Quote:
Originally Posted by tis
It is good. It eats the leaves and debris in the lake. I love watching it eat the patches and see the sand appear where the debris was.
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Those algae clouds are supported by runoff from shore and, using photosynthesis, "just grows". It is wave action that is clearing the leaves, the debris
and the algae. As long as there is sunlight filtering in, algae clouds appear in somewhat deeper water where there is no debris—fifteen-twenty feet? Maybe member
Diver1111 can advise.
If my neighbor's boys come up for the holiday weekend, I'll ask for pictures.
Those youngsters are reassuringly interested in lakes' fauna and flora.
Quote:
Originally Posted by tis
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Relax.
That picture is a concentration of the Blue-Green
Gloeotrichia—maybe collected from a fine-mesh fish net.
It's visible, and everywhere in the lake (down to about three feet), although not
that concentrated!
Wikipedia... :
Quote:
Freshwater Cyanobacteria. In North America Gloeoitrichia appears unexpectedly in many remote oligotrophic lakes during late summer and fall. It is also reported from several remote and pristine lakes in the undisturbed boreal forest watershed.Recently Gloeoitrichia was also found in 26 of 27 ‘low nutrient’ lakes in New England USA (Carey et al. 2012).
Likely the colonies develop in the bottom waters where sediment mineralization releases a portion of its phosphate, then adjust their buoyancy with displacement of bacterioplasm by elongating gas vesicles and rise to the surface where they can be distributed horizontally by wind-driven water currents. Blooms form in mid to late summer due to this ‘recruitment’ from the sediments, as the benthic colonies rise relatively in synchrony, measured in inverted funnel traps at up to 104 colonies m-2 day-1 in Lake Sunapee, NH USA (Carey et al. 2014).
Evidence that Gloeoitrichia is meroplanktonic, spending part or most of the year in sediments, comes from mesocosm growth experiments at Lake Erken. While open-water (pelagic) colonies were increasing during July 2000 – 2001, colonies in mesocosms (41 L and 300 L volume) were decreasing, even with additions of various combinations of nutrients (exception: addition of N, P and Fe) (Karlsson-Elfgren et al. 2005). The conclusion is that P-rich sediments enable colony growth and that increasing colony buoyancy during July brings them into the pelagic zone
Gloeoitrichia is also reported from some remote nutrient rich lakes surrounded by paddy field in West Bengal of India. Though this newly found paper which states about the presence of them in Bengal is not widely verified
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In other words,
Gloeotrichia rise as a cloud from the bottom of certain clear lakes, and spend some time at the surface. (That's what we're seeing). The presence of phosphorus (
P-rich sediments) is needed for growth, and supplied by shorefront erosion and runoff.
Tubers, skiers, wakeboarders, and especially wake-surfers are continuing to use Winter Harbor as usual.
Maybe spread the word?
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