Article
Multidisciplinary Sciences
Natascha Riedinger, Florian Scholz, Michelle L. Abshire, Matthias Zabel
Summary: Sedimentary records from the last glacial period in the eastern South Atlantic show evidence of continuous bottom water anoxia, leading to increased carbon burial. Geochemical data suggest that increased productivity and slowed deep water circulation were the main drivers of anoxic conditions in deep waters.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geography, Physical
Min Zeng, Harunur Rashid, Yuxin Zhou, Jerry F. McManus, Yang Wang
Summary: Previous studies have shown that millennial-scale sea-surface cooling occurred in the North Atlantic during the last glacial cycle, but few studies have examined detailed planktonic foraminiferal data in the North Atlantic Transition Zone and subpolar gyre. In this study, planktonic foraminiferal abundances, oxygen isotopes, and ice-rafted detritus counts were analyzed to reconstruct changes in surface water masses and dynamics of oceanic fronts in the North Atlantic. The results indicate that the dynamics of the surface circulation in the North Atlantic during the last glacial cycle were influenced by various factors.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Dillon J. Amaya, Alan M. Seltzer, Kristopher B. Karnauskas, Juan M. Lora, Xiyue Zhang, Pedro N. DiNezio
Summary: The Western U.S. experienced significant hydroclimatic changes during the Last Glacial Maximum (LGM), with a wetter Southwest and drier Pacific Northwest. This study examines the mechanisms behind these shifts and finds that ice sheet albedo influenced sea surface temperatures and altered large-scale atmospheric circulation, leading to changes in west coast precipitation. Importantly, the study suggests that similar hydroclimatic changes could occur today due to atmosphere-ocean feedbacks.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geography, Physical
Roberta Pini, Giulia Furlanetto, Francesca Valle, Federica Badino, Lucia Wick, Flavio S. Anselmetti, Paolo Bertuletti, Nicoletta Fusi, Marina A. Morlock, Barbara Delmonte, Sandy P. Harrison, Valter Maggi, Cesare Ravazzi
Summary: This study investigates the climate evolution between the North Atlantic and the Alps during the last glaciation. By analyzing a high-resolution record from Lake Fimon in the southern Alpine foothills, the researchers reveal the linkage between the climate changes in the Alps and the North Atlantic events, providing insights into the in-phase reactions of the British-Irish Ice Sheet, Alpine glaciers, and ecosystems to changes in the Atlantic Meridional Circulation.
QUATERNARY SCIENCE REVIEWS
(2022)
Review
Geography, Physical
Y. Zhou, J. F. McManus
Summary: Oxygen in the ocean plays essential roles in ecology and climate, indicating deep ocean ventilation and carbon storage. Previous studies disagree on the oxygen levels in the subsurface of the North Atlantic during the Last Glacial Maximum. This study uses uranium measurements in deep-sea sediments to reveal lower oxygen levels in the deep North Atlantic during the Last Glacial Maximum, with pronounced regional differences.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Jimin Yu, Delia W. Oppo, Zhangdong Jin, Matthew Lacerra, Xuan Ji, Natalie E. Umling, David C. Lund, Nick McCave, Laurie Menviel, Jun Shao, Chen Xu
Summary: Atmospheric CO2 can critically influence the global climate, but the mechanisms of carbon transfer between the oceanic and atmospheric reservoirs are poorly understood. Recent studies suggest that during the deglaciation, there was a net release of CO2 in the Atlantic sector of the Southern Ocean, contributing to the rise in atmospheric CO2. Additionally, the expansion of Antarctic Intermediate Water was found to be responsible for the rise in atmospheric CO2 during the Bolling warming event.
Article
Geosciences, Multidisciplinary
Minda Moriah Monteagudo, Jean Lynch-Stieglitz, Thomas M. Marchitto, Matthew W. Schmidt
Summary: This study reveals that the central equatorial Pacific cooled by about 2.0 degrees Celsius during the Last Glacial Maximum, contradicting previous estimates but aligning with climate models. This suggests a larger magnitude of cooling in the tropical region during the LGM, implying a higher equilibrium climate sensitivity.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Andrea Columbu, Christoph Spoetl, Jens Fohlmeister, Hsun-Ming Hu, Veronica Chiarini, John Hellstrom, Hai Cheng, Chuan-Chou Shen, Jo De Waele
Summary: This study suggests that rainfall variability in the central Mediterranean during the last deglaciation was closely linked to temperatures at high northern latitudes and influenced by strengthened westerly winds. The findings highlight the importance of high-latitude climate changes in causing rainfall variation in the Mediterranean region.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
S. Barragan-Montilla, S. Mulitza, H. J. H. Johnstone, H. Paelike
Summary: The Atlantic Meridional Overturning Circulation (AMOC) plays a significant role in the climate system by regulating oceanic heat storage. The weakening of AMOC leads to reduced ventilation and causes the heat absorbed by the oceans to mix downwards, resulting in warming of Atlantic intermediate waters. This study presents a reconstruction of bottom water temperatures in the North Atlantic over the past 46,000 years, revealing periods of intense deep water warming during AMOC decline. The findings support the hypothesis that AMOC strength determines the depth of oceanic heat storage. Evaluation: 8/10
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Frerk Poppelmeier, Aurich Jeltsch-Thommes, Joerg Lippold, Fortunat Joos, Thomas F. Stocker
Summary: According to a reassessment of proxy records and model simulations, the Atlantic meridional overturning circulation was shallow and weak during the Last Glacial Maximum, and it took time for water masses to adjust to circulation shifts during the Last Deglaciation. However, uncertainties still exist in understanding the Atlantic circulation and its response to external perturbations.
Article
Geosciences, Multidisciplinary
Qiang Wei, Yonggang Liu, Qing Yan, Tandong Yao, Miao Wang, Han Huang, Yongyun Hu
Summary: The growth of glaciers affects the local climate system and can either promote or prohibit further glacier growth. This feedback mechanism has not been included in previous glacier modeling studies of the Tibetan Plateau and its surroundings during the Last Glacial Maximum. However, this study found that when considering the feedback, the simulated volume and area of the glaciers were 20% and 10% less, respectively, compared to a standalone glacier model. The expansion of glaciers also led to changes in spatial patterns, improved model-data comparison, and had significant impacts on the winter surface temperature and precipitation distribution in the region.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Kira Homola, Arthur J. Spivack, Richard W. Murray, Robert Pockalny, Steven D'Hondt, Rebecca Robinson
Summary: This study reconstructed deep water-mass salinities in the western North Atlantic during the Last Glacial Maximum, finding that salinities during the LGM were significantly higher than modern values. This increase may be related to factors such as eustatic sea level rise, increased thermal energy, and changes in ocean circulation.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geosciences, Multidisciplinary
Asmita Banerjee, Laurence Y. Yeung, Lee T. Murray, Xin Tie, Jessica E. Tierney, Allegra N. Legrande
Summary: Ice cores and other paleotemperature proxies provide information about past surface temperatures, but little is known about high-altitude temperatures. This study uses the clumped-isotope composition of molecular oxygen in ice cores to infer that the upper troposphere was 6-9 degrees C cooler during the Last Glacial Maximum than during the late preindustrial Holocene.
Article
Geosciences, Multidisciplinary
Frerk Poppelmeier, Jeemijn Scheen, Aurich Jeltsch-Thommes, Thomas F. Stocker
Summary: The study reveals that in glacial boundary conditions, the AMOC is more sensitive to North Atlantic freshwater perturbations compared to preindustrial conditions, mainly due to the closed Bering Strait leading to faster accumulation of freshwater in the North Atlantic. In addition, simulations with improved boundary conditions show that the evolution of the AMOC is more closely aligned with proxy reconstructions, suggesting a weaker and possibly shallower AMOC during the Last Glacial Maximum.
CLIMATE OF THE PAST
(2021)
Article
Geosciences, Multidisciplinary
Ming Zhang, Yonggang Liu, Jiang Zhu, Zhuoqun Wang, Zhengyu Liu
Summary: In this study, we investigated the changes in climate and Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum if there were no dust. Model simulations showed that the removal of dust resulted in a global cooling and weakening of AMOC. This cooling effect was opposite to that observed during the mid-Holocene and was amplified by a positive feedback between sea ice and AMOC.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
D. J. Bertassoli, C. Haeggi, C. M. Chiessi, E. Schefuss, J. Hefter, T. K. Akabane, A. O. Sawakuchi
Summary: This study investigates the distribution of glycerol dialkyl glycerol tetraether (GDGT) and n-alkane isotopes in soils and sediments from the Amazon River Basin, and examines the impact of sources and transport processes on their distribution.
Article
Geography, Physical
J. Maksic, I. M. Venancio, M. H. Shimizu, C. M. Chiessi, P. Piacsek, G. Sampaio, Francisco W. Cruz, F. F. Alexandre
Summary: The Last Glacial Maximum (LGM) was characterized by atmospheric cooling, showing contrasts to the current warming climate. Research indicates that in the Western and Central Amazon forest regions, the biomes remained largely unchanged during the LGM due to negative temperature anomalies, while in the Eastern portion, a shift from tropical evergreen forest to tropical seasonal forest was observed. Future warming scenarios suggest a potential expansion of Savanna/Cerrado and a reduction of tropical seasonal forest and Caatinga in Brazil, impacting biodiversity and regional climate.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Igor M. Venancio, Rodrigo A. Nascimento, Thiago P. Santos, Andre L. Belem, Douglas O. Lessa, Ralf Tiedemann, Cristiano M. Chiessi, Stefan Mulitza, Ana Luiza S. Albuquerque
Summary: Tropical precipitation patterns are likely to be altered by future climate change, causing major socioeconomic consequences for populations reliant on water availability for survival. Understanding the response of tropical precipitation to abrupt climate change, as evidenced by past events such as the Dansgaard-Oeschger cycles, is crucial for improving future projections and adaptation policies. This study presents a paleoceanographic reconstruction of northeastern Brazil, revealing changes in rainfall patterns during abrupt climate change events.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Alicia Hou, Andre Bahr, Cristiano M. Chiessi, Andrea Jaeschke, Ana Luiza S. Albuquerque, Jorg Pross, Andreas Koutsodendris, Oliver Friedrich
Summary: This study found that hydroclimate change in the coastal zone is primarily modulated by obliquity forcing rather than the South American Monsoon System. High-latitude forcing in the Northern Hemisphere may have increased the overturning circulation and led to reduced moisture advection to the coastal zone.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2022)
Article
Geography, Physical
Jaqueline Q. Ferreira, Cristiano M. Chiessi, Marina Hirota, Rafael S. Oliveira, Matthias Prange, Christoph Haggi, Stefano Crivellari, Sri D. Nandini-Weiss, Dailson J. Bertassoli, Marilia C. Campos, Stefan Mulitza, Ana Luiza S. Albuquerque, Andre Bahr, Enno Schefuss
Summary: By investigating sediment records from eastern tropical South America, it was found that obliquity has a significant influence on the expansion and contraction of tree and grass cover in tropical landscapes. The length of the dry season was identified as a crucial factor in controlling tree cover in these regions.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Thiago P. Santos, Marilia H. Shimizu, Rodrigo A. Nascimento, Igor M. Venancio, Marilia C. Campos, Rodrigo C. Portilho-Ramos, Joao M. Ballalai, Douglas O. Lessa, Stefano Crivellari, Renata H. Nagai, Cristiano M. Chiessi, Henning Kuhnert, Andre Bahr, Ana Luiza S. Albuquerque
Summary: This study examines the sea surface temperature evolution of the Brazilian margin from the Last Glacial Maximum (LGM) to the late Holocene. The research reveals that the input of meltwater from retreating ice sheets and increasing atmospheric CO2 triggered the warming after the LGM. They also identified abrupt cooling events during periods of fast sea-level rise. These findings have important implications for understanding past and future climate changes in the region.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geosciences, Multidisciplinary
Natalia Garcia Chapori, Cecilia Laprida, Daniel Lo Prete, Cristiano M. Chiessi, Christoph Mayr, Roberto A. Violante
Summary: Although our knowledge about the long-term past changes in the circulation of the western South Atlantic is fragmented and sparse, analysis of selected palaeoceanographic records reveals substantial changes in the Brazil-Malvinas Confluence region during the Holocene. The Southern Atlantic Meridional Overturning Circulation strengthened since the Mid-Holocene, while the Atlantic Meridional Overturning Circulation weakened towards the preindustrial times.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2022)
Article
Geography, Physical
N. S. Pereira, L. J. Clarke, C. M. Chiessi, K. H. Kilbourne, S. Crivellari, F. W. Cruz, J. L. P. S. Campos, T-L Yu, C-C Shen, R. K. P. Kikuchi, B. R. Pinheiro, G. O. Longo, A. N. Sial, T. Felis
Summary: The study focused on the isotopic records of a Siderastrea stellata coral from northeastern Brazil, showing that long-term trends are primarily driven by hydrological changes at the sea surface. It also presented the first reconstruction of seawater delta O-18 changes in the western tropical South Atlantic, revealing a prominent freshening trend during the mid to late 20th century.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Multidisciplinary Sciences
Lars Max, Dirk Nuernberg, Cristiano M. Chiessi, Marlene M. Lenz, Stefan Mulitza
Summary: This study provides solid evidence for the rapid subsurface ocean warming preceding Heinrich Events in the subpolar Atlantic. The accumulation of ocean heat near the critical depth is identified as the trigger for the melting of marine-terminating portions of the Laurentide Ice Sheet. The study also suggests that weaker ocean circulation in the future may lead to accelerated interior-ocean warming, which is critical for the stability of modern Arctic glaciers and the freshwater budget of the North Atlantic.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Layla Creac'h, Taryn L. Noble, Zanna Chase, Bruce L. A. Charlier, Ashley T. Townsend, Habacuc Perez-Tribouillier, Christian Dietz
Summary: Determining past changes in ocean circulation on the Antarctic margin is important, but the current proxy methods are limited. This study evaluates the use of neodymium isotopes as a proxy for ocean circulation along the Wilkes Land continental rise. The results show the potential of seawater neodymium isotopes as water mass signatures, but further research is needed to develop reliable proxies for Antarctic water masses.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geography, Physical
Andrea K. Kern, Thomas Kenji Akabane, Jaqueline Q. Ferreira, Cristiano M. Chiessi, Debra A. Willard, Fabricio Ferreira, Allan Oliveira Sanders, Cleverson G. Silva, Catherine Rigsby, Francisco W. Cruz, Gary S. Dwyer, Sherilyn C. Fritz, Paul A. Baker
Summary: This study investigates the vegetation history of the Amazon basin over the past 18 million years. The research suggests that the Amazonian lowlands were mainly composed of tropical rainforests, warm-temperate rainforests, and tropical seasonal forests, and their composition correlated with global climate cycles. The study also highlights the sensitivity of tropical rainforests to changes in CO2, temperature, and moisture availability.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geography, Physical
Alisson K. Martins, Karlos G. D. Kochhann, Cristiano M. Chiessi, Thorsten Bauersachs, Tamires N. Zardin, Marilia C. Campos, Guilherme Krahl, Lais V. de Souza, Stefano Crivellari, Andre Bahr, Henning Kuhnert, Lorenz Schwark, Gerson Fauth
Summary: This study examines the effects of past collapses or weakening of the Atlantic Meridional Overturning Circulation (AMOC) on different components of the climate system. By analyzing sediment data from the South Atlantic Ocean, the study finds that periods of AMOC declines were associated with wetter conditions over eastern tropical South America and higher sea surface temperatures in the western South Atlantic Ocean. Furthermore, it is found that intense runoff during one of these periods led to increased nutrient transfer to the ocean, resulting in higher primary productivity.
QUATERNARY INTERNATIONAL
(2023)
Article
Multidisciplinary Sciences
Germain Bayon, Martin Patriat, Yves Godderis, Anne Trinquier, Patrick De Deckker, Denise K. Kulhanek, Ann Holbourn, Yair Rosenthal
Summary: Arc-continent collision in Southeast Asia during the Neogene may have driven global cooling through chemical weathering of ophiolites resulting in atmospheric CO2 removal. Yet, little is known about the cause-and-effect relationships between erosion and the long-term evolution of tectonics and climate in this region. Here, we present an 8-million-year record of seawater chemistry and sediment provenance from the eastern Indian Ocean, near the outflow of Indonesian Throughflow waters.
Article
Geosciences, Multidisciplinary
A. Bahr, A. Jaeschke, A. Hou, K. Meier, C. M. Chiessi, A. L. Spadano Albuquerque, J. Rethemeyer, O. Friedrich
Summary: The accurate reconstruction of sea-surface temperatures is crucial for understanding the global climate system. In this study, we investigate the fidelity of SST reconstructions for the western tropical South Atlantic during Marine Isotope Stages 6-5. Our results show that previous SST estimates based on Mg/Ca ratios of planktic foraminifera are supported by alkenone-based temperature estimates, suggesting a warm-water anomaly during MIS 6. However, TEX86-derived temperatures are colder, potentially due to the vertical migration of the TEX86 producers.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Stefan Mulitza, Torsten Bickert, Helen C. Bostock, Cristiano M. Chiessi, Barbara Donner, Aline Govin, Naomi Harada, Enqing Huang, Heather Johnstone, Henning Kuhnert, Michael Langner, Frank Lamy, Lester Lembke-Jene, Lorraine Lisiecki, Jean Lynch-Stieglitz, Lars Max, Mahyar Mohtadi, Gesine Mollenhauer, Juan Muglia, Dirk Nuernberg, Andre Paul, Carsten Ruehlemann, Janne Repschlaeger, Rajeev Saraswat, Andreas Schmittner, Elisabeth L. Sikes, Robert F. Spielhagen, Ralf Tiedemann
Summary: This database presents a global atlas of downcore foraminiferal oxygen and carbon isotope ratios, providing valuable data for paleoceanographic analyses and teaching marine stratigraphy. It includes a large number of stable isotope records and radiocarbon ages from sediment cores.
EARTH SYSTEM SCIENCE DATA
(2022)