Nitrogen uptake regime regulated by ice melting during austral summer in the Prydz Bay, Antarctica
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摘要: 本研究将稳定同位素(15N)与放射性核素(226Ra)示踪相结合,探讨了2006年夏季南极普里兹湾融冰过程对氮吸收的调控作用。硝酸盐及铵盐的比吸收速率均与浓度呈正相关关系,表明底物浓度效应的存在。开阔洋区具有较高的f比值,而在埃默里冰架附近f比值低得多。f比值与冰融水份额之间存在负相关关系,暗示融冰过程在调控水体氮吸收方面起着重要作用。融冰改变了当地上层水体的层化条件,显著地影响南大洋的生物泵效率及对大气二氧化碳的吸收。本研究为南大洋上层水体碳、氮动力学的调控机制提供了新的认识,且有助于对历史记录的解读及对未来气候变化的预测。Abstract: Using a combination of stable isotope (15N) and radionuclide (226Ra) analyses, we examine possible controls on the interactions between melting ice and the uptake of nitrogen in the Prydz Bay during the 2006 austral summer. We find that specific rates of uptake for nitrate and ammonium correlate positively to their concentrations, thus suggesting a substrate effect. In the study area, we observe that regions along open, oceanic water have high f-ratios (nitrate uptake/nitrate+ammonium uptake), while areas near the Amery Ice Shelf have significantly low f-ratios. Further analysis reveals a negative correlation between the f-ratio and the melt water fraction, thus implying that the melting of ice plays an essential role in regulating pelagic N dynamics in the Southern Ocean (SO). Stratification, produced by melting ice, should profoundly affect the efficiency of the SO’s biological pump and consequently affect the concentration of CO2 in the atmosphere. Results presented in this study add information to an already significant base of understanding of the controls on pelagic C and N dynamics in the SO. This provides unique insights for either interpreting past changes in geologic records or for predicting future climate change trends.
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Key words:
- nitrogen uptake regime /
- ice melting /
- Prydz Bay /
- Antarctica
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Arrigo K R, Robinson D H, Worthen D L, et al. 1999. Phytoplankton community structure and the drawdown of nutrients and CO2 in the Southern Ocean. Science, 283(5400): 365-367, doi: 10.1126/science.283.5400.365 Arrigo K R, Van Dijken G L. 2003. Phytoplankton dynamics within 37 Antarctic coastal polynya systems. Journal of Geophysical Research, 108(C8): 3271, doi: 10.1029/2002JC001739 Assmy P, Smetacek V, Montresor M, et al. 2013. Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current. Proceedings of the National Academy of Sciences of the United States of America, 110(51): 20633-20638, doi: 10.1073/pnas.1309345110 Bury S J, Owen N J P, Preston T. 1995. 13C and 15N uptake by phytoplankton in the marginal ice zone of the Bellingshausen Sea. Deep Sea Research Part Ⅱ: Topical Studies in Oceanography, 42(4-5): 1225-1252, doi: 10.1016/0967-0645(95)00065-X Cai Yuming, Ning Xiuren, Zhu Genghai, et al. 2005. Size fractionated biomass and productivity of phytoplankton and new production in the Prydz Bay and the adjacent Indian sector of the Southern Ocean during the austral summer 1998/1999. Acta Oceanologica Sinica, 27(4): 135-147 Chen Liqi, Chen Min, Zhan Liyang, et al. 2017. Review of CHINARE chemical oceanographic research in the Southern Ocean during 1984-2016. Advances in Polar Science, 28(2): 139-150 Cochlan W P. 2008. Nitrogen uptake in the Southern Ocean. In: Capone D G, Bronk D A, Mulholland M R, et al., eds. Nitrogen in the Marine Environment. 2nd ed. San Diego: Academic Press, 569-596 De La Rocha C L, Passow U. 2007. Factors influencing the sinking of POC and the efficiency of the biological carbon pump. Deep Sea Research Part Ⅱ: Topical Studies in Oceanography, 54(5-7): 639-658, doi: 10.1016/j.dsr2.2007.01.004 DiFiore P J, Sigman D M, Karsh K L, et al. 2010. Poleward decrease in the isotope effect of nitrate assimilation across the Southern Ocean. Geophysical Research Letters, 37(17): L17601 DiTullio G R, Grebmeier J M, Arrigo K R, et al. 2000. Rapid and early export of Phaeocystis antarctica blooms in the Ross Sea, Antarctica. Nature, 404(6778): 595-598, doi: 10.1038/35007061 Ducklow H W, Steinberg D K, Buesseler K O. 2001. Upper ocean carbon export and the biological pump. Oceanography, 14(4): 50-58, doi: 10.5670/oceanog Dugdale R C, Wilkerson F P. 1986. The use of 15N to measure nitrogen uptake in eutrophic oceans; Experimental considerations. Limnology and Oceanography, 31(4): 673-689, doi: 10.4319/lo.1986.31.4.0673 Eppley R W, Peterson B J. 1979. Particulate organic matter flux and planktonic new production in the deep ocean. Nature, 282(5740): 677-680, doi: 10.1038/282677a0 Gao Zhongyong, Chen Liqi, Gao Yuan. 2008. Air-sea carbon fluxes and their controlling factors in the Prydz Bay in the Antarctic. Acta Oceanologica Sinica, 27(3): 136-146 Han Zhengbing, Hu Chuanyu, Xue Bin, et al. 2011. Particulate organic carbon in the surface water of South Ocean and Prydz Bay during the austral summer of 2007/2008 and 2008/2009. Chinese Journal of Polar Research (in Chinese), 23(1): 11-18 Hansen H P, Koroleff F. 1999. Determination of nutrients. In: Grasshoff K, Kremling K, Ehrhardt M, eds. Methods of Seawater Analysis. 3rd ed. Weinheim: Wiley-VCH, 170-198 He Jianhua, Ma Hao, Chen Liqi, et al. 2007. The estimates of the particulate organic carbon export fluxes in Prydz Bay, Southern Ocean using 234Th/238U disequilibria. Haiyang Xuebao (in Chinese), 29(4): 69-76 Hurd C L, Berges J A, Osborne J, et al. 1995. An in vitro nitrate reductase assay for marine macroalgae: optimization and characterization of the enzyme for Fucus gardneri (Phaeophyta). Journal of Phycology, 31(5): 835-843, doi: 10.1111/j.0022-3646.1995.00835.x Kemeny P C, Weigand M A, Zhang R, et al. 2016. Enzyme-level interconversion of nitrate and nitrite in the fall mixed layer of the Antarctic Ocean. Global Biogeochemical Cycles, 30(7): 1069-1085, doi: 10.1002/2015GB005350 Liu Chenggang, Ning Xiuren, Sun Jun, et al. 2004. Size structure of standing stock and productivity and new production of phytoplankton in the Prydz Bay and the adjacent Indian sector of the Southern Ocean during the austral summer of 2001/2002. Haiyang Xuebao (in Chinese), 26(6): 107-117 Long M C, Thomas L N, Dunbar R B. 2012. Control of phytoplankton bloom inception in the Ross Sea, Antarctica, by Ekman restratification. Global Biogeochemical Cycles, 26(1): GB1006 Massom R A, Stammerjohn S E. 2010. Antarctic sea ice change and variability-Physical and ecological implications. Polar Science, 4(2): 149-186, doi: 10.1016/j.polar.2010.05.001 Mengesha S, Dehairs F, Fiala M, et al. 1998. Seasonal variation of phytoplankton community structure and nitrogen uptake regime in the Indian Sector of the Southern Ocean. Polar Biology, 20(4): 259-272, doi: 10.1007/s003000050302 Pu Shuzhen, Dong Zhaoqian. 2003. Progress in physical oceanographic studies of Prydz Bay and its adjacent oceanic area. Chinese Journal of Polar Research (in Chinese), 15(1): 53-64 Ren Chunyan, Chen Min, Gao Zhongyong, et al. 2015. Stable carbon isotopic composition of suspended particulate organic matter in the Prydz Bay and its adjacent areas. Haiyang Xuebao (in Chinese), 37(12): 74-84 Sarmiento J L, Gruber N, Brzezinski M A, et al. 2004. High-latitude controls of thermocline nutrients and low latitude biological productivity. Nature, 427(6969): 56-60, doi: 10.1038/nature02127 Smetacek V, Klaas C, Strass V H, et al. 2012. Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature, 487(7407): 313-319, doi: 10.1038/nature11229 Smith W O Jr, Marra J, Hiscock M R, et al. 2000. The seasonal cycle of phytoplankton biomass and primary productivity in the Ross Sea, Antarctica. Deep Sea Research Part Ⅱ: Topical Studies in Oceanography, 47(15-16): 3119-3140, doi: 10.1016/S0967-0645(00)00061-8 Smith W O Jr, Nelson D M. 1986. Importance of ice edge phytoplankton production in the Southern Ocean. BioScience, 36(4): 251-257, doi: 10.2307/1310215 Sweeney C, Hansell D A, Carlson C A, et al. 2000. Biogeochemical regimes, net community production and carbon export in the Ross Sea, Antarctica. Deep Sea Research Part Ⅱ: Topical Studies in Oceanography, 47(15-16): 3369-3394, doi: 10.1016/S0967-0645(00)00072-2 Vaz R A N, Lennon G W. 1996. Physical oceanography of the Prydz Bay region of Antarctic waters. Deep Sea Research Part I: Oceanographic Research Papers, 43(5): 603-641, doi: 10.1016/0967-0637(96)00028-3 Wu Li, Wang Rujian, Xiao Wenshen, et al. 2017. Productivity-climate coupling recorded in Pleistocene sediments off Prydz Bay (East Antarctica). Palaeogeography, Palaeoclimatology, Palaeoecology, 485: 260-270, doi: 10.1016/j.palaeo.2017.06.018 Zhang Run, Zheng Minfang, Chen Min, et al. 2014. An isotopic perspective on the correlation of surface ocean carbon dynamics and sea ice melting in Prydz Bay (Antarctica) during austral summer. Deep Sea Research Part I: Oceanographic Research Papers, 83: 24-33, doi: 10.1016/j.dsr.2013.08.006 Zhao Jun, Han Zhengbing, Pan Jianming. 2014. Spatial and temporal variation of phytoplankton indicated by multi-proxies in Prydz Bay, Antarctica. Research of Environmental Sciences (in Chinese), 27(6): 589-594 Zhu Genhai, Pan Jianming, Yu Peisong, et al. 2007. Phytoplankton in Prydz Bay and its adjacent sea area of Antarctica during the austral summer (2005/2006). Proceedings of the China Symposium on Polar Science (in Chinese), Xining. Shanghai: Polar Research Institute of China, 72
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