Global Climate Change and Microorganisms

1. Global Climate Change and Microorganisms Dr. Sardar Khan Environmental Sciences

2. Global Climate Change (GCC) • Atmospheric CO2 concentration has increased globally by nearly 30% • Temperature by approximately 0.6°C, and these trends are projected to continue more rapidly (Murphy et al. 2004, Stainforth et al. 2005). • The suggested increase in mean annual surface temperature of 2-7°C by 2100 is the largest change globally (Ruess et al., 1999)

3. GCC and Environ Impacts • GCC could have significant social, economic and environmental impacts on the earth (Westerling et al. 2006). • Terrestrial ecosystems and the climate system are closely coupled through C cycling (Cao and Woodward 1998) • GCC can have significant potential impacts on the structure and function of terrestrial ecosystems (Root et al. 2003, Williams et al. 2004).

4. Gases responsible for GCC The microbial transformations generate several greenhouse gases (GHG) as by-products: • carbon dioxide (CO2, 7%), • nitrous oxide (N2O, 81%) and • methane (CH4, 87%) (IPCC, 2007). Chemo-autotrophic aerobic and an anaerobic heterotrophic microbial process

5. GCC and Microbes GCC can affect soil microbial processes by: • altering the function of microorganisms • restructuring the community, • modifying the fundamental physiologies that drive biogeochemical processes

6. Methods and Materials Microbial function/activities • Microbial biomass C, N and phosphorus (P), • Respiration, • Metabolic processes • Enzyme activity, All these can be very sensitive to GCC

7. Methods and Materials Bio-molecular techniques for microbial community structure • Culture-dependent • Culture-independent and DNA/RNA nuclear acid-based techniques • DGGE, RT-PCR • Fish and Cloning

8. Microbial Community Function and Structure and High Concentration of Atmospheric (CO2)

9. Rhizosphere

11. Enzyme activities and elevated CO2

12. N-mineralization and nitrification Austin et al., 2009 (Soil Biology and Biochemistry

13. Bacterial community structure Distribution of bacterial clones by phylum (Austin et al., 2009)

14. The Response of Soil Processes to Climate Change (Temperature and Moisture)

15. Mineralization organic matters

16. Seasonal Soil Respiration Rates and Soil Temperature

17. Relationship b/w soil respiration measurements and soil temperature measurement

18. Nematode population density and different treatment C-control, T-temperature, F-fertilizer

19. Microbial biomass C

20. Indices of the nematode community Ruess et al., 1999

21. Bacterial feeding nematodes (g-1 DW soil) Ruess et al., 1999

22. Fungal feeding nematodes

23. Conclusions • It is difficult to draw general conclusions about the full effects of elevated CO2 on terrestrial ecosystems. • Elevated (CO2) had adverse effects on microbial community structure using 16S rRNA gene clone libraries, on microbial activity measured with extracellular enzyme activity, or on soil N mineralization and nitrification rates. • Simulated climate change reduced species number, richness and diversity, and the maturity index of the nematode fauna.

24. Thank you for your attention