Research On Anaerobic Methane Oxidation Dominated By Archaea In Intertidal Ecosystem

The intertidal ecosystem plays an important role in the carbon and nitrogen cycle of marine ecosystems,and have great amount of organic material,which can be decomposed by microorganisms under anaerobic conditions to produce large amounts of methane and inorganic nitrogenous.It was thought that methane was mainly removed by SAMO process in marine ecosystem,the SAMO process are dominated by ANMEs and SRB jointly,while other anaerobic methane oxidation processes has long been neglected.As we all know,the bacteria belong to the NC10 phylum(M.oxyfera and M.sinica)can couple ANMO to nitrite reduction through N-DAMO process.In addition,the archaea belong to ANME-2d,which was named M.nitroreducens can also couple ANMO to nitrate reduction through Nr-D AMO process.The ANMEs and ANME-2d archaea are widely distributed in natural habitats,however,there are little research about the distribution and activity of ANMEs and ANME-2d archaea in intertidal ecosystem.In this paper,the abundance,diversity,community structure,activity and related environmental factors of ANMEs and ANME-2d in the intertidal ecosystem of Zhoushan Island were investigated.The main results are presented as follows:1.The abundance,diversity,community structure,activity and related environmental factors of ANME-2d in the intertidal ecosystem of Zhoushan Island were revealed.1)Stable isotope experiments showed that the potential Nr-DAMO activity in intertidal sediments collected from Zhoushan Island was 0-1.57 nmol 13CO2 g-1(dry sediment)day-1.The contribution rate of the Nr-DAMO process during the anaerobic methane oxidation process were 22.3%to 60.6%,indicating that the Nr-DAMO process is an important sink of methane that has long been neglected in the intertidal ecosystem.2)Phylogenetic analyses of the recovered 16S rRNA gene sequences showed that the intertidal sediments collected from Zhoushan Island contained high diversity level of ANME-2d archaea.Quantitative PCR showed that the abundance of ANME-2d archaea in the intertidal sediments were 4.34�104-1.18�105 copies g-1(dry sediment).3)Pearson moment correlation analysis and RDA analysis showed that NO3-and SO42-were two main environmental factors which could significantly impact the diversity of ANME-2d archaea and the potential Nr-DAMO activity.2.The abundance,diversity,community structure,activity and related environmental factors of ANMEs archaea in the intertidal ecosystem of Zhoushan Island were revealed.1)Stable isotope experiments showed that the potential SAMO activity dominated by ANMEs archaea was 0-0.77 nmol 13CO2 g-1(dry sediment)day-1,accounts for about 34.5%of potential total anaerobic methane oxidation activity,indicating that the SAMO process is an important sink of methane that could not be neglected in the intertidal ecosystem.2)Quantitative PCR and Illumina-based 16S rRNA gene sequencing showed that there were great amounts of ANMEs archaea in the intertidal sediments collected from Zhoushan Island.The abundance of ANMEs archaea were 9.10�105-1.13�107 copies(g dry sediment)-1.The high diversity level of ANMEs archaea was determined by the unique environmental conditions of the intertidal ecosystem.3)Pearson moment correlation analysis and RDA analysis showed that T,ORP,SO42-and TOM were main environmental factors which could significantly impact the abundance and community structure of ANMEs archaea and the potential SAMO activity.3.The abundance,diversity,community structure,activity and related environmental factors of ANME-2d and ANMEs archaea in the simulated soil columns ecosystem were revealed.1)Stable isotope experiments showed that the potential Nr-DAMO activity and the potential SAMO activity in the soil samples collected from three simulated soil columns were 0.16-1.49 13CO2 g-1(dry sediment)day-1 and 0.00-2.78 13CO2 g-1(dry sediment)day-1 respectively.The contribution rate of the Nr-DAMO process and the SAMO process during the anaerobic methane oxidation process were 21.28%-56.15%and 19.90%-53.12%respectively,indicating that the Nr-DAMO and the SAMO process were very important for methane removal in the simulated soil columns ecosystem.2)Quantitative PCR and lllumina-based 16S rRNA gene sequencing showed that there were large amounts of ANME-2d and ANMEs archaea in the soil samples collected from three simulated soil columns.The abundance of ANMEs and ANME-2d archaea were 1.11�106-2.13�107 copies(g dry sediment)-1 and 1.07�104-2.60�105 copies(g dry sediment)-1 respectively.Oxygen was the main environmental factor which could significantly impact the abundance and diversity of ANME-2d and ANMEs archaea.3)Pearson moment correlation analysis and RDA analysis showed that the simulated soil columns experiments proved that in intertidal ecosystem,oxygen,SO42-,NO3-and TOM were main environmental factors which could significantly impact the abundance,activity and community structure of ANMEs and ANME-2d archaea in the simulated soil columns ecosystem.