The exchange of carbon dioxide between the atmosphere and the ocean is partly dependent on the difference in the CO2 concentration between the surface water and the overlying air. As the atmospheric concentration changes so, too, does the flux into and out of the ocean. When CO2 from the atmosphere dissolves in seawater a series of reactions takes place involving bicarbonate and carbonate ions, as well as hydrogen ions (measure on the pH scale) and solid carbonate. The concentration of CO2 in seawater depends on several factors, including water temperature, biological activity and deep-water upwelling. These factors vary over space and time, so the seawater CO2 concentration also varies between different ocean sites, and in different seasons.
Kim has been looking at the CO2 chemistry of the waters off the coast of Otago since 1998, using a time series approach. Over the past 14 years she has been making careful measurements of CO2 species and other related parameters to try and understand the changes that occur in these waters – seasonally, from year to year, and over the long-term.
More information can be found on Kim’s webpage.
Currie, K.I., Reid, M.R., and Hunter, K.A. (2011). Interannual variability of carbon dioxide drawdown by subantarctic surface water near New Zealand. Biogeochemistry, 104(1-3): 23-34.
Currie, K.I., Macaskill, B., Reid, M.R., and Law, C.S. (2011). Processes governing the carbon chemistry during the SAGE experiment. Deep-Sea Research II, 58(6): 851-860.
Cummings, V., Hewitt, J., Van Rooyen, A., Currie, K., Beard, S., Thrush, S., Norkko, J., Barr, N., Heath, P., Halliday, N.J., Sedcole, R., Gomez, A., McGraw, C., and Metcalf, V. (2011). Ocean acidification at high latitudes: potential effects on functioning of the Antarctic bivalve Laternula elliptica. PLoS ONE 6 (1), e16069. doi:10.1371/journal.pone.0016069.
McGraw, C.M., Cornwall, C., Reid, M.R., Currie, K.I., Hepburn, C., Boyd, P.W., Hurd, C., Hunter, K.A. (2010). An automated pH-controlled culture system for laboratory-based ocean acidification experiments. Limnology and Oceanography: Methods, 8: 686-694.