Cyanobacteria Around Bear Island

[ApS]

Originally Posted by Bear Islander

All summer I have had neighbors telling me there is cyanobacteria around Bear Island. One neighbor told me she witnessed cyanobacteria around my dock.

I keep going to the NHDES website on cyanobacteria and find no notices for Winni at all.

I just looked for the DES message about Winni mentioned in the last post. I can't find it.

The seems to be a disconnect here. Am I looking in the wrong place? Are we talking about different kinds of cyanobacteria?

Your neighbor may be referring to the precursor to cyanobacteria "poisonous blue-green algae blooms", which are the gloeotrichia. Those are the tiny gray dots that come within easy view of the surface on warm and windless days In late summer.

As a sailor, I have many hours on Lake Winnipesaukee on warm, windless, days in late summer. I can tell you gloeotrichia are easy to see and they're all over the lake.

At night, their natural buoyancy mechanism allows them to sink to deeper waters where they recharge their energy on Phosphorus.

Nobody's come right out and said it (yet) but all that Phosphorus has a common origin.
.
One Maine organization is collecting gloeotrichia data by means of a smart-phone app:

https://www.raymondmaine.org/content/gloeotrichia

[welch100]

The link to the DES page for the “sighting” is
https://www.des.nh.gov/news-and-medi...gloeotrichia-0

It is important to note that cyanobacteria is naturally occurring, and has always existed. Gloeotrichia is a Cyanobacteria. We have noticed it all over the lake for years, especially in the early fall. It looks like tiny greenish or yellow balls suspended in the water column, and it’s that suspension that distinguishes it from pollen that floats on the surface.

It becomes a problem, and a potential health risk, when it’s heavily concentrated in a “bloom.” This DES notice is merely a sighting of Gloeotrichia, not a notice of a dangerous bloom. There is no need for alarm; they are just advising caution if you see large concentrations of it. How do you know, practically speaking, what constitutes a large concentration? The only sure way is to call DES and ask them to come and get a sample for testing, but common sense dictates awareness and caution.

One more important Cyanobacteria fact - boiling water containing Cyanobacteria releases the toxins. Living on an island, lake water is pumped into our house. For many years, we used it for cooking pasta etc Out of caution, we don’t do that anymore.

Disclaimer - I am not an expert, just a person who has read up on this topic.😀

[rhubarbpie]

Originally Posted by ApS

Your neighbor may be referring to the precursor to cyanobacteria "poisonous blue-green algae blooms", which are the gloeotrichia. Those are the tiny gray dots that come within easy view of the surface on warm and windless days In late summer.

Just to be clear, gloeotrichia sighting is not a pre-cursor to a blue-green algae bloom. It is it’s own very special variety of Cyanobacteria which in very high concentrations forms a yellowish scum, but otherwise looks like tiny yellow/gray dots suspended at various levels under the water.

The Cyanobacteria spotted at Bear earlier this summer was not gloeotrichia, if I recall correctly, it was one of the more distinctly green varieties.

Sighting map here: https://www.winnipesaukee.org/weekly...oom-watch-map/

Images of Cyanobacteria here: https://www.winnipesaukee.org/wp-con...ance_FINAL.pdf

[Lake Winnipesaukee Alliance]

Originally Posted by ApS

Your neighbor may be referring to the precursor to cyanobacteria "poisonous blue-green algae blooms", which are the gloeotrichia. Those are the tiny gray dots that come within easy view of the surface on warm and windless days In late summer.

As a sailor, I have many hours on Lake Winnipesaukee on warm, windless, days in late summer. I can tell you gloeotrichia are easy to see and they're all over the lake.

At night, their natural buoyancy mechanism allows them to sink to deeper waters where they recharge their energy on Phosphorus.

Nobody's come right out and said it (yet) but all that Phosphorus has a common origin.
.
One Maine organization is collecting gloeotrichia data by means of a smart-phone app:

https://www.raymondmaine.org/content/gloeotrichia

Hi APS,

Great information! The cyanobacteria Gloeotrichia tend to not form blooms, but they do congregate in coves and on shorelines through wind/wave action. Other cyanobacteria types found on Winni, such as Dolichispermum, can form those surface scums that you are referring to. Nutrients most definitely have a part to play in "feeding" these blooms! LWA was recently featured in a Laconia Daily Sun article where we state "Too much phosphorus entering our lake promotes the growth of algae and aquatic vegetation, just like it helps the growth of grass and gardens."

[ApS]

While rebuilding our piling dock yesterday from formerly-unseen ice damage, I had ample time to check for gloeotrichia. On one occasion, a large and extremely dense concentration drifted by, illuminated by bright sun. (Which brought out their yellow coloration). This colony's movement was driven by our usual eastward "current", the weak breeze, and constant--but moderate in intensity--boat wakes. (These wakes generally favor eastward motion of "our" gloeotrichia).

About twenty minutes later, when I looked again, none could be seen. (Then with the sun blocked by deep shade from shoreline trees).

Originally Posted by Lake Winnipesaukee Assoc

Hi APS,
Great information! The cyanobacteria Gloeotrichia tend to not form blooms, but they do congregate in coves and on shorelines through wind/wave action. Other cyanobacteria types found on Winni, such as Dolichispermum, can form those surface scums that you are referring to. Nutrients most definitely have a part to play in "feeding" these blooms! LWA was recently featured in a Laconia Daily Sun article where we state "Too much phosphorus entering our lake promotes the growth of algae and aquatic vegetation, just like it helps the growth of grass and gardens."

For the record, I haven't referred to natural scum of any kind.

Winter Harbor has its deepest spot just east of Johnson's Cove: Benthic algae is measured there. A small brook feeds into Johnson's Cove, which is fed by 100 acres of open grasslands growing on poor soil, which is mostly clay. Those 100 acres are irrigated daily by lake water sourced from (our now) Phosphorus-rich lakewater.