title: Vertical Distribution of Soil Denitrifying Communities in a Wet Sclerophyll Forest under Long-Term Repeated Burning.
abstract: Soil biogeochemical cycles are largely mediated by microorganisms, while fire significantly modifies biogeochemical cycles mainly via altering microbial community and substrate availability. Majority of studies on fire effects have focused on the surface soil; therefore, our understanding of the vertical distribution of microbial communities and the impacts of fire on nitrogen (N) dynamics in the soil profile is limited. Here, we examined the changes of soil denitrification capacity (DNC) and denitrifying communities with depth under different burning regimes, and their interaction with environmental gradients along the soil profile. Results showed that soil depth had a more pronounced impact than the burning treatment on the bacterial community size. The abundance of 16S rRNA and denitrification genes (narG, nirK, and nirS) declined exponentially with soil depth. Surprisingly, the nosZ-harboring denitrifiers were enriched in the deeper soil layers, which was likely to indicate that the nosZ-harboring denitrifiers could better adapt to the stress conditions (i.e., oxygen deficiency, nutrient limitation, etc.) than other denitrifiers. Soil nutrients, including dissolved organic carbon (DOC), total soluble N (TSN), ammonium (NH(4)(+)), and nitrate (NO(3)(-)), declined significantly with soil depth, which probably contributed to the vertical distribution of denitrifying communities. Soil DNC decreased significantly with soil depth, which was negligible in the depths below 20 cm. These findings have provided new insights into niche separation of the N-cycling functional guilds along the soil profile, under a varied fire disturbance regime.
authors.affiliation: Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Nathan, QLD, 4111, Australia.
authors.forename: Xian
authors.initials: X
authors.lastname: Liu
authors.affiliation: Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Nathan, QLD, 4111, Australia. c.chen@griffith.edu.au.
authors.forename: Chengrong
authors.initials: C
authors.lastname: Chen
authors.affiliation: Science Delivery, Department of Science, Information Technology, Innovation and the Arts, 41 Boggo Road, Dutton Park, QLD, 4102, Australia.
authors.forename: Weijin
authors.initials: W
authors.lastname: Wang
authors.affiliation: Australian River Institute, and Griffith School of Environment, Griffith University, Nathan, QLD, 4111, Australia.
authors.forename: Jane M
authors.initials: JM
authors.lastname: Hughes
authors.affiliation: DAFF (Department of Agriculture, Fishery and Forestry), Horticulture and Forestry Science Agri-Science Queensland, Brisbane, 4558, Australia.
authors.forename: Tom
authors.initials: T
authors.lastname: Lewis
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China.
authors.forename: Enqing
authors.initials: E
authors.lastname: Hou
authors.affiliation: Environmental Futures Research Institute and Griffith School of Environment, Griffith University, Nathan, QLD, 4111, Australia.
authors.forename: Jupei
authors.initials: J
authors.lastname: Shen
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis; D001419:Bacteria / Q000235:genetics; D044822:Biodiversity; D002244:Carbon / Q000032:analysis; D058440:Denitrification; D017753:Ecosystem; D005390:Fires; D065928:Forests; D005798:Genes, Bacterial / Q000235:genetics; D014644:Genetic Variation; D059013:Microbial Consortia; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis; D015596:Nutrition Assessment; D010100:Oxygen / Q000009:adverse effects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology
chemical_list: D064751:Ammonium Compounds; D009566:Nitrates; D012336:RNA, Ribosomal, 16S; D012987:Soil; D002244:Carbon; D009584:Nitrogen; D010100:Oxygen
keywords: Denitrification capacity; N-cycling microbial community; Niche separation; Prescribed burning; Soil environmental factors; Soil profile