| 摘要: |
| 基于2022年11月（秋季）和2023年2月（冬季）在深圳杨梅坑海域的调查结果并结合室内培养实验所获得的数据，探究了枯水季节典型亚热带珊瑚礁海水二氧化碳分压（pCO2）的分布特征及主要控制机制。结果表明，调查期间pCO2的变化较大，其范围为233.3~465.3 μatm。秋季表现为大气二氧化碳（CO2）的汇，CO2吸收通量为1.66±0.41 mmol C/m2/天；冬季表现为大气CO2的弱源，其释放通量为0.36 ±0.17mmol C /m2/天。调查期间（枯水季）杨梅坑海域受淡水输入的影响较小，季节性温度影响下的生物过程是驱动pCO2变化的关键因素，其贡献pCO2总变化量的73.6%（表层）和66.5%（底层）。其中，浮游植物光合作用的季节差异是导致海水CO2汇源转变的主要成因，而微生物呼吸作用的影响甚微。相比较，物理过程（CO2海-气交换、温度和盐度变化）对pCO2的影响相对较小，其作用结果远低于生物过程。此外，珊瑚的代谢活动对杨梅坑局部海域pCO2分布产生一定影响，造成礁区pCO2值高于非礁区。因此，海气CO2通量估算中不能忽视局部海域珊瑚代谢作用的影响。 |
| 关键词: 珊瑚礁 CO2分压 海气CO2通量 源汇特征 杨梅坑海域 |
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| 基金项目:深圳市可持续发展专项(KCXFZ20211020165547011)；中国博士后科学(2022M721792)；广东省基础与应用基础研究(2023A1515012204)；广东省基础与应用基础研究(2022A1515110345)Funding: Sustainable Development Project of Shenzhen (KCXFZ20211020165547011); General Project of China Postdoctoral Fund (2022M721792); Guangdong Basic and Applied Basic Research Foundation (2023A1515012204); Guangdong Basic and Applied Basic Research Foundation (2022A1515110345) |
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| The distribution characteristics of pCO2 and the source-sink conversion mechanism of CO2 in a subtropical coral reef water during dry season : A case study of Yangmeikeng sea area in Shenzhen, China |
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Zhang Zhuo1, Yang Bo2, Cui Zhouping2, Lin Ziyi2, Xie Ziqiang2, Zheng Huina2, Liao Baolin2, Xiao Baohua2, Zhu Chunhua1
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1.College of Fisheries,Guangdong Ocean University,Zhanjiang;2.Shenzhen Institute of Guangdong Ocean University,Shenzhen
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| Abstract: |
| Based on the field surveys conducted in the Yangmeikeng sea area of Shenzhen in November 2022 (autumn) and February 2023 (winter), along with data obtained from indoor culture experiments, this study aimed to explore the distribution characteristics of seawater partial pressure of carbon dioxide (pCO2) and its main control mechanisms in a typical subtropical coral reef during the dry season. The investigation revealed significant variation in pCO2, ranging from 233.3 to 465.3 μatm. During autumn, the study area acted as a sink for atmospheric CO2, with an absorption flux of 1.66 ± 0.41 mmol C/m2/day. Conversely, during winter, it exhibited a weak source of atmospheric CO2, with an emission flux of 0.65 ± 0.14 mmol C/m2/day. Notably, the Yangmeikeng sea area experienced minimal influence from freshwater input. The biological process under the influence of seasonal temperature was the key factor driving the seasonal variation of pCO2, contributing 73.6 % (surface) and 66.5 % (bottom) of the total variation. Among them, the seasonal difference of phytoplankton photosynthesis was the main cause of the transformation of seawater CO2 from sink to source, while the effect of microbial respiration was weak. In comparison, physical processes, i.e., sea-air exchange of CO2 and the changes of temperature and salinity, have a weak effect on the pCO2 dynamic, which was much lower than that of biological processes. Furthermore, the metabolic activity of corals had a noteworthy impact on pCO2 distribution in the local sea area of Yangmeikeng, resulting in a higher pCO2 value in the reef area than that in the non-reef area. Thus, the influence of coral metabolism in local sea area cannot be ignored in the estimation of air-sea CO2 flux. |
| Key words: Coral reefs CO2 partial pressure Air-sea CO2 flux Source-sink characteristics Yangmeikeng sea area |