Bode, Samuel

Cornelis, J.-T.

Delmelle, Pierre

Doetterl, Sebastian

Van Oost, Kristof

Vermiere, M.-L.

English

OPUS Augsburg

Geophysical Research AbstractsVol. 16, EGU2014-12547-1, 2014EGU General Assembly 2014© Author(s) 2014. CC Attribution 3.0 License.Capacity of microorganisms to decompose organic carbon affected by anincreasing content of reactive mineral phases in a podzolic soilchronosequenceMarie-Liesse Vermeire (1), Sebastian Doetterl (2), Samuel Bode (2), Pierre Delmelle (1), Kristof Van Oost (3),and Jean-Thomas Cornelis (1)(1) Soil Science and Environmental Geochemistry laboratory, Earth and Life Institute , Université catholique de Louvain,Croix du Sud 2/L7.05.10, B-1348 Louvain-la-Neuve, Belgium, (2) Isotope Bioscience Laboratory (ISOFYS), Department ofApplied Analytical and Physical Chemistry, Ghent University, Coupure Links 653/Block B B.3.038, B-9000 Gent, Belgium,(3) Geography School, Earth and Life Institute - Earth and Climate, Université catholique de Louvain, Place Louis Pasteur3/L4.03.07, B-1348 Louvain-la-Neuve, BelgiumSoil organic matter stabilization has received considerable interest in the last decades due to the importance ofthe soil organic carbon (SOC) pool in the global C budget. There is increasing evidence that the formation oforgano-mineral associations play a major role in the mechanisms of organic carbon stabilization, indicating thatthe persistence of organic matter in soils relates primarily to soil physico-chemical and biological conditionsthan to intrinsic recalcitrance. Al and Fe oxy-hydroxides and short-range ordered aluminosilicates are known fortheir high capacity to sorb organic carbon. However, the impact of the evolution of these reactive mineral phasesover short time scale on the distribution of microorganisms and their ability to decompose SOC is still poorlyunderstood.To further study the short-term evolution of organo-mineral associations, we investigated a 500-year pod-zolic soil chronosequence which is characterized by an increasing amount of secondary reactive mineral phaseswith pedogenesis and soil age, and thus by increased organo-mineral associations. In order to determine the impactof these secondary mineral phases on the degradation of SOC by microorganisms, an incubation experimentwas carried out using soil horizons up to 1m deep from 6 profiles of different ages along the chronosequence.Furthermore, we used amino sugars and phospholipid fatty acids as tracers of dead and living microbial biomass,respectively, in the incubated samples.Our results show that SOC mineralization was significantly lower in the illuvial Bh/Bhs horizons (whichcontain more reactive mineral phases) compared to the surface E horizons (depleted in reactive mineral phases),although the content in amino sugars is similar in these horizons. In the deeper Bw and BC horizons, as well as inthe young profiles (<300 yrs) that have not yet undergone podzolization and related formation of organo-mineralassociations, SOC mineralization rates were the highest. These findings suggest that stabilization of OC throughorgano-mineral interactions with reactive mineral phases in our study site strongly controls the ability of microor-ganisms to decompose soil organic matter.

Capacity of microorganisms to decompose organic carbon affected by an increasing content of reactive mineral phases in a podzolic soil chronosequence

https://opus.bibliothek.uni-augsburg.de/opus4/files/87403/EGU2014-12547-1.pdf

Capacity of microorganisms to decompose organic carbon affected by an increasing content of reactive mineral phases in a podzolic soil chronosequence

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