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| Titel |
Climate effect on soil enzyme activities and dissolved organic carbon in mountain calcareous soils: a soil-transplant experiment |
| VerfasserIn |
Jérémy Puissant, Lauric Cécillon, Robert T. E. Mills, Konstantin Gavazov, Bjorn J. M. Robroek, Thomas Spiegelberger, Alexandre Buttler, Jean-Jacques Brun |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250081518
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| Zusammenfassung |
| Mountain soils store huge amounts of carbon as soil organic matter (SOM) which may be
highly vulnerable to the strong climate changes that mountain areas currently experience
worldwide. Climate modifications are expected to impact microbial activity which could
change the rate of SOM decomposition/accumulation, thereby questioning the net C
source/sink character of mountain soils. To simulate future climate change expected in the
21st century in the calcareous pre-Alps, 15 blocks (30 cm deep) of undisturbed soil were
taken from a mountain pasture located at 1400 m a.s.l. (Marchairuz, Jura, Switzerland) and
transplanted into lysimeters at the same site (control) and at two other sites located at 1000 m
a.s.l. and 600 m a.s.l. (5 replicates per site). This transplantation experiment which
started in 2009 simulates a climate warming with a temperature increase of 4Ë C
and a decreased humidity of 40 % at the lowest site. In this study, we used soil
extracellular enzyme activities (EEA) as functional indicators of SOM decomposition to
evaluate the effect of climate change on microbial activity and SOM dynamics along
the seasons. Dissolved organic carbon (DOC) was also measured to quantify the
assimilable carbon for microorganism. In autumn 2012, a first sampling step out of four
(winter, spring and summer 2013) has been realized. We extracted 15 cm deep
soil cores from each transplant (x15) and measured (i) DOC and (ii) the activities
of nine different enzymes. Enzymes were chosen to represent the degradation of
the most common classes of biogeochemical compounds in SOM. β-glucosidase,
β-D-cellubiosidase, β-Xylosidase, N-acetyl-β-glucosaminidase, leucine aminopeptidase,
lipase, phenoloxidase respectively represented the degradation of sugar, cellulose,
hemicellulose, chitin, protein, lipid and lignin. Moreover, the fluorescein diacetate (FDA)
hydrolysis was used to provide an estimate of global microbial activity and phosphatase
was used to estimate phosphorus mineralization. The autumn results showed no
differences for global microbial activity along the climate gradient (0.37 nKatal g-1
dry soil), no differences and a very low activity for leucine aminopeptidase and
β-glucosidase and β-Xylosidase (about 0.09 nKatal g-1 dry soil) and no differences for
cellulose, chitin and phosphorus mineralization. Conversely, we measured a greater
activity at the highest elevation site for lipase and phenoloxydase (ANOVA test,
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