Cyanobacteria Testing Results
Cyanobacteria Levels
The values plotted are phycocyanin levels in micrograms/liter. Phycocyanin is a pigment specific to cyanobacteria so its levels reflect the levels of cyanobacteria. Grab samples were obtained at multiple sites (VMB: Veteran's Memorial Beach, S Cove: South Cove. World Health Organization alert levels for phycocyanin are: Level 1 (30 ug/L), monitor weekly to assess risk of a bloom. Level 2 (90 ug/L), limit recreation due to high potential risk of cyanotoxin.
2024
2023
Deep hole monitoring of cyanobacteria levels
Samples integrated over the top 10 feet of water in the deep hole were tested for levels of phycocyanin.
Microscopic Analysis of Deep Hole Cyanobacteria
- Plankton from the top 3 meters of water in the deep hole were concentrated with a plankton net. Bloom forming colonies were separated by flotation (ZAPPR), and counted using a Sedgewick Rafter counting chamber.
- Microcystis was the dominant genus in late July – Early August; Dolichospermum became the dominant genus in late August.
Background: Dolichospermum and Microcystis blooms often form during warm, calm weather in lakes and ponds with relatively high nutrient concentrations (nitrogen or phosphorus). Dolichospermum blooms usually contain other types of cyanobacteria, especially Microcystis, Woronichinia, Aphanizomenon, & Gloeotrichia. Tangled clumps of Dolichospermum may be colonized by stalked, filter-feeding zooplankton (See above: 2nd row, 2nd image from right).
