Linking deep-sea biological communities (biotopes), ecological processes and ecosystem services: a systematic literature review

The Kunming–Montreal Global Biodiversity Framework (GBF) encourages the application of area-based management tools for the protection of biodiversity (so-called 30 by 30). The GBF sets out that biodiversity-ecosystem service assessments and information on location and the spatial extent of the ecosystem are needed to ensure understanding and effective management of biodiversity and natural resources. Habitat mapping is an essential element of this, and progress has been made in describing deep-sea benthic assemblages or biotopes for use as mapping units. What is lacking is a clear understanding of the link between mappable units (biotopes) and the ecosystem services (ES) they provide. This study develops a matrix to identify the ES provided by defined deep-sea biological assemblages (biotopes) to support conservation planning in the deep sea. Using a systematic literature review, we collate and summarise evidence of the links between 12 deep-sea biotopes in the Northeast Atlantic and their contribution to 15 ES. We find that cold-water coral reefs, Desmophyllum pertusum (formerly Lophelia pertusa) reefs, are a well-studied biotope, show contributions to regulating services, such as lifecycle maintenance and climate regulation, and provisioning services, such as food and biomedical benefits. Less or no knowledge exists for the other 11 biotopes. Knowledge gaps relate to their contribution to secondary production and regulating services, particularly how biotopes contribute to benthic–pelagic coupling, long-term climate regulation, cultural services and medical, genetic, and biochemical potential. This study underscores knowledge gaps and research priorities needed to effectively map services provided by these remote yet unique ecosystems.