The Arctic Ocean is particularly exposed to environmental changes such as warming and desalinization caused by melting continental ice. These changes will have major effects on Arctic organisms and communities. The ORCA project focuses on studying the effects of environmental conditions on Arctic benthic ecosystems. This project has three components. An experimental component that will use perturbation experiments to study the effects of multiple factors on the physiology of benthic organisms. An in situ experimental component to determine the metabolism of benthic communities exposed to a wide range of environmental conditions. A dissemination component to explain to a broad audience the major problems that the Arctic is facing. ORCA will highlight the major changes occurring in the Arctic and their consequences for benthic organisms.