Week of November 19 – 25, 2023
Fixed Site Network
Phillipsdale Landing
Overall, water quality was good at Phillipsdale Landing this week. There were 1.82 inches of precipitation recorded at T.F. Green this week, 1.71 of which occurred on 11/22. Blackstone flows were higher than historical averages all week, but particularly following the 11/22 rain event. Surface salinity averaged 8.8 ppt and ranged from 2.9 ppt to 20.7 ppt. Bottom salinity averaged 21.4 ppt and ranged from 6.5 ppt to 27.7 ppt. Temperatures continued to decline, averaging 8.1°C at the surface and ranging from 5.1°C to 10.5°C. At the bottom, temperatures averaged 10.4°C and ranged from 7.2°C to 12.4°C.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold of 2.9 mg/L at both the surface and bottom all week. Surface DO was slightly higher than the previous week, averaging 10.2 mg/L and ranging from 8.3 to 11.8 mg/L. Bottom DO averaged 7.8 mg/L and ranged from 6.4 mg/L to 11.1 mg/L. Chlorophyll readings remained low, averaging 0.6 ug/L at the surface and 2.6 ug/L at the bottom. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
The sondes at Bullock Reach have been retrieved for the 2023 season.
Week of December 10 - 16, 2023
Phytoplankton Sampling
Phytoplankton samples were collected on December 13, 2023 at Bullock’s Reach and analyzed in the laboratory shortly after collection. It was calm and brisk on Narragansett Bay with an outgoing tide. The qualitative tow net sample had a moderate filter time, and the filtrate was a light brown color with some particulate matter. The analysis of the quantitative whole water sample revealed a total of 81,000 cells per liter. The micro flagellates were found at 11,000 cells/L. The most predominant phytoplankton genus was
Skeletonema spp. at 31,000 cells/L. Other representative genera include
Leptocylindrus spp. and
Guinardia spp. The photo featured this week is a 200x phase-contrast image of
Staurastrum, a type of green algae in the desmid family. It gets its name from the Greek “stauron” which means cross and “astron” which means star. It is made of highly constricted unicells that are radially symmetrical and can be distinguished by cell wall patterns.
Staurastrum is a food source for zooplankton in the aquatic food web.
Week of December 10 - 16, 2023
Water Column Clarity
Water clarity was measured at eight locations in the Providence River and Seekonk River estuaries on December 13th, 2023. Rainfall totaling 2.29 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 1.3 meters, compared to 4.5 meters on the previous survey (November 30th). The lowest clarity this week (0.7 meters) was measured at Phillipsdale Landing, while the greatest clarity (1.9 meters) was measured at Conimicut Point. There was a general north-to-south gradient of increasing water clarity among the sites this week.
Week of November 26 - December 2, 2023
Water Column Clarity
Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on November 30th, 2023. Rainfall totaling 0.69 inches was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 4.5 meters, compared to 4.7 meters on the previous survey (November 15th). The lowest clarity this week (3.0 meters) was measured at Phillipsdale Landing, while the greatest clarity (5.5 meters) was measured at Bullock Reach. There was a general north-to-south gradient of increasing water clarity among the sites this week.
Week of November 12 - 18, 2023
Water Column Clarity
Water clarity was measured at seven locations in the Providence River and Seekonk River estuaries on November 15th, 2023. Trace amounts of rainfall was recorded at TF Green in the five days prior to the survey. Secchi depth averaged 4.7 meters, compared to 3.0 meters on the previous survey (November 1st). The lowest clarity this week (3.4 meters) was measured at India Point, while the greatest clarity (5.8 meters) was measured at Conimicut Point. There was a general north-to-south gradient of increasing water clarity among the sites this week.
