TY  - JOUR
A1  - Reverey, Florian
A1  - Ganzert, Lars
A1  - Lischeid, Gunnar
A1  - Ulrich, Andreas
A1  - Premke, Katrin
A1  - Grossart, Hans-Peter
T1  - Dry-wet cycles of kettle hole sediments leave a microbial and biogeochemical legacy
JF  - The science of the total environment : an international journal for scientific research into the environment and its relationship with man
N2  - Understanding interrelations between an environment's hydrological past and its current biogeochemistry is necessary for the assessment of biogeochemical and microbial responses to changing hydrological conditions. The question how previous dry-wet events determine the contemporary microbial and biogeochemical state is addressed in this study. Therefore, sediments exposed to the atmosphere of areas with a different hydrological past within one kettle hole, i.e. (1) the predominantly inundated pond center, (2) the pond margin frequently desiccated for longer periods and (3) an intermediate zone, were incubated with the same rewetting treatment. Physicochemical and textural characteristics were related to structural microbial parameters regarding carbon and nitrogen turnover, i.e. abundance of bacteria and fungi, denitrifiers (targeted by the nirK und nirS functional genes) and nitrate ammonifiers (targeted by the nrfA functional gene). Our study reveals that, in combination with varying sediment texture, the hydrological history creates distinct microbial habitats with defined boundary conditions within the kettle hole, mainly driven by redox conditions, pH and organic matter (OM) composition. OM mineralization, as indicated by CO2-outgassing, was most efficient in exposed sediments with a less stable hydrological past. The potential for nitrogen retention via nitrate ammonification was highest in the hydrologically rather stable pond center, counteracting nitrogen loss due to denitrification. Therefore, the degree of hydrological stability is an important factor leaving a microbial and biogeochemical legacy, which determines carbon and nitrogen losses from small lentic freshwater systems in the long term run.
KW  - Desiccation
KW  - DNRA
KW  - Denitrifiers
KW  - Organic matter mineralization
KW  - Carbon
KW  - Nitrogen
Y1  - 2018
U6  - https://doi.org/10.1016/j.scitotenv.2018.01.220
SN  - 0048-9697
SN  - 1879-1026
VL  - 627
SP  - 985
EP  - 996
PB  - Elsevier
CY  - Amsterdam
ER  -