![Page 1: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/1.jpg)
1
Terrestrial Ecosystem Carbon Exchange
Dr. Creighton M. Litton Department of Natural Resources and Environmental Management
University of Hawai‘i at Mānoa
• Objectives – Terrestrial Ecosystem Carbon Cycling
• Carbon Input (GPP) • Autotrophic respiration (R) • Net primary production (NPP) • Net ecosystem production (NEP) • Net Ecosystem Carbon Balance (NECB) • Belowground C flux (TBCA) • C allocation & global patterns
![Page 2: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/2.jpg)
2
• Why should we care about C cycling? – C is the energy currency of all ecosystems
• Plant (autotrophic) production is the base of almost all food/energy pyramids
• Central to all ecosystem goods & services
– Plant C cycling, to a large extent, controls atmospheric CO2 concentrations (& climate)
• ~4x as much C stored in terrestrial ecosystems as the atmosphere
• Forests account for ~50% of global terrestrial biomass and ~35% of global terrestrial productivity
– Plant-derived C fundamental to soil processes • Belowground resources are a primary control over all
ecosystem processes
Terrestrial Ecosystem Carbon Exchange
![Page 3: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/3.jpg)
3
• Terrestrial metabolism: the “breathing” of Earth
Terrestrial Ecosystem Carbon Exchange
![Page 4: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/4.jpg)
4
• C enters via photosynthesis – Gross Primary Production (GPP)
• Net photosynthesis (Gross photo - foliage R during the day)
1. Accumulates in ecosystems (C sequestration) as: (a) plant biomass; (b) SOM & microbial biomass; or (c) animal biomass
2. Returned to the atmosphere via (a) respiration (R; autotrophic or heterotrophic); (b) VOC emissions; or (c) disturbance
3. Transferred laterally to another ecosystem
Terrestrial Ecosystem Carbon Exchange
![Page 5: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/5.jpg)
5
• How do you measure GPP? – Measure photosynthesis of every leaf in the canopy?
– Measure a few leaves and scale to the canopy?
→ →
Terrestrial Ecosystem Carbon Exchange
![Page 6: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/6.jpg)
6
• How do you measure GPP? – Modeling studies
• LAI estimates from remote sensing or field studies
• APAR or FPAR • LUE from existing studies • Plug it all into a TEMs or DGVM
Terrestrial Ecosystem Carbon Exchange
![Page 7: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/7.jpg)
7
• How do you measure GPP? – Eddy flux / covariance
• CO2 sensor above the canopy – Vertical flux of CO2 is a function
of the covariance of wind velocity and gas concentration
• Really measure Net Ecosystem Exchange (NEE) – NEE = GPP - Recosystem
Terrestrial Ecosystem Carbon Exchange
![Page 8: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/8.jpg)
8
• How do you measure GPP? – Sum of individual
components • Need measurements of all
individual components • Only ~30-40 studies globally
Litton et al. (2007)
Terrestrial Ecosystem Carbon Exchange
![Page 9: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/9.jpg)
9
• What controls GPP? – Within a given set of biotic &
environmental conditions: • Leaf area
– LAI (leaf area / unit ground area; m2 m-2)
• Growing season length • Nutrient availability (esp. N) • Temperature, light, & CO2
Terrestrial Ecosystem Carbon Exchange
![Page 10: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/10.jpg)
10
• How is GPP distributed globally across biomes?
Terrestrial Ecosystem Carbon Exchange
Biomes GPP
![Page 11: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/11.jpg)
11
• Net primary production (NPP) – Net annual C gain (or
loss) by plants
– NPP = GPP – Rplant
– ANPP, ANPPwood, ANPPfoliage, BNPP, TNPP, etc.
Terrestrial Ecosystem Carbon Exchange
![Page 12: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/12.jpg)
12
• What controls NPP globally?
Terrestrial Ecosystem Carbon Exchange
Running et al. (2004)
![Page 13: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/13.jpg)
13
• How is NPP distributed globally across biomes?
Terrestrial Ecosystem Carbon Exchange
Biomes NPP
![Page 14: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/14.jpg)
14
• How is NPP distributed globally across biomes?
Terrestrial Ecosystem Carbon Exchange
Global distribution of terrestrial biomes and their total carbon in plant biomassa.
Biome
Area (106 km2) Total C pool (Pg C)
Total NPP(Pg C yr-1)
Tropical forests 17.5 340 21.9Temperate forests 10.4 139 8.1Boreal forests 13.7 57 2.6Mediterranean shrublands 2.8 17 1.4Tropical savannas andgrasslands
27.6 7914.9
Temperate grasslands 15.0 6 5.6Deserts 27.7 10 3.5Arctic tundra 5.6 2 0.5Crops 13.5 4 4.1Ice 15.5Total 149.3 652 62.6
a Data from [Roy, 2001 #3858]. Biomass is expressed in units of carbon,assuming that plant biomass is 50% carbon.• Tropical forests are ~12% of land area, but account for
~50% of global biomass and ~35% of global NPP
![Page 15: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/15.jpg)
15
• Rplant = Rgrowth + Rmaint + Rion
– What respires? • All living biomass, all the time
– Why does living biomass respire? • Grow new biomass and maintain existing biomass • Provides energy for essential metabolic processes
– Mitochondrial oxidation of CHO’s to make ATP
– Not “wasted” C
Terrestrial Ecosystem Carbon Exchange
![Page 16: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/16.jpg)
16
• Rgrowth (growth/construction) – Total C cost = C in new
biomass + C used to generate that biomass
– Varies widely by compound • Function of concentration & cost • Protein rich (leaves), structural
(wood), and defense
– How do you measure Rgrowth? • ~25% x NPP
– Total C cost = ~1.23g CHOs per 1 g of biomass produced
Terrestrial Ecosystem Carbon Exchange
![Page 17: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/17.jpg)
17
• Rmaint (maintenance of existing biomass) – Repair of non-growing tissues
• Protein turnover (~85%)
• Membrane lipids • Rion (transport across membranes)
– ≥ ½ of Rtotal
– How do you measure Rmaint? • Strongly correlated with temperature and N content
Terrestrial Ecosystem Carbon Exchange
![Page 18: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/18.jpg)
18
• Rmaint – Rm = R0(Q10)(T/10)
– Rm = 0.0106 x N content
Ryan et al. (2004)
Tw (°C)
Curtis et al. (2005)
Terrestrial Ecosystem Carbon Exchange
![Page 19: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/19.jpg)
19
• NPP = GPP - Rplant
• Typically measured on annual time scales • Units of biomass or C / unit area / unit time
• g C m-2 yr-1
• How do you measure NPP? • Remember that we typically get GPP by measuring all the components, including NPP
Terrestrial Ecosystem Carbon Exchange
![Page 20: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/20.jpg)
20
• Measuring NPP • NPP = ΔBiomass
• Biomass from allometric equations
• Need to account for biomass increment and loss because plant tissue is continually shed
• NPP = (ΔLeaf Bio. + Leaf Litter) + (ΔWood Bio. + Wood Litter) + (ΔRoot Bio. + Root Litter) • Litterfall quantified with littertraps
Terrestrial Ecosystem Carbon Exchange
Litton & Kauffman (2008)
Metrosideros polymorpha
![Page 21: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/21.jpg)
21
• Net ecosystem production (NEP) – Net annual C gain (or
loss) by an ecosystem
– NEP = GPP – Recosystem
– NEP = NPP – Rhetero
• Same as NEE???
– What are we missing?
Terrestrial Ecosystem Carbon Exchange
![Page 22: Terrestrial Ecosystem Carbon Exchangeclimate.socialsciences.hawaii.edu/Courses/GEOG402/GEOG...Deserts 27.7 10 3.5 Arctic tundra 5.6 2 0.5 Crops 13.5 4 4.1 Ice 15.5 Total 149.3 652](https://reader033.vdocuments.us/reader033/viewer/2022043003/5f81aceac96499610a7fe2f8/html5/thumbnails/22.jpg)
22
• Net Ecosystem Carbon Balance (NECB) – Net annual C gain (or
loss) by an ecosystem over long time scales
– NECB = GPP - Recosystem - Fdisturb - Fleach - Femissions
• Information most useful for C sequestration estimates
• Both natural & anthropogenic disturbances
Terrestrial Ecosystem Carbon Exchange