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Soil organic matter quality influences mineralization and GHG emissions in cryosols: a field‐based study of sub‐ to high A rctic
Author(s) -
Paré Maxime C.,
BedardHaughn Angela
Publication year - 2013
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.12125
Subject(s) - mineralization (soil science) , soil water , soil carbon , arctic , environmental science , soil organic matter , environmental chemistry , organic matter , ecosystem , soil science , total organic carbon , chemistry , ecology , oceanography , geology , organic chemistry , biology
Arctic soils store large amounts of labile soil organic matter ( SOM ) and several studies have suggested that SOM characteristics may explain variations in SOM cycling rates across Arctic landscapes and A rctic ecosystems. The objective of this study was to investigate the influence of routinely measured soil properties and SOM characteristics on soil gross N mineralization and soil GHG emissions at the landscape scale. This study was carried out in three C anadian A rctic ecosystems: Sub‐ A rctic ( C hurchill, MB ), Low‐ A rctic ( D aring L ake, NWT ), and High‐ A rctic ( T ruelove L owlands, NU ). The landscapes were divided into five landform units: (1) upper slope, (2) back slope, (3) lower slope, (4) hummock, and (5) interhummock, which represented a great diversity of S tatic and T urbic C ryosolic soils including B runisolic, G leysolic, and O rganic subgroups. Soil gross N mineralization was measured using the 15 N dilution technique, whereas soil GHG emissions ( N 2 O , CH 4 , and CO 2 ) were measured using a multicomponent Fourier transform infrared gas analyzer. Soil organic matter characteristics were determined by (1) water‐extractable organic matter, (2) density fractionation of SOM , and (3) solid‐state CPMAS 13 C nuclear magnetic resonance ( NMR ) spectroscopy. Results showed that gross N mineralization, N 2 O , and CO 2 emissions were affected by SOM quantity and SOM characteristics. Soil moisture, soil organic carbon ( SOC ), light fraction ( LF ) of SOM , and O ‐Alkyl‐C to Aromatic‐C ratio positively influenced gross N mineralization, N 2 O and CO 2 emissions, whereas the relative proportion of Aromatic‐C negatively influenced those N and C cycling processes. Relationships between SOM characteristics and CH 4 emissions were not significant throughout all Arctic ecosystems. Furthermore, results showed that lower slope and interhummock areas store relatively more labile C than upper and back slope locations. These results are particularly important because they can be used to produce better models that evaluate SOM stocks and dynamics under several climate scenarios and across A rctic landscapes and ecosystems.