From fibrous plant residues to mineral-associated organic carbon the fate of organic matter in Arctic permafrost soils

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60077344%3A_____%2F20%3A00531642" target="_blank" >RIV/60077344:_____/20:00531642 - isvavai.cz</a>

Result on the web

<a href="https://bg.copernicus.org/articles/17/3367/2020/bg-17-3367-2020.pdf" target="_blank" >https://bg.copernicus.org/articles/17/3367/2020/bg-17-3367-2020.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.5194/bg-17-3367-2020" target="_blank" >10.5194/bg-17-3367-2020</a>

Result language

angličtina

Original language name

From fibrous plant residues to mineral-associated organic carbon the fate of organic matter in Arctic permafrost soils

Original language description

Permafrost-affected soils of the Arctic account for 70% or 727 Pg 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 mineralassociated SOM, we analyzed the elemental, isotopic and chemical composition of particulate OM (POM) and claysized mineral-associated OM (MAOM). We demonstrate that the SOM fractions that contribute with about 17 kgCm-3 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 claysized MAOM that currently accounts with about 10 kgCm-3 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 δ15N 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 kgNm-3 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.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

40104 - Soil science

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Biogeosciences

ISSN

1726-4170

e-ISSN

—

Volume of the periodical

17

Issue of the periodical within the volume

13

Country of publishing house

DE - GERMANY

Number of pages

17

Pages from-to

3367-3383

UT code for WoS article

000547397000001

EID of the result in the Scopus database

2-s2.0-85088289459