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| 南海三沙永乐龙洞悬浮体组分及其来源 |
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孙晓霞1, 傅亮2, 杨作升1,2, 毕乃双1, 范德江1, 姚鹏3, 刘光兴4, 陈洪举4, 田元1, 刘瑞志5
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1.中国海洋大学海底科学与探测技术教育部重点实验室 青岛 266100;2.中国航迹三沙珊瑚礁保护研究所 三沙 573199;3.中国海洋大学海洋化学理论与工程技术教育部重点实验室 青岛 266100;4.中国海洋大学海洋环境与生态教育部重点实验室 青岛 266100;5.中国环境科学研究院河口与海岸环境国家重点实验室 北京 100018
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| 摘要: |
| 三沙永乐龙洞位于南海北部永乐环礁上，水深达300m，是世界已知最深的海洋蓝洞。采用扫描电镜和能谱仪对2016年10月和2017年3月在永乐龙洞从表层到270m的24个不同深度采集的水体悬浮体组分进行了分析，发现悬浮体组分种类丰富，粒度差异大，来源/成因多样，可分为生源碎屑、陆源碎屑、自生矿物颗粒、有机包膜-海洋雪花和人工产物碎屑等5类。生源碎屑以碳酸盐为主，主要来自现代珊瑚礁的松散沉积物，是悬浮体的主要组分。陆源碎屑主要是造岩矿物如石英和长石，以及一些包括重矿物的副矿物，其中细小的陆源造岩矿物碎屑，有可能来自气溶胶沉降，粗粒碎屑可能来自附近琛航岛工程散落的海南岛沿岸海砂。自生矿物颗粒包括重晶石、球状微粒氧化铁集合体和纳米黄铁矿。纳米黄铁矿及其集合体出现在130m以深水体中，是含硫化氢的无氧极端水体的特定产物。有机包膜在生物降解过程中形成，有时包覆多个不同组分的颗粒，常呈片状漂浮在水体中，形成海洋雪花。人工产物碎屑包括多种金属碎屑、微塑料纤维丝和过硫化铅丝。金属碎屑可能来自船只金属部件耗损，微塑料纤维可能来自渔网残余。本文是首次有关海洋蓝洞悬浮体组分的系统报道。永乐龙洞悬浮体组分特色鲜明，对认识其生态系统和沉积记录有重要意义。 |
| 关键词: 三沙永乐龙洞 悬浮体组分 物源 珊瑚礁碳酸盐 陆源碎屑 极端水环境 |
| DOI：10.11693/hyhz20171200332 |
| 分类号:P736.21 |
| 基金项目:三沙航迹珊瑚礁保护研究所航迹南海海洋科研发展项目，HJLD16-01，HJLD17-01号；中央高校基本科研业务费项目，201762038号。 |
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| COMPONENTS AND ORIGIN OF SUSPENDED MATTER IN THE SANSHA YONGLE BLUE HOLE, SOUTH CHINA SEA |
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Sun Xiao-Xia1, Fu Liang2, Yang Zuo-Sheng1,2, Bi Nai-Shuang1, Fan De-Jiang1, Yao Peng3, Liu Guang-Xing4, Chen Hong-Ju4, Tian Yuan1, Liu Rui-Zhi5
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1.Key Laboratory of Submarine Geosciences and Prospecting Technique, Ocean University of China, Ministry of Education, Qingdao 266100, China;2.Sansha Trackline Institute of Coral Reef Environment Protection, Sansha 573199, China;3.Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education, Qingdao 266100, China;4.Key Laboratory of Ministry of Education for Marine Environment and Ecology, Ocean University of China, Qingdao 266100, China;5.Chinese Research Academy of Environmental Sciences, State Environmental Protection Key Laboratory of Estuarine and Coastal Environmen, Beijing 100018, China
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| Abstract: |
| The Sansha Yongle blue hole is located in the Yongle coral atoll in the northern South China Sea. Being deeper than 300 m, the Yongle blue hole is the deepest marine blue hole in the world. Water samples at 24 different depths from surface to 270m in the blue hole were collected in October 2016 and March 2017. The particle components of suspended matter of the water samples were studied in SEM (scanning electron microscope) and X-ray energy dispersive analysis. The grain sizes, mineral components, and their sources/origins varied greatly. The mineral components could be classified into five groups:the biogenous debris, terrestrial debris, authigenic particles, organic films-marine snowflakes, and debris of modern artificial materials. The biogenous debris, composed mainly of carbonate particles, is originated from loose sediments on the coral reef flat and is the dominant component of the suspended matter. The terrestrial debris consists of rock-forming minerals such as quartz and feldspars, and are associated with some heavy minerals. The fine part of the terrestrial rock-forming debris may originate from aerosols deposition. The coarse part may come from the beach sands of the Hainan Island used for construction activities in Chenhang Island nearby. The authigenic components consist of barite, the spherical aggregate of micro-grains of iron hydroxide, and nano-pyrite. The nano-pyrites and their spherical aggregates were found in waters below 130m as a specific component formed in the anoxic waters with sulfide hydrogen. Organic films are formed through the decay of organism relict in the water column and frequently cover or pack suspended grains. In low density, the films are often floating in water as marine snowflakes. The components of artificial product consist of different metallic debris, microplastic fibers, and lead sulfide wires. The metallic debris may come from the abrasion of the metallic parts of boats or ships. The microplastic fibers may come from the relict of fishing nets. This paper is the first report of a systematic research on particle components of suspended matter in the marine blue hole. Our results show that the suspended matter components in the Yongle blue hole are quite distinctive. This study would be helpful for the understanding of the unique ecology system and sedimentation history in the blue hole. |
| Key words: Sansha Yongle blue hole suspended matter component material source coral reef carbonates terrestrial debris extreme water environment |