caa a22 4500 605516634 CHVBK 20210128100715.0 cr unu---uuuuu 210128e20150501xx s 000 0 eng 10.1007/s10533-015-0108-1 doi (NATIONALLICENCE)springer-10.1007/s10533-015-0108-1 Amorphous silica pools in permafrost soils of the Central Canadian Arctic and the potential impact of climate change [Elektronische Daten] [Hanna Alfredsson, G. Hugelius, W. Clymans, J. Stadmark, P. Kuhry, D. Conley] We investigated the distribution, storage and landscape partitioning of soil amorphous silica (ASi) in a central Canadian region dominated by tundra and peatlands to provide a first estimate of the amount of ASi stored in Arctic permafrost ecosystems. We hypothesize that, similar to soil organic matter, Arctic soils store large amounts of ASi which may be affected by projected climate changes and associated changes in permafrost regimes. Average soil ASi storage (top 1m) ranged between 9600 and 83,500kg SiO2ha−1 among different land-cover types. Lichen tundra contained the lowest amounts of ASi while no significant differences were found in ASi storage among other land-cover types. Clear differences were observed between ASi storage allocated into the top organic versus the mineral horizon of soils. Bog peatlands, fen peatlands and wet shrub tundra stored between 7090 and 45,400kg SiO2ha−1 in the top organic horizon, while the corresponding storage in lichen tundra, moist shrub- and dry shrub tundra only amounted to 1500-1760kg SiO2ha−1. Diatoms and phytoliths are important components of ASi storage in the top organic horizon of peatlands and shrub tundra systems, while it appears to be a negligible component of ASi storage in the mineral horizon of shrub tundra classes. ASi concentrations decrease with depth in the soil profile for fen peatlands and all shrub tundra classes, suggesting recycling of ASi, whereas bog peatlands appeared to act as sinks retaining stored ASi on millennial time scales. Our results provide a conceptual framework to assess the potential effects of climate change impacts on terrestrial Si cycling in the Arctic. We believe that ASi stored in peatlands are particularly sensitive to climate change, because a larger fraction of the ASi pool is stored in perennially frozen ground compared to shrub tundra systems. A likely outcome of climate warming and permafrost thaw could be mobilization of previously frozen ASi, altered soil storage of biogenically derived ASi and an increased Si flux to the Arctic Ocean. Springer International Publishing Switzerland, 2015 Amorphous silica nationallicence Arctic nationallicence Climate change nationallicence Peatlands nationallicence Permafrost nationallicence Terrestrial Si cycle nationallicence Tundra nationallicence Alfredsson Hanna Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut Hugelius G. Department of Physical Geography, Stockholm University, Svante Arrhenius v. 8, 106 91, Stockholm, Sweden aut Clymans W. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut Stadmark J. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut Kuhry P. Department of Physical Geography, Stockholm University, Svante Arrhenius v. 8, 106 91, Stockholm, Sweden aut Conley D. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut Biogeochemistry Springer International Publishing 124/1-3(2015-05-01), 441-459 0168-2563 124:1-3<441 2015 124 10533 https://doi.org/10.1007/s10533-015-0108-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0108-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Alfredsson Hanna Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut NATIONALLICENCE 700 1- Hugelius G. Department of Physical Geography, Stockholm University, Svante Arrhenius v. 8, 106 91, Stockholm, Sweden aut NATIONALLICENCE 700 1- Clymans W. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut NATIONALLICENCE 700 1- Stadmark J. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut NATIONALLICENCE 700 1- Kuhry P. Department of Physical Geography, Stockholm University, Svante Arrhenius v. 8, 106 91, Stockholm, Sweden aut NATIONALLICENCE 700 1- Conley D. Department of Geology, Lund University, Sölvegatan 12, 223 62, Lund, Sweden aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 124/1-3(2015-05-01), 441-459 0168-2563 124:1-3<441 2015 124 10533