Abstract
Airborne bacteria play important roles in air pollution, human health and biogeochemical cycles. However, their spatial variation and determinant factors in forest environments are poorly understood. In this study, we selected five forest types in the Liuxihe National Park, South China, to analyze how near-surface bacterial community structure is related to the forest community structure and soil physicochemical properties. The results indicated that the dominant communities were mainly constituted by seven bacterial genera of the phyla Proteobacteria (49.7%–55.4%) and Firmicutes (44.2%–49.8%), including Exiguobacterium (42.0%–46.4%), Citrobacter (20.7%–25.8%), Acinetobacter (20.1%–22.1%), and Pseudomonas (7.8%–8.9%) etc. However, differences in the composition and diversity of the airborne bacterial communities were evident among the five forests, especially with respect to the dominant taxa. The relative abundance of Enterococcus and Bacillus in coniferous and broad-leaved mixed forest (MF), broad-leaved mixed forest (BF), and pure Cunninghamia lanceolata forest (CL) was significantly higher than that of the other forests, while the relative abundance of Citrobacter was significantly lower. The relative abundance of Citrobacter, Acinetobacter, and Pseudomonas in Proteobacteria were significantly negatively correlated with plant diversity and acid phosphatase activity but positively correlated with soil pH and soil available potassium. Contrastingly, the correlation between the relative abundance of most genera of Firmicutes and the above environmental factors is just the opposite of that for Proteobacteria. We provide direct evidence that native plant communities in the middle stage of succession, compared to planted forests and forest open space, generally had higher airborne bacterial diversity. Airborne bacterial diversity showed a significantly positive correlation with plant diversity (p < 0.05). Over all, soil pH, soil available potassium, and soil available phosphorus contributed to a high rate of the diversity of the airborne bacterial community in near-surface, followed by the plant diversity of the arbor layer and the near-surface air temperature. These results extended our understanding of the ecological patterns of airborne bacteria in forest ecosystems.
Highlights
Airborne bacteria are mainly derived from natural sources such as soil, plants and water through external forces [1,2,3] and are widely distributed in the atmosphere in a suspended form that is usuallyForests 2020, 11, 561; doi:10.3390/f11050561 www.mdpi.com/journal/forestsForests 2020, 11, 561 able to adapt to atmosphere environments [4,5]
The above ten selected physicochemical characteristics, Dsh, Jt, Jsh, and leaf area index (LAI) were the representative factors of vegetation environmental factors were used for the variation partition analysis (VPA) analysis, and the results showed that the meteorological characteristics, and only air temperature (AT) was selected for the microclimate variable
The above ten selected environment, soil physicochemical properties, and vegetation characteristics jointly shaped the environmental factors were used for the VPA analysis, and the results showed that the airborne bacterial community (Figure 8)
Summary
Airborne bacteria are mainly derived from natural sources such as soil, plants and water through external forces [1,2,3] and are widely distributed in the atmosphere in a suspended form that is usuallyForests 2020, 11, 561; doi:10.3390/f11050561 www.mdpi.com/journal/forestsForests 2020, 11, 561 able to adapt to atmosphere environments [4,5]. Traveling in the wind as bio-aerosols, airborne bacteria travel long-distances across geographical barriers, link distant ecosystems [15,16], and play an essential role in the development, evolution and dynamics of ecosystems [14,17]. They absorb and reflect atmospheric radiation, which in turn directly affect the energy budget in the atmosphere [18], and ice-nuclear active bacteria act as efficient nuclei for cloud droplets, ice crystals and sediments to affect the hydrological cycle and climate [19,20,21]. Some opportunistic pathogens can spread through the air to human lungs and other organs, which can lead to infectious and allergic diseases [22,23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
