Cyanos Activity August 26, 2019
Water is clean for recreation.
Disclaimer: The information presented below reflects conditions throughout the lake and may differ from conditions on specific shorelines. For information regarding beach closings please contact the Torrington Area Health District or local town officials.
On August 26th AER visited Bantam Lake to perform biweekly cyanobacteria monitoring as part of the ongoing lake management program. Samples collected for algal identifications and enumerations were from the North Bay site (N 41.71087° W -73.21155°) and Center Lake site (N 41.70056° W -73.22102°). A plankton net tow sample, using a 10µm mesh plankton net, was also collected at the Center Lake site. Samples were treated, stored, and analyzed following methods discussed in a previous memo.
Water column profile and Secchi transparency data were also collected at the North Bay Site, the Center Lake Site, as well as at a site west of Folly Point (N 41.70773 W -73.22638), and at a site in the South Bay region of the lake (N 41.69015 W -73.22728).
Lake averaged Secchi transparency on August 26th was 1.91m and approximately 1m less than the August 12th average. Secchi transparencies ranged from a high of 2.23m at the North Bay site to a low of 1.65m at the Center Lake site (Table 1).
Concurrent with a decrease in Secchi disk transparency was a modest increase in cyanobacteria concentrations. However, concentrations at both sites were under 5,000 cells/mL and within the range of Visual Rank Category 1 at which no intervention is recommended.
Dolichospermum spp. and Aphanizomenon spp. were the dominant cyanobacteria genera observed. Both can fix nitrogen, regulate buoyancy, and synthesize a variety of cyanotoxins.
Water temperatures continued to slowly decrease with surface temperatures on August 26th ranging from 23.2°C at the South Bay site to 24.0°C at the Center Lake site. Temperatures at the bottom of the water column were similar to those measured at the surface with the exception of the Center Lake site. This site was the only one of the four that was still stratified and had anoxic conditions within the bottom 1m of the water column (Table 1). The thermocline at Center Lake was located between 6 and 7 meters of depth.
Literature Cited
Connecticut Department of Public Health and Connecticut Department of Energy andEnvironmental Protection. 2019. Guidance to Local Health Departments For Blue–Green Algae Blooms in Recreational Freshwaters.
Data is collected and analyzed by Aquatic Ecosystem Research, who is contracted by Bantam Lake Protective Association.
On August 26th AER visited Bantam Lake to perform biweekly cyanobacteria monitoring as part of the ongoing lake management program. Samples collected for algal identifications and enumerations were from the North Bay site (N 41.71087° W -73.21155°) and Center Lake site (N 41.70056° W -73.22102°). A plankton net tow sample, using a 10µm mesh plankton net, was also collected at the Center Lake site. Samples were treated, stored, and analyzed following methods discussed in a previous memo.
Water column profile and Secchi transparency data were also collected at the North Bay Site, the Center Lake Site, as well as at a site west of Folly Point (N 41.70773 W -73.22638), and at a site in the South Bay region of the lake (N 41.69015 W -73.22728).
Lake averaged Secchi transparency on August 26th was 1.91m and approximately 1m less than the August 12th average. Secchi transparencies ranged from a high of 2.23m at the North Bay site to a low of 1.65m at the Center Lake site (Table 1).
Concurrent with a decrease in Secchi disk transparency was a modest increase in cyanobacteria concentrations. However, concentrations at both sites were under 5,000 cells/mL and within the range of Visual Rank Category 1 at which no intervention is recommended.
Dolichospermum spp. and Aphanizomenon spp. were the dominant cyanobacteria genera observed. Both can fix nitrogen, regulate buoyancy, and synthesize a variety of cyanotoxins.
Water temperatures continued to slowly decrease with surface temperatures on August 26th ranging from 23.2°C at the South Bay site to 24.0°C at the Center Lake site. Temperatures at the bottom of the water column were similar to those measured at the surface with the exception of the Center Lake site. This site was the only one of the four that was still stratified and had anoxic conditions within the bottom 1m of the water column (Table 1). The thermocline at Center Lake was located between 6 and 7 meters of depth.
Literature Cited
Connecticut Department of Public Health and Connecticut Department of Energy andEnvironmental Protection. 2019. Guidance to Local Health Departments For Blue–Green Algae Blooms in Recreational Freshwaters.
Data is collected and analyzed by Aquatic Ecosystem Research, who is contracted by Bantam Lake Protective Association.
