R/V Monitor's Blog
On Thursday, October 1st, the crew of the R/V Monitor was out on the upper Bay collecting bacteria samples, taking Secchi Disk and Par sensor water clarity measurements, conducting water column profiles using the Seabird instrument, and conducting real-time surface mapping of water quality parameters, including dissolved oxygen, chlorophyll, water temperature, salinity, and pH, all in an effort to document water quality improvements associated with NBC construction projects. The crew also serviced the temporary buoy located in Pawtuxet Cove, and changed out the sonde with a freshly calibrated instrument. Sara captained the boat while monitoring professionals Steve and Daryll collected the samples and data. The day started partly cloudy but turned to full sun by the afternoon. There was a wind out of the southwest all day, making for a heavy chop on the water. The photo taken this day was taken from inside the hurricane barrier.
Water Column Clarity
Water clarity was measured at eight locations in the Providence and Seekonk Rivers on September 23, 2020. No rainfall was recorded on the day of the survey and in the three days prior. Water clarity increased slightly compared to the previous survey day. Overall, sites surveyed averaged 1.88 meters Secchi depth, compared to 1.69 meters on September 16. The lowest clarity (1.10 meters) was measured at the Phillipsdale Landing site, while the greatest clarity (2.30 meters) was measured at the Bullock's Reach site. Overall, a slight gradient of increasing clarity from north to south was observed among all sites.
Fixed Site Network
Water quality was good this week at Phillipsdale Landing. No precipitation was recorded over the course of the week. Compared to last week, average water column salinity has increased, and water temperatures have decreased. Surface salinity averaged 24.7 ppt and ranged from 21.0 ppt to 28.0 ppt. Bottom salinity averaged 26.6 ppt and ranged from 23.1 ppt to 29.2 ppt. Surface and bottom water temperatures averaged 18.3°C and 18.5°C, respectively. Surface temperatures ranged from 15.7°C to 21.0°C, while bottom temperatures ranged from 18.5°C to 20.7°C.
Dissolved oxygen (DO) remained above the hypoxia threshold (2.9) in surface and bottom waters this week. Surface DO averaged 9.4 mg/L, with a minimum of 5.5 mg/L, and bottom DO averaged 7.5 mg/L, with a minimum of 5.0 mg/L. Chlorophyll concentrations have remained elevated; surface chlorophyll averaged 44.0 ug/L and bottom chlorophyll averaged 36.6 ug/L; maximum chlorophyll concentrations of over 75 ug/L were recorded at both depths. Please note that tidal fluctuations and Blackstone River flow greatly influence water column salinity, temperature, and dissolved oxygen at this location.
Water quality was good this week at Bullock Reach. Sondes were changed out for routine maintenance during the morning of September 23. Salinity was slightly higher at all three depths this week compared to last week. Surface salinity averaged 29.8 ppt and ranged from 29.1 ppt to 30.6 ppt. Salinity at the mid depth averaged 30.3 ppt and ranged from 29.7 ppt to 31.1 ppt, while salinity in bottom waters averaged 31.3 ppt and ranged from 30.2 ppt to 31.9 ppt. Temperatures at Bullock Reach continue to cool, averaging 18.3°C, 18.1°C, and 17.9°C at the surface, middle, and bottom of the water column, respectively. Surface temperatures ranged from 16.5°C to 19.6°C, mid temperatures ranged from 16.8°C to 22.6°C, and bottom temperatures ranged from 17.0°C to 19.5°C.
Dissolved oxygen (DO) concentrations remained above the hypoxia threshold (2.9 mg/L) throughout the water column. Surface, middle, and bottom DO averaged 7.8 mg/L, 7.5 mg/L and 7.0 mg/L, respectively. Minimum DO concentration was 5.7 mg/L, measured in bottom waters on September 26th. Chlorophyll concentrations declined over the course of the week. Surface chlorophyll averaged 7.2 ug/L, mid chlorophyll averaged 6.7 ug/L, and bottom chlorophyll averaged 6.9 ug/L, with a maximum concentration of 20 ug/L observed in bottom waters.
were collected on September 23, 2020 while the R/V Monitor was underway
collecting nutrient samples and performing vertical profiles in the Providence
and Seekonk River estuaries. The chlorophyll concentrations were good to fair
in the areas surveyed with slightly elevated results in the northernmost
sampled areas. From north to south, average chlorophyll concentrations were as
follows: Seekonk River (12.19 µg/L), Upper Providence River (4.47 µg/L),
Edgewood Shoals area (4.57 µg/L), Pawtuxet River area (6.26 µg/L), and Lower Providence
River area (5.49 µg/L). Overall, chlorophyll ranged between 2.20 µg/L and 29.00
µg/L with an overall average of 6.24 µg/L. The chlorophyll data from this
date are presented in the map below:
R/V Monitor's Blog
The R/V Monitor was out on the boat twice this week. First, on Wednesday, September 23rd, the crew was out collecting nutrients and plankton samples, taking Secchi Disk and Par sensor water clarity measurements, conducting water column profiles using the Seabird instrument, and conducting real-time surface mapping of water quality parameters, including dissolved oxygen, chlorophyll, water temperature, salinity, and pH, all in an effort to document water quality improvenents associated with NBC construction projects. In addition, the Bullock's Reach buoy was serviced and sondes changed out. Jeff captained the boat while monitoring professionals Gerard and Mike collected the samples and data, and serviced the buoy. It was a cool, crisp, sunny morning warming up nicely by the afteroon. There was a light wind from the west-northwest and calm waters all day. On Thursday, September 24th the crew returned to conduct benthic video transects at established sites in the Bay. It was a warm, cloudy day with a light wind out of the south and calm waters. Jeff captained the boat while monitoring professionals Gerard and Amanda conducted the video transects. This week's photo was taken on Wednesday and features a US Coast Guard ship out on the upper Bay.