CHAPTER 8 Marine biodiversity and ecosystem services: the large gloomy shadow of climate change Didier Gascuel 1 and William W.L. Cheung 2 1 Agrocampus Ouest, Ecology and Ecosystem Health Research Unit, Rennes, France 2 Changing Ocean Research Unit, The University of British Columbia, Vancouver, BC, Canada Chapter Outline 8.1 Introduction 79 8.2 Changing marine ecosystem and biodiversity: seven highlights 80 8.3 Global impact of climate change on marine ecosystems and the biodiversity 81 8.4 Impacts on marine ecosystem services 82 References 83 8.1 Introduction For decades, if not centuries, biodiversity in the global ocean has been under increasing pressure from human activities. Over the last century fisheries have been the main driver of global change in the sea, leading not only to the depletion of exploited stocks [13], but also to the degradation of the integrity of habitats in the seafloor [4,5], the truncation of age structure of exploited populations, and the modifications of species assemblages [6]. The impacts of fishing have affected the functioning of marine food webs [7,8] such as ecosystem productivity and the resilience of ecosystems [9,10]. In the last few decades the effects of climate change on the structure and the functioning of marine ecosystems have already been detected [11]. The poleward migration of fish stocks has been documented worldwide [12,13] and is expected to continue in the 21st century [14]. Moreover, ocean warming affects ocean primary production which consequently alters potential fisheries catches [15,16]. Ocean acidification and deoxygenation are expected to affect the productivity, abundance, and distribution of marine species, including those that are exploited by fisheries [17]. Altogether fishing and climate change are compromising ecosystem services provided by the ocean. 79 Predicting Future Oceans. DOI: https://doi.org/10.1016/B978-0-12-817945-1.00008-3 © 2019 Elsevier Inc. All rights reserved.