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.
Seasonal Kendall-Tau Results - Dissolved Oxygen
| gtmpiwq |
No significant trend |
699401 |
26 |
2001 - 2026 |
5.9 |
-0.06 |
5.78 |
0.00 |
0.1298 |
| gtmfmwq |
Significantly increasing trend |
718097 |
26 |
2001 - 2026 |
6.5 |
0.10 |
6.25 |
0.00 |
0.0153 |
| gtmsswq |
Significantly increasing trend |
699026 |
25 |
2002 - 2026 |
6.3 |
0.10 |
5.92 |
0.01 |
0.0206 |
| gtmpcwq |
No significant trend |
736088 |
26 |
2001 - 2026 |
5.5 |
0.05 |
5.26 |
0.01 |
0.1932 |
At two program locations, monthly average dissolved oxygen increased by
less than 0.01 mg/L per year at one site and by 0.01 mg/L per year at
the other. No detectable change in monthly average dissolved oxygen was
observed at two locations.
Map showing location of dissolved oxygen
continuous water quality sampling locations within the boundaries of
Guana Tolomato Matanzas National Estuarine Research Reserve.
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.
Seasonal Kendall-Tau Results for - Dissolved Oxygen
| Field |
Significantly decreasing trend |
21643 |
31 |
1995 - 2025 |
5.97 |
-0.16437 |
6.16464 |
-0.02524 |
0 |
Monthly average dissolved oxygen decreased by 0.03 mg/L per year.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results - Dissolved Oxygen
Saturation
| gtmpiwq |
Significantly decreasing trend |
705219 |
26 |
2001 - 2026 |
82.2 |
-0.15 |
81.97 |
-0.14 |
0.0003 |
| gtmfmwq |
Significantly increasing trend |
731140 |
26 |
2001 - 2026 |
92.7 |
0.16 |
89.66 |
0.09 |
0.0001 |
| gtmsswq |
Significantly increasing trend |
704965 |
25 |
2002 - 2026 |
89.5 |
0.16 |
84.21 |
0.11 |
0.0002 |
| gtmpcwq |
No significant trend |
737581 |
26 |
2001 - 2026 |
71.5 |
0.03 |
68.01 |
0.04 |
0.4939 |
At two program locations, monthly average dissolved oxygen saturation
increased by 0.09% per year at one site and by 0.11% per year at the
other. At one program location, monthly average dissolved oxygen
saturation decreased by 0.14% per year. No detectable change in monthly
average dissolved oxygen saturation was observed at one location.
Map showing location of dissolved oxygen
saturation continuous water quality sampling locations within the
boundaries of Guana Tolomato Matanzas National Estuarine Research
Reserve. 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.
Seasonal Kendall-Tau Results for - Dissolved Oxygen
Saturation
| Field |
Significantly increasing trend |
2522 |
24 |
1999 - 2025 |
81.7 |
0.11881 |
79.00647 |
0.26134 |
0.0151 |
Monthly average dissolved oxygen saturation increased by 0.26% per year.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Salinity
| All |
Significantly decreasing trend |
26181 |
32 |
1980 - 2025 |
31.7 |
-0.36753 |
37.22153 |
-0.31767 |
0 |
Monthly average salinity decreased by 0.32 ppt per year.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results - Salinity
| gtmpiwq |
Significantly decreasing trend |
703518 |
26 |
2001 - 2026 |
27.70 |
-0.26 |
32.16 |
-0.3 |
0 |
| 872-0494 |
Insufficient data to calculate trend |
34918 |
2 |
2020 - 2021 |
8.99 |
- |
- |
- |
- |
| gtmfmwq |
Significantly decreasing trend |
705987 |
26 |
2001 - 2026 |
34.40 |
-0.16 |
34.84 |
-0.05 |
0.0001 |
| gtmsswq |
Significantly decreasing trend |
683666 |
25 |
2002 - 2026 |
33.90 |
-0.12 |
34.22 |
-0.05 |
0.004 |
| gtmpcwq |
Significantly decreasing trend |
745868 |
26 |
2001 - 2026 |
16.60 |
-0.12 |
16.31 |
-0.19 |
0.0027 |
At four program locations, monthly average salinity decreased between
0.05 and 0.3 ppt per year. There was insufficient data to fit a model
for one location.
Map showing location of salinity continuous
water quality sampling locations within the boundaries of Guana
Tolomato Matanzas National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results - Water Temperature
| gtmpiwq |
Significantly increasing trend |
753811 |
26 |
2001 - 2026 |
24.20 |
0.18 |
23.6 |
0.04 |
0 |
| 872-0494 |
Insufficient data to calculate trend |
35473 |
2 |
2020 - 2021 |
22.34 |
- |
- |
- |
- |
| gtmfmwq |
Significantly increasing trend |
751023 |
26 |
2001 - 2026 |
23.70 |
0.21 |
22.99 |
0.04 |
0 |
| gtmsswq |
Significantly increasing trend |
717305 |
25 |
2002 - 2026 |
23.80 |
0.22 |
22.94 |
0.05 |
0 |
| gtmpcwq |
Significantly increasing trend |
754434 |
26 |
2001 - 2026 |
24.30 |
0.15 |
23.64 |
0.04 |
0.0002 |
At four program locations, monthly average water temperature increased
between 0.04 and 0.05°C per year. There was insufficient data to fit a
model for one location.
Map showing location of water temperature
continuous water quality sampling locations within the boundaries of
Guana Tolomato Matanzas National Estuarine Research Reserve.
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.
Seasonal Kendall-Tau Results for - Water Temperature
| Field |
Significantly increasing trend |
24524 |
31 |
1995 - 2025 |
23.3 |
0.24139 |
22.19334 |
0.05734 |
0 |
Monthly average water temperature increased by 0.06°C per year.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results - pH
| gtmpiwq |
Significantly decreasing trend |
696449 |
26 |
2001 - 2026 |
7.6 |
-0.17 |
7.61 |
0 |
0 |
| gtmfmwq |
Significantly decreasing trend |
702168 |
26 |
2001 - 2026 |
8.0 |
-0.14 |
7.98 |
0 |
0.0006 |
| gtmsswq |
No significant trend |
674734 |
25 |
2002 - 2026 |
7.9 |
0.01 |
7.86 |
0 |
0.8494 |
| gtmpcwq |
No significant trend |
730315 |
26 |
2001 - 2026 |
7.4 |
-0.08 |
7.44 |
0 |
0.0568 |
At two program locations, monthly average pH decreased by 0.00 pH units
per year. No detectable change in monthly average pH was observed at two
locations.
Map showing location of ph continuous water
quality sampling locations within the boundaries of Guana Tolomato
Matanzas National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - pH
| Field |
Significantly decreasing trend |
17952 |
31 |
1995 - 2025 |
7.8 |
-0.37495 |
7.86792 |
-0.01362 |
0 |
Monthly average pH decreased by 0.01 pH units per year.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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
| gtmpiwq |
Significantly decreasing trend |
703518 |
26 |
2001 - 2026 |
43.06 |
-0.27 |
49.24 |
-0.42 |
0 |
| 872-0494 |
Insufficient data to calculate trend |
34894 |
2 |
2020 - 2021 |
14.10 |
- |
- |
- |
- |
| gtmfmwq |
Significantly decreasing trend |
705986 |
26 |
2001 - 2026 |
52.22 |
-0.15 |
52.81 |
-0.07 |
0.0002 |
| gtmsswq |
Significantly decreasing trend |
683665 |
25 |
2002 - 2026 |
51.54 |
-0.12 |
51.95 |
-0.07 |
0.0038 |
| gtmpcwq |
Significantly decreasing trend |
746635 |
26 |
2001 - 2026 |
27.04 |
-0.13 |
27.25 |
-0.3 |
0.002 |
Map showing location of specific conductivity
continuous water quality sampling locations within the boundaries of
Guana Tolomato Matanzas National Estuarine Research Reserve.
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.
Seasonal Kendall-Tau Results - Turbidity
| gtmpiwq |
Significantly decreasing trend |
679520 |
26 |
2001 - 2026 |
10 |
-0.12 |
14.61 |
-0.08 |
0.0048 |
| gtmfmwq |
Significantly decreasing trend |
717246 |
26 |
2001 - 2026 |
7 |
-0.14 |
9.08 |
-0.07 |
0.001 |
| gtmsswq |
No significant trend |
670272 |
25 |
2002 - 2026 |
9 |
-0.04 |
10.11 |
-0.02 |
0.3797 |
| gtmpcwq |
Significantly decreasing trend |
721298 |
26 |
2001 - 2026 |
9 |
-0.17 |
9.80 |
-0.10 |
0 |
At three program locations, monthly average turbidity decreased between
0.07 and 0.1 NTU per year. No detectable change in monthly average
turbidity was observed at one location.
Map showing location of turbidity continuous
water quality sampling locations within the boundaries of Guana
Tolomato Matanzas National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Turbidity
| Lab |
Significantly increasing trend |
14885 |
31 |
1995 - 2025 |
4.5 |
0.26559 |
4.57195 |
0.09917 |
0 |
Monthly average turbidity increased by 0.1 NTU per year, indicating a
decrease in water clarity.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Total Suspended
Solids
| Lab |
Significantly decreasing trend |
5276 |
29 |
1997 - 2025 |
17 |
-0.38129 |
28.90548 |
-0.6179 |
0 |
Monthly average total suspended solids decreased by 0.62 mg/L per year,
indicating an increase in water clarity.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Chlorophyll a, Uncorrected
for Pheophytin
| Lab |
Significantly increasing trend |
3970 |
18 |
2006 - 2025 |
6.3 |
0.28882 |
3.83917 |
0.33361 |
0 |
Monthly average chlorophyll a, uncorrected for pheophytin, increased by
0.33 µg/L per year, indicating a decrease in water clarity.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Chlorophyll a, Corrected for
Pheophytin
| Lab |
Significantly increasing trend |
4349 |
22 |
2002 - 2025 |
4.7 |
0.43916 |
1.33651 |
0.34993 |
0 |
Monthly average chlorophyll a, corrected for pheophytin, increased by
0.35 µg/L per year, indicating a decrease in water clarity.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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).
Seasonal Kendall-Tau Results for - Secchi Depth
| Field |
No significant trend |
3007 |
26 |
1999 - 2025 |
-0.8 |
0.06632 |
-0.84475 |
0.00234 |
0.1743 |
Secchi depth showed no detectable trend between 1999 and 2025.
Map showing location of discrete water quality
sampling locations within the boundaries of Guana Tolomato Matanzas
National Estuarine Research Reserve. 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.
Seasonal Kendall-Tau Results for - Colored Dissolved Organic
Matter
| Lab |
Insufficient data to calculate trend |
643 |
9 |
2009 - 2025 |
16 |
- |
- |
- |
- |
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 Guana Tolomato Matanzas
National Estuarine Research Reserve. The bubble size on the maps
above reflect the amount of data available at each sampling site.