Indicators

Nutrients

Total Nitrogen - Discrete

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 Results for - Total Nitrogen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 1079 27 1997 - 2025 0.419 0.03332 0.36456 0.00156 0.5048

Total nitrogen showed no detectable trend between 1997 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Total Phosphorus - Discrete

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 Results for - Total Phosphorus
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 1615 27 1997 - 2025 0.067 0.01638 0.06274 0.00011 0.6539

Total phosphorus showed no detectable trend between 1997 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Quality

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 - Dissolved Oxygen
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
02231291 Insufficient data to calculate trend 689 3 2014 - 2016 5.70 - - - -
NECI Insufficient data to calculate trend 62230 3 2023 - 2025 5.80 - - - -
NEHM Insufficient data to calculate trend 111776 4 2022 - 2025 5.50 - - - -
NEKD No significant trend 110958 8 2004 - 2011 6.40 -0.04 6.59 -0.02 0.5607
NELC Significantly decreasing trend 95860 7 2005 - 2011 5.60 -0.34 5.93 -0.11 0.0014
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 5.80 - - - -
NCB19020038 No significant trend 34476 5 2015 - 2019 6.16 -0.03 6.23 -0.03 0.6108
NCBARD16 Insufficient data to calculate trend 7417 2 2015 - 2016 5.08 - - - -
NCBNRCM No significant trend 35477 5 2015 - 2019 5.79 0.05 5.78 0.01 0.797

At one program location, monthly average dissolved oxygen decreased by 0.11 mg/L per year. No detectable change in monthly average dissolved oxygen was observed at three locations. There was insufficient data to fit a model for five locations.

Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen - Discrete

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 Results for - Dissolved Oxygen
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly decreasing trend 22688 30 1995 - 2025 6.8 -0.27269 7.32517 -0.03694 0

Monthly average dissolved oxygen decreased by 0.04 mg/L per year.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes 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 - Dissolved Oxygen Saturation
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
NECI Insufficient data to calculate trend 62577 3 2023 - 2025 80.50 - - - -
NEHM Insufficient data to calculate trend 114458 4 2022 - 2025 71.50 - - - -
NEKD No significant trend 110983 8 2004 - 2011 89.10 0 87.49 -0.04 0.9338
NELC Significantly decreasing trend 95868 7 2005 - 2011 77.90 -0.27 78.93 -1.6 0.0111
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 73.20 - - - -
NCB19020038 No significant trend 34438 5 2015 - 2019 87.06 -0.16 86.02 -0.6 0.1268
NCBARD16 Insufficient data to calculate trend 7417 2 2015 - 2016 74.44 - - - -
NCBNRCM No significant trend 35240 5 2015 - 2019 82.06 -0.05 81.1 -0.14 0.797

At one program location, monthly average dissolved oxygen saturation decreased by 1.60% 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 four locations.

Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Dissolved Oxygen Saturation - Discrete

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 Results for - Dissolved Oxygen Saturation
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field No significant trend 1461 20 2000 - 2025 88 -0.08578 88.7588 -0.08849 0.1199

Dissolved oxygen saturation showed no detectable trend between 2000 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Salinity - Discrete

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 Results for - Salinity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
All No significant trend 22797 30 1980 - 2025 30.5 -0.0641 30.36939 -0.05737 0.0985

Salinity showed no detectable trend between 1980 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes 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 - Salinity
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
NECI Insufficient data to calculate trend 62231 3 2023 - 2025 29.80 - - - -
NEHM Insufficient data to calculate trend 113173 4 2022 - 2025 14.40 - - - -
NEKD Significantly increasing trend 118328 8 2004 - 2011 33.20 0.31 30.29 0.52 0.0006
NELC No significant trend 100339 7 2005 - 2011 27.90 0.09 25.3 0.53 0.4397
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 12.40 - - - -
NCB19020038 No significant trend 34438 5 2015 - 2019 31.75 -0.06 31.07 -0.11 1
NCBARD16 Insufficient data to calculate trend 7418 2 2015 - 2016 30.07 - - - -
NCBNRCM No significant trend 35411 5 2015 - 2019 30.29 -0.12 30.26 -0.39 0.5483

At one program location, monthly average salinity increased by 0.52 ppt per year. No detectable change in monthly average salinity was observed at three locations. There was insufficient data to fit a model for four locations.

Map showing location of salinity continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Temperature - Continuous

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 - Water Temperature
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
02231291 Insufficient data to calculate trend 710 3 2014 - 2016 23.50 - - - -
NECI Insufficient data to calculate trend 62594 3 2023 - 2025 23.10 - - - -
NEHM Insufficient data to calculate trend 118362 4 2022 - 2025 24.60 - - - -
NEKD No significant trend 118328 8 2004 - 2011 22.10 -0.04 21.88 -0.01 0.8057
NELC No significant trend 100343 7 2005 - 2011 22.70 0.05 22.26 0.04 0.7405
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 22.00 - - - -
NCB19020038 No significant trend 34483 5 2015 - 2019 24.78 -0.03 23.32 -0.01 1
NCBARD16 Insufficient data to calculate trend 7419 2 2015 - 2016 25.08 - - - -
NCBNRCM No significant trend 35817 5 2015 - 2019 24.03 0.07 23.26 0.05 0.6681

No detectable change in monthly average water temperature was observed at four locations. There was insufficient data to fit a model for five locations.

Map showing location of water temperature continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Temperature - Discrete

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 Results for - Water Temperature
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly increasing trend 22846 30 1995 - 2025 23 0.11651 22.17189 0.03225 0.0041

Monthly average water temperature increased by 0.03°C per year.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes 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 - pH
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
NECI Insufficient data to calculate trend 60282 3 2023 - 2025 7.70 - - - -
NEHM Insufficient data to calculate trend 116425 4 2022 - 2025 7.10 - - - -
NEKD Significantly increasing trend 113471 8 2004 - 2011 7.90 0.19 7.87 0.01 0.0491
NELC No significant trend 96488 7 2005 - 2011 7.50 0.02 7.51 0 0.9121
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 7.10 - - - -
NCB19020038 No significant trend 34405 5 2015 - 2019 7.88 -0.01 7.85 0 1
NCBARD16 Insufficient data to calculate trend 6952 2 2015 - 2016 7.66 - - - -
NCBNRCM No significant trend 35819 5 2015 - 2019 7.72 -0.01 7.69 0 0.9317

At one program location, monthly average pH increased by 0.01 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 four locations.

Map showing location of ph continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

pH - Discrete

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 Results for - pH
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly decreasing trend 22611 30 1995 - 2025 7.6 -0.14003 7.74135 -0.00492 0.0005

Monthly average pH decreased by less than 0.01 pH units per year.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Specific Conductivity - Continuous

Seasonal Kendall-Tau Results - Specific Conductivity
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
02231291 Insufficient data to calculate trend 682 3 2014 - 2016 30.40 - - - -
NECI Insufficient data to calculate trend 62231 3 2023 - 2025 45.94 - - - -
NEHM Insufficient data to calculate trend 111827 4 2022 - 2025 23.57 - - - -
NEKD Significantly increasing trend 118327 8 2004 - 2011 50.62 0.31 46.46 0.71 0.0006
NELC No significant trend 100339 7 2005 - 2011 43.33 0.08 39.43 0.77 0.5078
NENR Insufficient data to calculate trend 31438 3 2009 - 2011 20.04 - - - -
Map showing location of specific conductivity continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.
Map showing location of specific conductivity continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Water Clarity

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 - Turbidity
Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
NECI Insufficient data to calculate trend 60677 3 2023 - 2025 15.00 - - - -
NEHM Insufficient data to calculate trend 108736 4 2022 - 2025 12.00 - - - -
NEKD No significant trend 114181 8 2004 - 2011 4.00 0.02 6.06 0.05 0.8697
NELC No significant trend 96153 7 2005 - 2011 15.00 0.16 15.18 0.64 0.1513
NENR Insufficient data to calculate trend 31087 3 2009 - 2011 21.00 - - - -
NCB19020038 No significant trend 31407 5 2015 - 2019 5.77 -0.01 6.79 0.12 0.7876
NCBARD16 Insufficient data to calculate trend 7385 2 2015 - 2016 12.89 - - - -
NCBNRCM No significant trend 34696 5 2015 - 2019 8.64 -0.1 10.09 -0.14 0.6001

No detectable change in monthly average turbidity was observed at four locations. There was insufficient data to fit a model for four locations.

Map showing location of turbidity continuous water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Turbidity - Discrete

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 Results for - Turbidity
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Significantly increasing trend 1098 27 1997 - 2025 7.10751 0.18191 4.20404 0.13605 0.0001

Monthly average turbidity increased by 0.14 NTU per year, indicating a decrease in water clarity.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Total Suspended Solids - Discrete

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 Results for - Total Suspended Solids
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 929 26 1997 - 2025 18 0.05882 17.38333 0.13636 0.2165

Total suspended solids showed no detectable trend between 1997 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Chlorophyll a, Uncorrected for Pheophytin - Discrete

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 Results for - Chlorophyll a, Uncorrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 382 14 2004 - 2025 6.8 -0.10334 9.16876 -0.05231 0.6373

Chlorophyll a, uncorrected for pheophytin, showed no detectable trend between 2004 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Chlorophyll a, Corrected for Pheophytin - Discrete

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 Results for - Chlorophyll a, Corrected for Pheophytin
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No significant trend 722 19 2001 - 2025 5.7 0.10558 4.53264 0.07828 0.1155

Chlorophyll a, corrected for pheophytin, showed no detectable trend between 2001 and 2025.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Secchi Depth - Discrete

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 Results for - Secchi Depth
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Significantly increasing trend 20403 26 2000 - 2025 -0.7 0.09425 -0.78956 0.00271 0.0281

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

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Colored Dissolved Organic Matter - Discrete

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 Results for - Colored Dissolved Organic Matter
Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Insufficient data to calculate trend 551 6 2020 - 2025 26.27063 - - - -

There was insufficient data to fit a model for colored dissolved organic matter.

Map showing location of discrete water quality sampling locations within the boundaries of Nassau River-St. Johns River Marshes 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 Nassau River-St. Johns River Marshes Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.