- CoDL Groundwater Sweden and Finland
Underground research laboratories (URL) have been constructed in geographical locations chosen for high-level radioactive waste repositories (HLRW) in Sweden and Finland. The Swedish URL is named Äspö Hard Rock Laboratory and is situated on the South East coast of Sweden about 400 km south of Stockholm. The Finnish URL is named ONKALO and is located in the Olkiluoto area on the west coast of Finland, about 300 km northwest of Helsinki. Both URLs reach about 450 m underground and they are excavated in crystalline bedrock. Both URLs reach about 450 m underground and are excavated in crystalline bed-rock. The sites have been investigated thoroughly for microbiology over a period of about 20 years. The main difference between the sites is that in Olkiluoto, there are large amounts of methane below about 300 m depth that can reach up to 1000 mL methane or more per liter of groundwater at 800 – 1000 m, while the Äspö groundwater typically have amounts of methane in the 0.1 - 5 mL L-1 range. Olkiluoto with its large amounts of methane consequently is of great interest as a deep carbon observatory. Äspö groundwater is rich in sulphate and sulphate reducing bacteria (SRB) down to 500 m and deeper, while ONKALO groundwater is almost free from sulphate and SRB at depths deeper than 350 m. General questions that we will address include: 1) Are there depth dependent distributions of diversity in Fennoscandian hard rock aquifers (both sites)? and 2) Are there differences in diversity between Äspö and the Olkiluoto/ONKALO sites (both sites)?