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Albert Brangarí

Forskare

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A soil microbial model to analyze decoupled microbial growth and respiration during soil drying and rewetting

Författare

  • Albert C. Brangarí
  • Stefano Manzoni
  • Johannes Rousk

Summary, in English

Soils are continuously exposed to cycles of drying and rewetting (D/RW), which drive pronounced fluctuations in soil carbon (C) fluxes. These C dynamics are characterized by a decoupled behavior between microbial biomass synthesis (growth) and CO2 production (respiration). In general, respiration rates peak shortly after RW and subsequently decrease, while the growth peaks lag several hours behind. Despite the significance of these dynamics for the soil C budget and the global C cycle, this feature has so far been overlooked in biogeochemical models and the underlying mechanisms are still unclear. We present a new process-based soil microbial model that incorporates a wide range of physical, chemical and biological mechanisms thought to affect D/RW responses. Results show that the model is able to capture the respiration dynamics in soils exposed to repeated cycles of D/RW, and also to single events in which moisture was kept constant after RW. In addition, the model reproduces, for the first time, the responses of microbial growth to D/RW. We have identified the C accumulation during dry periods, the drought-legacy effect on the synthesis of new biomass, and osmoregulation as the strongest candidate mechanisms to explain these C dynamics. The model outputs are further compared to earlier process-based models, highlighting the advances generated by the new model. This work thus represents a step towards unravelling the microbial responses to drought and rainfall events, with implications for our understanding of C cycle and C sequestration in soils.

Avdelning/ar

  • Mikrobiologisk ekologi
  • Mikrobiell biogeokemi i Lund
  • Centrum för miljö- och klimatvetenskap (CEC)
  • BECC: Biodiversity and Ecosystem services in a Changing Climate
  • MEMEG

Publiceringsår

2020

Språk

Engelska

Publikation/Tidskrift/Serie

Soil Biology and Biochemistry

Volym

148

Dokumenttyp

Artikel i tidskrift

Förlag

Elsevier

Ämne

  • Microbiology

Nyckelord

  • Birch effect
  • Carbon dynamics
  • Carbon-use efficiency
  • Microbial mechanisms
  • Modeling
  • Moisture
  • “EcoSMMARTS” (the ecological version of a soil microbial model to account for responses to stress)

Status

Published

Projekt

  • Modelling the resilience and sustainability of soil microbial functions to climate change-induced drought in Ethiopia

Forskningsgrupp

  • Microbial Ecology
  • Microbial Biogeochemistry in Lund

ISBN/ISSN/Övrigt

  • ISSN: 0038-0717