From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils
<p>Permafrost-affected soils of the Arctic account for 70 % or 727 <span class="inline-formula">Pg</span> of the soil organic carbon (C) stored in the northern circumpolar permafrost region and therefore play a major role in the global C cycle. Most...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2020-07-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/17/3367/2020/bg-17-3367-2020.pdf |
| _version_ | 1819226129671651328 |
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| author | I. Prater S. Zubrzycki F. Buegger L. C. Zoor-Füllgraff G. Angst M. Dannenmann C. W. Mueller C. W. Mueller |
| author_facet | I. Prater S. Zubrzycki F. Buegger L. C. Zoor-Füllgraff G. Angst M. Dannenmann C. W. Mueller C. W. Mueller |
| author_sort | I. Prater |
| collection | DOAJ |
| description | <p>Permafrost-affected soils of the Arctic account for 70 %
or 727 <span class="inline-formula">Pg</span> of the soil organic carbon (C) stored in the
northern circumpolar permafrost region and therefore play a major role
in the global C cycle. Most studies on the budgeting of C storage and
the quality of soil organic matter (OM; SOM) in the northern circumpolar
region focus on bulk soils. Thus, although there is a plethora of
assumptions regarding differences in terms of C turnover or stability, little knowledge is available on the mechanisms stabilizing
organic C in Arctic soils besides impaired decomposition due to low
temperatures. To gain such knowledge, we investigated soils from
Samoylov Island in the Lena River delta with respect to the
composition and distribution of organic C among differently stabilized
SOM fractions. The soils were fractionated according to density and
particle size to obtain differently stabilized SOM fractions differing
in chemical composition and thus bioavailability. To better understand
the chemical alterations from plant-derived organic particles in these
soils rich in fibrous plant residues to mineral-associated SOM, we
analyzed the elemental, isotopic and chemical composition of
particulate OM (POM) and clay-sized mineral-associated OM (MAOM). We
demonstrate that the SOM fractions that contribute with about
17 <span class="inline-formula">kg C m<sup>−3</sup></span> for more than 60 % of the C stock are
highly bioavailable and that most of this labile C can be assumed to
be prone to mineralization under warming conditions. Thus, the amount
of relatively stable, small occluded POM and clay-sized MAOM that
currently accounts with about 10 <span class="inline-formula">kg C m<sup>−3</sup></span> for about
40 % of the C stock will most probably be crucial for the quantity
of C protected from mineralization in these Arctic soils in a warmer
future. Using <span class="inline-formula"><i>δ</i><sup>15</sup></span>N as a proxy for nitrogen (N) balances
indicated an important role of N inputs by biological N fixation,
while gaseous N losses appeared less important. However, this could
change, as with about 0.4 <span class="inline-formula">kg N m<sup>−3</sup></span> one third of the N is
present in bioavailable SOM fractions, which could lead to increases
in mineral N cycling and associated N losses under global warming.
Our results highlight the vulnerability of SOM in Arctic
permafrost-affected soils under rising temperatures, potentially
leading to unparalleled greenhouse gas emissions from these soils.</p> |
| first_indexed | 2024-12-23T10:20:35Z |
| format | Article |
| id | doaj.art-3c6c0e75b86a4e60a01636cb3b604b2a |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-23T10:20:35Z |
| publishDate | 2020-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-3c6c0e75b86a4e60a01636cb3b604b2a2022-12-21T17:50:41ZengCopernicus PublicationsBiogeosciences1726-41701726-41892020-07-01173367338310.5194/bg-17-3367-2020From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soilsI. Prater0S. Zubrzycki1F. Buegger2L. C. Zoor-Füllgraff3G. Angst4M. Dannenmann5C. W. Mueller6C. W. Mueller7Soil Science, Research Department Ecology and Ecosystem Management, Technical University of Munich, 85354 Freising, GermanyCenter for Earth System Research and Sustainability, School of Integrated Climate and Earth System Sciences, Universität Hamburg, 20146 Hamburg, GermanyInstitute of Biochemical Plant Pathology, Helmholtz Zentrum München GmbH, German Research Center for Environmental Health, 85764 Neuherberg, GermanySoil Science, Research Department Ecology and Ecosystem Management, Technical University of Munich, 85354 Freising, GermanyInstitute of Soil Biology and SoWa Research Infrastructure, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czech RepublicInstitute of Meteorology and Climate Research Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology, 82467 Garmisch-Partenkirchen, GermanySoil Science, Research Department Ecology and Ecosystem Management, Technical University of Munich, 85354 Freising, GermanyDepartment of Geosciences and Natural Resource Management, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark<p>Permafrost-affected soils of the Arctic account for 70 % or 727 <span class="inline-formula">Pg</span> of the soil organic carbon (C) stored in the northern circumpolar permafrost region and therefore play a major role in the global C cycle. Most studies on the budgeting of C storage and the quality of soil organic matter (OM; SOM) in the northern circumpolar region focus on bulk soils. Thus, although there is a plethora of assumptions regarding differences in terms of C turnover or stability, little knowledge is available on the mechanisms stabilizing organic C in Arctic soils besides impaired decomposition due to low temperatures. To gain such knowledge, we investigated soils from Samoylov Island in the Lena River delta with respect to the composition and distribution of organic C among differently stabilized SOM fractions. The soils were fractionated according to density and particle size to obtain differently stabilized SOM fractions differing in chemical composition and thus bioavailability. To better understand the chemical alterations from plant-derived organic particles in these soils rich in fibrous plant residues to mineral-associated SOM, we analyzed the elemental, isotopic and chemical composition of particulate OM (POM) and clay-sized mineral-associated OM (MAOM). We demonstrate that the SOM fractions that contribute with about 17 <span class="inline-formula">kg C m<sup>−3</sup></span> for more than 60 % of the C stock are highly bioavailable and that most of this labile C can be assumed to be prone to mineralization under warming conditions. Thus, the amount of relatively stable, small occluded POM and clay-sized MAOM that currently accounts with about 10 <span class="inline-formula">kg C m<sup>−3</sup></span> for about 40 % of the C stock will most probably be crucial for the quantity of C protected from mineralization in these Arctic soils in a warmer future. Using <span class="inline-formula"><i>δ</i><sup>15</sup></span>N as a proxy for nitrogen (N) balances indicated an important role of N inputs by biological N fixation, while gaseous N losses appeared less important. However, this could change, as with about 0.4 <span class="inline-formula">kg N m<sup>−3</sup></span> one third of the N is present in bioavailable SOM fractions, which could lead to increases in mineral N cycling and associated N losses under global warming. Our results highlight the vulnerability of SOM in Arctic permafrost-affected soils under rising temperatures, potentially leading to unparalleled greenhouse gas emissions from these soils.</p>https://www.biogeosciences.net/17/3367/2020/bg-17-3367-2020.pdf |
| spellingShingle | I. Prater S. Zubrzycki F. Buegger L. C. Zoor-Füllgraff G. Angst M. Dannenmann C. W. Mueller C. W. Mueller From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils Biogeosciences |
| title | From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils |
| title_full | From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils |
| title_fullStr | From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils |
| title_full_unstemmed | From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils |
| title_short | From fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soils |
| title_sort | from fibrous plant residues to mineral associated organic carbon the fate of organic matter in arctic permafrost soils |
| url | https://www.biogeosciences.net/17/3367/2020/bg-17-3367-2020.pdf |
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