Article
Geochemistry & Geophysics
Keiran A. Swart, Sergey Oleynik, Alfredo Martinez-Garcia, Gerald H. Haug, Daniel M. Sigman
Summary: By using foraminifera-bound organic matter (FBOM) delta C-13 as a potential proxy for dissolved CO2 concentration, researchers have achieved higher precision testing with new protocols and instruments. They found an inverse correlation between FBOM-delta C-13 and surface water [CO2(aq)], indicating the potential for FBOM-delta C-13 to serve as a paleoceanographic proxy for atmospheric pCO2.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Arbia Jouini, Guillaume Paris, Guillaume Caro, Annachiara Bartolini, Sivia Gardin
Summary: The Mesozoic-Cenozoic transition is a period of significant disruptions in the biogeochemical cycle, with the Cretaceous-Paleogene boundary (K-Pg) crisis being the most notable one. This crisis resulted in the extinction of marine calcifiers due to the increase in atmospheric CO2 concentration and ocean acidification triggered by the Chicxulub Impact and Deccan volcanism. The Ca isotope composition of carbonate minerals can provide insights into these environmental changes. The study presents new records of planktonic and benthic foraminiferal & delta;44/40Ca, & delta;18O, & delta;13C, and Sr/Ca across the K-Pg transition, indicating rapid shifts in & delta;44/40Ca that are likely caused by changes in precipitation rates rather than global disequilibrium in the oceans' Ca budget.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Yu Zhang, Shiyun Yu, Dillon J. Amaya, Yu Kosaka, Sarah M. Larson, Xudong Wang, Jun-Chao Yang, Malte F. Stuecker, Shang-Ping Xie, Arthur J. Miller, Xiaopei Lin
Summary: Investigating the North PMM and South PMM through a mechanically decoupled climate model simulation revealed new insights into their associated atmospheric forcing and response processes.
JOURNAL OF CLIMATE
(2021)
Article
Geochemistry & Geophysics
Brian A. Haley, Yingzhe Wu, Jesse M. Muratli, Chandranath Basak, Leopoldo D. Pena, Steven L. Goldstein
Summary: Data on dissolved rare earth elements and neodymium isotopes in the Eastern Equatorial Pacific were compared with other data to evaluate current geochemical theories, revealing inconsistencies and suggesting non-conservative components may be at play in the water column.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Wei Shen, Shuqing Qiao, Rongtao Sun, Zhoutian He, Bin Wu, Lina Jin, Liang Chen, Zhengxin Yin, Chendong Ge, Xuefa Shi, Jie Sheng
Summary: This study focuses on the distribution and environmental implications of foraminifera in surface sediments in the equatorial western Indian Ocean. The planktonic foraminifera are mainly influenced by depth-controlled dissolution rate of carbonate, temperature, and salinity, while the benthic foraminifera are related to oxygen content and water mass. The results reveal differences in productivity between the western and eastern regions of the Central Indian Ridge.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
Zhimin Jian, Jimin Yu, Yue Wang, Haowen Dang, Minhan Dai, Chen Li, Xuan Ji, Xingxing Wang, Yue Chen
Summary: The study finds that the oceanic dynamics in the equatorial Pacific during the last deglaciation to early Holocene led to different exchange of atmospheric CO2, resulting in the Western equatorial Pacific becoming a sink for CO2.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Qiang Ma, Jianing Wang, Fan Wang, Yilong Lyu, Zhixiang Zhang
Summary: The Pacific Decadal Oscillation (PDO) influences the El Nino-Southern Oscillation and can modulate the equatorial intermediate currents. This modulation is achieved through the propagation of reflected Kelvin-to-Rossby waves triggered by anomalous westerly wind.
GEOPHYSICAL RESEARCH LETTERS
(2022)
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
Michael Fuhr, Georgi Laukert, Yang Yu, Dirk Nuernberg, Martin Frank
Summary: The study utilizes dissolved neodymium isotopes to track the formation and mixing of water masses in the North Pacific, revealing significant contrasts in neodymium isotope signatures between equatorial surface waters and deep waters, influenced by weathering inputs from Papua-New-Guinea. In the deep-water region, neodymium isotopes are not effective quantitative tracers of water mass mixing.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Ruixue Wang, Thomas J. Williams, Claus-Dieter Hillenbrand, Werner Ehrmann, Christina S. Larkin, Alec M. Hutchings, Alexander M. Piotrowski
Summary: Neodymium isotopes have been used to trace water mass source in the ocean, but the cycling of Nd is not fully understood. This study investigates the potential boundary processes near the seawater-sediment interface in Antarctica, showing the occurrence of a process similar to boundary exchange in porewaters. The study suggests that partial dissolution of radiogenic detrital particles and re-scavenging play a role in modifying the Nd isotopic ratios in porewaters. Benthic flux is found to be lower on the Antarctic margin compared to other studies, and it slightly increases along the Antarctic Peninsula due to organic matter degradation.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Oceanography
Ryoung Ah Kim, Kyung Eun Lee, Tae Wook Ko
Summary: This study investigated the seasonal and vertical distributions of planktonic foraminiferal species in the western tropical Pacific Ocean. The results showed an increase in the diversity and abundance of planktonic foraminifera in summer. The habitat depth of planktonic foraminifera varied with species, with different species inhabiting the surface mixed layer, uppermost thermocline, upper thermocline, and lower thermocline.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2023)
Article
Multidisciplinary Sciences
Sarah M. Kang, Yechul Shin, Hanjun Kim, Shang-Ping Xie, Shineng Hu
Summary: Most state-of-art models predict a weakening of the Walker circulation and a reduced east-west temperature gradient in the equatorial Pacific under global warming, but the causes of this projection are still unknown. Through a series of model experiments, this study decomposes the global warming response into the contributions from direct CO2 forcing, sea ice changes, and regional ocean heat uptake. The results show that the CO2 forcing dominates the slowdown of the Walker circulation, while Antarctic sea ice changes and local ocean heat release are the main drivers for the reduced temperature gradient in the equatorial Pacific.
Article
Multidisciplinary Sciences
Thomas J. Browning, Mak A. Saito, Shungudzemwoyo P. Garaba, Xuechao Wang, Eric P. Achterberg, C. Mark Moore, Anja Engel, Matthew R. Mcllvin, Dawn Moran, Daniela Voss, Oliver Zielinski, Alessandro Tagliabue
Summary: The impact of climate change on ocean net primary productivity is highly uncertain, with phytoplankton nutrient limitation in the low-latitude Pacific Ocean playing a crucial role, but poorly constrained by observations. We found that changes in physical forcing resulted in consistent fluctuations in the strength of equatorial Pacific iron limitation through El Nino/Southern Oscillation (ENSO) cycles, which were overestimated by a state-of-the-art climate model. Our assessment provides a powerful approach for evaluating the realism of model projections of net primary productivity to climate changes.
Article
Geosciences, Multidisciplinary
Ke Huang, Dongxiao Wang, Gengxin Chen, Motoki Nagura, Weiqing Han, Michael J. McPhaden, Ming Feng, Ju Chen, Ying Wu, Xiaolin Zhang, Yuanlong Li, Qiang Xie, Weiqiang Wang, Feng Zhou
Summary: The anomalously strong westward Equatorial Undercurrent developed in 2016 and 1998 in the Indian Ocean coinciding with extreme Indian Ocean Dipole and El Nino events. The constructive interactions between directly wind-forced and boundary-reflected waves play a crucial role in driving the interannual variability of the Indian Ocean wEUC.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Madison G. Shankle, Natalie J. Burls, Alexey V. Fedorov, Matthew D. Thomas, Wei Liu, Donald E. Penman, Heather L. Ford, Peter H. Jacobs, Noah J. Planavsky, Pincelli M. Hull
Summary: Recent studies have shown that in the early Pliocene/late Miocene period, the circulation regime in the equatorial Pacific was significantly different from modern times, leading to the influx of older, more acidic, and more nutrient-rich water into the region, resulting in enhanced productivity in the east Pacific despite weaker wind-driven upwelling.
Correction
Multidisciplinary Sciences
H. J. L. van der Lubbe, I. R. Hall, S. Barker, S. R. Hemming, T. F. Baars, A. Starr, J. Just, B. C. Backeberg, J. C. A. Joordens
Article
Multidisciplinary Sciences
Michael E. Weber, Ian Bailey, Sidney R. Hemming, Yasmina M. Martos, Brendan T. Reilly, Thomas A. Ronge, Stefanie Brachfeld, Trevor Williams, Maureen Raymo, Simon T. Belt, Lukas Smik, Hendrik Vogel, Victoria L. Peck, Linda Armbrecht, Alix Cage, Fabricio G. Cardillo, Zhiheng Du, Gerson Fauth, Christopher J. Fogwill, Marga Garcia, Marlo Garnsworthy, Anna Glueder, Michelle Guitard, Marcus Gutjahr, Ivan Hernandez-Almeida, Frida S. Hoem, Ji-Hwan Hwang, Mutsumi Iizuka, Yuji Kato, Bridget Kenlee, Suzanne OConnell, Lara F. Perez, Osamu Seki, Lee Stevens, Lisa Tauxe, Shubham Tripathi, Jonathan Warnock, Xufeng Zheng
Summary: The field of Southern Ocean paleoceanography is vital for understanding the development of iron fertilization and oceanic productivity during Pleistocene ice-ages and their impact on the carbon cycle. A high-resolution record of dust deposition and ocean productivity in the Antarctic Zone has revealed significant changes over the past 1.5 million years, with increased dust deposition during glacials and higher biogenic silica deposition during interglacials. The study also suggests more severe glaciations and changes in ocean productivity over the past 0.9 million years.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
Gabriela Torre, Diego Gaiero, Renata Coppo, Nicolas J. Cosentino, Steven L. Goldstein, Francois De Vleeschouwer, Gael Le Roux, Louise Bolge, Yael Kiro, Andre Oliveira Sawakuchi
Summary: The study investigates the provenance of dust in the Pampean loess in central Argentina, providing insight into the paleo-atmospheric circulation in the Southern Hemisphere. The isotopic analysis reveals that the dust mainly originates from the southern Altiplano and southern Puna, and there is a similarity between the paleo-dust and modern dust sources. The study also suggests that changes in atmospheric transport efficiency may better explain dust flux variations in the loess over glacial/interglacial periods.
EARTH-SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Kai Tawil-Morsink, Jacqueline Austermann, Blake Dyer, Oana A. Dumitru, William F. Precht, Miranda Cashman, Steven L. Goldstein, Maureen E. Raymo
Summary: This study reconstructs the relative sea level (RSL) during Marine Isotope Stage 5a (MIS 5a) using fossil coral elevations and provides a new estimate for the global mean sea level (GMSL) during this period. The analysis suggests that GMSL most likely peaked at -22.3 meters relative to the present, indicating a sequentially decreasing trend in GMSL during the precessional insolation peaks of MIS 5e, 5c, and 5a, which corresponds to increased ice sheet growth and cooling into the ice age following the peak interglacial MIS 5e.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geochemistry & Geophysics
Yingzhe Wu, Leopoldo D. Pena, Robert F. Anderson, Alison E. Hartman, Louise L. Bolge, Chandranath Basak, Joohee Kim, Micha J. A. Rijkenberg, Hein J. W. De Baar, Steven L. Goldstein
Summary: The global overturning ocean circulation is crucial for global climate and can be traced using neodymium (Nd) isotopes. However, the value of Nd isotopes as a circulation tracer has been questioned due to various processes that can modify seawater Nd isotope ratios. This study investigates the integrity of Nd isotopes as an ocean circulation tracer in the Southwest Atlantic and confirms their potential for reconstructing past ocean circulation changes.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geography, Physical
Pietro Bazzicalupo, Marie-Alexandrine Sicre, Helena Checa, Patrizia Maiorano, Giulia Margaritelli, Vincent Klein, Leopoldo David Pena, Isabel Cacho, Jaime Frigola, Sergio Bonomo, Antonio Cascella, Fabrizio Lirer
Summary: A multiproxy study using calcareous plankton assemblages, terrestrial and marine biomarkers was conducted on a sediment core from the South Adriatic Sea. The study aimed to investigate climate variability in the Eastern Mediterranean during the last deglaciation, specifically between 20 and 11 ka BP. The results show changes in moisture availability and ice melting delivery during the Heinrich Stadial 1 period. Additionally, the study finds a correlation between temperature variations in the South Adriatic Sea and the Greenland ice core oxygen isotope record, indicating the climatic response of the South Adriatic Sea to global climate variations.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Environmental Sciences
Cristina Romera-Castillo, Arturo Lucas, Rebeca Mallenco-Fornies, Marina Briones-Rizo, Eva Calvo, Carles Pelejero
Summary: Ocean acidification and plastic pollution are escalating threats to global societies and ecosystems. Laboratory experiments show that abiotic plastic degradation results in a decrease in seawater pH, particularly in aged plastics. Solar radiation enhances the pH decrease, likely due to the release of organic acids and the production of CO2. Plastic leaching could lead to a seawater pH decrease up to 0.5 units in coastal areas, comparable to the projected decrease by the end of the twenty-first century.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Geography, Physical
J. L. Bernal-Wormull, A. Moreno, M. Bartolome, M. Arriolabengoa, C. Perez-Mejias, E. Iriarte, C. Osacar, C. Spotl, H. Stoll, I. Cacho, R. L. Edwards, H. Cheng
Summary: This study utilized stalagmite samples from Mendukilo Cave to investigate the hydroclimate changes in the northern part of Iberia. Carbon isotopes revealed millennial-scale shifts in response to hydroclimate changes, while oxygen isotopes showed variations correlated with North Atlantic events. The findings indicated a delay in the onset of humid conditions in the early Holocene and a subsequent trend towards drier and colder conditions between 6.0 and 2.5 kyr BP. This high-resolution speleothem record demonstrated the complex connection between the North Atlantic and Western Europe during the last millennia and the regional heterogeneity of Iberia's hydroclimate.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Sidney R. Hemming, Tanzhuo Liu, Paul Northrup, Sarah Nicholas, E. Troy Rasbury, Heng Chen, Alice Warden, Amanda Chen, Ruipeng Li, Ryan Tappero, Stephen E. Cox, Jenna Everard, Silu Wang, Michael Deluca, Benjamin Bostick, Alexander N. Halliday
Summary: The K/Ar chronology of glauconite pellets, a method used to directly date marine sedimentary deposits, is improved by using synchrotron radiation to characterize individual pellets and measure the argon and potassium. The results show that the radiogenic argon concentration underestimates the values for individual visually mature pellets, and the determined K/Ar age is 6% older than the reference value and in agreement with constraints from U-Pb dating.
Article
Archaeology
S. Valenzuela-Lamas, M. Diaz-Zorita Bonilla, S. Albizuri, L. D. Pena, D. Bosch, M. E. Subira, F. J. Lopez-Cachero
Summary: The study conducted on equid teeth from Bronze and Early Iron Age Can Roqueta using multi-isotopic analysis suggests that these animals originated from diverse locations and had well-managed diets. The enriched oxygen and carbon isotopic ratios in equid teeth compared to other taxa at the same site indicate that they may have consumed water from troughs, leading to isotopic enrichment similar to that of a lake effect. This is the most comprehensive study on equid mobility in Iberia to date.
JOURNAL OF ARCHAEOLOGICAL SCIENCE-REPORTS
(2023)
Article
Multidisciplinary Sciences
Hongrui Zhang, Yongsong Huang, Reto Wijker, Isabel Cacho, Judit Torner, Madeleine Santos, Oliver Kost, Bingbing Wei, Heather Stoll
Summary: The high-resolution paleoclimate records on the Iberian Margin are important for studying abrupt climate events. Previous studies suggested a correlation between surface cooling and water freshening, but recent data indicate that the high concentration of a specific alkenone is not caused by decreased salinity, but by a decrease in sea surface temperature. Additionally, surface freshening does not always trigger cooling during millennial climate changes, sometimes occurring in the middle of cooling events and potentially amplifying temperature decrease.
NATURE COMMUNICATIONS
(2023)
Article
Geochemistry & Geophysics
Yue Cai, Sara Mana, Stephen E. Cox, Catherine C. Beck, Craig Feibel, Jean Hanley, Tanzhuo Liu, Louise Bolge, Sidney Hemming, Steven L. Goldstein
Summary: There is a consensus that volcanism along the East African Rift System (EARS) is related to plume activities. The Turkana Basin has a unique lithospheric mantle which provides valuable insights into plume-related volcanism. Different time periods in the Turkana Basin exhibit distinct geochemical and isotopic signatures, suggesting variations in the structure and evolution of the plume.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Ecology
Thibauld M. Bejard, Andres S. Rigual-Hernandez, Jose A. Flores, Javier P. Tarruella, Xavier Durrieu de Madron, Isabel Cacho, Neghar Haghipour, Aidan Hunter, Francisco J. Sierro
Summary: This study investigates the calcification response of planktic foraminifera in the northwestern Mediterranean Sea over different time scales. The results show different seasonal calcification patterns across species and indicate that environmental factors such as temperature and seawater carbonate parameters have species-specific effects on calcification. Furthermore, the study finds a decrease in planktic foraminifera calcification in the western Mediterranean since the late Holocene, including the industrial era, which is likely associated with ongoing ocean acidification and regional sea surface temperature trends.
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)