Article
Geochemistry & Geophysics
Maciej M. Telesinski, Mohamed M. Ezat, Francesco Muschitiello, Henning A. Bauch, Robert F. Spielhagen
Summary: Changes in ocean circulation play a crucial role in centennial-to-millennial scale climate variability during the last deglaciation. Through sediment records from the Nordic Seas, researchers studied radiocarbon ventilation ages to reconstruct past variations in watermass overturning. Variability in ventilation ages among different records suggest regional shifts in deep convection and emphasize the importance of using uniform material for reconstructing bottom water ventilation histories.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
A. Solodoch, A. L. Stewart, A. McC. Hogg, A. K. Morrison, A. E. Kiss, A. F. Thompson, S. G. Purkey, L. Cimoli
Summary: This study uses a global high-resolution ocean/sea-ice simulation and passive tracer deployments to examine the export pathways of Antarctic Bottom Water (AABW). The results show that AABW from different source regions are blended during their export, with Weddell Sea- and Prydz Bay-sourced AABW mainly exported to the Atlantic and Indian Oceans, while Ross Sea- and Adelie Land-sourced AABW mainly exported to the Pacific Ocean. This has important implications for the three-dimensional structure of the global overturning circulation.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Thomas W. N. Haine, Renske Gelderloos, Miguel A. Jimenez-Urias, Ali H. Siddiqui, Gerard Lemson, Dimitri Medvedev, Alex Szalay, Ryan P. Abernathey, Mattia Almansi, Christopher N. Hill
Summary: Computational oceanography focuses on studying ocean phenomena through numerical simulation, with the exponential growth in global ocean observations and simulation fidelity driven by information technology. This rapid growth is shifting the importance of field measurements and numerical simulations in oceanographic research, leading to the maturation of computational oceanography as a branch of marine science on par with observational oceanography. Despite specific limits and challenges, there are numerous opportunities identified for the future of computational oceanography, including the prospect of hybrid computational and observational approaches to enhance understanding of the ocean.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
Remi Amiraux, David J. Yurkowski, Philippe Archambault, Marie Pierrejean, C. J. Mundy
Summary: The traditional view that the benthic compartment is simpler in structure compared to the pelagic compartment is challenged in this study, which illustrates the presence of a subweb in the benthic realm with similar complexity to the pelagic counterpart, including megafaunal-predatory sea stars equivalent to iconic polar bears.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Multidisciplinary Sciences
Patrick A. Rafter, William R. Gray, Sophia K. Hines, Andrea Burke, Kassandra M. Costa, Julia Gottschalk, Mathis P. Hain, James W. B. Rae, John R. Southon, Maureen H. Walczak, Jimin Yu, Jess F. Adkins, Timothy DeVries
Summary: This study provides several benchmarks for circulation and ventilation of the Atlantic, Southern, and Pacific deep-sea since the last ice age using measurements of marine fossil radiocarbon. The findings highlight the significant role of changes in overturning circulation in glacial deep-sea carbon storage and the simultaneous reduction of atmospheric CO2.
Article
Meteorology & Atmospheric Sciences
Byju Pookkandy, Heather Graven, Adrian Martin
Summary: Radiocarbon (C-14) is a valuable tracer of ocean circulation with potential to investigate past climate change. However, the relationship between ocean C-14 and recent ocean circulation changes has not been studied. This study uses a model to simulate the effect of ocean circulation trends and variability on C-14 and finds that C-14 variability is generally anti-correlated with potential density variability. The simulated variations are larger than measurement uncertainty, suggesting that increment C-14 data could be a useful tracer of circulation changes.
Article
Geosciences, Multidisciplinary
Sophia K. V. Hines, Louise Bolge, Steven L. Goldstein, Christopher D. Charles, Ian R. Hall, Sidney R. Hemming
Summary: The study found that the circulation structure in the far South Atlantic underwent changes throughout the last glacial cycle, contradicting the common conception of the upper circulation cell in the Atlantic being shoaled at the Last Glacial Maximum. Despite little change in mid-depth ocean structure, greater stratification between mid-depth and abyssal sites developed, which may have contributed to glacial carbon storage in the deep ocean.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Multidisciplinary Sciences
Yoshihiko Ohashi, Michiyo Yamamoto-Kawai, Kazuya Kusahara, Ken'ichi Sasaki, Kay Ohshima
Summary: This study used CFC and SF6 tracers to investigate the timescale of Antarctic Bottom Water (AABW) spreading in Cape Darnley, East Antarctica. The results showed that the age of the bottom water varied with location, indicating different spreading processes of AABW.
SCIENTIFIC REPORTS
(2022)
Article
Oceanography
L. Renault, P. Marchesiello, M. Contreras
Summary: Bottom drag and top drag are energy dissipation processes in the oceanic boundary layers that play important roles in regulating western boundary currents like the Gulf Stream. The sensitivity of model results to bottom drag parameterization has not been considered when top drag is present. A study in the North Atlantic basin shows that the energy sink due to bottom drag increases when top drag is neglected, but it does not fully compensate for the absence of top drag. Therefore, both top and bottom drags must be considered for a realistic representation of Gulf Stream dynamics and energy pathways.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Environmental Sciences
David H. Shull
Summary: The study reveals the presence of corrosive bottom water in Bellingham Bay, mainly influenced by water column respiration and sediment processes. A two-layer box model evaluated the main factors leading to water acidification and predicted the variations in bottom water properties during spring.
ESTUARIES AND COASTS
(2021)
Article
Geosciences, Multidisciplinary
Andrew L. Stewart, Xiaoyang Chi, Aviv Solodoch, Andrew McC Hogg
Summary: The transport of Antarctic Bottom Water is influenced by wind stress fluctuations, which drive fluctuations in transport on time scales shorter than 2 years, mainly due to differences in response time scales of topographic and interfacial form stresses to wind variability. This implies that the transport variability of Antarctic Bottom Water can largely be reconstructed from surface wind stress alone.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Oceanography
Carlyn R. Schmidgall, Yidongfang Si, Andrew L. Stewart, Andrew F. Thompson, Andrew McC. Hogg
Summary: This study investigates the influence of the Antarctic Circumpolar Current (ACC) on the transport and transformation of Antarctic Bottom Water (AABW) using process-oriented model simulations. The results show that the forcing and geometry of the ACC play a crucial role in directing the flow of AABW. Changes in seafloor elevation relative to the thickness of the AABW layer can significantly affect the northward transport of AABW and its distribution between basins.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2023)
Article
Geosciences, Multidisciplinary
Hannah Zanowski, Alexandra Jahn, Sifan Gu, Zhengyu Liu, Thomas M. Marchitto
Summary: During the last deglaciation, changes in Earth's climate and ocean circulation significantly influenced the evolution of deep Pacific radiocarbon ages, with circulation changes gradually becoming the dominant factor controlling radiocarbon age variations.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2022)
Article
Geography, Physical
Blanca Ausin, Michael Sarnthein, Negar Haghipour
Summary: This study utilizes sediment core data from the 'Shackleton Sites' to provide new insights into past changes in surface and deep-ocean reservoir ages over the last 23,000 years. The results reveal differences in marine reservoir ages compared to previous estimates, primarily reflecting short-term changes in local hydrography.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geography, Physical
Romi Nambiar, Ravi Bhushan, Harsh Raj
Summary: This study investigates the past variations in bottom water redox condition in the Indian Ocean by analyzing multiple redox proxies and organic carbon in sediment core samples from the Arabian Sea. The results show significant changes in oxygenation conditions in response to changes in ocean circulation, with the bottom water in the northern Indian Ocean being more oxic during the Last Glacial Maximum (LGM) than the deglacial period. It is suggested that the contribution of Antarctic Bottom Waters (AABW) to the Indian Ocean increased during LGM, resulting in higher oxygen conditions.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Oceanography
Charlotte Breitkreuz, Andre Paul, Takasumi Kurahashi-Nakamura, Martin Losch, Michael Schulz
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2018)
Article
Meteorology & Atmospheric Sciences
Andrea Klus, Matthias Prange, Vidya Varma, Michael Schulz
Article
Meteorology & Atmospheric Sciences
Sri D. Nandini-Weiss, Matthias Prange, Klaus Arpe, Ute Merkel, Michael Schulz
INTERNATIONAL JOURNAL OF CLIMATOLOGY
(2020)
Article
Geosciences, Multidisciplinary
Martin Koelling, Ilham Bouimetarhan, Marshall W. Bowles, Thomas Felis, Tobias Goldhammer, Kai-Uwe Hinrichs, Michael Schulz, Matthias Zabel
Article
Geosciences, Multidisciplinary
Markus Raitzsch, Jelle Bijma, Torsten Bickert, Michael Schulz, Ann Holbourn, Michal Kucera
Summary: The middle Miocene climate transition around 14 million years ago marked a fundamental step towards the current ice-house climate, with an increase in delta O-18 and transient delta(3C) in the deep ocean, indicating rapid expansion of the East Antarctic Ice Sheet. The variation of atmospheric CO2 during this time interval has been debated, with sparse and contradictory proxy records. Using boron isotopes in planktonic foraminifers, researchers found that long-term pCO2 varied at 402 kyr periodicity between 14.3 and 13.2 Ma, closely linked to global delta C-13 variation influenced by precessional insolation forcing modulated by eccentricity. The drop in pCO2 before 13.9Ma may have facilitated Antarctic ice-sheet expansion, leading to carbon cycle changes through sea-level fall, deep-water ventilation, and shelf-to-basin shift of carbonate burial.
CLIMATE OF THE PAST
(2021)
Article
Ecology
Kaveh Purkiani, Andre Paul, Annemiek Vink, Maren Walter, Michael Schulz, Matthias Haeckel
Article
Geosciences, Multidisciplinary
Takasumi Kurahashi-Nakamura, Andre Paul, Guy Munhoven, Ute Merkel, Michael Schulz
GEOSCIENTIFIC MODEL DEVELOPMENT
(2020)
Article
Paleontology
Andreia Rebotim, Antje Helga Luise Voelker, Lukas Jonkers, Joanna J. Waniek, Michael Schulz, Michal Kucera
JOURNAL OF MICROPALAEONTOLOGY
(2019)
Article
Ecology
Kerstin Kretschmer, Lukas Jonkers, Michal Kucera, Michael Schulz
Article
Geosciences, Multidisciplinary
Amanda Frigola, Matthias Prange, Michael Schulz
GEOSCIENTIFIC MODEL DEVELOPMENT
(2018)
Article
Geochemistry & Geophysics
Christoph Haeggi, Cristiano M. Chiessi, Ute Merkel, Stefan Mulitza, Matthias Prange, Michael Schulz, Enno Schefuss
EARTH AND PLANETARY SCIENCE LETTERS
(2017)
Article
Geosciences, Multidisciplinary
Rike Voelpel, Andre Paul, Annegret Krandick, Stefan Mulitza, Michael Schulz
GEOSCIENTIFIC MODEL DEVELOPMENT
(2017)
Article
Ecology
Andreia Rebotim, Antje H. L. Voelker, Lukas Jonkers, Joanna J. Waniek, Helge Meggers, Ralf Schiebel, Igaratza Fraile, Michael Schulz, Michal Kucera
Article
Geosciences, Multidisciplinary
R. Voelpel, S. Mulitza, A. Paul, J. Lynch-Stieglitz, M. Schulz
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2019)
Article
Geosciences, Multidisciplinary
Andrea Klus, Matthias Prange, Vidya Varma, Louis Bruno Tremblay, Michael Schulz
CLIMATE OF THE PAST
(2018)