Cyanos Activity September 27, 2022

 

Do not expose yourself or your pets to the water.

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 Tuesday, September 27th, AER visited Bantam Lake to conduct biweekly cyanobac-teria monitoring as part of the ongoing lake management program. Water column pro-file data, total depth measurements, and Secchi transparency data were collected from the North Bay Site (N 41.71087° W -73.21155°), the Center Lake Site (N 41.70056° W -73.22102°), 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).

Water samples were collected at the North Bay Site and Center Lake Site for algal analyses. These samples included whole water samples, which were integration of the top three meters of the water column, and a plankton net tow sample. These were pre-pared and analyzed as described in our April 15, 2022 memo.

Surface scums and cyanobacteria streaks were observed across much of the lake sur-face (Fig. 1). A sample of the surface scum was also collected and analyzed.

General Conditions

Air temperatures increased from the low to mid-50s °F during the our time on the lake

(https://www.wunderground.com/dashboard/pws/KCTLITCH9/graph/2022-09-

27/2022-09-27/daily). Dead calm conditions were encountered at arrival but picked

up by 9:30am.

Cyanobacteria and Algae Community

A total of 31 algae genera were observed in the plankton net sample, whole water samples,

and/or surface scum sample collected on September 27th. The taxonomic group

with the greatest richness (most individual genera) in the plankton next sample was

the Chlorophyta (aka green algae) with 12 genera identified, followed by the Cyanophyta

(aka cyanobacteria or blue-green algae) and Bacillariophyta (aka diatoms) which

had a total of seven and five genera identified, respectively. Four other taxonomic

groups were represented by three or fewer genera. The surface scum sample was

dominated by cyanobacteria.

Cyanobacteria genera counted or observed in the integrated and net tow samples included

Aphanizomenon spp., Aphanocapsa spp., Dolichospermum spp., Coelosphaerium

spp., and Microcystis spp., Planktothrix spp., and Woronichinia spp. The surface

scum sample was predominantly Dolichospermum spp. and Woronichinia spp.

(Fig. 2).