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Liu F, Li X, Luo Y, Cai W, Lu J, Zheng XT, Kang SM, Wang H, Zhou L. Increased Asian aerosols drive a slowdown of Atlantic Meridional Overturning Circulation. Nat Commun 2024; 15:18. [PMID: 38168125 PMCID: PMC10762259 DOI: 10.1038/s41467-023-44597-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Observational evidence and climate model experiments suggest a slowdown of the Atlantic Meridional Overturning Circulation (AMOC) since the mid-1990s. Increased greenhouse gases and the declined anthropogenic aerosols (AAs) over North America and Europe are believed to contribute to the AMOC slowdown. Asian AAs continue to increase but the associated impact has been unclear. Using ensembles of climate simulations, here we show that the radiative cooling resulting from increased Asian AAs drives an AMOC reduction. The increased AAs over Asia generate circumglobal stationary Rossby waves in the northern midlatitudes, which shift the westerly jet stream southward and weaken the subpolar North Atlantic westerlies. Consequently, reduced transport of cold air from North America hinders water mass transformation in the Labrador Sea and thus contributes to the AMOC slowdown. The link between increased Asian AAs and an AMOC slowdown is supported by different models with different configurations. Thus, reducing emissions of Asian AAs will not only lower local air pollution, but also help stabilize the AMOC.
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Affiliation(s)
- Fukai Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China.
| | - Xun Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China
| | - Yiyong Luo
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China.
| | - Wenju Cai
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China
- Laoshan Laboratory, Qingdao, China
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
- State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China
| | - Jian Lu
- Atmosphere, Climate, and Earth Sciences Division, Pacific Northwest National Laboratory, Richland, USA
| | - Xiao-Tong Zheng
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China
| | - Sarah M Kang
- Max Planck Institute for Meteorology, Hamburg, Germany
| | - Hai Wang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China
| | - Lei Zhou
- School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
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2
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Srokosz MA, Holliday NP, Bryden HL. Atlantic overturning: new observations and challenges. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220196. [PMID: 37866387 PMCID: PMC10590659 DOI: 10.1098/rsta.2022.0196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 10/24/2023]
Abstract
This paper provides an introduction to the special issue of the Philosophical Transactions of the Royal Society of London of papers from the 2022 Royal Society meeting on 'Atlantic overturning: new observations and challenges'. It provides the background and rationale for the meeting, briefly summarizes prior progress on observing the Atlantic overturning circulation and draws out the new challenges that papers presented at the meeting raise, so pointing the way forward for future research. This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
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Affiliation(s)
| | | | - Harry L. Bryden
- School of Ocean and Earth Science, University of Southampton, Empress Dock SO14 3ZH, UK
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3
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Lozier MS. Overturning in the subpolar North Atlantic: a review. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220191. [PMID: 37866384 PMCID: PMC10590667 DOI: 10.1098/rsta.2022.0191] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 06/14/2023] [Indexed: 10/24/2023]
Abstract
The Overturning in the Subpolar North Atlantic Program (OSNAP) was initiated in the spring of 2010 through a collaborative effort involving the USA, the UK, Germany, the Netherlands and Canada. A key feature of OSNAP is a trans-basin observing system deployed in the summer of 2014 for the continuous measure of volume, heat and freshwater fluxes in the subpolar North Atlantic. This review focuses on advancements made possible by the collective OSNAP observations. Chief among those advancements is the quantification of the dominant role of the eastern subpolar North Atlantic in the production of dense waters that reside in the lower limb of the overturning: the Irminger and Iceland basins contributed approximately three times as much dense water compared with the Labrador Sea over the observational period. Other advancements include elucidation of the relationship between convective activity in the basin interior and boundary current anomalies; the spread of overflow waters in the subpolar region; the seasonality of the meridional volume, heat and freshwater fluxes; and the challenges involved in designing a simpler, less costly observing system. Collectively, OSNAP measurements are laying a framework on which to assess the overturning circulation's vulnerability to continued warming and freshening as climate change continues apace. This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
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Affiliation(s)
- M. Susan Lozier
- Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
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4
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Frajka-Williams E, Foukal N, Danabasoglu G. Should AMOC observations continue: how and why? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220195. [PMID: 37866381 PMCID: PMC10590660 DOI: 10.1098/rsta.2022.0195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 06/20/2023] [Indexed: 10/24/2023]
Abstract
The Atlantic meridional overturning circulation (AMOC) is a large-scale circulation pattern responsible for northward heat transport in the Atlantic and is associated with climate variations on a wide range of time scales. Observing the time-varying AMOC has fundamentally changed our understanding of the large-scale ocean circulation and its interaction with the climate system, as well as identified shortcomings in numerical simulations. With a wide range of gains already achieved, some now ask whether AMOC observations should continue. A measured approach is required for a future observing system that addresses identified gaps in understanding, accounts for shortcomings in observing methods and maximizes the potential to guide improvements in ocean and climate models. Here, we outline a perspective on future AMOC observing and steps that the community should consider to move forward. This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
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Affiliation(s)
- E. Frajka-Williams
- Institut für Meereskunde, Universität Hamburg, 20148 Hamburg, Germany
- National Oceanography Centre, Southampton SO14 3ZH, UK
| | - N. Foukal
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - G. Danabasoglu
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
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5
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McCarthy GD, Caesar L. Can we trust projections of AMOC weakening based on climate models that cannot reproduce the past? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220193. [PMID: 37866378 PMCID: PMC10590661 DOI: 10.1098/rsta.2022.0193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/20/2023] [Indexed: 10/24/2023]
Abstract
The Atlantic Meridional Overturning Circulation (AMOC), a crucial element of the Earth's climate system, is projected to weaken over the course of the twenty-first century which could have far reaching consequences for the occurrence of extreme weather events, regional sea level rise, monsoon regions and the marine ecosystem. The latest IPCC report puts the likelihood of such a weakening as 'very likely'. As our confidence in future climate projections depends largely on the ability to model the past climate, we take an in-depth look at the difference in the twentieth century evolution of the AMOC based on observational data (including direct observations and various proxy data) and model data from climate model ensembles. We show that both the magnitude of the trend in the AMOC over different time periods and often even the sign of the trend differs between observations and climate model ensemble mean, with the magnitude of the trend difference becoming even greater when looking at the CMIP6 ensemble compared to CMIP5. We discuss possible reasons for this observation-model discrepancy and question what it means to have higher confidence in future projections than historical reproductions. This article is part of a discussion meeting issue 'Atlantic overturning: new observations and challenges'.
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Affiliation(s)
| | - Levke Caesar
- MARUM—Centre for Marine Environmental Sciences, University of Bremen,Bremen, Germany
- Institute of Environmental Physics, University of Bremen,Bremen, Germany
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6
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Possenti L, Reichart GJ, de Nooijer L, Lam FP, de Jong C, Colin M, Binnerts B, Boot A, von der Heydt A. Predicting the contribution of climate change on North Atlantic underwater sound propagation. PeerJ 2023; 11:e16208. [PMID: 37842042 PMCID: PMC10573315 DOI: 10.7717/peerj.16208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/08/2023] [Indexed: 10/17/2023] Open
Abstract
Since the industrial revolution, oceans have become substantially noisier. The noise increase is mainly caused by increased shipping, resource exploration, and infrastructure development affecting marine life at multiple levels, including behavior and physiology. Together with increasing anthropogenic noise, climate change is altering the thermal structure of the oceans, which in turn might affect noise propagation. During this century, we are witnessing an increase in seawater temperature and a decrease in ocean pH. Ocean acidification will decrease sound absorption at low frequencies (<10 kHz), enhancing long-range sound propagation. At the same time, temperature changes can modify the sound speed profile, leading to the creation or disappearance of sound ducts in which sound can propagate over large distances. The worldwide effect of climate change was explored for the winter and summer seasons using the (2018 to 2022) and (2094 to 2098, projected) atmospheric and seawater temperature, salinity, pH and wind speed as input. Using numerical modelling, we here explore the impact of climate change on underwater sound propagation. The future climate variables were taken from a Community Earth System Model v2 (CESM2) simulations forced under the concentration-driven SSP2-4.5 and SSP5-8.5 scenarios. The sound modeling results show, for future climate change scenarios, a global increase of sound speed at different depths (5, 125, 300, and 640 m) except for the North Atlantic Ocean and the Norwegian Sea, where in the upper 125 m sound speed will decrease by as much as 40 m s-1. This decrease in sound speed results in a new sub-surface duct in the upper 200 m of the water column allowing ship noise to propagate over large distances (>500 km). In the case of the Northeast Atlantic Ocean, this sub-surface duct will only be present during winter, leading to similar total mean square pressure level (SPLtot) values in the summer for both (2018 to 2022) and (2094 to 2098). We observed a strong and similar correlation for the two climate change scenarios, with an increase of the top 200 m SPLtot and a slowdown of Atlantic Meridional Overturning Circulation (AMOC) leading to an increase of SPLtot at the end of the century by 7 dB.
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Affiliation(s)
- Luca Possenti
- Ocean Systems (OCS), Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands
| | - Gert-Jan Reichart
- Ocean Systems (OCS), Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands
- Department of Earth Sciences—Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Lennart de Nooijer
- Ocean Systems (OCS), Royal Netherlands Institute for Sea Research (NIOZ), Texel, The Netherlands
| | - Frans-Peter Lam
- Acoustics & Sonar, Netherlands Organization for Applied Scientific Research (TNO), The Hague, The Netherlands
| | - Christ de Jong
- Acoustics & Sonar, Netherlands Organization for Applied Scientific Research (TNO), The Hague, The Netherlands
| | - Mathieu Colin
- Acoustics & Sonar, Netherlands Organization for Applied Scientific Research (TNO), The Hague, The Netherlands
| | - Bas Binnerts
- Acoustics & Sonar, Netherlands Organization for Applied Scientific Research (TNO), The Hague, The Netherlands
| | - Amber Boot
- Department of Physics, Institute for Marine and Atmospheric research Utrecht (IMAU)—Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna von der Heydt
- Department of Physics, Institute for Marine and Atmospheric research Utrecht (IMAU)—Faculty of Science, Utrecht University, Utrecht, The Netherlands
- Centre for Complex Systems Studies, Utrecht University, Utrecht, The Netherlands
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7
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Likely accelerated weakening of Atlantic overturning circulation emerges in optimal salinity fingerprint. Nat Commun 2023; 14:1245. [PMID: 36871075 PMCID: PMC9985640 DOI: 10.1038/s41467-023-36288-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 01/24/2023] [Indexed: 03/06/2023] Open
Abstract
The long-term response of the Atlantic meridional overturning circulation (AMOC) to anthropogenic forcing has been difficult to detect from the short direct measurements available due to strong interdecadal variability. Here, we present observational and modeling evidence for a likely accelerated weakening of the AMOC since the 1980s under the combined forcing of anthropogenic greenhouse gases and aerosols. This likely accelerated AMOC weakening signal can be detected in the AMOC fingerprint of salinity pileup remotely in the South Atlantic, but not in the classic warming hole fingerprint locally in the North Atlantic, because the latter is contaminated by the "noise" of interdecadal variability. Our optimal salinity fingerprint retains much of the signal of the long-term AMOC trend response to anthropogenic forcing, while dynamically filtering out shorter climate variability. Given the ongoing anthropogenic forcing, our study indicates a potential further acceleration of AMOC weakening with associated climate impacts in the coming decades.
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8
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Timing of emergence of modern rates of sea-level rise by 1863. Nat Commun 2022; 13:966. [PMID: 35181652 PMCID: PMC8857177 DOI: 10.1038/s41467-022-28564-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 01/26/2022] [Indexed: 11/08/2022] Open
Abstract
Sea-level rise is a significant indicator of broader climate changes, and the time of emergence concept can be used to identify when modern rates of sea-level rise emerged above background variability. Yet a range of estimates of the timing persists both globally and regionally. Here, we use a global database of proxy sea-level records of the Common Era (0–2000 CE) and show that globally, it is very likely that rates of sea-level rise emerged above pre-industrial rates by 1863 CE (P = 0.9; range of 1825 [P = 0.66] to 1873 CE [P = 0.95]), which is similar in timing to evidence for early ocean warming and glacier melt. The time of emergence in the North Atlantic reveals a distinct spatial pattern, appearing earliest in the mid-Atlantic region (1872–1894 CE) and later in Canada and Europe (1930–1964 CE). Regional and local sea-level changes occurring over different time periods drive the spatial pattern in emergence, suggesting regional processes underlie centennial-timescale sea-level variability over the Common Era. Sea-level rise is a significant indicator of climate changes and it is important to identify the time of emergence of modern rates of sea-level rise. Here the authors estimate that global sea-level rise emerged by 1863 and find spatial variability of emergence at sites within the North Atlantic.
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9
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Rackow T, Danilov S, Goessling HF, Hellmer HH, Sein DV, Semmler T, Sidorenko D, Jung T. Delayed Antarctic sea-ice decline in high-resolution climate change simulations. Nat Commun 2022; 13:637. [PMID: 35110565 PMCID: PMC8810850 DOI: 10.1038/s41467-022-28259-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 01/16/2022] [Indexed: 11/10/2022] Open
Abstract
Despite global warming and Arctic sea-ice loss, on average the Antarctic sea-ice extent has not declined since 1979 when satellite data became available. In contrast, climate model simulations tend to exhibit strong negative sea-ice trends for the same period. This Antarctic sea-ice paradox leads to low confidence in 21st-century sea-ice projections. Here we present multi-resolution climate change projections that account for Southern Ocean mesoscale eddies. The high-resolution configuration simulates stable September Antarctic sea-ice extent that is not projected to decline until the mid-21st century. We argue that one reason for this finding is a more realistic ocean circulation that increases the equatorward heat transport response to global warming. As a result, the ocean becomes more efficient at moderating the anthropogenic warming around Antarctica and hence at delaying sea-ice decline. Our study suggests that explicitly simulating Southern Ocean eddies is necessary for providing Antarctic sea-ice projections with higher confidence.
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Affiliation(s)
- Thomas Rackow
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
- European Centre for Medium-Range Weather Forecasts, Bonn, Germany.
| | - Sergey Danilov
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Jacobs University Bremen, Bremen, Germany
| | - Helge F Goessling
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Hartmut H Hellmer
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Dmitry V Sein
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Moscow, Russia
| | - Tido Semmler
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Dmitry Sidorenko
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Thomas Jung
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- Institute of Environmental Physics, University of Bremen, Bremen, Germany
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10
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Bryden HL. Wind-driven and buoyancy-driven circulation in the subtropical North Atlantic Ocean. Proc Math Phys Eng Sci 2021; 477:20210172. [PMID: 35153601 PMCID: PMC8655619 DOI: 10.1098/rspa.2021.0172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 11/05/2021] [Indexed: 11/12/2022] Open
Abstract
Continuous observations of ocean circulation at 26°N in the subtropical Atlantic Ocean have been made since April 2004 to quantify the strength and variability in the Atlantic Meridional overturning circulation (AMOC), in which warm, upper waters flow northward and colder deep waters below 1100 m depth return southward. The principal components of the AMOC are northward western boundary current transport in the Gulf Stream and Antilles Current, northward surface Ekman transport and southward thermocline recirculation, all of which are generally considered to be part of the wind-driven circulation. Southward flowing deep waters below 1100 m depth are usually considered to represent the buoyancy-driven circulation. We argue that the Gulf Stream is partially wind-driven but also partially buoyancy-driven as it returns upper waters upwelled in the global ocean back to water mass formation regions in the northern Atlantic. Seasonal to interannual variations in the circulation at 26°N are principally wind-driven. Variability in the buoyancy-driven circulation occurred in a sharp reduction in 2009 in the southward flow of Lower North Atlantic Deep Water when its transport decreased by 30% from pre-2009 values. Over the 14-year observational period from 2004 to 2018, the AMOC declined by 2.4 Sv from 18.3 to 15.9 Sv.
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Affiliation(s)
- Harry L. Bryden
- School of Ocean and Earth Science, University of Southampton, Empress Dock, Southampton SO14 3ZH, UK
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11
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Heinze C, Blenckner T, Martins H, Rusiecka D, Döscher R, Gehlen M, Gruber N, Holland E, Hov Ø, Joos F, Matthews JBR, Rødven R, Wilson S. The quiet crossing of ocean tipping points. Proc Natl Acad Sci U S A 2021; 118:e2008478118. [PMID: 33619085 PMCID: PMC7936299 DOI: 10.1073/pnas.2008478118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Anthropogenic climate change profoundly alters the ocean's environmental conditions, which, in turn, impact marine ecosystems. Some of these changes are happening fast and may be difficult to reverse. The identification and monitoring of such changes, which also includes tipping points, is an ongoing and emerging research effort. Prevention of negative impacts requires mitigation efforts based on feasible research-based pathways. Climate-induced tipping points are traditionally associated with singular catastrophic events (relative to natural variations) of dramatic negative impact. High-probability high-impact ocean tipping points due to warming, ocean acidification, and deoxygenation may be more fragmented both regionally and in time but add up to global dimensions. These tipping points in combination with gradual changes need to be addressed as seriously as singular catastrophic events in order to prevent the cumulative and often compounding negative societal and Earth system impacts.
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Affiliation(s)
- Christoph Heinze
- Geophysical Institute, University of Bergen, 5020 Bergen, Norway;
- Bjerknes Centre for Climate Research, University of Bergen, 5020 Bergen, Norway
| | - Thorsten Blenckner
- Stockholm Resilience Centre, Stockholm University, 10691 Stockholm, Sweden
| | - Helena Martins
- Rossby Centre, Swedish Meteorological and Hydrological Institute, 60176 Norrköping, Sweden
| | - Dagmara Rusiecka
- Geophysical Institute, University of Bergen, 5020 Bergen, Norway
- Bjerknes Centre for Climate Research, University of Bergen, 5020 Bergen, Norway
| | - Ralf Döscher
- Rossby Centre, Swedish Meteorological and Hydrological Institute, 60176 Norrköping, Sweden
| | - Marion Gehlen
- Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre Simon Laplace, 91191 Gif-sur-Yvette cedex, France
| | - Nicolas Gruber
- Institute of Biogeochemistry and Pollutant Dynamics, Eidgenössische Technische Hochschule (ETH) Zürich, 8092 Zürich, Switzerland
| | - Elisabeth Holland
- Pacific Centre for the Environment and Sustainable Development, The University of the South Pacific, Suva, Fiji
| | - Øystein Hov
- Norwegian Meteorological Institute, 0371 Oslo, Norway
- The Norwegian Academy of Science and Letters, 0271 Oslo, Norway
| | - Fortunat Joos
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - John Brian Robin Matthews
- School of Architecture, Computing and Engineering, University of East London, E16 2RD, London, United Kingdom
| | - Rolf Rødven
- Arctic Monitoring and Assessment Programme Secretariat, 9296 Tromsø, Norway
| | - Simon Wilson
- Arctic Monitoring and Assessment Programme Secretariat, 9296 Tromsø, Norway
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12
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Fu Y, Li F, Karstensen J, Wang C. A stable Atlantic Meridional Overturning Circulation in a changing North Atlantic Ocean since the 1990s. SCIENCE ADVANCES 2020; 6:6/48/eabc7836. [PMID: 33246958 PMCID: PMC7695472 DOI: 10.1126/sciadv.abc7836] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 10/14/2020] [Indexed: 06/12/2023]
Abstract
The Atlantic Meridional Overturning Circulation (AMOC) is crucially important to global climate. Model simulations suggest that the AMOC may have been weakening over decades. However, existing array-based AMOC observations are not long enough to capture multidecadal changes. Here, we use repeated hydrographic sections in the subtropical and subpolar North Atlantic, combined with an inverse model constrained using satellite altimetry, to jointly analyze AMOC and hydrographic changes over the past three decades. We show that the AMOC state in the past decade is not distinctly different from that in the 1990s in the North Atlantic, with a remarkably stable partition of the subpolar overturning occurring prominently in the eastern basins rather than in the Labrador Sea. In contrast, profound hydrographic and oxygen changes, particularly in the subpolar North Atlantic, are observed over the same period, suggesting a much higher decoupling between the AMOC and ocean interior property fields than previously thought.
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Affiliation(s)
- Yao Fu
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China
| | - Feili Li
- Georgia Institute of Technology, Atlanta, GA, USA.
| | | | - Chunzai Wang
- State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China.
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
- Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou, China
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13
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Abstract
Climate change is the most important contemporary environmental problem that the world faces, yet it is the subject of many misconceptions. Climate science has been used for political ends and distorted in the press, both intentionally and through ignorance. This article presents an overview of what is known about global warming and what is controversial, about future climate projections and their impacts, and about the emissions responsible for climate change and policies to limit them.
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Affiliation(s)
- Helen M. Cox
- Institute for Sustainability and Associate Professor, Geography California State University, Northridge, CA 91330
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14
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Madrigal-González J, Andivia E, Zavala MA, Stoffel M, Calatayud J, Sánchez-Salguero R, Ballesteros-Cánovas J. Disentangling the relative role of climate change on tree growth in an extreme Mediterranean environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 642:619-628. [PMID: 29909329 DOI: 10.1016/j.scitotenv.2018.06.064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/05/2018] [Accepted: 06/06/2018] [Indexed: 06/08/2023]
Abstract
Climate change can impair ecosystem functions and services in extensive dry forests worldwide. However, attribution of climate change impacts on tree growth and forest productivity is challenging due to multiple inter-annual patterns of climatic variability associated with atmospheric and oceanic circulations. Moreover, growth responses to rising atmospheric CO2, namely carbon fertilization, as well as size ontogenetic changes can obscure the climate change signature as well. Here we apply Structural Equation Models (SEM) to investigate the relative role of climate change on tree growth in an extreme Mediterranean environment (i.e., extreme in terms of the combination of sandy-unconsolidated soils and climatic aridity). Specifically, we analyzed potential direct and indirect pathways by which different sources of climatic variability (i.e. warming and precipitation trends, the North Atlantic Oscillation, [NAO]; the Mediterranean Oscillation, [MOI]; the Atlantic Mediterranean Oscillation, [AMO]) affect aridity through their control on local climate (in terms of mean annual temperature and total annual precipitation), and subsequently tree productivity, in terms of basal area increments (BAI). Our results support the predominant role of Diameter at Breast Height (DHB) as the main growth driver. In terms of climate, NAO and AMO are the most important drivers of tree growth through their control of aridity (via effects of precipitation and temperature, respectively). Furthermore and contrary to current expectations, our findings also support a net positive role of climate warming on growth over the last 50 years and suggest that impacts of climate warming should be evaluated considering multi-annual and multi-decadal periods of local climate defined by atmospheric and oceanic circulation in the North Atlantic.
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Affiliation(s)
- Jaime Madrigal-González
- Grupo de Ecología y Restauración Forestal, Departamento de Ciencias de la Vida, Universidad de Alcalá, ctra. Madrid-Barcelona, km 33.4, 28805, Alcalá de Henares, Spain; Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences (IES), University of Geneva, 66 Boulevard Carl-Vogt, CH-1205, Switzerland.
| | - Enrique Andivia
- Grupo de Ecología y Restauración Forestal, Departamento de Ciencias de la Vida, Universidad de Alcalá, ctra. Madrid-Barcelona, km 33.4, 28805, Alcalá de Henares, Spain
| | - Miguel A Zavala
- Grupo de Ecología y Restauración Forestal, Departamento de Ciencias de la Vida, Universidad de Alcalá, ctra. Madrid-Barcelona, km 33.4, 28805, Alcalá de Henares, Spain
| | - Markus Stoffel
- Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences (IES), University of Geneva, 66 Boulevard Carl-Vogt, CH-1205, Switzerland; Dendrolab, Department of Earth Sciences, University of Geneva, rue des Maraîchers 13, CH-1205 Geneva, Switzerland; Department F.-A, Forel for Aquatic and Environmental Sciences, University of Geneva, 66 Boulevard Carl-Vogt, CH-1205, Switzerland
| | - Joaquín Calatayud
- Integrated Science Lab, Department of Physics, Umeå University, 901 87 Umeå, Sweden
| | - Raúl Sánchez-Salguero
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. Utrera, km 1, 41013 Sevilla, Spain
| | - Juan Ballesteros-Cánovas
- Climate Change Impacts and Risks in the Anthropocene (C-CIA), Institute for Environmental Sciences (IES), University of Geneva, 66 Boulevard Carl-Vogt, CH-1205, Switzerland; Dendrolab, Department of Earth Sciences, University of Geneva, rue des Maraîchers 13, CH-1205 Geneva, Switzerland
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15
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Howe JNW, Piotrowski AM. Atlantic deep water provenance decoupled from atmospheric CO 2 concentration during the lukewarm interglacials. Nat Commun 2017; 8:2003. [PMID: 29222483 PMCID: PMC5722826 DOI: 10.1038/s41467-017-01939-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 10/26/2017] [Indexed: 11/09/2022] Open
Abstract
Ice core records show that atmospheric CO2 concentrations and Antarctic temperature were lower during the ‘lukewarm interglacials’ from 800 to 430 ka than the subsequent five interglacials. These different interglacial ‘strengths’ have been hypothesised to be controlled by Antarctic overturning circulation. How these variations in Antarctic overturning relate to Northern Atlantic overturning circulation, a major driver of Northern Hemisphere climate, is uncertain. Here we present a high-resolution record of authigenic neodymium isotopes—a water mass tracer that is independent of biological processes—and use it to reconstruct Atlantic overturning circulation during the last 800 kyr. This record reveals a similar proportion of North Atlantic Deep Water during the ‘lukewarm interglacials’ and the more recent interglacials. This observation suggests that the provenance of deep water in the Atlantic Ocean can be decoupled from ventilation state of the Southern Ocean and consequently the atmospheric concentration of carbon dioxide. How deep ocean circulation is linked to changes in atmospheric CO2 concentration remains uncertain. Here, the authors show that deep equatorial Atlantic Ocean water mass provenance was similar throughout all interglacials of the past 800 kyr, despite variable interglacial atmospheric CO2 concentrations.
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Affiliation(s)
- Jacob N W Howe
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK.
| | - Alexander M Piotrowski
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK
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16
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Cao Y, Liang S, Chen X, He T, Wang D, Cheng X. Enhanced wintertime greenhouse effect reinforcing Arctic amplification and initial sea-ice melting. Sci Rep 2017; 7:8462. [PMID: 28814806 PMCID: PMC5559487 DOI: 10.1038/s41598-017-08545-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 07/14/2017] [Indexed: 11/09/2022] Open
Abstract
The speeds of both Arctic surface warming and sea-ice shrinking have accelerated over recent decades. However, the causes of this unprecedented phenomenon remain unclear and are subjects of considerable debate. In this study, we report strong observational evidence, for the first time from long-term (1984-2014) spatially complete satellite records, that increased cloudiness and atmospheric water vapor in winter and spring have caused an extraordinary downward longwave radiative flux to the ice surface, which may then amplify the Arctic wintertime ice-surface warming. In addition, we also provide observed evidence that it is quite likely the enhancement of the wintertime greenhouse effect caused by water vapor and cloudiness has advanced the time of onset of ice melting in mid-May through inhibiting sea-ice refreezing in the winter and accelerating the pre-melting process in the spring, and in turn triggered the positive sea-ice albedo feedback process and accelerated the sea ice melting in the summer.
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Affiliation(s)
- Yunfeng Cao
- The College of Forestry, Beijing Forestry University, 100083, Beijing, China
| | - Shunlin Liang
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA.
| | - Xiaona Chen
- Department of Hydraulic Engineering, Tsinghua University, Beijing, China
| | - Tao He
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, Hubei, 430079, China
| | - Dongdong Wang
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA
| | - Xiao Cheng
- State Key Laboratory of Remote Sensing Science, and College of Global Change and Earth System Science, Beijing Normal University, 100875, Beijing, China
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17
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Sgubin G, Swingedouw D, Drijfhout S, Mary Y, Bennabi A. Abrupt cooling over the North Atlantic in modern climate models. Nat Commun 2017; 8:ncomms14375. [PMID: 28198383 PMCID: PMC5330854 DOI: 10.1038/ncomms14375] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 12/21/2016] [Indexed: 11/29/2022] Open
Abstract
Observations over the 20th century evidence no long-term warming in the subpolar North Atlantic (SPG). This region even experienced a rapid cooling around 1970, raising a debate over its potential reoccurrence. Here we assess the risk of future abrupt SPG cooling in 40 climate models from the fifth Coupled Model Intercomparison Project (CMIP5). Contrary to the long-term SPG warming trend evidenced by most of the models, 17.5% of the models (7/40) project a rapid SPG cooling, consistent with a collapse of the local deep-ocean convection. Uncertainty in projections is associated with the models’ varying capability in simulating the present-day SPG stratification, whose realistic reproduction appears a necessary condition for the onset of a convection collapse. This event occurs in 45.5% of the 11 models best able to simulate the observed SPG stratification. Thus, due to systematic model biases, the CMIP5 ensemble as a whole underestimates the chance of future abrupt SPG cooling, entailing crucial implications for observation and adaptation policy. Concerns on climate change include the risk of abrupt cooling in the North Atlantic. Here, the authors analyse CMIP5 projections and show that a convection collapse in the subpolar gyre can cool this region by up to 3°C in 10 years, which is as likely to occur by 2100 as a continuous warming.
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Affiliation(s)
- Giovanni Sgubin
- Laboratoire des Sciences du Climat et de l'Environnement (LSCE), Institut Pierre Simon Laplace (IPSL), 91191 Gif-sur-Yvette, France.,Environnements et Paleoenvironnements Oceaniques et Continenteaux (EPOC), UMR CNRS 5805, Université de Bordeaux, 33615 Pessac, France
| | - Didier Swingedouw
- Environnements et Paleoenvironnements Oceaniques et Continenteaux (EPOC), UMR CNRS 5805, Université de Bordeaux, 33615 Pessac, France
| | - Sybren Drijfhout
- Royal Netherlands Meteorological Institute (KNMI), 3730AE De Bilt, The Netherlands.,National Oceanography Centre (NOC), University of Southampton, Southampton SO14 3ZH, UK
| | - Yannick Mary
- Environnements et Paleoenvironnements Oceaniques et Continenteaux (EPOC), UMR CNRS 5805, Université de Bordeaux, 33615 Pessac, France
| | - Amine Bennabi
- Institut de Mecanique et d'Ingenierie (I2M), Université de Bordeaux, 33615 Pessac, France
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18
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Talley LD, Feely RA, Sloyan BM, Wanninkhof R, Baringer MO, Bullister JL, Carlson CA, Doney SC, Fine RA, Firing E, Gruber N, Hansell DA, Ishii M, Johnson GC, Katsumata K, Key RM, Kramp M, Langdon C, Macdonald AM, Mathis JT, McDonagh EL, Mecking S, Millero FJ, Mordy CW, Nakano T, Sabine CL, Smethie WM, Swift JH, Tanhua T, Thurnherr AM, Warner MJ, Zhang JZ. Changes in Ocean Heat, Carbon Content, and Ventilation: A Review of the First Decade of GO-SHIP Global Repeat Hydrography. ANNUAL REVIEW OF MARINE SCIENCE 2015; 8:185-215. [PMID: 26515811 DOI: 10.1146/annurev-marine-052915-100829] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Global ship-based programs, with highly accurate, full water column physical and biogeochemical observations repeated decadally since the 1970s, provide a crucial resource for documenting ocean change. The ocean, a central component of Earth's climate system, is taking up most of Earth's excess anthropogenic heat, with about 19% of this excess in the abyssal ocean beneath 2,000 m, dominated by Southern Ocean warming. The ocean also has taken up about 27% of anthropogenic carbon, resulting in acidification of the upper ocean. Increased stratification has resulted in a decline in oxygen and increase in nutrients in the Northern Hemisphere thermocline and an expansion of tropical oxygen minimum zones. Southern Hemisphere thermocline oxygen increased in the 2000s owing to stronger wind forcing and ventilation. The most recent decade of global hydrography has mapped dissolved organic carbon, a large, bioactive reservoir, for the first time and quantified its contribution to export production (∼20%) and deep-ocean oxygen utilization. Ship-based measurements also show that vertical diffusivity increases from a minimum in the thermocline to a maximum within the bottom 1,500 m, shifting our physical paradigm of the ocean's overturning circulation.
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Affiliation(s)
- L D Talley
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093; ,
| | - R A Feely
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
| | - B M Sloyan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart, Tasmania 7001, Australia;
| | - R Wanninkhof
- Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, Florida 33149; , ,
| | - M O Baringer
- Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, Florida 33149; , ,
| | - J L Bullister
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
| | - C A Carlson
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, Santa Barbara, California 93106;
| | - S C Doney
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; ,
| | - R A Fine
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149; , , ,
| | - E Firing
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, Hawaii 96822;
| | - N Gruber
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich 8092, Switzerland;
| | - D A Hansell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149; , , ,
| | - M Ishii
- Meteorological Research Institute, Japan Meteorological Agency, Tsukuba 305-0052, Japan;
| | - G C Johnson
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
| | - K Katsumata
- Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka 237-0061, Japan;
| | - R M Key
- Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, New Jersey 08544;
| | - M Kramp
- JCOMM in-situ Observations Programme Support Center (JCOMMOPS), Technopôle Brest Iroise, Plouzané 29280, France;
| | - C Langdon
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149; , , ,
| | - A M Macdonald
- Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543; ,
| | - J T Mathis
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
| | - E L McDonagh
- National Oceanography Centre, Southampton SO14 3ZH, United Kingdom;
| | - S Mecking
- Applied Physics Laboratory, University of Washington, Seattle, Washington 98105;
| | - F J Millero
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, Florida 33149; , , ,
| | - C W Mordy
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
- Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington 98195;
| | - T Nakano
- Japan Meteorological Agency, Tokyo 100-8122, Japan;
| | - C L Sabine
- Pacific Marine Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115; , , , ,
| | - W M Smethie
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964; ,
| | - J H Swift
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093; ,
| | - T Tanhua
- GEOMAR Helmholtz Centre for Ocean Research Kiel, 24015 Kiel, Germany;
| | - A M Thurnherr
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964; ,
| | - M J Warner
- School of Oceanography, University of Washington, Seattle, Washington 98195;
| | - J-Z Zhang
- Atlantic Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric Administration, Miami, Florida 33149; , ,
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19
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Srokosz MA, Bryden HL. OCEAN CIRCULATION. Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises. Science 2015; 348:1255575. [PMID: 26089521 DOI: 10.1126/science.1255575] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The importance of the Atlantic Meridional Overturning Circulation (AMOC) heat transport for climate is well acknowledged. Climate models predict that the AMOC will slow down under global warming, with substantial impacts, but measurements of ocean circulation have been inadequate to evaluate these predictions. Observations over the past decade have changed that situation, providing a detailed picture of variations in the AMOC. These observations reveal a surprising degree of AMOC variability in terms of the intraannual range, the amplitude and phase of the seasonal cycle, the interannual changes in strength affecting the ocean heat content, and the decline of the AMOC over the decade, both of the latter two exceeding the variations seen in climate models.
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Affiliation(s)
- M A Srokosz
- National Oceanography Centre, University of Southampton Waterfront Campus, Southampton, UK.
| | - H L Bryden
- National Oceanography Centre Southampton, University of Southampton, Southampton, UK
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20
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Nguyen HM, Rountrey AN, Meeuwig JJ, Coulson PG, Feng M, Newman SJ, Waite AM, Wakefield CB, Meekan MG. Growth of a deep-water, predatory fish is influenced by the productivity of a boundary current system. Sci Rep 2015; 5:9044. [PMID: 25761975 PMCID: PMC4356959 DOI: 10.1038/srep09044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/10/2015] [Indexed: 11/17/2022] Open
Abstract
The effects of climate change on predatory fishes in deep shelf areas are difficult to predict because complex processes may govern food availability and temperature at depth. We characterised the net impact of recent environmental changes on hapuku (Polyprion oxygeneios), an apex predator found in continental slope habitats (>200 m depth) by using dendrochronology techniques to develop a multi-decadal record of growth from otoliths. Fish were sampled off temperate south-western Australia, a region strongly influenced by the Leeuwin Current, a poleward-flowing, eastern boundary current. The common variance among individual growth records was relatively low (3.4%), but the otolith chronology was positively correlated (r = 0.61, p < 0.02) with sea level at Fremantle, a proxy for the strength of the Leeuwin Current. The Leeuwin Current influences the primary productivity of shelf ecosystems, with a strong current favouring growth in hapuku. Leeuwin Current strength is predicted to decline under climate change models and this study provides evidence that associated productivity changes may flow through to higher trophic levels even in deep water habitats.
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Affiliation(s)
- Hoang Minh Nguyen
- School of Animal Biology, University of Western Australia, Crawley WA, Australia
| | - Adam N Rountrey
- 1] Centre for Marine Futures, Oceans Institute, University of Western Australia, Crawley WA, Australia [2] Museum of Paleontology, University of Michigan, Ann Arbor MI, USA
| | - Jessica J Meeuwig
- 1] School of Animal Biology, University of Western Australia, Crawley WA, Australia [2] Centre for Marine Futures, Oceans Institute, University of Western Australia, Crawley WA, Australia
| | - Peter G Coulson
- Centre for Fish and Fisheries Research, School of Veterinary and Life Sciences, Murdoch University, Murdoch WA, Australia
| | - Ming Feng
- CSIRO Oceans &Atmosphere Flagship, Underwood Avenue, Floreat, WA 6014, Australia
| | - Stephen J Newman
- Western Australian Fisheries and Marine Research Laboratories, Department of Fisheries, Government of Western AustraliaPO Box 20, North Beach, WA 6920, Australia
| | - Anya M Waite
- School of Civil, Environmental and Mining Engineering, University of Western Australia, Crawley WA, Australia
| | - Corey B Wakefield
- Western Australian Fisheries and Marine Research Laboratories, Department of Fisheries, Government of Western AustraliaPO Box 20, North Beach, WA 6920, Australia
| | - Mark G Meekan
- Australian Institute of Marine Science, Crawley WA, Australia
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21
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Lind L, Nilsson C, Weber C. Effects of ice and floods on vegetation in streams in cold regions: implications for climate change. Ecol Evol 2014; 4:4173-84. [PMID: 25505542 PMCID: PMC4242568 DOI: 10.1002/ece3.1283] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/01/2014] [Accepted: 09/23/2014] [Indexed: 11/09/2022] Open
Abstract
Riparian zones support some of the most dynamic and species-rich plant communities in cold regions. A common conception among plant ecologists is that flooding during the season when plants are dormant generally has little effect on the survival and production of riparian vegetation. We show that winter floods may also be of fundamental importance for the composition of riverine vegetation. We investigated the effects of ice formation on riparian and in-stream vegetation in northern Sweden using a combination of experiments and observations in 25 reaches, spanning a gradient from ice-free to ice-rich reaches. The ice-rich reaches were characterized by high production of frazil and anchor ice. In a couple of experiments, we exposed riparian vegetation to experimentally induced winter flooding, which reduced the dominant dwarf-shrub cover and led to colonization of a species-rich forb-dominated vegetation. In another experiment, natural winter floods caused by anchor-ice formation removed plant mimics both in the in-stream and in the riparian zone, further supporting the result that anchor ice maintains dynamic plant communities. With a warmer winter climate, ice-induced winter floods may first increase in frequency because of more frequent shifts between freezing and thawing during winter, but further warming and shortening of the winter might make them less common than today. If ice-induced winter floods become reduced in number because of a warming climate, an important disturbance agent for riparian and in-stream vegetation will be removed, leading to reduced species richness in streams and rivers in cold regions. Given that such regions are expected to have more plant species in the future because of immigration from the south, the distribution of species richness among habitats can be expected to show novel patterns.
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Affiliation(s)
- Lovisa Lind
- Landscape Ecology Group, Department of Ecology and Environmental Science, Umeå University SE-901 87, Umeå, Sweden
| | - Christer Nilsson
- Landscape Ecology Group, Department of Ecology and Environmental Science, Umeå University SE-901 87, Umeå, Sweden
| | - Christine Weber
- Eawag: Swiss Federal Institute of Aquatic Science and Technology Seestrasse 79, CH-6047, Kastanienbaum, Switzerland
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22
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Dunstone NJ. A perspective on sustained marine observations for climate modelling and prediction. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:rsta.2013.0340. [PMID: 25157195 PMCID: PMC4150295 DOI: 10.1098/rsta.2013.0340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Here, I examine some of the many varied ways in which sustained global ocean observations are used in numerical modelling activities. In particular, I focus on the use of ocean observations to initialize predictions in ocean and climate models. Examples are also shown of how models can be used to assess the impact of both current ocean observations and to simulate that of potential new ocean observing platforms. The ocean has never been better observed than it is today and similarly ocean models have never been as capable at representing the real ocean as they are now. However, there remain important unanswered questions that can likely only be addressed via future improvements in ocean observations. In particular, ocean observing systems need to respond to the needs of the burgeoning field of near-term climate predictions. Although new ocean observing platforms promise exciting new discoveries, there is a delicate balance to be made between their funding and that of the current ocean observing system. Here, I identify the need to secure long-term funding for ocean observing platforms as they mature, from a mainly research exercise to an operational system for sustained observation over climate change time scales. At the same time, considerable progress continues to be made via ship-based observing campaigns and I highlight some that are dedicated to addressing uncertainties in key ocean model parametrizations. The use of ocean observations to understand the prominent long time scale changes observed in the North Atlantic is another focus of this paper. The exciting first decade of monitoring of the Atlantic meridional overturning circulation by the RAPID-MOCHA array is highlighted. The use of ocean and climate models as tools to further probe the drivers of variability seen in such time series is another exciting development. I also discuss the need for a concerted combined effort from climate models and ocean observations in order to understand the current slow-down in surface global warming.
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23
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Frajka-Williams E. Sustaining observations of the unsteady ocean circulation. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:rsta.2013.0335. [PMID: 25157191 DOI: 10.1098/rsta.2013.0335] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Sustained observations of ocean properties reveal a global warming trend and rising sea levels. These changes have been documented by traditional ship-based measurements of ocean properties, whereas more recent Argo profiling floats and satellite records permit estimates of ocean changes on a near real-time basis. Through these and newer methods of observing the oceans, scientists are moving from quantifying the 'state of the ocean' to monitoring its variability, and distinguishing the physical processes bringing signals of change. In this paper, I give a brief overview of the UK contributions to the physical oceanographic observations, and the role they have played in the wider global observing systems. While temperature and salinity are the primary measurements of physical oceanography, new transbasin mooring arrays also resolve changes in ocean circulation on daily timescales. Emerging technologies permit routine observations at higher-than-ever spatial resolutions. Following this, I then give a personal perspective on the future of sustained observations. New measurement techniques promise exciting discoveries concerning the role of smaller scales and boundary processes in setting the large-scale ocean circulation and the ocean's role in climate. The challenges now facing the scientific community include sustaining critical observations in the case of funding system changes or shifts in government priorities. These long records will enable a determination of the role and response of the ocean to climate change.
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Affiliation(s)
- E Frajka-Williams
- University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
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24
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Reinthaler T, Salgado XAÁ, Alvarez M, van Aken HM, Herndl GJ. Impact of water mass mixing on the biogeochemistry and microbiology of the Northeast Atlantic Deep Water. GLOBAL BIOGEOCHEMICAL CYCLES 2013; 27:1151-1162. [PMID: 24683294 PMCID: PMC3966262 DOI: 10.1002/2013gb004634] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The extent to which water mass mixing contributes to the biological activity of the dark ocean is essentially unknown. Using a multiparameter water mass analysis, we examined the impact of water mass mixing on the nutrient distribution and microbial activity of the Northeast Atlantic Deep Water (NEADW) along an 8000 km long transect extending from 62°N to 5°S. Mixing of four water types (WT) and basin scale mineralization from the site where the WT where defined to the study area explained up to 95% of the variability in the distribution of inorganic nutrients and apparent oxygen utilization. Mixing-corrected average O2:N:P mineralization ratios of 127(±11):13.0(±0.7):1 in the core of the NEADW suggested preferential utilization of phosphorus compounds while dissolved organic carbon mineralization contributed a maximum of 20% to the oxygen demand of the NEADW. In conjunction with the calculated average mineralization ratios, our results indicate a major contribution of particulate organic matter to the biological activity in the NEADW. The variability in prokaryotic abundance, high nucleic acid containing cells, and prokaryotic heterotrophic production in the NEADW was explained by large scale (64-79%) and local mineralization processes (21-36%), consistent with the idea that deep-water prokaryotic communities are controlled by substrate supply. Overall, our results suggest a major impact of mixing on the distribution of inorganic nutrients and a weaker influence on the dissolved organic matter pool supporting prokaryotic activity in the NEADW.
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Affiliation(s)
- Thomas Reinthaler
- Department of Limnology and Oceanography, University of Vienna, Vienna, Austria ; Department of Marine Biology, University of Vienna, Vienna, Austria
| | | | - Marta Alvarez
- Instituto Español de Oceanografía (IEO), A Coruña, Spain
| | - Hendrik M van Aken
- Department of Physical Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), Den Burg, Netherlands
| | - Gerhard J Herndl
- Department of Limnology and Oceanography, University of Vienna, Vienna, Austria ; Department of Biological Oceanography, Royal Netherlands Institute for Sea Research (NIOZ), Den Burg, Netherlands
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25
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McClure MM, Alexander M, Borggaard D, Boughton D, Crozier L, Griffis R, Jorgensen JC, Lindley ST, Nye J, Rowland MJ, Seney EE, Snover A, Toole C, VAN Houtan K. Incorporating climate science in applications of the US endangered species act for aquatic species. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2013; 27:1222-1233. [PMID: 24299088 DOI: 10.1111/cobi.12166] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 05/27/2013] [Indexed: 06/02/2023]
Abstract
Aquatic species are threatened by climate change but have received comparatively less attention than terrestrial species. We gleaned key strategies for scientists and managers seeking to address climate change in aquatic conservation planning from the literature and existing knowledge. We address 3 categories of conservation effort that rely on scientific analysis and have particular application under the U.S. Endangered Species Act (ESA): assessment of overall risk to a species; long-term recovery planning; and evaluation of effects of specific actions or perturbations. Fewer data are available for aquatic species to support these analyses, and climate effects on aquatic systems are poorly characterized. Thus, we recommend scientists conducting analyses supporting ESA decisions develop a conceptual model that links climate, habitat, ecosystem, and species response to changing conditions and use this model to organize analyses and future research. We recommend that current climate conditions are not appropriate for projections used in ESA analyses and that long-term projections of climate-change effects provide temporal context as a species-wide assessment provides spatial context. In these projections, climate change should not be discounted solely because the magnitude of projected change at a particular time is uncertain when directionality of climate change is clear. Identifying likely future habitat at the species scale will indicate key refuges and potential range shifts. However, the risks and benefits associated with errors in modeling future habitat are not equivalent. The ESA offers mechanisms for increasing the overall resilience and resistance of species to climate changes, including establishing recovery goals requiring increased genetic and phenotypic diversity, specifying critical habitat in areas not currently occupied but likely to become important, and using adaptive management. Incorporación de las Ciencias Climáticas en las Aplicaciones del Acta Estadunidense de Especies en Peligro para Especies Acuáticas.
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Affiliation(s)
- Michelle M McClure
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northwest Fisheries Science Center, 2725 Montlake Boulevard, East, Seattle, WA, 98112, U.S.A..
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Hinzman LD, Deal CJ, McGuire AD, Mernild SH, Polyakov IV, Walsh JE. Trajectory of the Arctic as an integrated system. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2013; 23:1837-68. [PMID: 24555312 DOI: 10.1890/11-1498.1] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Although much remains to be learned about the Arctic and its component processes, many of the most urgent scientific, engineering, and social questions can only be approached through a broader system perspective. Here, we address interactions between components of the Arctic system and assess feedbacks and the extent to which feedbacks (1) are now underway in the Arctic and (2) will shape the future trajectory of the Arctic system. We examine interdependent connections among atmospheric processes, oceanic processes, sea-ice dynamics, marine and terrestrial ecosystems, land surface stocks of carbon and water, glaciers and ice caps, and the Greenland ice sheet. Our emphasis on the interactions between components, both historical and anticipated, is targeted on the feedbacks, pathways, and processes that link these different components of the Arctic system. We present evidence that the physical components of the Arctic climate system are currently in extreme states, and that there is no indication that the system will deviate from this anomalous trajectory in the foreseeable future. The feedback for which the evidence of ongoing changes is most compelling is the surface albedo-temperature feedback, which is amplifying temperature changes over land (primarily in spring) and ocean (primarily in autumn-winter). Other feedbacks likely to emerge are those in which key processes include surface fluxes of trace gases, changes in the distribution of vegetation, changes in surface soil moisture, changes in atmospheric water vapor arising from higher temperatures and greater areas of open ocean, impacts of Arctic freshwater fluxes on the meridional overturning circulation of the ocean, and changes in Arctic clouds resulting from changes in water vapor content.
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Affiliation(s)
- Larry D Hinzman
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA.
| | - Clara J Deal
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
| | - A David McGuire
- U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
| | | | - Igor V Polyakov
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
| | - John E Walsh
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA
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Baumann H, Doherty O. Decadal Changes in the World's Coastal Latitudinal Temperature Gradients. PLoS One 2013; 8:e67596. [PMID: 23825672 PMCID: PMC3689001 DOI: 10.1371/journal.pone.0067596] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 05/20/2013] [Indexed: 11/18/2022] Open
Abstract
Most of the world's living marine resources inhabit coastal environments, where average thermal conditions change predictably with latitude. These coastal latitudinal temperature gradients (CLTG) coincide with important ecological clines,e.g., in marine species diversity or adaptive genetic variations, but how tightly thermal and ecological gradients are linked remains unclear. A first step is to consistently characterize the world's CLTGs. We extracted coastal cells from a global 1°×1° dataset of weekly sea surface temperatures (SST, 1982–2012) to quantify spatial and temporal variability of the world's 11 major CLTGs. Gradient strength, i.e., the slope of the linear mean-SST/latitude relationship, varied 3-fold between the steepest (North-American Atlantic and Asian Pacific gradients: −0.91°C and −0.68°C lat−1, respectively) and weakest CLTGs (African Indian Ocean and the South- and North-American Pacific gradients: −0.28, −0.29, −0.32°C lat−1, respectively). Analyzing CLTG strength by year revealed that seven gradients have weakened by 3–10% over the past three decades due to increased warming at high compared to low latitudes. Almost the entire South-American Pacific gradient (6–47°S), however, has considerably cooled over the study period (−0.3 to −1.7°C, 31 years), and the substantial weakening of the North-American Atlantic gradient (−10%) was due to warming at high latitudes (42–60°N, +0.8 to +1.6°C,31 years) and significant mid-latitude cooling (Florida to Cape Hatteras 26–35°N, −0.5 to −2.2°C, 31 years). Average SST trends rarely resulted from uniform shifts throughout the year; instead individual seasonal warming or cooling patterns elicited the observed changes in annual means. This is consistent with our finding of increased seasonality (i.e., summer-winter SST amplitude) in three quarters of all coastal cells (331 of 433). Our study highlights the regionally variable footprint of global climate change, while emphasizing ecological implications of changing CLTGs, which are likely driving observed spatial and temporal clines in coastal marine life.
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Affiliation(s)
- Hannes Baumann
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, United States of America
- * E-mail:
| | - Owen Doherty
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
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Assessing the meridional atmosphere and ocean energy transport in a varying climate. CHINESE SCIENCE BULLETIN-CHINESE 2013. [DOI: 10.1007/s11434-013-5665-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Baum SD, Maher TM, Haqq-Misra J. Double catastrophe: intermittent stratospheric geoengineering induced by societal collapse. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s10669-012-9429-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Robinson LF, Siddall M. Palaeoceanography: motivations and challenges for the future. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2012; 370:5540-5566. [PMID: 23129712 DOI: 10.1098/rsta.2012.0396] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The ocean interacts with the atmosphere, biosphere and cryosphere in a complex way, modulating climate through the storage and transport of heat, nutrients and carbon. As such, it is important that we understand the ways in which the ocean behaves and the factors that can lead to change. In order to gain this understanding, we need to look back into the past, on time scales from recent decadal-scale change, through the abrupt changes of the Pleistocene and back to times when the Earth's climate was significantly different than the Holocene. A key challenge facing the field of palaeoceanography is to combine data and modelling in a common framework. Coupling palaeo-data and models should improve our knowledge of how the Earth works, and perhaps of more direct societal relevance, might enable us to provide better predictive capabilities in climate modelling. In this discussion paper, we examine the motivations, past successes and challenges facing palaeoceanographic studies. We then suggest a number of areas and approaches that we believe will allow palaeoceanography to continue to provide new insights into processes that affect future climate change.
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Seymour JR, Doblin MA, Jeffries TC, Brown MV, Newton K, Ralph PJ, Baird M, Mitchell JG. Contrasting microbial assemblages in adjacent water masses associated with the East Australian Current. ENVIRONMENTAL MICROBIOLOGY REPORTS 2012; 4:548-555. [PMID: 23760900 DOI: 10.1111/j.1758-2229.2012.00362.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Accepted: 05/30/2012] [Indexed: 06/02/2023]
Abstract
Different oceanographic provinces host discrete microbial assemblages that are adapted to local physicochemical conditions. We sequenced and compared the metagenomes of two microbial communities inhabiting adjacent water masses in the Tasman Sea, where the recent strengthening of the East Australian Current (EAC) has altered the ecology of coastal environments. Despite the comparable latitude of the samples, significant phylogenetic differences were apparent, including shifts in the relative frequency of matches to Cyanobacteria, Crenarchaeota and Euryarchaeota. Fine-scale variability in the structure of SAR11, Prochlorococcus and Synechococcus populations, with more matches to 'warm-water' ecotypes observed in the EAC, indicates the EAC may drive an intrusion of tropical microbes into temperate regions of the Tasman Sea. Furthermore, significant shifts in the relative importance of 17 metabolic categories indicate that the EAC prokaryotic community has different physiological properties than surrounding waters.
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Affiliation(s)
- Justin R Seymour
- Plant Functional Biology & Climate Change Cluster, University of Technology, PO Box 123, Broadway, Sydney, NSW, 2007, Australia
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Surface changes in the North Atlantic meridional overturning circulation during the last millennium. Nat Commun 2012; 3:899. [PMID: 22692542 PMCID: PMC3621426 DOI: 10.1038/ncomms1901] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 05/10/2012] [Indexed: 11/28/2022] Open
Abstract
Despite numerous investigations, the dynamical origins of the Medieval Climate Anomaly and the Little Ice Age remain uncertain. A major unresolved issue relating to internal climate dynamics is the mode and tempo of Atlantic meridional overturning circulation variability, and the significance of decadal-to-centennial scale changes in Atlantic meridional overturning circulation strength in regulating the climate of the last millennium. Here we use the time-constrained high-resolution local radiocarbon reservoir age offset derived from an absolutely dated annually resolved shell chronology spanning the past 1,350 years, to reconstruct changes in surface ocean circulation and climate. The water mass tracer data presented here from the North Icelandic shelf, combined with previously published data from the Arctic and subtropical Atlantic, show that surface Atlantic meridional overturning circulation dynamics likely amplified the relatively warm conditions during the Medieval Climate Anomaly and the relatively cool conditions during the Little Ice Age within the North Atlantic sector. Palaeoclimate proxies, such as shells, record past ocean changes. A radiocarbon study based on a shell chronology from the Icelandic shelf is used to track changes in ocean circulation and climate for the past 1,350 years, suggesting a declining influence of North Atlantic surface waters on the Icelandic shelf over the last millennium.
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Abstract
The global overturning of ocean waters involves the equatorward transport of cold, deep waters and the poleward transport of warm, near-surface waters. Such movement creates a net poleward transport of heat that, in partnership with the atmosphere, establishes the global and regional climates. Although oceanographers have long assumed that a reduction in deep water formation at high latitudes in the North Atlantic translates into a slowing of the ocean's overturning and hence in Earth's climate, observational and modeling studies over the past decade have called this assumed linkage into question. The observational basis for linking water mass formation with the ocean's meridional overturning is reviewed herein. Understanding this linkage is crucial to efforts aimed at predicting the consequences of the warming and freshening of high-latitude surface waters to the climate system.
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Affiliation(s)
- M Susan Lozier
- Division of Earth and Ocean Sciences, Nicholas School of the Environment, Duke University, Durham, North Carolina 27708, USA.
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Frajka-Williams E, Cunningham SA, Bryden H, King BA. Variability of Antarctic Bottom Water at 24.5°N in the Atlantic. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jc007168] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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36
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Danovaro R, Corinaldesi C, Dell'Anno A, Fuhrman JA, Middelburg JJ, Noble RT, Suttle CA. Marine viruses and global climate change. FEMS Microbiol Rev 2011; 35:993-1034. [DOI: 10.1111/j.1574-6976.2010.00258.x] [Citation(s) in RCA: 245] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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Zhang D, Msadek R, McPhaden MJ, Delworth T. Multidecadal variability of the North Brazil Current and its connection to the Atlantic meridional overturning circulation. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jc006812] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Model evidence for climatic impact of thermohaline circulation on China at the century scale. ACTA ACUST UNITED AC 2010. [DOI: 10.1007/s11434-010-4089-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Bianchi TS, DiMarco SF, Cowan JH, Hetland RD, Chapman P, Day JW, Allison MA. The science of hypoxia in the Northern Gulf of Mexico: a review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2010; 408:1471-1484. [PMID: 20092873 DOI: 10.1016/j.scitotenv.2009.11.047] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Revised: 11/19/2009] [Accepted: 11/21/2009] [Indexed: 05/28/2023]
Abstract
The Mississippi River is one of the world's 10 largest rivers, with average freshwater discharge into the northern Gulf of Mexico (GOM) of 380km(3) year(-1). In the northern GOM, anthropogenic nitrogen is primarily derived from agricultural fertilizer and delivered via the Mississippi River. The general consensus is that hypoxia in the northern Gulf of Mexico is caused primarily by algal production stimulated by excess nitrogen delivered from the Mississippi-Atchafalaya River Basin and seasonal vertical stratification of incoming stream flow and Gulf waters, which restricts replenishment of oxygen from the atmosphere. In this paper, we review the controversial aspects of the largely nutrient-centric view of the hypoxic region, and introduce the role of non-riverine organic matter inputs as other oxygen-consuming mechanisms. Similarly, we discuss non-nutrient physically-controlled impacts of freshwater stratification as an alternative mechanism for controlling in part, the seasonality of hypoxia. We then explore why hypoxia in this dynamic river-dominated margin (RiOMar) is not comparable to many of the other traditional estuarine systems (e.g., Chesapeake Bay, Baltic Sea, and Long Island Sound). The presence of mobile muds and the proximity of the Mississippi Canyon are discussed as possible reasons for the amelioration of hypoxia (e.g., healthy fisheries) in this region. The most recent prediction of hypoxia area for 2009, using the current nutrient-centric models, failed due to the limited scope of these simple models and the complexity of this system. Predictive models should not be the main driver for management decisions. We postulate that a better management plan for this region can only be reached through a more comprehensive understanding of this RiOMar system-not just more information on river fluxes (e.g., nutrients) and coastal hypoxia monitoring programs.
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Affiliation(s)
- T S Bianchi
- Department of Oceanography, Texas A&M University, College Station, Texas 77843-3146, USA.
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40
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Zheng Y, Giese BS. Ocean heat transport in Simple Ocean Data Assimilation: Structure and mechanisms. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jc005190] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Graham CT, Harrod C. Implications of climate change for the fishes of the British Isles. JOURNAL OF FISH BIOLOGY 2009; 74:1143-1205. [PMID: 20735625 DOI: 10.1111/j.1095-8649.2009.02180.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recent climatic change has been recorded across the globe. Although environmental change is a characteristic feature of life on Earth and has played a major role in the evolution and global distribution of biodiversity, predicted future rates of climatic change, especially in temperature, are such that they will exceed any that has occurred over recent geological time. Climate change is considered as a key threat to biodiversity and to the structure and function of ecosystems that may already be subject to significant anthropogenic stress. The current understanding of climate change and its likely consequences for the fishes of Britain and Ireland and the surrounding seas are reviewed through a series of case studies detailing the likely response of several marine, diadromous and freshwater fishes to climate change. Changes in climate, and in particular, temperature have and will continue to affect fish at all levels of biological organization: cellular, individual, population, species, community and ecosystem, influencing physiological and ecological processes in a number of direct, indirect and complex ways. The response of fishes and of other aquatic taxa will vary according to their tolerances and life stage and are complex and difficult to predict. Fishes may respond directly to climate-change-related shifts in environmental processes or indirectly to other influences, such as community-level interactions with other taxa. However, the ability to adapt to the predicted changes in climate will vary between species and between habitats and there will be winners and losers. In marine habitats, recent changes in fish community structure will continue as fishes shift their distributions relative to their temperature preferences. This may lead to the loss of some economically important cold-adapted species such as Gadus morhua and Clupea harengus from some areas around Britain and Ireland, and the establishment of some new, warm-adapted species. Increased temperatures are likely to favour cool-adapted (e.g. Perca fluviatilis) and warm-adapted freshwater fishes (e.g. roach Rutilus rutilus and other cyprinids) whose distribution and reproductive success may currently be constrained by temperature rather than by cold-adapted species (e.g. salmonids). Species that occur in Britain and Ireland that are at the edge of their distribution will be most affected, both negatively and positively. Populations of conservation importance (e.g.Salvelinus alpinus and Coregonus spp.) may decline irreversibly. However, changes in food-web dynamics and physiological adaptation, for example because of climate change, may obscure or alter predicted responses. The residual inertia in climate systems is such that even a complete cessation in emissions would still leave fishes exposed to continued climate change for at least half a century. Hence, regardless of the success or failure of programmes aimed at curbing climate change, major changes in fish communities can be expected over the next 50 years with a concomitant need to adapt management strategies accordingly.
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Affiliation(s)
- C T Graham
- Department of Zoology, Ecology and Plant Science, University College Cork, Ireland
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42
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Harding AMA, Egevang C, Walkusz W, Merkel F, Blanc S, Grémillet D. Estimating prey capture rates of a planktivorous seabird, the little auk (Alle alle), using diet, diving behaviour, and energy consumption. Polar Biol 2009. [DOI: 10.1007/s00300-009-0581-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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43
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Kouketsu S, Fukasawa M, Kaneko I, Kawano T, Uchida H, Doi T, Aoyama M, Murakami K. Changes in water properties and transports along 24°N in the North Pacific between 1985 and 2005. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jc004778] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Reid PC, Fischer AC, Lewis-Brown E, Meredith MP, Sparrow M, Andersson AJ, Antia A, Bates NR, Bathmann U, Beaugrand G, Brix H, Dye S, Edwards M, Furevik T, Gangstø R, Hátún H, Hopcroft RR, Kendall M, Kasten S, Keeling R, Le Quéré C, Mackenzie FT, Malin G, Mauritzen C, Olafsson J, Paull C, Rignot E, Shimada K, Vogt M, Wallace C, Wang Z, Washington R. Chapter 1. Impacts of the oceans on climate change. ADVANCES IN MARINE BIOLOGY 2009; 56:1-150. [PMID: 19895974 DOI: 10.1016/s0065-2881(09)56001-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The oceans play a key role in climate regulation especially in part buffering (neutralising) the effects of increasing levels of greenhouse gases in the atmosphere and rising global temperatures. This chapter examines how the regulatory processes performed by the oceans alter as a response to climate change and assesses the extent to which positive feedbacks from the ocean may exacerbate climate change. There is clear evidence for rapid change in the oceans. As the main heat store for the world there has been an accelerating change in sea temperatures over the last few decades, which has contributed to rising sea-level. The oceans are also the main store of carbon dioxide (CO2), and are estimated to have taken up approximately 40% of anthropogenic-sourced CO2 from the atmosphere since the beginning of the industrial revolution. A proportion of the carbon uptake is exported via the four ocean 'carbon pumps' (Solubility, Biological, Continental Shelf and Carbonate Counter) to the deep ocean reservoir. Increases in sea temperature and changing planktonic systems and ocean currents may lead to a reduction in the uptake of CO2 by the ocean; some evidence suggests a suppression of parts of the marine carbon sink is already underway. While the oceans have buffered climate change through the uptake of CO2 produced by fossil fuel burning this has already had an impact on ocean chemistry through ocean acidification and will continue to do so. Feedbacks to climate change from acidification may result from expected impacts on marine organisms (especially corals and calcareous plankton), ecosystems and biogeochemical cycles. The polar regions of the world are showing the most rapid responses to climate change. As a result of a strong ice-ocean influence, small changes in temperature, salinity and ice cover may trigger large and sudden changes in regional climate with potential downstream feedbacks to the climate of the rest of the world. A warming Arctic Ocean may lead to further releases of the potent greenhouse gas methane from hydrates and permafrost. The Southern Ocean plays a critical role in driving, modifying and regulating global climate change via the carbon cycle and through its impact on adjacent Antarctica. The Antarctic Peninsula has shown some of the most rapid rises in atmospheric and oceanic temperature in the world, with an associated retreat of the majority of glaciers. Parts of the West Antarctic ice sheet are deflating rapidly, very likely due to a change in the flux of oceanic heat to the undersides of the floating ice shelves. The final section on modelling feedbacks from the ocean to climate change identifies limitations and priorities for model development and associated observations. Considering the importance of the oceans to climate change and our limited understanding of climate-related ocean processes, our ability to measure the changes that are taking place are conspicuously inadequate. The chapter highlights the need for a comprehensive, adequately funded and globally extensive ocean observing system to be implemented and sustained as a high priority. Unless feedbacks from the oceans to climate change are adequately included in climate change models, it is possible that the mitigation actions needed to stabilise CO2 and limit temperature rise over the next century will be underestimated.
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Affiliation(s)
- Philip C Reid
- Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
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Lorenzo MN, Taboada JJ, Iglesias I, Álvarez I. The Role of Stochastic Forcing on the Behavior of Thermohaline Circulation. Ann N Y Acad Sci 2008; 1146:60-86. [DOI: 10.1196/annals.1446.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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46
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Biastoch A, Böning CW, Lutjeharms JRE. Agulhas leakage dynamics affects decadal variability in Atlantic overturning circulation. Nature 2008; 456:489-92. [DOI: 10.1038/nature07426] [Citation(s) in RCA: 223] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Accepted: 09/09/2008] [Indexed: 11/09/2022]
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47
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Bingham RJ, Hughes CW. Determining North Atlantic meridional transport variability from pressure on the western boundary: A model investigation. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jc004679] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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48
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Observed and modelled stability of overflow across the Greenland–Scotland ridge. Nature 2008; 455:519-22. [DOI: 10.1038/nature07302] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 07/31/2008] [Indexed: 11/08/2022]
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49
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Marsh R, Josey SA, de Cuevas BA, Redbourn LJ, Quartly GD. Mechanisms for recent warming of the North Atlantic: Insights gained with an eddy-permitting model. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2007jc004096] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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Affiliation(s)
- Ralph F. Keeling
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
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