N2 fixation rate and diazotroph community structure in the western tropical North Pacific Ocean
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摘要: 生物固氮作用是海洋最主要的外源性新氮来源。本研究报道了热带北太平洋西部(13-20°N,120-160°E,WTNP)基于15N稳定同位素示踪法测定固氮速率及基于分子生物学手段所获得固氮生物组成信息。固氮速率的粒级分布及固氮生物组成信息共同证实,在采样时期WTNP得固氮作用主要来自单细胞固氮生物的贡献。在一条东西向断面上的结果表明,固氮生物组成从中心海盆区的单细胞蓝藻(UCYN-B)为主,向西边界流(黑潮区)转变为以束毛藻为主。推测固氮生物组成的空间变化,在很大程度上反映了微量营养盐可获得性的调控。表层水固氮速率变化范围是0.6-2.6 nmol/(L d),平均值为1.2±0.5 nmol/(L d),在135°E-160°E之间,固氮速率的主要贡献份额(88%±6%)来自 <10 μm粒级。深度积分(0-200 m)固氮速率变化范围是150-480 μmol/(m2 d),平均值为225±105 μmol/(m2 d)。进一步地,估算固氮作用可支持初级生产力氮需求的份额是6.2%±3.7%,表明固氮作用是WTNP重要的新氮来源。考虑到WTNP对气候变化相当敏感,有必要对该海区加强研究,以厘清固氮作用在海洋生物地球化学循环中的作用。Abstract: In the present study, we report N2 fixation rate (15N isotope tracer assay) and the diazotroph community structure (using the molecular method) in the western tropical North Pacific Ocean (WTNP) (13°–20°N, 120°–160°E). Our independent evidence on the basis of both in situ N2 fixation activity and diazotroph community structure showed the dominance of unicellular N2 fixation over majority of the WTNP surface waters during the sampling periods. Moreover, a shift in the diazotrophic composition from unicellular cyanobacteria group B-dominated to Trichodesmium spp.-dominated toward the western boundary current (Kuroshio) was also observed in 2013. We hypothesize that nutrient availability may have played a major role in regulating the biogeography of N2 fixation. In surface waters, volumetric N2 fixation rate (calculated by nitrogen) ranged between 0.6 and 2.6 nmol/(L·d) and averaged (1.2±0.5) nmol/(L·d), with < 10 μm size fraction contributed predominantly (88%±6%) to the total rate between 135°E and 160°E. Depth-integrated N2 fixation rate over the upper 200 m ranged between 150 μmol/(m2·d) and 480 μmol/(m2·d) (average (225±105) μmol/(m2·d). N2 fixation can account for 6.2%±3.7% of the depth-integrated primary production, suggesting that N2 fixation is a significant N source sustaining new and export production in the WTNP. The role of N2 fixation in biogeochemical cycling in this climate change-vulnerable region calls for further investigations.
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Bonnet S, Biegala I C, Dutrieux P, et al. 2009. Nitrogen fixation in the western equatorial Pacific:Rates, diazotrophic cyanobacterial size class distribution, and biogeochemical significance. Global Biogeochemical Cycles, 23(3):GB3012 Böttjer D, Dore J E, Karl D M, et al. 2017. Temporal variability of nitrogen fixation and particulate nitrogen export at Station ALOHA. Limnology and Oceanography, 62(1):200-216, doi: 10.1002/lno.10386 Brown M T, Landing W M, Measures C I. 2005. Dissolved and particulate Fe in the western and central North Pacific:Results from the 2002 IOC cruise. Geochemistry, Geophysics, Geosystems, 6(10):Q10001, doi: 10.1029/2004GC000893 Cabrera O, Villanoy C, Alabia I D, et al. 2015. Shifts in chlorophyll a off Eastern Luzon, Philippines, associated with the North Equatorial Current bifurcation latitude. Oceanography (Washington D.C.), 28(4):46-53, doi: 10.5670/oceanog.2015.80 Capone D G, Zehr J P, Paerl H W, et al. 1997. Trichodesmium, a globally significant marine cyanobacterium. Science, 276(5316):1221-1229, doi: 10.1126/science.276.5316.1221 Caporaso J G, Kuczynski J, Stombaugh J, et al. 2010. QIIME allows analysis of high-throughput community sequencing data. Nature Methods, 7(5):335-336, doi: 10.1038/nmeth.f.303 Carpenter K E. 1998. An introduction to the oceanography, geology, biogeography, and fisheries of the tropical and subtropical western and central Pacific. In:Carpenter K E, Niem V H, eds. FAO Species Identification Guide for Fishery Purposes. Rome:The Living Marine Resources of the Western Central Pacific Carpenter E J, Harvey H R, Fry B, et al. 1997. Biogeochemical tracers of the marine cyanobacterium Trichodesmium. Deep Sea Research Part I:Oceanographic Research Papers, 44(1):27-38, doi: 10.1016/S0967-0637(96)00091-X Carpenter E J, Montoya J P, Burns J, et al. 1999. Extensive bloom of a N2-fixing diatom/cyanobacterial association in the tropical Atlantic Ocean. Marine Ecology Progress Series, 185:273-283, doi: 10.3354/meps185273 Chen Y L L, Chen H Y, Lin Y H, et al. 2014. The relative contributions of unicellular and filamentous diazotrophs to N2 fixation in the South China Sea and the upstream Kuroshio. Deep Sea Research Part I:Oceanographic Research Papers, 85:56-71, doi: 10.1016/j.dsr.2013.11.006 Church M J, Björkman K M, Karl D M, et al. 2008. Regional distributions of nitrogen-fixing bacteria in the Pacific Ocean. Limnology and Oceanography, 53(1):63-77, doi: 10.4319/lo.2008.53.1.0063 Church M J, Mahaffey C, Letelier R M, et al. 2009. Physical forcing of nitrogen fixation and diazotroph community structure in the North Pacific subtropical gyre. Global Biogeochemical Cycles, 23(2):GB2020 Clement A, DiNezio P. 2014. The tropical Pacific Ocean-back in the driver's seat? Science, 343(6174):976-978, doi: 10.1126/science.1248115 Cravatte S, Delcroix T, Zhang Dongxiao, et al. 2009. Observed freshening and warming of the western Pacific Warm Pool. Climate Dynamics, 33(4):565-589, doi: 10.1007/s00382-009-0526-7 Deutsch C, Sarmiento J L, Sigman D M, et al. 2007. Spatial coupling of nitrogen inputs and losses in the ocean. Nature, 445(7124):163-167, doi: 10.1038/nature05392 Dyhrman S T, Chappell P D, Haley S T, et al. 2006. Phosphonate utilization by the globally important marine diazotroph Trichodesmium. Nature, 439(7072):68-71, doi: 10.1038/nature04203 Dyhrman S T, Haley S T. 2006. Phosphorus scavenging in the unicellular marine diazotroph Crocosphaera watsonii. Applied and Environmental Microbiology, 72(2):1452-1458, doi: 10.1128/AEM.72.2.1452-1458.2006 Fish J A, Chai Benli, Wang Qiong, et al. 2013. FunGene:the functional gene pipeline and repository. Fronters in Microbiology, 4:291, doi: 10.3389/fmicb.2013.00291 Fu F X, Yu E, Garcia N S, et al. 2014. Differing responses of marine N2 fixers to warming and consequences for future diazotroph community structure. Aquatic Microbial Ecology, 72(1):33-46, doi: 10.3354/ame01683 Gruber N, Sarmiento J L. 1997. Global patterns of marine nitrogen fixation and denitrification. Global Biogeochemical Cycles, 11(2):235-266, doi: 10.1029/97GB00077 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 Hashihama F, Furuya K, Kitajima S, et al. 2009. Macro-scale exhaustion of surface phosphate by dinitrogen fixation in the western North Pacific. Geophysical Research Letters, 36(3):L03610 Jacq V, Ridame C, L'Helguen S, et al. 2014. Response of the unicellular diazotrophic cyanobacterium Crocosphaera watsonii to iron limitation. PLoS One, 9(1):e86749, doi: 10.1371/journal.pone.0086749 Jiang Z B, Li H L, Zhai H C, et al. 2018. Seasonal and spatial changes in Trichodesmium associated with physicochemical properties in East China Sea and southern Yellow Sea. Journal of Geophysical Research:Biogeosciences, 123(2):509-530, doi: 10.1002/2017JG004275 Jickells T, Moore C M. 2015. The importance of atmospheric deposition for ocean productivity. Annual Review of Ecology, Evolution, and Systematics, 46:481-501, doi: 10.1146/annurev-ecolsys-112414-054118 Karl D M, Michaels A F, Bergman B, et al. 2002. Dinitrogen fixation in the world's oceans. Biogeochemistry, 57(1):47-98, doi: 10.1023/A:1015798105851 Kim D, Jeong J H, Kim T W, et al. 2017. The reduction in the biomass of cyanobacterial N2 fixer and the biological pump in the Northwestern Pacific Ocean. Scientific Reports, 7:41810, doi: 10.1038/srep41810 Kitajima S, Furuya K, Hashihama F, et al. 2009. Latitudinal distribution of diazotrophs and their nitrogen fixation in the tropical and subtropical western North Pacific. Limnology and Oceanography, 54(2):537-547, doi: 10.4319/lo.2009.54.2.0537 Klawonn I, Lavik G, Böning P, et al. 2015. Simple approach for the preparation of 15-15N2-enriched water for nitrogen fixation assessments:evaluation, application and recommendations. Frontiers in Microbiology, 6:769 Kodama T, Furuya K, Hashihama F, et al. 2011. Occurrence of rain-origin nitrate patches at the nutrient-depleted surface in the East China Sea and the Philippine Sea during summer. Journal of Geophysical Research:Oceans, 116(C8):C08003 Lehodey P, Bertignac M, Hampton J, et al. 1997. El Nino Southern Oscillation and tuna in the Western Pacific. Nature, 389(6652):715-718, doi: 10.1038/39575 Martino M, Hamilton D, Baker A R, et al. 2014. Western Pacific atmospheric nutrient deposition fluxes, their impact on surface ocean productivity. Global Biogeochemical Cycles, 28(7):712-728, doi: 10.1002/2013GB004794 Mohr W, Großkopf T, Wallace D W R, et al. 2010. Methodological underestimation of oceanic nitrogen fixation rates. PLoS One, 5(9):e12583, doi: 10.1371/journal.pone.0012583 Montoya J P, Voss M, Kähler P, et al. 1996. A simple, high-precision, high-sensitivity tracer assay for N2 fixation. Applied and Environmental Microbiology, 62(3):986-993 Montoya J P, Holl C M, Zehr J P, et al. 2004. High rates of N2 fixation by unicellular diazotrophs in the oligotrophic Pacific Ocean. Nature, 430(7003):1027-1031, doi: 10.1038/nature02824 Qiu Bo, Rudnick D L, Cerovecki I, et al. 2015. The pacific north equatorial current:new insights from the origins of the Kuroshio and Mindanao Currents (OKMC) Project. Oceanography, 28(4):24-33, doi: 10.5670/oceanog.2015.78 Ren Haojia, Chen Yichi, Wang X T, et al. 2017. 21st-century rise in anthropogenic nitrogen deposition on a remote coral reef. Science, 356(6339):749-752, doi: 10.1126/science.aal3869 Saito M A, Bertrand E M, Dutkiewicz S, et al. 2011. Iron conservation by reduction of metalloenzyme inventories in the marine diazotroph Crocosphaera watsonii. Proceedings of the National Academy of Sciences of the United States of America, 108(6):2184-2189, doi: 10.1073/pnas.1006943108 Shiozaki T, Kodama T, Furuya K. 2014. Large-scale impact of the island mass effect through nitrogen fixation in the western South Pacific Ocean. Geophysical Research Letters, 41(8):2907-2913, doi: 10.1002/2014GL059835 Shiozaki T, Kodama T, Kitajima S, et al. 2013. Advective transport of diazotrophs and importance of their nitrogen fixation on new and primary production in the western Pacific warm pool. Limnology and Oceanography, 58(1):49-60, doi: 10.4319/lo.2013.58.1.0049 Shiozaki T, Bombar D, Riemann L, et al. 2017. Basin scale variability of active diazotrophs and nitrogen fixation in the North Pacific, from the tropics to the subarctic Bering Sea. Global Biogeochemical Cycles, 31(6):996-1009, doi: 10.1002/2017GB005681 Wang Q, Garrity G M, Tiedje J M, et al. 2007. Naive Bayesian classifier for rapid assignment of rRNA sequences into the new bacterial taxonomy. Applied and Environmental Microbiology, 73(16):5261-5267, doi: 10.1128/AEM.00062-07 Wannicke N, Benavides M, Dalsgaard T, et al. 2018. New perspectives on nitrogen fixation measurements using 15N2 gas. Frontiers in Marine Science, 5:120, doi: 10.3389/fmars.2018.00120 Wolfe D A, Schelske C L. 1967. Liquid scintillation and Geiger counting efficiencies for Carbon-14 incorporated by marine phytoplankton in productivity measurements. ICES Journal of Marine Science, 31(1):31-37, doi: 10.1093/icesjms/31.1.31 Yang Guang, Li Chaolun, Guilini K, et al. 2017. Regional patterns of δ13C and δ15N stable isotopes of size-fractionated zooplankton in the western tropical North Pacific Ocean. Deep Sea Research Part I:Oceanographic Research Papers, 120:39-47, doi: 10.1016/j.dsr.2016.12.007 Zehr J P, Turner P J. 2001. Nitrogen fixation:Nitrogenase genes and gene expression. Methods in Microbiology, 30:271-286, doi: 10.1016/S0580-9517(01)30049-1 Zehr J P, Waterbury J B, Turner P J, et al. 2001. Unicellular cyanobacteria fix N2 in the subtropical North Pacific Ocean. Nature, 412(6847):635-638, doi: 10.1038/35088063 Zhang Run, Chen Min, Cao Jianping, et al. 2012. Nitrogen fixation in the East China Sea and southern Yellow Sea during summer 2006. Marine Ecology Progress Series, 447:77-86, doi: 10.3354/meps09509 Zhang Run, Chen Min, Ma Qiang, et al. 2011. Latitudinal distribution of nitrogen isotopic composition in suspended particulate organic matter in tropical/subtropical seas. Isotopes in Environmental and Health Studies, 47(4):489-497, doi: 10.1080/10256016.2011.622442 Zhang Dongsheng, Lu Douding, Li Hongliang, et al. 2014. Seasonal dynamics of Trichodesmium in the northern East China Sea. Continental Shelf Research, 88:161-170, doi: 10.1016/j.csr.2014.05.016
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