Effects of land use, abiotic and biotic soil properties on in situ CH 4 flux in montane and subalpine forests and grasslands

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1 Effects of land use, abiotic and biotic soil properties on in situ CH 4 flux in montane and subalpine forests and grasslands Katrin M. Hofmann, Sieglinde Farbmacher and Paul Illmer Annual Conference of the ASSS 2014 Burning Issues In Soil Science

2 1. Introduction Climatic impact of CH 4 CH 4 second most important greenhouse gas after CO 2 (accounts for 20 to 30% of the global warming effect) preindustrial: 0.75 ppm today: 1.8 ppm predicted (by 2050): 2.55 ppm GWP (global warming potential) of CH 4 26 to 41 times higher compared to CO 2

3 1. Introduction Origin and fate of CH 4 sources: Tg y -1 anthropogenic and natural sources 69% biological origin (Conrad, 2009)

4 1. Introduction Methanogenesis in aerated soils methanogenic Archaea as part of anoxic food chain traditional view: methanogens restricted to anoxic habitats tolerance (catalases)? anoxic micro-niches (O 2 depletion)?

5 1. Introduction Methane oxidation in soils only biological sink for CH 4 (30 Tg y -1 ) methanotrophs use CH 4 (carbon and energy supply) α-proteobacteria, γ-proteobacteria low-affinity and high-affinity methane-oxidation

6 2. Aims determination of in situ CH 4 flux in well-aerated upland forest and grassland soils Effect of plant cover on CH 4 flux in montane and subalpine soils Effect of basement rock (calcareous vs. siliceous) Change of flux rates according to altitude physicochemical and microbiological properties of the soils are measured to embed the data into a broad biological context

7 3. Materials & Methods Soil sampling 16 forest soils, 14 grassland soils 500, 1000, 1500, and 2000 m July 2013

8 3. Materials & Methods CH 4 flux

9 3. Materials & Methods Abotic and biotic factors ph Water content organic matter (OM) C t, N t MWHC NH 4+, NO 3-, P Physicochemical factors Basal soil respiration DHA Microbial biomass (C mic ) Microbial activities and biomass

10 Methane flux [µg CH 4 m -2 h -1 ] 4. Results CH 4 flux forest -20 net consumption -40 a grassland b net emission net consumption

11 4. Results CH 4 flux Effects of land cover and altitude 0,6 1,0 Emission log Methane flux [µg CH 4 m -2 h -1 ] 0,4 0,2 0,0-0,2-0,4-0,6-0,8-1,0-1,2-1,4 log Methane flux [µg CH 4 m -2 h -1 ] 0,5 0,0-0,5-1,0-1,5 Consumption -1,6 G F -2, Land cover Altitude [m a.s.l]

12 4. Results CH 4 flux log Methane flux [µg CH 4 m -2 h -1 ] 0,1 0,0-0,1-0,2-0,3-0,4-0,5-0,6-0,7-0,8-0,9-1,0-1,1 Effect of limestone vs. silicates calcareous siliceous C S Parent material

13 4. Results a 7,5 b 0,8 ph 7,0 6,5 6,0 5,5 5,0 4,5 4,0 3,5 3,0 Organic matter [g g -1 ] 0,7 0,6 0,5 0,4 0,3 0,2 0,1 2,5 0,0 C S C S C S C cover: G land cover: F cover: G land cover: F grassland forest grassland forest S positive relationships between ph, OM and CH 4 flux

14 4. Results NH 4 + -N [µg g -1 d.w.] positive relationship between NH 4 + and CH 4 flux 0 F G F G calcareous PM: C siliceous PM: S

15 5. Summary CH 4 contributes to global warming importance of understanding regulation of flux rates collect data also from alpine regions well-aerated soils of the alpine regions are not exclusively sinks for CH 4 forest soils markedly stronger removed CH 4 altitudinal trend ph, organic matter, and NH 4 + could be involved in the regulation of CH 4 flux soils with high ph values, OM contents, and NH 4 + showed reduced capacities to act as sinks

16 Sieglinde Farbmacher Andreas Wagner Mira Mutschlechner Paul Illmer Nadine Präg

17 References Angel, R., Matthies, D., Conrad, R. (2011). Activation of methanogenesis in arid biological soil crusts despite the presence of oxygen. PloS One 6. Bomberg, M., Montonen, L., Timonen, S. (2010). Anaerobic Eury- and Crenarchaeota inhabit ectomycorrhizas of boreal forest Scots pine. European Journal of Soil Biology 46, Conrad, R. (2009). The global methane cycle. Environmental Microbiology 1, Garcia, J.-L., Patel, B.K.C., Ollivier, B. (2000). Taxonomic, phylogenetic and ecological diversity of methanogenic archaea. Anaerobe 6, IPCC, 2007: Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, Pachauri, R.K and Reisinger, A. (eds.)]. IPCC, Geneva, Switzerland, 104 pp. Madigan, M.T., Martinko, J.M., Dunlap, P.V., Clark, D.P. (2009). Brock Biology of Microorganisms. 12 th edition, Pearson Education Inc., San Francisco. Ottow, J.C.G. (2011). Mikrobiologie von Böden. Springer-Verlag, Berlin, Heidelberg.