The roles of environmental variation and spatial distance in explaining diversity and biogeography of soil denitrifying communities in remote Tibetan wetlands

Abstract

The relative importance of local environments and dispersal limitation in shaping denitrifier community structure remains elusive. Here, we collected soils from 36 riverine, lacustrine and palustrine wetland sites on the remote Tibetan Plateau and characterized the soil denitrifier communities using high-throughput amplicon sequencing of the nirS and nirK genes. Results showed that the richness of nirS-type denitrifiers in riverine wetlands was significantly higher than that in lacustrine wetlands but not significantly different from that in palustrine wetlands. There was no clear distinction in nir community composition among the three kinds of wetlands. Irrespective of wetland type, the soil denitrification rate was positively related to the abundance, but not the α-diversity, of denitrifying communities. Soil moisture, carbon availability and soil temperature were the main determinants of diversity [operational taxonomic unit (OTU) number] and abundance of thenirS-type denitrifier community, while water total organic carbon, soil NO3– and soil moisture were important in controlling nirK-type denitrifier diversity and abundance. The nirS community composition was influenced by water electrical conductivity, soil temperature and water depth, while the nirK community composition was affected by soil electrical conductivity. Spatial distance explained more variation in the nirS community composition than in the nirK community composition. Our findings highlight the importance of both environmental filtering and spatial distance in explaining diversity and biogeography of soil nir communities in remote and relatively undisturbed wetlands.

Effects of Sea Animal Activities on Tundra Soil Denitrification and nirS‐ and nirK-Encoding Denitrifier Community in Maritime Antarctica

“…Soil pH was an important factor controlling the diversity and composition of denitrifying communities in the environments ( Saleh-Lakha et al, 2009 ; Wise et al, 2019 ). However, there were no significant correlation between pH and denitrifier diversity, nirS-encoding or nirK-encoding denitrifier community structures in tundra soils ( Supplementary Table S3 ), similar to the results in Tibetan wetlands reported by Jiang et al (2020) . Other environmental factors, such as organic carbon and nitrite, had no significant contribution to nirS and nirK-encoding denirifiers community structures in this study, although they had been reported to have significant impact on denitrifying community compositions ( Mosier and Francis, 2010 ; Francis et al, 2013 ).…”

A review on nirS-type and nirK-type denitrifiers via a scientometric approach coupled with case studies

“…In general, the majority of nirS sequences are mapped into unclassified groups or environmental clones (accounting for 38–70%), indicating that a large degree of nirS sequences are currently unavailable in the present genomic database. 52,53 Furthermore, a majority of the nirS sequences amplified with the primer set cd3aF/R3cd belonged to alpha-, beta- and gamma- proteobacteria . In soil systems, Bradyrhizobium was often found as the main nirS -type denitrifier.…”

Frequency of occurrence and habitat selection shape the spatial variation in the antibiotic resistome in riverine ecosystems in eastern China

“…Soil or sediment physicochemical properties including moisture, density, texture (i.e., the proportion of sand, silt, and clay) (hereinafter referred to as “sand”, “silt”, and “clay”), total carbon (TC), organic carbon (TOC), ammonium (NH 4 + ), nitrate (NO 3 – ), total nitrogen (TN), Ferrum (Fe), ferrous iron (Fe 2+ ), available iron (AFe), total phosphorus (P) and sulfate (SO 4 2− ) were determined in the laboratory, as described in detail in our previous work [ 31 , 32 ]. Other parameters, including pH and electric conductivity (EC), were measured using a YSI Professional Plus multi-parameter water quality meter (YSI Inc., Yellow Springs, Ohio, USA).…”

“…), nitrate (NO 3 -), total nitrogen (TN), Ferrum (Fe), ferrous iron (Fe 2+ ), available iron (AFe), total phosphorus (P) and sulfate (SO 4 2− ) were determined in the laboratory, as described in detail in our previous work [31,32]. Other parameters, including pH and electric conductivity (EC), were measured using a YSI Professional Plus multi-parameter water quality meter (YSI Inc., Yellow Springs, Ohio, USA).…”