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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

40104 - Soil science

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Biogeosciences

ISSN

1726-4170

e-ISSN

—

Svazek periodika

17

Číslo periodika v rámci svazku

13

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

17

Strana od-do

3367-3383

Kód UT WoS článku

000547397000001

EID výsledku v databázi Scopus

2-s2.0-85088289459