Historical News
Phytoplankton Sampling
Phytoplankton samples were collected on April 21, 2021 at Bullock Reach and analyzed in the laboratory shortly after collection. It was choppy and windy on Narragansett Bay with brisk conditions. Sondes data revealed the surface water temperature was 12.63°C, salinity was 18.3 psu, and chlorophyll a was 1.62 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a light golden color and had a quick filter time. The tow net sample was analyzed qualitatively for microorganisms using 100x 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 518,000 cells per Liter. The flagellates were found at 60,000 cells/L. The most predominant phytoplankton genus was Chaetoceros spp. at 330,000 cells/L. Representative genera include Skeletonema spp., Thalassiosira spp., and Guinardia spp.
200x phase contrast micrograph of Thalassiosira spp.
Surface Mapping
Data were collected on April 28, 2021 while the R/V Monitor was underway collecting bacteria samples in the Seekonk and Providence River estuaries. The chlorophyll concentrations were 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 (3.33 µg/L), Upper Providence River (3.00 µg/L), Edgewood Shoals area (3.93 µg/L), Pawtuxet River area (7.38 µg/L), and Lower Providence River (7.18 µg/L). Overall, chlorophyll ranged between 0.65 µg/L and 25.48 µg/L with an overall average of 4.51 µg/L. The chlorophyll data from this date are presented in the map below:
Phytoplankton Sampling
Phytoplankton samples were collected on April 7, 2021 at Bullock Reach and analyzed in the laboratory shortly after collection. It was an awesome and warm day on Narragansett Bay. Sondes data revealed the surface water temperature was 8.93°C, salinity was 22.18 psu, and chlorophyll a was 1.9 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a light golden color and had a quick filter time. The tow net sample was analyzed qualitatively for microorganisms using 100x 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 1,335,000 cells per Liter. The flagellates were found at 25,000 cells/L. The most predominant phytoplankton was Chaetoceros spp. at 623,000 cells/L. Representative genera include Skeletonema spp., Thalassiosira spp., and Guinardia spp.
200x phase contrast micrograph Chaetoceros socialis.
R/V Monitor's Blog
On Wednesday, April 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. Jeffrey captained the boat while monitoring professionals Mike and Daryll collected the samples and data. NBC's Public Affairs Manager was also onboard this day with a reporter and photographer who were doing a story on Combined Sewer Overflows. It was a sunny day with a strong wind out of the south, making for very choppy waters. The photo taken this day features the Pomham Rocks lighthouse.
Surface Mapping
Data
were collected on April 21, 2021 while the R/V Monitor was underway collecting nutrient
samples in the Providence River estuary. The chlorophyll concentrations were
good in the areas surveyed. From north to south, average chlorophyll
concentrations were as follows: Upper Providence River (2.21 µg/L), Edgewood
Shoals area (2.36 µg/L), Pawtuxet River area (1.24 µg/L), and Lower Providence
River (1.93 µg/L). Overall, chlorophyll ranged between 0.52 µg/L and 4.39 µg/L
with an overall average of 1.97 µg/L. The chlorophyll data from this date are
presented in the map below:
