Soil fungi and nutrient cycling along a gradient along soil formation at the forefield of the Damma glacier (Switzerland, Canton Uri)

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Soil fungi and nutrient cycling along a gradient
along soil formation at the forefield of the
Damma glacier (Switzerland, Canton Uri)
Monika Welc, Else Bünemann,Emmanuel Frossard, Jan
Jansa ETH Zurich, Institute of Plant Sciences,
Eschikon 33, Lindau, Switzerland
monika.welc_at_ipw.agrl.ethz.ch
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Introduction
Soil formation
Weathering of rock particles
Soil organic matter deposition and decomposition
Bacteria, fungi, fauna, plants DECOMPOSITION
TRANSFORMATION MINERALIZATION
Ectomycorrhizal fungi
Arbuscular mycorrhizal fungi
How they are involved ???
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Experimental site
Central Swiss Alps, Canton Uri
Damma glacier
1927
1850
1992
1850
Ice forehaed
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Samples preparation

• Soil samples from 0-5 cm soil profile depth
  collected on September 2007 from
• 21 sites with soil ages from 7 to 137 years
  (deglaciation chronosequence),
• 2 older sites (3000 years) as reference sites.
• Samples sieved through 2 mm sieve,
  freeze-dried and used for the phospholipid fatty
  acid (PLFA) profiling.

5 cm
5 cm
20 cm
10 cm
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Method
Based on Frostegård Bååth (1996) and
Macnaughton et al (1997)
Biomarker PLFA
- Accelerated Solvent Extractor
DCM Dichloromethane Me Methanol TLE Total
Lipid Extract NLFA Neutral Lipid Fatty Acid
ST Sterols PLFA Phospholipid Fatty Acid FAME
Fatty Acid Methyl Esters GC-MS Gas
Chromatography-Mass Spectrometry
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Preliminary results
Amount (left black axis) and number (right red
axis) of PLFA in different soils
Differences in PLFA composition expressed as
Shannon diversity index in different soils
P0.0008
P0.23
P0.01
Moraine position
Statistically significant (continuous
line)
Statistically insignificant (dashed
line)
ECM- ectomycorrhiza
AM- arbuscular mycorrhiza
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Preliminary results
Amount of biomarkers PLFA for indigenous fungi in
different soils
Biomarker fungal PLFA
Moraine position
Statistically significant (continuous
line)
Statistically insignificant (dashed
line)
P0.04
ECM- ectomycorrhiza
AM- arbuscular mycorrhiza
P0.60
- Deposition of soil organic matter favorable for
saprotrophic fungi - Later successional stages
favorable for shrubs/trees- ECM hosts - Herbs not
competitive with shrubs and trees- decrease in AM
biomarker
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Conclusions

• With increasing soil age following dependencies
  were observed
• - the number of detected PLFA increase,
• - the amount of total detected PLFA increase,
• - the diversity of PLFA not changing (Shannon
  index).
• The amount of biomarker PLFA for arbuscular
  mycorrhizal fungi show stable tendency along soil
  chronosequence, for saprotrophic/ectomycorrhizal
  fungi increase with soil age.
• Re-setting in soil development resulting from
  repeated advancements and retreats of the glacier
  can be observed.
• All observations due to successional changes.
  Fungal activity can relate to the weathering
  processes and to nutrient mobilization from soil
  and from soil organic matter via different
  strategies and in different rates.

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Open questions

• How mycorrhizal fungi and mycorrhizas involve in
  nutrient cycling and nutrient acquisition by
  different plant species and from different
  nutrients pools (inorganic, organic)?
• Dominance of certain mycorrhizal types at
  different successional stages?
• Other biomarkers employed (NLFA, ergosterol)?

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Thank you for your attention!
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Impressions from the Damma glacier forefield
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Impressions from the Damma glacier forefield
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References
Frosterård, A., Bååth, E. (1996) "The use the
phospholipid fatty acids analysis to estimate
bacterial and fungal biomass in soil". Biology
and Fertility of Soils 22 59-65.
Macnaughton, S. J., Jenkins, T., L., Alugupalli,
S. (1997). "Quantitative sampling of indoor air
biomass by signature lipid biomarker analysis
Feasibility studies in a model system". American
Industrial hygiene association Journal 58(4) 270
-277.