남극해 드레이크해협 해수의 질산염 농도와 질소동위원소 값의 변화
Variation of Nitrate Concentrations and δ 15N Values of Seawater in the Drake Passage, Antarctic Ocean
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Seawater samples were collected at discrete depths from five stations across the polar front in the Drake Passage (Antarctic Ocean) by the 20th Korea Antarctic Research Program in December, 2006. Nitrate concentrations of seawater increase with depth within the photic zone above the depth of Upper Circumpolar Deep Water (UCDW). In contrast, δ 15N values of seawater nitrate decrease with depth, showing a mirror image to the nitrate variation. Such a distinct vertical variation is mainly attributed to the degree of nitrate assimilation by phytoplankton as well as organic matter degradation of sinking particles within the surface layer. The preferential 14NO3- assimilation by the phytoplankton causes 15NO3− concentration to become high in a closedsystem surface-water environment during the primary production, whereas more 14NO3− is added to the seawater during the degradation of sinking organic particles. The water-mass mixing seems to play an important role in the alteration of δ 15N values in the deep layer below the UCDW. Across the polar front, nitrate concentrations of surface seawater decrease and corresponding δ 15N values increase northward, which is likely due to the degree of nitrate utilization during the primary production. Based on the Rayleigh model, the calculated ε (isotope effect of nitrate uptake) values between 4.0‰ and 5.8‰ were validated by the previously reported data, although the preformed δ 15NO3− initial value of UCDW is important in the calculation of ε values.
Abstract
Seawater samples were collected at discrete depths from five stations across the polar front in the Drake Passage (Antarctic Ocean) by the 20th Korea Antarctic Research Program in December, 2006. Nitrate concentrations of seawater increase with depth within the photic zone above the depth of Upper Circumpolar Deep Water (UCDW). In contrast, δ 15N values of seawater nitrate decrease with depth, showing a mirror image to the nitrate variation. Such a distinct vertical variation is mainly attributed to the degree of nitrate assimilation by phytoplankton as well as organic matter degradation of sinking particles within the surface layer. The preferential 14NO3- assimilation by the phytoplankton causes 15NO3− concentration to become high in a closedsystem surface-water environment during the primary production, whereas more 14NO3− is added to the seawater during the degradation of sinking organic particles. The water-mass mixing seems to play an important role in the alteration of δ 15N values in the deep layer below the UCDW. Across the polar front, nitrate concentrations of surface seawater decrease and corresponding δ 15N values increase northward, which is likely due to the degree of nitrate utilization during the primary production. Based on the Rayleigh model, the calculated ε (isotope effect of nitrate uptake) values between 4.0‰ and 5.8‰ were validated by the previously reported data, although the preformed δ 15NO3− initial value of UCDW is important in the calculation of ε values.
참고문헌 (45)
- Altabet, M.A., "Isotopic tracers of the marine nitrogen cycle: Present and past, In: The Handbook of Environmental Chemistry", pp.251~293 (2006), Springer
- Altabet, M.A., "Sedimentary nitrogen isotopic ratio as a recorder for surface ocean nutrient utilization", Glob. Biogeochem. Cycles, 8, pp.103~116 (1994)
- Bakker, D.E., "Changes of carbon dioxide in surface waters during spring in the Southern Ocean", Deep-Sea Res. II, 44, pp.91~127 (1997)
- Banse, K., "Low seasonality of low concentrations of surface chlorophyll in the Subantarctic water ring: Underwater irradiance, iron, or grazing", Prog. Oceanogr, 37, pp.241~291 (1996)
- Bohlke, J.K., "Interlaboratory comparison of reference materials for nitrogen isotope ratio measurements", Reference and intercomparison materials for stable isotopes of light elements, Vienna. International Atomic Energy Agency (1995)
- Braman, R.S., "Nanogram nitrite and nitrate determination in environmental and biologicalmaterials by vanadium (iii) reduction with chemiluminescence detection", Anal. Chem, 61, pp.2715~2718 (1989)
- Brandes J.A., "Isotopic composition of nitrate in the central Arabian Sea and eastern tropical North Pacific: A tracer for mixing and nitrogen cycles", Limnol. Oceanogr, 43, pp.1680~1689 (1998)
- Carmack, E., "Water characteristics of the Southern Ocean south of the Polar Front, In: A Voyage of Discovery" (1977), Pergamon Press
- Casciotti, K.L., "Measurement of the oxygen isotopic composition of nitrate on seawater and freshwater using the denitrifier method", Anal. Chem, 74, pp.4905~4912 (2002)
- Christensen, S., "Sub-parts-per billion nitrate method - Use of an N2O− producing denitrifier to convert NO3 − or (NO3 −)-15N to N2O.", Appl. Environ. Microbiol, 54, pp.1409~1413 (1988)
- Frank, V.M., "Iron and silicic acid availability regulate Si uptake in the Pacific sector of the Southern Ocean", Deep-Sea Res. II, 47, pp.3315~3338 (2000)
- Gonfiantini, R., "Standards and Intercomparison Materials Distributed by the IAEA for Stable Isotope Measurements", Reference and intercomparison materials for stable isotopes of light elements, Vienna. International Atomic Energy Agency, pp.13~29 (1995)
- Gordon, A.L., "Structure of Antarctic waters between 20oW and 170oW, In: Antarctic map folio series, v. 6.", pp.1~10 (1967), American Geography Society
- Gordon, A.L., "Winter mixed layer environment of Weddell Deep Water", J. Geophys. Res, 89, pp.637~640 (1967)
- Greenberg, E.P., "Nitrous-oxide as end product of denitrification by strains of fluorescent pseudomonads", Can. J. Microbiol, 23, pp.903~907 (1977)
- Holm-Hansen, O., "Primary production and the factors controlling phytoplankton growth in the Southern Ocean, In: Adaptations within Antarctic ecosystems on Antarctic Biology", Smithsonian Instit
- Hutchins, D.A., "Control of phytoplankton growth by iron and silicic acid availability in the subantarctic Southern Ocean: Experimental results from the SAZ project", J. Geophys. Res, 106, pp.31~ (2001)
- Karsh, K.L., "Relationship of nitrogen isotope fractionation to phytoplankton size and iron availability during the Southern Ocean Iron RElease Experiment (SOIREE).", Limnol. Oceanogr, 48, pp.1058~1068 (2003)
- Mariotti, A., "Experimental determination of nitrogen kinetic isotope fractionation: Some principles: Illustrations for the denitrification and nitrification processes", Plant Soil, 62, pp.413~430 (1981)
- Martin, J.H., "Iron in Antarctic waters", Nature, 345, pp.156~158 (1990)
- Minas, H.J., "Net community production in “high nutrient-low chlorophyll” waters of the tropical and Antarctic Oceans: Grazing vs. iron hypothesis", Oceanol. Acta, 15, pp.145~162 (1992)
- Montoya, J.P., "Isotopic fractionation during nitrate uptake by phytoplankton grown in continuous culture", J. Plankton Res, 17, pp.439~464 (1995)
- Needoba, J.A., "Nitrogen isotope fractionation in 12 species of marine phytoplankton during growth on nitrate", Mar. Ecol. Prog. Ser, 255, pp.81~91 (2003)
- Nelson, D.M., "A seasonal progression of Si limitation in the Pacific sector of the Southern Ocean", Deep-Sea Res. II, 48, pp.3973~3995 (2001)
- Orsi, A.H., "On the meridional extent and fronts of the Antarctic Circumpolar Current", Deep-Sea Res. I, 42, pp.641~673 (1995)
- Pennock, J.R., "Isotopic fractionation of ammonium and nitrate during uptake by Skeletonema costatum: Implications for δ 15N dynamics under bloom conditions", Limnol. Oceanogr, 41(3), pp.451~459 (1996)
- Raven, J.A., "The iron and molybdenum use efficiencies of plant growth with different energy, carbon and nitrogen sources", New Phytologist, 109, pp.279~285 (1988)
- Richards, F.A., "Anoxic basins and fjords, In: Chemical Oceanography" (1965), Academic Press
- Robertson, J.E., "summer-time sink for atmospheric carbon dioxide in the Southern Ocean between 88oW and 80oE", Deep-Sea Res. II, 42, pp.1081~1091 (1995)
- Sedwick, P.N., "Iron and manganese in the Ross Sea: seasonal iron limitation in Antarctic shelf waters", J. Geophys. Res, 105(11), pp.321~336 (2000)
- Sievers H.A., "Upper ocean characteristics in Drake Passage and adjoining areas of the Southern Ocean, 39oW-95oW, In: Antarctic and Resources Variability" (1988), Springer
- Sigman, D.M., "Glacial", interglacial variations in atmospheric carbon dioxide, 2000, pp.407, 859~869
- Sigman, D.M., "A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater", Anal. Chem, 73, pp.4145~4153 (2001)
- Sigman, D.M., "The δ 15N of nitrate in the Southern Ocean: Nitrogen cycling and circulation in the ocean interior", J. Geophys. Res, 105(19), pp.599~614 (2000)
- Sigman, D.M., "The δ 15N of nitrate in the Southern Ocean: Consumption of nitrate in surface waters", Glob. Biogeochem. Cycles, 13, pp.1149~1166 (1999)
- Smith, W.O., "Importance of ice edge phytoplankton production in the Southern Ocean", Bio- Science, 36, pp.251~257 (1986)
- Speer K., "Southern Ocean transformation in a coupled model with and without eddy mass fluxes", Tellus, 52, pp.554~565 (2000)
- Takeda, S., "Influence of iron availability on nutrient consumption ratio of diatoms in oceanic waters", Nature, 393, pp.774~777 (1988)
- Talley, L.D., "Antarctic Intermediate Water in the South Atlantic, In: The South Atlantic: The Present and Past Circulation" (1996), Springer
- Tomczak, M., "Regional Oceanography: An introduction", pp.422~ (1994), Elsevier Science
- Wada, E., "Nitrogen isotope fractionation and its significance in biogeochemical processes occurring in marine environments, In: Isotope Marine Chemistry", pp.375~398 (1980), Uchida Rokakuho
- Wada, E., "Nitrogen isotope effects in the assimilation of inorganic nitrogenous compounds", Geomicrobiol. J, 1, pp.85~101 (1978)
- Waser, N.A.D., "Nitrogen isotope fractionation during the uptake and assimilation of nitrate, nitrite, and urea by a marine diatom", Limnol. Oceanogr, 43, pp.215~224 (1998)
- Whitehead, J.A., "Thermohaline Ocean Processes and Models", Annu. Rev. Fluid Mech, 27, pp.89~113 (1995)
- Whitworth, T., "Water masses and currents of the Southern Ocean at the Greenwich meridian", J. Geophys. Res, 92, pp.6462~6467 (1987)