Large scale changes in the ocean are often driven by small scale processes mediated by interfaces between various compartments such as sediment/ocean, ocean/atmosphere (e.g., SOLAS science), cell/seawater and particle/seawater interfaces. However, the underlying processes and mechanisms occurring at the ocean interfaces are largely unknown and therefore their impact on large scale changes is difficult to predict. This session will bring together experimentalists and modelers from chemistry, biology, geochemistry and physical oceanography to discuss the latest developments of the investigation of the accumulation, transformation and transport of climate-relevant substances at and across the different ocean interfaces. We are looking for contributions dealing with all aspects of scientific and methodological/technical issues occurring at ocean interfaces spanning all temporal and spatial scales.