Một khung lý thuyết để đại diện cho phân hủy vi sinh vật trong các mô hình khí hậu liên kết

Katherine E. O. Todd-Brown1, Francesca M. Hopkins1, Stephanie N. Kivlin2, Jennifer M. Talbot2, Steven D. Allison1,2
1Department of Earth System Science, University of California (Irvine), Irvine, USA
2Department of Ecology and Evolutionary Biology, University of California, Irvine, Irvine, USA

Tóm tắt

Dự đoán chính xác nồng độ CO2 trong khí quyển trong tương lai là điều cần thiết để đánh giá tác động của biến đổi khí hậu đối với hệ sinh thái và xã hội con người. Một nguồn gây ra sự không chắc chắn lớn trong các dự đoán mô hình là mức độ mà sự ấm lên toàn cầu sẽ làm tăng nồng độ CO2 trong khí quyển thông qua việc tăng cường phân hủy vi sinh vật của carbon hữu cơ trong đất. Những tiến bộ gần đây trong sinh thái vi sinh vật có thể giúp giảm bớt sự không chắc chắn này, nhưng các mô hình toàn cầu hiện tại không đại diện cho sự kiểm soát trực tiếp của vi sinh vật đối với quá trình phân hủy. Thay vào đó, tất cả các mô hình khí hậu liên kết được xem xét trong báo cáo gần đây nhất của Ủy ban Liên chính phủ về Biến đổi khí hậu (IPCC) đều giả định rằng phân hủy là một quá trình phân rã bậc một, tỷ lệ thuận với kích thước của kho carbon trong đất. Chúng tôi lập luận rằng cần phát triển một thế hệ mô hình mới liên kết phân hủy trực tiếp với kích thước và hoạt động của các quần thể vi sinh vật trong các mô hình toàn cầu liên kết. Quy trình này bắt đầu với việc xây dựng và xác minh các mô hình quy mô nhỏ tinh vi, nắm bắt các cơ chế vi sinh vật cơ bản mà không quá phức tạp về mặt toán học. Các mô hình cơ học này sau đó cần được mở rộng thông qua một quy trình tổng hợp và được xác minh từ quy mô hệ sinh thái đến quy mô toàn cầu trước khi được tích hợp vào các mô hình khí hậu toàn cầu (GCMs). Việc xác định tham số cho các mô hình vi sinh vật ở quy mô toàn cầu là một thách thức vì một số thuộc tính vi sinh vật như hoạt động enzyme ngoại bào tại chỗ rất khó để đo trực tiếp. Do đó, có thể cần phải có các quy trình điều chỉnh tham số mới để suy ra giá trị của các biến số vi sinh vật quan trọng. Việc xác minh các mô hình phân hủy ở quy mô toàn cầu cũng là một thách thức và vẫn chưa được hoàn thành với các mô hình carbon đất được nhúng trong các GCM hiện tại. May mắn thay, các tập dữ liệu toàn cầu mới về trữ lượng và dòng chảy carbon trong đất cung cấp cơ hội đầy hứa hẹn để xác minh cả các mô hình carbon đất hiện có và các mô hình vi sinh vật mới. Nếu có thể vượt qua những thách thức trong việc mở rộng, xác định tham số và xác minh, một thế hệ mới các mô hình phân hủy dựa trên vi sinh vật có thể cải thiện đáng kể các dự đoán về phản hồi carbon-khí hậu trong hệ thống Trái đất. Phát triển các cấu trúc mô hình mới cũng sẽ giảm thiểu bất kỳ thiên lệch nào do giả định về phân hủy bậc một trong tất cả các mô hình hiện tại được tham khảo trong các báo cáo của IPCC.

Từ khóa

#phân hủy vi sinh vật #mô hình khí hậu toàn cầu #carbon trong đất #biến đổi khí hậu #Ủy ban Liên chính phủ về Biến đổi khí hậu (IPCC)

Tài liệu tham khảo

Ågren GI, Bosatta E (1996a) Quality: a bridge between theory and experiment in soil organic matter studies. Oikos 76:522–528 Ågren GI, Bosatta E (1996b) Theoretical ecosystem ecology: understanding element cycles. Cambridge University Press, Cambridge Ågren G, Wetterstedt JÅM (2007) What determines the temperature response of soil organic matter decomposition? Soil Biol Biochem 39:1794–1798 Ågren G, Bosatta E, Magill AH (2001) Combining theory and experiment to understand effects of inorganic nitrogen on litter decomposition. Oecologia 128:94–98 Akaike H (1974) A new look at the statistical model evaluation. IEEE Trans Autom Control 19:716–723 Allison SD (2005) Cheaters, diffusion, and nutrients constrain decomposition by microbial enzymes in spatially structured environments. Ecol Lett 8:626–635 Allison SD (2006) Soil minerals and humic acids alter enzyme stability: implications for ecosystem processes. Biogeochemistry 81:361–373 Allison SD, Martiny JBH (2008) Resistance, resilience, and redundancy in microbial communities. Proc Natl Acad Sci USA 105(Suppl 1):11512–11519 Allison SD, Wallenstein MD, Bradford MA (2010) Soil-carbon response to warming dependent on microbial physiology. Nat Geosci 3:336–340 Andrews JA, Matamala R, Westover KM, Schlesinger WH (2000) Temperature effects on the diversity of soil heterotrophs and the 13C of soil-respired CO2. Soil Biol Biochem 32:699–706 Bardgett RD, Freeman C, Ostle NJ (2008) Microbial contributions to climate change through carbon cycle feedbacks. ISME J 2:805–814 Bond-Lamberty B, Thomson A (2010) Temperature-associated increases in the global soil respiration record. Nature 464:579–582 Bradford MA, Davies CA, Frey SD, Maddox TR, Melillo JM, Mohan JE, Reynolds JF, Treseder KK, Wallenstein MD (2008) Thermal adaptation of soil microbial respiration to elevated temperature. Ecol Lett 11:1316–1327. doi:10.1111/j.1461-0248.2008.01251.x Burns RG (1978) Soil enzymes. Academic Press, New York Burns RG (1982) Enzyme activity in soil: location and a possible role in microbial ecology. Soil Biol Biochem 14:423–427 Cadule P, Friedlingstein P, Bopp L, Sitch S, Jones CD, Ciais P, Piao SL, Peylin P (2010) Benchmarking coupled climate-carbon models against long-term atmospheric CO2 measurements. Glob Biogeochem Cycles 24:GB2016. doi:2010.1029/2009GB003556 Chapin FS III, McFarland J, McGuire AD, Euskirchen ES, Ruess RW, Kielland K (2009) The changing global carbon cycle: linking plant–soil carbon dynamics to global consequences. J Ecol 97:840–850 Cleveland CC, Liptzen D (2007) C:N:P stoichiometry in soil: is there a “Redfield ratio” for the microbial biomass? Biogeochemistry 85:235–252 Cornwell WK, Cornelissen JHC, Amatangelo K, Dorrepaal E, Eviner VT, Godoy O, Hobbie SE, Hoorens B, Kurokawa H, Harguindeguy NP, Quested HM, Santiago LS, Wardle DA, Wright IJ, Aerts R, Allison SD, van Bodegom P, Brovkin V, Chatain A, Callaghan T, Díaz S, Garnier E, Gurvich DE, Kazakou E, Klein JA, Read J, Reich PB, Soudzilovskai NA, Vaieretti MV, Westoby M (2008) Plant species traits are the predominant control on litter decomposition rates within biomes worldwide. Ecol Lett 11:1065–1071 Cox P (2001) Description of the “TRIFFID” dynamic global vegetation model. Technical note 24. Hadley Centre, Met Office Cox PM, Betts RA, Jones CD, Spall SA, Totterdell IJ (2000) Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model. Nature 408:184–187 Craine JM, Fierer N, McLauchlan KK (2010) Widespread coupling between the rate and temperature sensitivity of organic matter decay. Nat Geosci 3:854–857 Davidson EA, Janssens IA (2006) Temperature sensitivity of soil carbon decomposition and feedbacks to climate change. Nature 440:165–173 Davidson EA, Belk E, Boone RD (1998) Soil water content and temperature as independent or confounded factors controlling soil respiration in a temperate mixed hardwood forest. Glob Change Biol 4:217–227 Davidson EA, Janssens IA, Luo Y (2006) On the variability of respiration in terrestrial ecosystems: moving beyond Q10. Glob Change Biol 12:154–164 Devêvre OC, Horwath WR (2000) Decomposition of rice straw and microbial carbon use efficiency under different soil temperatures and moistures. Soil Biol Biochem 32:1773–1785 Dumbrell AJ, Ashton PD, Aziz N, Feng G, Nelson M, Dytham C, Fitter AH, Helgason T (2011) Distinct seasonal assemblages of arbuscular mycorrhizal fungi revealed by massively parallel pyrosequencing. New Phytol 190:794–804 Fierer N, Craine JM, McLauchlan K, Schimel JP (2005) Litter quality and the temperature sensitivity of decomposition. Ecology 86:320–326 Fischer G, Nachtergaele F, Prieler S, van Velthuizen HT, Verelst L, Wiberg D (2008) Global agro-ecological zones assessment for agriculture (GAEZ 2008). IIASA and FOA, Laxenburg and Rome Foley JA, Prentice IC, Ramankutty N, Levis S, Pollard D, Sitch S, Haxeltine A (1996) An integrated biosphere model of land surface processes, terrestrial carbon balance, and vegetation dynamics. Glob Biogeochem Cycles 10:603–628 Fontaine S, Barot S (2005) Size and functional diversity of microbe populations control plant persistence and long-term soil carbon accumulation. Ecol Lett 8:1075–1087 Friedlingstein P, Prentice IC (2010) Carbon-climate feedbacks: a review of model and observation based estimates. Curr Opin Environ Sustain 2:251–257 Friedlingstein P, Fung I, Holland E, John J, Brasseur G, Erickson D, Schimel D (1995) On the contribution of CO2 fertilization to the missing biospheric sink. Glob Biogeochem Cycles 9:541–556. doi:10.1029/95gb02381 Friedlingstein P, Cox P, Betts R, Bopp L, Von Bloh W, Brovkin V, Cadule P, Doney S, Eby M, Fung I, Bala G, John J, Jones C, Joos F, Kato T, Kawamiya M, Knorr W, Lindsay K, Matthews HD, Raddatz T, Rayner P, Reick C, Roeckner E, Schnitzler KG, Schnur R, Strassmann K, Weaver AJ, Yoshikawa C, Zeng N (2006) Climate-carbon cycle feedback analysis: results from the C4MIP model intercomparison. J Clim 19:3337–3353 German DP, Chacon SS, Allison SD (2011) Substrate concentration and enzyme allocation can affect rates of microbial decomposition. Ecology 92:1471–1480 Gershenson A, Bader NE, Cheng W (2009) Effects of substrate availability on the temperature sensitivity of soil organic matter decomposition. Glob Change Biol 15:176–183. doi:10.1111/j.1365-2486.2008.01827.x Hanson CA, Allison SD, Bradford MA, Wallenstein MD, Treseder KK (2008) Fungal taxa target different carbon sources in forest soil. Ecosystems 11:1157–1167 Hawkes CV, Kivlin SN, Rocca JD, Huguet V, Thomsen MA, Suttle KB (2011) Fungal community responses to precipitation. Glob Change Biol 17:1637–1645. doi:10.1111/j.1365-2486.2010.02327.x Hochachka PW, Somero GN (2002) Biochemical adaptation: mechanism and process in physiological evolution. Oxford University Press, Oxford IPCC (2007) Working group I contribution to the IPCC fourth assessment report. Climate change 2007: the physical science basis Ito A, Oikawa T (2002) A simulation model of the carbon cycle in land ecosystems (Sim-CYCLE): a description based on dry-matter production theory and plot-scale validation. Ecol Model 151:143–176 Jenkinson DS (1976) The effects of biocidal treatments on metabolism in soil—IV. The decomposition of fumigated organisms in soil. Soil Biol Biochem 8:203–208 Jenkinson DS, Rayner JH (1977) The turnover of soil organic matter in some of the Rothamsted classical experiments. Soil Sci 123:298–305 Jobbágy EG, Jackson RB (2000) The vertical distribution of soil organic carbon and its relation to climate and vegetation. Ecol Appl 10:423–436 Karhu K, Fritze H, Hämäläinen K, Vanhala P, Junger H, Oinonen M, Sonninen E, Tuomi M, Spetz P, Kitunen V, Liski J (2010) Temperature sensitivity of soil carbon fractions in boreal forest soil. Ecology 91:370–376 Kleber M, Nico PS, Plante A, Filley T, Kramer M, Swanston C, Sollins P (2011) Old and stable soil organic matter is not necessarily chemically recalcitrant: implications for modeling concepts and temperature sensitivity. Glob Change Biol 17:1097–1107 Knorr W (2000) Annual and interannual CO2 exchanges of the terrestrial biosphere: process-based simulations and uncertainties. Glob Ecol Biogeogr 9:225–252. doi:10.1046/j.1365-2699.2000.00159.x Knutti R, Allen MR, Friedlingstein P, Gregory JM, Hegerl GC, Meehl GA, Meinshausen M, Murphy JM, Plattner GK, Raper SCB, Stocker TF, Stott PA, Teng H, Wigley TML (2008) A review of uncertainties in global temperature projections over the twenty-first century. J Clim 21:2651–2663. doi:10.1175/2007JCLI2119.1 Kögel-Knabner I (2002) The macromolecular organic composition of plant and microbial residues as inputs to soil organic matter. Soil Biol Biochem 34:139–162 Krinner G, Viovy N, de Noblet-Ducoudré N, Ogée J, Polcher J, Friedlingstein P, Ciais P, Sitch S, Prentice IC (2005) A dynamic global vegetation model for studies of the coupled atmosphere-biosphere system. Glob Biogeochem Cycles 19:GB1015. doi:1010.1029/2003gb002199 Kuzyakov Y, Friedel JK, Stahr K (2000) Review of mechanisms and quantification of priming effects. Soil Biol Biochem 32:1485–1498 Lawrence CR, Neff JC, Schimel JP (2009) Does adding microbial mechanisms of decomposition improve soil organic matter models? A comparison of four models using data from a pulsed rewetting experiment. Soil Biol Biochem 41:1923–1934 Liang C, Cheng G, Wixon D, Balser T (2011) An Absorbing Markov Chain approach to understanding the microbial role in soil carbon stabilization. Biogeochemistry. doi:10.1007/s10533-010-9525-3 Lipson DA, Schmidt SK (2004) Seasonal changes in an alpine soil bacterial community in the Colorado Rocky Mountains. Appl Environ Microbiol 70:2867–2879 Lloyd J, Taylor JA (1994) On the temperature dependence of soil respiration. Funct Ecol 8:315–323 Luo Y (2007) Terrestrial carbon-cycle feedback to climate warming. Annu Rev Ecol Evol Syst 38:683–712 Malcolm GM, López-Gutiérrez JC, Koide RT, Eissenstat DM (2008) Acclimation to temperature and temperature sensitivity of metabolism by ectomycorrhizal fungi. Glob Change Biol 14:1169–1180 Manzoni S, Trofymow JA, Jackson RB, Porporato A (2010) Stoichiometric controls on carbon, nitrogen, and phosphorus dynamics in decomposing litter. Ecol Monogr 80:89–106. doi:10.1890/09-0179.1 Matthews HD, Eby M, Ewen T, Friedlingstein P, Hawkins BJ (2007) What determines the magnitude of carbon cycle-climate feedbacks? Glob Biogeochem Cycles 21:GB2012. doi:2010.1029/2006gb002733 McGuire KL, Treseder KK (2010) Microbial communities and their relevance for ecosystem models: decomposition as a case study. Soil Biol Biochem 42:529–535 Meir P, Cox P, Grace J (2006) The influence of terrestrial ecosystems on climate. Trends Ecol Evol 21:254–260 Metropolis N, Rosenbluth AW, Rosenbluth MN, Teller AH, Teller E (1953) Equations of state calculations by fast computing machines. J Chem Phys 21:1087–1092 Moorhead DL, Sinsabaugh RL (2006) A theoretical model of litter decay and microbial interaction. Ecol Monogr 76:151–174 Morales P, Sykes MT, Prentice IC, Smith P, Smith B, Bugmann H, Zierl B, Friedlingstein P, Viovy N, Sabaté S, Sánchez A, Pla E, Gracia CA, Sitch S, Arneth A, Ogee J (2005) Comparing and evaluating process-based ecosystem model predictions of carbon and water fluxes in major European forest biomes. Glob Change Biol 11:2211–2233 Ostle NJ, Smith P, Fisher R, Ian Woodward F, Fisher JB, Smith JU, Galbraith D, Levy P, Meir P, McNamara NP, Bardgett RD (2009) Integrating plant-soil interactions into global carbon cycle models. J Ecol 97:851–863 Pansu M, Sarmiento L, Rujano MA, Ablan M, Acevedo D, Bottner P (2010) Modeling organic transformations by microorganisms of soils in six contrasting ecosystems: validation of the MOMOS model. Glob Biogeochem Cycles 24:GB1008. doi:1010.1029/2009GB003527 Parton WJ, Stewart JWB, Cole CV (1988) Dynamics of C, N, P, and S in grassland soils—a model. Biogeochemistry 5:109–131 Parton WJ, Scurlock JMO, Ojima DS, Gilmanov TG, Scholes RJ, Schimel DS, Kirchner T, Menaut JC, Seastedt T, Moya EG, Kamnalrut A, Kinyamario JI (1993) Observations and modeling of biomass and soil organic matter dynamics for the grassland biome worldwide. Glob Biogeochem Cycles 7:785–809 Potter CS, Randerson JT, Field CB, Matson PA, Vitousek PM, Mooney HA, Klooster SA (1993) Terrestrial ecosystem production: a process model based on global satellite and surface data. Glob Biogeochem Cycles 7:811–841 Raich JW, Russell AE, Kitayama K, Parton WJ, Vitousek PM (2006) Temperature influences carbon accumulation in moist tropical forests. Ecology 87:76–87 Randerson JT, Thompson MV, Malmstrom CM, Field CB, Fung IY (1996) Substrate limitations for heterotrophs: implications for models that estimate the seasonal cycle of atmospheric CO2. Glob Biogeochem Cycles 10:585–602. doi:10.1029/96gb01981 Randerson JT, Hoffman FM, Thornton PE, Mahowald NM, Lindsay K, Lee Y-H, Nevison CD, Doney SC, Bonan G, Stökli R, Covey C, Running SW, Fung IY (2009) Systematic assessment of terrestrial biogeochemistry in coupled climate-carbon models. Glob Change Biol 15:2462–2484 Ricciuto DM, Davis KJ, Keller K (2008) A Bayesian calibration of a simple carbon cycle model: the role of observations in estimating and reducing uncertainty. Glob Biogeochem Cycles 22:GB2030. doi:2010.1029/2006gb002908 Saleska SR, Shaw MR, Fischer ML, Dunne JA, Still CJ, Holman ML, Harte J (2002) Plant community composition mediates both large transient decline and predicted long-term recovery of soil carbon under climate warming. Glob Biogeochem Cycles 16:1055. doi:1010.1029/2001GB001573 Schimel J (1995) Ecosystem consequences of microbial diversity and community structure. In: Chapin FS III, Körner C (eds) Arctic and alpine biodiversity. Ecological studies, vol 113. Springer-Verlag, Berlin, pp 239–254 Schimel J (2001) Biogeochemical models: implicit versus explicit microbiology. In: Schulze ED, Harrison SP, Heimann M et al (eds) Global biogeochemical cycles in the climate system. Academic Press, San Diego, pp 177–183 Schimel JP, Bennett J (2004) Nitrogen mineralization: challenges of a changing paradigm. Ecology 85:591–602 Schimel JP, Weintraub MN (2003) The implications of exoenzyme activity on microbial carbon and nitrogen limitation in soil: a theoretical model. Soil Biol Biochem 35:549–563 Schlesinger WH (1997) Biogeochemistry: an analysis of global change. Academic Press, San Diego Schlesinger WH (2004) Better living through biogeochemistry. Ecology 85:2402–2407 Schwalm CR, Williams CA, Schaefer K, Anderson R, Arain MA, Baker I, Barr A, Black TA, Chen GS, Chen JM, Ciais P, Davis KJ, Desai A, Dietze M, Dragoni D, Fischer ML, Flanagan LB, Grant R, Gu LH, Hollinger D, Izaurralde RC, Kucharik C, Lafleur P, Law BE, Li LH, Li ZP, Liu SG, Lokupitiya E, Luo YQ, Ma SY, Margolis H, Matamala R, McCaughey H, Monson RK, Oechel WC, Peng CH, Poulter B, Price DT, Riciutto DM, Riley W, Sahoo AK, Sprintsin M, Sun JF, Tian HQ, Tonitto C, Verbeeck H, Verma SB (2010) A model-data intercomparison of CO2 exchange across North America: results from the North American Carbon Program site synthesis. J Geophys Res Biogeosci 115:G00H05. doi:10.1029/2009jg001229 Sinsabaugh RL (1994) Enzymic analysis of microbial pattern and process. Biol Fertil Soils 17:69–74 Sinsabaugh RL, Antibus RK, Linkins AE (1991) An enzymic approach to the analysis of microbial activity during plant litter decomposition. Agric Ecosyst Environ 34:43–54 Sinsabaugh RL, Lauber CL, Weintraub MN, Ahmed B, Allison SD, Crenshaw C, Contosta AR, Cusack D, Frey S, Gallo ME, Gartner TB, Hobbie SE, Holland K, Keeler BL, Powers JS, Stursova M, Takacs-Vesbach C, Waldrop MP, Wallenstein MD, Zak DR, Zeglin LH (2008) Stoichiometry of soil enzyme activity at global scale. Ecol Lett 11:1252–1264 Sitch S, Smith B, Prentice IC, Arneth A, Bondeau A, Cramer W, Kaplan JO, Levis S, Lucht W, Sykes MT, Thonicke K, Venevsky S (2003) Evaluation of ecosystem dynamics, plant geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. Glob Change Biol 9:161–185. doi:10.1046/j.1365-2486.2003.00569.x Sitch S, Huntingford C, Gedney N, Levy PE, Lomas M, Piao SL, Betts R, Ciais P, Cox P, Friedlingstein P, Jones CD, Prentice IC, Woodward FI (2008) Evaluation of the terrestrial carbon cycle, future plant geography and climate-carbon cycle feedbacks using five Dynamic Global Vegetation Models (DGVMs). Glob Change Biol 14:2015–2039. doi:10.1111/j.1365-2486.2008.01626.x Sivia D, Skilling J (2006) Data analysis: a Bayesian tutorial. Oxford University Press, New York Skilling J (2006) Nested sampling for general Bayesian computation. Bayesian Anal 1:833–860 Smith P, Smith JU, Powlson DS, McGill WB, Arah JRM, Chertov OG, Coleman K, Franko U, Frolking S, Jenkinson DS, Jensen LS, Kelly RH, Klein-Gunnewiek H, Komarov AS, Li C, Molina JAE, Mueller T, Parton WJ, Thornley JHM, Whitmore AP (1997) A comparison of the performance of nine soil organic matter models using datasets from seven long-term experiments. Geoderma 81:153–225 Sokolov AP, Kicklighter DW, Melillo JM, Felzer BS, Schlosser CA, Cronin TW (2008) Consequences of considering carbon-nitrogen interactions on the feedbacks between climate and the terrestrial carbon cycle. J Clim 21:3776–3796. doi:10.1175/2008jcli2038.1 Steinweg JM, Plante AF, Conant RT, Paul EA, Tanaka DL (2008) Patterns of substrate utilization during long-term incubations at different temperatures. Soil Biol Biochem 40:2722–2728 Strickland MS, Lauber C, Fierer N, Bradford MA (2009) Testing the functional significance of microbial community composition. Ecology 90:441–451 Sutton R, Sposito G (2005) Molecular structure in soil humic substances: the new view. Environ Sci Technol 39:9009–9015 Suzuki T, Ichii K (2010) Evaluation of a terrestrial carbon cycle submodel in an Earth system model using networks of eddy covariance observations. Tellus B Chem Phys Meteorol 62:729–742. doi:10.1111/j.1600-0889.2010.00478.x Thornton PE, Rosenbloom NA (2005) Ecosystem model spin-up: estimating steady state conditions in a coupled terrestrial carbon and nitrogen cycle model. Ecol Model 189:25–48 Thornton PE, Lamarque JF, Rosenbloom NA, Mahowald NM (2007) Influence of carbon-nitrogen cycle coupling on land model response to CO2 fertilization and climate variability. Glob Biogeochem Cycles 21:GB4018. doi:4010.1029/2006GB002868 Trasar-Cepeda C, Gil-Sotres F, Leirós MC (2007) Thermodynamic parameters of enzymes in grassland soils from Galicia, NW Spain. Soil Biol Biochem 39:311–319 Treseder KK, Balser TC, Bradford MA, Brodie EL, Dubinsky EA, Eviner VT, Hofmockel KS, Lennon JT, Levine UY, MacGregor BJ, Pett-Ridge J, Waldrop MP (2011a) Integrating microbial ecology into ecosystem models: challenges and priorities. Biogeochemistry. doi:10.1007/s10533-011-9636-5 Treseder KK, Kivlin SN, Hawkes CV (2011b) Evolutionary trade-offs among decomposers determine responses to nitrogen enrichment. Ecol Lett. doi:10.1111/j.1461-0248.2011.01650.x Tringe SG, von Mering C, Kobayashi A, Salamov AA, Chen K, Chang HW, Podar M, Short JM, Mathur EJ, Detter JC, Bork P, Hugenholtz P, Rubin EM (2005) Comparative metagenomics of microbial communities. Science 308:554–557 Trumbore S (2000) Age of soil organic matter and soil respiration: radiocarbon constraints on belowground C dynamics. Ecol Appl 10:399–411 van Ginkel JH, Gorissen A, Polci D (2000) Elevated atmospheric carbon dioxide concentration: effects of increased carbon input in a Lolium perenne soil on microorganisms and decomposition. Soil Biol Biochem 32:449–456 Vetter YA, Denning JW, Jumars PA, Krieger-Brockett BB (1998) A predictive model of bacterial foraging by means of freely released extracellular enzymes. Microb Ecol 36:75–92 von Lützow M, Kögel-Knabner I, Ekschmitt K, Matzner E, Guggenberger G, Marschner B, Flessa H (2006) Stabilization of organic matter in temperate soils: mechanisms and their relevance under different soil conditions—a review. Eur J Soil Sci 57:426–445 Vrugt JA, ter Braak CJF, Diks CGH, Higdon D, Robinson BA, Hyman JM (2009) Accelerating Markov chain Monte Carlo simulation by differential evolution with self-adaptive randomized subspace sampling. Int J Nonlinear Sci Numer Simul 10:273–290 Waldrop MP, Balser TC, Firestone MK (2000) Linking microbial community composition to function in a tropical soil. Soil Biol Biochem 32:1837–1846 Wallenstein MD, Hall EK (2011) A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning. Biogeochemistry. doi:10.1007/s10533-011-9641-8 Wallenstein MD, Weintraub MN (2008) Emerging tools for measuring and modeling in situ activity of soil extracellular enzymes. Soil Biol Biochem 40:2098–2106 Wang YP, Trudinger CM, Enting IG (2009) A review of applications of model-data fusion to studies of terrestrial carbon fluxes at different scales. Agric For Meteorol 149:1829–1842. doi:10.1016/j.agrformet.2009.07.009 Wetterstedt JÅM, Ågren GI (2011) Quality or decomposer efficiency—which is most important in the temperature response of litter decomposition? A modelling study using the GLUE methodology. Biogeosciences 8:477–487. doi:10.5194/bg-8-477-2011 Williams M, Rastetter EB, Fernandes DN, Goulden ML, Shaver GR, Johnson LC (1997) Predicting gross primary productivity in terrestrial ecosystems. Ecol Appl 7:882–894 Wutzler T, Reichstein M (2008) Colimitation of decomposition by substrate and decomposers—a comparison of model formulations. Biogeosciences 5:749–759 Zeng N, Mariotti A, Wetzel P (2005) Terrestrial mechanisms of interannual CO2 variability. Glob Biogeochem Cycles 19:GB1016. doi:1010.1029/2004GB002273