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Li T, Robinson LF, MacGilchrist GA, Chen T, Stewart JA, Burke A, Wang M, Li G, Chen J, Rae JWB. Enhanced subglacial discharge from Antarctica during meltwater pulse 1A. Nat Commun 2023; 14:7327. [PMID: 37957152 PMCID: PMC10643554 DOI: 10.1038/s41467-023-42974-0] [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: 06/07/2023] [Accepted: 10/27/2023] [Indexed: 11/15/2023] Open
Abstract
Subglacial discharge from the Antarctic Ice Sheet (AIS) likely played a crucial role in the loss of the ice sheet and the subsequent rise in sea level during the last deglaciation. However, no direct proxy is currently available to document subglacial discharge from the AIS, which leaves significant gaps in our understanding of the complex interactions between subglacial discharge and ice-sheet stability. Here we present deep-sea coral 234U/238U records from the Drake Passage in the Southern Ocean to track subglacial discharge from the AIS. Our findings reveal distinctively higher seawater 234U/238U values from 15,400 to 14,000 years ago, corresponding to the period of the highest iceberg-rafted debris flux and the occurrence of the meltwater pulse 1A event. This correlation suggests a causal link between enhanced subglacial discharge, synchronous retreat of the AIS, and the rapid rise in sea levels. The enhanced subglacial discharge and subsequent AIS retreat appear to have been preconditioned by a stronger and warmer Circumpolar Deep Water, thus underscoring the critical role of oceanic heat in driving major ice-sheet retreat.
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Affiliation(s)
- Tao Li
- State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China.
- School of Earth Sciences, University of Bristol, Bristol, UK.
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing, China.
| | - Laura F Robinson
- School of Earth Sciences, University of Bristol, Bristol, UK
- Department of Environment and Geography, University of York, York, UK
| | - Graeme A MacGilchrist
- Program in Atmospheric and Oceanic Science, Princeton University, Princeton, NJ, USA
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - Tianyu Chen
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing, China
| | | | - Andrea Burke
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
| | - Maoyu Wang
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing, China
| | - Gaojun Li
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing, China
| | - Jun Chen
- Department of Earth and Planetary Sciences, Nanjing University, Nanjing, China
| | - James W B Rae
- School of Earth and Environmental Sciences, University of St Andrews, St Andrews, UK
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Nguyen S, Lee RS, Mohlmann E, Petrullo G, Blythe J, Ranieri I, McMenamin S. Craniofacial diversity across Danionins and the effects of TH status on craniofacial morphology of two Danio species. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.09.552728. [PMID: 37609193 PMCID: PMC10441423 DOI: 10.1101/2023.08.09.552728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
The model zebrafish ( Danio rerio ) belongs to the Danioninae subfamily with a range of informative phenotypes. However, the craniofacial diversity across the subfamily is not fully described. To better understand craniofacial phenotypes across Danioninae we used microCT and 3D geometric morphometrics to capture skull shapes from nine species. The Danio species examined showed largely similar skull shapes, although D. aesculapii , the sister species to D. rerio showed a unique morphology. Two non- Danio species examined, Chela dadiburjori and Devario aequipinnatus showed distinct skull morphologies unique from those of other species examined. Thyroid hormone regulates skeletal development and remodeling, and we asked if changes in developmental thyroid hormone metabolism could underlie some of the craniofacial diversity across Danioninae. We reared two Danio species under altered thyroid profiles, finding that hypothyroid individuals from both species showed corresponding morphological shifts in skull shape. Hypothyroid Danios showed skull morphologies closer to that of Chela and unlike any of the examined wild-type Danio species. We provide an examination of the evolved craniofacial diversity across Danioninae, and demonstrate that alterations to thyroid hormone have the capacity to create unique skull phenotypes.
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Abstract
Reductions in the thickness and extent of Antarctic ice shelves are triggering increased discharge of marine-terminating glaciers. While the impacts of recent changes are well documented, their role in modulating past ice-sheet dynamics remains poorly constrained. This reflects two persistent issues; first, the effective discrimination of sediments and landforms solely attributable to sub-ice-shelf deposition, and second, challenges in dating these records. Recent progress in deciphering the geological imprint of Antarctic ice shelves is summarised, including advances in dating methods and proxies to reconstruct drivers of change. Finally, we identify several challenges to overcome to fully exploit the paleo record. The recent collapses of ice shelves in Antarctica due to warming make it essential to understand past ice shelf conditions and mechanisms. Here Smith and colleagues review the latest progress in deciphering the geological imprint of Antarctic ice shelves via sediments, landforms and proxy indicators.
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Hauquier F, Ballesteros-Redondo L, Gutt J, Vanreusel A. Community dynamics of nematodes after Larsen ice-shelf collapse in the eastern Antarctic Peninsula. Ecol Evol 2016; 6:305-17. [PMID: 26811794 PMCID: PMC4716525 DOI: 10.1002/ece3.1869] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/19/2015] [Indexed: 11/28/2022] Open
Abstract
Free‐living marine nematode communities of the Larsen B embayment at the eastern Antarctic Peninsula were investigated to provide insights on their response and colonization rate after large‐scale ice‐shelf collapse. This study compares published data on the post‐collapse situation from 2007 with new material from 2011, focusing on two locations in the embayment that showed highly divergent communities in 2007 and that are characterized by a difference in timing of ice‐shelf breakup. Data from 2007 exposed a more diverse community at outer station B.South, dominated by the genus Microlaimus. On the contrary, station B.West in the inner part of Larsen B was poor in both numbers of individuals and genera, with dominance of a single Halomonhystera species. Re‐assessment of the situation in 2011 showed that communities at both stations diverged even more, due to a drastic increase in Halomonhystera at B.West compared to relatively little change at B.South. On a broader geographical scale, it seems that B.South gradually starts resembling other Antarctic shelf communities, although the absence of the genus Sabatieria and the high abundance of Microlaimus still set it apart nine years after the main Larsen B collapse. In contrast, thriving of Halomonhystera at B.West further separates its community from other Antarctic shelf areas.
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Affiliation(s)
- Freija Hauquier
- Marine Biology Research Group Ghent University Krijgslaan 281 B-9000 Ghent Belgium
| | | | - Julian Gutt
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research Am Handelshafen 12 D-27570 Bremerhaven Germany
| | - Ann Vanreusel
- Marine Biology Research Group Ghent University Krijgslaan 281 B-9000 Ghent Belgium
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Wouters B, Martin-Espanol A, Helm V, Flament T, van Wessem JM, Ligtenberg SRM, van den Broeke MR, Bamber JL. Dynamic thinning of glaciers on the Southern Antarctic Peninsula. Science 2015; 348:899-903. [DOI: 10.1126/science.aaa5727] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Surface heat led to ice-shelf demise. Nature 2014. [DOI: 10.1038/513282d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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