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.
Table:

Total nitrogen showed no detectable trend between 1996 and 2026.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No detectable trend 1545 31 1996 - 2026 0.36 0.02489 0.36348 0.00009 0.8414
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

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

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Increasing trend 1542 31 1996 - 2026 0.015 0.10625 0.01506 0.00008 0.0349
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

At one program location, monthly average dissolved oxygen decreased by 0.04 mg/L per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Decreasing trend 243248 9 2018 - 2026 7.4 -0.2 7.44 -0.04 0.03
Map showing location of dissolved oxygen continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Monthly average dissolved oxygen decreased by 0.03 mg/L per year.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Decreasing trend 8740 33 1991 - 2026 7.275 -0.1597 7.96651 -0.02991 0
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

At one program location, monthly average dissolved oxygen saturation decreased by 0.47% per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Decreasing trend 241140 9 2018 - 2026 98.4 -0.21 103.19 -0.47 0.02
Map showing location of dissolved oxygen saturation continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

There was insufficient data to fit a model 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 Insufficient data 462 6 2019 - 2025 86.5 - - - -
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Monthly average salinity increased by 0.15 ppt per year.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
All Increasing trend 9681 35 1980 - 2026 18.4 0.26806 14.75431 0.15428 0
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

At one program location, monthly average salinity increased by 0.55 ppt per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Increasing trend 251661 9 2018 - 2026 25.4 0.36 23.55 0.55 0
Map showing location of salinity continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

No detectable change in monthly average water temperature was observed at one location.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH No detectable trend 253721 9 2018 - 2026 24.7 0.04 25.02 0.05 0.71
Map showing location of water temperature continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

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

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Increasing trend 9166 34 1980 - 2026 22.7 0.12239 21.83555 0.03218 0.0017
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

At one program location, monthly average pH decreased by 0.01 pH units per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Decreasing trend 245245 9 2018 - 2026 8.2 -0.16 8.25 -0.01 0.05
Map showing location of ph continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

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

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field Decreasing trend 4826 33 1991 - 2026 8.06 -0.14736 8.0915 -0.00426 0.0002
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.

Specific Conductivity - Continuous

Scatter plot of monthly average specific conductivity 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 specific conductivity 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.
Table:

At one program location, monthly average specific conductivity increased by 0.79 mS/cm per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Increasing trend 249935 9 2018 - 2026 39.91 0.35 37.35 0.79 0
Map showing location of specific conductivity continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

At one program location, monthly average turbidity increased by 0.11 NTU per year.

Program Location Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
BBSCH Increasing trend 219010 9 2018 - 2026 1 0.25 1.24 0.11 0
Map showing location of turbidity continuous water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Monthly average turbidity increased by 0.02 NTU per year, indicating a decrease in water clarity.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Increasing trend 3158 31 1995 - 2025 1.1 0.11311 1.26251 0.01502 0.0121
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Total suspended solids showed no detectable trend between 2005 and 2025.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No detectable trend 330 21 2005 - 2025 4.64 0.00139 4.84802 -0.02 0.7079
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Chlorophyll a, uncorrected for pheophytin, showed no detectable trend between 2000 and 2026.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab No detectable trend 619 19 2000 - 2026 2 0.1297 2.43238 0.03131 0.0976
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Monthly average chlorophyll a, corrected for pheophytin, increased by 0.08 µg/L per year, indicating a decrease in water clarity.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Increasing trend 652 15 2012 - 2026 1.855 0.28702 1.54162 0.07607 0
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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).
Table:

Secchi depth showed no detectable trend between 1991 and 2026.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Field No detectable trend 1042 23 1991 - 2026 -0.9 0.00693 -0.95538 0.00033 0.8897
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh 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.
Table:

Monthly average colored dissolved organic matter increased by 0.1 PCU per year, indicating a decrease in water clarity.

Activity Type Statistical Trend Sample Count Years with Data Period of Record Median Result Value Tau Sen Intercept Sen Slope P
Lab Increasing trend 1220 27 1999 - 2026 13 0.14855 13.36714 0.1034 0.0042
Map showing location of discrete water quality sampling locations within the boundaries of St. Martins Marsh 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 St. Martins Marsh Aquatic Preserve. The bubble size on the maps above reflect the amount of data available at each sampling site.