MASTS Policy Brief: Protecting Scotland's Deep Sea in a Changing Climate

Deep-sea environments, in contrast to coastal ecosystems, are generally less adaptive to environmental changes and its species and habitats are therefore more sensitive to climate change impacts. The ocean has absorbed most of the additiona lheat and about a quarter of the additional atmospheric carbon dioxide from human activities. Even though this has helped keep the planet cooler than it would otherwise be, this has also caused deep-sea ecosystems to increase in temperature and acidity, lose oxygen, and have less food available. These changes to deep-sea ecosystems will: reduce the capacity of deep-sea sediments to store carbon and recycle nutrients; impact coral reef structure and complexity, reducing associated biodiversity and functions; impact deep-sea sponges risking, for example, a loss of natural pharmaceuticals; and impact fishing activities. By taking decisive action to address climate change, strengthen existing protections, and fill critical knowledge gaps, Scotland can ensure the long-term health and resilience of its unique and valuable deep-sea ecosystems The following actions are recommended: 1. Assess the resilience of the existing Marine Protected Area (MPA) network to climate change. Identify climate change refugia and predict shifts in ecological connectivity, informing adaptive management strategies and the development of strategic approaches to ensure MPAs effectively protect deep-sea features under current and future conditions. 2. Reduce existing human pressures to support resilience and recovery. This will increase the opportunities for resilience of species and habitats to the impacts of climate change, improving their ability to adapt and survive. This protects the many benefits that Scottish people receive from the deep sea. 3. Address knowledge gaps. Impacts of climate-induced environmental change at species, habitat and ecosystem level, that are in addition to the impacts of fishing and pollutants, require continued investigation. This should include pelagic ecosystems, vulnerable and important species (e.g. sponges, corals, fish), deep-sea sediments and the carbon sink. 4. Strongly advocate for global reductions in greenhouse gas emissions.