Numbers, biomass and cultivable diversity of microbial populations relate to depth and borehole-specific conditions in groundwater from depths of 4-450 m in Olkiluoto, Finland.

Microbiology, chemistry and dissolved gas in groundwater from Olkiluoto, Finland, were analysed over 3 years; samples came from 16 shallow observation tubes and boreholes from depths of 3.9-16.2 m and 14 deep boreholes from depths of 35-742 m.

Distribution, diversity and activity of microorganisms in the hyper-alkaline spring waters of Maqarin in Jordan.

The hyper-alkaline, high-Ca(2+) 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.

Occurrence and identification of microorganisms in compacted clay-based buffer material designed for use in a nuclear fuel waste disposal vault.

A full-scale nuclear fuel waste disposal container experiment was carried out 240 m below ground in an underground granitic rock research laboratory in Canada. An electric heater was surrounded by buffer material composed of sand and bentonite clay and provided heat equivalent to what is anticipated in a Canadian nuclear fuel waste repository. During the experiment, the heat caused a mass transport of water and moisture content gradients developed in the buffer ranging from 13% closest to the heater to 23% at the rock wall of the deposition hole.

Diversity and distribution of subterranean bacteria in groundwater at Oklo in Gabon, Africa, as determined by 16S rRNA gene sequencing.

This paper describes how ground water was sampled, DNA extracted, amplified and cloned and how information available in the ribosomal 16S rRNA gene was used for mapping diversity and distribution of subterranean bacteria in groundwater at the Bangombé site in the Oklo region. The results showed that this site was inhabited by a diversified population of bacteria. Each borehole was dominated by species that did not dominate in any of the other boreholes; a result that probably reflects documented differences in the geochemical environment.

Characterization of attached bacterial populations in deep granitic groundwater from the Stripa research mine by 16S rRNA gene sequencing and scanning electron microscopy.

This paper presents the molecular characterization of attached bacterial populations growing in slowly flowing artesian groundwater from deep crystalline bed-rock of the Stripa mine, south central Sweden. Bacteria grew on glass slides in laminar flow reactors connected to the anoxic groundwater flowing up through tubing from two levels of a borehole, 812-820 m and 970-1240 m. The glass slides were collected, the bacterial DNA was extracted and the 16S rRNA genes were amplified by PCR using primers matching universally conserved positions 519-536 and 1392-1405.