Drivers and uncertainties of future global marine primary production in marine ecosystem models

• Published in: Biogeosciences
• Main Authors: Laufkötter, Charlotte, Vogt, Meike, Gruber, Nicolas, Aita-Noguchi, M., Aumont, O., Bopp, Laurent, Buitenhuis, Erik T., Doney, Scott C., Dunne, John P., Hashioka, T., Hauck, Judith, Hirata, Takafumi, John, Jasmin G., Le Quéré, Corinne, Lima, Ivan D., Nakano, Hideyuki, Séférian, Roland, Totterdell, Ian J., Vichi, Marcello, Völker, Christoph
• Other Authors: Institute of Biogeochemistry and Pollutant Dynamics ETH Zürich (IBP), Department of Environmental Systems Science ETH Zürich (D-USYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Tyndall Centre for Climate Change Research, University of East Anglia Norwich (UEA), Woods Hole Oceanographic Institution (WHOI), University of Bristol Bristol, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Faculty of Environmental Earth Science Sapporo, Hokkaido University Sapporo, Japan, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office Exeter, Centro Euro-Mediterraneo per i Cambiamenti Climatici Bologna (CMCC), Department of Oceanography Cape Town, University of Cape Town
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Southern Ocean
• Online Access: https://hal.archives-ouvertes.fr/hal-01805260; https://hal.archives-ouvertes.fr/hal-01805260/document; https://hal.archives-ouvertes.fr/hal-01805260/file/bg-12-6955-2015.pdf; https://doi.org/10.5194/bg-12-6955-2015

International audience Past model studies have projected a global decrease in marine net primary production (NPP) over the 21st century, but these studies focused on the multi-model mean rather than on the large inter-model differences. Here, we analyze model-simulated changes in NPP for the 21st century under IPCC's high-emission scenario RCP8.5. We use a suite of nine coupled carbon-climate Earth system models with embedded marine ecosystem models and focus on the spread between the different models and the underlying reasons. Globally, NPP decreases in five out of the nine models over the course of the 21st century, while three show no significant trend and one even simulates an increase. The largest model spread occurs in the low latitudes (between 30 • S and 30 • N), with individual models simulating relative changes between −25 and +40 %. Of the seven models diagnosing a net decrease in NPP in the low latitudes, only three simulate this to be a consequence of the classical interpretation, i.e., a stronger nutrient limitation due to increased stratification leading to reduced phytoplankton growth. In the other four, warming-induced increases in phytoplankton growth outbal-ance the stronger nutrient limitation. However, temperature-driven increases in grazing and other loss processes cause a net decrease in phytoplankton biomass and reduce NPP despite higher growth rates. One model projects a strong increase in NPP in the low latitudes, caused by an inten-sification of the microbial loop, while NPP in the remaining model changes by less than 0.5 %. While models consistently project increases NPP in the Southern Ocean, the Published by Copernicus Publications on behalf of the European Geosciences Union. 6956 C. Laufkötter et al.: Drivers of future marine primary production regional inter-model range is also very substantial. In most models, this increase in NPP is driven by temperature, but it is also modulated by changes in light, macronutrients and iron as well as grazing. Overall, current projections of ...