title: Gaps in knowledge and data driving uncertainty in models of photosynthesis.
abstract: Regional and global models of the terrestrial biosphere depend critically on models of photosynthesis when predicting impacts of global change. This paper focuses on identifying the primary data needs of these models, what scales drive uncertainty, and how to improve measurements. Overall, there is a need for an open, cross-discipline database on leaf-level photosynthesis in general, and response curves in particular. The parameters in photosynthetic models are not constant through time, space, or canopy position but there is a need for a better understanding of whether relationships with drivers, such as leaf nitrogen, are themselves scale dependent. Across time scales, as ecosystem models become more sophisticated in their representations of succession they needs to be able to approximate sunfleck responses to capture understory growth and survival. At both high and low latitudes, photosynthetic data are inadequate in general and there is a particular need to better understand thermal acclimation. Simple models of acclimation suggest that shifts in optimal temperature are important. However, there is little advantage to synoptic-scale responses and circadian rhythms may be more beneficial than acclimation over shorter timescales. At high latitudes, there is a need for a better understanding of low-temperature photosynthetic limits, while at low latitudes the need is for a better understanding of phosphorus limitations on photosynthesis. In terms of sampling, measuring multivariate photosynthetic response surfaces are potentially more efficient and more accurate than traditional univariate response curves. Finally, there is a need for greater community involvement in model validation and model-data synthesis.
authors: Department of Earth and Environment, Boston University, 675 Commonwealth Ave, Rm 130, Boston, MA, 02215, USA, dietze@bu.edu.
authors: Michael C
authors: MC
authors: Dietze
mesh_terms: D000064:Acclimatization; D017753:Ecosystem; D008954:Models, Biological; D008962:Models, Theoretical; D009584:Nitrogen / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D018515:Plant Leaves / Q000502:physiology; D013696:Temperature; D035501:Uncertainty
chemical_list: D009584:Nitrogen
references: Plant Cell Environ. 2010 Nov;33(11):1852-74
references: 20561254
references: Nature. 2007 Aug 16;448(7155):791-4
references: 17653194
references: Tree Physiol. 2002 Apr;22(6):393-401
references: 11960764
references: Plant Physiol. 2001 Jan;125(1):42-5
references: 11154292
references: Tree Physiol. 1987 Mar;3(1):63-91
references: 14975835
references: Plant Cell Environ. 2009 Dec;32(12):1695-709
references: 19671098
references: Trends Ecol Evol. 2008 Aug;23(8):424-31
references: 18582987
references: Curr Opin Plant Biol. 2010 Jun;13(3):233-40
references: 20552724
references: Nature. 2004 Apr 22;428(6985):821-7
references: 15103368
references: Tree Physiol. 2012 Feb;32(2):219-31
references: 22278379
references: Glob Chang Biol. 2013 Jun;19(6):1759-79
references: 23504858
references: Plant Cell Environ. 2013 Sep;36(9):1575-85
references: 23181765
references: Ecol Lett. 2011 Sep;14(9):852-62
references: 21749598
references: Curr Opin Plant Biol. 2012 Jun;15(3):228-36
references: 22284851
references: Tree Physiol. 2012 Sep;32(9):1066-81
references: 22887371
references: New Phytol. 2007;176(2):402-414
references: 17888119
references: J Exp Bot. 2003 Nov;54(392):2393-401
references: 14512377
references: Ecol Lett. 2007 Aug;10(8):647-59; discussion 659-62
references: 17594418
references: Annu Rev Plant Biol. 2009;60:357-77
references: 19575587
references: Glob Chang Biol. 2013 Jan;19(1):45-63
references: 23504720
references: Plant Physiol. 1991 Jul;96(3):831-6
references: 16668261
references: Plant Cell Environ. 2007 Sep;30(9):1176-90
references: 17661754
references: J Exp Bot. 2010 Mar;61(5):1293-309
references: 20202998
references: Planta. 1980 Jun;149(1):78-90
references: 24306196
references: Ecol Appl. 2007 Jun;17(4):1198-212
references: 17555228