Abstract
The South China Sea (SCS) is strongly influenced by the East Asian monsoon system with seasonal reversal. Measurements from a 7-year continuous sediment trap located in the central SCS showed a clear seasonal pattern. The particulate organic carbon (POC) export flux at the depth of 1200 m was considerably higher in monsoon seasons. The driving dynamics leading to this seasonal variability of POC export, however, remains inadequately understood. Here, a one-dimensional physical-biogeochemical coupled model was developed to simulate the temporal variability of a lower-trophic planktonic ecosystem. The modeled POC export flux compared reasonably well with the 7-year time series from moored sediment trap. Model results showed that the POC export flux at 1200 m is highly correlated with the 0–100 m integrated primary productivity and with the export flux at 100 m, implying that the seasonal variability of sediment trap data could be induced by changes in phytoplankton production and its vertical export. Further model analysis suggested that the annual mean export ratio (e-ratio) at 100 m and transfer efficiency at 1200 m in the central SCS were 0.19 and 0.07, respectively, which are lower than those in high latitudes. The winter monsoon favors not only surface carbon fixation but also export to the deep ocean. The heat flux is the dominant factor regulating the seasonal cycle of mixed layer depth, nutrient supply, and the growth of phytoplankton in this region. The wind-driven mixing can further facilitate upward nutrient transport to the surface and amplify the seasonal amplitude of the POC export flux.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Armstrong RA, Peterson ML, Lee C, Wakeham SG (2009) Settling velocity spectra and the ballast ratio hypothesis. Deep-Sea Res Pt II 56:1470–1478. https://doi.org/10.1016/j.dsr2.2008.11.032
Bach LT, Riebesell U, Sett S, Febiri S, Rzepka P, Schulz KG (2012) An approach for particle sinking velocity measurements in the 3–400 μm size range and considerations on the effect of temperature on sinking rates. Mar Biol 159:1853–1864. https://doi.org/10.1007/s00227-012-1945-2
Bach LT, Boxhammer T, Larsen A, Hildebrandt N, Schulz KG, Riebesell U (2016) Influence of plankton community structure on the sinking velocity of marine aggregates. Glob Biogeochem Cycles 30:1145–1165. https://doi.org/10.1002/2016GB005372
Behrenfeld MJ, Falkowski PG (1997) Photosynthetic rates derived from satellite-based chlorophyll concentration. Limnol Oceanogr 42:1–20. https://doi.org/10.4319/lo.1997.42.1.0001
Buesseler KO, Boyd PW (2009) Shedding light on processes that control particle export and flux attenuation in the twilight zone of the open ocean. Limnol Oceanogr 54:1210–1232. https://doi.org/10.4319/lo.2009.54.4.1210
Buesseler KO, Lamborg CH, Boyd PW, Lam PJ, Trull TW, Bidigare RR, Bishop JKB, Casciotti KL, Dehairs F, Elskens M, Honda M, Karl DM, Siegel DA, Silver MW, Steinberg DK, Valdes J, van Mooy B, Wilson S (2007) Revisiting carbon flux through the ocean’s twilight zone. Science 316:567–570. https://doi.org/10.1126/science.1137959
Cai P, Huang Y, Chen M, Liu G, Qiu Y (2002) New production in the South China Sea−a coupled 228Ra-nitrate approach. Science in China D 45:103–109. https://doi.org/10.1007/BF02879787
Cai P, Zhao D, Wang L, Huang B, Dai M (2015) Role of particle stock and phytoplankton community structure in regulating particulate organic carbon export in a large marginal sea. J Geophys Res Oceans 120:2063–2095. https://doi.org/10.1002/2014JC010432
Chai F, Dugdale RC, Peng TH, Wilkerson FP, Barber RT (2002) One-dimensional ecosystem model of the equatorial Pacific upwelling system. Part I: model development and silicon and nitrogen cycle. Deep-Sea Res Pt II 49:2713–2745. https://doi.org/10.1016/s0967-0645(02)00055-3
Chen Y, Wu Z, Li QP (2018) Temporal change of export production at Xisha of the northern South China Sea. J Geophys Res 123:9305–9319. https://doi.org/10.1029/2017JC013619
Chu PC, Wang G (2003) Seasonal variability of thermohaline front in the central South China Sea. J Oceanogr 59:65–78. https://doi.org/10.1023/A:1022868407012
Cram JA, Weber T, Leung SW, McDonnell AMP, Liang J-H, Deutsch C (2018) The role of particle size, ballast, temperature, and oxygen in the sinking flux to the deep sea. Glob Biogeochem Cycles 32:858–876. https://doi.org/10.1029/2017GB005710
De La Rocha CL (2007) The biological pump. In: Elderfield H (ed) Treatise on geochemistry, vol 6. Elsevier, Amsterdam, pp 83–111. https://doi.org/10.1016/B0-08-043751-6/06107-7
DeVries T, Weber T (2017) The export and fate of organic matter in the ocean: new constraints from combining satelliteand oceanographic tracer observations. Glob Biogeochem Cycles 31:535–555. https://doi.org/10.1002/2016GB005551
Du C, Liu Z, Kao S-J, Dai M (2017) Diapycnal fluxes of nutrients in an oligotrophic oceanic regime: the South China Sea. Geophys Res Lett 44:11510–11518. https://doi.org/10.1002/2017GL074921
Ducklow HW, Steinberg DK, Buesseler KO (2001) Upper ocean carbon export and the biological pump. Oceanography 14:50–58. https://doi.org/10.5670/oceanog.2001.06
Fairall CW, Bradley EF, Rogers DP, Edson JB, Young GS (1996) Bulk parameterization of air-sea fluxes for tropical ocean-global atmosphere Coupled-Ocean Atmosphere Response Experiment. J Geophys Res 101:3747–3764. https://doi.org/10.1029/95JC03205
Fang W, Fang G, Shi P, Huang Q, Xie Q (2002) Seasonal structures of upper layer circulation in the southern South China Sea from in situ observation. J Geophys Res 107:C113202. https://doi.org/10.1029/2002JC001343
Fennel K, Boss E (2003) Subserface maxima of phytoplankton and choorophyll: steady-state solutions from a simple model. Limnol Oceanogr 48:1521–1534
Geng B, Xiu P, Shu C, Zhang WZ, Chai F, Li S, Wang D (2019) Evaluating the roles of wind- and buoyancy flux-induced mixing on phytoplankton dynamics in the northern and central South China Sea. J Geophys Res 124:680–702. https://doi.org/10.1029/2018JC014170
Guidi L, Legendre L, Reygondeau G, Uitz J, Stemmann L, Henson SA (2015) A new look at ocean carbon remineralization forestimating deepwater sequestration. Glob Biogeochem Cycles 29:1044–1059. https://doi.org/10.1002/2014GB005063
Guo M, Xiu P, Li S, Chai F, Xue H, Zhou K, Dai M (2017) Seasonal variability and mechanisms regulating chlorophyll distribution in mesoscale eddies in the South China Sea. J Geophys Res Oceans 122:5329–5347. https://doi.org/10.1002/2016JC012670
Henson SA, Sanders R, Madsen E (2012) Global patterns in efficiency of particulate organic carbon export and transfer to the deep ocean. Glob Biogeochem Cycles 26:GB1028. https://doi.org/10.1029/2011gb004099
Ho TY, Chou, WC, Wei CL, Lin HL Wong GTF (2010) Trace metal cycling in the surface water of the South China Sea:Vertical fluxes and sources. Limnol Oceanogr 55, 1807–1820. https://doi.org/10.4319/lo.2010.55.5.1807
Hooker SB, McClain CR (2000) The calibration and validation of SeaWiFS data. Prog Oceanogr 45:427–465. https://doi.org/10.1016/S0079-6611(00)00012-4
Huang Y, Yang B, Chen B, Qiu G, Wang H, Huang B (2018) Net community production in the South China Sea basin estimated from in situ O2 measurements on an Argo profiling float. Deep-Sea Res Pt I 131:54–61. https://doi.org/10.1016/j.dsr.2017.11.002
Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woollen J, Zhu Y, Leetmaa A, Reynolds R, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteorol Soc 77:437–471. https://doi.org/10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2
Kara AB, Rochford PA, Hurlburt HE (2000) An optimal definition for ocean mixed layer depth. J Geophys Res Oceans 105:16803–16821. https://doi.org/10.1029/2000JC900072
Kriest I, Oschlies A (2008) On the treatment of particulate organic matter sinking in large-scale models of marine biogeochemical cycles. Biogeoscience 5:55–72. https://doi.org/10.5194/bg-5-55-2008
Legendre L, Rivkin RB, Weinbauer MG, Guidi L, Uitz J (2015) The microbial carbon pump concept: potential biogeochemical significance in the globally changing ocean. Prog Oceanogr 134:432–450. https://doi.org/10.1016/j.pocean.2015.01.008
Li QP, Wang Y, Dong Y, Gan J (2015) Modeling long-term change of planktonic ecosystems in the northern South China Sea and the upstream Kuroshio current. J Geophys Res Oceans 120:3913–3936. https://doi.org/10.1002/2014JC010609
Li H, Wiesner MG, Chen J, Ling Z, Zhang J, Ran L (2017) Long-term variation of mesopelagic biogenic flux in the central South China Sea: impact of monsoonal seasonality and mesoscale eddy. Deep-Sea Res 126(Pt I):62–72. https://doi.org/10.1016/j.dsr.2017.05.012
Lin I, Liu WT, Wu C-C, Wong GTF, Hu C, Chen Z, Liang W-D, Yang Y, Liu K-L (2003) New evidence for enhanced ocean primary production triggered by tropical cyclone. Geophys Res Lett 30:1718. https://doi.org/10.1029/2003GL017141
Liu G, Chai F (2009) Seasonal and interannual variability of primary and export production in the South China Sea: a three-dimensional physical–biogeochemical model study. ICES J Mar Sci 66:420–431. https://doi.org/10.1093/icesjms/fsn219
Liu KK, Chao SY, Shaw PT, Gong GC, Chen CC, Tang TY (2002) Monsoon-forced chlorophyll distribution and primary production in the South China Sea: observations and a numerical study. Deep-Sea Res Pt I 49:1387–1412. https://doi.org/10.1016/s0967-0637(02)00035-3
Liu KK, Wang LW, Dai M, Tseng CM, Yang Y, Sui CH, Oey L, Tseng KY, Huang SM (2013) Inter-annual variation of chlorophyll in the northern South China Sea observed at the SEATS Station and its asymmetric responses to climate oscillation. Biogeosciences 10:7449–7462. https://doi.org/10.5194/bg-10-7449-2013
Locarnini RA, Mishonov AV, Antonov JI et al (2013) World Ocean Atlas 2013, Volume 1: Temperature. In: Levitus S. Mishonov A (eds) NOAA Atlas NESDIS 73, pp 40. http://www.nodc.noaa.gov/OC5/indprod.html
Lu W, Yan XH, Han L, Jiang Y (2017) One-dimensional ocean model with three types of vertical velocities: a case study in the South China Sea. Ocean Dyn 67:253–262. https://doi.org/10.1007/s10236-016-1029-9
Lu W, Oey L-Y, Liao E, Zhuang W, Yan X-H, Jiang Y (2018) Physical modulation to the biological productivity in the summer Vietnam upwelling system. Ocean Sci 14:1303–1320. https://doi.org/10.5194/os-14-1303-2018
Lui H-K, Chen K-Y, Chen C-T, Wang BS, Lin HL, Ho SH, Tseng CJ, Yang Y, Chan JW (2018) Physical forcing-driven productivity and sediment flux to the deep basin of northern South China Sea: a decadal time series study. Sustainability 10:971. https://doi.org/10.3390/su10040971
Lutz M, Dunbar R, Caldeira K (2002) Regional variability in the vertical flux of particulate organic carbon in the ocean interior. Glob Biogeochem Cycles 16:1037–11-18. https://doi.org/10.1029/2000GB001383
Ma W, Chai F, Xiu P, Xue H, Tian J (2013) Modeling the long-term variability of phytoplankton functional groups and primary productivity in the South China Sea. J Oceanogr 69:527–544. https://doi.org/10.1007/s10872-013-0190-8
Ma W, Chai F, Xiu P, Xue H, Tian J (2014) Simulation of export production and biological pump structure in the South China Sea. Geo-Mar Lett 34:541–554. https://doi.org/10.1007/s00367-014-0384-0
Marsay CM, Sanders RJ, Henson SA, Pabortsava K, Achterberg EP, Lampitt RS (2015) Attenuation of sinking particulate organic carbon flux through the mesopelagic ocean. PNAS 112:1089–1094. https://doi.org/10.1073/pnas.1415311112
Martin JH, Knauer GA, Karl DM, Broenkow WW (1987) VERTEX: carbon cycling in the northeast Pacific. Deep-Sea Res Pt A 34:267–285. https://doi.org/10.1016/0198-0149(87)90086-0
McCreary JP, Yu ZJ, Hood RR, Vinaychandran PN, Furue R, Ishida A, Richards KJ (2013) Dynamics of the Indian-Ocean oxygen minimum zones. Prog Oceanogr 112:15–37. https://doi.org/10.1016/j.pocean.2013.03.002
McDonnell AMP, Buesseler KO (2010) Variability in the average sinking velocity of marine particles. Limnol Oceanogr 55:2085–2096. https://doi.org/10.4319/lo.2010.55.5.2085
Ning X, Chai F, Xue H, Cai Y, Liu C, Shi J (2004) Physical-biological oceanographic coupling influencing phytoplankton and primary production in the South China Sea. J Geophys Res 109:C10005. https://doi.org/10.1029/2004JC002365
Palacz AP, Xue HJ, Armbrecht C, Zhang CY, Chai F (2011) Seasonal and inter-annual changes in the surface chlorophyll of the South China Sea. J Geophys Res 116:C09015. https://doi.org/10.1029/2011JC007064
Pan G, Chai F, Tang D, Wang D (2017) Marine phytoplankton biomass responses to typhoon events in the South China Sea based on physical-biogeochemical model. Ecol Model 356:38–47. https://doi.org/10.1016/j.ecolmodel.2017.04.013
Patara L, Pinardi N, Corselli C, Malinverno E, Tonani M, Santoleri R, Masina S (2009) Particle fluxes in the deep Eastern Mediterranean basins: the role of ocean vertical velocities. Biogeosciences 6:333–348. https://doi.org/10.5194/bg-6-333-2009
Riley JS, Sanders R, Marsay C, Moigne FACL, Achterberg EP, Poulton AJ (2012) The relative contribution of fast and slow sinking particles to ocean carbon export. Glob Biogeochem Cycles 26:GB1026. https://doi.org/10.1029/2011GB004085
Sigman DM, Hain MP (2012) The biological productivity of the ocean. Nat Educ Knowl 3:21
Su J (2004) Overview of the South China Sea circulation and its influence on the coastal physical oceanography outside the Pearl River Estuary. Cont Shelf Res 24:1745–1760. https://doi.org/10.1016/j.csr.2004.06.005
Thomsen L, Aguzzi J, Costa C, De Leo F, Ogston A, Purser A (2017) The oceanic biological pump: rapid carbon transfer to depth at continental margins during winter. Sci Rep 7:10763. https://doi.org/10.1038/s41598-017-11075-6
Tréguer P, Bowler C, Moriceau B, Dutkiewicz S, Gehlen M, Aumont O, Bittner L, Dugdale R, Finkel Z, Iudicone D, Jahn O, Guidi L, Lasbleiz M, Leblanc K, Levy M, Pondaven P (2018) Influence of diatom diversity on the ocean biological carbon pump. Nat Geosci 11:27–37. https://doi.org/10.1038/s41561-017-0028-x
Villa-Alfageme M, de Soto F, Le Moigne FAC, Giering SLC, Sanders R, García-Tenorio R (2014) Observations and modeling of slow-sinking particles in the twilight zone. Glob Biogeochem Cycles 28:1327–1342. https://doi.org/10.1002/2014GB004981
Wang G, Su J, Chu PC (2003) Mesoscale eddies in the South China Sea observed with altimeter data. Geophys Res Lett 30:2121. https://doi.org/10.1029/2003GL018532
Wang G, Chen D, Su J (2006) Generation and life cycle of the dipole in the South China Sea summer circulation. J Geophys Res Oceans 111:C06002. https://doi.org/10.1029/2005JC003314
Weber T, Cram JA, Leung SW, DeVries T, Deutsch C (2016) Deep ocean nutrients imply large latitudinal variation in particle transferefficiency. Proc Natl Acad Sci U S A 113:8606–8611. https://doi.org/10.1073/pnas.1604414113
Wei CL, Lin SY, Sheu DD, Chou WC, Yi MC, Santschi PH, Wen LS (2011) Particle-reactive radionuclides (234Th, 210Pb, 210Po) as tracers for the estimation of export production in the South China Sea. Biogeosciences 8:3793–3808. https://doi.org/10.5194/bg-8-3793-2011
Wei C-L, Chia C-Y, Chou W-C, Lee W-H (2017) Sinking fluxes of 210Pb and 210Po in the deep basin of the northern South China Sea. J Environ Radioact 174:45–53. https://doi.org/10.1016/j.jenvrad.2016.05.026
Wyrtki K (1961) Physical oceanography of the southeast Asian waters (Naga Report). Scripps Inst. of Oceangr, La Jolla, CA, p 195
Xiao W, Wang L, Laws E, Xie Y, Chen J, Liu X, Chen B, Huang B (2018) Realized niches explain spatial gradients in seasonal abundance of phytoplankton groups in the South China Sea. Prog Oceanogr 162:223–239. https://doi.org/10.1016/j.pocean.2018.03.008
Xiu P, Chai F (2011) Modeled biogeochemical responses to mesoscale eddies in the South China Sea. J Geophys Res 116:C10006. https://doi.org/10.1029/2010JC006800
Xiu P, Chai F, Shi L, Xue H, Chao Y (2010) A census of eddy activities in the South China Sea during 1993-2007. J Geophys Res 115:C03012. https://doi.org/10.1029/2009JC005657
Zhang HM, Bates JJ, Reynolds RW (2006) Assessment of composite global sampling: sea surface wind speed. Geophys Res Lett 33:L17714. https://doi.org/10.1029/2006GL027086
Zhang YW, Liu ZF, Zhao YL, Wang WG, Li JR, Xu JP (2014) Mesoscale eddies transport deep-sea sediments. Sci Rep 4:5937. https://doi.org/10.1038/srep05937
Acknowledgments
Constructive comments from the editor and reviewers improved the quality of this paper. We thank Dr. Yunwei Yan and Dr. Bingxu Geng for valuable discussions. We are grateful to Dr. Zuojun Yu for her editing service. Satellite and reanalysis data were downloaded from the internet (the NCEP Reanalysis dataset, https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html, the OC-CCI V3.1, http://www.esa-oceancolour-cci.org/, the Blended Sea Wind dataset, ftp://eclipse.ncdc.noaa.gov/pub/seawinds/, WOA13 V2, https://www.nodc.noaa.gov/OC5/woa13/).
Funding
We also thank financial support from the National Key Research and Development Program of China (Grant No. 2016YFA0601101), National Natural Science Foundation of China (Grant No. 41876123, 41890805, 41576002, 41730536), the Scientific Research Fund of the Second Institute of Oceanography, Ministry of Natural Resources (Grant No. 14283).
Author information
Authors and Affiliations
Corresponding authors
Additional information
Responsible Editor: Ricardo de Camargo
This article is part of the Topical Collection on the 10th International Workshop on Modeling the Ocean (IWMO), Santos, Brazil, 25-28 June 2018
Electronic supplementary material
ESM 1
(DOCX 214 kb)
Rights and permissions
About this article
Cite this article
Ma, W., Xiu, P., Chai, F. et al. Seasonal variability of the carbon export in the central South China Sea. Ocean Dynamics 69, 955–966 (2019). https://doi.org/10.1007/s10236-019-01286-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10236-019-01286-y