Drainage enhances modern soil carbon contribution but reduces old soil carbon contribution to ecosystem respiration in tundra ecosystems.

Autor: Kwon MJ; Max Planck Institute for Biogeochemistry, Jena, Germany.; Korea Polar Research Institute, Incheon, South Korea., Natali SM; Woods Hole Research Center, Falmouth, Massachusetts., Hicks Pries CE; Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California.; Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire., Schuur EAG; Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona., Steinhof A; Max Planck Institute for Biogeochemistry, Jena, Germany., Crummer KG; Department of Biology, University of Florida, Gainesville, Florida., Zimov N; North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia., Zimov SA; North-East Science Station, Pacific Institute for Geography, Far-Eastern Branch of Russian Academy of Science, Chersky, Republic of Sakha (Yakutia), Russia., Heimann M; Max Planck Institute for Biogeochemistry, Jena, Germany.; Division of Atmospheric Sciences, Department of Physics, Helsinki University, Helsinki, Finland., Kolle O; Max Planck Institute for Biogeochemistry, Jena, Germany., Göckede M; Max Planck Institute for Biogeochemistry, Jena, Germany.
Jazyk: angličtina
Zdroj: Global change biology [Glob Chang Biol] 2019 Apr; Vol. 25 (4), pp. 1315-1325. Date of Electronic Publication: 2019 Feb 25.
DOI: 10.1111/gcb.14578
Abstrakt: Warming temperatures are likely to accelerate permafrost thaw in the Arctic, potentially leading to the release of old carbon previously stored in deep frozen soil layers. Deeper thaw depths in combination with geomorphological changes due to the loss of ice structures in permafrost, may modify soil water distribution, creating wetter or drier soil conditions. Previous studies revealed higher ecosystem respiration rates under drier conditions, and this study investigated the cause of the increased ecosystem respiration rates using radiocarbon signatures of respired CO 2 from two drying manipulation experiments: one in moist and the other in wet tundra. We demonstrate that higher contributions of CO 2 from shallow soil layers (0-15 cm; modern soil carbon) drive the increased ecosystem respiration rates, while contributions from deeper soil (below 15 cm from surface and down to the permafrost table; old soil carbon) decreased. These changes can be attributed to more aerobic conditions in shallow soil layers, but also the soil temperature increases in shallow layers but decreases in deep layers, due to the altered thermal properties of organic soils. Decreased abundance of aerenchymatous plant species following drainage in wet tundra reduced old carbon release but increased aboveground plant biomass elevated contributions of autotrophic respiration to ecosystem respiration. The results of this study suggest that drier soils following drainage may accelerate decomposition of modern soil carbon in shallow layers but slow down decomposition of old soil carbon in deep layers, which may offset some of the old soil carbon loss from thawing permafrost.
(© 2019 John Wiley & Sons Ltd.)
Databáze: MEDLINE
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