test it cannot be determined if toxins are present. Due to this it is safest to refer to official sources when deciding if a location is safe to swim and treat all blooms with respect as if they were toxic. 

This year the rain and heat has created an ideal environment for both E. Coli and cyanobacteria. For the most recent updates on testing and beach closures visit Burlington Parks and Rec website. In areas that have been identified as unsafe, diving is strongly discouraged. If you are experiencing symptoms after contact with contaminated water, contact your health care team. To learn more about the status of local dive sites, contact the Waterfront Diving Center and discuss safe options for fun dives or visit our website to browse our staff recommended shore dives. Getting away from the shore is another good option, charters leave from the shop 2-3 days a week; browse online or call the shop for scheduling and booking. 

To read more about the biology and epidemiology of these fascinating bacteria dive into the sources below! 

Cyanobacteria Blooms (CDC): 


Bacteria and E. Coli in Water (USGS): 


Cyanobacteria Evolution (Journal of Radical Biology and Medicine): 


Diarrheagenic Escherichia Coli (Clinical Microbiology Review):