Dataset: Porewater geochemistry of sediments collected Fall 2019 in the Santa Barbara Basin using ROV Jason during R/V Atlantis cruise AT42-19

Sediments were collected with push cores (6 cm inner diameter) along three depth transects across the Santa Barbara Basin using the ROV Jason.  Porewater was separated from sediment by centrifugation (4300 x g for 20 mins) in anoxic centrifugation vials and subsampled for further analysis. 

Porewater geochemical properties were determined as listed:

• Porewater sulfate concentrations were determined by ion chromatography (Metrohm 761).
• Porewater sulfide concentrations were determined spectrophotometrically (Shimadzu UV-Spectrophotometer UV-1800) according to Cline (1969).
• Porewater ammonium, iron (II), and phosphate concentrations were determined spectrophotometrically (Shimadzu UV-Spectrophotometer UV-1800) according to Grasshoff et al. (1999).
• Porewater nitrate and nitrite concentrations were determined spectrophotometrically (Shimadzu UV-Spectrophotometer UV-1800) according to García-Robledo et al. (2014).
• Porewater Total Alkalinity was determined by titration according to Dale et al. 2015. Porewater Dissolved Inorganic Carbon was determined using a flow injection system (Hall & Aller 1992).

Note:  Negative depths refer to measurements in the sediment core supernatant water.  Supernatant water was collected with an anoxic syringe prior to core slicing.