1. Temperature sensitivity patterns of carbon and nitrogen processes in decomposition of boreal organic soils - Quantification in different compounds and molecule sizes based on a multifactorial experiment
- Author
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Laurén, Ari, Lappalainen, Mari, Kieloaho, Antti-Jussi, Karhu, Kristiina, Palviainen, Marjo, Department of Forest Sciences, Soils and climate change, Forest Soil Science and Biogeochemistry, Forest Ecology and Management, Ecosystem processes (INAR Forest Sciences), and Institute for Atmospheric and Earth System Research (INAR)
- Subjects
Atmospheric Science ,Topography ,Ecological Metrics ,Nitrogen ,Climate Change ,Annelida ,Science ,Marine and Aquatic Sciences ,Ultrafiltration ,Forests ,Research and Analysis Methods ,Ecosystems ,Greenhouse Gases ,Soil ,Specimen Storage ,Q10 Temperature Coefficient ,Environmental Chemistry ,Animals ,Organic Chemicals ,Climatology ,Landforms ,Decomposition ,4112 Forestry ,Ecology ,Ecology and Environmental Sciences ,Chemical Compounds ,Chemical Reactions ,Temperature ,Biology and Life Sciences ,Aquatic Environments ,Geomorphology ,Humidity ,Carbon Dioxide ,Terrestrial Environments ,Carbon ,Chemistry ,Separation Processes ,Atmospheric Chemistry ,Wetlands ,Storage and Handling ,Physical Sciences ,1181 Ecology, evolutionary biology ,Earth Sciences ,Medicine ,Filtration ,Research Article ,Freshwater Environments - Abstract
Climate warming and organic matter decomposition are connected in a recursive manner; this recursion can be described by temperature sensitivity. We conducted a multifactorial laboratory experiment to quantify the temperature sensitivity of organic carbon (C) and nitrogen (N) decomposition processes of common boreal organic soils. We incubated 36 mor and 36 slightly decomposed Carex-Sphagnum peat samples in a constant moisture and ambient temperature for 6 months. The experiment included three temperature and two moisture levels and two food web manipulations (samples with and without fungivore enchytraeid worms). We determined the release of carbon dioxide (CO2) and dissolved organic carbon (DOC) in seven molecular size classes together with ammonium N and dissolved organic N in low molecular weight and high molecular weight fractions. The temperature sensitivity function Q10 was fit to the data. The C and N release rate was almost an order of magnitude higher in mor than in peat. Soil fauna increased the temperature sensitivity of C release. Soil fauna played a key role in N release; when fauna was absent in peat, the N release was ceased. The wide range of the studied C and N compounds and treatments (68 Q10 datasets) allowed us to recognize five different temperature sensitivity patterns. The most common pattern (37 out of 68) was a positive upwards temperature response, which was observed for CO2 and DOC release. A negative downward pattern was observed for extractable organic nitrogen and microbial C. Sixteen temperature sensitivity patterns represented a mixed type, where the Q10function was not applicable, as this does not allow changing the sign storage change rate with increasing or decreasing temperature. The mixed pattern was typically connected to intermediate decomposition products, where input and output fluxes with different temperature sensitivities may simultaneously change the storage. Mixed type was typical for N processes. Our results provide useful parameterization for ecosystem models that describe the feedback loop between climate warming, organic matter decomposition, and productivity of N-limited vegetation.
- Published
- 2019