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Han X, Stewart AL, Chen D, Janout M, Liu X, Wang Z, Gordon AL. Circum-Antarctic bottom water formation mediated by tides and topographic waves. Nat Commun 2024; 15:2049. [PMID: 38448416 PMCID: PMC10918180 DOI: 10.1038/s41467-024-46086-1] [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: 08/29/2023] [Accepted: 02/14/2024] [Indexed: 03/08/2024] Open
Abstract
The downslope plumes of dense shelf water (DSW) are critical for the formation of Antarctic Bottom Water (AABW), and thus to the exchange of heat and carbon between surface and abyssal ocean. Previous studies have shown that tides and overflow-forced topographic Rossby waves (TRWs) may have strong impact on the downslope transport of DSW, but it remains unclear how the combined action of these two processes influence the descent processes of DSW, and of the resulting AABW properties. Here, with a synthesis of historical in situ observations and a set of numerical model experiments, we show that tides and TRWs play comparable roles in AABW formation: they both act to accelerate DSW descent to the abyss, leading to the formation of colder and denser AABW. Yet, tides have little impact on AABW formation unless the continental slope is steep enough to suppress TRW generation. We further characterize the dynamical regimes of dense overflows around the entire Antarctic continent based on the relative importance of TRWs versus tides. These findings highlight the pervasive role of high-frequency processes, which are not well represented in the present climate models, in the formation of AABW, and thus in the global overturning circulation.
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Affiliation(s)
- Xianxian Han
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, China
| | - Andrew L Stewart
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, CA, USA
| | - Dake Chen
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China.
- School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai, China.
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China.
| | - Markus Janout
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Xiaohui Liu
- State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Zhaomin Wang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
| | - Arnold L Gordon
- Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, USA
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Age distribution of Antarctic Bottom Water off Cape Darnley, East Antarctica, estimated using chlorofluorocarbon and sulfur hexafluoride. Sci Rep 2022; 12:8462. [PMID: 35589760 PMCID: PMC9120186 DOI: 10.1038/s41598-022-12109-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 05/03/2022] [Indexed: 12/04/2022] Open
Abstract
Chlorofluorocarbon (CFC) and sulfur hexafluoride (SF6) were used to investigate the timescale of Antarctic Bottom Water (AABW) that spreads off Cape Darnley (CD) in East Antarctica. The age of the AABW was estimated based on the observed SF6/CFC-12 ratio while taking into account tracer dilution by Lower Circumpolar Deep Water. Along the western canyons off CD and the ~ 3000 to 3500 m isobaths, the bottom water age was < 5 years, reflecting the spread of newly formed CD Bottom Water. Higher ages of ~ 8 years obtained for areas east of CD and > 20 years in the northwestern offshore region indicate inflows of AABW through the Princess Elizabeth Trough and Weddell Sea Deep Water, respectively. This study determined the age distribution in the region off CD, where three different types of AABW spread.
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Corliss BA, Delalio LJ, Stevenson Keller TC, Keller AS, Keller DA, Corliss BH, Beers JM, Peirce SM, Isakson BE. Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver. Front Physiol 2019; 10:1389. [PMID: 31780954 PMCID: PMC6861181 DOI: 10.3389/fphys.2019.01389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/24/2019] [Indexed: 12/16/2022] Open
Abstract
Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body's iron, which is known to be a limiting nutrient in marine ecosystems. Since lower RBC levels also lead to reduced iron requirements, we hypothesize that low iron availability was an additional evolutionary driver of Antarctic fish speciation. Antarctic Icefish of the family Channichthyidae are known to have an extreme alteration of iron metabolism due to loss of RBCs and two iron-binding proteins, hemoglobin and myoglobin. Loss of hemoglobin is considered a maladaptive trait allowed by relaxation of predator selection since extreme adaptations are required to compensate for the loss of oxygen-carrying capacity. However, iron dependency minimization may have driven hemoglobin loss instead of a random evolutionary event. Given the variety of functions that hemoglobin serves in the endothelium, we suspected the protein corresponding to the 3' truncated Hbα fragment (Hbα-3'f) that was not genetically excluded by icefish may still be expressed as a protein. Using whole mount confocal microscopy, we show that Hbα-3'f is expressed in the vascular endothelium of icefish retina, suggesting this Hbα fragment may still serve an important role in the endothelium. These observations support a novel hypothesis that iron minimization could have influenced icefish speciation with the loss of the iron-binding portion of Hbα in Hbα-3'f, as well as hemoglobin β and myoglobin.
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Affiliation(s)
- Bruce A Corliss
- Biomedical Engineering Department, University of Virginia, Charlottesville, VA, United States
| | - Leon J Delalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States
| | | | - Bruce H Corliss
- Graduate School of Oceanography, University of Rhode Island, Kingston, RI, United States
| | - Jody M Beers
- Department of Biology, College of Charleston, Charleston, SC, United States
| | - Shayn M Peirce
- Biomedical Engineering Department, University of Virginia, Charlottesville, VA, United States
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, United States
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Purkey SG, Smethie WM, Gebbie G, Gordon AL, Sonnerup RE, Warner MJ, Bullister JL. A Synoptic View of the Ventilation and Circulation of Antarctic Bottom Water from Chlorofluorocarbons and Natural Tracers. ANNUAL REVIEW OF MARINE SCIENCE 2018; 10:503-527. [PMID: 28877009 DOI: 10.1146/annurev-marine-121916-063414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Antarctic Bottom Water (AABW) is the coldest, densest, most prolific water mass in the global ocean. AABW forms at several distinct regions along the Antarctic coast and feeds into the bottom limb of the meridional overturning circulation, filling most of the global deep ocean. AABW has warmed, freshened, and declined in volume around the globe in recent decades, which has implications for the global heat and sea level rise budgets. Over the past three decades, the use of tracers, especially time-varying tracers such as chlorofluorocarbons, has been essential to our understanding of the formation, circulation, and variability of AABW. Here, we review three decades of temperature, salinity, and tracer data and analysis that have led to our current knowledge of AABW and how the southern component of deep-ocean ventilation is changing with time.
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Affiliation(s)
- Sarah G Purkey
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California 92093, USA;
| | - William M Smethie
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA; ,
| | - Geoffrey Gebbie
- Department of Physical Oceanography, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA;
| | - Arnold L Gordon
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, USA; ,
| | - Rolf E Sonnerup
- Joint Institute for the Study of the Atmosphere and Ocean, University of Washington, Seattle, Washington 98195, USA;
- Pacific Marine and Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115, USA;
| | - Mark J Warner
- School of Oceanography, University of Washington, Seattle, Washington 98195, USA;
| | - John L Bullister
- Pacific Marine and Environmental Laboratory, National Oceanic and Atmospheric Administration, Seattle, Washington 98115, USA;
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Oellermann M, Lieb B, Pörtner HO, Semmens JM, Mark FC. Blue blood on ice: modulated blood oxygen transport facilitates cold compensation and eurythermy in an Antarctic octopod. Front Zool 2015; 12:6. [PMID: 25897316 PMCID: PMC4403823 DOI: 10.1186/s12983-015-0097-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 02/16/2015] [Indexed: 11/30/2022] Open
Abstract
INTRODUCTION The Antarctic Ocean hosts a rich and diverse fauna despite inhospitable temperatures close to freezing, which require specialist adaptations to sustain animal activity and various underlying body functions. While oxygen transport has been suggested to be key in setting thermal tolerance in warmer climates, this constraint is relaxed in Antarctic fishes and crustaceans, due to high levels of dissolved oxygen. Less is known about how other Antarctic ectotherms cope with temperatures near zero, particularly the more active invertebrates like the abundant octopods. A continued reliance on the highly specialised blood oxygen transport system of cephalopods may concur with functional constraints at cold temperatures. We therefore analysed the octopod's central oxygen transport component, the blue blood pigment haemocyanin, to unravel strategies that sustain oxygen supply at cold temperatures. RESULTS To identify adaptive compensation of blood oxygen transport in octopods from different climatic regions, we compared haemocyanin oxygen binding properties, oxygen carrying capacities as well as haemolymph protein and ion composition between the Antarctic octopod Pareledone charcoti, the South-east Australian Octopus pallidus and the Mediterranean Eledone moschata. In the Antarctic Pareledone charcoti at 0°C, oxygen unloading by haemocyanin was poor but supported by high levels of dissolved oxygen. However, lower oxygen affinity and higher oxygen carrying capacity compared to warm water octopods, still enabled significant contribution of haemocyanin to oxygen transport at 0°C. At warmer temperatures, haemocyanin of Pareledone charcoti releases most of the bound oxygen, supporting oxygen supply at 10°C. In warm water octopods, increasing oxygen affinities reduce the ability to release oxygen from haemocyanin at colder temperatures. Though, unlike Eledone moschata, Octopus pallidus attenuated this increase below 15°C. CONCLUSIONS Adjustments of haemocyanin physiological function and haemocyanin concentrations but also high dissolved oxygen concentrations support oxygen supply in the Antarctic octopus Pareledone charcoti at near freezing temperatures. Increased oxygen supply by haemocyanin at warmer temperatures supports extended warm tolerance and thus eurythermy of Pareledone charcoti. Limited haemocyanin function towards colder temperatures in Antarctic and warm water octopods highlights the general role of haemocyanin oxygen transport in constraining cold tolerance in octopods.
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Affiliation(s)
- Michael Oellermann
- />Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Bernhard Lieb
- />Institute of Zoology, Johannes Gutenberg-Universität, Müllerweg 6, 55099 Mainz, Germany
| | - Hans-O Pörtner
- />Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Jayson M Semmens
- />Fisheries, Aquaculture and Coasts Centre, Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania 7001 Australia
| | - Felix C Mark
- />Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
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Goldberg DN, Little CM, Sergienko OV, Gnanadesikan A, Hallberg R, Oppenheimer M. Investigation of land ice-ocean interaction with a fully coupled ice-ocean model: 1. Model description and behavior. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jf002246] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Broecker WS, Peacock SL, Walker S, Weiss R, Fahrbach E, Schroeder M, Mikolajewicz U, Heinze C, Key R, Peng TH, Rubin S. How much deep water is formed in the Southern Ocean? ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98jc00248] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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