Trophic amplification: A model intercomparison of climate driven changes in marine food webs

RESEARCH ARTICLE Trophic amplification: A model intercomparison of climate driven changes in marine food webs Vianney Guibourd de LuzinaisID1,2*, Hubert du Pontavice1,3, Gabriel Reygondeau2, Nicolas BarrierID4, Julia L. Blanchard5,6, Virginie Bornarel2, Matthias Bu¨ chnerID7, William W. L. Cheung2, Tyler D. Eddy8, Jason D. Everett9,10,11, Jerome Guiet12, Cheryl S. Harrison13, Olivier Maury4, Camilla Novaglio5,6, Colleen M. PetrikID14, Jeroen Steenbeek15, Derek P. Tittensor16, Didier Gascuel1 1 UMR Dynamics and Sustainability of Ecosystems: From Source to Sea (DECOD), Institut Agro, Ifremer, INRAE, Rennes, France, 2 Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada, 3 Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ, United States of America, 4 MARBEC, Univ. Montpellier, CNRS, Ifremer, IRD, Sète, France, 5 Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia, 6 Centre for Marine Socioecology, University of Tasmania, Hobart, TAS, Australia, 7 Potsdam-Institute for Climate Impact Research (PIK), Potsdam, Germany, 8 Centre for Fisheries Ecosystems Research, Fisheries & Marine Institute, Memorial University, St. John’s, NL, Canada, 9 School of Earth and Environmental Sciences, University of Queensland, Brisbane, QLD, Australia, 10 Centre for Marine Science and Innovation, School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW,

Australia, 11 Commonwealth Scientific and Industrial Research Organisation (CSIRO) Environment, Queensland Biosciences Precinct, St Lucia, QLD, Australia, 12 Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, United States of America, 13 Department of Coastal and Ocean Science and Center for Computation and Technology, Louisiana State University, Baton Rouge, LA, United States of America, 14 Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States of America, 15 Ecopath International Initiative, Barcelona, Spain, 16 Department of Biology, Dalhousie University, Halifax, NS, Canada * vianney.guibourddeluzinais@institut-agro.fr Abstract Marine animal biomass is expected to decrease in the 21st century due to climate driven changes in ocean environmental conditions. Previous studies suggest that the magnitude of the decline in primary production on apex predators could be amplified through the tropho- dynamics of marine food webs, leading to larger decreases in the biomass of predators rela- tive to the decrease in primary production, a mechanism called trophic amplification. We compared relative changes in producer and consumer biomass or production in the global ocean to assess the extent of trophic amplification. We used simulations from nine marine ecosystem models (MEMs) from the Fisheries and Marine Ecosystem Models Intercompari- son Project forced by two Earth System Models under the high greenhouse gas emissions

Shared Socioeconomic Pathways (SSP5-8.5) and a scenario of no fishing. Globally, total consumer biomass is projected to decrease by 16.7 ± 9.5% more than net primary produc- tion (NPP) by 2090–2099 relative to 1995–2014, with substantial variations among MEMs and regions. Total consumer biomass is projected to decrease almost everywhere in the ocean (80% of the world’s oceans) in the model ensemble. In 40% of the world’s oceans, consumer biomass was projected to decrease more than NPP. Additionally, in another 36% of the world’s oceans consumer biomass is expected to decrease even as projected NPP PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0287570 August 23, 2023 1 / 23 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Guibourd de Luzinais V, du Pontavice H, Reygondeau G, Barrier N, Blanchard JL, Bornarel V, et al. (2023) Trophic amplification: A model intercomparison of climate driven changes in marine food webs. PLoS ONE 18(8): e0287570. https://doi.org/10.1371/journal.pone.0287570 Editor: Vitor Hugo Rodrigues Paiva, MARE – Marine and Environmental Sciences Centre, PORTUGAL Received: July 29, 2022 Accepted: June 8, 2023 Published: August 23, 2023 Copyright: © 2023 Luzinais et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All standardized forcing variables from the ESMs are available at

https://doi.org/10.48364/ISIMIP.575744.1; all outputs from the MEMs are available via ISIMIP (https://www.isimip.org/gettingstarted/data- access/). Funding: This work has been conducted as part of a collaboration between L’Institut Agro, Rennes, and the University of British Columbia, Vancouver. Vianney Guibourd de Luzinais acknowledges