Historical News
R/V Monitor's Blog
The R/V Monitor was out on the upper Bay twice this week. First, on Tuesday, June 13th, the crew was out in the morning conducting underwater benthic surveys in the Providence River just off of Edgewood Yacht Club and another at Sabin Point. Jeff captained the boat while monitoring professional Michael, along with NBC scientist Eliza, conducted the transects. DEM's Chris was also aboard the vessel in the morning, doing some cross-training activities. In the afernoon, the crew investigated a report of a small number of dead fish by the hurricane barrier. Many healthy fish were also observed, and the dissolved oxygen readings in the area were quite good. The fish were most likely bait fish being thrown in the water by fishermen that were done fishing for the day. The weather was hazy, hot and humid with calm waters and a southwest wind at 10 knots. On Wednesday, June 14th, the crew was out on the upper Bay collecting bacteria samples, taking Secchi Disk 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 Michael, Amanda and David collected the samples and data. It was a beautiful day with sunny skies, a slight breeze and fairly calm waters all day. The boat was removed from the water at the end of the day for maintenance. The photo below shows the sun shining down on the Bay this day.
Surface Mapping
Data was collected on June 14, 2017 while the R/V Monitor was underway collecting bacteria samples and performing vertical profiles in the Providence and Seekonk River estuaries. The chlorophyll concentrations ranged from fair to poor with evidence of a north-south gradient. The lowest average chlorophyll concentrations were observed in the Seekonk River (5.51 µg/l) and Upper Providence River (6.98 µg/l). The highest average concentrations were seen in the Edgewood Shoals area (25.08 µg/l) and the Lower Providence River (25.76 µg/l) . Overall, chlorophyll ranged between 1.1 and 37.8 µg/l with an overall average of 14.74 µg/l. The chlorophyll data from this date is presented in the map below:
Phytoplankton Sampling
Phytoplankton samples were collected at Bullock’s Reach on May 10, 2017 and analyzed in the laboratory shortly after collection. It was breezy and cold on Narragansett Bay. The surface water temperature was 12.61oC, salinity was 16.01 psu, and chlorophyll a concentration was 14.0 ug/L.
The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a light brown color with a short filter-ability 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 652,000 cells/liter.
There was a significant decrease in the abundance of phytoplankton in this examination as compared to last month. While the phytoplankton cell abundance on April 26th was indicative of a phytoplankton bloom, the bloom was over by May 10th. This is a typical pattern, as blooms are characterized by exponential growth as the phytoplankton use all available nutrients, followed by a crash in population when nutrients are depleted. The flagellates were the most predominant phyla at 421,000 cells/L, followed by diatom genus Skeletonema at 209,000 cells/L. Other representative genera include the dinoflagellates Prorocentrum and Heterocapsa, and a pennate diatom species.
200x phase contrast micrograph of a single Thalassiosira spp. cell. Thalassiosira is a chain-forming diatom with disk-shaped cells.
R/V Monitor's Blog
The R/V Monitor was out on the Bay three times this week. First on Monday, June 5th, the crew was out retrieving the Bullock's Reach buoy electronics so that communications issues with the buoy could be investigated and resolved. Internal data-logging sondes remain deployed at this site to prevent any data gaps while the electronics are being evaluated. Jeff captained the boat, while monitoring professionals Bekki, Mike and Heather worked on the buoy. It was a cool drizzly day, but the water remained very calm while buoy work was performed. On Wednesday, June 7th, the crew was out on the upper Bay collecting nutrients samples, taking Secchi Disk 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 Fern and Mike collected the samples and data. The day began cool and cloudy with a persistent light wind from the Northeast, and became sunny in the afternoon. On Thursday, June 8th, the crew was out for the last time this week, conducting underwater benthic video transects in the Bullock's Reach area. Jeff captained the boat while monitoring professionals Stephen and Heather worked the underwater sled and camera system. It was a sunny day with a light breeze and calm waters. The below photo taken on June 7th shows a nice view of the Seekonk River.
Surface Mapping
Data was collected on June 7, 2017 while the R/V Monitor was underway collecting nutrient samples and performing vertical profiles in the Providence and Seekonk River estuaries. The chlorophyll concentrations were mostly good with two regions displaying fair chlorophyll concentrations. The lowest average chlorophyll concentrations were observed in Upper Providence River (4.64 µg/l) and the Edgewood Shoals Area (4.55 µg/l). The highest average concentrations were seen in the Lower Providence River (9.29 µg/l). Overall, chlorophyll ranged between 1.5 and 25 µg/l with an overall average of 6.05 µg/l. The chlorophyll data from this date is presented in the map below:
