1. 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

2. 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

3. 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

4. Towards closing nitrogen cycle
ENIGMA development:
Yr >
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

5. 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

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

7. Leaf litter bag experiments

8. 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

9. 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

10. 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

11. 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)

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

13. 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

14. 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

15. 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