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Tagliabue A, Barrier N, Du Pontavice H, Kwiatkowski L, Aumont O, Bopp L, Cheung WWL, Gascuel D, Maury O. An iron cycle cascade governs the response of equatorial Pacific ecosystems to climate change. Glob Chang Biol 2020; 26:6168-6179. [PMID: 32970390 DOI: 10.1111/gcb.15316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 05/24/2023]
Abstract
Earth System Models project that global climate change will reduce ocean net primary production (NPP), upper trophic level biota biomass and potential fisheries catches in the future, especially in the eastern equatorial Pacific. However, projections from Earth System Models are undermined by poorly constrained assumptions regarding the biological cycling of iron, which is the main limiting resource for NPP over large parts of the ocean. In this study, we show that the climate change trends in NPP and the biomass of upper trophic levels are strongly affected by modifying assumptions associated with phytoplankton iron uptake. Using a suite of model experiments, we find 21st century climate change impacts on regional NPP range from -12.3% to +2.4% under a high emissions climate change scenario. This wide range arises from variations in the efficiency of iron retention in the upper ocean in the eastern equatorial Pacific across different scenarios of biological iron uptake, which affect the strength of regional iron limitation. Those scenarios where nitrogen limitation replaced iron limitation showed the largest projected NPP declines, while those where iron limitation was more resilient displayed little future change. All model scenarios have similar skill in reproducing past inter-annual variations in regional ocean NPP, largely due to limited change in the historical period. Ultimately, projections of end of century upper trophic level biomass change are altered by 50%-80% across all plausible scenarios. Overall, we find that uncertainties in the biological iron cycle cascade through open ocean pelagic ecosystems, from plankton to fish, affecting their evolution under climate change. This highlights additional challenges to developing effective conservation and fisheries management policies under climate change.
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Affiliation(s)
| | - Nicolas Barrier
- MARBEC (IRD, Univ. Montpellier, CNRS, Ifremer), Sète, France
| | - Hubert Du Pontavice
- ESE, Ecology and Ecosystem Health, Institut Agro, Rennes, France
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC, Canada
| | | | - Olivier Aumont
- LOCEAN, Sorbonne Université-CNRS-IRD-MNHN, Paris, France
| | | | - William W L Cheung
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC, Canada
| | - Didier Gascuel
- ESE, Ecology and Ecosystem Health, Institut Agro, Rennes, France
| | - Olivier Maury
- MARBEC (IRD, Univ. Montpellier, CNRS, Ifremer), Sète, France
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Olmos M, Payne MR, Nevoux M, Prévost E, Chaput G, Du Pontavice H, Guitton J, Sheehan T, Mills K, Rivot E. Spatial synchrony in the response of a long range migratory species (Salmo salar) to climate change in the North Atlantic Ocean. Glob Chang Biol 2020; 26:1319-1337. [PMID: 31701595 DOI: 10.1111/gcb.14913] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 10/19/2019] [Indexed: 06/10/2023]
Abstract
A major challenge in understanding the response of populations to climate change is to separate the effects of local drivers acting independently on specific populations, from the effects of global drivers that impact multiple populations simultaneously and thereby synchronize their dynamics. We investigated the environmental drivers and the demographic mechanisms of the widespread decline in marine survival rates of Atlantic salmon (Salmo salar) over the last four decades. We developed a hierarchical Bayesian life cycle model to quantify the spatial synchrony in the marine survival of 13 large groups of populations (called stock units, SU) from two continental stock groups (CSG) in North America (NA) and Southern Europe (SE) over the period 1971-2014. We found strong coherence in the temporal variation in postsmolt marine survival among the 13 SU of NA and SE. A common North Atlantic trend explains 37% of the temporal variability of the survivals for the 13 SU and declines by a factor of 1.8 over the 1971-2014 time series. Synchrony in survival trends is stronger between SU within each CSG. The common trends at the scale of NA and SE capture 60% and 42% of the total variance of temporal variations, respectively. Temporal variations of the postsmolt survival are best explained by the temporal variations of sea surface temperature (SST, negative correlation) and net primary production indices (PP, positive correlation) encountered by salmon in common domains during their marine migration. Specifically, in the Labrador Sea/Grand Banks for populations from NA, 26% and 24% of variance is captured by SST and PP, respectively and in the Norwegian Sea for populations from SE, 21% and 12% of variance is captured by SST and PP, respectively. The findings support the hypothesis of a response of salmon populations to large climate-induced changes in the North Atlantic simultaneously impacting populations from distant continental habitats.
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Affiliation(s)
- Maxime Olmos
- UMR ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRAe, Rennes, France
- Management of Diadromous Fish in their Environment, AFB, INRAe, Agrocampus Ouest, UNIV PAU & PAYS ADOUR/E2S UPPA, Rennes, France
| | - Mark R Payne
- National Institute for Aquatic Resources, Technical University of Denmark (DTU-Aqua), Kongens Lyngby, Denmark
| | - Marie Nevoux
- UMR ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRAe, Rennes, France
- Management of Diadromous Fish in their Environment, AFB, INRAe, Agrocampus Ouest, UNIV PAU & PAYS ADOUR/E2S UPPA, Rennes, France
| | - Etienne Prévost
- Management of Diadromous Fish in their Environment, AFB, INRAe, Agrocampus Ouest, UNIV PAU & PAYS ADOUR/E2S UPPA, Rennes, France
- ECOBIOP, INRAe, Univ. Pau & Pays Adour/E2S, UPPA, Saint-Pée-sur-Nivelle, France
| | | | - Hubert Du Pontavice
- UMR ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRAe, Rennes, France
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, BC, Canada
| | - Jérôme Guitton
- UMR ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRAe, Rennes, France
| | - Timothy Sheehan
- Northeast Fisheries Science Center, National Marine Fisheries Service, Woods Hole, MA, USA
| | | | - Etienne Rivot
- UMR ESE, Ecology and Ecosystem Health, Agrocampus Ouest, INRAe, Rennes, France
- Management of Diadromous Fish in their Environment, AFB, INRAe, Agrocampus Ouest, UNIV PAU & PAYS ADOUR/E2S UPPA, Rennes, France
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Maureaud A, Gascuel D, Colléter M, Palomares MLD, Du Pontavice H, Pauly D, Cheung WWL. Global change in the trophic functioning of marine food webs. PLoS One 2017; 12:e0182826. [PMID: 28800358 PMCID: PMC5553640 DOI: 10.1371/journal.pone.0182826] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 07/25/2017] [Indexed: 11/28/2022] Open
Abstract
The development of fisheries in the oceans, and other human drivers such as climate warming, have led to changes in species abundance, assemblages, trophic interactions, and ultimately in the functioning of marine food webs. Here, using a trophodynamic approach and global databases of catches and life history traits of marine species, we tested the hypothesis that anthropogenic ecological impacts may have led to changes in the global parameters defining the transfers of biomass within the food web. First, we developed two indicators to assess such changes: the Time Cumulated Indicator (TCI) measuring the residence time of biomass within the food web, and the Efficiency Cumulated Indicator (ECI) quantifying the fraction of secondary production reaching the top of the trophic chain. Then, we assessed, at the large marine ecosystem scale, the worldwide change of these two indicators over the 1950–2010 time-periods. Global trends were identified and cluster analyses were used to characterize the variability of trends between ecosystems. Results showed that the most common pattern over the study period is a global decrease in TCI, while the ECI indicator tends to increase. Thus, changes in species assemblages would induce faster and apparently more efficient biomass transfers in marine food webs. Results also suggested that the main driver of change over that period had been the large increase in fishing pressure. The largest changes occurred in ecosystems where ‘fishing down the marine food web’ are most intensive.
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Affiliation(s)
- Aurore Maureaud
- Université Bretagne Loire, Agrocampus Ouest, UMR 985 Ecology and ecosystem health, Rennes, France
- * E-mail:
| | - Didier Gascuel
- Université Bretagne Loire, Agrocampus Ouest, UMR 985 Ecology and ecosystem health, Rennes, France
| | - Mathieu Colléter
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
- Sea Around Us, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Maria L. D. Palomares
- Sea Around Us, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Hubert Du Pontavice
- Université Bretagne Loire, Agrocampus Ouest, UMR 985 Ecology and ecosystem health, Rennes, France
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Daniel Pauly
- Sea Around Us, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
| | - William W. L. Cheung
- Nippon Foundation-Nereus Program, Institute for the Oceans and Fisheries, The University of British Columbia, Vancouver, British Columbia, Canada
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