Simulated effects of interactions between ocean acidification, marine organism calcification, and organic carbon export on ocean carbon and oxygen cycles
Ocean acidification caused by oceanic uptake of anthropogenic carbon dioxide (CO2) tends to suppress the calcification of some marine organisms. This reduced calcification then enhances surface ocean alkalinity and increases oceanic CO2 uptake, a process that is termed calcification feedback. On the other hand, decreased calcification also reduces the export flux of calcium carbonate (CaCO3), potentially reducing CaCO3-bound organic carbon export flux and CO2 uptake, a process that is termed ballast feedback. In this study, we incorporate a range of different parameterizations of the links between organic carbon export, calcification, and ocean acidification into an Earth system model, in order to quantify the long-term effects on oceanic CO2 uptake that result from calcification and ballast feedbacks. We utilize an intensive CO2 emission scenario to drive the model in which an estimated fossil fuel resource of 5000 Pg C is burnt out over the course of just a few centuries. Simulated results show that, in the absence of both calcification and ballast feedbacks, by year 3500, accumulated oceanic CO2 uptake is 2041 Pg C. Inclusion of calcification feedback alone increases the simulated uptake by 629 Pg C (31%), while the inclusion of both calcification and ballast feedbacks increase simulated uptake by 449–498 Pg C (22–24%), depending on the parameter values used in the ballast feedback scheme. These results indicate that ballast effect counteracts calcification effect in oceanic CO2 uptake. Ballast effect causes more organic carbon to accumulate and decompose in the upper ocean, which in turn leads to decreased oxygen concentration in the upper ocean and increased oxygen at depths. By year 2600, the inclusion of ballast effect would decrease oxygen concentration by 11% at depth of ca. 200 m in tropics. Our study highlights the potentially critical effects of interactions between ocean acidification, marine organism calcification, and CaCO3-bound organic carbon export on the ocean carbon and oxygen cycles.
KeywordsOcean carbon cycle Ocean acidification Carbon cycle modeling Carbon cycle-climate feedback
Unable to display preview. Download preview PDF.
This study was supported by the National Natural Science Foundation of China (Grant Nos. 41675063, 41422503 & 41276073), the National Key Basic Research Program of China (Grant No. 2015CB953601), and the Fundamental Research Funds for the Central Universities.
- Ciais P, Sabine C, Bala G, Bopp L, Brovkin V, Canadell J, Chhabra A. 2013. Carbon and other biogeochemical cycles. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate ChangeGoogle Scholar
- Cox P M. 2001. Description of the “TRIFFID” dynamic global vegetation model. Hadley Centre technical note, 24: 1–16Google Scholar
- Emerson S, Bender M. 1981. Carbon fluxes at the sediment-water interface of the deep-sea: Calcium-carbonate preservation. J Mar Res, 39: 139–162Google Scholar
- Friedlingstein P, Cox P, Betts R, Bopp L, von Bloh W, Brovkin V, Cadule P, Doney S, Eby M, Fung I, Bala G, John J, Jones C, Joos F, Kato T, Kawamiya M, Knorr W, Lindsay K, Matthews H D, Raddatz T, Rayner P, Reick C, Roeckner E, Schnitzler K G, Schnur R, Strassmann K, Weaver A J, Yoshikawa C, Zeng N. 2006. Climate-carbon cycle feedback analysis: Results from the C4 MIP model intercomparison. J Clim, 19: 3337–3353CrossRefGoogle Scholar
- Gregory J M, Dixon K W, Stouffer R J, Weaver A J, Driesschaert E, Eby M, Fichefet T, Hasumi H, Hu A, Jungclaus J H, Kamenkovich I V, Levermann A, Montoya M, Murakami S, Nawrath S, Oka A, Sokolov A P, Thorpe R B. 2005. A model intercomparison of changes in the Atlantic thermohaline circulation in response to increasing atmospheric CO2 concentration. Geophys Res Lett, 32: L12703CrossRefGoogle Scholar
- Jin X, Gruber N, Dunne J P, Sarmiento J L, Armstrong R A. 2006. Diagnosing the contribution of phytoplankton functional groups to the production and export of particulate organic carbon, CaCO3, and opal from global nutrient and alkalinity distributions. Glob Biogeochem Cycle, 20: GB2015CrossRefGoogle Scholar
- Najjar R G, Jin X, Louanchi F, Aumont O, Caldeira K, Doney S C, Dutay J C, Follows M, Gruber N, Joos F, Lindsay K, Maier-Reimer E, Matear R J, Matsumoto K, Monfray P, Mouchet A, Orr J C, Plattner G K, Sarmiento J L, Schlitzer R, Slater R D, Weirig M F, Yamanaka Y, Yool A. 2007. Impact of circulation on export production, dissolved organic matter, and dissolved oxygen in the ocean: Results from Phase II of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2). Glob Biogeochem Cycle, 21: GB3007CrossRefGoogle Scholar
- Orr J C, Najjar R, Sabine C L, Joos F. 1999. Design of OCMIP-2 simulations of chlorofluorocarbons, the solubility pump and common biogeochemistry. Internal OCMIP ReportGoogle Scholar
- Pachauri R K, Meyer L A, Barros V R, Broome J, Cramer W, Christ R. 2014. Synthesis report: Summary for policymakers. In: Pachauri R K, Meyer L A, eds. Climate Change 2014: Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Geneva, 4Google Scholar
- Plattner G K, Joos F, Stocker T F, Marchal O. 2001. Feedback mechanisms and sensitivities of ocean carbon uptake under global warming. Tellus B, 53: 564–592Google Scholar
- Sarmiento J L, Gruber N. 2006. Ocean Biogeochemical Dynamics. Princeton and Oxford: Princeton University Press. 73–394Google Scholar
- Schneider B, Bopp L, Gehlen M, Segschneider J, Frölicher T L, Cadule P, Friedlingstein P, Doney S C, Behrenfeld M J, Joos F. 2008. Climateinduced interannual variability of marine primary and export production in three global coupled climate carbon cycle models. Biogeosciences, 5: 597–614CrossRefGoogle Scholar
- Stouffer R J, Yin J, Gregory J M, Dixon K W, Spelman M J, Hurlin W, Weaver A J, Eby M, Flato G M, Hasumi H, Hu A, Jungclaus J H, Kamenkovich I V, Levermann A, Montoya M, Murakami S, Nawrath S, Oka A, Peltier W R, Robitaille D Y, Sokolov A, Vettoretti G, Weber S L. 2006. Investigating the causes of the response of the thermohaline circulation to past and future climate changes. J Clim, 19: 1365–1387CrossRefGoogle Scholar
- Takahashi T, Sutherland S C, Wanninkhof R, Sweeney C, Feely R A, Chipman D W, Hales B, Friederich G, Chavez F, Sabine C, Watson A, Bakker D C E, Schuster U, Metzl N, Yoshikawa-Inoue H, Ishii M, Midorikawa T, Nojiri Y, Körtzinger A, Steinhoff T, Hoppema M, Olafsson J, Arnarson T S, Tilbrook B, Johannessen T, Olsen A, Bellerby R, Wong C S, Delille B, Bates N R, de Baar H J W. 2009. Climatological mean and decadal change in surface ocean pCO2, and net sea-air CO2 flux over the global oceans. Deep-Sea Res Part II-Top Stud Oceanogr, 56: 554–577CrossRefGoogle Scholar
- Weaver A J, Eby M, Wiebe E C, Bitz C M, Duffy P B, Ewen T L, Fanning A F, Holland M M, MacFadyen A, Matthews H D, Meissner K J, Saenko O, Schmittner A, Wang H, Yoshimori M. 2001. The UVic earth system climate model: Model description, climatology, and applications to past, present and future climates. Atmosphere-Ocean, 39: 361–428CrossRefGoogle Scholar
- Zickfeld K, Eby M, Weaver A J, Alexander K, Crespin E, Edwards N R, Eliseev AV, Feulner G, Fichefet T, Forest C E, Friedlingstein P, Goosse H, Holden P B, Joos F, Kawamiya M, Kicklighter D, Kienert H, Matsumoto K, Mokhov I I, Monier E, Olsen S M, Pedersen J O P, Perrette M, Philippon-Berthier G, Ridgwell A, Schlosser A, Schneider Von Deimling T, Shaffer G, Sokolov A, Spahni R, Steinacher M, Tachiiri K, Tokos K S, Yoshimori M, Zeng N, Zhao F. 2013. Long-term climate change commitment and reversibility: An EMIC intercomparison. J Clim, 26: 5782–5809CrossRefGoogle Scholar