Hydrogeochemical conditions and evolution at the Äspö HRL, Sweden

Laaksoharju, Marcus; Tullborg, Eva‐Lena; Wikberg, Peter; Wallin, B.; Smellie, J.A.T.

doi:10.1016/s0883-2927(99)00023-2

Cited by 102 publications

(63 citation statements)

References 18 publications

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“…Viable numbers of SRB and phages The water around the Ä spö HRL tunnel at a depth below 250 m is ancient anaerobic glacial water and seawater that has been subsurface for B10 000 years (Laaksoharju et al, 1999). The sampled groundwater contained sulphate of 313-659 mg l -1 and sulphide of 0.006-2.01 mg l -1 concentrations (Table 1), which suggested that microbial sulphate reduction was ongoing.…”

Section: Discussionmentioning

confidence: 99%

“…Along the walls of the tunnel, groundwater-containing fractures are intersected by boreholes with packed-off borehole sections that could be accessed through valves and tubes. The age and origin of the water surrounding the tunnel have been modelled from geochemical data and were shown to correlate generally with salinity (Laaksoharju et al, 1999). The water was found to be heterogeneously distributed at different depths: water down to a depth of B250 m was dominated by meteoric freshwater, unlike water from depths of 250 to 600 m, which consisted of brackish-saline water with mixing proportions of current and ancient Baltic Sea water and meltwater from the last glaciation event B10 000 years ago (Supplementary information gives more details).…”

Section: Methodsmentioning

confidence: 99%

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Bacteriophage lytic to Desulfovibrio aespoeensis isolated from deep groundwater

et al. 2009

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Viruses were earlier found to be 10-fold more abundant than prokaryotes in deep granitic groundwater at the Ä spö Hard Rock Laboratory (HRL). Using a most probable number (MPN) method, 8-30 000 cells of sulphate-reducing bacteria per ml were found in groundwater from seven boreholes at the Ä spö HRL. The content of lytic phages infecting the indigenous bacterium Desulfovibrio aespoeensis in Ä spö groundwater was analysed using the MPN technique for phages. In four of 10 boreholes, 0.2À80 phages per ml were found at depths of 342-450 m. Isolates of lytic phages were made from five cultures. Using transmission electron microscopy, these were characterized and found to be in the Podoviridae morphology group. The isolated phages were further analysed regarding host range and were found not to infect five other species of Desulfovibrio or 10 Desulfovibrio isolates with up to 99.9% 16S rRNA gene sequence identity to D. aespoeensis. To further analyse phage-host interactions, using a direct count method, growth of the phages and their host was followed in batch cultures, and the viral burst size was calculated to be B170 phages per lytic event, after a latent period of B70 h. When surviving cells from infected D. aespoeensis batch cultures were inoculated into new cultures and reinfected, immunity to the phages was found. The parasite-prey system found implies that viruses are important for microbial ecosystem diversity and activity, and for microbial numbers in deep subsurface groundwater.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Bacteriophage lytic to Desulfovibrio aespoeensis isolated from deep groundwater

et al. 2009

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“…It has significant implications for the geological disposal of high-level radioactive waste (HLW) originating from nuclear power plants (Banwart and Gustafsson 1994;Gascoyne et al 1995;Laaksoharju et al 1999;Thury and Bossart 1999;Flint et al 2001;Cai and Kaiser 2005;Carrera 2005, 2006;Joyce et al 2010), long-term engineering and environmental effects of tunnels (Ii and Kagami 1997;Sato et al 2000;Cesano et al 2000;Vales et al 2004;Yang et al 2008;Font-Capo et al 2012), and following the construction of underground storage facilities and mines (Younger 2000;Maejima et al 2003;Lee et al 2003;Bauer et al 2013;Lee et al 2014). The selection of a disposal site for HLW, for instance, takes into consideration the geological environment at depths of hundreds of meters assessed by various surface-based investigations.…”

Section: Introductionmentioning

confidence: 99%

“…However, the construction and operation of a large underground facility, such as an HLW repository, could lead to changes in the geological environment on the timescale of tens to hundreds of years, which impacts the suitability of the selected disposal site. For example, previous studies in the Aspo Hard Rock Laboratory, Sweden, showed that hydraulic disturbances occurred in the crystalline rock (Grenier et al 2009), leading to a drawdown of the groundwater level by tens of meters and the penetration of tritium containing groundwater into the laboratory (Laaksoharju et al 1999;Mahara et al 2001). Another case of groundwater level drawdown was observed at the Underground Research Laboratory in Manitoba, Canada, where 60 m drawdown of the groundwater level occurred around two shafts in the Lac du Bonnet granite batholith over a 25-year period of construction and operation at a depth of more than 420 m. Groundwater inflow along fractures and faults intersected by the shafts leads to the mixing of distinctly different saline groundwaters and significantly changes the water chemistry (Priyanto et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Hydrochemical disturbances measured in groundwater during the construction and operation of a large-scale underground facility in deep crystalline rock in Japan

et al. 2015

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Changes in the hydrochemical conditions of groundwater were evaluated following the construction of a large-scale underground facility at the Mizunami Underground Research Laboratory (MIU), Japan. The facility was constructed to a depth of 500 m in sedimentary and granitic rocks. Drawdown of the groundwater level in the range of several tens to hundreds of meters was observed up to hundreds of meters away from the shafts during the first ten years of facility construction and operation. Subsequent changes in groundwater chemistry occurred due to upconing of high-salinity groundwater from the deepest part of the shaft and the infiltration of low-salinity shallow groundwater. We predict that future deep groundwater chemistry in the vicinity of the MIU facility will resemble that of the present-day shallow groundwater. Multivariate statistical analysis provides fundamental insights into such a site. We found that the extent of hydrochemical variability related to MIU construction and operation was dependent on the distance from the facility shafts and galleries and on hydrogeological compartmentalization resulting from lithological boundaries (such as permeable conglomerates vs. more compact lithological units) and other features (such as faults or clay layers). We conclude that hydrochemical impact assessment of groundwater in low-permeability rock is essential prior to the construction of such a facility. This should include characterization of hydrogeological structures and compartments to propose suitable location of shafts and galleries.

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“…Because the pore fluid velocities in these settings are slow, these subsurface communities probably originated by entrapment during burial of the microbial.communities that established themselves at and just below the sediment-water interface. The microbial communities occurring at 200 to 400 mbls along fractures in Precambrian granite in Sweden probably originated from the intrusion of glacial meltwaters during the last deglaciation at 7000 BP [Laaksoharju et al, 1995]. In Cretaceous aquifers of the eastern United States, where bacterial colonies have been found at 200-400 mbls [Balkwill, 1989], the pore fluid velocities range from 4 to 90 rn/yr [Murphy et al, 1992].…”

Section: Introductionmentioning

confidence: 99%

Hydrogeologic Constraint on the origin of deep subsurface microorganisms within a Triassic Basin

Tseng¹,

Person²,

Onstott³

1998

Water Resources Research

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Abstract. The thermal history of the Taylorsville basin indicates that the thermophilic anaerobic bacteria extracted from Triassic strata at 2800 m below the land surface within the basin probably migrated to their current location. In order to ascertain the most probable scenario for microbial transport, a two-dimensional transient fluid flow and heat transport model of the Taylorsville basin was developed using the finite element method. The numerical model was constrained by tectonic and thermal histories of the basin, coupled with the permeability and porosity data extracted from core samples. The model demonstrates that a topographically driven groundwater flow system, caused by the tectonic uplift and erosion during the Jurassic, can explain the observed differential cooling of the basin. The computed groundwater flow rates during this period were on the order of 1 to 100 mm/yr. Combined with the cooling history of the microbially sampled strata, such rates provided a possible mechanism for the introduction of ancient surface or subsurface microorganisms to the deep subsurface. This tectogenetic mechanism may explain the origins of deep subsurface microorganisms for other regions of the Earth.

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Hydrogeochemical conditions and evolution at the Äspö HRL, Sweden

Cited by 102 publications

References 18 publications

Bacteriophage lytic to Desulfovibrio aespoeensis isolated from deep groundwater

Bacteriophage lytic to Desulfovibrio aespoeensis isolated from deep groundwater

Hydrochemical disturbances measured in groundwater during the construction and operation of a large-scale underground facility in deep crystalline rock in Japan

Hydrogeologic Constraint on the origin of deep subsurface microorganisms within a Triassic Basin

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