Photo: Association to Preserve Cape Cod
Learn more about what cyanobacteria are, what threat they may pose to your health, and what the Town of Barnstable is doing to mitigate these threats.
Introduction
18,000 years ago, a giant glacier known as the Laurentide ice sheet created Cape Cod, and along with it, 890 freshwater ponds. You may spend your summers along the edges of one of these beautiful waterbodies; soaking up the sun, paddling, sailing, or swimming. These ponds and lakes are home to hundreds of species whose livelihoods are now being threatened because of human activity.
Some Cape Cod residents can relate to the experience of a walk down to your favorite pond or lake ending with disappointment when you reach the waters edge only to find a sign advising you or your pet not to come in contact with the water. This experience could have also been accompanied by the sight of the ugly green goop on the waters surface. This blue-green sludge is called a Cyanobacteria bloom, and it is threatening the future of Barnstable’s fresh waterbodies.
An Overview
Cyanobacteria, also known as “Blue-Green Algae” are microscopic bacteria that live in all types of waterbodies. They can be harmful to human and animal health when skin contact occurs, if ingested, or if water droplets are inhaled. Learn more about the threat that Cyanobacteria has on your health here.
A large growth of these bacteria results in algal blooms. These blooms can pollute the water and may even be toxic to animals and people. When a dramatic increase in a cyanobacteria population occurs, this is called a harmful algal bloom (HABs). This often results in the waterbody turning bright green or blue-green, and forms a surface scum or a discoloration of the water column.
Due to its bright green hue, you may feel comfortable thinking you could always tell if a bloom is occurring, but that is not the case. CyanoHABs may also form a mat on the bottom sediments, making it more difficult to observe. The surface scums or discolored waters can extend several inches below the water surface, or accumulate near shorelines and in coves as a result of onshore wind activity. They often look like pea soup or spilled, blue or green paint; however, the color can also vary.
CyanoHABs can cause dissolved oxygen swings that may result in plant and animal die-off, taste and odor issues, and can cause potential public health issues from the cyanotoxins they may release.
The Issue
Typically, cyanobacteria’s potential for overgrowth is kept in check by a balance of several different factors, one of which is nutrient availability. All animals and plants require nutrients to grow and thrive, but if an external force makes nutrients either scarce or overabundant, the balance is disrupted.
Here on Cape Cod, human activities – from fertilization to septic systems – have introduced an overabundance of nutrients into the environment, which leads to an ecologically unhealthy condition called eutrophication (the process by which a water body becomes enriched in dissolved nutrients such as phosphates and nitrogen).
The greater the nutrient availability, the more fuel for cyanobacteria (and other undesirable plant life) to grow and thrive. Global warming also plays a key role with warmer pond temperatures favoring cyanobacteria. Learn more about cyanobacteria monitoring across Cape Cod through Barnstable County’s efforts here.
Water Quality Testing
Photo: Association to Preserve Cape Cod
In order to keep the residents of Barnstable and Cape Cod safe, Barnstable County, partners with the Association to Preserve Cape Cod (APCC), a local non-profit environmental organization. Together they proactively monitor Cape Cod’s ponds and lakes for cyanobacteria, and, more specifically, the toxins they sometimes produce. You can view a county-wide map with current Cyanobacteria monitoring results here.
Ponds and lakes across Barnstable are regularly tested to make sure that Barnstable residents are safely enjoying their waterways. Should a Town waterbody fail to achieve an acceptable result during testing, advisories will be posted on our Cyanobateria Monitoring page via a Town of Barnstable Water Quality Report as well as shared on the MyBarnstable mobile app, via Town social media, and physically posted at the waterbody site.