Application of Stable Isotopes in Studies of Gas Exchange Processes Between Biosphere and the Atmosphere

생태계와 대기 간의 가스 교환 메카니즘 규명을 위한 안정동위원소의 응용

  • Han, Gwang-Hyun (Department of Agricultural Chemistry, Chungbuk National University) ;
  • Chung, Doug-Young (Department of Bioenvironmental Chemistry, Chungnam National University)
  • Received : 2010.03.30
  • Accepted : 2010.04.14
  • Published : 2010.04.30

Abstract

In comparison with other terrestrial ecosystems, rice paddies are unique because they provide the primary food source for over 50% of the world's population, and act as major sources of global methane. The present paper summerizes a long-term field study that combine carbon isotopes, and canopy-scale flux measurements in an irrigated rice paddy, in conjugation with continuous monitoring of environmental, and vegetational factors. Both $CO_2$, and methane fluxes were largely influenced by soil temperature, and moisture conditions, especially across drainage events. Soil-entrapped $CO_2$, and methane showed a gradually increasing trend throughout growing season, but rapidly decreased upon flood water drainage. These variations in flux were well correlated with changes in concentration, and isotope ratio of soil $CO_2$, and methane, and of atmospheric $CO_2$, and methane within, and above the canopy. The isotopic signature of the gas exchange process varied markedly in response to change in contribution of soil respiration, belowground storage, fraction of $CO_2$ recycled, magnitude, and direction of $CO_2$ exchange, transport mechanism, and fraction of methane oxidized. Our results clearly demonstrate that stable isotope analysis can be a useful tool to study underlying mechanisms of gas exchange processes under natural conditions.

이 논문은 장기간에 걸쳐 논 생태계에서 측정된 이산화탄소와 메탄의 순교환량 과 이와 동시에 모니터링된 다양한 환경요소들과의 상관관계들을 살펴보고, 이들 플럭스와 환경 요소 및 생태계 요소들이 어떻게 교환된 이산화탄소와 메탄의 동위원소비에 영향을 미치는 지를 파악하고자 하였다. 생육기간 동안 관측된 이산화탄소 및 메탄의 순교환량은 는 담수기에는 각각 일사량과 토양온도의 변화에 따라 경시적인 변화를 보였으나, 낙수기를 전후해서는 토양에 저장되어 있던 가스들이 낙수 후 확산장벽이 사라짐으로 인해 급격히 대기 중으로 대량 방출되는 경향을 보였다. 이러한 플럭스의 변화는 토양 중에 저장되어 있는 이산화탄소와 메탄의 저장량 감소와 직접적으로 연결되었고, 이에 상응하는 순교환량 중 토양의 기여분 증가와 대기 중 이산화탄소 및 메탄의 농도 증가 및 동위원소비 변화가 관찰되었다. 이러한 변화는 환원상태에서 진행되는 메탄생성의 결과로, 기질인 이산화탄소는 상대적으로 무거운 $^{13}C$ 동위원소가 축적되는 반면, 생성물인 메탄은 가벼운 $^{12}C$ 동위원소가 축적되기 때문으로 판단된다. 따라서, 토양 유래 이산화탄소는 식물체 호흡 유래 이산화탄소와 구분되는 동위원소 특성을 지내게 된다. Keeling plot 혼합 모델로 추정된 이산화탄소와 메탄의 가스교환 동위원소 지문은 담수기와 낙수기에 걸쳐 매우 뚜렷한 변화를 보였으며, 그 변화 정도는 토양 중 가스 저장량, 교환된 플럭스의 크기 및 방향, 이동 경로, 부분적인 방출 이산화탄소의 재흡수도, 메탄의 산화정도 등에 의해 크게 달랐다. 본 연구의 결과들은 자연상태에서 관측된 플럭스와 결합된동위원소 기술이 생태계 내 다양한 가스 교환 메커니즘을 이해하는데 매우 유용한 도구가 될 수 있음을 보여주였다.

Keywords

References

  1. Baldocchi, D., E. Falge, L.H. Gu, R. Olson, D. Hollinger, S. Running, P. Anthoni, C. Bernhofer, K. Davis, R. Evans, J. Fuentes, A. Goldstein, G. Katul, B. Law, X.H. Lee, Y. Malhi, T. Meyers, W. Munger, W. Oechel, K.T.P. U, K. Pilegaerd, H.P. Schmid, R. Valentini, S. Verma, T. Vesala, K. Wilson, and S. Wofsy, 2001. FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities, Bulletin of the American Meteorological Society. 82:2415-2434. https://doi.org/10.1175/1520-0477(2001)082<2415:FANTTS>2.3.CO;2
  2. Bilek, R.S., S.C. Tyler, R.L. Sass, and F.M. Fisher. 1999. Differences in $CH_{4}$ oxidation and pathways of production between rice cultivars deduced from measurements of $CH_{4}$ flux and 13C of $CH_{4}$ and $CO_{2}$, Global Biogeochem. Cycles. 13:1029-1044. https://doi.org/10.1029/1999GB900040
  3. Boehme, S.E., N.E. Blair, J.P. Chanton, and C.S. Martens. 1996. A mass balance of 13C and 12C in an organic-rich methane-producing marine sediment, Geochim. Cosmochim. Acta. 60:3835-3848. https://doi.org/10.1016/0016-7037(96)00204-9
  4. Bowling, D.R., McDowell, N.G., Bond, B.J., Law, B.E., and Ehleringer, J.R. 2002. $^{13}C$ content of ecosystem respiration is linked to precipitation and vapor pressure deficit, Oecologia. 131: 113-124. https://doi.org/10.1007/s00442-001-0851-y
  5. Bowling, D.R., D.E. Pataki, and J.R. Ehleringer. 2003. Critical evaluation of micrometeorological methods for measuring ecosystem-atmosphere isotopic exchange of $CO_{2}$, Agricultural and Forest Meteorology. 116:159-179. https://doi.org/10.1016/S0168-1923(03)00006-6
  6. Bowling, D.R., P.P. Tans, and R.K. Monson, 2001. Partitioning net ecosystem carbon exchange with isotopic fluxes of $CO_{2}$, Global Change Biology. 7:127-145. https://doi.org/10.1046/j.1365-2486.2001.00400.x
  7. Campbell, C.S., J.L. Heilman, K.J. McInnes, L.T. Wilson, J.C. Medley, G. Wu, and D.R. Cobos. 2001. Diet and seasonal variation in $CO_{2}$ flux of irrigated rice. Agric. For. Meteorol. 108:15-27. https://doi.org/10.1016/S0168-1923(01)00225-8
  8. Chanton, J.P., G.J. Whiting, N.E. Blair, C.W. Lindau, and P.K. Bollich. 1997. Methane emission from rice: Stable isotopes, diurnal variations, and $CO_{2}$ exchange. Global Biogeochemical Cycles. 11:15-27. https://doi.org/10.1029/96GB03761
  9. Cicerone, R.J., and J.D. Shetter. 1981. Sources of atmospheric methane: Measurements in rice paddies and a discussion. Journal of Geophysical Research- Oceans and Atmospheres. 86:7203-7209. https://doi.org/10.1029/JC086iC08p07203
  10. Conrad, R., M. Klose, and P. Claus. 2002. Pathway of $CH_{4}$ formation in anoxic rice field soil and rice roots determined by $^{13}C$-stable isotope fractionation. Chemosphere. 47:797-806. https://doi.org/10.1016/S0045-6535(02)00120-0
  11. Ehleringer, J.R., and C.S. Cook. 1998. Carbon and oxygen isotope ratios of ecosystem respiration along an Oregon conifer transect: preliminary observations based on small-flask sampling. Tree Physiology. 18:513-519. https://doi.org/10.1093/treephys/18.8-9.513
  12. Fey, A., P. Claus, and R. Conrad. 2004. Temporal change of 13C-isotope signatures and methanogenic pathways in rice field soil incubated anoxically at different temperatures, Geochim. Cosmochim. Acta. 68:293-306. https://doi.org/10.1016/S0016-7037(03)00426-5
  13. Greaver, T., L.D.L. Stemberg, B. Schaffer, and T. Moreno. 2005. An empirical method of measuring $CO_{2}$. recycling by isotopic enrichment of respired $CO_{2}$, Agricultural and Forest Meteorology. 128:67-79. https://doi.org/10.1016/j.agrformet.2004.08.007
  14. Griffis, T.J., T.A. Black, D. Gaumont-Guay, G.B. Drewitt, Z. Nesic, A.G. Barr, K. Morgenstern, and N. Kljun. 2004. Seasonal variation and partitioning of ecosystem respiration in a southern boreal aspen forest. Agricultural and Forest Meteorology. 125:207-223. https://doi.org/10.1016/j.agrformet.2004.04.006
  15. Han, G.H., H. Yoshikoshi. H. Nagai, T. Yamada, M. Saito, A. Miyata, and A. Harazono. 2003. Concentration and carbon isotope profiles of $CH_{4}$ in paddy rice canopy. Geochimica et Cosmochimica Acta. 67:A131-A131.
  16. Han, G.H., H. Yoshikoshi, H. Nagai, T. Yamada, M. Saito, A. Miyeta. and Y. Harazono, 2005a, Concentration and carbon isotope profiles of $CH_{4}$ in paddy rice canopy: Isotopic evidence for changes in $CH_{4}$ emission pathways upon drainage, Chemical Geology. 218:25-40. https://doi.org/10.1016/j.chemgeo.2005.01.024
  17. Han, G.H., H. Yoshikcshi, H. Nagai, T. Yamada, M. Saito, A. Miyata, and Y. Harazono. 2005b. Late growing season $CH_{4}$ budget in a rice paddy determined using stable carbon isotope, emission flux and soil storage measurements. Organic Geochemistry. 36:789-801. https://doi.org/10.1016/j.orggeochem.2005.01.004
  18. Han, G.H., H.Yoshikoshi, H. Nagai, T. Yamada, K. Ono, M. Mano, and A. Miyata. 2007. Isotopic disequilibrium between carbon assimilated and respired in a rice paddy as influenced by methanogenesis from $CO_{2}$, J. Geophys. Res. 112:G02016, doi:10.1029/2006JG000219.
  19. Heinsch, F.A., J.L. Heilman, K.J. McInnes, D.R. Cobos, D.A. Zuberer, and D.L Roelke. 2004. Carbon dioxide exchange in a high marsh on the Texas Gulf Coast: effects of freshwater availability. Agric. For. Meteorol. 125:159-172. https://doi.org/10.1016/j.agrformet.2004.02.007
  20. Holzapfel-Pschorn, A., and W. Seiler. 1986. Methane emission during a cultivation period from an Italian rice paddy. Journal of Geophysical Research- Atmospheres. 91:1803-1814.
  21. Intergovernmental Panel on Climate Change (IPCC). 2001. Climate Change 2001: The Scientific Basis, Houghton et al. (eds.), Cambridge Univ. Press, New York, pp. 385-391.
  22. Keeling, C.D. 1958. The concentration and isotopic abundances of atmospheric carbon dioxide in rural areas. Geochimica et Cosmochimica Acta. 13:322-334. https://doi.org/10.1016/0016-7037(58)90033-4
  23. Kruger, M., G. Eller, R. Conrad, and P. Frenzel. 2002. Seasonal variation in pathways of $CH_{4}$ production and in $CH_{4}$ oxidation in rice fields determined by stable carbon isotopes and specific inhibitors. Global Change Biology. 8:265-280. https://doi.org/10.1046/j.1365-2486.2002.00476.x
  24. Lai, C.T., A.J. Schauer, C. Owensby, J.M. Harn, and J.R. Ehleringer. 2003. Isotopic air sampling in a tallgrass prairie to partition net ecosystem $CO_{2}$ exchange. Journal of Geophysical Research- Atmospheres. 108, 4566, doi: 10.1029/2002JD003369.
  25. Miller, J.B., P.P. Tans, J.W.C. White, T.J. Conway, and B.W. Vaughn. 2003. The atmospheric signal of terrestrial carbon isotopic discrimination and its implication for partitioning carbon fluxes. Tellus Series B- Chemical and Physical Meteorology. 55:197-206. https://doi.org/10.1034/j.1600-0889.2003.00019.x
  26. Miyata, A., R. Leuning, O.T. Denmead, J. Kim, and Y. Harazono. 2000. Carbon dioxide and methane fluxes from an intermittently flooded paddy field. Agricultural and Forest Meteorology. 102:287-303. https://doi.org/10.1016/S0168-1923(00)00092-7
  27. Pataki, D.E., J.R. Ehleringer, L.B. Flanagan, D. Yakir, D.R. Bowling, C.J. Still, N. Buchmann, J.O. Kaplan, and J.A. Berry. 2003. The application and interpretation of Keeling plots in terrestrial carbon cycle research. Global Biogeochemical Cycles. 17:1022, doi:10.1029/2001GB001850.
  28. Saito, M., A. Miyata, H. Nagai, and T. Yamada. 2005. Seasonal variation or carbon dioxide exchange In rice paddy field in Japan. Agricultural and Forest Meteorology. 135:93-109. https://doi.org/10.1016/j.agrformet.2005.10.007
  29. Sass, R.L., F.M. Fisher, F.T. Tumerm and M.F. Jund. 1991. Methane emission from rice fields as influenced by solar radiation, temperature, and straw incorporation. Global Biogeochemical Cycles. 5:335-350. https://doi.org/10.1029/91GB02586
  30. Schutz., H., W. Seiler, and R. Conrad. 1989. Processes involved in formation and emission of methane in rice paddies. Biogeochemistry. 7:33-53.
  31. Sternberg, L.D.S., M.Z. Moreira, L.A. Martinelli, R.L. Victoria, E.M. Barbosa, L.C.M. Bonates, and D.C. Nepstad. 1997. Carbon dioxide recyeling in two Amazonian tropical forests. Agricultural and Forest Meteorology. 88:259-268. https://doi.org/10.1016/S0168-1923(97)00038-5
  32. Styles, J.M., M.R. Raupach, G.D. Farquhar, O. Kolle, K.A. Lawton, W.A. Brand, R.A. Werner, A. Jordan, E.D. Schulze, O. Shibistova, and J. Lloyd. 2002. Soil and canopy $CO_{2}$, $^{13}CO_{2}$, $H_{2}O$ and sensible heat flux partitions in a forest canopy inferred from concentration measurements. Tellus Series B- Chemical and Physical Meteorology. 54:655-676. https://doi.org/10.1034/j.1600-0889.2002.01356.x
  33. Tyler, S.C., R.S. Bilek, R.L. Sass, and F.M. Fisher. 1997. Methane oxidation and pathways of production in a Texas paddy field deduced from measurements of flux, $^{13}C$, and D of $CH_4$. Global Biogeochemical Cycles. 11:323-348. https://doi.org/10.1029/97GB01624
  34. Wang, X.F., and D. Yakir. 2000. Using stable isotopes of water in evapotranspiration studies. Hydrological Processes. 14:1407-1421. https://doi.org/10.1002/1099-1085(20000615)14:8<1407::AID-HYP992>3.0.CO;2-K
  35. Wassmann, R., H.U. Neue, R.S. Lantin, J.B. Aduna, M.C.R. Alberto, M.J. Andales, M.J. Tan, H.A.C. Denter van der Gen, H. Hoffmann. H. Papen, H. Rennenberg, and W. Seiler. 1994. Temporal patterns of methane emissions from wetland rice fields treated by different modes of N application. J. Geophys. Res. 99:16457-16462. https://doi.org/10.1029/94JD00017
  36. Yagi, K., H. Tsuruta, K. Kanda, and K. Minami. 1996. Effect of water management on methane emission from a Japanese rice paddy field: Automated methane monitoring, Global Biogeochem. Cycles. 10:255-267. https://doi.org/10.1029/96GB00517
  37. Yakir, D., and L.D.L. Sternberg. 2000. The use of stable isotopes to study ecosystem gas exchange. Oecclogia. 123:297-311. https://doi.org/10.1007/s004420051016
  38. Yakir, D., and X.F. Wang. 1996. Fluxes of $CO_{2}$ and water between terrestrial vegetation and the atmosphere estimated from isotope measurements. Nature. 380:515. https://doi.org/10.1038/380515a0
  39. Yepez, E.A., D.G. Williams, R.L. Scott, and G.H. Lin. 2003. Partitioning overstory and understory evapotranspiration in a semiarid savanna woodland from the isotopic composition of water vapor. Agricultural and Forest Meteorology. 119:53-68. https://doi.org/10.1016/S0168-1923(03)00116-3
  40. Zobitz, J.M., J.P. Keener, H. Schnyder, and D.R. Bowling. 2006. Sensitivity analysis and quantification of uncertainty for isotopic mixing relationships in carbon cycle research. Agricultural and Forest Meteorology. 136:56-75. https://doi.org/10.1016/j.agrformet.2006.01.003