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Radiocarbon in the Maritime Air and Sea Surface Water of the South China Sea

Published online by Cambridge University Press:  05 December 2018

Pan Gao Open the ORCID record for Pan Gao [Opens in a new window] ,
Liping Zhou ,
Kexin Liu  and
Xiaomei Xu
Pan Gao*
Affiliation:
Key Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871, China
Liping Zhou*
Affiliation:
Key Laboratory for Earth Surface Processes, Department of Geography, Peking University, Beijing 100871, China Institute of Ocean Research, Peking University, Beijing 100871, China Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China
Kexin Liu
Affiliation:
Institute of Heavy Ion Physics & State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871, China
Xiaomei Xu
Affiliation:
Keck Carbon Cycle AMS Laboratory, Department of Earth System Science, University of California, Irvine, CA 92697-3100, USA
*
*Corresponding authors. Emails: pangao@pku.edu.cn; lpzhou@pku.edu.cn.
*Corresponding authors. Emails: pangao@pku.edu.cn; lpzhou@pku.edu.cn.
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Abstract

Radiocarbon (14C) generated by the thermonuclear tests in the late 1950s to early 1960s has been used as a tracer to study atmospheric and oceanic circulations, carbon exchange between different reservoirs, and fossil fuel emissions. Here we report the first measurements of 14C in atmospheric CO2 of maritime air collected over the South China Sea (SCS) during July 2014. We also present 14C of the dissolved inorganic carbon (DIC) in the sea surface water in the same region. Most of the Δ14C values of the atmospheric CO2 vary in the range of 15.6±1.6‰– 22.0±1.6‰, indicating that the central SCS maritime air is well-mixed and consistent with the clean background air in the Northern Hemisphere. The 14C values of the DIC (DI14C) in the surface seawater vary between 28.3±2.5‰ and 40.6±2.7‰, mainly due to the lateral mixing between the SCS and western Pacific. The average surface seawater DI14C is 15.4 ± 5.1‰ higher than that of the maritime air 14CO2. The reversal of the sea–air Δ14C gradient occurred at ∼2000, marking the start of the upper ocean transferring bomb 14C back to the atmosphere in the SCS.

Keywords

Δ14Cbomb radiocarbondissolved inorganic carbonmaritime air CO2South China Sea
Type
Research Article
Information
Radiocarbon , Volume 61 , Issue 2 , April 2019 , pp. 461 - 472
Copyright
© 2018 by the Arizona Board of Regents on behalf of the University of Arizona 

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References

REFERENCES

Alves, EQ, Macario, K, Ascough, P, Bronk Ramsey, C. 2018. The worldwide marine radiocarbon reservoir effect: definitions, mechanisms, and prospects. Reviews of Geophysics 56:278–305.Google Scholar
Bhushan, R, Krishnaswami, S, Somayajulu, BLK. 1997. 14C in air over the Arabian Sea. Current Science 73(3):273–276.Google Scholar
Broecker, WS, Peng, TH. 1974. Gas exchange between air and sea. Tellus 26(1–2):21–35.Google Scholar
Broecker, WS, Peng, TH, Ostlund, G, Stuiver, M. 1985. The distribution of bomb radiocarbon in the ocean. Journal of Geophysical Research 90:6953–6970.Google Scholar
Broecker, WS, Patzert, WC, Toggweiler, JR, Stuiver, M. 1986. Hydrography, chemistry, and radioisotopes in the Southeast Asian basins. Journal of Geophysical Research Oceans 91(C12):14345–14354.Google Scholar
Caldeira, K, Rau, GH, Duffy, PB. 1998. Predicted net efflux of radiocarbon from the ocean and increase in atmospheric radiocarbon content. Geophysical Research Letters 25(20):3811–3814.Google Scholar
Centurioni, LR, Niiler, PP, Lee, D K. 2004. Observations of Inflow of Philippine Sea Surface Water into the South China Sea through the Luzon Strait. Journal of Physical Oceanography 34:113–121.Google Scholar
Dai, M, Cao, Z, Guo, X, Zhai, W, Liu, Z, Yin, Z, Xu, Y, Gan, J, Hu, J, Du, C. 2013. Why are some marginal seas sources of atmospheric CO2? Geophysical Research Letters 40(10):2154–2158.Google Scholar
Draxler, RR, Rolph, GD. 2013. HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY Website (http://www.arl.noaa.gov/HYSPLIT.php). NOAA Air Resources Laboratory, College Park, MD.Google Scholar
Druffel, ERM, Suess, HE. 1983. On the radiocarbon record in banded corals: Exchange parameters and net transport of 14CO2, between atmosphere and surface ocean. Journal of Geophysical Research Oceans 88(C2):1271–1280.Google Scholar
Druffel, ERM, Griffin, S. 1995. Regional variability of surface ocean radiocarbon from southern Great Barrier Reef corals. Radiocarbon 37(2):517–524.Google Scholar
Dutta, K. 2002. Coherence of tropospheric 14CO2 with El Niño/Southern Oscillation. Geophysical Research Letters 29(20):1987.Google Scholar
Dutta, K, Bhushan, R, Somayajulu, BLK, Rastogi, N. 2006. Inter-annual variation in atmospheric Δ14C over the Northern Indian Ocean. Atmospheric Environment 40(24):4501–4512.Google Scholar
Fang, G, Wang, Y, Wei, Z, Fang, Y, Qiao, F, Hu, X, 2009. Interocean circulation and heat and freshwater budgets of the South China Sea based on a numerical model. Dynamics of Atmospheres and Oceans 47:55–72.Google Scholar
Gan, J, Li, H, Curchitser, EN, Haidvogel, DB. 2006. Modeling South China Sea circulation Response to seasonal forcing regimes. Journal of Geophysical Research 111:C06034.Google Scholar
Gao, P, Xu, X, Zhou, L, Pack, MA, Griffin, S, Santos, GM, Southon, JR, Liu, K. 2014. Rapid sample preparation of dissolved inorganic carbon in natural waters using a headspace-extraction approach for radiocarbon analysis by accelerator mass spectrometry. Limnology & Oceanography Methods 12(4):174–190.Google Scholar
Graven, HD, Gruber, N, Key, RM, Khatiwala, S, Giraud, X. 2012. Changing controls on oceanic radiocarbon: New insights on shallow-to-deep ocean exchange and anthropogenic CO2 uptake. Journal of Geophysical Research Oceans 117(C10): 005.Google Scholar
Hammer, S, Levin, I. 2017. Monthly mean atmospheric D14CO2 at Jungfraujoch and Schauinsland from 1986 to 2016. heiDATA Dataverse, V2. doi:10.11588/data/10100.Google Scholar
Hsin, YC, Wu, CR, Chao, SY. 2012. An updated examination of the Luzon Strait transport. Journal of Geophysical Research Oceans 117: C03022.Google Scholar
Key, RM, Kozyr, A, Sabine, CL, Lee, K, Wanninkhof, R, Bullister, JL, Feely, RA, Millero, FJ, Mordy, C, Peng, TH. 2004. A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Global Biogeochemical Cycles 18(4):357–370.Google Scholar
Kitagawa, H, Mukai, H, Nojiri, Y, Shibata, Y, Kobayashi, T, Nojiri, T. 2004. Seasonal and secular variations of atmospheric 14CO2 over the Western Pacific since 1994. Radiocarbon 46(2):901–910.Google Scholar
Köhler, P. 2016. Using the Suess effect on the stable carbon isotope to distinguish the future from the past in radiocarbon. Environmental Research Letters 11:124016.Google Scholar
Krakauer, NY, Randerson, JT, Primeau, FW, Gruber, N, Menemenlis, D. 2006. Carbon isotope evidence for the latitudinal distribution and wind speed dependence of the air–sea gas transfer velocity. Tellus B: Chemical & Physical Meteorology 58(5):390–417.Google Scholar
Levin, I, Kromer, B. 2004. The Tropospheric 14CO2 level in mid-latitudes of the Northern Hemisphere (1959–2003). Radiocarbon 46(3):1261–1272.Google Scholar
Levin, I, Naegler, T, Kromer, B, Diehl, M, Francey, RJ, Gomez-Pelaez, AJ, Steele, LP, Wagenbach, D, Weller, R, Worthy, DE. 2010. Observations and modelling of the global distribution and long-term trend of atmospheric 14CO2 . Tellus B 62(1): 26–46.Google Scholar
Levin, I, Kromer, B, Hammer, S. 2013. Atmospheric Δ14CO2 trend in Western European background air from 2000 to 2012. Tellus B: Chemical & Physical Meteorology 65(1):20092.Google Scholar
Li, L, Qu, T. 2006. Thermohaline circulation in the deep South China Sea basin inferred from oxygen distributions. Journal of Geophysical Research Oceans 111(C05):017.Google Scholar
Liu, K, Ding, X, Fu, D, Pan, Y, Wu, X, Guo, Z, Zhou, L. 2007. A new compact AMS system at Peking University. Nuclear Instruments & Methods in Physics Research 259(1):23–26.Google Scholar
Nan, F, Xue, H, Yu, F. 2015. Kuroshio intrusion into the South China Sea: A review. Progress in Oceanography 137:314–333.Google Scholar
Qu, T. 2000a. Upper-layer circulation in the South China Sea. Journal of Physical Oceanography 30:1450–1460.Google Scholar
Qu, T, Mitsudera, H, Yamagata, T. 2000b. Intrusion of the North Pacific waters into the South China Sea. Journal of Geophysical Research 105(C3):6415–6424.Google Scholar
Qu, T. 2002. Evidence of water exchange between the South China Sea and the Pacific through the Luzon Strait. Acta Oceanologica Sinica 21(2):175–185.Google Scholar
Reimer, PJ, Thomas, AB, Reimer, RW. 2004. Discussion: reporting and calibration of post-bomb 14C data. Radiocarbon 46(3):1299–1304.Google Scholar
Shaw, PT, Chao, SY. 1994. Surface circulation in the South China Sea. Deep-Sea Research I 41:1663–1683.Google Scholar
Su, J. 2004. Overview of the South China Sea circulation and its influence on the coastal physical oceanography outside the Pearl River Estuary. Continental Shelf Research 24:1745–1760.Google Scholar
Suess, HE. 1955. Radiocarbon concentration in modern wood. Science 122(3166):415–417.Google Scholar
Sweeney, C, Gloor, E, Jacobson, AR, Key, RM, McKinley, G, Sarmiento, JL, Wanninkhof, R. 2007. Constraining global air–sea gas exchange for CO2 with recent bomb 14C measurements. Global Biogeochemical Cycles 21:GB2015.Google Scholar
Tian, J, Yang, Q, Liang, X, Xie, L, Hu, D, Wang, F, Qu, T. 2006. Observation of Luzon Strait transport. Geophysical Research Letters 33:L19607.Google Scholar
Tian, J, Yang, Q, Zhao, W. 2009. Observation of enhanced diapycnal mixing in the South China Sea. Journal of Physical Oceanography 39(12):3191–3203.Google Scholar
Toggweiler, JR, Dixon, K, Bryan, K. 1989. Simulations of radiocarbon in a coarse-resolution world ocean model: 1. Steady state prebomb distributions. Journal of Geophysical Research Oceans 94(C6):8217–8242.Google Scholar
Turnbull, JC, Lehman, SJ, Miller, JB, Sparks, RJ, Southon, JR, Tans, PP. 2007. A new high precision 14CO2 time series for North American continental air. Journal of Geophysical Research Atmospheres 112(D11):310.Google Scholar
Wyrtki, K. 1961. Physical Oceanography of the Southeast Asian Waters. Naga Report 2. La Jolla, California: Scripps Institute of Oceanography, University of California, San Diego. 195 p.Google Scholar
Xu, X, Trumbore, SE, Zheng, S, Southon, JR, McDuffe, KE, Luttgen, M, Liu, JC. 2007. Modifying a sealed tube zinc reduction method for preparation of AMS graphite targets: Reducing background and attaining high precision. Nuclear Instruments and Methods in Physics Research 259(1):320–329.Google Scholar
Yang, Q, Tian, J, Zhao, W. 2010. Observation of Luzon Strait transport in Summer 2007. Deep-Sea Research Ι 57(5):670–676.Google Scholar
Zhai, W, Dai, M, Chen, B, Guo, X, Li, Q, Shang, S, Zhang, C, Cai, W, Wang, D. 2013. Seasonal variations of air–sea CO2 fluxes in the largest tropical marginal sea (South China Sea) based on multiple-year underway measurements. Biogeosciences 10(11):7775–7791.Google Scholar
Zhang, Z, Tian, J, Qiu, B, Zhao, W, Chang, P, Wu, D, Wan, X. 2016. Observed 3D structure, generation, and dissipation of oceanic mesoscale eddies in the South China Sea. Scientific Reports 6:24349.Google Scholar