Abstract
Calcareous mires are peat forming systems fed by calcareous groundwater that regularly deposit travertine (CaCO3) on the soil surface or in small pools that are present in such mires. At present almost all calcareous mires in Poland are degraded, most often by land use, which has led to disturbances in local hydrological systems. An experiment was set up in a degraded spring mire in western Poland to test if travertine deposition could be restored. Trees were removed to increase surface water temperatures, and a system of open water pools was constructed to measure CaCO3 deposition in the surface water. We also studied three references systems with active CaCO3 deposition in Poland and in Latvia. The pools in the restoration site in Poland showed very little CaCO3 deposition (less than 0.2 μg · cm−2 · d−1), while the Polish reference site had significantly higher, but still modest, rates of CaCO3 deposition (ca 0.8 μg · cm−2 · d−1). At the reference sites in Latvia, we measured considerable CaCO3 deposition (up to 8 μg · cm−2 · d−1). Five years after the restoration measures in the Polish restoration site had been carried out, the vegetation showed little resemblance to the vegetation in spring systems with active calcite deposition in Poland and Latvia. Water analyses showed that the water in our restoration project was not supersaturated by calcite and had very low CO2 concentrations compared to the reference areas. The CO2 concentrations in the pool seemed a good predictor for CaCO3 deposition, better than Ca2+ concentrations. Changes in ground water flows in the source area could have been responsible for the loss of supersaturated groundwater at our restoration site. Our study showed that efforts to restore former calcareous mires can be frustrated when groundwater flow paths have been altered.
Highlights
A calcareous fen is a peat forming ecosystem that is fed by calcareous groundwater or surface water and is regularly depositing calcite on the surface of the mire
The calcium and EC values in the experimental pools were lower than those measured in pools at reference sites in Poland and Latvia
Hájek et al (2002) tried to establish a distinct border between groundwater composition and occurrence of calcareous spring mires of Central-European Carpathians mountains. They found that the minimum calcium concentration needed for occasional CaCO3 precipitation is about 2,250 μmol·l−1 and for calcite forming deposits within calcareous spring mires it is about 6,250 μmol·l−1
Summary
A calcareous fen is a peat forming ecosystem (mire) that is fed by calcareous groundwater or surface water and is regularly depositing calcite on the surface of the mire. In literature this deposited CaCO3 is sometimes called ‘marl’ or ‘calcareous tufa’, indicating the softer and clastic CaCO3 deposits in contrast to ‘travertine’, which usually refers to firmer, crystalline types of deposits. In this study we will use the term travertine as a synonym to ‘travertine-marl’, proposed by Herman and Hubbard (1990) Travertine includes both types of calcite deposition (soft and firm; see Pentecost 2005). Calcareous fens are critically endangered in most of Europe and the USA due to drainage in surrounding areas. groundwater abstraction in aquifers, eutrophication or changes in land use, such as planting pine plantations in infiltration areas (Bedford and Godwin 2003; Hájek et al 2002; Grootjans et al 2006; Middleton et al 2006)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
