USAP-DC

The proposed project will expand the suite of observations and lengthen the existing time series of underway surface dissolved carbon dioxide (pCO2) measurements transects across the Drake Passage on the R/VIB L.M. Gould. The additional observations include oxygen, nutrients and total CO2 (TCO2) concentrations, and the 13C to 12C ratio of TCO2. The continued and expanded time series will contribute towards two main scientific goals: the quantification of the spatial and temporal variability and the trends of surface carbon dioxide species in four major water mass regimes in the Drake Passage, and the understanding of the dominant processes and changes in those processes that contribute to the variability in surface pCO2 and the resulting air-sea flux of CO2 in the Drake Passage. The expanded program will also include the analysis of the 14C/12C of TCO2 and the specific study of the observations on one short wintertime cruise, with the objective of testing the hypothesis that the dissolved carbon dioxide in surface waters of the Drake Passage is determined by the degree of winter mixing. This is of special significance in light of two scenarios that may be affecting the ventilation of Southern Ocean deep water now and in the future: a decrease in water column stratification with the observations of higher zonal winds, or an increase in stratification due to higher precipitation and warming from climate change. If winter mixing determines the mean annual pCO2 in the Drake Passage, the increasing trend in atmospheric pCO2 should have little effect on sea surface pCO2.

Person	Role
Sweeney, Colm	Investigator
Sweeney, Colm	Investigator

Antarctic Ocean and Atmospheric Sciences

Award # 0636975

Deployment	Type
LMG0909	ship expedition

None in the Database

Repository	Title (link)	Format(s)	Status
R2R	Expedition data of LMG0909	None	exists

1. Quay, P., Sonnerup, R., Munro, D., & Sweeney, C. (2017). Anthropogenic CO2accumulation and uptake rates in the Pacific Ocean based on changes in the13C/12C of dissolved inorganic carbon. Global Biogeochemical Cycles, 31(1), 59–80. (doi:10.1002/2016gb005460)
2. Landschützer, P., Gruber, N., Haumann, F. A., Rödenbeck, C., Bakker, D. C. E., van Heuven, S., … Wanninkhof, R. (2015). The reinvigoration of the Southern Ocean carbon sink. Science, 349(6253), 1221–1224. (doi:10.1126/science.aab2620)