Funding & Acknowledgements

The data used in this analysis is from the Export Standardized Tables in the SEACAR Data Discovery Interface (DDI). Documents and information available through the SEACAR DDI are owned by the data provider(s) and users are expected to provide appropriate credit following accepted citation formats. Users are encouraged to access data to maximize utilization of gained knowledge, reducing redundant research and facilitating partnerships and scientific innovation.

With respect to documents and information available from SEACAR DDI, neither the State of Florida nor the Florida Department of Environmental Protection makes any warranty, expressed or implied, including the warranties of merchantability and fitness for a particular purpose arising out of the use or inability to use the data, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.

This report was funded in part, through a grant agreement from the Florida Department of Environmental Protection, Florida Coastal Management Program, by a grant provided by the Office for Coastal Management under the Coastal Zone Management Act of 1972, as amended, National Oceanic and Atmospheric Administration. The views, statements, findings, conclusions and recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the State of Florida, NOAA or any of their sub agencies.

Published: 2025-10-08

Threshold Filtering

Threshold filters, following the guidance of Florida Department of Environmental Protection’s (FDEP) Division of Environmental Assessment and Restoration (DEAR) are used to exclude specific results values from the SEACAR Analysis. Based on the threshold filters, Quality Assurance / Quality Control (QAQC) Flags are inserted into the SEACAR_QAQCFlagCode and SEACAR_QAQC_Description columns of the export data. The Include column indicates whether the QAQC Flag will also indicate that data are excluded from analysis. No data are excluded from the data export, but the analysis scripts can use the Include column to exclude data (1 to include, 0 to exclude).

Continuous Water Quality threshold values
Parameter Name Units Low Threshold High Threshold
Dissolved Oxygen mg/L -0.000001 50
Dissolved Oxygen Saturation % -0.000001 500
Salinity ppt -0.000001 70
Turbidity NTU -0.000001 4000
Water Temperature Degrees C -5.000000 45
pH None 2.000000 14
Discrete Water Quality threshold values
Parameter Name Units Low Threshold High Threshold
Ammonia, Un-ionized (NH3) mg/L - -
Ammonium, Filtered (NH4) mg/L - -
Chlorophyll a, Corrected for Pheophytin ug/L - -
Chlorophyll a, Uncorrected for Pheophytin ug/L - -
Colored Dissolved Organic Matter PCU - -
Dissolved Oxygen mg/L -0.000001 25
Dissolved Oxygen Saturation % -0.000001 310
Fluorescent Dissolved Organic Matter QSE - -
Light Extinction Coefficient m^-1 - -
NO2+3, Filtered mg/L - -
Nitrate (NO3) mg/L - -
Nitrite (NO2) mg/L - -
Nitrogen, organic mg/L - -
Phosphate, Filtered (PO4) mg/L - -
Salinity ppt -0.000001 70
Secchi Depth m 0.000001 50
Specific Conductivity mS/cm 0.005000 100
Total Kjeldahl Nitrogen mg/L - -
Total Nitrogen mg/L - -
Total Nitrogen mg/L - -
Total Phosphorus mg/L - -
Total Suspended Solids mg/L - -
Turbidity NTU - -
Water Temperature Degrees C 3.000000 40
pH None 2.000000 13
Quality Assurance Flags inserted based on threshold checks listed in Table 1 and 2
SEACAR QAQC Description Include SEACAR QAQCFlagCode
Exceeds maximum threshold 0 2Q
Below minimum threshold 0 4Q
Within threshold tolerance 1 6Q
No defined thresholds for this parameter 1 7Q

Value Qualifiers

Value qualifier codes included within the data are used to exclude certain results from the analysis. The data are retained in the data export files, but the analysis uses the Include column to filter the results.

STORET and WIN value qualifier codes

Value qualifier codes from STORET and WIN data are examined with the database and used to populate the Include column in data exports.

Value Qualifier codes excluded from analysis
Qualifier Source Value Qualifier Include MDL Description
STORET-WIN H 0 0 Value based on field kit determination; results may not be accurate
STORET-WIN J 0 0 Estimated value
STORET-WIN V 0 0 Analyte was detected at or above method detection limit
STORET-WIN Y 0 0 Lab analysis from an improperly preserved sample; data may be inaccurate

Discrete Water Quality Value Qualifiers

The following value qualifiers are highlighted in the Discrete Water Quality section of this report. An exception is made for Program 476 - Charlotte Harbor Estuaries Volunteer Water Quality Monitoring Network and data flagged with Value Qualifier H are included for this program only.

H - Value based on field kit determiniation; results may not be accurate. This code shall be used if a field screening test (e.g., field gas chromatograph data, immunoassay, or vendor-supplied field kit) was used to generate the value and the field kit or method has not been recognized by the Department as equivalent to laboratory methods.

I - The reported value is greater than or equal to the laboratory method detection limit but less than the laboratory practical quantitation limit.

Q - Sample held beyond the accepted holding time. This code shall be used if the value is derived from a sample that was prepared or analyzed after the approved holding time restrictions for sample preparation or analysis.

S - Secchi disk visible to bottom of waterbody. The value reported is the depth of the waterbody at the location of the Secchi disk measurement.

U - Indicates that the compound was analyzed for but not detected. This symbol shall be used to indicate that the specified component was not detected. The value associated with the qualifier shall be the laboratory method detection limit. Unless requested by the client, less than the method detection limit values shall not be reported

Systemwide Monitoring Program (SWMP) value qualifier codes

Value qualifier codes from the SWMP continuous program are examined with the database and used to populate the Include column in data exports. SWMP Qualifier Codes are indicated by QualifierSource=SWMP.

SWMP Value Qualifier codes
Qualifier Source Value Qualifier Include Description
SWMP -1 1 Optional parameter not collected
SWMP -2 0 Missing data
SWMP -3 0 Data rejected due to QA/QC
SWMP -4 0 Outside low sensor range
SWMP -5 0 Outside high sensor range
SWMP 0 1 Passed initial QA/QC checks
SWMP 1 0 Suspect data
SWMP 2 1 Reserved for future use
SWMP 3 1 Calculated data: non-vented depth/level sensorcorrection for changes in barometric pressure
SWMP 4 1 Historical: Pre-auto QA/QC
SWMP 5 1 Corrected data

Water Column

The water column habitat extends from the water’s surface to the bottom sediments, and it’s where fish, dolphins, crabs and people swim! So much life makes its home in the water column that the health of marine and coastal ecosystems, as well as human economies, depend on the condition of this vulnerable habitat. Local patterns of rainfall, temperature, winds and currents can rapidly change the condition of the water column, while global influences such as El Niño/La Niña, large-scale fluctuation in sea temperatures and climate change can have long-term effects. Inputs from the prosperity of our day-to-day lives including farming, mining and forestry, and emissions from power generation, automobiles and water treatment can also alter the health of the water column. Acting alone or together, each input can have complex and lasting effects on habitats and ecosystems.


SEACAR evaluates water column health with several essential parameters. These include nutrient surveys of nitrogen and phosphorus, and water quality assessments of salinity, dissolved oxygen, pH, and water temperature. Water clarity is evaluated with Secchi depth, turbidity, levels of chlorophyll a, total suspended solids, and colored dissolved organic matter. Additionally, the richness of nekton is indicated by the abundance of free-swimming fishes and macroinvertebrates like crabs and shrimps.

Seasonal Kendall-Tau Analysis

Indicators must have a minimum of five to ten years, depending on the habitat, of data within the geographic range of the analysis to be included in the analysis. Ten years of data are required for discrete parameters, and five years of data are required for continuous parameters. If there are insufficient years of data, the number of years of data available will be noted and labeled as “insufficient data to conduct analysis”. Further, for the preferred Seasonal Kendall-Tau test, there must be data from at least two months in common across at least two consecutive years within the RCP managed area being analyzed. Values that pass both of these tests will be included in the analysis and be labeled as Use_In_Analysis = TRUE. Any that fail either test will be excluded from the analyses and labeled as Use_In_Analysis = FALSE. The points for all Water Column plots displayed in this section are monthly averages. Trend significance will be denoted as “Significant Trend” (when p < 0.05), or “Non-significant Trend” (when p >= 0.05). Any parameters with insufficient data to perform Seasonal Kendall-Tau test will have their monthly averages plotted without a corresponding trend line.

Water Quality - Discrete

The following files were used in the discrete analysis:

  • Combined_WQ_WC_NUT_Chlorophyll_a_corrected_for_pheophytin-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Chlorophyll_a_uncorrected_for_pheophytin-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Colored_dissolved_organic_matter_CDOM-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Dissolved_Oxygen-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Dissolved_Oxygen_Saturation-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_pH-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Salinity-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Secchi_Depth-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Total_Nitrogen-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Total_Phosphorus-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Total_Suspended_Solids_TSS-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Turbidity-2025-Sep-04.txt

  • Combined_WQ_WC_NUT_Water_Temperature-2025-Sep-04.txt

Chlorophyll a, Corrected for Pheophytin - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average levels of chlorophyll a, corrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Scatter plot of monthly average levels of chlorophyll a, corrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Seasonal Kendall-Tau Trend Analysis for Chlorophyll a, Corrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly increasing trend 4920 31 1995 - 2025 1.1 0.1864 1.2607 0.0645 0

Monthly average chlorophyll a, corrected for pheophytin, increased by 0.06 µg/L per year, indicating a decrease in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Chlorophyll a, Corrected for Pheophytin
ProgramID N_Data YearMin YearMax
5002 4204 1995 2025
477 325 2016 2025
514 314 2013 2024
540 131 2017 2022
5008 28 2023 2025

Program names:

477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Chlorophyll a, Uncorrected for Pheophytin - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average levels of chlorophyll a, uncorrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Scatter plot of monthly average levels of chlorophyll a, uncorrected for pheophytin, over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed chlorophyll a (triangles) is included in the plot.
Seasonal Kendall-Tau Trend Analysis for Chlorophyll a, Uncorrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly increasing trend 6287 36 1990 - 2025 1.2 0.2221 0.7769 0.0633 0

Monthly average chlorophyll a, uncorrected for pheophytin, increased by 0.06 µg/L per year, indicating a decrease in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Chlorophyll a, Uncorrected for Pheophytin
ProgramID N_Data YearMin YearMax
5002 3621 1990 2025
514 2245 1993 2025
477 328 2016 2025
540 142 2017 2022
60 39 1986 2014
5008 29 2021 2025
103 22 2000 2015
118 12 2000 2010
115 7 2000 2004

Program names:

60 - Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey6
103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
118 - National Aquatic Resource Surveys, National Coastal Condition Assessment9
477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Colored Dissolved Organic Matter - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average colored dissolved organic matter (CDOM) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed CDOM (triangles) is included in the plot.
Scatter plot of monthly average colored dissolved organic matter (CDOM) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only laboratory-analyzed CDOM (triangles) is included in the plot.
Seasonal Kendall-Tau Trend Analysis for Colored Dissolved Organic Matter
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly increasing trend 2889 25 2001 - 2025 17.6 0.4847 -12.0515 1.8 0

Monthly average colored dissolved organic matter increased by 1.8 PCU per year, indicating a decrease in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Colored Dissolved Organic Matter
ProgramID N_Data YearMin YearMax
5002 1488 2014 2025
514 899 2001 2024
477 385 2016 2025
540 99 2017 2019
5008 50 2021 2025

Program names:

477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Dissolved Oxygen - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average dissolved oxygen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen values measured in the field (circles) are included in the plot.
Scatter plot of monthly average dissolved oxygen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Dissolved Oxygen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Field No significant trend 153189 39 1985 - 2025 6.71 0.0211 6.4604 0.0024 0.5065

Dissolved oxygen showed no detectable trend between 1985 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Dissolved Oxygen
ProgramID N_Data YearMin YearMax
5002 94123 1989 2025
69 57261 1996 2024
95 1163 1985 2018
477 385 2016 2025
540 121 2017 2022
60 113 1986 2014
118 53 2000 2021
5008 50 2021 2025
115 43 1991 2004
103 8 2015 2015

Program names:

60 - Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey6
69 - Fisheries-Independent Monitoring (FIM) Program10
95 - Harmful Algal Bloom Marine Observation Network11
103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
118 - National Aquatic Resource Surveys, National Coastal Condition Assessment9
477 - Suwannee River Water Management District Water Resource Monitoring Program1
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Dissolved Oxygen Saturation - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average dissolved oxygen saturation over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen saturation values measured in the field (circles) are included in the plot.
Scatter plot of monthly average dissolved oxygen saturation over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only dissolved oxygen saturation values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Dissolved Oxygen Saturation
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Field Significantly decreasing trend 1912 21 1999 - 2025 67 -0.2126 84.0559 -0.7841 0.0007

Monthly average dissolved oxygen saturation decreased by 0.78% per year.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Dissolved Oxygen Saturation
ProgramID N_Data YearMin YearMax
5002 1511 1999 2025
477 385 2016 2025
5008 49 2021 2025
95 3 2016 2018

Program names:

95 - Harmful Algal Bloom Marine Observation Network11
477 - Suwannee River Water Management District Water Resource Monitoring Program1
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

pH - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average pH over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only pH values measured in the field (circles) are included in the plot.
Scatter plot of monthly average pH over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only pH values measured in the field (circles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for pH
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Field No significant trend 110554 38 1964 - 2025 8 -0.0112 7.8931 -0.0002 0.8406

pH showed no detectable trend between 1964 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for pH
ProgramID N_Data YearMin YearMax
69 57154 1996 2024
5002 52139 1989 2025
95 776 1964 2018
477 385 2016 2025
540 85 2017 2022
5008 48 2021 2025
115 43 1991 2004
103 8 2015 2015

Program names:

69 - Fisheries-Independent Monitoring (FIM) Program10
95 - Harmful Algal Bloom Marine Observation Network11
103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
477 - Suwannee River Water Management District Water Resource Monitoring Program1
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Salinity - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average salinity over time. If the time series included ten or more years of discrete observations, significant (blue) or non-significant (magenta) trend lines are also shown. Discrete salinity values derived from grab samples analyzed in the field (circles) or the laboratory (triangles) are both included in the plot.
Scatter plot of monthly average salinity over time. If the time series included ten or more years of discrete observations, significant (blue) or non-significant (magenta) trend lines are also shown. Discrete salinity values derived from grab samples analyzed in the field (circles) or the laboratory (triangles) are both included in the plot.
Seasonal Kendall-Tau Trend Analysis for Salinity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
All Significantly decreasing trend 158388 41 1964 - 2025 23.3 -0.0966 24.6595 -0.0556 0.0062

Monthly average salinity decreased by 0.06 ppt per year.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Salinity
ProgramID N_Data YearMin YearMax
5002 97556 1990 2025
69 57414 1996 2024
560 1474 2003 2024
95 1289 1964 2018
477 356 2016 2025
540 132 2017 2022
60 109 1986 2014
118 51 2015 2021
5008 51 2021 2025
115 43 1991 2004

Program names:

60 - Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey6
69 - Fisheries-Independent Monitoring (FIM) Program10
95 - Harmful Algal Bloom Marine Observation Network11
115 - Environmental Monitoring Assessment Program8
118 - National Aquatic Resource Surveys, National Coastal Condition Assessment9
477 - Suwannee River Water Management District Water Resource Monitoring Program1
540 - Shellfish Harvest Area Classification Program3
560 - Big Bend Seagrasses & Nature Coast Aquatic Preserves - Seagrass Monitoring12
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Secchi Depth - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average Secchi depth over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Secchi depth is only measured in the field (circles).
Scatter plot of monthly average Secchi depth over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Secchi depth is only measured in the field (circles).
Seasonal Kendall-Tau Trend Analysis for Secchi Depth
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Field Significantly increasing trend 62713 37 1986 - 2025 -0.9 0.1283 -1.372 0.006 0.0004

Monthly average Secchi depth became shallower by 0.01 m per year, indicating a decrease in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Secchi Depth
ProgramID N_Data YearMin YearMax
69 57396 1996 2024
5002 2592 1992 2025
514 2276 1993 2025
477 382 2016 2025
5008 44 2021 2025
115 21 1991 2004
60 6 1986 2009
103 4 2001 2015

Program names:

60 - Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey6
69 - Fisheries-Independent Monitoring (FIM) Program10
103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Total Nitrogen - Discrete

Total Nitrogen Calculation:

The logic for calculated Total Nitrogen was provided by Kevin O’Donnell and colleagues at FDEP (with the help of Jay Silvanima, Watershed Monitoring Section). The following logic is used, in this order, based on the availability of specific nitrogen components.

  1. TN = TKN + NO3O2;
  2. TN = TKN + NO3 + NO2;
  3. TN = ORGN + NH4 + NO3O2;
  4. TN = ORGN + NH4 + NO2 + NO3;
  5. TN = TKN + NO3;
  6. TN = ORGN + NH4 + NO3;

Additional Information:

  • Rules for use of sample fraction:
    • Florida Department of Environmental Protection (FDEP) report that if both “Total” and “Dissolved” components are reported, only “Total” is used. If the total is not reported, then the dissolved components are used as a best available replacement.
    • Total nitrogen calculations are done using nitrogen components with the same sample fraction, nitrogen components with mixed total/dissolved sample fractions are not used. In other words, total nitrogen can be calculated when TKN and NO3O2 are both total sample fractions, or when both are dissolved sample fractions. Future calculations of total nitrogen values may be based on components with mixed sample fractions.
  • Values inserted into data:
    • ParameterName = “Total Nitrogen”
    • SEACAR_QAQCFlagCode = “1Q”
    • SEACAR_QAQC_Description = “SEACAR Calculated”

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average total nitrogen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only nitrogen values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total nitrogen over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only nitrogen values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Total Nitrogen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly increasing trend 8222 36 1990 - 2025 0.466 0.2315 0.3715 0.0073 0

Monthly average total nitrogen increased by 0.01 mg/L per year.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Total Nitrogen
ProgramID N_Data YearMin YearMax
5002 5630 1990 2025
514 2391 1993 2024
540 131 2017 2022
103 36 2000 2006
5008 30 2021 2025
115 5 2000 2004
477 3 2017 2017

Program names:

103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Total Phosphorus - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average total phosphorus over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only phosphorus values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total phosphorus over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only phosphorus values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Total Phosphorus
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly increasing trend 6513 34 1992 - 2025 0.032 0.6035 0.0044 0.0016 0

Monthly average total phosphorus increased by less than 0.01 mg/L per year.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Total Phosphorus
ProgramID N_Data YearMin YearMax
5002 3709 1992 2025
514 2374 1993 2024
477 385 2016 2025
540 131 2017 2022
103 37 2000 2015
5008 29 2021 2025
115 5 2000 2004

Program names:

103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
115 - Environmental Monitoring Assessment Program8
477 - Suwannee River Water Management District Water Resource Monitoring Program1
514 - Florida LAKEWATCH Program2
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Total Suspended Solids - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average total suspended solids (TSS) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only TSS values obtained from laboratory analyses (triangles) are included in the plot.
Scatter plot of monthly average total suspended solids (TSS) over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only TSS values obtained from laboratory analyses (triangles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Total Suspended Solids
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly decreasing trend 3003 36 1990 - 2025 4 -0.3001 5.156 -0.0667 0

Monthly average total suspended solids decreased by 0.07 mg/L per year, indicating an increase in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Total Suspended Solids
ProgramID N_Data YearMin YearMax
5002 2996 1990 2025
477 28 2021 2023

Program names:

477 - Suwannee River Water Management District Water Resource Monitoring Program1
5002 - Florida STORET / WIN4

Turbidity - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average turbidity over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only turbidity values measured in the laboratory (triangles) are included in the plot.
Scatter plot of monthly average turbidity over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only turbidity values measured in the laboratory (triangles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Turbidity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Lab Significantly decreasing trend 42959 36 1990 - 2025 3.4 -0.1016 4.6754 -0.034 0.0033

Monthly average turbidity decreased by 0.03 NTU per year, indicating an increase in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Turbidity
ProgramID N_Data YearMin YearMax
5002 42694 1990 2025
477 678 2016 2025
540 35 2019 2022
103 11 2005 2006

Program names:

103 - EPA STOrage and RETrieval Data Warehouse (STORET)/WQX7
477 - Suwannee River Water Management District Water Resource Monitoring Program1
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4

Water Temperature - Discrete

Seasonal Kendall-Tau Trend Analysis

Scatter plot of monthly average water temperature over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only water temperature measurements taken in the field (circles) are included in the plot.
Scatter plot of monthly average water temperature over time. If the time series included ten or more years of discrete observations, a significant (blue) or non-significant (magenta) trend line is also shown. Only water temperature measurements taken in the field (circles) are included in the plot.
Seasonal Kendall-Tau Trend Analysis for Water Temperature
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
Field Significantly increasing trend 159977 42 1964 - 2025 24.1 0.2258 21.1463 0.0422 0

Monthly average water temperature increased by 0.04°C per year.

Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of discrete water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Programs contributing data for Water Temperature
ProgramID N_Data YearMin YearMax
5002 100539 1989 2025
69 57437 1996 2024
95 1377 1964 2018
477 385 2016 2025
540 133 2017 2022
60 119 1986 2014
5008 49 2021 2025
115 43 1991 2004

Program names:

60 - Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey6
69 - Fisheries-Independent Monitoring (FIM) Program10
95 - Harmful Algal Bloom Marine Observation Network11
115 - Environmental Monitoring Assessment Program8
477 - Suwannee River Water Management District Water Resource Monitoring Program1
540 - Shellfish Harvest Area Classification Program3
5002 - Florida STORET / WIN4
5008 - Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region5

Water Quality - Continuous

The following files were used in the continuous analysis:

  • Combined_WQ_WC_NUT_cont_Dissolved_Oxygen_NW-2025-Sep-19.txt

  • Combined_WQ_WC_NUT_cont_Dissolved_Oxygen_Saturation_NW-2025-Sep-19.txt

  • Combined_WQ_WC_NUT_cont_pH_NW-2025-Sep-19.txt

  • Combined_WQ_WC_NUT_cont_Salinity_NW-2025-Sep-19.txt

  • Combined_WQ_WC_NUT_cont_Turbidity_NW-2025-Sep-19.txt

  • Combined_WQ_WC_NUT_cont_Water_Temperature_NW-2025-Sep-19.txt

Continuous monitoring locations in Big Bend Seagrasses Aquatic Preserve

Station overview for Continuous parameters by Program
ProgramID ProgramLocationID Years of Data Use in Analysis Parameters
7 02313700 8 TRUE DO , pH , Sal
7 02313700 24 TRUE TempW
7 02323566 12 TRUE DO , pH , TempW
7 02323592 16 TRUE Sal
7 02323592 26 TRUE TempW
7 02326050 5 TRUE TempW
7 02326516 6 TRUE DO , pH , TempW
7 02326526 10 TRUE DO , pH , TempW
7 02326550 8 TRUE Sal
7 02326550 24 TRUE TempW
7 02327022 3 FALSE TempW
7 291652083064100 1 FALSE Sal , TempW
7 291842083085100 1 FALSE Sal , TempW
471 BBSCK 1 FALSE DO , DOS , pH , Sal , Turb , TempW
471 BBSDB 10 TRUE DO , DOS , pH , Sal , Turb , TempW
471 BBSSK 12 TRUE DO , DOS , pH , Sal , Turb , TempW
471 BBSST 6 TRUE DO , DOS , pH , Sal , Turb , TempW
471 BBSSW 8 TRUE DO , DOS , pH , Sal , Turb , TempW

Program names:

7 - National Water Information System13
471 - Big Bend Seagrasses Aquatic Preserves Continuous Water Quality Monitoring14

Map showing continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. Sites marked as Use In Analysis (green) are featured in this report.
Map showing continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. Sites marked as Use In Analysis (green) are featured in this report.

Dissolved Oxygen - Continuous

Scatter plot of monthly average dissolved oxygen over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average dissolved oxygen over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Dissolved Oxygen - All Stations
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
02326526 No significant trend 3342 10 2016 - 2025 6.7 0.14 6.61 0.04 0.05
02323566 Significantly decreasing trend 3879 12 2014 - 2025 1.1 -0.38 1.49 -0.06 0
02313700 No significant trend 2425 8 2018 - 2025 5.5 -0.12 5.93 -0.03 0.17
02326516 No significant trend 1583 6 2020 - 2025 2.6 -0.2 2.72 -0.03 0.13
BBSDB No significant trend 184327 10 2007 - 2016 7.3 -0.05 7.46 -0.01 0.61
BBSCK Insufficient data to calculate trend 14788 1 2023 - 2023 6.7 - - - -
BBSST No significant trend 146149 6 2019 - 2024 6.9 -0.01 6.71 0 1
BBSSK Significantly increasing trend 134287 10 2004 - 2015 7.1 0.28 6.6 0.09 0
BBSSW No significant trend 182327 8 2009 - 2016 6.2 0 6 0 1

At one program location, monthly average dissolved oxygen increased by 0.09 mg/L per year. At one program location, monthly average dissolved oxygen decreased by 0.06 mg/L per year. No detectable change in monthly average dissolved oxygen was observed at six locations. There was insufficient data to fit a model for one location.

Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen Saturation - Continuous

Scatter plot of monthly average dissolved oxygen saturation over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average dissolved oxygen saturation over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Dissolved Oxygen Saturation - All Stations
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
BBSDB Significantly decreasing trend 183530 10 2007 - 2016 97.6 -0.3 100.88 -0.81 0
BBSCK Insufficient data to calculate trend 19834 1 2023 - 2023 95.7 - - - -
BBSSK No significant trend 134196 10 2004 - 2015 91.8 0.12 93.37 0.36 0.26
BBSST No significant trend 149203 6 2019 - 2024 93.3 0.08 92.61 0.26 0.5
BBSSW No significant trend 182158 8 2009 - 2016 75.8 -0.05 79.14 -0.25 0.68

At one program location, monthly average dissolved oxygen saturation decreased by 0.81% per year. No detectable change in monthly average dissolved oxygen saturation was observed at three locations. There was insufficient data to fit a model for one location.

Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

pH - Continuous

Scatter plot of monthly average pH over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average pH over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for pH - All Stations
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
02326516 Significantly increasing trend 1485 6 2020 - 2025 7.7 0.4 7.63 0.02 0
02326526 Significantly increasing trend 3148 10 2016 - 2025 8.0 0.19 7.97 0.02 0.02
02323566 No significant trend 3666 12 2014 - 2025 7.2 -0.13 7.22 0 0.06
02313700 No significant trend 2388 8 2018 - 2025 7.6 0.16 7.6 0.01 0.11
BBSDB Significantly decreasing trend 250183 10 2007 - 2016 8.1 -0.28 8.17 -0.02 0
BBSCK Insufficient data to calculate trend 18185 1 2023 - 2023 8.1 - - - -
BBSST No significant trend 153335 6 2019 - 2024 8.0 -0.01 7.95 0 0.94
BBSSK Significantly decreasing trend 168278 10 2004 - 2015 8.1 -0.37 8.28 -0.04 0
BBSSW Significantly decreasing trend 224733 8 2009 - 2016 7.6 -0.29 7.8 -0.06 0

At two program locations, monthly average pH increased by 0.02 pH units per year. At three program locations, monthly average pH decreased between 0.02 and 0.06 pH units per year. No detectable change in monthly average pH was observed at three locations. There was insufficient data to fit a model for one location.

Map showing location of ph continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of ph continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Salinity - Continuous

Scatter plot of monthly average salinity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average salinity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Salinity - All Stations
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
02323592 Significantly decreasing trend 6064 16 2000 - 2015 0.1 -0.13 0.18 0 0.02
291652083064100 Insufficient data to calculate trend 827 1 2000 - 2000 6.7 - - - -
02326550 Significantly increasing trend 2507 8 2002 - 2009 1.7 0.48 0.09 0.76 0
02313700 Significantly increasing trend 1601 7 2002 - 2009 2.1 0.52 0.1 0.53 0
291842083085100 Insufficient data to calculate trend 584 1 2000 - 2000 3.7 - - - -
BBSDB Significantly decreasing trend 265544 10 2007 - 2016 30.6 -0.53 33.78 -0.75 0
BBSCK Insufficient data to calculate trend 14782 1 2023 - 2023 29.2 - - - -
BBSSK Significantly decreasing trend 178356 10 2004 - 2015 29.6 -0.22 30.77 -0.21 0.02
BBSST No significant trend 156720 6 2019 - 2024 28.5 0.08 27.59 0.15 0.52
BBSSW Significantly decreasing trend 221696 8 2009 - 2016 7.5 -0.23 10.39 -0.65 0.02

At two program locations, monthly average salinity increased by 0.53 ppt per year at one site and by 0.76 ppt per year at the other. At four program locations, monthly average salinity decreased between less than 0.01 and 0.75 ppt per year. No detectable change in monthly average salinity was observed at one location. There was insufficient data to fit a model for three locations.

Map showing location of salinity continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of salinity continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Turbidity - Continuous

Scatter plot of monthly average turbidity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average turbidity over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Turbidity - All Stations
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
BBSDB Significantly increasing trend 224613 10 2007 - 2016 1 0.49 1.47 1.22 0
BBSCK Insufficient data to calculate trend 23243 1 2023 - 2023 7 - - - -
BBSSK No significant trend 165043 10 2004 - 2015 5 0.11 6.35 0.3 0.19
BBSST Significantly decreasing trend 157393 6 2019 - 2024 4 -0.31 6.73 -0.55 0.01
BBSSW Significantly decreasing trend 202699 8 2009 - 2016 6 -0.35 12.41 -0.99 0

At one program location, monthly average turbidity increased by 1.22 NTU per year. At two program locations, monthly average turbidity decreased by 0.55 NTU per year at one site and by 0.99 NTU per year at the other. No detectable change in monthly average turbidity was observed at one location. There was insufficient data to fit a model for one location.

Map showing location of turbidity continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of turbidity continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Temperature - Continuous - Program 7

Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Water Temperature - Program 7
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
02326050 Significantly increasing trend 1695 5 2021 - 2025 21.9 0.32 20.48 0.32 0.01
02326526 No significant trend 3399 10 2016 - 2025 21.6 -0.06 21.21 -0.01 0.47
02313700 Significantly increasing trend 4097 15 2002 - 2025 23.0 0.14 22.58 0.03 0.04
02323592 No significant trend 13025 23 2000 - 2025 23.3 -0.02 22.57 0 0.72
02326516 Significantly increasing trend 1616 6 2020 - 2025 20.6 0.32 20.54 0.02 0.01
02323566 Significantly increasing trend 4020 12 2014 - 2025 22.6 0.77 22.39 0.04 0
02326550 Significantly increasing trend 4930 13 2002 - 2025 22.4 0.21 21.25 0.04 0
291842083085100 Insufficient data to calculate trend 542 1 2000 - 2000 23.1 - - - -
02327022 Insufficient data to calculate trend 658 3 2023 - 2025 21.3 - - - -
291652083064100 Insufficient data to calculate trend 473 1 2000 - 2000 26.1 - - - -

At five program locations, monthly average water temperature increased between 0.02 and 0.32°C per year. At one program location, monthly average water temperature decreased by 0.37°C per year. No detectable change in monthly average water temperature was observed at five locations. There was insufficient data to fit a model for four locations.

Water Temperature - Continuous - Program 471

Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Scatter plot of monthly average water temperature over time at continuously monitored program locations. Each location is analyzed separately, with significant (blue) or non-significant (magenta) trend lines shown for time series that included five or more years of observations.
Seasonal Kendall-Tau Results for Water Temperature - Program 471
Station Statistical Trend Sample Count Years with Data Period of Record Median tau Sen Intercept Sen Slope p
BBSDB No significant trend 265988 10 2007 - 2016 23.2 0.08 22.34 0.04 0.29
BBSCK Insufficient data to calculate trend 22232 1 2023 - 2023 26.4 - - - -
BBSSK Significantly decreasing trend 179213 10 2004 - 2015 21.7 -0.33 25.19 -0.37 0
BBSST No significant trend 163227 6 2019 - 2024 23.5 0.1 24.44 0.1 0.52
BBSSW No significant trend 227996 8 2009 - 2016 23.7 0.02 23.09 0.01 0.9

At five program locations, monthly average water temperature increased between 0.02 and 0.32°C per year. At one program location, monthly average water temperature decreased by 0.37°C per year. No detectable change in monthly average water temperature was observed at five locations. There was insufficient data to fit a model for four locations.

Map showing location of water temperature continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of water temperature continuous water quality sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Submerged Aquatic Vegetation

The data file used is: All_SAV_Parameters-2025-Sep-04.txt

Submerged aquatic vegetation (SAV) refers to plants and plant-like macroalgae species that live entirely underwater. The two primary categories of SAV inhabiting Florida estuaries are benthic macroalgae and seagrasses. They often grow together in dense beds or meadows that carpet the seafloor. Macroalgae include multicellular species of green, red and brown algae that often live attached to the substrate by a holdfast. They tend to grow quickly and can tolerate relatively high nutrient levels, making them a threat to seagrasses and other benthic habitats in areas with poor water quality. In contrast, seagrasses are grass-like, vascular, flowering plants that are attached to the seafloor by extensive root systems. Seagrasses occur throughout the coastal areas of Florida, including protected bays and lagoons as well as deeper offshore waters on the continental shelf. Seagrasses have taken advantage of the broad, shallow shelf and clear water to produce two of the most extensive seagrass beds anywhere in continental North America.

Parameters

Percent Cover measures the fraction of an area of seafloor that is covered by SAV, usually estimated by evaluating multiple small areas of seafloor. Percent cover is often estimated for total SAV, individual types of vegetation (seagrass, attached algae, drift algae) and individual species.

Frequency of Occurrence was calculated as the number of times a taxon was observed in a year divided by the number of sampling events, multiplied by 100. Analysis is conducted at the quadrat level and is inclusive of all quadrats (i.e., quadrats evaluated using Braun-Blanquet, modified Braun-Blanquet, and percent cover.”

Species

Turtle grass (Thalassia testudinum) is the largest of the Florida seagrasses, with longer, thicker blades and deeper root structures than any of the other seagrasses. It is considered a climax seagrass species.

Shoal grass (Halodule wrightii) is an early colonizer of vegetated areas and usually grows in water too shallow for other species except widgeon grass. It can often tolerate larger salinity ranges than other seagrass species. Shoal grass is characterized by thin, flat blades, that are narrower than turtle grass blades.

Manatee grass (Syringodium filiforme) is easily recognizable because its leaves are thin and cylindrical instead of the flat, ribbon-like form shared by many other seagrass species. The leaves can grow up to half a meter in length. Manatee grass is usually found in mixed seagrass beds or small, dense monospecific patches.

Widgeon grass (Ruppia maritima) grows in both fresh and salt water and is widely distributed throughout Florida’s estuaries in less saline areas, particularly in inlets along the east coast. This species resembles shoal grass in certain environments but can be identified by the pointed tips of its leaves.

Three species of Halophila spp. are found in Florida - Star grass (Halophila engelmannii), Paddle grass (Halophila decipiens), and Johnson’s seagrass (Halophila johnsonii). These are smaller, more fragile seagrasses than other Florida species and are considered ephemeral. They grow along a single long rhizome, with short blades. These species are not well-studied, although surveys are underway to define their ecological roles.

Notes

Star grass, Paddle grass, and Johnson’s seagrass will be grouped together and listed as Halophila spp. in the following managed areas. This is because several surveys did not specify to the species level:

  • Banana River Aquatic Preserve

  • Indian River-Malabar to Vero Beach Aquatic Preserve

  • Indian River-Vero Beach to Ft. Pierce Aquatic Preserve

  • Jensen Beach to Jupiter Inlet Aquatic Preserve

  • Loxahatchee River-Lake Worth Creek Aquatic Preserve

  • Mosquito Lagoon Aquatic Preserve

  • Biscayne Bay Aquatic Preserve

  • Florida Keys National Marine Sanctuary

Maps showing the temporal scope of SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve by Program name.
Maps showing the temporal scope of SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve by Program name.

Click here to view spatio-temporal plots on GitHub.

Sampling locations by Program:

Map showing SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Map showing SAV sampling sites within the boundaries of Big Bend Seagrasses Aquatic Preserve. The point size reflects the number of samples at a given sampling site.
Program Information for Submerged Aquatic Vegetation
ProgramID N-Data YearMin YearMax method Sample Locations
559 537 2012 2018 Modified Braun Blanquet 195
560 19753 2000 2024 Modified Braun Blanquet 100
560 4271 2022 2024 Percent Cover 100

Program names:

559 - Northern Big Bend Seagrass Monitoring15
560 - Big Bend Seagrasses & Nature Coast Aquatic Preserves - Seagrass Monitoring12
560 - Big Bend Seagrasses & Nature Coast Aquatic Preserves - Seagrass Monitoring12

Scatter plots of median percent cover of submerged aquatic vegetation over time by group. Plots for time series that included five or more years of observations show the estimated trend as a blue line.
Scatter plots of median percent cover of submerged aquatic vegetation over time by group. Plots for time series that included five or more years of observations show the estimated trend as a blue line.
Trends in median percent cover for various seagrass species in Big Bend Seagrasses Aquatic Preserve - simplified
Trends in median percent cover for various seagrass species in Big Bend Seagrasses Aquatic Preserve - simplified
Percent Cover Trend Analysis for Big Bend Seagrasses Aquatic Preserve
CommonName Trend Significance (0.05) Period of Record LME-Intercept LME-Slope p
Drift algae Significantly increasing trend 2000 - 2024 5.453911 0.8127330 0.0000009
Shoal grass Significantly decreasing trend 2000 - 2024 24.829747 -0.4314551 0.0001280
Star grass No significant trend 2000 - 2024 18.552789 -0.1347727 0.3089913
No grass in quadrat Model did not fit the available data 2004 - 2024 - - -
Widgeon grass No significant trend 2001 - 2024 25.939604 -0.2793089 0.5982584
Manatee grass Significantly decreasing trend 2000 - 2024 35.945396 -0.4271771 0.0000536
Turtle grass Significantly decreasing trend 2000 - 2024 42.516006 -0.4815112 0.0000000

An annual increase in percent cover was observed for drift algae (0.8%). Annual decreases in percent cover were observed for manatee grass (-0.4%), shoal grass (-0.4%), and turtle grass (-0.5%). No detectable change in percent cover was observed for star grass and widgeon grass.

Frequency of occurrence for various seagrass species in Big Bend Seagrasses Aquatic Preserve
Frequency of occurrence for various seagrass species in Big Bend Seagrasses Aquatic Preserve

SAV Water Column Analysis

The following parameters are available for Big Bend Seagrasses Aquatic Preserve within the SAV_WC_Report:

  • Colored Disolved Organic Matter

  • Chlorophyll a

  • Dissolved Oxygen

  • Dissolved Oxygen Saturation

  • pH

  • Salinity

  • Secchi Depth

  • Water Temperature

  • Total Nitrogen

  • Total Suspended Solids

  • Turbidity

Access the reports here: DRAFT_SAV_WC_Report_2024-11-20.pdf

Coastal Wetlands

The data file used is: All_CW_Parameters-2025-Sep-04.txt

Line graph of annual average coastal wetlands species richness over time for mangroves and associates (triangles), marsh (squares), and marsh succulents (circles). If the time series by species group included more than one year of observations, a line connects data points for visualization.
Line graph of annual average coastal wetlands species richness over time for mangroves and associates (triangles), marsh (squares), and marsh succulents (circles). If the time series by species group included more than one year of observations, a line connects data points for visualization.
Coastal Wetlands Species Richness
Species Group Sample Count Number of Years Period of Record Median N of Taxa Mean N of Taxa
Marsh 6 2 2013 - 2016 2 2.17

Between 2013 and 2016, the median annual number of species for marsh was 2 based on 6 observations.

Map showing location of coastal wetlands sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of coastal wetlands sampling locations within the boundaries of Big Bend Seagrasses Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Species list

Acanthophora muscoides1 Drift algae1 Persicaria hydropiperoides
Acetabularia crenulata1 Drift red algae1 Pluchea camphorata
Anadyomene stellata1 Eupatorium mikanioides Polysiphonia sp.1
Avrainvillea levis1 Gracilaria sp.1 Ruppia maritima1
Caulerpa1 Halimeda incrassata1 Sagittaria graminea
Caulerpa ashmeadii1 Halodule wrightii1 Sagittaria lancifolia lancifolia
Caulerpa cupressoides1 Halophila engelmannii1 Sargassum sp.1
Caulerpa mexicana1 Juncus roemerianus2 Sargassum spp.1
Caulerpa paspaloides1 Laurencia spp.1 Schoenoplectus tabernaemontani
Caulerpa prolifera1 Ludwigia repens Spartina alterniflora2
Caulerpa racemosa1 Lythrum lineare Spyridia1
Caulerpa sertularioides1 No grass in quadrat1 Syringodium filiforme1
Caulerpa spp.1 Padina1 Thalassia testudinum1
Cladium mariscus Padina gymnospora1 Udotea flabellum1
Codium isthmocladum1 Penicillus capitatus1 Ulva sp.1
Digenea simplex1 Penicillus dumetosus1 Unidentified species
Distichlis spicata2 Penicillus spp.1 Yuzurua poiteaui1

1 - Submerged Aquatic Vegetation, 2 - Coastal Wetlands

References

1.
Suwannee River Water Management District (SRWMD). Suwannee River Water Management District Water Resource Monitoring Program. (2024).
2.
University of Florida (UF); Institute of Food and Agricultural Sciences. Florida LAKEWATCH Program. (2024).
3.
Florida Department of Agriculture and Consumer Services (FDACS) - Division of Aquaculture. Shellfish Harvest Area Classification Program. (2022).
4.
Florida Department of Environmental Protection (DEP). Florida STORET / WIN. (2024).
5.
University of Florida (UF); Florida Department of Environmental Protection (DEP); Office of Resilience and Coastal Protection (RCP); Big Bend Seagrasses Aquatic Preserves / Nature Coast Aquatic Preserve. Project COAST (Coastal Assessment Team) - Springs Coast Ecosystem Region. (2024).
6.
Gulf States Marine Fisheries Commission. Southeast Area Monitoring and Assessment Program (SEAMAP) - Gulf of Mexico Fall & Summer Shrimp/Groundfish Survey. (2016).
7.
U.S. Environmental Protection Agency (EPA). EPA STOrage and RETrieval Data Warehouse (STORET)/WQX. (2023).
8.
U.S. Environmental Protection Agency (EPA); Office of Research and Development. Environmental Monitoring Assessment Program. (2004).
9.
U.S. Environmental Protection Agency (EPA); Office of Water; National Oceanic and Atmospheric Administration (NOAA); U.S. Geological Survey (USGS); U.S. Fish and Wildlife Service (USFWS); National Estuary Program (NEP); coastal states. National Aquatic Resource Surveys, National Coastal Condition Assessment. (2021).
10.
Florida Fish and Wildlife Conservation Commission (FWC). Fisheries-Independent Monitoring (FIM) Program. (2022).
11.
Florida Fish and Wildlife Conservation Commission (FWC); Florida Fish and Wildlife Research Institute (FWRI). Harmful Algal Bloom Marine Observation Network. (2018).
12.
Florida Department of Environmental Protection (DEP); Office of Resilience and Coastal Protection (RCP); Big Bend Seagrasses Aquatic Preserves; University of Florida - Nature Coast Aquatic Preserve. Big Bend Seagrasses & Nature Coast Aquatic Preserves - Seagrass Monitoring. (2024).
13.
U.S. Geological Survey (USGS). National Water Information System. (2024).
14.
Florida Department of Environmental Protection (DEP); Office of Resilience and Coastal Protection (RCP); Big Bend Seagrasses Aquatic Preserves. Big Bend Seagrasses Aquatic Preserves Continuous Water Quality Monitoring. (2024).
15.
Florida Fish and Wildlife Conservation Commission (FWC); Florida Fish and Wildlife Research Institute (FWRI). Northern Big Bend Seagrass Monitoring. (2018).