title: The use and misuse of V(c,max) in Earth System Models.
abstract: Earth System Models (ESMs) aim to project global change. Central to this aim is the need to accurately model global carbon fluxes. Photosynthetic carbon dioxide assimilation by the terrestrial biosphere is the largest of these fluxes, and in many ESMs is represented by the Farquhar, von Caemmerer and Berry (FvCB) model of photosynthesis. The maximum rate of carboxylation by the enzyme Rubisco, commonly termed V c,max, is a key parameter in the FvCB model. This study investigated the derivation of the values of V c,max used to represent different plant functional types (PFTs) in ESMs. Four methods for estimating V c,max were identified; (1) an empirical or (2) mechanistic relationship was used to relate V c,max to leaf N content, (3) V c,max was estimated using an approach based on the optimization of photosynthesis and respiration or (4) calibration of a user-defined V c,max to obtain a target model output. Despite representing the same PFTs, the land model components of ESMs were parameterized with a wide range of values for V c,max (-46 to +77% of the PFT mean). In many cases, parameterization was based on limited data sets and poorly defined coefficients that were used to adjust model parameters and set PFT-specific values for V c,max. Examination of the models that linked leaf N mechanistically to V c,max identified potential changes to fixed parameters that collectively would decrease V c,max by 31% in C3 plants and 11% in C4 plants. Plant trait data bases are now available that offer an excellent opportunity for models to update PFT-specific parameters used to estimate V c,max. However, data for parameterizing some PFTs, particularly those in the Tropics and the Arctic are either highly variable or largely absent.
authors.affiliation: Department of Environmental Sciences, Brookhaven National Laboratory, Upton, NY, 11973, USA, arogers@bnl.gov.
authors.forename: Alistair
authors.initials: A
authors.lastname: Rogers
mesh_terms: D001110:Arctic Regions; D002138:Calibration; D002245:Carbon Dioxide / Q000378:metabolism*; D019069:Cell Respiration; D018534:Earth, Planet; D017753:Ecosystem; D008962:Models, Theoretical; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase; D009584:Nitrogen
references.citation: Proc Natl Acad Sci U S A. 1997 Dec 9;94(25):13730-4
references.pmid: 9391094
references.citation: J Exp Bot. 2008;59(7):1767-77
references.pmid: 18227079
references.citation: Proc Natl Acad Sci U S A. 2006 May 9;103(19):7246-51
references.pmid: 16641091
references.citation: J Exp Bot. 2003 Nov;54(392):2393-401
references.pmid: 14512377
references.citation: Plant Physiol. 1992 Dec;100(4):1737-43
references.pmid: 16653191
references.citation: J Exp Bot. 2002 Apr;53(369):609-20
references.pmid: 11886880
references.citation: J Exp Bot. 2001 Jul;52(360):1555-61
references.pmid: 11457916
references.citation: J Exp Bot. 2008;59(7):1581-95
references.pmid: 18436544
references.citation: Plant Physiol. 1998 Nov;118(3):945-55
references.pmid: 9808739
references.citation: Photosynth Res. 2003;75(1):11-27
references.pmid: 16245090
references.citation: Plant Cell Environ. 2010 Mar;33(3):444-52
references.pmid: 20002330
references.citation: Tree Physiol. 2003 Sep;23(13):865-77
references.pmid: 14532010
references.citation: J Exp Bot. 2010 Mar;61(5):1293-309
references.pmid: 20202998
references.citation: Planta. 1988 Apr;174(1):30-8
references.pmid: 24221414
references.citation: J Exp Bot. 2000 Feb;51 Spec No:391-7
references.pmid: 10938847
references.citation: Plant Cell Environ. 2010 Nov;33(11):1852-74
references.pmid: 20561254
references.citation: Proc Natl Acad Sci U S A. 2012 May 29;109(22):8612-7
references.pmid: 22586103
references.citation: Plant Physiol. 1984 Apr;74(4):759-65
references.pmid: 16663506
references.citation: Oecologia. 1989 Jan;78(1):9-19
references.pmid: 28311896
references.citation: Science. 2010 Aug 13;329(5993):834-8
references.pmid: 20603496
references.citation: Oecologia. 1979 Dec;44(1):68-74
references.pmid: 28310466
references.citation: J Exp Bot. 2009;60(10):2859-76
references.pmid: 19401412
references.citation: Tree Physiol. 1999 Sep;19(11):741-747
references.pmid: 12651313
references.citation: Plant Physiol. 2009 Apr;149(4):1887-95
references.pmid: 19233903
references.citation: Glob Chang Biol. 2013 Jan;19(1):45-63
references.pmid: 23504720
references.citation: Tree Physiol. 2000 May;20(9):565-578
references.pmid: 12651421
references.citation: Science. 1993 May 28;260(5112):1314-7
references.pmid: 17755426
references.citation: Biochemistry. 1969 Jun;8(6):2403-8
references.pmid: 4979056
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 20;104(47):18866-70
references.pmid: 17962418
references.citation: Plant Mol Biol. 2001 Feb;45(3):307-15
references.pmid: 11292076
references.citation: Plant Cell Environ. 2007 Mar;30(3):258-270
references.pmid: 17263773
references.citation: Plant Physiol Biochem. 2008 Mar;46(3):275-91
references.pmid: 18294858
references.citation: Planta. 1980 Jun;149(1):78-90
references.pmid: 24306196
references.citation: Biol Rev Camb Philos Soc. 2004 Aug;79(3):643-70
references.pmid: 15366766
references.citation: Annu Rev Plant Biol. 2002;53:449-75
references.pmid: 12221984
references.citation: Planta. 1968 Sep;79(3):254-67
references.pmid: 24522874
references.citation: Arch Biochem Biophys. 2003 Jun 15;414(2):150-8
references.pmid: 12781766