Details

Autor(en) / Beteiligte

• Chen, Weibin
• Su, Fanglong
• Nie, Yanxia
• Zhong, Buqing
• Zheng, Yong
• Mo, Jiangming
• Xiong, Binghong
• Lu, Xiankai

Titel

Divergent responses of soil microbial functional groups to long-term high nitrogen presence in the tropical forests

Ist Teil von

• The Science of the total environment, 2022-05, Vol.821, p.153251-153251, Article 153251

Ort / Verlag

Netherlands: Elsevier B.V

Erscheinungsjahr

2022

Quelle

MEDLINE

Beschreibungen/Notizen

• A massive rise in atmospheric nitrogen deposition (ND) has threatened ecosystem health through accelerating soil nitrogen (N) cycling rates. While soil microbes serve a crucial function in soil N transformation, it remains poorly understood on how excess ND affects microbial functional populations regulating soil N transformation in tropical forests. To address this gap, we conducted 13-year N (as NH4NO3) addition experiments in one N-rich tropical primary forest (PF) and two N-poor tropical reforested forests (rehabilitated and disturbed) in South China. Based on our data, 13-year N introduction markedly enhanced soil N2O generation in all forests, regardless of soil N status, but microbial functional groups showed divergent responses to excess N addition among the studied forests. In the PF, long-term N introduction markedly decreased presence of bacterial 16S rRNA gene, nitrifier (amoA) and denitrifier genes (nirK, nirS and nosZ) and bacteria/fungi ratio, which could be attributed to the decreases in soil pH, dissolved organic carbon to N ratio and understory plant richness. In the two reforested forests, however, long-term N introduction generally did neither alter soil properties nor the abundance of most microbial groups. We further found that the elevated N2O generation was related to the increased soil N availability and decreased nosZ abundance, and the PF has the highest N2O generation than the other two forests. Overall, our data indicates that the baseline soil N status may dominate response of microbial functional groups to ND in tropical forests, and N-rich forests are more responsive to excess N inputs, compared to those with low-N status. Forests with high soil N status can produce more N2O than those with low-N status. With the spread of elevated ND from temperate to tropical zones, tropical forests should merit more attention because ecosystem N saturation may be common and high N2O emission will occur. [Display omitted] •N introduction increased N2O generation in all forests regardless of soil N status.•Microbial functional groups showed divergent responses to chronic high N addition.•Chronic N addition decreased presence of microbial N-cycling genes in N-rich forest.•Chronic N addition did not alter presence of most microbial groups in N-poor forest.•The decreased nosZ abundance could contributed to the increased soil N2O generation.