Historical News
Water Column Profiles
Surface salinities among the sites surveyed ranged from 21 psu at Pomham Rocks to 27 psu at Edgewood Yacht Club. Bottom salinities measured approximately 30 psu at all sites. Surface water temperatures ranged from 3°C at Conimicut Point to 3.5°C at the remaining sites. Bottom temperatures ranged from 3°C at most sites to 4°C at Edgewood Yacht Club.
Dissolved oxygen (DO) ranged from a minimum of approximately 11 mg/L in bottom waters at all sites to 12.1 mg/L in surface waters at Conimicut Point. Hypoxic conditions (e.g., DO concentrations <2.9 mg/L) were not observed at any of the sites. Please note that due to a quality control issue, numerical fluorescence data are not posted at this time.
Water Column Clarity
Water clarity was measured at four locations in the Providence River on February 24, 2021; the survey day was cut short due to mechanical problems on the boat. Moderate rainfall totaling 0.81 inches was recorded in the area over the five days prior to the survey, and snowmelt also occurred over that time. Overall, Secchi depth averaged 4.04 meters, compared to 3.13 meters on January 13, 2021. The lowest clarity (3.63 meters) was measured at Bullock Reach, while the greatest clarity (4.25 meters) was measured at Pomham Rocks. Generally, water clarity was higher at the northernmost sites (Pomham Rocks and Edgewood Yacht Club) than the southern sites (Bullock Reach and Conimicut Point) this week.
Water Column Profiles
R/V Monitor's Blog
On Wednesday, March 31st, the crew of the R/V Monitor was out on the upper Bay collecting bacteria samples, taking Secchi Disk and Par sensor 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. The crew conducted side by side profile tests using the new YSI EXO2 sonde and the YSI 6 Series sonde. Sara captained the boat while monitoring professionals Daryll, Justin, and Rebecca collected the samples and data. It was a cloudy day with a southwest wind and a slight chop on the water. The photo taken this day was of the Conimicut lighthouse.
Surface Mapping
Data were collected on March 31, 2021 while the R/V Monitor was underway collecting bacteria samples in the Seekonk and Providence River estuaries. The chlorophyll concentrations ranged from good to fair in a north to south gradient in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Seekonk River (5.07 µg/L), Upper Providence River (5.53 µg/L), Edgewood Shoals area (7.83 µg/L), Pawtuxet River area (9.55 µg/L), and Lower Providence River (11.83 µg/L). Overall, chlorophyll ranged between 1.80 µg/L and 20.60 µg/L with an overall average of 7.16 µg/L. The chlorophyll data from this date are presented in the map below: