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Yamazaki K, Aoki S, Katsumata K, Hirano D, Nakayama Y. Multidecadal poleward shift of the southern boundary of the Antarctic Circumpolar Current off East Antarctica. SCIENCE ADVANCES 2021; 7:7/24/eabf8755. [PMID: 34117060 PMCID: PMC8195479 DOI: 10.1126/sciadv.abf8755] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/28/2021] [Indexed: 06/12/2023]
Abstract
The southern boundary (SB) of the Antarctic Circumpolar Current, the southernmost extent of the upper overturning circulation, regulates the Antarctic thermal conditions. The SB's behavior remains unconstrained because it does not have a clear surface signature. Revisited hydrographic data from off East Antarctica indicate full-depth warming from 1996 to 2019, concurrent with an extensive poleward shift of the SB subsurface isotherms (>50 km), which is most prominent at 120°E off the Sabrina Coast. The SB shift is attributable to enhanced upper overturning circulation and a depth-independent frontal shift, generally accounting for 30 and 70%, respectively. Thirty years of oceanographic data corroborate the overall and localized poleward shifts that are likely controlled by continental slope topography. Numerical experiments successfully reproduce this locality and demonstrate its sensitivity to mesoscale processes and wind forcing. The poleward SB shift under intensified westerlies potentially induces multidecadal warming of Antarctic shelf water.
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Affiliation(s)
- Kaihe Yamazaki
- Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan.
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Shigeru Aoki
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
| | - Katsuro Katsumata
- Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
| | - Daisuke Hirano
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
- Arctic Research Center, Hokkaido University, Sapporo, Japan
| | - Yoshihiro Nakayama
- Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
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Rintoul SR. The global influence of localized dynamics in the Southern Ocean. Nature 2018; 558:209-218. [DOI: 10.1038/s41586-018-0182-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/27/2018] [Indexed: 11/09/2022]
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Naveira Garabato AC, MacGilchrist GA, Brown PJ, Evans DG, Meijers AJS, Zika JD. High-latitude ocean ventilation and its role in Earth's climate transitions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 376:rsta.2017.0324. [PMID: 28784714 DOI: 10.1098/rsta.2017.0324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/23/2018] [Indexed: 05/13/2023]
Abstract
The processes regulating ocean ventilation at high latitudes are re-examined based on a range of observations spanning all scales of ocean circulation, from the centimetre scales of turbulence to the basin scales of gyres. It is argued that high-latitude ocean ventilation is controlled by mechanisms that differ in fundamental ways from those that set the overturning circulation. This is contrary to the assumption of broad equivalence between the two that is commonly adopted in interpreting the role of the high-latitude oceans in Earth's climate transitions. Illustrations of how recognizing this distinction may change our view of the ocean's role in the climate system are offered.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.
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Affiliation(s)
| | | | | | - D Gwyn Evans
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | | | - Jan D Zika
- School of Mathematics and Statistics, University of New South Wales, Sydney, Australia
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Naveira Garabato AC, MacGilchrist GA, Brown PJ, Evans DG, Meijers AJS, Zika JD. High-latitude ocean ventilation and its role in Earth's climate transitions. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2017; 375:rsta.2016.0324. [PMID: 28784714 PMCID: PMC5559419 DOI: 10.1098/rsta.2016.0324] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/05/2017] [Indexed: 05/13/2023]
Abstract
The processes regulating ocean ventilation at high latitudes are re-examined based on a range of observations spanning all scales of ocean circulation, from the centimetre scales of turbulence to the basin scales of gyres. It is argued that high-latitude ocean ventilation is controlled by mechanisms that differ in fundamental ways from those that set the overturning circulation. This is contrary to the assumption of broad equivalence between the two that is commonly adopted in interpreting the role of the high-latitude oceans in Earth's climate transitions. Illustrations of how recognizing this distinction may change our view of the ocean's role in the climate system are offered.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.
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Affiliation(s)
| | | | | | - D Gwyn Evans
- Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK
| | | | - Jan D Zika
- School of Mathematics and Statistics, University of New South Wales, Sydney, Australia
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Young EF, Belchier M, Hauser L, Horsburgh GJ, Meredith MP, Murphy EJ, Pascoal S, Rock J, Tysklind N, Carvalho GR. Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species. Evol Appl 2015; 8:486-509. [PMID: 26029262 PMCID: PMC4430772 DOI: 10.1111/eva.12259] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 02/27/2015] [Indexed: 01/27/2023] Open
Abstract
Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a 'seascape genetics' approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.
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Affiliation(s)
| | | | - Lorenz Hauser
- School of Aquatic and Fishery Sciences, University of Washington Seattle, WA, USA
| | - Gavin J Horsburgh
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK
| | | | | | - Sonia Pascoal
- School of Biological Sciences, Bangor University Bangor, Gwynedd, UK
| | - Jennifer Rock
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield Sheffield, UK ; School of Biological Sciences, Bangor University Bangor, Gwynedd, UK ; Present address: Department of Zoology, University of Otago Dunedin, 9054, New Zealand
| | - Niklas Tysklind
- School of Biological Sciences, Bangor University Bangor, Gwynedd, UK ; Present address: Campus Agronomique BP 709-97387, Kourou Cedex, France
| | - Gary R Carvalho
- School of Biological Sciences, Bangor University Bangor, Gwynedd, UK
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Constable AJ, Melbourne-Thomas J, Corney SP, Arrigo KR, Barbraud C, Barnes DKA, Bindoff NL, Boyd PW, Brandt A, Costa DP, Davidson AT, Ducklow HW, Emmerson L, Fukuchi M, Gutt J, Hindell MA, Hofmann EE, Hosie GW, Iida T, Jacob S, Johnston NM, Kawaguchi S, Kokubun N, Koubbi P, Lea MA, Makhado A, Massom RA, Meiners K, Meredith MP, Murphy EJ, Nicol S, Reid K, Richerson K, Riddle MJ, Rintoul SR, Smith WO, Southwell C, Stark JS, Sumner M, Swadling KM, Takahashi KT, Trathan PN, Welsford DC, Weimerskirch H, Westwood KJ, Wienecke BC, Wolf-Gladrow D, Wright SW, Xavier JC, Ziegler P. Climate change and Southern Ocean ecosystems I: how changes in physical habitats directly affect marine biota. GLOBAL CHANGE BIOLOGY 2014; 20:3004-25. [PMID: 24802817 DOI: 10.1111/gcb.12623] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 03/05/2014] [Indexed: 05/06/2023]
Abstract
Antarctic and Southern Ocean (ASO) marine ecosystems have been changing for at least the last 30 years, including in response to increasing ocean temperatures and changes in the extent and seasonality of sea ice; the magnitude and direction of these changes differ between regions around Antarctica that could see populations of the same species changing differently in different regions. This article reviews current and expected changes in ASO physical habitats in response to climate change. It then reviews how these changes may impact the autecology of marine biota of this polar region: microbes, zooplankton, salps, Antarctic krill, fish, cephalopods, marine mammals, seabirds, and benthos. The general prognosis for ASO marine habitats is for an overall warming and freshening, strengthening of westerly winds, with a potential pole-ward movement of those winds and the frontal systems, and an increase in ocean eddy activity. Many habitat parameters will have regionally specific changes, particularly relating to sea ice characteristics and seasonal dynamics. Lower trophic levels are expected to move south as the ocean conditions in which they are currently found move pole-ward. For Antarctic krill and finfish, the latitudinal breadth of their range will depend on their tolerance of warming oceans and changes to productivity. Ocean acidification is a concern not only for calcifying organisms but also for crustaceans such as Antarctic krill; it is also likely to be the most important change in benthic habitats over the coming century. For marine mammals and birds, the expected changes primarily relate to their flexibility in moving to alternative locations for food and the energetic cost of longer or more complex foraging trips for those that are bound to breeding colonies. Few species are sufficiently well studied to make comprehensive species-specific vulnerability assessments possible. Priorities for future work are discussed.
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Affiliation(s)
- Andrew J Constable
- Australian Antarctic Division, Channel Highway, Kingston, Tasmania, 7050, Australia; Antarctic Climate and Ecosystems Cooperative Research Centre, Private Bag 80, Hobart, Tasmania, 7001, Australia
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Meijers AJS. The Southern Ocean in the Coupled Model Intercomparison Project phase 5. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2014; 372:20130296. [PMID: 24891395 PMCID: PMC4032513 DOI: 10.1098/rsta.2013.0296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The Southern Ocean is an important part of the global climate system, but its complex coupled nature makes both its present state and its response to projected future climate forcing difficult to model. Clear trends in wind, sea-ice extent and ocean properties emerged from multi-model intercomparison in the Coupled Model Intercomparison Project phase 3 (CMIP3). Here, we review recent analyses of the historical and projected wind, sea ice, circulation and bulk properties of the Southern Ocean in the updated Coupled Model Intercomparison Project phase 5 (CMIP5) ensemble. Improvements to the models include higher resolutions, more complex and better-tuned parametrizations of ocean mixing, and improved biogeochemical cycles and atmospheric chemistry. CMIP5 largely reproduces the findings of CMIP3, but with smaller inter-model spreads and biases. By the end of the twenty-first century, mid-latitude wind stresses increase and shift polewards. All water masses warm, and intermediate waters freshen, while bottom waters increase in salinity. Surface mixed layers shallow, warm and freshen, whereas sea ice decreases. The upper overturning circulation intensifies, whereas bottom water formation is reduced. Significant disagreement exists between models for the response of the Antarctic Circumpolar Current strength, for reasons that are as yet unclear.
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Affiliation(s)
- A J S Meijers
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK
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Meijers AJS, Shuckburgh E, Bruneau N, Sallee JB, Bracegirdle TJ, Wang Z. Representation of the Antarctic Circumpolar Current in the CMIP5 climate models and future changes under warming scenarios. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012jc008412] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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