热带海洋学报 ›› 2024, Vol. 43 ›› Issue (4): 20-32.doi: 10.11978/2023117CSTR: 32234.14.2023117

• 综述 • 上一篇    下一篇

深海极端环境黑碳的地球化学特征及其环境意义*

李黛(), 王旭东(), 贾子策, 冯东   

  1. 上海海洋大学海洋科学与生态环境学院, 上海 201306
  • 收稿日期:2023-08-12 修回日期:2023-09-08 出版日期:2024-07-10 发布日期:2024-07-22
  • 作者简介:

    李黛(1998—), 女, 广东省潮州市人, 硕士研究生, 从事海洋沉积地球化学研究。email:

    *感谢编辑部老师和三位匿名审稿专家提出的宝贵建议

  • 基金资助:
    国家自然科学基金(42106059); 上海市青年科技英才扬帆计划(21YF1416800); 上海市教育发展基金会和上海市教育委员会“晨光计划”项目(22CGA58)

Geochemistry of black carbon in marine extreme environments and its environmental implications*

LI Dai(), WANG Xudong(), JIA Zice, FENG Dong   

  1. College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China
  • Received:2023-08-12 Revised:2023-09-08 Online:2024-07-10 Published:2024-07-22
  • Supported by:
    National Natural Science Foundation of China(42106059); Shanghai Sailing Program(21YF1416800); Shanghai Chenguang Program(22CGA58)

摘要:

黑碳是一种广泛存在于不同环境中且抗氧化、耐分解的含碳物质。作为惰性有机碳的重要组分, 黑碳深刻影响着全球碳循环。当前海洋黑碳收支的不平衡研究结果表明海洋中可能存在未知的或被忽略的黑碳来源或埋藏路径。随着深渊海沟、热液区和冷泉区等这些地球上最为极端的海洋环境黑碳研究的不断深入, 已经确认这些环境中存在独特的黑碳循环过程, 可能是海洋黑碳的重要源或汇。本文综述了海洋极端环境中黑碳的地球化学特征, 发现深渊海沟独特的“V”字型地形有利于物质汇聚, 其中的黑碳比同沉积的有机碳更为古老, 黑碳年埋藏量可达约(1.0±0.5)Tg; 热液区的高温流体通过“灼烧”有机质形成原位自生黑碳, 其每年向海洋贡献的黑碳可达1.6~9.7Tg, 是海洋黑碳的重要来源; 冷泉区黑碳的源汇过程尚不清楚, 但区域内丰度极高的甲烷厌氧氧化古菌最近被证明可以直接产生黑碳, 其碳同位素值负偏至-60‰以下, 这是迄今为止唯一的一种微生物来源黑碳, 是对黑碳类型传统认识的重要补充。尽管目前已经建立海洋黑碳源汇过程的总体框架, 但尚缺乏对海洋极端环境黑碳的直接形态观察及特征分析, 未来的研究需要明确海洋极端环境中陆源黑碳与海洋自生黑碳的比例, 以进一步了解海洋黑碳源汇过程并探讨极端环境黑碳在海洋碳循环中扮演的角色。

关键词: 黑碳, 深海极端环境, 地球化学特征, 源汇过程

Abstract:

Black carbon is one of the carbonaceous materials, it exists ubiquitously in the environment and could be resistant to oxidation and decomposition. Black carbon might strongly affect the global carbon cycle as an important component of recalcitrant organic carbon. The current discrepancy of marine black carbon budgets indicates that there are unknown sources or buried pathways of black carbon in the ocean. It has been confirmed that marine extreme environments, such as abyssal trenches, hydrothermal vents and cold seeps, may be important sources or sinks of marine black carbon with the continuous deepening of the research on black carbon in these environments. In this review, the geochemical characteristics of black carbon in extreme marine environment are summarized. It is found that the unique “V”-shaped terrain of the abyssal trenches is conducive to the accumulation of materials, in which the black carbon is older than the syn-sedimentary organic carbon, and the annual buried amount of black carbon is about (1.0±0.5) Tg. The high-temperature fluid in hydrothermal vents forms in-situ authigenic black carbon by “burning” organic matter, and its annual contribution to the ocean is about 1.6~9.7Tg, which is an important source of marine black carbon. The source and sink process of black carbon in cold seeps remain unclear, but the high abundance of anaerobic methanotrophic archaea in these areas has recently been proved to directly produce black carbon, and its carbon isotope value is negatively below -60‰. As the only microbial source of black carbon found so far, it is an important supplement to the traditional understanding of black carbon types. The overall framework of marine black carbon source and sink process has been established notwithstanding, there is a lack of direct morphological observation and characterization of black carbon in marine extreme environments. It is necessary to clarify the ratio between terrestrial black carbon input and marine authigenic black carbon in extreme marine environments, to further understand the source and sink process of marine black carbon and explore the role of extreme environmental black carbon in marine black carbon budgets in the future.

Key words: black carbon, marine extreme environments, geochemical characteristics, source-sink processes