Decoupled responses of soil bacteria and their invertebrate consumer to warming, but not freeze–thaw cycles, in the Antarctic Dry Valleys. (10th August 2017)

• Record Type: Journal Article
• Authors: Knox, Matthew A.; Andriuzzi, Walter S.; Buelow, Heather N.; Takacs‐Vesbach, Cristina; Adams, Byron J.; Wall, Diana H.
• Editors: Fierer, Noah
• Is Part Of: Ecology letters. Volume 20:Number 10(2017)
• Page Start: 1242
• Page End: 1249
• Publication Date: 2017-08-10
• Subjects: Body size distribution -- climate change -- McMurdo Dry Valleys -- Nematode -- Scottnema lindsayae -- soil fauna -- soil microbe -- traits; Ecology -- Periodicals; 577
• DOI: 10.1111/ele.12819
• Languages: English
• ISSNs: 1461-023X

Abstract

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. FTCs and constant freezing shifted nematode body size distribution towards large individuals, driven by higher mortality among smaller individuals. FTCs 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 FTCs in cold ecosystems will select for large body size within soil microinvertebrates and overall reduce their abundance. In contrast, warm temperatures without FTCs 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.