Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands

Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions due to osmotic stress, and changing temperature regimes. Using...

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Bibliographic Details
Published in:	European journal of protistology Vol. 55; no. Pt B; pp. 190 - 202
Main Authors:	Jassey, Vincent E.J., Lamentowicz, Mariusz, Bragazza, Luca, Hofsommer, Maaike L., Mills, Robert T.E., Buttler, Alexandre, Signarbieux, Constant, Robroek, Bjorn J.M.
Format:	Journal Article
Language:	English
Published:	Germany Elsevier GmbH 01-09-2016 Elsevier
Subjects:	Amoeba - physiology Beta-diversity Biodiversity Environmental Sciences Enzymatic activity Freezing Functional turnover Global Changes Mixotrophy Phenolic compounds Soil - parasitology Wetlands Winter climate change Functional turnover Winter climate change Enzymatic activity Phenolic compounds Mixotrophy Beta-diversity
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Summary:	Soil microbial communities significantly contribute to global fluxes of nutrients and carbon. Their response to climate change, including winter warming, is expected to modify these processes through direct effects on microbial functions due to osmotic stress, and changing temperature regimes. Using four European peatlands reflecting different frequencies of frost events, we show that peatland testate amoeba communities diverge among sites with different winter climates, and that this is reflected through contrasting functions. We found that exposure to harder soil frost promoted species β-diversity (species turnover) thus shifting the community composition of testate amoebae. In particular, we found that harder soil frost, and lower water-soluble phenolic compounds, induced functional turnover through the decrease of large species (−68%, >80μm) and the increase of small-bodied mixotrophic species (i.e. Archerella flavum; +79%). These results suggest that increased exposure to soil frost could be highly limiting for large species while smaller species are more resistant. Furthermore, we found that β-glucosidase enzymatic activity, in addition to soil temperature, strongly depended of the functional diversity of testate amoebae (R2=0.95, ANOVA). Changing winter conditions can therefore strongly impact peatland decomposition process, though it remains unclear if these changes are carried-over to the growing season.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0932-4739 1618-0429
DOI:	10.1016/j.ejop.2016.04.007