| 摘要: |
| 海沟是全球大洋体系的重要组成部分。研究这一极端环境的生物地球化学循环过程有助于我们进一步理解海洋的物质循环。前期研究发现，海沟表层水体的初级生产力（NPP）对海沟沉积物埋藏的有机碳性质具有重要影响，但是，颗粒有机碳（POC）在沉降过程中被微生物呼吸和降解的过程尚不清楚。因此，本研究利用2018年春“太阳号”阿塔卡马海沟（Atacama Trench）国际联合航次SO261所采集的表层水样品，测试其中POC浓度、C/N、δ13C、δ15N等参数，并结合0.2—0.8、0.8—3.0、>3.0 μm三种粒径微生物群落呼吸（microbial community respiration，MCR）速率测试，探究其日变化模式及不同站位的空间变化模式，进而衡量微生物对POC的呼吸降解作用。结果表明，该海域表层水中对POC降解占主导作用的微生物类群粒径为0.8—3.0 μm；24 h时间序列实验表明MCR随时间呈现“M”型曲线的双峰变化模式，且和C/N、δ13C、δ15N等参数变化趋势吻合，表明同一站位的呼吸速率主要与光强有关，并对代谢有机碳的元素性质产生影响；在空间上，海沟站位表层的MCR显著大于非海沟站位，并受初级生产力的影响。最后，本文计算得到表层水微生物对NPP的呼吸降解比例在0.5%—4.6%之间。 |
| 关键词: 阿塔卡马海沟 颗粒有机碳 表层水体 呼吸作用 时空变化 |
| DOI：10.11693/hyhz20200600163 |
| 分类号: |
| 基金项目:国家自然科学基金，41806085号，42076029号；欧盟委员会基金，ERC669947号；深圳市科技创新委员会基金，GJHZ20180928155004783号，ZDSYS20180208184349083号；南方海洋科学与工程广东省实验室（广州），GML2019ZD0210号。 |
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| TEMPORAL AND SPATIAL DISTRIBUTION OF PARTICULATE ORGANIC CARBON AND MICROBIAL COMMUNITY RESPIRATION OF ATACAMA TRENCH SURFACE WATER, CHILE |
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ZHAO Xin1, CHEN Hong-Wei1, LI Wen-Peng1, LI Xin-Xin1,2,3
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1.Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China;2.Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen 518055, China;3.Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
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| Abstract: |
| Trench system is an important part of the global ocean. Studying the biogeochemical cycle in this extreme environment will help us understand the material recycling in the ocean. Previous studies have suggested that surface net primary production (NPP) contributed to the properties of organic carbon buried in trench sediments. However, the microbial community respiration (MCR) and the degradation of deposited particulate organic carbon (POC) through the extremely distant water column is unclear yet. To understand the temporal and spatial variations of MCR, POC, and their interactions, POC content, C/N, δ13C and δ15N of POC, along with the size fractionated MCR (0.2-0.8 μm, 0.8-3.0 μm, and >3.0 μm) of surface water (5 m) samples during cruise SO261, 2018 in the Atacama Trench, Chile, were analyzed. The results indicate that the 0.8-3.0 μm size fraction dominated the total MCR rates and potentially organic carbon degradation in this area. In addition, the MCR presented an M-shaped curve showing significantly greater numbers at night than daytime, which was consistent with the variation trends of C/N, δ13C, δ15N, suggesting that the MCR was mainly controlled by temperature over a day, and affected the elemental characteristics of POC. Spatially, the MCR in the trench stations were significantly greater than those in the non-trench stations and affected by NPP, with more complexed variation patterns. In the end, the respiratory degradation rate of NPP by microorganisms based on MCR was estimated 0.5%-4.6% in surface water of the Atacama Trench. |
| Key words: Atacama trench particulate organic carbon surface water respiration temporal and spatial distribution |
