Historical News
Phytoplankton Sampling
Phytoplankton samples were collected on June 1, 2022 at Bullock Reach and analyzed in the laboratory shortly after collection. Sondes data revealed the surface water temperature was 20.25°C, salinity was 24.67 psu, and chlorophyll a was 5.85 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was a yellow-green light brown color and had a medium 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 29,464,000 cells per Liter. The micro flagellates were found at 96,000 cells/L. The most predominant phytoplankton genus was Skeletonema spp. at 29,168,000 cells/L. Pseudo-nitzschia spp. was found in the tow net sample and whole water sample. Some of these diatoms were found dead or oddly shaped, unlike the previous examination. Other representative genera include Leptocylindrus spp. and Chaetoceros spp.
200x phase contrast micrograph of diatoms.
Benthic Video Blog
The boat crew conducted a benthic video survey along Bullock Reach, Edgewood, and Sabin transects on June 14, 2022. Scale lasers were used in the footage, separated by 29 cm. Visibility through the water column varied at each site from poor to fair. The bottom of all sites was characterized by sands and muds, with a few boulders and cobbles. Dense patches of shell hash and rubble were also observed frequently at Bullock Reach and Sabin. Algal coverage was diverse this week. Sabin experienced particularly dense coverage by Ulva, red sheet-like algae, and branching algae. Bullock Reach was dominated by sparse filamentous algae, while Edgewood was also dominated by Ulva and branching species. Infaunal activity was moderate (higher activity at Edgewood); large burrows, likely from mantis shrimp (Squilla), and some small burrows were present. Assemblages of small tube-building fauna were also common at all sites but more frequent at Edgewood. General biotic activity was moderate as noted by frequent tracks and trails (especially at Edgewood and Bullock Reach). Rare benthic video sights included horseshoe crabs spotted at Sabin and Edgewood, as well as moon snail eggs at Sabin, and a winter flounder at Bullock Reach. Common observations consisted of Nassariid mudsnails (Bullock Reach), slipper snail Crepidula (all sites), spider crabs (all sites, photo below), hermit crabs (all sites), boring sponges (all sites), channeled whelk (Bullock Reach and Sabin), soft-shell clam mya (Bullock Reach and Edgewood), blue crab (Edgewood), and egg masses produced by the lugworm Arenicola (all sites). Edgewood had what appeared to be amphipod tubes, though not at mat-like densities.
Please note: this blog publication has been post-dated to retain chronological order as a backlog of video footage is reviewed.
Surface Mapping
Data were collected on June 22, 2022, while the R/V Monitor was underway collecting bacteria 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 (13.00 µg/L), Upper Providence River (8.17 µg/L), Edgewood Shoals area (6.35 µg/L), Pawtuxet River area (5.89 µg/L), and Lower Providence River (4.67 µg/L). Overall, chlorophyll ranged between 1.47 and 31.70 µg/L with an overall average of 8.57 µg/L. The chlorophyll data from this date are presented in the map below:
Water Column Profiles
Nutrients Sampling
