Impact of diurnal freeze–thaw cycles on the soil nematode Scottnema lindsayae in Taylor Valley, Antarctica
- 273 Downloads
Global climate change scenarios predict not only higher temperatures, but also increased climatic variability. In cold regions, these changes may bring about a shift in the frequency of soil freeze–thaw cycles (FTCs), which represent a significant physiological challenge, especially for small, poikilothermic animals with limited mobility. To assess the impact of FTCs on cold-adapted soil biota, we evaluated freeze–thaw dynamics (i.e., 0 °C crossings) and demographics of the dominant nematode Scottnema lindsayae (proportion of adults, population size) over 20 years in soils at two locations in Taylor Valley, Antarctica. Based on hourly soil temperature data, we demonstrate that FTCs are a frequent feature in Taylor Valley, but with high inter-annual and spatial variability. Valley topography and soil moisture were found to impact FTC frequency, suggesting that basins within Taylor Valley have different susceptibilities to environmental variability. Increased FTC frequency in 1999–2001 coincided with a shift in S. lindsayae populations, with fewer juveniles reaching maturity. In the years following decreased adult proportions, overall S. lindsayae numbers were reduced, implying a strong negative effect of FTCs on in situ recruitment. Our results suggest that increased FTC frequency in the Dry Valleys slows S. lindsayae development, reducing reproductive success, and may take years to impact population size, which demonstrates the importance of long-term research to accurately predict the consequences of climate change on soil biota and biogeochemical cycling in the cold regions.
KeywordsDry Valleys Nematodes Anhydrobiosis Climate change Extreme environment Demographics Soil fauna Long-term research
This research was funded by McMurdo LTER NSF OPP Grant 1115245 to DHW, RAV, and BJA. The lab and fieldwork for this project was carried out with the indispensible help of numerous postdocs and students associated with the MCM LTER. We gratefully acknowledge the assistance of the Crary Laboratory staff, Raytheon Polar Services, and PHI Helicopters Inc. for supporting the logistical aspects of this project.
- Adhikari BN, Adams BJ (2011) Molecular analysis of desiccation survival in Antarctic nematodes. In: Perry RN, Wharton DA (eds) Molecular and physiological basis of nematode survival. CABI International, WallingfordGoogle Scholar
- Bokhorst S, Phoenix GK, Bjerke JW, Callaghan TV, Huyer-Brugman F, Berg MP (2012) Extreme winter warming events more negatively impact small rather than large soil fauna: shift in community composition explained by traits not taxa. Glob Change Biol 18:1152–1162. doi: 10.1111/j.1365-2486.2011.02565.x CrossRefGoogle Scholar
- Campbell IB, Claridge GGC, Balks MR, Campbell DI (1997) Moisture content in soils of the McMurdo sound and Dry Valley region of Antarctica. In: Lyons B, Howard-Williams C, Hawes I (eds) Ecosystem processes in Antarctic ice-free landscapes. Balkerna, RotterdamGoogle Scholar
- Fogt RL, Scambos TA (2012) Antarctica: in “state of the climate in 2011”. B Am Meteorol Soc 93:S149–S162Google Scholar
- IPCC (2013) Climate change 2013: the physical science basis. In: Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- Poage MA, Barrett JE, Virginia RA, Wall DH (2008) The influence of soil geochemistry on nematode distribution, Mcmurdo Dry Valleys, Antarctica. Arct Antarct Alp Res 40:119–128. doi: 10.1657/1523-0430%2806-051%29%5BPOAGE%5D2.0.CO%3B2 CrossRefGoogle Scholar
- R Core Team (2014) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Timm RW (1971) Antarctic soil and freshwater nematodes from the McMurdo Sound region. Proc Helminthol Soc Wash 38:42–52Google Scholar
- Wharton DA, Barclay S (1993) Anhydrobiosis in the free-living antarctic nematode Panagrolaimus davidi (Nematoda: Rhabditida). Fund Appl Nematol 16:17–22Google Scholar