| 摘要: |
| 黄东海接受长江冲淡水和黑潮带来的大量营养盐和有机物质，其碳循环对陆架海碳源汇格局至关重要。浮游生物群落呼吸是影响碳循环的重要过程。为揭示黄东海浮游生物群落呼吸率（PCR）对碳平衡的贡献，于2011年四季使用黑白瓶培养法测定黄海南部及东海北部浮游群落呼吸率和初级生产力，并同步测定温度、盐度、营养盐、叶绿素和细菌丰度等环境因子。结果显示，浮游生物群落呼吸率的变化范围为1.61~834.84 mg C/（m3·d），年均为（184.53±154.21） mg C/（m3·d），其中夏季最高，冬季最低。根据相关性分析，黄东海研究区域浮游生物群落呼吸率，尤其是在夏天，主要由浮游植物和浮游细菌贡献；浮游生物群落呼吸率与温度呈显著正相关，与盐度和硅酸盐呈显著负相关。通过比较群落呼吸率与初级生产力，得到研究海区水柱总体呈现异养状态；部分站位表层或10 m水层呈现出自养状态。海气CO2交换通量的研究显示，黄东海陆架主要表现为大气CO2的碳汇区域。研究提出，黄东海陆架碳平衡总体异养、却为碳汇的主要原因可能为：研究区域表层初级生产吸收CO2高于呼吸产生CO2，常表现为自养和碳汇；但表层沉积物的再悬浮和外源有机碳输入为次表层以下水体提供了丰富的有机碳，浮游生物群落呼吸产生的CO2高于初级生产吸收的CO2，呈现异养。当台风等物理外力破坏水层结构使水体混合时，次表层及以下的CO2将释放到大气中，表现为碳源。 |
| 关键词: 浮游生物群落呼吸率 陆架海 碳平衡 黄东海 |
| DOI：10.11693/hyhz20210600139 |
| 分类号:P735;Q938;Q179.1;O613.71 |
| 基金项目:国家重点研发计划资助，2018YFD0900901号；长江口－浙江近海－邻近东海多学科长期观测计划，14282号；国家重点基础研究发展计划，2010CB428903号；国家海洋局青年科学基金，2013140号；自然资源部海洋生态监测与修复技术重点实验室开放基金资助项目，MEMRT202106号；“全球变化与海气相互作用”专项（II期）—长江口缺氧酸化预警监测。 |
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| THE IMPORTANCE OF PLANKTON COMMUNITY RESPIRATION RATE TO CARBON FLUX BALANCE IN THE YELLOW AND EAST CHINA SEA |
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YE Wen-Qi, LIU Cheng-Gang, CAI Yu-Ming, ZHAI Hong-Chang, LE Feng-Feng, WANG Bin, SHOU Lu, CHEN Quan-Zhen, DU Ping
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Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Hangzhou 310012, China
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| Abstract: |
| The Yellow Sea and East China Sea receive a large amount of nutrients and organic materials from the Changjiang (Yangtze) River dilution water and the Kuroshio, in which carbon cycle is very important to the carbon source and sink pattern of the continental shelf sea. Plankton community respiration is an important process that affects carbon cycle. To reveal the contribution of plankton community respiration rate (PCR) to the carbon balance in the Yellow Sea and the East China Sea, we used the black-and-white-bottle culture method to measure the plankton community respiration rate and primary productivity in the southern Yellow Sea and the northern East China Sea during the four seasons of 2011, and simultaneously measured the environmental factors such as temperature, salinity, nutrients, chlorophyll a and bacterial abundance. The results show that the plankton community respiration rate varied from 1.61 to 834.84 mg C/(m3·d), on annual average of (184.53±154.21) mg C/(m3·d), and the highest value occurred in the summer, while the lowest in the winter. According to the correlation analysis, the plankton community respiration rate, especially in summer, is mainly contributed from phytoplankton and bacterioplankton, and the plankton community respiration rate is significantly positively correlated with temperature, but significantly negatively correlated with salinity and silicate. Comparison between plankton community respiration rate and primary productivity shows that the studied area was heterotrophic but autotrophic in some surface layers. Studies on the exchange flux of sea-air CO2 present that continental shelf regions of the Yellow Sea and East China Sea are mainly sinks of atmospheric CO2. However, why the Yellow and East China Sea ecosystems are heterotrophic in overall on one hand, and are sinks of atmospheric CO2 on the other? The main reasons may be as follows: (1) the in-situ primary productivity in the studied area is low, and the organic carbon sources mainly depend on exogenous organic carbon or the re-suspension of surface sediments; (2) the CO2 produced by the respiration of the plankton community is fixed in the subsurface water in the form of dissolved inorganic carbon. When an external force destroyed the structure of the water layer and forced the local water mixed, the fixed CO2 could be released into the atmosphere, and become a carbon source of atmospheric CO2 consequently. |
| Key words: plankton community respiration (PCR) continental shelf sea carbon flux balance the Yellow and East China Sea |
