The Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability

TitleThe Response of Soil CO2 Efflux to Water Limitation Is Not Merely a Climatic Issue: The Role of Substrate Availability
Publication TypeJournal Article
Year of Publication2017
Authorsde Dato G, Lagomarsino A, Lellei-Kovacs E, Liberati D, Abou Jaoude R, Marabottini R, Stazi SR, Guidolotti G, Kovacs-Lang E, Kroel-Dulay G, De Angelis P
JournalForests
Volume8
Pagination22
Date PublishedJul
Type of ArticleArticle
ISBN Number1999-4907
Accession NumberWOS:000406694400021
Keywordscarbon inputs, drought, experimental drought, Forestry, gas-exchange, Heterotrophic respiration, labile carbon, microbial community, microbial community composition, photosynthesis, precipitation regimes, respiration, response, soil CO2 efflux, substrate availability, temperature, temporal variation, use efficiency
Abstract

Water availability, together with temperature, represents the most limiting abiotic factor regulating soil CO2 efflux (SR). Besides the direct effect of water limitation, drought also influences plant activity, determining changes in the quality and quantity of root exudates, thus indirectly affecting soil microbial activity. To determine how the seasonal changes of plant activity and soil microbial metabolism and structure affect SR response to drought, we investigated the correlation between leaf gas exchange, soil carbon pools and soil respiration sources and the role of soil carbon pools on microbial populations and soil respiration, in a summer deciduous Mediterranean (SDS) and a winter deciduous temperate (WDS) shrublands, experiencing a dry summer period. In both sites, drought reduced photosynthesis, but affected SR differently: in SDS, SR decreased, although microbial heterotrophic respiration (SRh) remained unchanged; in WDS, SR did not vary but SRh was reduced. While in SDS the microbial community was able to respire more complex substrates, in WDS it was strongly dependent on easily decomposable molecules, thus on plant activity. Therefore, the response of soil CO2 efflux to water limitation is not exclusively influenced by climate as it is modulated by the degree of adaptation of the microbial community to drought.

Alternate JournalForests