Book/Dissertation / PhD Thesis

FZJ-2018-02968

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Effects of $^{137}$Cs and $^{90}$Sr on structure and functional aspects of the microflora in agricultural used soils

Niedrée, B. (Corresponding author)FZJ*

2013
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-89336-843-3

Please use a persistent id in citations: http://hdl.handle.net/2128/18540

Abstract: At long sight $^{137}$Cs and $^{90}$Sr are the main radionuclides responsible for the contamination ofagricultural soils due to core melts in nuclear power plants such as Chernobyl or Fukushima.Once deposited on the soil surface, the two radionuclides remain in the upper soil layer forseveral decades. In the upper soil layer the highest microbial activity can be found, due tohigh organic matter contents, warm temperatures and gas exchange with the atmosphere.Hence, in contaminated soils microorganisms in upper soil layers (e.g. the plow layer onagricultural fields) are exceedingly exposed to radioactivity. However, no data are availablehow radioactive contaminations with $^{137}$Cs or $^{90}$Sr in a realistic order of magnitude affect themicrobial community and its functions in soils. This dissertation discusses the effects of radioactive contaminations on the microbial community structure and some of its functions in soils. Therefore, typical agricultural soils, an Orthic Luvisol from field site Merzenhausen and a $\textit{Gleyic Cambisol}$ from field site Kaldenkirchen-Hülst were artificially contaminated with various concentrations of $^{137}$Cs and $^{90}$Sr and partly applied with radiolabeled substrates and incubated in soil microcosms under controlled laboratory conditions. The lower radionuclide concentrations corresponded to the contaminations in the Chernobyl exclusion zone, the higher concentrations were up to 50-fold that of the maximum occurring hotspots ($^{137}$Cs) in this zone. In three experiments the effects of the ionizing radiation on the bacterial and the fungal community structure (16S and 18S rDNA DGGE), the degradation of $^{14}$C-labeled wheat straw or uniformly ring-labeled 2,4- dichlorophenoxyacetic acid, the development of the fungal biomass (ergosterol quantification) and the chemical composition of the soil organic matter ($^{13}$C CP/MAS NMR) were investigated. In half of the microcosms the soils were autoclaved and reinoculated with native soil, with intention to enhance the microbial growth. Radiation induced shifts in the microbial community structure could be observed in all experiments. Some species were directly inhibited which could be seen by a loss of bands in the DGGE gels. Other species benefited from the radiation. The loss of competitors and thus a better nutrient supply are supposed to cause these effects. However, a radiation induced impact on microbial functions could only be seen in the 2,4-D mineralization experiment. The mineralization of the uniformly $^{14}$C-ring-labeled herbicide 2,4-D was delayed for 4 days. Compared to the mineralization of wheat straw, only a limited amount of different species [...]

Keyword(s): Ackerboden ; Mikroflora ; Cäsium-137 ; Strontium-90

Note: Dissertation, Universität Bonn, 2012

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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Database coverage:

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