Historical News
Surface Mapping
Surface chlorophyll data were collected on October 23, 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 0.78 µg/L to 5.11 µg/L with an average of 2.96 µg/L. The chlorophyll concentrations from this date are presented in the map below using Inverse Distance Weighting (IDW) interpolation.
Bacteria Sampling
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 3, 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 quick filtration time. The filtrate was slightly cloudy and reddish brown with some particulates. The analysis of the quantitative whole water sample revealed a total of 1,712,000 cells/L. The microflagellates were found at 112,000 cells/L. The most predominant phytoplankton genera were Heterocapsa spp. at 1,232,000 cells/L, Prorocentrum spp. at 108,000 cells/L, and Leptocylindrus spp. at 100,000 cells/L. Chaetoceros socialis, shown here in a 100x phase contrast micrograph, is a species of diatom belonging to one of the most diverse genera of marine planktonic organisms. Due to their high growth rates, research on the use of Chaetoceros species in biotechnology is ongoing. They are currently used in commercial aquacultures and studies suggest that they have enormous potential for producing biofuel.
Water Column Profiles
Water column profiles were conducted at seven locations in the Providence and Seekonk River estuaries on April 16, 2024 using a Seabird Electronics profiler. In the five days leading up to the survey, 1.01 inches of precipitation were recorded at T.F. Green. Most sites were strongly stratified this week, with the exception of Phillipsdale Landing, which was dominated by freshwater.
Water Column Clarity
Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on October 23, 2024. No precipitation was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 5.0 meters. The lowest clarity this week (4.7 meters) was measured at Conimicut Point, while the greatest clarity (5.5 meters) was measured at Edgewood Yacht Club. There was no distinct north-to-south trend of water clarity among the sites this week. Overall, water clarity increased from the previous measurements (data collected October 17, 2024).