Degradation by drainage threatens biodiversity and globally important peatland ecosystem functions such as long-term carbon sequestration in peat. Restoration aims at safeguarding peatland values by recovering natural hydrology. Long-term effects of drainage and subsequent restoration, especially related to within-site variation of water table level and pore water chemistry, are poorly known. We studied hydrological variation at 38 boreal Sphagnum peatland sites (pristine, drained and restored) in Finland. Drainage decreased the average water table level especially near the ditches for decades and induced water chemical changes such as increased DOC concentration in peat pore water. There were also large differences in water chemistry between the samples collected from ditches and from the peat strips between the ditches. For example, the ditch water had apparently higher minerogenic influence, while DOC concentrations were highest in peat strips. Restoration was effective in regaining the natural water table level and induced a recovery of pore water chemistry towards the targeted pristine conditions. Restoration also resulted in lessened water chemical differences between ditches and peat strips indicating successful decrease of drainage-induced artificial within-site variation in water chemistry. The water table level in filled ditches was on average slightly lowered compared to surrounding areas 10 years after restoration. While such a difference may be an early warning sign for incomplete recovery of hydrology in long-term, we found no chemical evidence supporting this assumption yet. Our study suggests that restoration can result in significant recovery of peatland hydrology within 10 years, while some deviation from pristine peatlands is still typical. Restoration has a potential to reduce leaching of nutrients and DOC to downstream waters in the long term, but practitioners should be prepared for temporary increase of leaching of N and P for at least five years after restoration of boreal Sphagnum peatlands.

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Esitetään Jyväskylän yliopiston matemaattis-luonnontieteellisen tiedekunnan suostumuksella julkisesti tarkastettavaksi yliopiston vanhassa juhlasalissa S212 maaliskuun 28. päivänä 2014 kello 12.Academic dissertation to be publicly discussed, by permission of the Faculty of Mathematics and Science of the University of Jyväskylä, in building Seminarium, auditorium S212, on March 28, 2014 at 12 o'clock noon. The wide and rapidly increasing human land use has caused extensive degradation of natural landscapes, extinctions of species and loss of ecosystem functions and services. Subsequently, ecological restoration has been raised to a major global strategy for safeguarding ecosystem values. However, concerns have been raised on the real potential of restoration to re-establish ecosystem structures and functions. Here, I studied the effects of ecological restoration on the structure and functions of forestry drained boreal peatland ecosystems in southern Finland. To better understand structural and functional changes, the effects of drainage and restoration on water table level, pore water chemistry and peat chemistry were explored as well. Drainage lowered the water table and induced changes in pore water chemistry and plant community composition. Drainage retarded the accumulation of surface peat and resulted in significant reduction in the sequestration of carbon therein. Re-establishment of water table level and significant recovery of pore water and surface peat chemistry were observed after restoration. Restoration induced the recovery of ecosystem structure i.e. plant community composition towards the target. The recovery was dependent on the within-site degree of ecosystem degradation. The original ecosystem structure was not needed for the re-establishment of important peatland ecosystem functionality in terms of surface peat accumulation. However, a more profound recovery of structure and conditions may be needed for some other functions like surface peat carbon sequestration to recover. Overall, my results are promising from the perspective of restoration. However, they highlight the need for patience in drawing conclusions on the effectiveness of restoration. Practitioners should also be prepared for temporarily increased leaching of nutrients into downstream water courses. UNIVERSITY

In this study, UV-visible spectrophotometry (UV-Vis) and high-performance liquid chromatography (HPLC) were used for simultaneous analysis of chelating agents diethylenetriamine pentaacetic acid (DTPA), ethylenediamine tetraacetic acid (EDTA), and nitrilotriacetic acid (NTA), as their metal chelates in dishwashing detergents, natural waters, and pulp mill water. The total amounts of the chelating agents in dishwashing detergents were verified by potentiometric titration with Fe(III) solution. Nickel(II) chelates were determined by UV-Vis and iron(III)chelates by HPLC and titration. Recoveries of DTPA, EDTA, and NTA from a standard mixture of analytes by UV-Vis were 107+/-7, 101+/-12 and 94+/-13%, respectively, and the recovery of the total amount of complexing agents was 99+/-4%. The limits of detection for DTPA, EDTA, and NTA were 667, 324, and 739 micromol L(-1), respectively. In HPLC measurements the optimized mobile phase contained 0.03 mol L(-1) sodium acetate, 0.002 mol L(-1) tetrabutylammonium bromide, and 5% methanol at pH 3.15 and the detection was by UV-Vis detection at 254 nm. All three complexing agents could be separated from each other in a simultaneous analysis in less than 5 min. The limits of detection were 0.34, 0.27, and 0.62 micromol L(-1) for DTPA, EDTA, and NTA, respectively. The total amounts of the analytes measured in the dishwashing detergents by the three techniques were found to be highly comparable (ANOVA: F=0.04, P=0.96). R(2) values were 0.99 for EDTA, 0.99 for NTA, and 0.99 for all the results when UV-Vis and HPLC determinations were compared using regression lines. The UV-Vis and HPLC methods were proved to be viable also for analyses of natural and pulp mill waters. The absence of matrix interferences was verified by the standard addition technique.

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