Beryllium isotope variations recorded in the Adélie Basin, East Antarctica reflect Holocene changes in ice dynamics, productivity, and scavenging efficiency

Bethany C. Behrens; Yusuke Yokoyama; Yosuke Miyairi; Adam D. Sproson; Masako Yamane; Francisco J. Jimenez-Espejo; Robert M. McKay; Katelyn M. Johnson; Carlota Escutia; Robert B. Dunbar

Quaternary Science Advances (Jul 2022)

Beryllium isotope variations recorded in the Adélie Basin, East Antarctica reflect Holocene changes in ice dynamics, productivity, and scavenging efficiency

Bethany C. Behrens,
Yusuke Yokoyama,
Yosuke Miyairi,
Adam D. Sproson,
Masako Yamane,
Francisco J. Jimenez-Espejo,
Robert M. McKay,
Katelyn M. Johnson,
Carlota Escutia,
Robert B. Dunbar

Affiliations

Bethany C. Behrens: Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan; Graduate Program on Environmental Science, University of Tokyo, Komaba, Meguro, Tokyo, 153-0041, Japan; Corresponding author. Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
Yusuke Yokoyama: Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan; Graduate Program on Environmental Science, University of Tokyo, Komaba, Meguro, Tokyo, 153-0041, Japan; Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Hongo, Bunkyō, Tokyo, 113-8654, Japan; Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushimacho, Yokosuka, Kanagawa Prefecture, 237-0061, Japan; Research School of Physics, The Australian National University, Acton ACT, 2601, Australia; Corresponding author. Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
Yosuke Miyairi: Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
Adam D. Sproson: Atmosphere and Ocean Research Institute, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan; Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushimacho, Yokosuka, Kanagawa Prefecture, 237-0061, Japan
Masako Yamane: Institute for Space-Earth Environmental Research, Nagoya University, Furocho, Chikusa, Nagoya, Aichi, 464-8601, Japan
Francisco J. Jimenez-Espejo: Biogeochemistry Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Natsushimacho, Yokosuka, Kanagawa Prefecture, 237-0061, Japan; Andalusian Earth Sciences Institute (IACT), CSIC-University of Granada, Armilla, Spain
Robert M. McKay: Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
Katelyn M. Johnson: Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand; GNS Science, Lower Hutt, New Zealand
Carlota Escutia: Andalusian Earth Sciences Institute (IACT), CSIC-University of Granada, Armilla, Spain
Robert B. Dunbar: School of Earth, Energy, and Environmental Sciences, Stanford University, Stanford, CA, USA

Journal volume & issue: Vol. 7
p. 100054

Abstract

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The Adélie Basin is a relatively small (∼1600 km2), semi-enclosed continental shelf bathymetric depression located adjacent to the Wilkes Subglacial Basin, a basin underlying a sector of the East Antarctic Ice Sheet that contains ∼3–4 m sea level equivalent of ice. Located within the Adélie Basin is a ∼184 m thick laminated sediment deposit, the Adélie Drift, ideal for examining regional changes in ice sheet and ocean dynamics. Here, we examine the ratio of reactive beryllium-10 to reactive beryllium-9 ((10Be/9Be)reac) in a marine sediment core obtained from the Adélie Drift to assess these changes during the Holocene epoch (11.7 ka BP to present). The (10Be/9Be)reac record provides insight into changes in freshwater input, primary productivity, and scavenging efficiency, while removing the influence of particle size on 10Be concentration. During the early Holocene, (10Be/9Be)reac ratios indicate increased meltwater discharge from ca. 11.7 to 10 ka BP, as grounded ice retreated from the Adélie Basin and adjacent bathymetric highs. After ∼10 ka BP, beryllium isotopes are influenced by scavenging efficiency and dilution controlled by ocean currents and accumulation rate, operating alongside meltwater input, suggesting there are additional factors to consider when using (10Be/9Be)reac as a proxy for ice shelf cover and glacial dynamics.

Published in Quaternary Science Advances

ISSN: 2666-0334 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Geography. Anthropology. Recreation; Auxiliary sciences of history: Archaeology
Website: https://www.journals.elsevier.com/quaternary-science-advances

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