Dataset: Continuously monitored water quality measurements from five salt marsh ponds in New Jersey, USA from Apr 2023 to Jun 2024

Continuous water-quality monitoring was conducted in five salt marsh ponds (mean water depths <1m) located within SMIIL from April 2023–June 2024. Water quality sensors were mounted approximately 15 cm above the bottom of the pond to a fixed pole. Each pond was equipped with internally logging HOBO sensors (Onset Computer Corp.) that measured pressure, conductivity/salinity, dissolved oxygen (DO), and pH every 10 minutes. Temperature was also recorded by each of the sensors, and temperature data provided here reflects the median of the four sensors in each pond. An additional HOBO pressure sensor, deployed at a central location within SMIIL, recorded air temperature and barometric pressure. During maintenance trips every 4-16 weeks, sensors were retrieved, cleaned, recalibrated (DO and pH only) and redeployed in each pond for a total of five deployments. Data files from each sensor were downloaded during each maintenance visit. Discrete surface-water samples for DO, dissolved inorganic carbon (DIC), and total alkalinity (TA) measurements were also collected during maintenance visits and used to validate DO and pH time series data (see discrete sample dataset, also in this project).
 
HOBO DO loggers were calibrated every service trip before deployment using two points: a 100% saturation open air point and a 0% point using sodium sulfite dissolved in deionized water. HOBO pH loggers were calibrated every service trip before deployment using three-point calibration standards: pH 4.0, pH 7.0, and pH 10.0.