Historical News
Surface Mapping
Data was collected on June 27, 2018 while the R/V Monitor was underway collecting nutrient samples and performing vertical profiles in the Providence River estuary. The chlorophyll concentrations were fair in areas surveyed. From north to south, average chlorophyll concentrations were as follows: Upper Providence River (16.01 µg/l), Edgewood Shoals area (14.89 µg/l), Pawtuxet River area (9.63 µg/l), and the Lower Providence River (9.08 µg/l). Overall, chlorophyll ranged between 4.00 µg/l and 38.70 µg/l with an overall average of 12.55 µg/l. The chlorophyll data from this date is presented in the map below:
Water Column Clarity
Water clarity was measured at eight locations in the Providence and Seekonk Rivers on June 20, 2018. A total of 0.20 inches of rain occurred during the 2 days prior to sampling. Overall, average clarity decreased from the previous week by 0.3 m, to 1.3 m. The largest increase (1.0 m) was observed at Phillipsdale Landing. Secchi depth ranged from 0.97 m at India Point Park to 1.50 m at Bullock Reach and Conimicut Point. There was no evidence of a north to south water clarity gradient.
Fixed Site Network
Phillipsdale
This week at Phillipsdale, data revealed overall good water quality, with little to no stratification observed. Over the course of the week there was only trace amounts of rainfall recorded. Surface salinities increased over the course of the week with an overall average of 14.0 ppt, a minimum of 5.0 ppt, and a maximum of 24.7 ppt. Bottom salinity increased slightly and fluctuated with the tides over the course of the week with an average of 20.9 ppt and a range 7.6 ppt – 26.4 ppt. Surface temperatures increased slightly through the week, but were overall very similar to the previous week with an average surface temperatures of 19.4oC and a range of 17.2oC – 21.8oC; bottom temperatures increased by about 2oC on overall with a weekly average of 18.3oC and range of 16.0oC – 20.7oC. Surface chlorophyll decreased over the course of the week and had a weekly average of 13.3 ug/L, and a daily average peak of about 34.0 ug/L. Dissolved oxygen (DO) for the week was good at the surface and fair at the bottom. Surface DO decreased as compared to the previous week and averaged 7.7 mg/L and had a minimum of 3.5 mg/L. Dissolved oxygen in the bottom waters did not have any instances of hypoxia (below 2.9 mg/L) and had a weekly average of 5.5 mg/l and a minimum of 3.3 mg/L. Note that tidal fluctuations and Blackstone River flow greatly influence bottom DO, temperature and salinity at this location.
Bullocks Reach
New sondes have been deployed at the Bullock Reach buoy site for the 2018 season. These sondes are called EXO sondes from YSI, and are the newest technology from the company. The sondes at Bullock Reach were deployed on June 6th, however due to a data recording problem, data for the surface sonde is available only from June 13th through the 16th. The Bullock’s Reach sonde data revealed relatively good conditions over the week, with no indications of hypoxia. Surface temperatures increased slightly throughout the week and averaged 18.8oC, and had an average salinity of 25.5 ppt. Chlorophyll also increased slightly with an average of 10.2 ug/L and a peak daily average of about 12.5ug/L on the 16th. Dissolved oxygen (DO) at the surface was good with a weekly average of 8.0 mg/l and a minimum of 6.5 mg/l. Temperatures at the mid-depth sonde also had a slight increase, with a weekly average temperature of 17.7oC, and a weekly average salinity of 29.3 ppt. DO at the mid sonde was good and averaged 6.6 mg/l over the course of the week, with a minimum of 4.6 mg/L. Chlorophyll at the mid-depth sonde was much lower than the surface with an average of 1.5 ug/L. The bottom sonde also showed a slight increasing trend in temperature through the week with an average temperature of 16.3oC and had an average salinity of 29.6 ppt. Dissolved oxygen at the bottom averaged 5.2 mg/l for the week and had a minimum DO of 3.2 mg/L.
Water Column Profiles
R/V Monitor's Blog
The R/V Monitor was out on the upper Bay twice this week. First, on Tuesday, June 19th, the NBC boating crew received its annual man overboard training provided by the U.S Coast Guard Reserve. In the afternoon, sondes were changed out at the Bullock's Reach buoy. Sara captained the boat while monitoring professionals Mike and Jeffrey changed out the sondes. The weather was sunny, warm and windy with choppy waters this day. On Wednesday, June 20th, the crew was out collecting nutrients 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. Jeffrey captained the boat while monitoring professionals Heather and Steve collected the samples and data. It was sunny and warm all day with calm waters in the morning which became somewhat choppy in the afternoon as the wind picked up. Below is a photo taken during the man overboard training provided on Tuesday.
