Cyanobacteria Mitigation Program Application Event #3

Area of Interest (AOI)-Pamunkey, AOI-Beverly and AOI-Duckinhole

Application dates:  July 18-19, 2022

Post-application monitoring dates: July 21-22, 2022

Application Tracks - GPS tracks of application locations on July 18th, 2022

AOI-Pamunkey


Application Tracks - GPS tracks of application locations on July 18th, 2022

AOI-Beverly


Application Tracks - GPS tracks of application locations on July 19th, 2022

AOI-Duckinhole


Application Tracks - GPS tracks of application locations on July 19th, 2022

AOI-Beverly


Data Plots

LACA monitors the lake prior to, during, and after each application event.  LACA collects field parameters using a YSI ProDSS handheld instrument.  The primary field parameters monitored by LACA include water temperature, pH, specific conductivity, and dissolved oxygen.  We also collect water samples for analysis using LACA owned instruments.  These instruments provide data on the amount of chlorophyll (CHL) and phycocyanin (PC) in each sample.  Chlorophyll is a chemical pigment used by plants and cyanobacteria to produce energy through the process of photosynthesis.  Phycocyanin is a chemical pigment only found in cyanobacteria.  The instruments we use provide us data on the concentrations of each pigment in the samples we collect.  We use these data, along with the field parameters collected with our ProDSS handheld device, to give us indications of the concentrations of cyanobacteria in the water.  The images below provide the pH and dissolved oxygen (DO) field parameters data over a fie day period for each sampling site in AOI-Goldmine and AOI-Duckinhole.

Note that the images below are thumbnails - click on an image to bring it into the view and then click on it again to get to a full page image.  You can save a plot to your computer if you right-click on the image and select "Save Image As" .  

LACA continues to monitor each of the Areas of Interest on a weekly basis after the application event has been completed for cyanobacteria population growth and all of the data will be considered in our project report to be developed after the 2022 recreational season. 

Application Event #3 Observations and Insights

Please direct questions or comments on these observations and insights to kicktheHAB@lakeannavirginia.org.

AOI Details and Product Application Plan:  AOI-Pamunkey covers an area of approximately 200 acres.  AOI-Beverly covers an area of approximately 17 acres.  AOI-Duckinhole covers an area of approximately 42 acres. 

The original plan was to treat AOI-Pamunkey and AOI-Beverly on both application dates.  LACA project managers had two meetings with BlueGreen Water Technologies to discuss data and trends noted from monitoring to date and the plan for Day 2 (19 July) application was modified based on the data and analysis.  The modified plan called for a re-treatment in AOI-Duckinhole due to the data obtained through 18 July for that AOI.  In addition, LACA decided to not treat AOI-Pamunkey on 19 July based on the continued positive data trends in that AOI. 

We treated AOI-Pamunkey and AOI-Beverly with 2 pounds of Lake Guard Oxy per acre on 18 July.  Based on the modified plan, we treated AOI-Beverly with another 2 pounds of Lake Guard Oxy on 19 July and AOI-Duckinhole with 6 pounds per acre on 19 July. 

The product was dispersed each day using wind direction and speed and other environmental considerations to determine dispersal tracks.  Actual ground tracks of the application are shown on the images included in this web report.

Day 1 (July 18) Recap:  Day 1 dispersal operations took place under sunny skies with a slight to moderate breeze in both AOIs.  It rained on the evening of July 17-18 and there was mud and debris in the water at AOI-Beverly and in AOI-Pamunkey west of the route 522 bridge. 

Day 1 of Application Event #3 (AE3) was also Day 5 sampling for Application Event #2 (AE2).  LACA sampled all cyanobacteria stations on July 18th due to this cross-over between AE2 and AE3.

Day 2 (July 19) Recap:  LACA met with scientists and data analysts from BlueGreen Water Technologies on the afternoon of 18 July and the early morning of 19 July.  Based on these discussions and data review, LACA decided to re-treat AOI-Duckinhole on July 19th and not treat AOI-Pamunkey.  The plan for AOI-Beverly stayed on track.  The decision to not treat AOI-Pamunkey was based on continued positive response from the June treatment of AOI-Pamunkey (Application Event #1, or AE1).  The decision to re-treat AOI-Duckinhole was based on a slightly positive response in that AOI after AE2 and a desire to obtain data on response to a re-treatment.  LACA established several research questions for the pilot/demonstration/experiment and AOI-Pamunkey’s continued positive response from AE1 coupled with a moderate response in AOI-Duckinhole from AE2 provided us an opportunity to address a research question on how an AOI would respond to a re-treatment soon after an initial treatment. 

Day 2 dispersal operations took place under initially sunny skies in AOI-Duckinhole that turned to overcast by the time we moved to AOI-Beverly for application activities.  Winds were calm throughout the morning application activities.  There was still evidence of the July 17/18 evening storm in AOI-Pamunkey. 

LACA continued to monitor AOI-Pamunkey to gather additional data on response in that AOI.  A red scum-like substance was seen in the western areas of the portion of the AOI west of the route 522 bridge.  The red scum encircled LACA’s PMCE1 station and was primarily seen along the shorelines.  Based on experience of red scum sampling in Pamunkey Creek, LACA believes the source of the red scum to be a Euglena species of algae.  One of the points raised by the BlueGreen Water Technologies Co-Founder and Chief Science Officer during our conversation on 18 July was that the “vacuum” created by the reduction of the cyanobacteria population would be filled by other species of phytoplankton in the water column as a “re-balance” of phytoplankton takes place.  This area of Upper Pamunkey Creek has a history of Euglena blooms so it is not that surprising that the Euglena species population increased.  However, an increase in the Euglena population is not the preferred response so LACA will research how this response can be avoided if a major mitigation program is initiated for the entire upper portion of the lake in 2023 and beyond.

Day 3 (July 20) Recap (sampling cancelled):  Day 3 sampling had to be cancelled due to a last-minute personal issue.  Due to the timing of the issue, there was no way to reschedule another boat captain to collect the samples and data.

Day 4 (July 21) Recap (sampling only – no application of Lake Guard Oxy product):  Day 4 sampling took place under sunny skies with a slight breeze throughout the morning sampling session.  The Euglena issue that had been observed in AOI-Pamunkey on July 19th was not observed.

Day 5 (July 22) Recap (sampling only – no application of Lake Guard Oxy product):  Day 5 sampling took place under sunny skies with calm winds throughout the morning sampling session.  Traces of the Lake Guard Oxy product were still visible in AOI-Duckinhole. The Euglena issue in AOI-Pamunkey returned with a mix of a green scum near the northern shorelines.  Based on the continued low readings of phycocyanin in the samples we collected coupled with elevated levels of chlorophyl LACA believes the green scum is caused by an algae species other than cyanobacteria.

Data Tabulation:

Field parameters for surface water (0.3m depth) for two stations in each AOI are provided in the tables below. 

Cells shaded in gray are pre-application values for each station (data from July 18th for AOI-Beverly, July 14th for AOI-Duckinhole, and June 16th for AOI-Pamunkey)

Parameter: Secchi Depth (m)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

0.35

0.35

0.30

0.30

0.40

0.25

Day 1 (18 July)

0.10

0.15

0.30

0.30

0.50

0.40

Day 2 (19 July)

0.35

0.20

0.40

0.40

0.45

0.40

Day 3 (20 July)

No sample

No sample

No sample

No sample

No sample

No sample

Day 4 (21 July)

0.40

0.35

0.50

0.40

0.40

0.40

Day 5 (22 July)

0.40

0.45

0.40

0.40

0.40

0.40


Parameter: pH (SU)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

9.26

8.99

7.02

7.11

8.54

7.69

Day 1
(18 July)

6.41

6.43

7.02

7.11

8.13

7.66

Day 2
(19 July)

7.68

6.64

8.51

7.21

8.42

8.53

Day 3
(20 July)

No sample

No sample

No sample

No sample

No sample

No sample

Day 4
(21 July)

8.52

8.47

8.25

8.86

8.67

7.34

Day 5
(22 July)

8.70

8.53

8.95

8.07

8.15

8.39


Parameter: DO (mg/L)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

10.92

10.67

6.31

6.64

9.29

8.77

Day 1
(18 July)

5.43

5.45

6.31

6.64

8.30

8.15

Day 2
(19 July)

9.18

5.22

8.99

7.35

8.44

9.12

Day 3
(20 July)

No sample

No sample

No sample

No sample

No sample

No sample

Day 4
(21 July)

9.60

10.28

8.09

9.53

8.99

7.14

Day 5
(22 July)

10.45

8.98

9.76

8.54

8.14

8.75


Parameter: DO (%)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

141.3

136.4

80.0

83.1

119.0

111.4

Day 1
(18 July)

63.2

63.3

80.0

83.1

108.2

104.9

Day 2
(19 July)

118.5

64.0

117.6

95.3

110.1

118.4

Day 3
(20 July)

No sample

No sample

No sample

No sample

No sample

No sample

Day 4
(21 July)

124.7

133.7

106.0

128.5

117.5

92.5

Day 5
(22 July)

135.8

116.7

131.5

113.6

104.8

112.7


Parameter: Phycocyanin [PC] (RFU)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

7,370.7

6,994.6

3,205.7

3,283.0

6,960.9

6,579.4

Day 1
(18 July)

280.1

240.2

3,205.7

3,283.0

6,540.1

4,753.9

Day 2
(19 July)

5,047.0

1,551.5

4,747.9

5,065.6

7,744.4

6,734.0

Day 3
(20 July)

0.000

0.000

0.000

0.000

0.000

0.000

Day 4
(21 July)

5,719.3

4,408.2

4,629.1

4,587.2

7,088.1

6,992.8

Day 5
(22 July)

4,906.7

4,476.7

5,114.8

3,884.0

6,524.5

6,852.5


PC Increase/Decrease from Pre-Application Value (%)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Day 1
(18 July)

-96.2%

-96.6%

0.0%

0.0%

-6.0%

-27.7%

Day 2
(19 July)

-31.5%

-77.8%

48.1%

54.3%

11.3%

2.3%

Day 3
(20 July)

N/A 

N/A

N/A

N/A

N/A

N/A

Day 4
(21 July)

-22.4%

-37.0%

44.4%

39.7%

1.8%

6.3%

Day 5
(22 July)

-33.4%

-36.0%

59.6%

18.3%

-6.3%

4.2%


Parameter: Chlorophyl [CHL] (RFU)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

16,601.7

16,578.7

7,689.0

7,227.4

14,279.7

13,661.0

Day 1
(18 July)

1,197.6

995.8

7,689.0

7,227.4

10,432.7

10,200.9

Day 2
(19 July)

15,444.0

9,683.9

10,526.1

12,932.3

12,921.7

12,870.3

Day 3
(20 July)

0.000

0.000

0.000

0.000

0.000

0.000

Day 4
(21 July)

11,935.0

15,608.0

14,340.7

9,678.9

12,607.7

14,331.3

Day 5
(22 July)

14,961.7

15,153.3

16,358.0

10,987.3

9,834.7

10,951.7


CHL Increase/Decrease from Pre-Application Value (%)

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Day 1
(18 July)

-92.8%

-94.0%

0.0%

0.0%

-26.9%

-25.3%

Day 2
(19 July)

-7.0%

-41.6%

36.9%

78.9%

-9.5%

-5.8%

Day 3
(20 July)

N/A 

N/A

N/A

N/A

N/A

N/A

Day 4
(21 July)

-28.1%

-5.9%

86.5%

33.9%

-11.7%

4.9%

Day 5
(22 July)

-9.9%

-8.6%

112.7%

52.0%

-31.1%

-19.8%


Parameter: Ratio of PC:CHL

AOI

Pamunkey

Pamunkey

Beverly

Beverly

Duckinhole

Duckinhole

Date

L38

PMCE1

B22

BEVE1

B20

DKCE1

Pre-Application Values

0.444

0.422

0.417

0.454

0.487

0.482

Day 1
(18 July)

0.234

0.241

0.417

0.454

0.627

0.466

Day 2
(19 July)

0.327

0.160

0.451

0.392

0.599

0.523

Day 3
(20 July)

N/A

N/A

N/A

N/A

N/A

N/A

Day 4
(21 July)

0.479

0.282

0.323

0.474

0.562

0.488

Day 5
(22 July)

0.328

0.295

0.313

0.354

0.663

0.626


Observations & Insights:

Field Data (pH and dissolved oxygen):

·         AOI-Pamunkey:  pH and dissolved oxygen levels in AOI-Pamunkey continued to remain below June’s pre-applications levels.

·         AOI-Beverly:  pH and dissolved oxygen levels increased in the AOI on the three sampling dates conducted after the application of Lake Guard Oxy.  This response is different than what has been observed in AOI-Pamunkey in the four weeks since the first application event in that AOI.

·         AOI-Duckinhole: pH and dissolved oxygen levels generally remained lower than pre-application levels on the 14th of July but the response is mixed in this AOI.

Lab Data (phycocyanin and chlorophyll):

·         AOI-Pamunkey:  Phycocyanin levels remained low through Day 5 with readings being 33.4% lower than June pre-application levels at station L38 and 36.0% lower at station PMCE1.  Chlorophyll levels also remained low through Day 5 with a readings of 9.9% lower than June pre-application levels at station L38 and 8.6% lower at station PMCE1.

·         AOI-Beverly:  Phycocyanin levels unexpectedly increased through Day 5 with readings being 59.6% higher than July 18th pre-application levels at station B22 and 18.3% higher at station BEVE1.  Chlorophyll levels also increased through Day 5 with readings being 112.7% higher than July 18th pre-application levels at station B22 and 52.0% higher at station BEVE1.

·         AOI-Duckinhole: Phycocyanin levels through Day 5 at station B20 were 6.3% lower than readings on July 14th but readings were 4.2% higher at station DKCE1.  Chlorophyll levels dropped at both stations with Day 5 readings at station B20 being 31.1% lower than on July 14th and 18.8% lower at station DKCE1.

AOI-Pamunkey continues to respond, in terms of both field and lab parameters, in a positive manner to the Lake Guard Oxy treatments in June and July.  This response provides LACA with valuable information on timing of treatments and dosage levels.

The response in AOI-Beverly was unexpected and contrary to what was observed in AOI-Pamunkey.  There could be several reasons for this unexpected response.  LACA will continue to sample water conditions in AOI-Beverly through the end of September and will analyze all data to determine possible reasons for the observed response.

The response in AOI-Duckinhole was mixed.  On Day 1, phycocyanin levels at both stations were lower than July 14th pre-application event #2 (AE2) levels but the decreases were not what had been observed in June for AOI-Pamunkey.  A decision was made to re-treat AOI-Duckinhole on AE3 Day 2 (19 July) with a dosage of 6 lbs./acre to measure its response to the re-treatment and higher dosage.  Phycocyanin levels prior to the re-treatment were 11.3 % higher than July 14th levels at station B20 and 2.3% higher at station DKCE1.  The measured response to the re-treatment on Day 4 (21 July) and Day 5 (July 22) was opposite of the expected results with the phycocyanin trend line rising to a 59.6% higher reading at station B20 and 18.3% higher reading at station DKCE1 by Day 5.  Field parameters during AE3 were also mixed with pH and dissolved oxygen readings showing instability across the five-day AE3 event. The response in AOI-Duckinhole will be analyzed closely to determine possible reasons behind the unexpected results.

There were no adverse environmental effects from the Lake Guard Oxy noted from July 14th through 18th.  

Next Steps

- LACA will continue to monitor phycocyanin and chlorophyll levels across the entire upper Lake Anna area. 

- LACA will continue to collect water samples and field parameters at all AOI stations.

- Lessons learned from Application Event #3 will be applied in the planned application events in August.


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