Journal Article

Responses of soil microbial communities to water stress: results from a meta-analysis

Manzoni, Stefano, Schimel, Joshua P., Porporato, Amilcare

2012

Overview

Soil heterotrophic respiration and nutrient mineralization are strongly affected by environmental conditions, in particular by moisture fluctuations triggered by rainfall events. When soil moisture decreases, so does decomposers' activity, with microfauna generally undergoing stress sooner than bacteria and fungi. Despite differences in the responses of individual decomposer groups to moisture availability (e.g., bacteria are typically more sensitive than fungi to water stress), we show that responses of decomposers at the community level are different in soils and surface litter, but similar across biomes and climates. This results in a nearly constant soil-moisture threshold corresponding to the point when biological activity ceases, at a water potential of about −14 MPa in mineral soils and −36 MPa in surface litter. This threshold is shown to be comparable to the soil moisture value where solute diffusion becomes strongly inhibited in soil, while in litter it is dehydration rather than diffusion that likely limits biological activity around the stress point. Because of these intrinsic constraints and lack of adaptation to different hydro-climatic regimes, changes in rainfall patterns (primary drivers of the soil moisture balance) may have dramatic impacts on soil carbon and nutrient cycling.

• Publisher: Ecological Society of America
• Subject: Animal and plant ecology / Animal, plant and microbial ecology / Bacteria / Bacteria - metabolism / biogeochemical cycles / Biological activity / Biological and medical sciences / carbon / Carbon cycle / climate / Decomposition / Dehydration / Ecosystem / ecosystems / Environmental conditions / environmental factors / fauna / Forest litter / Forest soils / Fundamental and applied biological sciences. Psychology / Fungi / Fungi - metabolism / General aspects / Grassland soils / heterotrophic respiration-soil moisture relations / Litter / Meta-analysis / Microbial activity / Microbial ecology / Microbiology / Microfauna / Microorganisms / Mineral soils / Mineralization / Moisture / Moisture availability / Nutrient balance / Nutrient cycles / Nutrients / Oxygen Consumption / Rain / Rainfall / Soil analysis / Soil biology / Soil ecology / Soil Microbiology / Soil microorganisms / Soil moisture / Soil respiration / Soil water / Soils / solute diffusion / solutes / Various environments (extraatmospheric space, air, water) / Water / Water potential / Water stress