The active cold seep at Formosa Ridge (Site F) sustains the most flourishing ecosystem on the continental slope of the northern South China Sea. However, the physicochemical environment around the cold seep has scarcely been investigated. The knowledge about the variability of the seafloor habitat around the cold seep was poor and the key processes within the associated chemosynthetic ecosystem remain unclear. Here, we used an in situ integrated sensors detection approach combined with geochemical measurements to investigate the environmental condition around the chemosynthetic ecosystems fueled by the hydrocarbon seepage. Methane, hydrogen sulfide, dissolved oxygen and other biogenic elements in the bottom water were detected on a fine scale. The mixed gas composition and carbon isotope value of methane from the vent fluids suggested its origin was predominantly biogenic with slight thermogenic incorporation. Both horizontal and vertical variations in methane and oxygen concentrations were observed, which showed contrasting trends in fields from the center of flourishing communities to the margin of sediments. The concentration of methane decreased from 31,200 ppm at the flourishing center to 381 ppm at the margin on a horizontal gradient. The low concentration of hydrogen sulfide indicated that sulfide could be an energy-limiting factor for chemoautotrophic symbionts. The in situ oxygen levels were variable near the flourishing community but homogeneous at the margins. The results suggested that the availability of oxygen and methane played a substantial role in structuring the seep communities. Overall, from the flourishing center to the periphery, the chemical gradients drive the spatial distribution of chemosynthetic community at site F. The observations of the fine scale survey highlight the heterogeneity of microenvironments and provide novel information on the environmental dynamics within site F for the first time.

福尔摩沙岭（F地带）活跃的冷渗漏区维持着南海北部大陆坡上最繁茂的生态系统。但是，很少研究冷渗漏周围的物理化学环境。关于冷渗漏周围海底生境的可变性的知识很贫乏，并且相关化学合成生态系统内的关键过程仍然不清楚。在这里，我们使用了原位集成的传感器检测方法与地球化学测量相结合，以研究由碳氢化合物渗入推动的化学合成生态系统周围的环境条件。精细检测了底部水中的甲烷，硫化氢，溶解氧和其他生物元素。排放气中甲烷的混合气体组成和碳同位素值表明，甲烷的来源主要是生物成因，并伴有少量热成因。甲烷和氧气浓度的水平和垂直变化都可以观察到，这表明从蓬勃发展的群落中心到沉积物边缘的田间形成了相反的趋势。甲烷的浓度从繁荣中心的31,200 ppm下降到水平梯度边缘的381 ppm。低浓度的硫化氢表明硫化物可能是化学自养共生体的能量限制因素。这在繁荣的社区附近，原地的氧气水平是可变的，但在边缘处是均匀的。结果表明，氧气和甲烷的可利用性在构造渗流群落方面发挥了重要作用。总体而言，从繁华的中心到外围，化学梯度驱动站点F的化学合成群落的空间分布。精细规模调查的观察结果突出了微环境的异质性，并首次为站点F内的环境动力学提供了新颖的信息。时间。