Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze–thaw cycles, in the Antarctic Dry Valleys

• Published in: Ecology Letters
• Main Authors: Knox, Matthew A., Andriuzzi, Walter S., Buelow, Heather N., Takacs‐Vesbach, Cristina, Adams, Byron J., Wall, Diana H.
• Other Authors: Fierer, Noah, McMurdo LTER NSF OPP
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2017
• Subjects: Antarc*; Antarctic; Antarctica; McMurdo Dry Valleys
• Online Access: http://dx.doi.org/10.1111/ele.12819; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fele.12819; https://onlinelibrary.wiley.com/doi/pdf/10.1111/ele.12819

Abstract Altered temperature profiles resulting in increased warming and freeze–thaw cycle ( FTC ) frequency pose great ecological challenges to organisms in alpine and polar ecosystems. We performed a laboratory microcosm experiment to investigate how temperature variability affects soil bacterial cell numbers, and abundance and traits of soil microfauna (the microbivorous nematode Scottnema lindsayae ) from McMurdo Dry Valleys, Antarctica. FTC s and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTC s reduced both bacterial and nematode abundance, but bacterial cell numbers also declined under warming, demonstrating decoupled consumer–prey responses. We predict that higher occurrence of FTC s in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTC s could lead to divergent responses in soil bacteria and their microinvertebrate consumers, potentially affecting energy and nutrient transfer rates in soil food webs of cold ecosystems.