Snapshot of the Bay

Historical News

Week of March 25 – 31, 2018

Benthic Video Blog

The boat crew conducted a benthic video survey along the Sabin transect on March 27^th. Unfortunately, one of the scale lasers failed during deployment, so only one beam was visible in footage. Visibility through the water column was good, and interesting observations were made. The bottom was characterized by muddy sand with some areas of extensive shell hash and rubble. Some boulders were observed, but the boat missed the main boulder field often observed along this transect. There was a lot of bushy algae or diatom growth observed, typical for the early spring, as well as small patches or rafts of Ulva. Extensive areas of an unknown brown sheet-like alga (see photo) were observed. As usual, some litter was also observed along the transect. Additional common sights included small burrows and tubes built by infauna (e.g., parchment tube worms, Chaetopteridae) and dense assemblages of Nassariid mudsnails. Dense areas of amphipod tube mats and Beggiatoa bacteria growth were not observed this week.

Week of February 18 - 24, 2018

Benthic Video Blog

The boat crew conducted benthic video surveys along all three routine transects (Edgewood, Bullock Reach, and Sabin) on February 20^th. Scale lasers were in use for all three transects, separated by 28 cm. Visibility was murky, though some interesting features were visible. The Sabin transect yielded very little useable footage due to sled entanglement with boulders and debris (rope or line).

All three transects were characterized by muddy-sand bottom with trace amounts of shell hash and shell rubble and very sparse algae. The Sabin transect also includes a boulder/cobble zone, with some attached algae and sponges. Evidence of large tunneling organisms (e.g., the mantis shrimp, Squilla) was observed along all transects. Sightings of arthropods were relatively rare, though tracks and trails were frequently observed and a mantis shrimp was spotted at Edgewood (photo below). Other noteworthy observations included small fish at Bullock Reach and seastars at Edgewood. Unfortunately, litter (e.g., bottles, tire) was observed at these two locations as well. Additional common sights along all three transects were small burrows and tubes built by infauna (e.g., parchment tube worms, Chaetopteridae), diatom felt, and Nassariid mudsnails. Dense areas of amphipod tube mats, rafting algae, or Beggiatoa bacteria growth were not observed this week.

Week of November 4 - 10, 2018

Phytoplankton Sampling

Phytoplankton samples were collected at Bullock's Reach on November 7, 2018 and analyzed in the laboratory shortly after collection. It was a sunny day on Narragansett Bay. Sondes data revealed the surface water temperature was 12.55^oC, salinity was 16.00 psu, and chlorophyll a was 1.6 ug/L. The plankton tow net sample was filterable with a 20 micron mesh. The filtrate was golden dark brown with a short filter time. Jellyfish were noticed in the sample. 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 56,000 cells per Liter. The most predominant phytoplankton was the pennate diatoms at 6,000 cells/L. The flagellates were found at 52,000 cells/L and other representative genera include Prorocentrum spp. and Odontella spp.

200x phase contrast micrograph of Thalassionema spp.

Week of November 25 - December 1, 2018

R/V Monitor's Blog

On Wednesday, November 28th, the crew of the R/V Monitor was out on the upper Bay collecting bacteria 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. Sara captained the boat while monitoring professionals Fern and Mike collected the samples and data. It was a cool day with winds out of the south, making the water choppy. Below is a photo taken this day of Phillipsdale landing in the Seekonk River, where NBC's fixed site monitoring station is located.

11-28-18 Phillipsdale.jpg

Week of November 25 – December 1, 2018

Bacteria Sampling

Twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers on November 28, 2018; five of these stations were also sampled for enterococci bacteria. Heavy precipitation occurred in the three days prior to sampling, totaling 2.78 inches. Over an inch of rainfall was recorded on both November 25^th and 26^th.

The fecal coliform geometric mean increased from the previous sampling to 482 MPN/100 mL. Fecal coliform concentrations were higher in the Providence River (geometric mean: 593 MPN/100 mL) than in the Seekonk River (geometric mean: 310 MPN/100 mL). The maximum fecal coliform concentration of 2300 MPN/100 mL was measured in the Providence River at Gaspee Point. The greatest fecal coliform value in the Seekonk River, 930 MPN/100 mL, occurred at the Narragansett Boating Center and in one of the Phillipsdale Landing samples. Geometric mean results indicate both rivers exceeded primary contact and shellfishing standards.

The overall enterococci geometric mean was 347 MPN/100 mL. Concentrations ranged from approximately 252 MPN/100 mL at Phillipsdale Landing (geometric mean of two duplicates) to 703 MPN/100 mL at Point Street Bridge. The geometric mean of all results exceeded the state primary contact standard.

Please note: the results of NBC's fecal coliform and enterococci monitoring are for informational/research purposes only and are not intended to suggest official state compliance with bathing or shellfishing standards.