Fluids are an important agent in almost all geologic processes that shape marine geology. Spatial and temporal variations in fluid flow activity modify total fluxes between geo-, cryo-, hydro-, and atmosphere. The natural release of fluids at the seafloor is called seepage, and the corresponding sites are called cold seeps when fluids are expelled at seawater temperature. Natural seepage is mainly associated with elevated greenhouse gases such as methane and carbon dioxide, which can alter the biogeochemical cycles at the seafloor. Cold seeps are characterized by high CH4 and shallow sulphate-methane transition zone in the sediment and lead lead to enhanced benthic anoxia and increased ocean acidification. Released greenhouse gases can directly escape into the water column, potentially reaching to the atmosphere. The release of fluids from subseafloor sediments also poses a major geohazard by decreasing the stability of slopes, fuelling mud volcanoes, or causing massive blowouts. At the same time, the release of methane and associated fluids may enhance primary production ( ‘oases of life’). Fluid flow linked to seepage can sustain highly diverse biological ecosystems or chemosynthetic communities on the seafloor. These habitats sustain active bacterial communities supporting anaerobic oxidation of methane (‘benthic filter’) and can buffer the released methane. However, especially in aquatic environments, a qualitative and quantitative understanding of methane cycling and fluxes across litho-, hydro- and atmospheres is contrained by the inaccessibility of offshore regions and associated difficulties in monitoring over spatial and temporal scales. This results in large uncertainties in quantifying and attributing emissions from offshore aquatic environments. Realistic estimates of aquatic methane emissions require a profound understanding of the involved fluid flow systems, including spatial and temporal variations, internal architecture, and preferential migration pathways through the overburden. Contributions may address natural fluid flow and seepage in marine or lacustrine environments across a large variety of settings. We welcome studies that integrate diverse geophysical, geochemical, biological, microbial, geological, remote sensing, numerical and laboratory approaches. Such interdisciplinary studies provide exciting opportunities to promote a better understanding of past and present fluid-driven systems in sedimentary systems.