Walkers Point
Overall, the water quality at Walkers Point was good to fair this week. Weather conditions were wet this week, with 2.33 inches of precipitation recorded at T.F. Green. Surface salinity averaged 16.9 ppt and ranged from 4.5 ppt to 27.4 ppt. At the bottom, salinity averaged 27.4 ppt and ranged from 23.5 ppt to 30.3 ppt. Temperatures averaged 24.0°C at the surface and 22.2°C at the bottom. Surface temperatures ranged from 21.5°C to 27.6°C, while bottom temperatures ranged from 20.7°C to 24.2°C.
Dissolved oxygen (DO) at Walkers Point remained above the hypoxia threshold (i.e., DO>2.9mg/L) at the surface but dropped below at the bottom depth. The longest periods of hypoxic conditions spanned 21 hours and 46 minutes, occurring at the bottom depth on the night of July 8th to the morning of July 9th. During this period, the DO averaged around 1.91 mg/L. Surface DO averaged 8.6 mg/L and ranged from 3.3 mg/L to 19.1 mg/L. Bottom DO concentrations averaged 2.3 mg/L and ranged from 0.1 mg/L to 4.5 mg/L. Chlorophyll readings averaged 14.5 µg/L at the surface and 4.6 µg/L at the bottom. Maximum chlorophyll at the surface reached 142.4 µg/L on the afternoon of July 7th.
Bullock Reach
Sondes were swapped this week on the morning of July 7th. Overall, water quality was good to fair at Bullock Reach this week. Salinity averaged 27.8 ppt, 29.9 ppt, and 31.8 ppt at the surface, middle, and bottom sondes, respectively. Surface salinity ranged 24.0 – 30.2 ppt, middle salinity range 27.0 – 31.7 ppt, and bottom salinity ranged 30.5 – 32.8 ppt. Surface temperature averaged 23.7°C and ranged from 21.5°C to 25.8°C. Middle temperature averaged 22.7°C and ranged from 19.8°C to 24.4°C. Bottom temperatures averaged 20.7°C and ranged from 18.7°C to 23.1°C.
Dissolved oxygen (DO) at Bullock Reach remained above the hypoxia threshold (i.e., DO>2.9mg/L) at the surface and middle depths, but dropped below the hypoxia threshold at the bottom depth. The longest period of hypoxic conditions at the bottom depth spanned 5 hours and 15 minutes, occurring on the night of July 6th to the morning of July 7th. During this period, the bottom DO averaged around 2.64 mg/L. Surface DO averaged 7.7 mg/L and ranged 4.7 – 13.3 mg/L. Middle DO averaged 6.0 mg/L and ranged 3.7 – 8.5 mg/L. At the bottom, DO averaged 4.2 mg/L and ranged 2.1 – 6.6 mg/L. Chlorophyll readings ranged from low to elevated throughout the week. Readings averaged 11.5 µg/L at the surface, 14.4 µg/L at the middle, and 10.1 µg/L at the bottom. The maximum surface chlorophyll was 24.6 µg/L on the night of July 10th.