Weekly Indian River Lagoon

Harmful Algal Bloom Observations

Project Summary

Report Date - January 9th to January 15th, 2023

Project Name: Florida Department of Environmental Protection Grant INVO14: Remote Sensing of Harmful Algal Blooms in the Indian River Lagoon and Connected Waterways in Brevard County


Prepared By: Andrew Kamerosky

Status Summary

Summary of Harmful Algal Bloom (HAB) Activity

For the week of January 9, 2023, to January 15, 2023, there was minor HAB activity continuing from the previous week primarily within the Banana River. There was new activity this week throughout the IRL except for the Central IRL. The low temperatures starting on January 13th did not appear to have an impact on HAB activity. There were 2 Sentinel-2 and 5 Sentinel-3 usable scenes during this period.


The estimated Chlorophyll A (ChlA) in the southern Mosquito Lagoon increased from a median of 13.26 µg/L on January 11th to 21.08 µg/L on January 15th. The North-North IRL increased from a median of 8.06 µg/L on January 11th to 17.42 µg/L on January 15th. The Central-North IRL increased from a median of 13.28 µg/L on January 11th to 20.43 µg/L on January 15th.


The estimated ChlA in the northern section of Banana River increased from a median of 27.61 µg/L on January 11th to 34.05 µg/L on January 15th. The middle section of Banana River also increased with a median of 35.05 µg/L on January 11th to 36.57 µg/L on January 15th. The southern section of the Banana River also increased with a median of 15.01 µg/L on January 11th to 20.14 µg/L on January 15th.


In the South-North IRL there was an increase with a median of 9.78 µg/L on January 11th to 12.83 µg/L on January 15th. The North-Central IRL was the only section to decrease, with a median of 20.99 µg/L on January 11th to 17.26 µg/L on January 15th.

Available Sentinel 2 & 3 Imagery

The availability and usability of satellite imagery is contingent upon both the satellite being overhead and low cloud cover. The orbits of the Sentinel satellites will on occasion cover a portion of the Indian River Lagoon. Likewise, cloud cover can also result in only portions of the Indian River Lagoon (IRL) being visible. Table 1 below lists the availability of Sentinel imagery and its usability for Harmful Algal Bloom (HAB) analysis.

Table 1 - Sentinel 2 and 3 imagery availability for January 9th-January 15th, 2023

Date

S2 - A

S2 - B

S3 - A

S3 - B

09-January-23

N

N

N

N

10-January-23

N

Y - P

N

Y - C

11-January-23

N

N

Y - G

Y - G

12-January-23

N

N

Y - G

N

13-January-23

N

Y - C

N

Y - C

14-January-23

N

N

N

Y - G

15-January-23

Y - P

N

Y - G

N

N - Imagery Not Available

Y - C - Imagery Available, Cannot Use Due to Cloud Cover

Y - P - Imagery Available, Only Partial Imagery of IRL

Y - G - Imagery Available, No Issues Over the IRL

Processed Imagery

10 January 2023 - Sentinel 2B

11 January 2023 - Sentinel 3A

12 January 2023 - Sentinel 3A

14 January 2023 - Sentinel 3B

15 January 2023 - Sentinel 2A

15 January 2023 - Sentinel 3A

SJRWMD IRL Continuous Monitoring Stations

The St. John River Water Management District (SJRWMD) Continuous Monitoring (CM) stations measured generally stable Chlorophyll Reflective Fluorescence Units (RFU) at all sites except for IRLI21 which had a peak and crash (Figure 1, Table 2). 


IRLI21 began the week with 8.02 RFU on January 9th, followed by an increase to 12.35 RFU by January 12th, and then a decrease to 7.51 RFU on January 15th. All other sites were below 6.5 RFU the entire week, with a decline in RFU following a period of low temperatures starting January 13th. IRLIRCMTITUS01 however was the only other site to have an increase after the decreased temperatures.


Current and historical data are added to the SJRWMD’s database continuously; subsequent visits may reflect such additions or revisions. SJRWMD provides no warranty as to the accuracy, reliability, or completeness of these data.

Figure 1 - St Johns River Water Management District (SJRWMD) Indian River Lagoon Continuous Monitoring Station Relative Chlorophyll A (ChlA) readings from January 9th-January 15th, 2023, as described in Table 2.

Table 2 - St Johns River Water Management District (SJRWMD) Indian River Lagoon Continuous Monitoring Station Relative Chlorophyll A (ChlA) Relative Fluorescence from January 9th-January 15th, 2023.

Date

IRLML02

IRLIRCMTITUS01

IRLB04

IRLI13

IRLI21

09-January-2023

6.43

5.57

2.82

3.63

8.02

10-January-2023

6.28

5.76

2.67

4.05

8.64

11-January-2023

5.53

5.67

2.69

4.86

11.84

12-January-2023

5.04

6.05

2.63

5.42

12.35

13-January-2023

5.45

6.07

3.55

4.47

8.29

14-January-2023

6.10

5.39

2.51

3.28

6.75

15-January-2023

3.54

5.91

2.63

3.07

7.51

European Space Agency Sentinel Satellite Estimated Chlorophyll A


Sentinel 2

Two partial scenes from Sentinel 2 were usable for detection of HAB activity from January 9th, 2023, to January 15th, 2023. The following analysis focused on the scenes from January 10th and January 15th. There were several small patches of cloud cover over the IRL on both days, which likely resulted in small areas of ChlA overestimation. 


These partial scenes did not have imagery from the Mosquito Lagoon or North IRL (NIRL).


The north section of the Banana River from State Road 528 to the NASA Parkway East causeway on January 10th had an estimated ChlA median of 33.06 µg/L, 3rd Quartile of 41.40 µg/L, and maximum of 173.99 µg/L. This was an increase from the previous estimated median of 27.65 µg/L on January 5th. On January 15th there was a median estimated ChlA of 40.63 µg/L, 3rd Quartile of 51.06 µg/L, and maximum of 189.22 µg/L.


The central section of the Banana River from Cocoa Beach to State Road 520 on January 10th had a median estimated ChlA of 37.87 µg/L, 3rd Quartile of 44.09 µg/L, and maximum of 121.62 µg/L. This was an increase from the estimated ChlA median of 27.37 µg/L observed on January 5th. By January 15th the estimated ChlA median increased to 42.73 µg/L, 3rd Quartile of 51.06 µg/L, and maximum of 152.83 µg/L. 


On January 10th the southern section of the Banana River between Cocoa Beach and Patrick Space Force Base there was a median estimated ChlA of 18.52 µg/L, 3rd Quartile of 30.36 µg/L, and maximum of 113.35 µg/L. This was an increase from the estimated ChlA median 13.89 on January 5th. By January 15th the estimated ChlA median increased to 26.05 µg/L, 3rd Quartile of 31.28 µg/L, and maximum of 178.67 µg/L.


The minor bloom in the Banana River appears to have generally withstood last week’s cold snap, however all three sections experienced small increases in estimated ChlA. This contrasts with the reduction observed following the previous cold snap. The south section of the Banan River also continued to have the lowest estimated ChlA of the Banana River. Further investigation is needed to determine why this location is less supportive of the current HAB taxa.

 

On January 10th in the South NIRL from State Roads 528 to 404 there was an estimated ChlA median of 17.79 µg/L, 3rd Quartile of 36.29 µg/L, and maximum of 152.39 µg/L. This was a decrease from the estimated ChlA median of 21.45 µg/L on January 5th. By January 15th the estimated ChlA had a median of 20.72 µg/L, 3rd Quartile of 27.88 µg/L, and maximum of 169.83 µg/L. 


On January 10th in the North Central IRL (CIRL) from State Road 404 to Turkey Creek there was an estimated ChlA median of 32.62 µg/L, 3rd Quartile of 43.93 µg/L, and maximum of 112.62 µg/L. This was an increase from the estimated ChlA median of 28.37 µg/L on January 5th. By January 15th the estimated ChlA had a median of 22.51 µg/L, 3rd Quartile of 28.11 µg/L, and maximum of 142.36 µg/L. 


Sentinel 3


Five scenes from Sentinel 3 were usable for detection of HAB activity from January 9th, 2023, to January 15th, 2023. The following analysis focused on the scenes from January 11th and January 15th (Table 3, Table 4).


Of the 5 SJRWMD CM stations, the highest mean estimated ChlA concentrations on January 11th were observed at IRLB04 and IRLI21 with almost 30 µg/L. Then on January 15th IRLB04 had the highest estimated ChlA at 38.41 µg/L. Both IRLML02 and IRLTITUS experienced a 6 µg/L increase between January 11th and January 15th, from 10.66 µg/L to 16.03 µg/L and 12.81 µg/L to 18.75 respectively. IRLI13 remained steady between a mean estimated ChlA of 9.25 µg/L and 9.92 µg/L. IRLI21 was the only station to experience a decline in estimated ChlA with a mean of 17.96 on January 15th. 


On January 9th the southern Mosquito Lagoon had an estimated ChlA median of 13.26 µg/L, 3rd Quartile of 22.11 µg/L, and maximum of 35.11 µg/L. This was an increase from the estimated ChlA median of 11.57 µg/L on January 7th. By January 15th the estimated ChlA median further increased to 21.08 µg/L, 3rd Quartile of 25.72 µg/L, and maximum of 33.08 µg/L. 


On January 9th the North NIRL had an estimated ChlA median of 8.06 µg/L, 3rd Quartile of 11.78 µg/L, and maximum of 30.82 µg/L. This was like the estimated ChlA median of 8.46 µg/L on January 7th. By January 15th the estimated ChlA median increased to 17.42 µg/L, 3rd Quartile of 22.44 µg/L, and maximum of 26.64 µg/L. 


There was an uptick in bloom activity in the Central NIRL, between Titusville and the State Road 528. On January 9th there was an estimated ChlA median of 13.28 µg/L, 3rd Quartile of 16.79 µg/L, and maximum of 28.06 µg/L. This was like the estimated ChlA median of 12.64 µg/L on January 7th. By January 15th the estimated ChlA median increased to 20.43 µg/L, 3rd Quartile of 27.93 µg/L, and maximum of 34.11 µg/L. 


The northern section of the Banana River from State Road 528 to the NASA Parkway East causeway on January 9th had an estimated ChlA median of 27.61 µg/L, 3rd Quartile of 32.88 µg/L, and maximum of 59.19 µg/L. This was an increase in the median estimated ChlA of 18.42 µg/L on January 7th. By January 15th the estimated ChlA median was 34.05 µg/L, 3rd Quartile of 39.83 µg/L, and maximum of 46.05 µg/L. 


The middle section of the Banana River from Cocoa Beach to the NASA Parkway East causeway on January 9th had an estimated ChlA median of 35.05 µg/L, 3rd Quartile of 45.92 µg/L, and maximum of 63.75 µg/L. This was an increase in the median estimated ChlA of 25.25 µg/L on January 7th. By January 15th the estimated ChlA median was 36.57 µg/L, 3rd Quartile of 57.03 µg/L, and maximum of 55.70 µg/L. 


The southern section of Banana River from Cocoa Beach to Patrick Space Force Base on January 9th had a median of 15.01 µg/L, 3rd Quartile of 19.16 µg/L, and maximum of 65.63 µg/L. This was an increase in the median estimated ChlA of 10.44 µg/L on January 7th. By January 15th the estimated ChlA median was 20.14 µg/L, 3rd Quartile of 25.96 µg/L, and maximum of 57.71 µg/L.


This suggests that the minor bloom activity in the Banana River which has been ongoing for over a month may have stabilized after the decrease following last week’s cold snap. The central section however remains elevated in comparison to the north and south. 


On January 9th in the South NIRL from State Roads 528 to 404 there was an estimated ChlA median of 9.78 µg/L, 3rd Quartile of 22.96 µg/L, and maximum of 58.03 µg/L. This was a decrease from the estimated ChlA median of 13.52 µg/L on January 5th. By January 15th the estimated ChlA had a median of 12.83 µg/L, 3rd Quartile of 24.24 µg/L, and maximum of 69.6 µg/L. 


On January 9th in the North Central IRL (CIRL) from State Road 404 to Turkey Creek there was an estimated ChlA median of 20.99 µg/L, 3rd Quartile of 30.38 µg/L, and maximum of 52.04 µg/L. This was similar to the estimated ChlA median of 20.52 µg/L on January 7th. By January 15th the estimated ChlA had a median of 17.26 µg/L, 3rd Quartile of 22.37 µg/L, and maximum of 55.15 µg/L. 

Table 3 - Sentinel 3A estimated Chlorophyll A (ChlA) statistics in Micrograms/Liter (µg/L) for January 11, 2022, over the St. John River Water Management District (SJRWMD) Indian River Lagoon (IRL) Continuous Monitoring Stations.

Station

Min ChlA

Max ChlA

Mean ChlA

IRLML02

9.03

11.92

10.66

IRLTITUS

10.60

14.18

12.81

IRLB04

26.95

32.73

29.15

IRLI13

8.45

10.19

9.25

IRLI21

23.90

37.19

29.39

Table 4 - Sentinel 3A estimated Chlorophyll A (ChlA) statistics in Micrograms/Liter (µg/L) for January 15, 2022, over the St. John River Water Management District (SJRWMD) Indian River Lagoon (IRL) Continuous Monitoring Stations.

Station

Min ChlA

Max ChlA

Mean ChlA

IRLML02

11.76

21.87

16.03

IRLTITUS

15.01

29.46

18.75

IRLB04

34.78

43.42

38.41

IRLI13

8.17

11.02

9.92

IRLI21

16.56

18.96

17.96

Methods

HAB’s observed by this project are defined as over 80 Micrograms/Liter (µg/L) Chlorophyll A (ChlA) (as estimated by a calibrated Normalized Difference Chlorophyll Index (NDCI)) and persistent across the week in review. The algorithms that transform the NDCI index value to estimated ChlA concentrations were developed using a second-order polynomial equation. The Sentinel 2 (S2) equation has a Root Square (R2) of 0.81 with a Root Mean Square Error (RMSE) of 14.14 ug/L of ChlA. The Sentinel 3 (S3) equation has an R2 of 0.92 and an RMSE of 9.92 ug/L ChlA. The RMSE is a measure of the accuracy of a model in estimating values, ChlA in this instance, where a lower value is indicative of higher accuracy. It does not identify if the model consistently over or underestimates the modeled values. The equations are below:


  • S2 Estimated ChlA = 297.36(NDCI)2 + 313.98(NDCI) + 36.152


  • S3 Estimated ChlA = 437.07(NDCI)2 + 348.98(NDCI) + 33.928

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