Phillipsdale Landing
Overall, water quality at Phillipsdale Landing was good this week. Weather conditions were mostly dry, with just trace rainfall on January 29th and February 1st, and minor snowfall on January 31st. Blackstone River flows declined over the course of the week. Surface salinity averaged 1.7 ppt and ranged from 0.2 ppt to 7.7 ppt. At the bottom, salinity averaged 11.4 ppt and ranged from 0.3 ppt to 29.7 ppt. February 3rd and 4th saw a blast of arctic air temperatures, and the waters responded by cooling dramatically at the end of the week. Temperatures overall averaged 4.0°C at the surface, ranging -0.3°C – 6.5°C. At the bottom, temperatures averaged 4.4°C and ranged 0.0°C – 6.0°C. During the cold snap, the surface sonde went out of position, possibly due to ice formation impacting sonde buoyancy; approximately 19 hours of surface data were excluded from this summary when the sonde was out of position.
Dissolved oxygen (DO) at Phillipsdale Landing remained above the hypoxia threshold of 2.9 mg/L throughout the week. Surface DO averaged 12.9 mg/L and ranged 12.0 – 14.8 mg/L. Bottom DO concentrations averaged 11.8 mg/L and ranged from 8.4 mg/L to 14.2 mg/L. Chlorophyll readings remained low, averaging 2.0 ug/L at the surface and 9.9 ug/L at the bottom. Maximum chlorophyll at the surface reached just 8.4 ug/L this week. Chlorophyll at the bottom was elevated late in the week, though this does not appear to be related to phytoplankton activity as there were no concurrent changes to pH or DO; the spikes may have been related to the very cold temperatures or sediment interference. Please note that tidal fluctuations and Blackstone River flows greatly influence water column salinity, temperature, and DO at this location.
Bullock Reach
Bullock Reach sondes will be deployed later this spring for the 2023 monitoring season.