Padhy S R, Bhattacharyya P, Nayak S K, Dash P K, Mohapatra T
ICAR-National Rice Research Institute (NRRI), Cuttack, Odisha, India; Maharaja Sriram Chandra Bhanja Deo University, Baripada, Odisha, India.
ICAR-National Rice Research Institute (NRRI), Cuttack, Odisha, India.
Sci Total Environ. 2021 Aug 10;781:146713. doi: 10.1016/j.scitotenv.2021.146713. Epub 2021 Mar 25.
Mangrove provides significant ecosystem services, however, 40% of tropical mangrove was lost in last century due to climate change induced sea-level rise and anthropogenic activities. Sundarban-India, the largest contiguous mangrove of the world lost 10.5% of its green during 1930-2013 which primarily converted to rice-based systems. Presently degraded mangrove and adjacent rice ecology in Sundarban-India placed side by side and create typical ecology which is distinct in nature in respect to soil physicochemical properties, carbon dynamics, and microbial diversities. We investigated the structural and functional diversities of bacteria and archaea through Illumina MiSeq metagenomic analysis using V3-V4 region of 16S rRNA gene approach that drives greenhouse gases emission and carbon-pools. Remote sensing-data base were used to select the sites for collecting the soil and gas samples. The methane and nitrous oxide emissions were lower in mangrove (-0.04 mg m h and -52.8 μg m h) than rice (0.26 mg m h and 44.7 μg m h) due to less availability of carbon-substrates and higher sulphate availability (85.8% more than rice). The soil labile carbon-pools were more in mangrove, but lower microbial activities were noticed due to stress conditions. A unique microbial feature indicated by higher methanotrophs: methanogens (11.2), sulphur reducing bacteria (SRB): methanogens (93.2) ratios and lower functional diversity (7.5%) in mangrove than rice. These could be the key drivers of lower global warming potential (GWP) in mangrove that make it a green production system. Therefore, labile carbon build-up potential (38%) with less GWP (63%) even in degraded-mangrove makes it a clean production system than wetland-rice that has high potential to climate change mitigation. The whole genome metagenomic analysis would be the future research priority to identify the predominant enzymatic pathways which govern the methanogenesis and methanotrophy in this system.
红树林提供了重要的生态系统服务，然而，由于气候变化导致的海平面上升和人为活动，上个世纪40%的热带红树林消失了。印度孙德尔本斯，世界上最大的连片红树林，在1930年至2013年间其绿地面积减少了10.5%，主要转变为水稻种植系统。目前，印度孙德尔本斯退化的红树林和相邻的水稻生态系统并存，形成了一种典型的生态环境，在土壤理化性质、碳动态和微生物多样性方面具有独特的性质。我们通过使用16S rRNA基因V3-V4区域的Illumina MiSeq宏基因组分析来研究细菌和古菌的结构和功能多样性，该方法驱动温室气体排放和碳库。利用遥感数据库选择采集土壤和气体样本的地点。由于碳底物的可利用性较低和硫酸盐的可利用性较高（比水稻高85.8%），红树林中的甲烷和氧化亚氮排放量（分别为-0.04毫克/平方米·小时和-52.8微克/平方米·小时）低于水稻（分别为0.26毫克/平方米·小时和44.7微克/平方米·小时）。红树林中土壤易变碳库较多，但由于胁迫条件，微生物活性较低。红树林中甲烷氧化菌与产甲烷菌的比例较高（11.2）、硫酸盐还原菌与产甲烷菌的比例较高（93.2）以及功能多样性较低（7.5%），这些独特的微生物特征表明其与水稻不同。这些可能是红树林全球变暖潜能值较低的关键驱动因素，使其成为一个绿色生产系统。因此，即使在退化的红树林中，易变碳积累潜力（38%）和较低的全球变暖潜能值（63%）使其成为比湿地水稻更清洁的生产系统，湿地水稻在缓解气候变化方面潜力很大。全基因组宏基因组分析将是未来的研究重点，以确定控制该系统中甲烷生成和甲烷氧化的主要酶途径。
