In situ, continuous measurement of CO2 and pH in the near-surface water
In situ, continuous measurement of CO2 and pH in the near-surface water
The recently discovered dynamic exchange of carbon between the atmosphere, sea ice, and underlying marine water has shown the importance of a geochemical pump driven by sea ice formation and dissolution. The creation of sea ice brine (with elevated CO2 concentrations due to ice exclusion and carbonate precipitation) and its eventual vertical migration provides an efficient mechanism for transferring carbon into the deeper water column. In addition, this process results in CO2-undersaturated surface waters, leading to a greater flux of CO2 from the atmosphere to water once sea ice melt occurs. To better understand this transient system, multi-level pCO2 probes (4 sensors spaced 10cm apart) will be installed in the top 40 cm of the water column to continuously measure vertical pCO2 distribution and temperature once every minute. The sensors to be used are an updated version of the “GasPro” probes developed by the Università di Roma “La Sapienza“ and previously applied in various environments, including warm marine waters (doi: 10.1021/es500666u), unsaturated soils (doi: 10.1016/j.ijggc.2014.06.021), and groundwater wells. The multi-level probe will monitor the evolution of the carbonate system during freezing to help confirm the mechanisms causing the “C” shaped distribution of pH observed in previous SERF experiments (e.g., Hare et al., 2013) and to estimate brine rejection rates.
Fieldwork site: Sea Ice Environmental Research Facility (SERF), University of Manitoba, Winnipeg (Canada)
PI: S.Beaubien, T.Papakyriakou, F.Wang
Project Lead: S.Beaubien
Project Participants: Dr. Stan Beaubien, Stefano Graziani, Sabina Bigi (Università di Roma “La Sapienza“); Dr. Tim Papakyriakou (CEOS), Dr. Fei Wang (CEOS); Yubin Hu (CEOS); Marcos Lemes (CEOS)