| 摘要: |
| 根据2001年夏季长江口及东海西部海域表层海水pCO2的实测数据，结合水文、化学和生物等要素的同步观测资料，对该海域pCO2分布和变化的重要影响因素进行了探讨。结果表明，长江冲淡水是造成东海西部海域表层海水pCO2，分布不均匀的主要原因。利用Wanninkhof(1992)提出的通量模式计算，长江口口门附近海域和浙江近岸海域为CO2的源区，123°E以东的调查海域表现为大气CO2的汇，尤其是以123°E，32°N为中心，存在着一个极强的大气CO2汇区。就整个东海西部海域而言，夏季可从大气净吸收l5.3×104t C。 |
| 关键词: 东海, 二氧化碳分压(pCO2), 碳通量 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院知识创新工程重要方向项目，KZCX2-207号和国家“973”计划资助项目，2002CB412504号 |
附件 |
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| SUMMER SURFACE WATER pCO2 AND CO2 FLUX AT AIR-SEA INTERFACE IN WESTERN PART OF THE EAST CHINA SEA |
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TAN Yan1, ZHANG Long-Jun1, WANG Fan2, HU Dun-Xin2
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1.Ocean University of China，Key Laboratory for Marine Ecological and Environmental Science of Shandong Province;2.Institute of Oceanology，Chinese Academy of Sciences
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| Abstract: |
| In the study of the global carbon cycle, the continental margin is considered as one of probable sinks for missing term of carbon, and has come under increasing attention in recent years. It is of great importance, for the discussion of global carbon cycle and for the consummation of global carbon database, to study the CO2 flux over the East China Sea, a major marginal sea in the northwest Pacific.
This paper investigated CO2 flux over the East China Sea using the data collected during summer 2001(27 Jul一04 Aug). The procedures of sampling and analyses of surface water pCO2 were as followed: when the ship stayed still, pump surface water from a side intake at a depth of 3— 4m via an adiabatic conduit to equilibrator of laminary flow type(Cooper, 1998), which was presented by Plymouth Marine Laboratory. UK, turn on the air pump at the same time, and pump clean air that from 10m above the surface water to the laminary flow type equilibrator, in order to replace with water sample fully, then measure the samples of water and atmospheric pCO2 by G.C(Gas Chromatogram) simultaneously. The intake from which atmospheric air was pumped was installed at 10m above the water surface to avoid contamination from the ship. Temperature and salinity were measured synchronously by CTD(Conductivity Temperature Depth) system. Chlorophyll a was analyzed with the mensuration of Parsons(Parson, 1987). Nutrients were determined by SAN PLUS automatism (SKALAR company of Holand).
The results indicated that it was mainly the freshwater of Changjiang(Yangtzi) River that disturbed the pCO2 distribution in the surface water of survey area and made it uneven. Because of strong influence of fluvial carbonates, the pCO2 of surface water in the areas of Changjiang estuarine area and Hangzhou Bay were obviously higher than that of the rest area. There were positive correlation between the pCO2 of surface water and corresponding salinity, but negative correlation between the pCO2 of surface water and corresponding temperature, an d chlorophyll a except for the very muddy freshwater area near the Changjiang estuary. Using the gas exchange coefficient calculated from the Wanninkhof model (Wanninkhof, 1992) and the wind speed in situ, it is concluded that the Changjiang River estuarine area and offshore area near Zhejiang Province were source of CO2, while the area east to 123°E were sink of CO2, especially to the vicinity of 123°E 32°N, due to biological activities. The freshwater bring abundant nutrients which enhanced significantly biological activities, and thus largely increased consumption of CO2, which made the seawater (the area east to 123°E) to become the sink of atmospheric CO2. As far as the whole area of the western part of the East China Sea (the survey area is 14.4×104 km2) is concerned, 15.3×104t C was absorbed from atmosphere in summer. If the salinity of fresh water was considered to be less than 30, the area was 8. 03×104 km2, 19.0×104t C would be absorbed from atmosphere in summer by calculation. So it is mainly the freshwater of Changjiang River that resulted in the sink of CO2 in the western part of the East China Sea in summer. |
| Key words: The East China Sea, Partial pressure of CO2, Flux of CO2 |
