Blue-green Algae Photo Gallery

You can't see individual cyanobacteria cells without a microscope. However, once enough cells collect into a colony these algae blooms become quite visible.

Blooms generally have the following properties:

There are a number of different types of blooms, and while not all produce toxins, you should watch for and avoid algae blooms.

To Report a Blue-green Algae Bloom

Blue-green Algae Blooms

Mallets Bay algae accumulation Mallets Bay algae accumulation






By mid-afternoon, the green color has been replaced by blue. This type of accumulation is easily mistaken for spilled paint or chemicals.

Left: Malletts Bay Fish and Wildlife access, Colchester VT, June 2006.  Blue-green algae (Anabaena species) are gathered among the shoreline vegetation in this mid-morning photo. The typical green coloration of algae is visible, as well as the blue that develops as the chlorophyll breaks down in stressed cells. 

blue-green algae blue-green algae

Left: Blue-green algae accumulating at the surface of the water near Highgate Springs VT, August 2007.
The very gentle wind formed the algae into these streaks and clumps.

blue-green algaeblue-green algae





Left: Shoreline accumulation of blue-green algae at the Rt 78 Fish and Wildlife Access on Missisquoi Bay. Note the distinct difference between the dense surface layer on the left and the mixed-up layer on the right. This abrupt change often occurs after a boat has passed through a thick accumulation and churned up the layer of algae.

Right: Blue-green algae at the northern end of Missisquoi Bay, August 2006. The lack of wind resulted in the algae gathering at the surface in clumps and swirls.

blue-green algae

blue-green algae

Right: Colchester Town Park, Colchester VT. Blue-green algae (Anabaena species) were noted along the shoreline in several areas of Malletts Bay. 

Left: Shelburne Pond Fish and Wildlife access, August 2006, Shelburne VT. Light winds pushed algae into this cove, resulting in a very dense green layer.

blue-green algae blue-green algae





Left: Blue-green algae accumulation at the Route 78 access in Mississquoi Bay during August 2006.

Right: Small shoreline accumulation of blue-green algae at Vantines Boat Launch, Grand Isle, in fall 2004. On this calm sunny day, water movement pushed the algae toward the shoreline, forming a layer and parallel streaks of color.

blue-green algaeAccumulation of blue-green algae near the mouth of the Pike River in Quebec, 2004.

Note the bright bluish green of the concentrated material near the shoreline and the more olive green of the less densely massed material offshore.


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NOT Blue-green algae

pollen on lake surface pollen on lake surface

Accumulation of pine pollen off Grand Isle, June 2005. Pollen can form clumps or layers, usually a mustard yellow in color. Older material may be darker and mixed with cottonwood seeds and other debris. This accumulation stretched for several hundred yards parallel to shore.

spirogyra algae

Floating mass of Spirogyra and Mougeotia (green algae) near Benson Vermont, June 2005. Green algae can be various shades of green. Floating mats like these are usually stringy. Other plant debris is often entangled in these mats.

ulothrix algae

Floating clumps of Ulothrix (green algae) near Grand Isle Vermont, May 2005. This algae grows attached to shoreline rocks and debris in the spring while the water is colder. Once the water temperature rises, they begin to die and break off the rocks. Accumulations of this material can form near shore or further offshore when carried by currents and wind. They will be a mix of brown and green from dead and dying plant material.

spirogyra algae

Submerged Spirogyra (green algae) at Carry Bay, May 2005. Cloudy masses of this algae are common among rooted plants around the lake all summer.

spirogyra algae

Shoreline accumulations of Spirogyra (green algae) at Converse Bay, June 2005. This algae is common along the lake shore in summer. Waves can break it off the rocks and disperse it. It can also dry on the rocks as water levels drop, leaving a brownish stringy coating.

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