Historical News
Nutrients Sampling
R/V Monitor's Blog
On Wednesday, August 25th, 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. Jeff captained the boat while monitoring professionals Amanda, Jeff, and summer intern Mackenzie collected the samples and data. It was a sunny, hazy, hot and humid day with no wind early on but a light breeze developed from the southwest as the day progressed. The water was extremely calm all day. The photo below was taken at Edgewood Yacht Club and shows the NBC's Seabird water column profiling instrument in the foreground.
Surface Mapping
Data were collected on August 25, 2021, while the R/V Monitor was underway collecting nutrient samples in the Seekonk and Providence River estuaries. The average chlorophyll concentrations were good to fair in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Seekonk River (3.25 µg/L), Upper Providence River (4.20 µg/L), Edgewood Shoals area (5.63 µg/L), Pawtuxet River area (4.64 µg/L), and Lower Providence River (12.73 µg/L). Overall, chlorophyll ranged between 2.11 µg/L and 19.62 µg/L with an overall average of 7.34 µg/L. The chlorophyll data from this date are presented in the map below:
Phytoplankton Sampling
Phytoplankton samples were collected on August 11, 2021 at Bullock Reach and analyzed in the laboratory shortly after collection. Sondes data revealed the surface water temperature was 23.34°C, salinity was 42.43 psu, and chlorophyll a was 8.2 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a light green/brown color and had a quick 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 8,332,000 cells per Liter. The flagellates were found at 5,636,000 cells/L. The most predominant phytoplankton genus was Leptocylindrus spp. at 2,112,000 cells/L. Other representative genera include Prorocentrum spp., Skeletonema spp., Chaetoceros spp., and Thalassiosira spp.
200x phase contrast micrograph of Ditylum brightwellii.
Surface Mapping
Data were collected on August 18, 2021 while the R/V Monitor was underway collecting bacteria samples in the Seekonk and Providence River estuaries. The average chlorophyll concentrations were fair in the areas surveyed. From north to south, average chlorophyll concentrations were as follows: Seekonk River (12.46 µg/L), Upper Providence River (13.45 µg/L), Edgewood Shoals area (12.40 µg/L), Pawtuxet River area (11.66 µg/L), and Lower Providence River (8.52 µg/L). Overall, chlorophyll ranged between 1.69 µg/L and 30.97 µg/L with an overall average of 11.44 µg/L. The chlorophyll data from this date are presented in the map below:
