Distribution, diversity and activity of microorganisms in the hyper-alkaline spring waters of Maqarin in Jordan
Artikel i vetenskaplig tidskrift, 2004

The hyper-alkaline, high-Ca2+ springs of Maqarin, Jordan, were investigated as an analogue for various microbial processes at the extremely high pH generated by cement and concrete in some underground radioactive waste repositories. Leaching of metamorphic, cementitious phases in Maqarin has produced current, hyper-alkaline groundwater with a maximum pH of 12.9. Six consecutive expeditions were undertaken to the area during 1994–2000. The total number of microorganisms in the alkaline waters was 103–105 cells/ml. Analysis of the 16S-ribosomal ribonucleic acid (rRNA) diversity revealed microorganisms mainly belonging to the Proteobacteria. Obvious similarities between the obtained sequences and sequences from other alkaline sites could not be found. Numerous combinations of culture media compositions were inoculated with spring, seepage and groundwaters and incubated under aerobic and anaerobic conditions with various carbon sources. Assimilation studies were performed using identical radio-labeled carbon sources. Glucose seemed to be the preferred carbon source for assimilation, followed by acetate, lactate, and leucine. The results demonstrate that microorganisms from the hyper-alkaline springs of Maqarin could grow and be metabolically active under aerobic and anaerobic hyper-alkaline conditions. However, the growth and activity found were not vigorous; instead, slow growth, low numbers, and a generally low metabolic activity were found. This suggests that microbial activity will be low during the hyper-alkaline phase of cementitious repositories

Proteobacteria

16S-rRNA sequencing

Seepage

Radioactive waste

High-calcium alkaline environment

Groundwater

Författare

Karsten Pedersen

Göteborgs universitet

Emma Nilsson

Göteborgs universitet

Johanna Arlinger

Göteborgs universitet

Lotta Hallbeck

Göteborgs universitet

Andrew O'Neill

Extremophiles

1431-0651 (ISSN) 1433-4909 (eISSN)

Vol. 8 151-164

Ämneskategorier

Annan biologi

DOI

10.1007/s00792-004-0374-7