An evaluation of the performance of Sea-Bird Scientific's SeaFET ? autonomous pH sensor: considerations for the broader oceanographic community

摘要

The commercially available Sea-Bird SeaFETsup?/sup provides an accessible way for a broad community of researchers to study ocean acidification and obtain robust measurements of seawater pH via the use of an in?situ autonomous sensor. There are pitfalls, however, that have been detailed in previous best practices for sensor care, deployment, and data handling. Here, we took advantage of two distinctly different coastal settings to evaluate the Sea-Bird SeaFETsup?/sup and examine the multitude of scenarios in which problems may arise confounding the accuracy of measured pH. High-resolution temporal measurements of pH were obtained during 3- to 5-month field deployments in three separate locations (two in south-central Alaska, USA, and one in British Columbia, Canada) spanning a broad range of nearshore temperature and salinity conditions. Both the internal and external electrodes onboard the SeaFETsup?/sup were evaluated against robust benchtop measurements for accuracy using the factory calibration, an in?situ single-point calibration, or an in?situ multi-point calibration. In addition, two sensors deployed in parallel in Kasitsna Bay, Alaska, USA, were compared for inter-sensor variability in order to quantify other factors contributing to the sensor's intrinsic inaccuracies. Based on our results, the multi-point calibration method provided the highest accuracy (?/sup electrodes.