Global marine methane seepage: Spatiotemporal patterns and ocean current control

IF 2.6 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Marine Geology Pub Date : 2025-05-25 DOI:10.1016/j.margeo.2025.107589

Xin Ni , Xiuguo Liu , Shilong Pang , Yifei Dong , Binbin Guo , Yuhang Zhang , Yang Wu , Danyi Su , Andi Xu , Qinmeng Yuan , Xuemin Wu , Lin Yang , Xiaoyu Wu , Zhigang Wang , Xi Xiao , Qianyong Liang

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引用次数: 0

Abstract

Marine sediments contain substantial methane reservoirs that play a significant role in global carbon cycling and climate systems. However, methane seepage is significantly influenced by ocean dynamics, with poorly understood spatiotemporal patterns. To investigate the spatiotemporal distribution patterns of methane seepage and the regulatory mechanisms of ocean currents, comprehensive coordinates and flux data of methane seepage from multiple marine regions worldwide were compiled. The spatial characteristics of methane seepage were quantified using nearest neighbor analysis and kernel density estimation, whereas the local and global autocorrelation between seepage activities, ocean currents, and sea surface temperatures were evaluated using Moran's index. Two clustering algorithms, spatiotemporal density-based spatial clustering of applications with noise (ST-DBSCAN) and ordering points to identify the clustering structure (OPTICS), were employed to identify the synergistic effects between temperature gradients and ocean current convergence zones through multiscale and hierarchical clustering approaches. Deep ocean currents may regulate methane seepage through multiple pathways: affecting hydrate stability via temperature gradients, altering local pressure fields through water level and flow velocity fluctuations, and influencing microbial geochemical processes through water mass exchange. The results indicate that methane seepage is most active in the circum-Pacific region and continental shelf areas, with approximately 42 % of seepage hotspots occurring in warm–cold current convergence zones. Mesoscale identification at 500 km reveals the influence of hydrodynamic processes such as eddies and fronts, whereas accessibility analysis quantitatively characterizes the hierarchical spatial associations of methane seepage, indicating enhanced seepage activity in warm current regions. These findings demonstrate the multiple control mechanisms of ocean currents on seafloor methane release through coupled temperature, pressure, and geochemical effects. This research provides a scientific foundation and a technical reference for quantitatively assessing the potential contribution of marine methane to global carbon cycling and identifying areas susceptible to elevated seepage.

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全球海洋甲烷渗漏：时空格局与洋流控制

海洋沉积物含有大量的甲烷储层，在全球碳循环和气候系统中起着重要作用。然而，甲烷渗流受海洋动力学的显著影响，但对其时空格局知之甚少。为探讨甲烷渗流时空分布格局和洋流调控机制，编制了全球多个海洋区域甲烷渗流综合坐标和通量数据。利用最近邻分析和核密度估计量化了甲烷渗流的空间特征，并利用Moran指数评价了渗流活动与海流和海面温度之间的局部和全局自相关关系。采用基于时空密度的带噪声应用空间聚类（ST-DBSCAN）和有序点识别聚类结构（OPTICS）两种聚类算法，通过多尺度和分层聚类方法识别温度梯度与海流辐合带之间的协同效应。深海洋流可能通过多种途径调节甲烷渗流：通过温度梯度影响水合物稳定性，通过水位和流速波动改变局部压力场，通过水体质量交换影响微生物地球化学过程。结果表明：环太平洋地区和大陆架地区甲烷渗流最为活跃，约42%的渗流热点发生在暖流寒流辐合带；500 km的中尺度识别揭示了涡旋和锋面等水动力过程的影响，而可达性分析定量表征了甲烷渗流的分层空间关联，表明暖流区域的渗流活动增强。这些发现表明，洋流通过温度、压力和地球化学效应对海底甲烷释放的多重控制机制。本研究为定量评估海洋甲烷对全球碳循环的潜在贡献和识别海洋甲烷渗漏增加的敏感区提供了科学依据和技术参考。

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来源期刊

Marine Geology 地学-地球科学综合

CiteScore

6.10

自引率

6.90%

发文量

175

审稿时长

21.9 weeks

期刊介绍： Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.