\ua9 2025 The Author(s)Oxygen is vital for marine life. Despite global ocean deoxygenation, coastal oxygen dynamics are poorly understood. We synthesise the biological and mechanical processes that shape the coastal oxyscape and how organisms respond to it. Oxygen availability can determine species ecophysiology and affect population dynamics and ecological interactions. We propose a novel conceptual framework to reassess oxygen as a resource that is both density-independent and density-dependent, and identify spatial and temporal patterns of competition in coastal ecosystems. Our framework aims to (i) advance eco-evolutionary theory, (ii) improve species distribution models, (iii) inform effective conservation strategies, and (iv) enhance insight into coastal ecosystem-level responses to oxygen fluctuations, thereby advancing our understanding of environmental complexity under climate change, which in turn can guide management
