春季黄、渤海沉积物中CH_(4)和N_(2)O的垂向分布特征研究  

Vertical distributions of CH_(4) and N_(2)O in sediments of the Bohai and Yellow Seas in spring

作　　者：李思琦 陈烨[1,2,3] 尹霞 臧昆鹏 甄毓[2,3,4] LI Siqi;CHEN Ye;YIN Xia;ZANG Kunpeng;ZHEN Yu(College of Marine Life Science,Ocean University of China,Qingdao 266003,China;Laboratory for Marine Ecology and Environmental Science,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,China;Key Laboratory of Marine Environment and Ecology,Ministry of Education,Qingdao 266100,China;College of Environmental Science and Engineering,Ocean University of China,Qingdao 266100,China;National Marine Environmental Monitoring Center,Dalian 116023,China)

机构地区：[1]中国海洋大学海洋生命学院,山东青岛266003 [2]青岛海洋科学与技术国家实验室海洋生态与环境科学功能实验室,山东青岛266237 [3]海洋环境与生态教育部重点实验室,山东青岛266100 [4]中国海洋大学环境科学与工程学院,山东青岛266100 [5]国家海洋环境监测中心,辽宁大连116023

出　　处：《地学前缘》2022年第5期35-46,共12页Earth Science Frontiers

基　　金：国家重点研发计划项目(2017YFC1404404);国家自然科学基金项目(41620104001,41806131);青岛海洋科学与技术国家实验室鳌山科技创新计划项目(2016ASKJ02);中央高校基本科研业务费专项(202061013)。

摘　　要：本研究分别利用顶空平衡法与q PCR技术测定了2018年春季黄、渤海5个典型站位柱状沉积物中甲烷(CH_(4))和氧化亚氮(N_(2)O)浓度及产甲烷菌与硫酸盐还原菌功能基因拷贝数,并分析了其与间隙水中相关环境因子的关系。沉积物上方水文条件的差异以及其中复杂的碳氮生物地球化学过程使得CH_(4)和N_(2)O浓度呈现出明显的空间和垂直变化。结果显示,沉积物中CH_(4)浓度为0.23~0.92μmol·kg^(-1),N_(2)O浓度为18.90~104.96nmol·kg^(-1)。总体来说,渤海沉积物中CH_(4)和N_(2)O平均浓度高于黄海。垂向分布上,CH_(4)浓度均随深度增加逐渐升高,SO_(4)^(2-)浓度随深度增加逐渐降低,并与CH_(4)浓度呈镜像关系,产甲烷菌与硫酸盐还原菌的丰度也遵循着同样规律,这表明沉积物中产甲烷作用受SO_(4)^(2-)浓度的抑制。mcr A基因拷贝数平均值为渤海低于黄海。除3500-7站外,沉积物中mcr A基因拷贝数随深度增加而升高。各站位mcr A基因丰度与CH_(4)浓度均无显著相关性,且mcr A丰度与SO_(4)^(2-)浓度之间也未检测到显著相关性。dsr B基因拷贝数远高于mcr A基因拷贝数,且两者相差至少两个数量级。dsr B基因拷贝数随深度逐渐增加,直至10cm左右,随后至沉积物底部逐渐减少。各站位dsr B基因拷贝数与CH_(4)浓度剖面略有镜像关系,但均未检测到显著负相关性。以上结果均表明沉积物中存在着同时消耗沉积物中SO_(4)^(2-)与CH_(4)的其他作用。N_(2)O浓度随深度增加先降低,在深度30cm以下逐渐升高。间隙水中NO_(3)^(-)和NO_(2)^(-)浓度均随深度减小,同时NH_(4)^(+)浓度与其呈相反趋势。沉积物中N_(2)O与NO_(2)^(-)及NO_(3)^(-)浓度均呈正相关,且前者相关性较高,说明反硝化作用是沉积物中N_(2)O产生的主要过程。这些结果为进一步了解近岸陆架海域沉积物中CH_(4)和N_(2)O的来源、分布及碳氮生物地球化学循环提供了参考资料。In this study,the head-space equilibrium and quantitative PCR methods were used respectively to obtain the concentrations of methane(CH_(4))and nitrous oxide(N_(2)O)and the vertical abundances of cruises methanogens and SRB in five representative sediment cores in the Bohai and Yellow Seas during two in spring 2018.The relationships between these measurements and the related environmental parameters in vertical pore water were also analyzed.The CH_(4)and N_(2)O concentrations showed obvious spatial and variations,due to the differences in the hydrological conditions above the sediment and the complexity of carbon/nitrogen biogeochemical processes in sediment cores.The average CH_(4)and N_(2)O concentrations in nmol·kg^(-1)nmol·kg^(-1),sediments ranged between 0.23-0.92 and between 18.90-104.96 Bohai respectively,and sediments they were higher overall in the Yellow Sea than in the Sea.The CH_(4)concentrations in depth SO_(4)^(2-)concentrations the increased with increasing depth,whereas decreased steadily with methanogens as in a sulfate-mirror-image relationship with CH_(4)concentrations,while the abundances of rate and was reducing bacteria followed the same trend,indicating the CH_(4)production in sediments controlled by Bohai SO_(4)^(2-)concentration the mcr A gene the in pore water.The average copy number of was lower in the Sea than in the Yellow Sea and increased with depth at all stations except station3500-7;whilst no CH_(4)orders mcr A gene dsr B gene the significant correlation was the detected same at all stations between copy the abundance was and least SO_(4)^(2-).for concentration,and held true The number of at 2 ofmcr A gene the magnitude higher than that of the and,at all stations,increased at depths above 10 cm then between gradually decreased till copy bottom of sediments;and there was a weak mirror-image relationship negative dsr B gene the number and CH_(4)profiles at all stations,although no significant processes correlation was SO_(4)^(2-)in found between the two.The above results indicate

关 键 词：甲烷 氧化亚氮 渤海 黄海 

分 类 号：P736.21[天文地球—海洋地质] X145[天文地球—海洋科学]