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

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...

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Bibliographic Details
Published in:PloS one 2019-10, Vol.14 (10), p.e0223446
Main Authors: Laurén, Ari, Lappalainen, Mari, Kieloaho, Antti-Jussi, Karhu, Kristiina, Palviainen, Marjo
Format: Article
Language:English
Subjects:
Ambient temperature
Ammonium
Animals
Annelida - physiology
Biology and Life Sciences
Carbon
Carbon - chemistry
Carbon dioxide
Carbon Dioxide - analysis
Climate change
Climate models
Decomposition
Dissolved organic carbon
Earth Sciences
Ecology and Environmental Sciences
Ecosystem models
Ecosystems
Environment models
Environmental aspects
Environmental changes
Experiments
Feedback loops
Fluxes
Food chains
Food webs
Forests
Global warming
Health aspects
Humidity
Laboratories
Low molecular weights
Microorganisms
Mineralization
Moisture
Molecular weight
Nitrogen
Nitrogen (Chemical element)
Nitrogen - chemistry
Organic carbon
Organic Chemicals - chemistry
Organic matter
Organic nitrogen
Organic soils
Parameterization
Peat
Peatlands
Physical Sciences
Prairies
Production management
Research and Analysis Methods
Sensitivity
Soil - chemistry
Soil fauna
Soil microorganisms
Soil temperature
Soils
Storage
Temperature
Temperature effects
Worms
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Summary: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.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0223446