Article
Geochemistry & Geophysics
F. Hodel, R. Grespan, M. de Rafelis, G. Dera, C. Lezin, E. Nardin, D. Rouby, M. Aretz, M. Steinnman, M. Buatier, F. Lacan, C. Jeandel, V. Chavagnac
Summary: The relationship between the establishment of the Antarctic Circumpolar Current (ACC) and the onset of the Oligocene glaciation is debated due to uncertainties in the timing of the Drake Passage gateway opening. The connection and deepening of the Southern Atlantic and Pacific oceans suggest that the ACC onset occurred around 31-26 million years ago, prior to the onset of the Oligocene glaciation at 33.7 Ma, indicating that atmospheric pCO(2) may have played a significant role in triggering the glaciation.
Article
Oceanography
Li Zhou, Qiang Wang, Mu Mu, Kun Zhang
Summary: The accurate prediction of the Antarctic circumpolar current (ACC) transport remains challenging due to its high nonlinearity. This study investigates the sudden shifts in ACC transport through Drake Passage (DP) and finds that the optimal precursor (OPR) at specific depths and structures in the middle DP plays a crucial role in triggering sudden reductions in transport. Baroclinic instability is identified as a dominant factor in the development of OPRs, suggesting that careful monitoring of deep-layer density perturbations in the Southern Ocean is important for short-range ACC transport prediction.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Multidisciplinary Sciences
Shuzhuang Wu, Lester Lembke-Jene, Frank Lamy, Helge W. Arz, Norbert Nowaczyk, Wenshen Xiao, Xu Zhang, H. Christian Hass, Juergen Titschack, Xufeng Zheng, Jiabo Liu, Levin Dumm, Bernhard Diekmann, Dirk Nuernberg, Ralf Tiedemann, Gerhard Kuhn
Summary: Research has shown significant changes in the speed of the Antarctic Circumpolar Current (ACC) during glacial and interglacial periods, with a stronger circulation in the Antarctic during glacials. Additionally, the ACC is closely linked to millennial-scale climate oscillations in the Southern Hemisphere, amplified through changes in Antarctic sea ice extent.
NATURE COMMUNICATIONS
(2021)
Article
Geography, Physical
Sunghan Kim, Jae Il Lee, Kyu-Cheul Yoo, Min Kyung Lee, Young-Suk Bak, Myung-Il Kang, Sookwan Kim, Jinku Park
Summary: Oceanographic conditions in the Southern Ocean are influenced by the oceanic frontal system, which is in turn affected by glacial-interglacial changes in the cryosphere. These changes impact surface water productivity, nutrient utilization, bottom water chemistry, and bottom current intensity. The study highlights the importance of light availability and sea ice duration/extent in regulating surface water production. The findings also suggest the need for further research on the response of the Southern Ocean to the Mid-Brunhes Event.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Geography, Physical
Shuzhuang Wu, Gerhard Kuhn, Helge W. Arz, Lester Lembke-Jene, Ralf Tiedemann, Frank Lamy, Bernhard Diekmann
Summary: This study investigates the sources and transport pathways of terrigenous sediments in the Drake Passage region over the past 140 thousand years. The Antarctic Circumpolar Current (ACC) is identified as the key driver for sediment dispersal in this area. Glacial mass accumulation rates, sea level changes, and ACC strength variations have all influenced terrigenous sediment supply and deposition in the Drake Passage region.
GLOBAL AND PLANETARY CHANGE
(2023)
Article
Oceanography
Manuel O. Gutierrez-Villanueva, Teresa K. Chereskin, Janet Sprintall, John A. Goff
Summary: Radiation and breaking of internal lee waves in the Southern Ocean have been studied to understand their role in the energy and heat budget. This study estimated the linear lee-wave energy radiation and local dissipation using a time series of stratification and near-bottom currents. The results showed that most of the lee-wave energy radiation occurred in the Polar Front Zone of the Antarctic Circumpolar Current (ACC), and both baroclinic and barotropic instabilities influenced the conversion to lee waves in this region. The study also found that the local dissipation of lee-wave energy was less than 10%, which is contrary to previous numerical predictions.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Engineering, Aerospace
Camila Artana, Ramiro Ferrari, Clement Bricaud, Jean-Michel Lellouche, Gilles Garric, Nathalie Sennechael, Jae-Hak Lee, Young-Hyang Park, Christine Provost
Summary: The study compared velocities from the 25-year GLORYS12 Mercator Ocean reanalysis with satellite altimetry-derived surface velocities and in-situ velocity measurements. The model velocities showed good agreement with altimetry derived velocities and in-situ measurements, with significant correlations observed. The assessment of GLORYS12 velocities in Drake Passage is encouraging for monitoring the regional variability of the Antarctic Circumpolar Current (ACC).
ADVANCES IN SPACE RESEARCH
(2021)
Article
Environmental Sciences
Jingxi Li, Di Zhang, Fenglei Gao, Chengjun Sun, Wei Cao, Fenghua Jiang
Summary: This study analyzed the distribution characteristics and correlations of 11 trace elements in surface seawater collected from the Drake Passage and Antarctic Peninsula sea area. The concentration of different elements showed remarkable differences, with relatively high concentrations of Mn, Mo, Zn, and U. The concentration of trace elements in the Drake Passage water was relatively low, possibly due to the existence of a westerly drift that enhances large circulating currents. Mn, Co, Cu, Zn, Cd, and Pb showed relatively high concentrations at more stations, with Mn, Co, and Cd mainly found in shallow water areas. Good linear correlations were observed between certain element pairs.
MARINE POLLUTION BULLETIN
(2022)
Article
Geosciences, Multidisciplinary
Luwei Yang, Maxim Nikurashin, Andrew McC. Hogg, Bernadette M. Sloyan
Summary: Using an idealized model of the Southern Ocean and a lee wave parameterization, this study finds that the sensitivity of the Antarctic Circumpolar Current (ACC) to wind increases when lee wave drag is considered. This is due to the dependence of lee wave drag on the bottom stratification, which leads to increased eddy dissipation and stronger eddy generation to compensate for the increased ACC shear (baroclinic transport).
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Oceanography
S. A. Ostroumova, I. D. Drozd, D. I. Frey
Summary: This study compares different methods for detecting the boundaries of the Antarctic Circumpolar Current using satellite altimetry data. The research finds that the position of the boundaries is subject to long-term trends and is influenced by variations in mean sea level. The study also identifies a statistically significant long-term trend of sea level rise near the boundaries of the Antarctic Circumpolar Current. These findings are important for understanding the dynamics and structure of this current and the global distribution of heat.
Article
Ecology
Nele Manon Vollmar, Karl-Heinz Baumann, Mariem Saavedra-Pellitero, Ivan Hernandez-Almeida
Summary: The Southern Ocean is undergoing significant changes that may impact the composition and distribution of pelagic plankton communities. This study investigates the (sub-)fossil coccolith assemblages preserved in surface sediments of southernmost Chile and the Drake Passage. The findings highlight the biodiversity and morphological diversity of coccoliths, emphasizing their response to changing environmental conditions.
Article
Geosciences, Multidisciplinary
Lingwei Li, Zhengyu Liu, Jean Lynch-Stieglitz, Chengfei He, Sifan Gu, Jiaxu Zhang, Bette Otto-Bliesner
Summary: The Antarctic Circumpolar Current (ACC) is crucial for the exchange of ocean properties between basins, and reconstructing ACC baroclinic transport is important for assessing its sensitivity to climate change. Using end-member water masses, the density profile across the ACC at the Last Glacial Maximum (LGM) can be effectively reconstructed. Additional pore fluid observations at 1,000 m depth can significantly improve transport reconstruction and help constrain changes in ACC transport during the LGM.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geography, Physical
Nina-Marie Lesic, Katharina Teresa Streuff, Gerhard Bohrmann, Gerhard Kuhn
Summary: South Georgia, a sub-Antarctic island in the Southern Ocean, exhibits highly dynamic ice cap waxing and waning, as well as geomorphological and sedimentological changes. This study provides new evidence of a shelf-wide glaciation during the Last Glacial Maximum (LGM) and suggests rapid, but stepwise ice retreat during deglaciation. The findings contribute to a better understanding of the glacial history and climate variability in this region.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Zoe A. Roseby, James A. Smith, Claus-Dieter Hillenbrand, Claire S. Allen, Amy Leventer, Kelly Hogan, Matthieu J. B. Cartigny, Brad E. Rosenheim, Gerhard Kuhn, Robert D. Larter
Summary: This study investigates changes in biological productivity during the Last Glacial Transition (19-11 cal kyr BP) using sediment cores recovered from the Anvers-Hugo Trough (AHT), western Antarctic Peninsula shelf. The study reveals that seasonally open marine conditions were established by 13.6 cal kyr BP, but the accumulation of laminated diatomaceous oozes (LDOs) did not start until 11.5 cal kyr BP. The deposition of LDOs in AHT is associated with the early Holocene climatic optimum, increased atmospheric/ocean temperatures, high rates of sea and glacial ice melt, and the formation of a well-stratified water column.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Shulan Ge, Zhihua Chen, Qingsong Liu, Li Wu, Yi Zhong, Helin Liu, Jianxing Liu, Qiang Zhang
Summary: This study investigates the response of the East Antarctic Ice Sheet to glacial-interglacial climatic cycles in the late Pleistocene. By analyzing magnetic properties, isotopic compositions and ratios in gravity cores from Prydz Bay, the researchers identify distinct patterns in the glacial and interglacial periods. They also analyze the sources of Antarctic continental sediments and ice drainage flow patterns. The study provides important insights into the dynamics of the East Antarctic Ice Sheet and its implications for global climate and sea level rise projections.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geochemistry & Geophysics
Florian Kurzweil, Olaf Dellwig, Martin Wille, Ronny Schoenberg, Helge W. Arz, Carsten Muenker
Summary: Manganese oxides preferentially adsorb light tungsten isotopes in marine environments, leading to heavier W isotope compositions in seawater. The stable W isotope data in sediments are related to the oxygenation level of seawater, indicating its potential as a tracer for early Earth redox reconstructions.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Correction
Multidisciplinary Sciences
Shuzhuang Wu, Lester Lembke-Jene, Frank Lamy, Helge W. Arz, Norbert Nowaczyk, Wenshen Xiao, Xu Zhang, H. Christian Hass, Jurgen Titschack, Xufeng Zheng, Jiabo Liu, Levin Dumm, Bernhard Diekmann, Dirk Nurnberg, Ralf Tiedemann, Gerhard Kuhn
NATURE COMMUNICATIONS
(2022)
Article
Limnology
Grzegorz Scholtysik, Tobias Goldhammer, Helge W. Arz, Matthias Moros, Ralf Littke, Michael Hupfer
Summary: The study found that the enrichment and burial of iron, manganese, and phosphorus in Lake Arendsee in Germany have been affected by changes in redox conditions, and sediments also contain higher levels of manganese and iron.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Geochemistry & Geophysics
Jiabo Liu, Norbert R. Nowaczyk, Xiaodong Jiang, Yi Zhong, Richard Wirth, Qingsong Liu, Helge W. Arz
Summary: The successful reconstruction of paleomagnetic secular variations from anoxic Black Sea sediments greatly extends the application of paleomagnetism in sediments deposited in water with reducing sub-surface environments, where paleomagnetic data are generally sparse.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Multidisciplinary Sciences
Shinya Iwasaki, Lester Lembke-Jene, Kana Nagashima, Helge W. Arz, Naomi Harada, Katsunori Kimoto, Frank Lamy
Summary: The study reveals significant variations in carbonate ion concentrations in the Southern Ocean deep water during the Last Glacial Maximum and Deglaciation, using an X-ray Micro-Computer-Tomography method. The findings suggest that the export of low-carbon deep water from the Pacific to the Atlantic significantly reduced carbon storage in the Southern Ocean. This highlights the importance of Pacific-Southern Ocean deep-water reconfiguration for late-glacial oceanic carbon storage and subsequent deglacial oceanic-atmospheric CO2 transfer.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Juan Muglia, Stefan Mulitza, Janne Repschlaeger, Andreas Schmittner, Lester Lembke-Jene, Lorraine Lisiecki, Alan Mix, Rajeev Saraswat, Elizabeth Sikes, Claire Waelbroeck, Julia Gottschalk, Joerg Lippold, David Lund, Gema Martinez-Mendez, Elisabeth Michel, Francesco Muschitiello, Sushant Naik, Yusuke Okazaki, Lowell Stott, Antje Voelker, Ning Zhao
Summary: We introduce the OC3 working group database, which contains oxygen and carbon stable isotope ratios from benthic foraminifera in deep ocean sediment cores. The database includes globally distributed coring sites with metadata, isotopic, and chronological information. The data captures the deep water mass structure and differences between the early deglaciation and Last Glacial Maximum. It provides a useful tool for studying the physical and biogeochemical changes of the ocean during the last deglaciation.
Article
Oceanography
Gaston Kreps, Lester Lembke-Jene, Silvia Romero, Ramiro Ferrari, Frank Lamy, Elda Miramontes
Summary: This study focused on the intensity and variability of bottom currents in the Drake Passage and found that they are disconnected from surface dynamics and strongly controlled by the rough topography. The variability patterns of bottom currents are related to local topography and may affect erosion and deposition rates differently. High-speed current events were observed, but contourite drifts accumulated preferentially in zones of slow and stable bottom currents.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Geosciences, Multidisciplinary
Rossano Ciampalini, Elizabeth J. Kendon, Jose A. Constantine, Marcus Schindewolf, Ian R. Hall
Summary: This study used high-resolution rainfall projections to simulate soil erosion response in the Rother catchment in West Sussex, England. The results show that future soil loss is likely to increase and surface runoff is expected to rise, highlighting the effectiveness of using high-resolution rainfall projections for assessing spatial variability in soil erosion.
Article
Geosciences, Multidisciplinary
Maria-Elena Vorrath, Juliane Mueller, Paola Cardenas, Thomas Opel, Sebastian Mieruch, Oliver Esper, Lester Lembke-Jene, Johan Etourneau, Andrea Vieth-Hillebrand, Niko Lahajnar, Carina B. Lange, Amy Leventer, Dimitris Evangelinos, Carlota Escutia, Gesine Mollenhauer
Summary: The reconstruction of past sea-ice distribution in the Southern Ocean is crucial for understanding ice-ocean-atmosphere interactions and assessing Earth system and Antarctic ice sheet models. This study focused on the northern Antarctic Peninsula (NAP) and utilized marine sediment cores to reveal the long-term sea-ice history. Sea-ice biomarkers and diatom assemblages were used for reconstructions, while ocean temperatures were reconstructed using glycerol dialkyl glycerol tetraethers (GDGTs). The findings show varying sea-ice trends throughout different periods, with a maximum ice cover during the Antarctic Cold Reversal and decreasing ice cover during the Middle Holocene.
CLIMATE OF THE PAST
(2023)
Article
Geosciences, Multidisciplinary
Mengli Cao, Jens Hefter, Ralf Tiedemann, Lester Lembke-Jene, Vera D. Meyer, Gesine Mollenhauer
Summary: Arctic warming and sea level change can lead to permafrost thaw and mobilization. This study uses sedimentary records from the Amur and Yukon rivers to analyze changes in vegetation associated with permafrost mobilization. The results show that vegetation change and wetland expansion started earlier in the Yukon basin compared to the Okhotsk Sea. The permafrost in the Amur basin began to remobilize during the Pre-Boreal period. The study also finds that lignin and lipid biomarkers are transported to the ocean through the same pathway under conditions of rapid sea level rise and shelf flooding.
CLIMATE OF THE PAST
(2023)
Article
Environmental Sciences
Bjoern Klaes, Gerhard Woerner, Katrina Kremer, Klaus Simon, Andreas Kronz, Denis Scholz, Carsten W. Mueller, Carmen Hoeschen, Julian Struck, Helge Wolfgang Arz, Soeren Thiele-Bruhn, Daniel Schimpf, Rolf Kilian
Summary: Volcanic ash layers in southernmost South America serve as important indicators for studying paleoclimate and paleoenvironment, but accurate dating of these ash layers is crucial. This study presents a new high-resolution chronology of tephra deposits from Mt. Burney and possibly Aguilera, based on geochemical analyses of stalagmites. The findings provide valuable information for tephrochronology in the region, as well as potential insights into large-volume explosive volcanism off South America.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Maria H. Toyos, Gisela Winckler, Helge W. Arz, Lester Lembke-Jene, Carina B. Lange, Gerhard Kuhn, Frank Lamy
Summary: Changes in export production in the Southern Ocean have significant impacts on biogeochemistry and climate. Past studies have found increased export production in the subantarctic southeastern Pacific, potentially influenced by Patagonian Ice Sheet dynamics and iron fertilization. However, export production near the Drake Passage is comparatively lower, possibly due to complete consumption of silicic acid and lack of terrigenous input.
CLIMATE OF THE PAST
(2022)