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Title: A global scale mechanistic model of photosynthetic capacity (LUNA V1.0)

Although plant photosynthetic capacity as determined by the maximum carboxylation rate (i.e., Vc,max25) and the maximum electron transport rate (i.e., Jmax25) at a reference temperature (generally 25 °C) is known to vary considerably in space and time in response to environmental conditions, it is typically parameterized in Earth system models (ESMs) with tabulated values associated with plant functional types. In this study, we have developed a mechanistic model of leaf utilization of nitrogen for assimilation (LUNA) to predict photosynthetic capacity at the global scale under different environmental conditions. We adopt an optimality hypothesis to nitrogen allocation among light capture, electron transport, carboxylation and respiration. The LUNA model is able to reasonably capture the measured spatial and temporal patterns of photosynthetic capacity as it explains ~55 % of the global variation in observed values of Vc,max25 and ~65 % of the variation in the observed values of Jmax25. Model simulations with LUNA under current and future climate conditions demonstrate that modeled values of Vc,max25 are most affected in high-latitude regions under future climates. In conclusion, ESMs that relate the values of Vc,max25 or Jmax25 to plant functional types only are likely to substantially overestimate future global photosynthesis.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [6] ;  [2] ;  [7] ;  [8] ;  [2] ;  [2]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of California, Irvine, CA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. National Center for Atmospheric Research, Boulder, CO (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Univ. of California, Irvine, CA (United States)
  7. California Institute of Technology, Pasadena, CA (United States)
  8. Univ. of Minnesota, St. Paul, MN (United States); Univ. of Western Sydney, New South Wales (Australia)
Publication Date:
Report Number(s):
BNL-112436-2016-JA
Journal ID: ISSN 1991-9603; KP1702010; ERKP757
Grant/Contract Number:
AC05-00OR22725; NGEE-Arctic; SC0012704
Type:
Published Article
Journal Name:
Geoscientific Model Development (Online)
Additional Journal Information:
Journal Name: Geoscientific Model Development (Online); Journal Volume: 9; Journal Issue: 2; Journal ID: ISSN 1991-9603
Publisher:
European Geosciences Union
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; carbon cycle; climate variables; leaf nitrogen optimization; model-data synthesis
OSTI Identifier:
1237866
Alternate Identifier(s):
OSTI ID: 1267038; OSTI ID: 1336062