TY - JOUR

T1 - How vegetation patches drive soil development and organic matter formation on polar islands

AU - Prater, Isabel

AU - Hrbáček, Filip

AU - Braun, Christina

AU - Vidal, Alix

AU - Meier, Lars Arne

AU - Nývlt, Daniel

AU - Mueller, Carsten W.

N1 - Funding Information: We are grateful for the funding within the DFG Priority Programme 1158 “Antarctic Research with Comparable Investigations in Arctic Sea Ice Areas” ( MU 3021/8-1 ). The work of FH and DN has been supported by the Ministry of Education, Youth and Sports of the Czech Republic projects no. LM2015078 (Czech Polar Research Infrastructure), and CZ.02.1.01/0.0/0.0/16_013/0001708 (Ecopolaris). The work of CB in the field season 2016/2017 has been supported by the German Federal Environment Agency (UBA) under the grant agreement UFOPLAN 3715 19 213 0 , logistics support was provided by Russian Antarctic Expedition, Aerovías DAP and Antarctica XXI. We thank Maria Greiner for her assistance with physical soil fractionation and elemental analyses. Publisher Copyright: © 2021 Elsevier B.V.

PY - 2021/12

Y1 - 2021/12

N2 - As Antarctica is strongly affected by climate change and global warming, the factors that mainly determine soil development might also shift from the dominance of physical to biochemical processes. Vegetation is restricted to the margins of the Antarctic continent with the Antarctic Peninsula being a region of patchily distributed vegetation. While on James Ross Island in the Weddell Sea only cryptogams can be found, on King George Island in the Southern Ocean also vascular plants are present. As rates of soil development and the build-up of soil organic matter are very low in these polar conditions, it can be hypothesized that vegetation patches comprise hot spots for biogeochemical soil processes. To analyze the effect of vegetation on soils in maritime Antarctica, we investigated vegetated and vegetation-free soils from both islands. On both islands, we found clearly higher carbon and nitrogen contents in vegetated soils. Using physical fractionation, we could demonstrate that the amount of free and occluded particulate organic matter is also higher in soils under vegetation, but at the same time, that clay-sized mineral-associated organic matter contributes most to carbon storage in all soils. The dominance of aromatic compounds in vegetation-free soils was disclosed by 13C NMR spectroscopy as well as a larger proportion of compounds with a lower molecular weight in vegetated soils. Thus, vegetation patches lead to soil organic matter containing higher amounts of bioavailable substrates that can be assumed to foster microbial activity and thus drive further soil development in a warmer future. However, in the cold arid environments a propagation of aridity might result in vegetation dieback and thus in a ceasing of biological soil activity driving a slowing of soil development.

AB - As Antarctica is strongly affected by climate change and global warming, the factors that mainly determine soil development might also shift from the dominance of physical to biochemical processes. Vegetation is restricted to the margins of the Antarctic continent with the Antarctic Peninsula being a region of patchily distributed vegetation. While on James Ross Island in the Weddell Sea only cryptogams can be found, on King George Island in the Southern Ocean also vascular plants are present. As rates of soil development and the build-up of soil organic matter are very low in these polar conditions, it can be hypothesized that vegetation patches comprise hot spots for biogeochemical soil processes. To analyze the effect of vegetation on soils in maritime Antarctica, we investigated vegetated and vegetation-free soils from both islands. On both islands, we found clearly higher carbon and nitrogen contents in vegetated soils. Using physical fractionation, we could demonstrate that the amount of free and occluded particulate organic matter is also higher in soils under vegetation, but at the same time, that clay-sized mineral-associated organic matter contributes most to carbon storage in all soils. The dominance of aromatic compounds in vegetation-free soils was disclosed by 13C NMR spectroscopy as well as a larger proportion of compounds with a lower molecular weight in vegetated soils. Thus, vegetation patches lead to soil organic matter containing higher amounts of bioavailable substrates that can be assumed to foster microbial activity and thus drive further soil development in a warmer future. However, in the cold arid environments a propagation of aridity might result in vegetation dieback and thus in a ceasing of biological soil activity driving a slowing of soil development.

KW - C NMR spectroscopy

KW - Antarctic Peninsula

KW - James Ross Island

KW - King George Island

KW - Mineral-associated organic matter

KW - Particulate organic matter

KW - Vegetation-soil interaction

U2 - 10.1016/j.geodrs.2021.e00429

DO - 10.1016/j.geodrs.2021.e00429

M3 - Journal article

AN - SCOPUS:85113758573

VL - 27

JO - Geoderma Regional

JF - Geoderma Regional

SN - 2352-0094

M1 - e00429

ER -