The role of drought in the impact of climatic change on the microbiota of peatland streams

Authors


‡Author to whom correspondence should be sent

SUMMARY

1. Simulation of climate change (summer drought) stimulated autotrophy in a stream draining a Welsh peatland. Biofilm autotrophic biomass (chlorophyll) increased by 145% and was correlated with an increased overall metabolic activity (r = 0.75, P<0.05). Bacterial population densities were not significantly affected.

2. The increased autotrophy was probably related to a decrease in the organic:inorganic ratio of nutrients released from the wetland to the stream.

3. Bacterial reserves of poly-β-hydroxyalkanoate (PHA) fell by 51%. Increased nitrate concentrations were inversely correlated with autotrophic diversity (r=−0.88, P < 0.001).

4. The increased autotrophic biomass represents an increased nutrient supply for the higher trophic levels which could promote higher productivity within the stream ecosystem as a whole.

5. The simulation also caused a cooler (11%, P<0.01) streamflow from the drought-impacted wetland, which could mitigate against any adverse temperature-dependent effects of future climatic change.

Ancillary