Demographic scenarios PIK „basic“ integrated modules: Yr 2004 CLIMBER-2 (climate + ocean carbon, CO2 as GHG) LPJ+crops (Land carbon) Climate, atm. CO2 NEP Climate CO2 emissions MIND (economy) Demographic scenarios

Demographic scenarios PIK „basic“ integrated modules: Yr 2006 CLIMBER-2 (climate + ocean carbon, all GHG, S+dust aerosols) LPJ+crops (Land carbon) MagPie: interactive Land use Climate, atm. CO2 NEP Climate Land-use mitigation options CO2 emissions MIND (economy) Demographic scenarios

ENIGMA development: Yr 2007 -> LPJ+crops (Land carbon) CLIMBER-2 (climate, GHG+aerosols, atm. chemistry – Eva Bauer in cooperation with MPI-Mainz) LPJ+crops (Land carbon) MagPie: interactive Land use Climate, atm. CO2 NEP Climate Other GHG emissions Land-use mitigation options CO2 emissions REMIND (economy) Demographic scenarios

Towards closing nitrogen cycle ENIGMA development: Yr 2007 -> Towards closing nitrogen cycle CLIMBER-2 (climate, GHG+aerosols, atm. chemistry – Eva Bauer in cooperation with MPI-Mainz) Ocean nitrogen – Hamburg? BIOME-BGC, LPJ+crops (land carbon+nitrogen) MagPie: interactive Land use Climate, atm. CO2 N depositions NEP Climate Land-use mitigation options CO2 emissions NOx emissions REMIND (economy) Demographic scenarios

Analysis of metadata on litter decomposition ENIGMA N workshop, 16 January 2007 Analysis of metadata on litter decomposition Victor Brovkin, PIK Hans Cornelissen, Free University, Amsterdam Will Cornwell, Stanford University, U.S. and Working group on litter decomposition of ARC-NZ Research Network for Vegetation Function, Macquarie University, Australia

Litter chemical and physical quality is strongly associated with decomposition Natalia Harguindeguy, pers. comm.

Leaf litter bag experiments

ART-DECO dataset: Assembly of Research on Traits and Decomposability State of 3 November 2006: number of common garden decomposition studies: 25 number of decomposition measurements (total number of harvests): 1982 number of species: 562 litter nutrient concentrations: 309 number species with litter lignin measurements: 206 A map of decomposition experiments currently in the database Cornelissen,Cornwell et al., in preparation

PFT-specific leaf litter decomposition rate in accordance with ART-DECO dataset LPJ PFT N,% C, % C:N Lignin,% Turnover rate, k(N), 1/yr tropical broadleaved evergreen tree 0.83 47 66 17 0.84 tropical broadleaved raingreen tree 1.44 48 33 14 1.23 temperate needleleaved evergreen tree 0.81 50 73 22 temperate broadleaved evergreen tree 0.78 41 21 Temperate broadleaved summergreen tree 1.41 45 1.21 boreal needleleaved evergreen tree 0.71 58 80 23 0.77 boreal needleleaved summergreen tree 0.87 57 32 0.86 boreal broadleaved summergreen tree 0.92 19 0.89 C3 perennial grass 1.24 46 1.10 C4 perennial grass 0.91 44 61

Modified litter model in LPJ Litter: 265 GtC Kg C/m2 Original LPJ Above-ground litter storage (leaf litter: PFT-specific, woody litter: PFT-nonspecific) Kg C/m2 Original LPJ Litter: 156 GtC Yr 2000, with crops

Direction to go with litter modelling Translating the decomposition rates from litter decomposition experiments on mechanistic basis (depending on litter quality - N or lignin) Upscaling from species to the PFT level Testing litter model results against available litter storage data Improving linkage between litter and soil carbon dynamics (including N, lignin)

Effect of nitrogen content of organic layers? Hakkenberg, PhD Thesis, 2006

Feedbacks with soil fertility Chapin et al. 1986 Low soil nutrient availability Slow decomposition and nutrient release Low leaf [N] + [P]; Long leaf life span; High lignin Community assembly Similar nutrient translocation Recalcitrant litter

Transplant experiment   Transplant experiment Litter half lives in years Litter from low precipitation sites is more decomposable and releases N and P faster This is a indirect effect that makes decomposition rates more similar than expected across a range of precipitation   Cornwell, PhD Thesis, 2006  

Indirect effects with aridity Low rainfall: - Community assembly Decomposition and nutrient release High leaf [N] + [P]; Low lignin + Highly decomposable litter Cornwell, PhD Thesis, 2006