引用本文: | 张岩松,章飞军,郭学武,张曼平.东海秋季典型站位沉降颗粒物通量.海洋与湖沼,2006,37(1):28-34. |
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东海秋季典型站位沉降颗粒物通量 |
张岩松1,2, 章飞军3,4, 郭学武3, 张曼平5
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1.中国水产科学研究院黄海水产研究所 农业部海洋渔业资源可持续利用重点开放实验室;2.胶州市环境保护局 胶州;3.中国水产科学研究院黄海水产研究所农业部海洋渔业资源可持续利用重点开放实验室;4.华东师范大学河口海岸国家重点实验室 上海;5.中国海洋大学化学化工学院 青岛
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摘要: |
2002年9月在东海的长江口、中陆架区和浙江近岸上升流区三个站位放置沉积物捕获器采集沉降颗粒物。在对颗粒有机碳(POC)、颗粒有机氮(PON)和总颗粒碳(PC)元素分析基础上,采用颗粒物通量模型对沉降通量进行了研究。镜检发现细小无机颗粒物和大颗粒聚合体是三个站位沉降颗粒物的主要形式。大颗粒聚合体有住囊类、粪球聚合体、硅藻聚合体和混杂聚合体四种类型。研究结果显示,东海中陆架区和浙江近岸上升流区沉降颗粒物中POC、PON和PC的百分含量均呈现随水深增加明显降低的趋势,但在长江口,这些成分的含量低且上下均匀。长江口观测到的是大风后的一个实例,存在强烈的再悬浮,各水层颗粒物沉降通量平均(±SE)高达(319.02±65.33)g/(m2.d),尽管如此,沉降颗粒物有机态C/N值却很高(18.0±0.9),明显受陆源颗粒物的影响。POC净沉降通量在浙江近岸上升流区为961mg/(m2.d)(水深55m),在东海中陆架区为123mg/(m2.d)(水深88m),可见浙江近岸上升流区是POC向海底转移的重要区域之一,其垂直转移能力明显高于东海中陆架区。在上升流区域和中陆架区,POC的输出比率大约分别为48%-77%和15%-21%。浙江近岸上升流区和东海中陆架区底层颗粒物再悬浮比率分别为66.50% 和88.52%。研究显示, 浙江近岸上升流区的水体底层颗粒物受底部平流的影响比东海中陆架区相对较强。 |
关键词: 沉降颗粒物, 聚合体, 颗粒有机物, 沉降通量, 再悬浮比率, 东海 |
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基金项目:国家重点基础研究发展规划项目,G19990437号 |
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AUTUMN FLUX OF PARTICLE SETTLING OBSERVED AT THREE REPRESENTATIVE STATIONS IN EAST CHINA SEA |
ZHANG Yan-Song,ZHANG Fei-Jun,GUO Xue-Wu,ZHANG Man-Ping
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1.Key Laboratory for Sustainable Utilization of Marine Fisheries Resource, Ministry of Agriculture, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao;2.Jiaozhou Environmental Protection Bureau, Jiaozhou;3.State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai;4.College of Chemistry and Chemical Engineering, Ocean University of China
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Abstract: |
Settling particle was collected using Bloesch multi-tube sediment traps in the East China Sea in September 2002. The traps were surface-tethered at three representative stations located in Changjiang (Yangtze) River estuary, coastal upwelling zone off Zhejiang, and middle continental shelf. The types of particles, contents of particulate organic carbon (POC), organic nitrogen (PON) and total carbon (PC), and ratio of carbon to nitrogen (C/N ratio) in organic matter, were analyzed. The fluxes of settling particulate matter, POC, PON, and PC, as well as the resuspension ratio in bottom layer were estimated based on flux models assuming that the flux in lower layer of a thermocline equals to the net flux of a whole water column. Microscopical examination showed that inorganic fine particles and biogenic particle aggregates were grouped into two main types of settling particulate matter at the three stations. The particle aggregates contained larvacean houses, fecal aggregates, diatom aggregates and miscellaneous aggregates, same as that collected generally in deep sea. The contents o f POC, PON, and PC declined significantly with the increase of water depth at the stations in both the upwelling zone and the middle continental shelf, but all were low and approximate between layers at the station in Changjiang estuary, where particle flux was very high, 319. 02g/(m2.d) in average among three layers, because of the wind driven resuspension of sediments, but the C/N ratio still kept at a high level, about 18.0 in average, indicating their land sourced feature. The net fluxes of POC at stations in the upwelling zone and the middle continental shelf were assessed at 961mg/(m2.d) and 123mg/(m2.d), respectively. It means that the upwelling zone off Zhejiang would be inevitably an important ground for sinking of POC. The POC export ratios were assessed at about 48%–77% and 15%–21% in the upwelling zone and the middle continental shelf respectively. Higher export ratio o f POC in the upwelling zone was probably connected to the high production sustained by the upwelling itself. The resuspension ratios in the bottom layer averaged 66.50% and 88.52% at the stations in the upwelling zone and the middle continental shelf, respectively. No significantly different (t-test, P = 0.397) was shown between the two models proving again that a net flux could be replaced by the flux in lower layer of a thermocline in stratification cases. The contribution of particulate matter driven by lateral current to the total resuspension flux was also estimated based on the portion of total resuspension flux constituted by particles resuspended from sediments nearby sampling station. The portions were valued 24. 38% and 94.72% at stations in the upwelling zone and the middle continental shelf respectively. It implies that the influence of lateral current to the total resuspension flux is relatively more intensive in the upwelling zone than that in middle continental shelf. |
Key words: Settling particulate matter, Aggregates, Particulate organic matter, Particle flux, Resuspension ratio, The East China Sea |
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