Historical News
Surface Mapping
Data was collected on May 9, 2018 while the R/V Monitor was underway collecting bacteria samples and performing vertical profiles in the Providence and Seekonk River estuaries. The chlorophyll concentrations were good to fair in areas surveyed with evidence of a north-south gradient. From north to south, average chlorophyll concentrations were as follows: Seekonk River (3.32 µg/l), Upper Providence River (6.04 µg/l), Edgewood Shoals area (17.98 µg/l), Pawtuxet River area (11.23 µg/l), and the Lower Providence River (16.05 µg/l). Overall, chlorophyll ranged between 0.50 µg/l and 28.30 µg/l with an overall average of 10.76 µg/l. The chlorophyll data from this date is presented in the map below:
R/V Monitor's Blog
On Wednesday, May 9th, 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, 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 Jeff and Mike collected the samples and data. The day started off very foggy with no wind. By late morning the fog began to lift, the wind picked-up and the water became slightly choppy. The photo shown below was taken in Pawtuxet Cove.
Water Column Profiles
Water column profiles were measured at three sites in the Providence and Seekonk Rivers on April 25. Conditions were quite windy and wavy and were not suitable for sampling at all sites. Approximately 1.48 inches of rain fell throughout the day on the day of sampling. Some stratification was noted with higher salinities at depth in comparison to the surface; temperatures were quite uniform throughout the water column at all sites. Surface temperatures were 11.20C at Bullock Reach, 11.70C at Pawtuxet Cove, and 10.70C at India Point; temperatures at depth were 6.90C at Bullock Reach and India Point, and 10.80C at Pawtuxet Cove. Surface salinities measured were 18.7 PSU at Bullock Reach, 2.6 PSU at Pawtuxet Cove, and 12.7 PSU at India Point. Salinity at depth ranged from 28.8 PSU at Bullock Reach, 14.9 PSU at Pawtuxet Cove, and 27.6 PSU at India Point. Oxygen levels were very high this week and no hypoxic readings were measured. Minimum dissolved oxygen concentrations recorded were 10.1 mg/L at Bullock Reach, 7.6 mg/L at Pawtuxet Cove, and 9.6 mg/L at India Point. The maximum fluorescence, 11.4 mg/m3, was found at a depth of 2.5 meters at Bullock Reach.
Water Column Profiles
Water column profiles were measured at six sites in the Providence and Seekonk Rivers on April 18. There was approximately 2.0 inches of rainfall during the three days prior to sampling. The water column was partially stratified across some locations. This stratification was reflected with higher salinities at depth in comparison to the surface; temperatures were quite uniform throughout the water column at all sites. Surface temperatures ranged from 6.6°C at Conimicut Point to 8.4oC at Pawtuxet Cove. Temperatures at depth ranged from 5.8°C at Conimicut Point and Pomham Rocks to 7.2°C at Pawtuxet Cove. Surface salinity ranged from 4.2 PSU at Pawtuxet Cove to 23.9 PSU at Edgewood Yacht Club. Salinity at depth ranged from 23.6 PSU at Pawtuxet Cove to 29.6 PSU at Conimicut Point. Oxygen levels were very high this week and no hypoxic readings were measured. Minimum dissolved oxygen concentrations ranged from 8.8 mg/L to 10.2 mg/L. The maximum fluorescence, 11.0 mg/m3, was found at a depth of 4.25 meters at Edgewood Yacht Club.
Fixed Site Network
Phillipsdale
This week at Phillipsdale, data revealed good water quality. Over the course of the week there was approximately 2.26 inches of rainfall and an increase in flow from the Blackstone River. This increase in freshwater input is reflected in surface salinities as they were quite low and remained below 4.0 psu for most of the week. Overall, surface salinity averaged 2.5 psu with a minimum of 0.6 psu, and a maximum of 5.7 psu. Bottom salinity fluctuated with the tides over the course of the week with an average of 11.0 psu and a range of 0.9 psu – 27.0 psu. Surface and bottom temperatures increased by approximately 2-4oC as compared to last week with surface temperatures averaging 12.6oC with a range of 9.6oC – 16.8oC and bottom temperatures averaging 10.8oC and ranged between 6.6oC – 15.8oC. Surface chlorophyll was relatively low though did increase over the week with a weekly average of 4.1 ug/L, with a daily average peak of about 5.0 ug/L. Dissolved oxygen (DO) for the week was very good at both the surface and the bottom though slightly decreased from pervious weeks; surface DO had an average of 10.8 mg/L and a range of 9.8 mg/L – 12.1 mg/L. Dissolved oxygen in the bottom waters had a weekly average of 10.0 mg/l and ranged from a minimum of 8.6 mg/L to a maximum of 11.8 mg/L. Note that tidal fluctuations and Blackstone River flow greatly influence bottom DO, temperature and salinity at this location.
Bullocks Reach
The sondes at Bullocks Reach were removed for the season in November 2017. Staff is currently testing and preparing new equipment for deployment. It is anticipated that the station will be operational again for the season in May/June 2018.
