Week of January 8 - 14, 2023
R/V Monitor's Blog
On Tuesday, January 10th, the crew of the R/V Monitor
was out on the upper Bay for the first time this year collecting nutrients and plankton samples, taking
Secchi Disk water clarity measurements, and conducting real-time surface mapping
of water quality parameters, including dissolved oxygen, chlorophyll, water
temperature, salinity, and pH, all in an effort to document water quality
improvements associated with NBC construction projects. Jeffrey captained the boat
while monitoring professionals Jeff, and Tyler collected the samples and
data. It was a cloudy and cool day with a calm wind out of the northwest. The water was calm all day. The featured photo shows the Conimicut Point lighthouse.
Week of November 27 - December 3, 2022
Water Column Clarity
Water clarity was measured at six locations in the Providence River estuary on November 29. Rainfall totaling 0.54 inches was recorded at TF Green in the five days prior to the survey, the majority of which fell on November 27. Secchi depth averaged 4.2 meters, compared to 3.1 meters on the previous survey (November 23). The lowest clarity this week (3.77 meters) was measured at Pawtuxet Cove, while the greatest clarity (4.5 meters) was measured at India Point Park. There was a general north-to-south gradient of decreasing water clarity among the sites this week.
Week of September 25-October 1, 2022
Water Column Profiles
Water column profiles were conducted at eight locations in the Providence and Seekonk Rivers using a Seabird instrument on September 28, 2022. In the three days leading up to the sampling event, 0.30 inches of rainfall was recorded at T.F. Green. Evidence of density stratification was observed at most sites this week, with Point Street Bridge and Phillipsdale Landing showing signs of being strongly stratified.
Surface salinities among all sites ranged from 28 psu at Bullock Reach Buoy and Conimicut Point West down to 16 psu at Phillipsdale Landing. Bottom salinities ranged from 30 psu at Conimicut Point down to 25 psu at Phillipsdale Landing. The warmest surface water temperature (22°C) was observed at Point St. Bridge, while the warmest bottom temperature (20°C) was observed at most of the sites. The coolest water temperatures ranged from 18°C at the surface of Bullock Reach Buoy to 19.0°C at bottom of Conimicut Point.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at all sites this week; the lowest DO observed was approximately 4.1 mg/L in the bottom waters at Point St. Bridge. Overall, fluorescence decreased from the previous week, with the highest values (4.23 mg/m3) observed at the surface (<1.00 m) at Edgewood Yacht Club. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled.
Week of September 18-24, 2022
Water Column Profiles
Water column profiles were conducted at eight locations in the Providence and Seekonk Rivers using a Seabird instrument on September 21, 2022. In the three days leading up to the sampling event, 0.08 inches of rainfall was recorded at T.F. Green. Evidence of density stratification was observed at most sites, while the water column at Pomham Rocks, Edgewood Yacht Club, and Edgewood Shoal was more well-mixed.
Surface salinities among all sites ranged from 29 psu at Pomham Rocks down to 16 psu at Phillipsdale Landing. Bottom salinities ranged from 31.5 psu at Conimicut Point down to 27.5 psu at Phillipsdale. The warmest surface water temperature (22.4°C) was observed at India Point Park, while the warmest bottom temperature (22.2°C) was observed at Pawtuxet Cove and Phillipsdale Landing. The coolest water temperatures ranged from 21.4°C at the surface of Conimicut Point West and Phillipsdale Landing to 21.1°C at bottom of Conimicut Point.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at most sites except for three sites dropping into hypoxic conditions in the middle to bottom waters: Edgewood Yacht Club (minimum of 2.54 mg/L), Edgewood Shoal (minimum of 1.64 mg/L), and Phillipsdale Landing (minimum 2.09 mg/L). Overall, fluorescence increased from the previous week, with the highest values (39.97 mg/m3) observed near the surface (~1.25 m) at Phillipsdale Landing. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled.
Week of September 11-17, 2022
Water Column Profiles
Water column profiles were conducted at eight locations in the Providence and Seekonk Rivers using a Seabird instrument on September 14, 2022. In the three days leading up to the sampling event, 0.68 inches of rainfall was recorded at T.F. Green. Evidence of moderate to weak density stratification was observed at all of the sites this week.
Surface salinities among all sites ranged from 28 psu at Bullock Reach Buoy and Conimicut Point down to 20 psu at Phillipsdale Landing. Bottom salinities ranged from 31 psu at Conimicut Point down to 25 psu at Phillipsdale Landing. Point St. Bridge had the warmest surface and bottom temperatures, 24.6°C and 23.9°C respectively. The coolest water temperatures ranged from 22.4°C at the surface of Bullock Reach Buoy and Conimicut Point West to 22.2°C at bottom of Conimicut Point.
Dissolved oxygen (DO) conditions remained above the hypoxia threshold (2.9 mg/L) at most sites except for three sites dropping below the limit in the middle to bottom waters, with Phillipsdale Landing with a minimum of 2.41 mg/L, and India Point Park with a minimum of 2.98 mg/L. The third site with hypoxic conditions has low DO in the bin-averaged data at the bottom of Pomham Rocks, which is believed to be an artifact of the bin-averaging data calculations or due to sediment interference. Overall, fluorescence increased slightly from the previous week, with the highest values (4.70 mg/m3) observed near the surface (~1.00 m) at Pawtuxet Cove. Please note numerical fluorescence data were not posted from 2020 to 2021 due to a QC issue. This issue has been resolved and fluorescence data from 2020 and 2021 will be backfilled.
