Article
Environmental Sciences
Haidi Chen, F. Alexander Haumann, Lynne D. Talley, Kenneth S. Johnson, Jorge L. Sarmiento
Summary: The deep ocean releases large amounts of pre-industrial carbon dioxide to the atmosphere through upwelling in the Southern Ocean, which affects global climate and the ability of the Southern Ocean to absorb anthropogenic CO2. The release of CO2 is mainly concentrated in a band of upwelling waters between the Subantarctic Front and the wintertime sea-ice edge. The carbon chemistry in the subsurface waters is influenced by organic carbon remineralization and dissolution profiles, which have implications for the response of Southern Ocean CO2 fluxes to future changes in upwelling.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Review
Environmental Sciences
Elisabeth L. Sikes, Natalie E. Umling, Katherine A. Allen, Ulysses S. Ninnemann, Rebecca S. Robinson, Joellen L. Russell, Thomas J. Williams
Summary: The Southern Ocean plays a crucial role in regulating global CO2 levels and was instrumental in reducing atmospheric CO2 during the Last Glacial Maximum (LGM) and driving the subsequent increase during the deglaciation. There is still ongoing debate regarding the relative importance of Northern and Southern Hemisphere forcing during deglacial events. This review compares modern Southern Ocean conditions with those during the LGM and deglacial period, identifying key factors that initiated the glacial termination. The dynamics of the Southern Ocean appear to have been significant in initiating the termination of the LGM.
NATURE REVIEWS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Riley X. Brady, Mathew E. Maltrud, Phillip J. Wolfram, Henri F. Drake, Nicole S. Lovenduski
Summary: This study used a high-resolution ocean model simulation to show that Southern Ocean bathymetry plays a key role in bringing carbon-rich deep waters to the surface. The results indicate that 71% of carbon-enriched water upwelling across 1,000 m is concentrated near topographic features, and once upwelled to the near-surface layer, they exhibit relatively uniform pCO2 levels and DIC decorrelation timescales.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Multidisciplinary Sciences
Heike. H. H. Zimmermann, Kathleen. R. R. Stoof-Leichsenring, Viktor Dinkel, Lars Harms, Luise Schulte, Marc-Thorsten Huett, Dirk Nuernberg, Ralf Tiedemann, Ulrike Herzschuh
Summary: The disappearance of sea ice has caused significant changes in polar marine ecosystems over the past 20,000 years, as revealed by ancient DNA analysis of marine sediments off Kamchatka. The shift from a late-glacial ecosystem adapted to sea ice to an ice-free Holocene ecosystem is characterized by changes in dominant organisms. This study highlights the importance of ancient DNA in studying long-term ecosystem responses to climate change for improved risk assessment in ocean and cryosphere.
NATURE COMMUNICATIONS
(2023)
Article
Oceanography
Elizabeth Ellison, Ali Mashayek, Matthew Mazloff
Summary: Background mixing in the Southern Ocean has a significant impact on air-sea CO2 fluxes, primarily through altering the temperature and the distribution of dissolved inorganic carbon and alkalinity in the surface water.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
Elizabeth Ellison, Ali Mashayek, Matthew Mazloff
Summary: The Southern Ocean plays a crucial role in the exchange of carbon between the atmosphere and the ocean, and understanding the mixing processes in this region is important for accurate climate modeling. This study shows that altering the background mixing in the Southern Ocean can significantly impact the annual air-sea CO2 fluxes. The representation of small-scale turbulent mixing in climate models is essential for simulating global biogeochemical cycles accurately.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Oceanography
Matthis Auger, Jean-Baptiste Sallee, Pierre Prandi, Alberto C. Naveira Garabato
Summary: A novel multi-satellite product is used to study the seasonal cycle of sea surface height and geostrophic circulation in the subpolar Southern Ocean. Three main modes of variability are identified, all primarily driven by wind forcing. The first mode is associated with the seasonal variation of the subpolar gyres, consistent with Sverdrup dynamics. The second mode is related to the Antarctic Slope Current, showing a rapid circumpolar propagation along the continental slope consistent with the Southern Mode. The third mode appears to be driven by sea ice-modulated surface stress and leads to an offshore extension of the Antarctic Slope Current.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Multidisciplinary Sciences
Yuhao Dai, Jimin Yu, Haojia Ren, Xuan Ji
Summary: The Subantarctic Southern Ocean plays an important role in increasing atmospheric carbon dioxide partial pressure during glacial-interglacial transitions. Previous studies have focused on the biological pump but have largely overlooked the influences of the solubility pump. This research shows that the solubility pump has a stronger impact on Subantarctic surface-water pCO(2) variabilities during deglaciations compared to the biological pump.
NATURE COMMUNICATIONS
(2022)
Review
Environmental Sciences
Luisa Galgani, Steven A. Loiselle
Summary: The increasing presence of plastic in the ocean poses a major challenge in understanding its health and functioning dynamics, potentially impacting marine wildlife, habitats, microbial activity, and chemical processes. Research shows a continuum of effects of marine plastics on carbon, nutrients, and microbial processes, highlighting the need for further studies on the potential feedbacks of plastics on the changing ocean's carbon biogeochemistry.
ENVIRONMENTAL POLLUTION
(2021)
Article
Meteorology & Atmospheric Sciences
Chenyu Zhu, Jiaxu Zhang, Zhengyu Liu, Bette L. L. Otto-Bliesner, Chengfei He, Esther C. C. Brady, Robert Tomas, Qin Wen, Qing Li, Chenguang Zhu, Shaoqing Zhang, Lixin Wu
Summary: In this study, the physical processes leading to the warming of Antarctica during Heinrich Stadial 1 (HS1) were explored. The results show that increased meridional heat transport, particularly through ocean heat transport by mesoscale eddies, and atmospheric heat release through a strengthening zonal wavenumber-3 (ZW3) pattern can explain the warming in Antarctica during HS1.
JOURNAL OF CLIMATE
(2022)
Article
Environmental Sciences
L. Keppler, P. Landschuetzer, S. K. Lauvset, N. Gruber
Summary: Several methods have been developed to quantify the oceanic accumulation of anthropogenic carbon dioxide (CO2) in response to rising atmospheric CO2. Yet, we still lack a corresponding estimate of the changes in the total oceanic dissolved inorganic carbon (DIC). Our study extends the MOBO-DIC machine learning approach to estimate global monthly fields of DIC from 2004 through 2019. We find that the oceanic DIC pool increased linearly at an average rate of 3.2 +/- 0.7 Pg C yr(-1) over these 16 years, which is statistically indistinguishable from current estimates of anthropogenic CO2 uptake.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Geosciences, Multidisciplinary
Yuhao Dai, Jimin Yu, Patrick Rafter
Summary: The study reveals changes in the carbon storage in the deep Southern Ocean during specific periods of the Last Glacial Maximum, highlighting the impacts of sea-ice and stratification between Upper and Lower Circumpolar Deep Waters.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Cole F. Persch, Pedro Dinezio, Nicole S. Lovenduski
Summary: The study reveals the correlation between orbital precession and CO2 outgassing in the Southern Ocean. During periods of high precession, there is an anomalous release of CO2 from the Southern Ocean, which can be attributed to the poleward shift in the southern westerly winds, enhanced Southern Ocean meridional overturning, and an increase in the surface ocean partial pressure of CO2 along the core of the Antarctic Circumpolar Current.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
William R. Gray, Casimir de Lavergne, Robert C. Jnglin Wills, Laurie Menviel, Paul Spence, Mark Holzer, Masa Kageyama, Elisabeth Michel
Summary: The Southern Hemisphere westerly winds have a significant impact on the deep ocean circulation and carbon storage. This study reconstructs the changes in the Southern Hemisphere surface westerlies during the last deglaciation using planktic foraminiferal delta O-18 data and climate models. The results show a 4.8-degree equatorward shift and a 25% weakening of the westerlies during the Last Glacial Maximum compared to the mid-Holocene. Climate models underestimate this shift. According to the reconstruction, the poleward shift in the westerlies closely correlates with the rise in atmospheric CO2.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Frank J. Pavia, Shouyi Wang, Jennifer Middleton, Richard W. Murray, Robert F. Anderson
Summary: The text discusses the deep ocean as a reservoir for storing carbon dioxide removed from the atmosphere during Pleistocene glacial periods, as well as the enhanced efficiency of the biological pump in the deep ocean during glacial periods.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geology
Morten Lunde Nielsen, Mirinae Lee, Hong Chin Ng, Jeremy C. Rushton, Katharine R. Hendry, Ji-Hoon Kihm, Arne T. Nielsen, Tae-Yoon S. Park, Jakob Vinther, Philip R. Wilby
Summary: The correct interpretation of soft-bodied fossils relies on a thorough understanding of their taphonomy. This study investigates the mineral replacements in panarthropod fossils from the Sirius Passet Lagerstatte and reveals the potential impacts of deeper burial and metamorphism on fossil preservation. The study provides critical context for interpreting the Sirius Passet biota and identifies late-stage overprints in other biotas.
Article
Geology
Zhewen Xu, Tao Li, Gaojun Li, David W. Hedding, Yunqiang Wang, Long-Fei Gou, Liang Zhao, Jun Chen
Summary: Lithium isotopes have the potential to trace Earth surface processes. The study proposes an in situ mechanism involving evapotranspiration to explain the formation of high δLi-7 values and provides evidence from the Chinese Loess Plateau. The research suggests that the influence of evapotranspiration on riverine δLi-7 may partly explain the variations of seawater δLi-7.
Article
Geochemistry & Geophysics
James Kershaw, Joseph A. Stewart, Ivo Strawson, Maria Luiza de Carvalho Ferreira, Laura F. Robinson, Katharine R. Hendry, Ana Samperiz, Andrea Burke, James W. B. Rae, Rusty D. Day, Peter J. Etnoyer, Branwen Williams, Vreni Haussermann
Summary: Based on the study of modern Stylasteridae corals, it is found that [Ba]SW and sample mineralogy are the main factors influencing coral Ba/Ca ratios, while seawater temperature has a weak influence. Paired Sr/Ca measurements suggest that the variability in scleractinian Ba/Ca may be related to varying degrees of Rayleigh fractionation during calcification. Stylasteridae corals have the potential to be an important new archive for paleoceanographic studies.
Article
Geochemistry & Geophysics
Sang Chen, Eloise F. M. Littley, James W. B. Rae, Christopher D. Charles, Yunbin Guan, Jess F. Adkins
Summary: Deep-sea corals serve as an important record of past oceans and studying their vital effects is crucial for paleoceanographic applications. By analyzing stable isotopes, minor and trace metals, we observed spatially coherent tracer correlations in individual corals. Our findings provide insights into the biomineralization mechanisms and the response of marine calcification to environmental stress. Understanding these mechanisms is essential for accurate use of deep-sea coral tracers and predicting the impact of ocean acidification.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geography, Physical
Tao Li, Tianyu Chen, Laura F. Robinson, Maoyu Wang, Gaojun Li, Yuanyuan Liu, Timothy D. J. Knowles
Summary: The loess-paleosol sequence on the Chinese Loess Plateau presents challenges in absolute dating due to the lack of directly datable materials. Fossil land snail shells have the potential for U-series dating of the loess deposits, but this method has not been extensively explored. This study investigates the geochemistry and diagenetic imprints of fossil land snail shells from the Mangshan loess-paleosol sequence in central China, demonstrating the potential for age determination of dust deposits using U-series dating.
QUATERNARY GEOCHRONOLOGY
(2023)
Article
Geochemistry & Geophysics
Qian Liu, Laura F. Robinson, Erica Hendy, Maria G. Prokopenko, Timothy D. J. Knowles, Tao Li, Ana Samperiz
Summary: Deep-sea bamboo corals have been used as archives for reconstructing past ocean changes, but the interpretation of geochemical signals recorded in their organic nodes, particularly regarding water depth, remains uncertain. Through isotopic analysis of bamboo corals collected from the central and eastern tropical Atlantic, contrasting results were found between the two regions. The carbon source for bamboo coral organic nodes may not always reside in the mixed layer, especially in oligotrophic regions, which has implications for age model development.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geosciences, Multidisciplinary
Tao Li, Gaojun Li, Tianyu Chen, Youbin Sun, Qiuzhen Yin, Zhipeng Wu, Laura F. Robinson, Le Li, Zeke Zhang, Xianqiang Meng, Liang Zhao, Junfeng Ji, Jun Chen
Summary: By integrating multi-proxy records from the loess sections on the central Chinese Loess Plateau, we find that the intensification of the East Asian winter monsoon during glacial inceptions is associated with millennial perturbations in the atmospheric circulation in response to abrupt North Atlantic cooling triggered by insolation. This climate teleconnection between the North Atlantic and East Asia is particularly effective when the Northern Hemisphere ice sheets reach a critical size.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Andre N. Paul, Joseph A. Stewart, Samuele Agostini, Linda A. Kirstein, Jan C. M. De Hoog, Ivan P. Savov, Kristina Walowski, James W. B. Rae, Tim Elliott
Summary: This study presents a low-blank sample preparation procedure for boron isotope measurement in silicate rocks using MC-ICP-MS. The method effectively addresses the challenges of volatilisation during silicate dissolution and contamination during chemical purification. The results demonstrate the accuracy and consistency of the method and reveal the heterogeneity in boron isotopes in the upper mantle.
GEOSTANDARDS AND GEOANALYTICAL RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Tianyu Chen, Laura F. Robinson, Tao Li, Andrea Burke, Xu Zhang, Joseph A. Stewart, Nicky J. White, Timothy D. J. Knowles
Summary: Proxy-based studies have linked the pre-industrial atmospheric p(CO2) rise to changes in Southern Ocean overturning. However, the history of polar ocean overturning and ventilation through the Holocene remains poorly constrained. This study suggests that long-term polar ocean overturning is not responsible for millennial atmospheric pCO(2) evolution, instead, changes in carbon redistribution and land organic carbon stock might regulate CO2 budget during this period.
Article
Chemistry, Analytical
Cheng Cao, Tao Li, Tianyu Chen, Gaojun Li, Wei Li, Jun Chen
Summary: There has been a growing interest in using lithium isotopes in marine carbonates to trace chemical weathering and clay formation. However, it is technically challenging to determine the Li isotope composition in carbonate samples due to the imperfect Li separation and low Li concentration in carbonates. A dual-column chromatography system for Li purification is presented, which has a large loading capacity, complete Li recovery, and efficient elution time. The procedure is validated with certified reference materials and the precision of Li isotope measurement is high.
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2023)
Article
Geosciences, Multidisciplinary
Eric W. Wolff, Andrea Burke, Laura Crick, Emily A. Doyle, Helen M. Innes, Sue H. Mahony, James W. B. Rae, Mirko Severi, R. Stephen J. Sparks
Summary: Volcanic eruptions are the main cause of climate variability, but estimating their frequency is challenging. Analysis of an Antarctic ice core showed that the frequency of eruptions has increased linearly over the past 200,000 years. The study also confirmed that the largest peaks in the ice core record are mostly from stratospheric eruptions.
CLIMATE OF THE PAST
(2023)
