Historical News

Week of November 26 - December 2, 2023

Phytoplankton Sampling

Phytoplankton samples were collected on November 30, 2023 at Bullock Reach and analyzed in the laboratory shortly after collection. It was sunny and brisk on Narragansett Bay with calm conditions and a southwest wind at less than 10 kts. The qualitative tow net sample had a quick filter time, and the filtrate was a light tan color. The analysis of the quantitative whole water sample revealed a total of 153,000 cells per liter. The microflagellates were found at 52,000 cells/L. The most predominant phytoplankton genus was Skeletonema spp. at 65,000 cells/L. Other representative genera include Chaetoceros spp. and Eucampia spp. Chaetoceros socialis (see image, 200x phase contrast) is a diatomic phytoplankton found in marine and brackish waters. These phytoplankton have a characteristic linear colonial growth habit and their very long, overlapping, spines are thought to minimize sinking rates.​
2023_11_30_Chaetoceros_socialis_200xPC.JPG

Week of November 13 - 19, 2023

Phytoplankton Sampling

Phytoplankton whole water sample was collected on November 15, 2023 at Bullock Reach and analyzed in the laboratory shortly after collection. No qualitative tow-net sample was collected this day. It was calm, clear, and very brisk on Narragansett Bay with clear water about 6.2 meters down. Sonde data revealed the surface water temperature was 10.4°C, salinity was 24.8 psu, and chlorophyll a was 0.8 ug/L. The analysis of the quantitative whole water sample revealed a total of 77,000 cells per Liter. The microflagellates were found at 39,000 cells/L. The most predominant phytoplankton genus was Skeletonema spp. at 13,000 cells/L. Other representative genera include Leptocylindrus spp., Chaetoceros spp. and Pseudo-nitzchia spp.

Week of October 29 - November 4, 2023

Phytoplankton Sampling

​Phytoplankton samples were collected on November 1, 2023 at Bullock Reach and analyzed in the laboratory shortly after collection. It was cloudy and brisk on Narragansett Bay with a northwest wind at 10 kts. Sonde data revealed the surface water temperature was 13.08°C, salinity was 22.63 psu, and chlorophyll a was 1.06
ug/L. The qualitative tow net sample had a moderate filter time, and the filtrate was a light yellow-brown color. The analysis of the quantitative whole water sample revealed a total of 119,000 cells per liter. The micro flagellates were found at 62,000 cells/L. The most predominant phytoplankton genus was Skeletonema spp. at 46,000 cells/L. Other representative genera include Leptocylindrus spp., Eucampia spp., and Prorocentrum spp. Prorocentrum micans (see image, 200x phase contrast) is a tear-dropped shaped dinoflagellate that is often found in Narragansett Bay during the late summer-autumn time period. This species can form extensive blooms but is  considered harmless.

2023_11_01_Prorocentrum_micans_200xPC_200xPC.JPG

Week of November 5 – 11, 2023

Fixed Site Network

Phillipsdale Landing

Overall, water quality was good at Phillipsdale Landing this week. Sondes were swapped this week on the morning of November 7th. There were 0.18 inches of precipitation recorded at T.F. Green this week. Blackstone River flow was higher than normal for this time of year. Surface salinity averaged 5.9 ppt and ranged from 2.0 ppt to 19.3 ppt. Bottom salinity averaged 21.1 ppt and ranged from 4.6 ppt to 28.3 ppt. Temperatures decreased this week, averaging 10.6°C at the surface and ranging from 8.1°C to 12.6°C. At the bottom, temperatures averaged 13.5°C and ranged from 10.5°C to 15.3°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 remained similar to the previous week, averaging 9.8 mg/L and ranging from 7.2 to 10.8 mg/L. Bottom DO averaged 5.9 mg/L and ranged from 4.0 mg/L to 10.0 mg/L. Chlorophyll readings remained low, averaging 0.6 ug/L at the surface and 0.9 ug/L at the bottom. Maximum chlorophyll at the surface was only 1.0 ug/L. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach

Overall, water quality was good at Bullock Reach this week. Salinity averaged 24.4 ppt, 27.5 ppt, and 29.7 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 18.5 – 27.2 ppt, mid salinity ranged 24.0 – 29.9 ppt, and bottom salinity ranged 28.2 – 30.7 ppt. Surface temperatures averaged 12.8°C and ranged from 10.7°C to 14.1°C. Mid temperatures averaged 13.4°C and ranged from 12.3°C to 14.3°C. Bottom temperatures averaged 14.2°C and ranged from 13.3°C to 14.8°C.

DO concentrations at Bullock Reach remained above the hypoxia threshold all week. Surface DO averaged 7.8 mg/L and ranged 6.8 – 9.5 mg/L. In the mid waters, DO averaged 7.3 mg/L and ranged 6.3 – 8.0 mg/L. At the bottom, DO averaged 6.7 mg/L and ranged 5.6 – 7.3 mg/L.  Chlorophyll concentrations were low, averaging 2.0 ug/L, 2.5 ug/L, and 2.1 ug/L at the surface, mid, and bottom waters, respectively. The maximum surface chlorophyll of 5.0 ug/L occurred during the afternoon on November 5th.​

Week of October 29 – November 4, 2023

Fixed Site Network

Phillipsdale Landing

Overall, water quality was good at Phillipsdale Landing this week. There were 1.14 inches of precipitation recorded at T.F. Green this week, mostly from rain events on the 29th and 30th. Blackstone River flow was higher than normal for this time of year. Surface salinity averaged 8.7 ppt and ranged from 2.0 ppt to 21.8 ppt. Bottom salinity averaged 20.5 ppt and ranged from 6.1 ppt to 27.9 ppt. Temperatures decreased this week, averaging 13.0°C at the surface and ranging from 8.8°C to 16.5°C. At the bottom, temperatures averaged 15.0°C and ranged from 11.2°C to 16.7°C.

Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold of 2.9 mg/L at both the surface and bottom. Surface DO remained similar to the previous week, averaging 8.7 mg/L and ranging from 5.6 to 11.1 mg/L. Bottom DO averaged 5.9 mg/L and ranged from 4.6 mg/L to 10.0 mg/L. Chlorophyll readings remained low, averaging 0.9 ug/L at the surface and 0.8 ug/L at the bottom. Maximum chlorophyll at the surface was only 3.5 ug/L, recorded on the morning of October 29th. . Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location. 

Bullock Reach 

Sondes were swapped this week on the morning of October 31. Overall, water quality was good at Bullock Reach this week. Salinity averaged 23.9 ppt, 27.3 ppt, and 29.4 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 20.4 – 27.5 ppt, mid salinity ranged 23.0 – 29.3 ppt, and bottom salinity ranged 27.8 – 30.4 ppt. Surface temperature averaged 14.3°C and ranged from 11.6°C to 17.0°C. Mid temperatures averaged 15.2°C and ranged from 13.6°C to 16.8°C. Bottom temperatures averaged 15.6°C and ranged from 13.9°C to 16.2°C.

DO concentrations at Bullock Reach remained above the hypoxia threshold all week. Surface DO averaged 7.3 mg/L and ranged 6.2 – 8.9 mg/L. In the mid waters, DO averaged 6.8 mg/L and ranged 5.8 – 9.5 mg/L. At the bottom, DO averaged 6.5 mg/L and ranged 5.9 – 7.2 mg/L.  Chlorophyll concentrations were low, averaging 1.9 ug/L, 2.5 ug/L, and 1.6 ug/L at the surface, mid, and bottom waters, respectively. The maximum surface chlorophyll of 4.7 ug/L occurred during the afternoon on November 4th.​

Newer Posts
Older Posts