Week of August 7 - 13, 2022
Water Column Profiles
Water column profiles were conducted at six locations in the Providence River estuary using a Seabird profiling instrument on August 9, 2022. The weather leading up to the survey was dry, with no rainfall recorded at T.F. Green over the three days prior to the survey. The water column was well-mixed at most sites.
Surface salinity this week ranged from 26 psu at India Point Park to 30 psu at Conimicut Point. Bottom salinity ranged from 27 psu at India Point Park and Edgewood Yacht Club to 30 psu at Conimicut Point, Bullock Reach, and Pomham Rocks. The coolest surface waters were at Conimicut Point, measuring 26.9°C; the warmest surface waters were at Edgewood Yacht Club, measuring 28.2°C. Bottom waters ranged from approximately 25.6°C at Pomham Rocks to 27.7°C at Pawtuxet Cove and Edgewood Yacht Club.
Dissolved oxygen (DO) was moderate to low at most sites this week, with two sites exhibiting hypoxic conditions (DO <2.9 mg/L) in the bottom waters. India Point Park waters had minimum readings around 2.5 mg/L; Pomham Rocks minimum readings were 2.6 mg/L. Fluorescence increased slightly since the previous week, with the highest values (23.3 mg/m3) observed near the bottom (~2 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 back-filled.
Week of September 18 - 24, 2022
R/V Monitor's Blog
On Wednesday, September 21st, the crew of the R/V Monitor
was out on the upper Bay collecting nutrients and plankton samples, taking
Secchi Disk and Par sensor water clarity measurements, conducting water column
profiles using the Seabird instrument, 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. Sara captained the boat
while monitoring professionals Fern, Jeff and Mike collected the samples and
data. It was mostly cloudy with some sun occasionally shining through the clouds. The water was calm in the morning turning slightly
choppy by the afternoon as a west wind picked up. The featured photo shows a cargo ship by ProvPort.
Week of September 18 – September 24, 2022
Data were collected on September 21, 2022, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuaries. The average chlorophyll concentrations were poor in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Seekonk River (62.02 µg/L), Upper Providence River (35.50 µg/L), Edgewood Shoals area (16.36 µg/L), Pawtuxet River area (12.09 µg/L), and Lower Providence River (14.96 µg/L). Overall, chlorophyll ranged between 3.41 and 84.15 µg/L with an overall average of 27.57 µg/L. The chlorophyll data from this date are presented in the map below:
Week of July 31 - August 6, 2022
Water Column Profiles
Water column profiles were conducted at eight locations in the Providence and Seekonk River estuaries using a Seabird profiling instrument on August 3, 2022. Light rainfall of 0.11 inches was recorded at T.F. Green two days prior to the survey. Evidence of density stratification was observed at most sites, while the water column at Point St. Bridge and Pomham Rocks was more well-mixed.
Salinity was lowest this week at Phillipsdale Landing, averaging approximately 24 psu at the surface and 26 psu at the bottom. Salinity was highest at Bullock Reach Buoy and Conimicut Point, averaging 29 psu at the surface and 31 psu at the bottom. These two sites had the coldest waters, averaging 25°C at the surface and 22-23°C at the bottom. The warmest water temperatures (29-30°C) were observed at Point St. Bridge.
Overall, dissolved oxygen (DO) was low in the bottom waters at most sites this week, with three sites exhibiting hypoxic conditions (DO <2.9 mg/L) below 4 m depth. India Point Park waters had minimum readings around 1.0 mg/L; Phillipsdale Landing minimum readings were 2.1 mg/L; Edgewood Yacht Club minimum readings were 2.8 mg/L. Fluorescence was similar to the previous week, with the highest values (16.7 mg/m3) observed near the surface (~0.75 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 back-filled.
Week of September 4 - 10, 2022
Phytoplankton samples were collected on September 7, 2022 at Bullock Reach and analyzed in the laboratory shortly after collection. It was cloudy on Narragansett Bay with choppy waters and strong northeast winds. Sondes data revealed the surface water temperature was 22.17⁰C, salinity was 20.43 psu, and chlorophyll a was 0.39 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a medium brown color and had a medium filter time. The tow net sample was analyzed qualitatively for microorganisms using phase contrast microscopy. The whole water sample was analyzed quantitatively under 200x phase contrast microscopy. A Hensen Stempel pipette was used to accurately deliver 1ml of sample to a Sedge-wick Rafter chamber. This analysis revealed a total of 858,000 cells per Liter. The microflagellates were found at 814,000 cells/L. The most predominant phytoplankton genus was Chaetoceros spp. at 18,000 cells/L. Other representative genera include Skeletonema spp. and Leptocylindrus spp.
200x phase contrast micrograph of diatom Dictoycha spp.