Sondes at Bullock Reach were changed out for routine maintenance in the morning on June 29th. As noted last week, the bottom sonde deployed June 15-29, 2021 did not record data, so the summary below includes bottom data only from the partial week. Water quality at Bullock Reach was good-to-fair this week. Salinity at the surface averaged 24.2 ppt and ranged from 19.5 ppt to 27.7 ppt. Salinity at the mid depth averaged 27.4 ppt and ranged from 22.1 ppt to 30.8 ppt. Salinity in bottom waters averaged 30.3 ppt and ranged from 28.3 ppt to 31.8 ppt. Temperatures averaged 24.3°C, 23.0°C, and 20.0°C at the surface, mid, and bottom, respectively. Surface temperatures ranged from 20.0°C to 27.8°C, mid temperatures ranged from 19.7°C to 25.8°C, and bottom temperatures ranged 18.4°C to 21.9°C.
Dissolved oxygen (DO) data this week should be interpreted with caution due to a calibration issue with the sondes retrieved June 29th that resulted in the data biasing high. These data will be reviewed in detail at the end of the season and adjusted as necessary by the Narragansett Bay Fixed Site Monitoring Network. This week surface DO averaged 8.4 mg/L, while mid DO averaged 6.4 mg/L, and bottom DO averaged 4.4 mg/L. The minimum DO was recorded at the mid-depth as 2.9 mg/L on July 3rd. Chlorophyll concentrations remained slightly elevated, averaging 11.4 ug/L at the surface, 10.1 ug/L in mid-depth waters, and 4.1 ug/L at the bottom. The maximum water column chlorophyll concentration was 50.4 ug/L, measured in bottom waters on June 30th.