Midot Frazer, Goh Kian Mau, Liew Kok Jun, Lau Sharon Yu Ling, Espenberg Mikk, Mander Ülo, Melling Lulie
Sarawak Tropical Peat Research Institute, Kota Samarahan, Sarawak, Malaysia.
Faculty of Science, Universiti Teknologi Malaysia, Skudai, Johor, Malaysia.
Appl Environ Microbiol. 2025 Jan 31;91(1):e0198624. doi: 10.1128/aem.01986-24. Epub 2024 Dec 23.
Tropical peatlands significantly influence local and global carbon and nitrogen cycles, yet they face growing pressure from anthropogenic activities. Land use changes, such as peatland forests conversion to oil palm plantations, affect the soil microbiome and greenhouse gas (GHG) emissions. However, the temporal dynamics of microbial community changes and their role as GHG indicators are not well understood. This study examines the dynamics of peat chemistry, soil microbial communities, and GHG emissions from 2016 to 2020 in a logged-over secondary peat swamp forest in Sarawak, Malaysia, which transitioned to an oil palm plantation. This study focuses on changes in genetic composition governing plant litter degradation, methane (CH), and nitrous oxide (NO) fluxes. Soil CO emission increased (doubling from approximately 200 mg C m h), while CH emissions decreased (from 200 µg C m h to slightly negative) following land use changes. The NO emissions in the oil palm plantation reached approximately 1,510 µg N m h, significantly higher than previous land uses. The CH fluxes were driven by groundwater table, humification levels, and C:N ratio, with populations dominating methanogenesis and as the main CH oxidizer. The NO fluxes correlated with groundwater table, total nitrogen, and C:N ratio with dominant -type denitrifiers (13-fold to ) and a minor role by nitrification (a threefold increase in ) in the plantation. and encoding incomplete denitrification genes potentially impact NO emissions. These findings highlighted complex interactions between microbial communities and environmental factors influencing GHG fluxes in altered tropical peatland ecosystems.IMPORTANCETropical peatlands are carbon-rich environments that release significant amounts of greenhouse gases when drained or disturbed. This study assesses the impact of land use change on a secondary tropical peat swamp forest site converted into an oil palm plantation. The transformation lowered groundwater levels and changed soil properties. Consequently, the oil palm plantation site released higher carbon dioxide and nitrous oxide compared to previous land uses. As microbial communities play crucial roles in carbon and nitrogen cycles, this study identified environmental factors associated with microbial diversity, including genes and specific microbial groups related to nitrous oxide and methane emissions. Understanding the factors driving microbial composition shifts and greenhouse gas emissions in tropical peatlands provides baseline information to potentially mitigate environmental consequences of land use change, leading to a broader impact on climate change mitigation efforts and proper land management practices.
热带泥炭地对当地和全球的碳氮循环有着重大影响，但它们正面临着来自人类活动日益增加的压力。土地利用变化，如将泥炭地森林转变为油棕种植园，会影响土壤微生物群落和温室气体（GHG）排放。然而，微生物群落变化的时间动态及其作为温室气体指标的作用尚未得到充分了解。本研究调查了2016年至2020年期间马来西亚砂拉越一片已砍伐的次生泥炭沼泽森林（该森林已转变为油棕种植园）中泥炭化学、土壤微生物群落和温室气体排放的动态变化。本研究重点关注控制植物凋落物降解、甲烷（CH₄）和一氧化二氮（N₂O）通量的基因组成变化。土地利用变化后，土壤CO₂排放增加（从约200毫克碳每平方米每小时翻倍），而CH₄排放减少（从200微克碳每平方米每小时降至略为负值）。油棕种植园中的N₂O排放达到约1510微克氮每平方米每小时，显著高于先前的土地利用情况。CH₄通量受地下水位、腐殖化程度和碳氮比驱动，其中某类菌群主导甲烷生成，而另一类菌群为主要的CH₄氧化菌。N₂O通量与地下水位、总氮和碳氮比相关，种植园中占主导的某类反硝化菌（数量增加13倍）起主要作用，硝化作用的影响较小（数量增加三倍）。编码不完全反硝化基因的某两类菌群可能影响N₂O排放。这些发现突出了微生物群落与环境因素之间复杂的相互作用，这些因素影响着热带泥炭地生态系统变化过程中的温室气体通量。
重要性
热带泥炭地是富含碳的环境，在排水或受到干扰时会释放大量温室气体。本研究评估了土地利用变化对一个转变为油棕种植园的次生热带泥炭沼泽森林地点的影响。这种转变降低了地下水位并改变了土壤性质。因此，与先前的土地利用情况相比，油棕种植园地点释放了更多的二氧化碳和一氧化二氮。由于微生物群落在碳氮循环中发挥着关键作用，本研究确定了与微生物多样性相关的环境因素，包括与一氧化二氮和甲烷排放相关的基因和特定微生物群。了解驱动热带泥炭地微生物组成变化和温室气体排放的因素，可为潜在减轻土地利用变化的环境后果提供基线信息，从而对减缓气候变化的努力和适当的土地管理实践产生更广泛的影响。
