TY - JOUR
T1 - Loss of testate amoeba functional diversity with increasing frost intensity across a continental gradient reduces microbial activity in peatlands
AU - Jassey, Vincent E.J.
AU - Lamentowicz, Mariusz
AU - Bragazza, Luca
AU - Hofsommer, Maaike L.
AU - Mills, Robert T.E.
AU - Buttler, Alexandre
AU - Signarbieux, Constant
AU - Robroek, Bjorn J.M.
PY - 2016/9
Y1 - 2016/9
N2 - 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%, >80 μm) 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.
AB - 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%, >80 μm) 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.
KW - Beta-diversity
KW - Enzymatic activity
KW - Functional turnover
KW - Mixotrophy
KW - Phenolic compounds
KW - Winter climate change
UR - http://www.scopus.com/inward/record.url?scp=84965064313&partnerID=8YFLogxK
U2 - 10.1016/j.ejop.2016.04.007
DO - 10.1016/j.ejop.2016.04.007
M3 - Article
C2 - 27161931
AN - SCOPUS:84965064313
VL - 55
SP - 190
EP - 202
JO - European Journal of Protistology
JF - European Journal of Protistology
SN - 0932-4739
IS - Part B
ER -