Surface chlorophyll data were collected on August 7, 2024 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as fair in all areas surveyed. Overall, chlorophyll ranged 1.72 to 24.79 µg/L with an average of 7.32 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries on August 7, 2024 using a Seabird Electronics profiler. In the five days leading up to the survey, 0.95 inches of precipitation were recorded at T.F. Green. Water column stratification at the sites varied from weakly stratified at Pawtuxet Cove and Edgewood Yacht Club, to strongly stratified at Conimicut Point.
Dissolved oxygen (DO) conditions were below the hypoxia threshold (2.9 mg/L) in the lower portion of the water column at Edgewood Yacht Club, in the middle and lower portions of the water column at Pomham Rocks, and in all portions of the water column (upper, middle and lower) at India Point Park and Phillipsdale Landing. The highest fluorescence readings for the week were measured around 2 meters below the surface at Edgewood Yacht Club.
Nutrient samples were collected from seven river stations and seven bay stations on August 7th. All bay stations were sampled at the surface and bottom. In the five days prior to sampling and the morning of, there were 1.02 inches of precipitation recorded at T.F. Green.
Among the river stations sampled, the highest total nitrogen (TN) and dissolved inorganic nitrogen (DIN) concentrations were observed at Blackstone River @ Bike Path Bridge (TN = 1,390 ppb, DIN = 1,160 ppb); the highest total dissolved nitrogen (TDN) was observed in one of the duplicate samples at Pawtuxet River @ Broad St (1,470 ppb). The lowest TN, TDN, and DIN were observed at Woonasquatucket River @ Manton Ave Bridge (TN = 514, TDN = 480 ppb, DIN = 232 ppb).
Among the bay stations sampled, the highest surface total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) were observed at Pawtuxet Cove (TN = 1,190 ppb, TDN = 1,040 ppb, DIN = 790 ppb). The lowest surface TN, TDN, and DIN concentrations were observed at Conimicut Point (TN = 653 ppb, TDN = 403 ppb, DIN = 154 ppb).
The next scheduled sampling date is August 21, 2024.
Surface chlorophyll data were collected on August 1, 2024 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as fair in all areas surveyed. Overall, chlorophyll ranged -0.45 to 63.34 µg/L with an average of 11.02 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Surface chlorophyll data were collected on July 24, 2024 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as fair in all areas surveyed. Overall, chlorophyll ranged 2.16 to 38.37 µg/L with an average of 11.21 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Surface chlorophyll data were collected on July 17, 2024 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as poor in the Seekonk River and as fair in all other areas. Overall, chlorophyll ranged 2.29 to 57.17 µg/L with an average of 18.45 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was fair to poor this week. Weather conditions included sporadic rain events, with 1.16 inches of precipitation recorded at T.F. Green. The Blackstone River flow fluctuate through the week in response to rain, rising above the 19-year daily median mid-way through the week. Surface salinity averaged 17.8 ppt and ranged from 7.7 ppt to 24.4 ppt. At the bottom, salinity averaged 22.6 ppt and ranged from 14.3 ppt to 25.8 ppt. Temperatures continued to increase this week, averaging 25.5°C at the surface and ranging 23.4°C – 27.9°C. At the bottom, temperatures averaged 24.5°C and ranged 22.8°C – 26.8°C.
Dissolved oxygen (DO) at Phillipsdale Landing dropped below the hypoxia threshold (i.e., DO >2.9 mg/L) over the week. Surface DO average 6.5 mg/L and ranged from 0.8 mg/L to 17.3 mg/L. Bottom DO concentrations averaged 2.6 mg/L and ranged from 0.2 mg/L to 9.2 mg/L. The longest period of hypoxic conditions (1 day, 9 hours and 31 minutes) occurred at the bottom depth between the morning of July 29th and the morning of July 30th. During this period, bottom DO averaged around 1.51 mg/L. Chlorophyll readings increased from last week, averaging 33.5 µg/L at the surface and 22.6 µg/L at the bottom. Maximum chlorophyll at the surface reached 347.5 µg/L on the morning of August 4th. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Sondes were swapped this week on the morning of July 30th. Overall, water quality was good at Bullock Reach this week. Salinity averaged 26.5 ppt, 28.3 ppt, and 30.1 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 15.7 – 28.3 ppt, mid salinity ranged 26.6 – 29.7 ppt, and bottom salinity ranged 28.4 – 31.3 ppt. Surface temperature averaged 24.7°C and ranged from 22.5°C to 27.7°C. Mid temperatures averaged 23.9°C and ranged from 21.8°C to 26.7°C. Bottom temperatures averaged 22.5°C and ranged from 20.8°C to 24.7°C.
DO at Bullock Reach remained above the hypoxia threshold (i.e., DO >2.9 mg/L) at the surface and mid depths throughout the week. Bottom DO sporadically dropped below the hypoxia threshold this week. Surface DO averaged 8.2 mg/L and ranged 4.7 – 14.4 mg/L. In the mid waters, DO averaged 5.8 mg/L and ranged 3.0 – 7.8 mg/L. At the bottom, DO averaged 3.7 mg/L and ranged 2.4 – 6.7 mg/L. The longest period of hypoxic conditions (3 hours and 30 minutes) occurred at the bottom depth during July 30th. During this period, bottom DO averaged around 2.76 mg/L. Chlorophyll readings ranged from low to elevated, with evidence of moderate phytoplankton blooms occurring throughout the week. Readings averaged 21.8 µg/L at the surface, 17.5 µg/L at mid-depth, and 4.9 µg/L at the bottom. The maximum surface chlorophyll was 49.7 µg/L on the morning of August 2nd.
Surface chlorophyll data were collected on July 10, 2024 while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as poor in the Seekonk River and Northern Providence River Channel and as good in all other areas. Overall, chlorophyll ranged 0.81 to 82.48 µg/L with an average of 19.85 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Surface chlorophyll data were collected on July 3, 2024 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as poor in the Lower Providence River Area and as fair in all other areas. Overall, chlorophyll ranged from 2.27 to 52.87 µg/L with an average of 16.49 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Surface chlorophyll data were collected on June 17, 2024 while the R/V Monitor was underway collecting bacteria samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were categorized as poor in the Seekonk River and as fair in all other areas. Overall, chlorophyll ranged from 0.0 to 72.05 µg/L with an average of 13.74 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
