亚马逊热带雨林碳循环

fire hazard Volcano eruption
Human activity
● Land use patterns ● Industrial processes. ● Human life
Human factors
atmospheric CO2 concentration
source
Amazonian forests are estimated to have accumulated 0.62 ± 0.37 tons of carbon per hectare per year between 1975 and 1996
In a typical year the Amazon absorbs 1.5 *108t carbon dioxide
Positive values indicate sources
-1.5 -1.7 （sink）
negative values Indicate sinks.
3.6 ENSO to sink-source
Figure 2 Net ecosystem production across the Amazon Basin. Spatial variability in net ecosystem production (gCm-2 yr-1) in the combined simulation of transient climate and transient atmospheric CO2 during three phases of El Nino/Southern
※ red 、borrow 、yellow —source Blue、green —sink
9.6-6.2-2.2=1.2μ mols-1m-2
4、Prospect
If the earth had no ”lung”?
A 2009 study found that a 4 °C rise in global temperatures by 2100 would kill 85% of the Amazon rainforest while a temperature rise of 3 °C would kill some 75% of the Amazon. It concludes that the forest is on the brink of being turned into savanna or desert, with catastrophic consequences for the world's climate.
Southwest Amazonia，1992 to 1993[J].Science,New Series,270(5237):778-780.
[6] R. A. Houghton.et al.,2000. Annual ¯ uxes of carbon from deforestation and regrowth in the Brazilian Amazon[J].NATURE,403(20):301-304.
3.2 Modes of action
precipitation temperature
CO2
Photosynthesis
NEP
NEE NPP
Ra Rs Rh
SOC
3.3 global warming:temperature—co2 coupling
Fig. 2. Detrended anomalies of the atmospheric CO2 growth rate, tropical (24°S to 24°N) landsurface air temperature, and tropical land precipitation. The precipitation anomalies are reversed in sign for easier comparison with the CO2 growth rate and temperature. The background shading shows the occurrence and intensity of El Niño events as defined by the MEI
0.4 0.3 <0.3
பைடு நூலகம்
0.3
3.4 Temperature precipitation— NPP、Rh、NEE coupling
75%
55%
83%
3.5 Effects of global warming on terrestrial ecosystem carbon cycle.
With global warming, the ecological system NPP of low latitude area generally decreased Climate warming can increase soil respiration rate, but with the passage of time, the effect that will be more and more weak showed some adaptability Climate warming can increase land vegetation ecosystem carbon pool Climate warming can speed up the litter production, but also increase the decomposition rate of litter soil carbon of Low latitude area ecosystem still to increase due to the Supplement from the vegetation carbon pool The low latitude area performance of carbon sequestration because the vegetation carbon pool accumulation over the soil carbon release
3.1 Related concepts
NPP(net primary production) NEE(net ecosystem exchange） NEP（net ecosystem production） Rs（respiration） Ra(Autotrophic respiration) Rh（heterotrophic respiration) NPP=GPP-Rplant NEE=Rh-(GPP-Ra) NEE=Rh-NPP
medium estimate
3 The influencing factors of carbon cycle
Climatic factors
●Global warming ●El Nino and La Nina Events ● Drought
Source or sink?
Temperature precipitation interannual variations of the Nature factors
Reference
[1] M. Keller .et al.,2001. Investigating the Carbon Cycle of the Amazon Forests[J].GLOBAL CHANGE,45:15-19. [2] J.E. Richey. et al.,2001. Land Use Changes and the Biogeochemistry of River Corridors in Amazon[J]. GLOBAL CHANGE,45:19-22. [3] Hanqin Tian.et al.,1998. Effect of interannual climate Variability on carbon storage in ecosystems[J].NATURE,396:664-667. [4] Weile Wanga.et al.,2013. Variations in atmospheric CO2 growth rates coupled with tropical temperature[J]. PNAS,110(32):61-66. [5] John Grace.et al.,1995.Carbone Dioxide Uptake by an Undisturbed Tropical Rain Forest in
Amazon drainage basin
Satellite image from NASA.
2 Analysis of necessity
The Amazon represents over half of the planet's remaining rainforests,20% of the total forest area Amazonian evergreen forests account for about 10% of the world‘s terrestrial primary productivity and 10% of the carbon stores in ecosystems
[7] 徐小锋等.气候变暖对陆地生态系统碳循环的影响[J]. Journal ofPlant Ecology, 2007,31(2):175-188.
The carbon cycle of Amazon rain forest
content
Regional profile Analysis of necessity
1
2 3
The influencing factors of carbon cycle
Prospect
4
1 Regional profile
3.6 Amazon trophic forest：Source-sink?
Fig. 4.Residual carbon flux anomalies estimated by the difference between the observed atmospheric CO2 growth rate and those estimated from tropical land-surface temperature anomalies with a linear regression model
1 °C tropical temperature anomaly leading to a 3.5 ±0.6 Petagrams of carbon per year (PgC/y) CO2 growthrate anomaly on average
0.7 0.5
(Multivariate ENSO Index)
2.1 biomass in Brazilian Amazonia
forests recovered 70% of their original biomass in 25 years and the remaining 30% over the next 50 years
Figure 1 The spatial distribution of biomass in Brazilian Amazonia. a, RADAMBRASIL wood volumes converted to biomass with equations from refs 18, 19 (low estimate). b, RADAMBRASIL volumes converted to biomass (from ref. 21) (high estimate). c, Biomass interpolated from 56 sites (medium estimate).