Predicting climate change impacts on maritime Antarctic soils: a space-for-time substitution study

Horrocks, C.A., Newsham, K.K., Cox, F., Garnett, M.H. , Robinson, C.,H., and Dungait, J.A.J. (2020) Predicting climate change impacts on maritime Antarctic soils: a space-for-time substitution study. Soil Biology and Biochemistry, 141, 107682. (doi: 10.1016/j.soilbio.2019.107682)

Abstract

We report a space-for-time substitution study predicting the impacts of climate change on vegetated maritime Antarctic soils. Analyses of soils from under Deschampsia antarctica sampled from three islands along a 2,200 km climatic gradient indicated that those from sub-Antarctica had higher moisture, organic matter and carbon (C) concentrations, more depleted δ13C values, lower concentrations of the fungal biomarker ergosterol and higher concentrations of bacterial PLFA biomarkers and plant wax n-alkane biomarkers than those from maritime Antarctica. Shallow soils (2 cm depth) were wetter, and had higher concentrations of organic matter, ergosterol and bacterial PLFAs, than deeper soils (4 cm and 8 cm depths). Correlative analyses indicated that factors associated with climate change (increased soil moisture, C and organic matter concentrations, and depleted δ13C contents) are likely to give rise to increases in Gram negative bacteria, and decreases in Gram positive bacteria and fungi, in maritime Antarctic soils. Bomb-14C analyses indicated that sub-Antarctic soils at all depths contained significant amounts of modern 14C (C fixed from the atmosphere post c. 1955), whereas modern 14C was restricted to depths of 2 cm and 4 cm in maritime Antarctica. The oldest C (c. 1,745 years BP) was present in the southernmost soil. The higher nitrogen (N) concentrations and δ15N values recorded in the southernmost soil were attributed to N inputs from bird guano. Based on these analyses, we conclude that 5–8 °C rises in air temperature, together with associated increases in precipitation, are likely to have substantial impacts on maritime Antarctic soils, but that, at the rates of climate warming predicted under moderate greenhouse gas emission scenarios, these impacts are likely to take at least a century to manifest themselves.

• Item Type: Articles
• Additional Information: This research was funded by an Antarctic Funding Initiative grant and associated awards from the UK Natural Environment Research Council (grant numbers NE/H014098/1, NE/H014772/1 and NE/H01408X/1) and a NERC Radiocarbon Facility NRCF010001 allocation (1690.0313).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Garnett, Dr Mark
• Authors: Horrocks, C.A., Newsham, K.K., Cox, F., Garnett, M.H., Robinson, C.,H.,, and Dungait, J.A.J.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Soil Biology and Biochemistry
• Publisher: Elsevier
• ISSN: 0038-0717
• ISSN (Online): 1879-3428
• Published Online: 20 November 2019
• Copyright Holders: Copyright © 2019 The Authors
• First Published: First published in Soil Biology and Biochemistry 141: 107682
• Publisher Policy: Reproduced under a Creative Commons License