Historical News
June 12, 2024
Phytoplankton Sampling
Phytoplankton samples were collected on June 12, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection. Sonde data revealed the surface water temperature was 19.68°C, salinity was 24.22 psu, and chlorophyll a was 9.89 ug/L. The qualitative tow net sample had a short filtration time, and the filtrate was mostly clear. The analysis of the quantitative whole water sample revealed a total of 12,732,000 cells per Liter. The most predominant phytoplankton genus was Skeletonema spp. at 12,408,000 cells/L. Other representative genera include Chaetoceros spp. and Leptocylindrus spp. Prorocentrum spp. (see 200x phase contrast image below) is a dinoflagellate genus containing several toxic and harmful species. P. micans is one of the most common species in the genus. Prorocentrum is found in cold, temperate to tropical waters. This genus forms extensive red tides in many parts of the world, though blooms are usually harmless. It may excrete substances that inhibit diatom growth, but these substances do not enter the food chain or affect organisms at higher trophic levels.
May 29, 2024
Phytoplankton Sampling
Phytoplankton samples were collected on May 29, 2024 at Bullock Reach and analyzed in the laboratory shortly after collection.
Sonde data revealed the surface water temperature was 20.1°C, salinity was 15.49 psu, and chlorophyll a was 12.1 ug/L.
The qualitative tow net sample had a moderate filtration time, and the filtrate was a dark tan/brown color and had particulate matter.
The analysis of the quantitative whole water sample revealed a total of 7,565,000 cells per Liter. The most predominant phytoplankton genus was Skeletonema spp. at 7,276,000 cells/L. Other representative genera include Chaetoceros spp. and Leptocylindrus spp. Chaetoceros spp. (see 200x phase contrast image below) is a genus of diatoms found in Narragansett Bay and is one of the most common and most diverse genera of marine planktonic diatoms with over 200 accepted species. Due to its high growth rates, research has been conducted into potential uses of Chaetoceros in biotechnology.
Week of September 17 - September 23, 2023
Nutrients Sampling
Nutrient samples were collected from 14 river stations and 8 bay stations on September 20th, 2023. Edgewood Shoal was sampled at the surface and bottom; all other bay stations were sampled at the surface only. In the five days prior to sampling, there were 1.55 inches of rainfall recorded at T.F. Green with the majority accumulated during a heavy rain event on September 18th.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) concentrations were observed at Ten Mile River at Roger Williams Ave. (TN = 1,305 ppb, TDN = 1,195 ppb, DIN = 771.5 ppb; all averaged with duplicates). The lowest TN and TDN were observed at Woonasquatucket River @ Valley St. (TN = 665 ppb, TDN = 635 ppb), while the lowest DIN was at Coles River @ Milford Rd. (DIN = 139.2 ppb).
Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations were observed at Pawtuxet Cove (TN = 1,120 ppb, TDN = 1,070 ppb, DIN = 638.3 ppb). The lowest surface TN was observed at Conimicut Point (TN = 799 ppb), while the lowest surface TDN and DIN were observed at Bullock Reach (TDN = 607 ppb, DIN = 300 ppb). Chlorophyll a concentrations at the surface bay stations averaged 2.8 μg/L overall with a maximum of 4.2 μg/L at Bullock Reach Buoy.
Week of September 3 - 9, 2023
Nutrients Sampling
Nutrient samples were collected from seven river stations and seven bay stations on September 6th, 2023. All bay stations were sampled at the surface and bottom. In the five days prior to sampling, there was no rainfall recorded at T.F. Green.
Among the river stations sampled, the highest total nitrogen (TN), total dissolved nitrogen (TDN), and dissolved inorganic nitrogen (DIN) concentrations were observed at Pawtuxet River @ Broad St (TN = 1,560 ppb, TDN = 1,510 ppb, DIN = 1,271.3 ppb). The lowest TN, TDN, and DIN were observed at Moshassuck River @ Higginson Ave. (TN = 539 ppb, TDN = 640 ppb, DIN = 483 ppb).
Among the bay stations sampled, the highest surface TN, TDN, and DIN concentrations were observed at Pawtuxet Cove (TN = 994 ppb, TDN = 799 ppb, DIN = 633.4). The lowest surface TN was observed at the Bullock Reach Buoy (TN = 438 ppb), the lowest surface TDN was observed at Pomham Rocks (TDN = 155 ppb), and lowest surface DIN was at Edgewood Yacht Club (DIN = 20 ppb). Chlorophyll a concentrations at the surface bay stations averaged 4.5 μg/L overall with a maximum of 7.9 μg/L at Conimicut Point.
Week of August 20 - 26, 2023
Nutrients Sampling
Nutrient samples were collected from fourteen river stations and eight bay stations on August 23rd, 2023. Edgewood Shoal was sampled at the surface and bottom; all other bay stations were sampled at the surface only. In the five days prior to sampling, there were 2.16 inches of rainfall recorded at T.F. Green due to a heavy rain event on August 18th.
Among the river stations sampled, the highest total nitrogen (TN) concentration was observed at Pawtuxet River @ Broad Street (TN = 1,815 ppb, average of duplicates), while the highest total dissolved nitrogen (TDN) and dissolved inorganic nitrogen (DIN) concentrations were at Ten Mile River @ Central Ave. (TDN = 1,480 ppb, DIN = 1,013.9 ppb). The lowest TN and TDN were observed at Ten Mile River @ Roger Williams Ave. (TN = 510 ppb, TDN = 666 ppb), while the lowest DIN was at Coles River @ Milford Rd. (97.4 ppb, average of duplicates).
Among the bay stations sampled, the highest surface TN, TDN, and DIN were observed at Pawtuxet Cove (TN = 1,020 ppb, TDN = 892 ppb, DIN = 662.3 ppb). The lowest surface TN and DIN were observed at the Bullock Reach Buoy (TN = 540 ppb, DIN = 119.5 ppb), while the lowest surface TDN was at Conimicut Point (276 ppb). Chlorophyll a concentrations at the surface bay stations averaged 3.95 μg/L overall with a maximum of 7.02 μg/L at Conimicut Point.
