• Kinorhyncha community of the Aleutian Trench consist of 10 species. • A new Kinorhyncha species, Cristaphyes unangax sp. nov., is described. • The axis has high abundance may be due to organic matter accumulation. • The high abundance at a slope site (abyssal), may result from upwelling or terraces. • Meiofauna can disperse across the Aleutian and Kuril-Kamchatka trenches. Several species of trench-dwelling meiofaunal animals, including Kinorhyncha, have been described in recent years; however, our knowledge on kinorhynchs inhabiting abyssal and even hadal depths is still extremely scarce. In the present study, we explore the Kinorhyncha community of the Aleutian Trench, North Pacific Ocean, an under-sampled region in terms of meiofauna. As a result, a new species of Cristaphyes inhabiting abyssal and hadal depths of the trench is described. Cristaphyes unangax sp. nov. is characterized by the presence of middorsal processes on segments 1 – 10, with the last one extending well-beyond the posterior margin of the trunk. Cristaphyes unangax sp. nov. thus becomes the fourth hadal species described within the phylum Kinorhyncha. In terms of biodiversity, abundance of adult kinorhynchs remains relatively low along the trench’s depth gradient (c.a. 3.500 – 7.200 m), except at two sites: one at the axis and another at the slope. The higher abundance at the axis aligns with patterns in other trenches, where organic matter accumulation enhances microbial activity, supporting meiofaunal communities. The elevated specimens at the slope station, located at abyssal depth, may result from Aleutian upwelling currents or trench terraces that facilitate food deposition. The Kinorhyncha community in the Aleutian Trench is dominated by Echinoderes ultraabyssalis and includes another nine species, many shared with the North Pacific and Arctic. These findings suggest that meiofauna in the North Pacific can disperse across bathymetric barriers, potentially linking the Aleutian and Kuril-Kamchatka trenches. Additionally, the Aleutian Trench may serve as a migration corridor for meiofauna between the North Pacific and Arctic, aided by strong bottom currents. Zoobank : urn:lsid:zoobank.org:pub:56D1BA0B-3D9F-4547-84BC-C9BAFCA1D220

19 pages, 13 figures, supplementary data https://doi.org/10.1016/j.pocean.2025.103494.-- Data availability: All data used in this study are freely available in public repositories described in the paper

• We propose a Global Coastal Ocean Climate Model Intercomparison Project (GCO-MIP). • We explore the modelling challenges of coastal ocean climate downscaling. • Motivated by societal drivers e.g. ecosystems, coastal hazards and marine economy. • Downscaling crosses scales from global to regional to subregional and local. Resilient coastal communities and sustainable marine economies require actionable knowledge to plan for and adapt to emerging and potential future climate change, particularly in relation to ecosystem services and coastal hazards. Such knowledge necessarily draws heavily on coastal ocean modelling of future climate impacts, using a great diversity of both global and regional approaches to explore multiple societal challenges in coastal and shelf seas around the world. In this paper, we explore the challenges, solutions and benefits of developing a better coordinated and global approach to future climate impacts modelling of the coastal ocean, in the context of the UN Decade of Ocean Science for Sustainable Development project Future Coastal Ocean Climates (FLAME; part of the CoastPredict programme). Particularly, we address the need for diverse modelling approaches to meet different societal challenges, how regions can be harmonised through clustering and typology approaches, and how coordination of experimental designs can promote a better understanding of uncertainties and regional responses. Improved harmonisation of future climate impact projections in the global coastal ocean would allow sectoral and cross-sectoral global scale risk assessments, improve process understanding and help build capacity in under-represented areas such as the global south and small island developing states. We conclude with a proposed framework for a Global Coastal Ocean Model Intercomparison Project.