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Tang N, Siebers N, Leinweber P, Eckhardt KU, Dultz S, Nischwitz V, Klumpp E. Implications of Free and Occluded Fine Colloids for Organic Matter Preservation in Arable Soils. Environ Sci Technol 2022; 56:14133-14145. [PMID: 36108131 DOI: 10.1021/acs.est.2c01973] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Colloidal organo-mineral associations contribute to soil organic matter (OM) preservation and mainly occur in two forms: (i) as water-dispersible colloids that are potentially mobile (free colloids) and (ii) as building units of soil microaggregates that are occluded inside them (occluded colloids). However, the way in which these two colloidal forms differ in terms of textural characteristics and chemical composition, together with the nature of their associated OM, remains unknown. To fill these knowledge gaps, free and occluded fine colloids <220 nm were isolated from arable soils with comparable organic carbon (Corg) but different clay contents. Free colloids were dispersed in water suspensions during wet-sieving, while occluded colloids were released from water-stable aggregates by sonication. The asymmetric flow field-flow fractionation analysis on the free and occluded colloids suggested that most of the 0.6-220 nm fine colloidal Corg was present in size fractions that showed high abundances of Si, Al, and Fe. The pyrolysis-field ionization mass spectrometry revealed that the free colloids were relatively rich in less decomposed plant-derived OM (i.e., lipids, suberin, and free fatty acids), whereas the occluded colloids generally contained more decomposed and microbial-derived OM (i.e., carbohydrates and amides). In addition, a higher thermal stability of OM in occluded colloids pointed to a higher resistance to further degradation and mineralization of OM in occluded colloids than that in free colloids. This study provides new insights into the characteristics of subsized fractions of fine colloidal organo-mineral associations in soils and explores the impacts of free versus occluded colloidal forms on the composition and stability of colloid-associated OM.
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Affiliation(s)
- Ni Tang
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- Institute for Environmental Research, Biology 5, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Nina Siebers
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - Peter Leinweber
- Soil Science, Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg 6, 18051 Rostock, Germany
- Department of Life, Light, and Matter (LLM), University of Rostock, Albert-Einstein-Straße 25, 18059 Rostock, Germany
| | - Kai-Uwe Eckhardt
- Soil Science, Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-von-Liebig-Weg 6, 18051 Rostock, Germany
| | - Stefan Dultz
- Institute of Soil Science, Leibniz Universität Hannover, Herrenhäuser Straße 2, 30419 Hannover, Germany
| | - Volker Nischwitz
- Central Institute for Engineering, Electronics and Analytics, Analytics (ZEA-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
| | - Erwin Klumpp
- Institute of Bio- and Geosciences, Agrosphere (IBG-3), Forschungszentrum Jülich GmbH, Wilhelm-Johnen-Straße, 52425 Jülich, Germany
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Su J, Zhang H, Han X, Peñuelas J, Filimonenko E, Jiang Y, Kuzyakov Y, Wei C. Low carbon availability in paleosols nonlinearly attenuates temperature sensitivity of soil organic matter decomposition. Glob Chang Biol 2022; 28:4180-4193. [PMID: 35366335 DOI: 10.1111/gcb.16183] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/09/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Temperature sensitivity (Q10 ) of soil organic matter (SOM) decomposition is an important parameter in models of the global carbon (C) cycle. Previous studies have suggested that substrate quality controls the intrinsic Q10 , whereas environmental factors can impose large constraints. For example, physical protection of SOM and its association with minerals attenuate the apparent Q10 through reducing substrate availability and accessibility ([S]). The magnitude of this dampening effect, however, has never been quantified. We simulated theoretical Q10 changes across a wide range of [S] and found that the relationship between Q10 and the log10 -transformed [S] followed a logistic rather than a linear function. Based on the unique Holocene paleosol chronosequence (7 soils from ca. 500 to 6900 years old), we demonstrated that the Q10 decreased nonlinearly with soil age up to 1150 years, beyond which Q10 remained stable. Hierarchical partitioning analysis indicated that an integrated C availability index, derived from principal component analysis of DOC content and parameters reflecting physical protection and mineral association, was the main explanatory variable for the nonlinear decrease of Q10 with soil age. Microbial inoculation and 13 C-labelled glucose addition showed that low C availability induced by physical protection and minerals association attenuated Q10 along the chronosequence. A separate soil incubation experiment indicated that Q10 increased exponentially with activation energy (Ea ) in the modern soil, suggesting that SOM chemical complexity regulates Q10 only when C availability is high. In conclusion, organic matter availability strongly decreased with soil age, whereas Michelis-Menten kinetics defines the Q10 response depending on C availability, but Arrhenius equation describes the effects of increasing substrate complexity.
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Affiliation(s)
- Jiao Su
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haiyang Zhang
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, New South Wales, Australia
| | - Xingguo Han
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Josep Peñuelas
- CSIC, Global Ecology Unit CREAF-CSIC-UAB, Barcelona, Catalonia, Spain
- CREAF, Cerdanyola del Vallès, Barcelona, Catalonia, Spain
| | - Ekaterina Filimonenko
- Institute of Environmental and Agricultural Biology (X-BIO), Tyumen State University, Tyumen, Russia
| | - Yong Jiang
- College of Life Sciences, Hebei University, Baoding, China
| | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Goettingen, Göttingen, Germany
- Peoples Friendship University of Russia (RUDN University), Moscow, Russia
| | - Cunzheng Wei
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
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