Life below the ocean surface increasingly threatened by climate change

Mr Isaac Brito-Morales^1,2, Dr David S. Schoeman^3,4, Dr Jorge García Molinos⁵, Dr Michael T. Burrows⁶, Dr Carissa J Klein¹, Dr Anthony J. Richardson^2,7

¹School of Earth and Environmental Sciences, The University Of Queensland, St Lucia, Australia, ²CSIRO Oceans and Atmosphere, BioSciences Precinct (QBP), St Lucia, Australia, ³School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Australia, ⁴Centre for African Conservation Ecology, Department of Zoology, Nelson Mandela University, Port Elizabeth, South Africa, ⁵Arctic Research Center, Hokkaido University, Hokkaido, Japan, ⁶Scottish Association for Marine Science, Oban, UK, ⁷Centre for Applications in Natural Resource Mathematics, School of Mathematics and Physics, The University of Queensland, St Lucia, Australia

In the ocean, evaluation of impacts of climate change on biodiversity have focused on the ocean surface. This is relevant for organisms living in the epipelagic zone, where the photic zone determines community structure, but might not be applicable to mesopelagic and bathypelagic communities. Using climate velocity and climate-velocity trajectories as metrics of potential range shifts, we explore how the distribution of marine species might change at different ocean depths under two IPCC Representative Concentration Pathways (RCP4.5 and RCP8.5), and potential implications for the global marine protected area (MPA) network. Projections show that climate velocity changes from the surface to the bottom of the ocean for both RCPs. Surface and intermediate layers show fast velocities, mainly around the equator and subtropical regions, while at the bottom climate velocity is patchier and slower than upper layers. Climate-velocity trajectories exhibit different climate connections at different depths for the global MPA network. Most of the global MPA network shows disconnections between contemporary climates and those under both climate-projection scenarios. Our results suggest that ranges of marine organisms at the surface and intermediate layers will have to shift at faster rates to maintain their climate niche compared with organisms on the seafloor, but that range shifts should nevertheless be expected in the deep oceans. This phenomenon is relevant because MPAs are fixed areas that have usually been projected vertically from the surface to the seafloor and organism at contrasting depths might respond differentially to changing climate in those areas.

Biography:

Isaac is a quantitative ecologist and a PhD candidate at the University of Queensland/CSIRO working on how the velocity of climate change might influence species’ distribution shifts at different ocean depths and how this phenomenon can inform conservation. He is exploring the resultant implications of his analysis for the global marine protected area network (MPA), both currently and under future climate change. His work aims to evaluate how climate change metrics (e.g. the velocity of climate change) can be effectively integrated into marine spatial planning.