2023 Cynobacteria Testing in Lake Garfield
Every two weeks starting in June, Shannon Poulin has been taking water samples from our lake. See her reports below.
Lake Garfield Final Water Quality and Cyanobacteria Report 2023
June 5, 2023
On June 5, 2023, two samples were taken one at the surface in the small bowl and the otherat 25 feet in the big bowl. The phycocyanin levels were at 0.10 parts per billion for both samples which is extremely low. The cell counts were 500 cells/mL of Microcystis. The cell counts at 25 feet was 300 cells/mL of Microcystis. The cell counts are nowhere near the state’s threshold of 70,000 cells/mL. At this time the lake is okay.
Compared to last year the results are the same as last year and that the cyanobacteria levels are low. The lake is 3 degrees colder than it was last year at the sampling time.
The temperature and dissolved oxygen (mg/l) were collected 1 to 25 feet. The oxygen was steady for the first 15 feet then dropped below 2 mg/l at 25 feet. The secchi depth was 8.6 feet meaning the water was pretty clear.
Figure 1. Estimated Lake Stratification
June 19, 2022
On June 19, 2023, one sample was taken on the surface of the small Bowl and one at 25 feet in the Big Bowl in 30.5 feet of water. The phycocyanin levels were at 0.10 parts per billion which is extremely low for both samples. The cell counts at the surface were 600 cells/mL of Microcystis. The cell counts at 25 feet were 440 cells/mL of Microcystis. Neither location had cell counts that are near the state’s threshold, therefore the lake is safe at this time.
Compared to previous years, Microcystis was the only cyanobacteria found this year whereas Dolichospermum and Aphanizomenon were also found. The lake is about the same temperature as last year.
The temperature and dissolved oxygen were taken at 1 to 25 feet. The oxygen levels were steady for the first 15 feet then decreased below 2 mg/L. The secchi disc had a reading of 10.2 feet.
Figure 1. Estimated Lake Stratification (where 0 is the surface of the lake).
July 10, 2023
On July 10, 2023, one sample was taken on the surface of the small Bowl and one at 25 feet in the Big Bowl in 30.7 feet of water. The phycocyanin levels were at 0.10 parts per billion which is extremely low for both samples. The cell counts at the surface were 900 cells/mL of Microcystis and 200 cells/mL of Dolichosperum. The cell counts at 25 feet were 750 cells/mL of Microcystis. Neither location had cell counts that are near the state’s threshold, therefore the lake is safe at this time.
Compared to previous years, the lake is consistent with low phycocyanin levels and cell counts. Compared to last year, Dolichosperum was present like the previous years while last year it was not.
The temperature and dissolved oxygen were taken at 1 to 25 feet. The oxygen levels were steady for the first 15 feet then decreased below 2 mg/L. The secchi disc had a reading of 8.5 feet.
Figure 1. Estimated Lake Stratification (where 0 is the surface of the lake).
July 31, 2023
On July 31, 2023, one sample was taken on the surface of the small Bowl and one at 25 feet in the Big Bowl in 30.1 feet of water. The phycocyanin levels were at 0.10 parts per billion which is extremely low for both samples. The cell counts at the surface were 1,000 cells/mL of Microcystis and 450 cells/mL of Dolichosperum. The cell counts at 25 feet were 500 cells/mL of Microcystis. Neither location had cell counts that are near the state’s threshold, therefore the lake is safe at this time.
Compared to previous years, the lake is consistent with low phycocyanin levels and cell counts. Compared to last year, Dolichosperum was present like the previous years while last year it was not.
The temperature and dissolved oxygen were taken at 1 to 28 feet. The oxygen levels were steady for the first 15 feet then decreased below 2 mg/L. The secchi disc had a reading of 7.8 feet.
Figure 1. Estimated Lake Stratification (where 0 is the surface of the lake).
August 11, 2023
On August 11, 2023, one sample was taken on the surface of the small Bowl and one at 25 feet in the Big Bowl in 30.5 feet of water. The phycocyanin levels were at 0.10 parts per billion which is extremely low for both samples. The cell counts at the surface were 2,000 cells/mL of Microcystis. The cell counts at 25 feet were 700 cells/mL of Microcystis. Neither location had cell counts that are near the state’s threshold, therefore the lake is safe at this time.
Compared to previous years, the lake is consistent with low phycocyanin levels and cell counts.
The temperature and dissolved oxygen were taken at 1 to 28 feet. The oxygen levels were steady for the first 15 feet then decreased below 2 mg/L at 25 feet. The secchi disc had a reading of 8 feet.
Figure 1. Estimated Lake Stratification (where 0 is the surface of the lake).
August 21, 2023
On August 21, 2023, one sample was taken on the surface of the small Bowl and one at 18 feet in the Big Bowl in 29.8 feet of water. The phycocyanin levels were at 0.10 parts per billion which is extremely low for both samples. The cell counts at the surface were 500 cells/mL of Microcystis and 100 cells/mL of Dolichosperum. The cell counts at 18 feet were 300 cells/mL of Microcystis. Neither location had cell counts that are near the state’s threshold, therefore the lake is safe at this time.
Compared to previous years, the lake is consistent with low phycocyanin levels and cell counts.
The temperature and dissolved oxygen were taken at 1 to 25 feet. The oxygen levels were steady for the first 15 feet then decreased below 2 mg/L at 25 feet. The secchi disc had a reading of 9.2 feet which has increased from the last sampling.
Figure 1. Estimated Lake Stratification (where 0 is the surface of the lake). The lake is turning over.
Taxa abrevation as follows:
Doli=dolichospermum
Micro=Microcystis
Apha=amphazamenon
Limn=Limnoraphis
Woro=woronichinia