Interaction between seafloor cold seeps and adjacent hydrothermal activities in the Okinawa Trough

As the seafloor extreme environmental systems, both hydrothermal vents and cold seeps are the critical pathways between the lithosphere and exosphere (biosphere, hydrosphere and atmosphere) for transfer and exchange of materials and energies. There are significant differences, but also many similarities between the two systems. Recent investigations show that in some special tectonic units, hydrothermal vents and cold seeps are not isolated from each other, but instead there are some interactions or coupling relationships in terms of tectonic geology, biological ecology and element cyclicity. As a typical back-arc basin in the western Pacific Ocean, there are abundant hydrothermal vents and cold seeps developed in the Okinawa Trough (OT). Therefore, it has become an ideal natural laboratory for studying the two extreme environmental systems and their interactions. On the basis of literature researches and careful field case studies, we investigate the material diffusion process and biogeochemical process between cold seeps and hydrothermal vents adjacent to each other within the trough. A conceptual model is then established for the interactions between the fluids from the two extreme systems. Our results suggest that it would help to establish a more complete model of the coupling relationship between the two systems in the future, if the structural development characteristics, pore fluid evolution, biological communities, and mineral chemistry of the two deep-sea extreme environments are systematically analyzed. Moreover, it will help to reveal the interaction between them in biological ecology and finally establish a model of interaction between hydrothermal vents and cold seeps on the basin scale, so as to better understand the interaction process between cold seeps and hydrothermal systems and even the coupling of " flow-solid” in the Western Pacific Ocean or the whole Earth.