Historical News
Bacteria Sampling
On November 20th, 2024, twenty stations were sampled for fecal coliform bacteria in the Providence and Seekonk Rivers; five of these stations were also sampled for enterococci bacteria. In the five days prior to sampling, no precipitation was recorded at TF Green. Overall, bacteria counts in both the Providence and Seekonk Rivers were lower compared to previous sampling (November 7th, 2024).
Fecal coliform counts were higher in the Seekonk River sites than in the Providence River sites (geometric means of 14 MPN/100 mL and 9 MPN/100 mL, respectively). The maximum count (93 MPN/100 mL) was measured at Point St. Bridge.
Enterococci results had an overall geometric mean of 15 MPN/100 mL. Enterococci counts ranged from <10 MPN/100 mL at most sites to 75 MPN/100 mL at Point St. Bridge.
The next scheduled sampling date is December 4th.
The table below lists the Rhode Island bacteria standards for primary contact and shellfishing established by the Rhode Island Department of Environmental Management (RIDEM). RIDEM defines primary contact as any recreational activities in which there is prolonged and intimate contact with water, involving considerable risk of ingesting water (e.g., swimming, diving, water skiing and surfing). Please note that the RIDEM bacteria standards are provided here for informational purposes only and are not intended to indicate official state compliance with primary contact or shellfishing standards.
| | Fecal Coliform | Enterococci |
| Primary Contact1 | Geometric mean ≤50 MPN/100 mL | Geometric mean ≤35 colonies/100 mL |
| Shellfishing | Geometric mean ≤14 MPN/100 mL | NO ENTEROCOCCI CRITERIA |
Phytoplankton Sampling
Phytoplankton samples were collected on October 30, 2024 at Bullock’s Reach and analyzed in the laboratory shortly after collection. Weather conditions and Sonde data were not recorded on this day. The qualitative tow net sample had a moderate filtration time. The filtrate was slightly cloudy with some golden brown particulates. The analysis of the quantitative whole water sample revealed a total of 260,000 cells/L. The microflagellates were found at 100,000 cells/L. The most predominant phytoplankton genera were Chaetoceros spp. at 104,000 cells/L, Leptocylindrus spp. at 26,000 cells/L, and Skeletonema spp. at 18,000 cells/L. Proboscia alata, shown here in a 100x phase contrast micrograph, is a solitary or chain-forming diatom that can measure up to 1mm in length. They are identified by the presence of a proboscis with a truncated tip and offset claspers. These diatoms are an oceanic, temperate water species and are sometimes found near the coast.
Water Column Profiles
Water Column Profiles
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries on July 3, 2024 using a Seabird Electronics profiler. In the five days leading up to the survey, 1.53 inches of precipitation were recorded at T.F. Green. Sites ranged from weakly to moderately stratified this week.
Surface Mapping
Surface chlorophyll data were collected on November 7, 2024, while the R/V Monitor was underway collecting nutrient samples in the Providence and Seekonk River estuary. The average chlorophyll concentrations were categorized as good in all areas surveyed. Overall, chlorophyll ranged from 0.53 µg/L to 17.57 µg/L with an average of 2.89 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
