Article
Geochemistry & Geophysics
J. T. Middleton, A. Paytan, M. Auro, M. A. Saito, T. J. Horner
Summary: The isotope composition of barium (Ba) in barite (BaSO4) is a powerful tool for tracing the cycles of pelagic Ba, carbon, and sulfur. This study analyzed the Ba isotope composition of porewaters and co-located BaSO4 in sediments from the Equatorial Pacific, and conducted laboratory experiments to assess the rates of Ba isotope alteration. The results suggest that ion exchange occurs in Equatorial Pacific sediments, and this process drives the observed Ba isotope offsets between pelagic BaSO4 and porewaters.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Review
Astronomy & Astrophysics
Yarrow Axford, Anne de Vernal, Erich C. Osterberg
Summary: Higher boreal summer insolation in the early to middle Holocene led to significant warming across the Arctic. Geological data from this warm period show that Greenland experienced summers 3 to 5 degrees C warmer than the mid-twentieth century, with dramatic consequences for glaciers, ice sheets, ocean circulation, and flora and fauna.
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES, VOL 49, 2021
(2021)
Article
Multidisciplinary Sciences
Nina Davtian, Edouard Bard
Summary: The last glacial cycle provides an opportunity to investigate large changes in the Atlantic Meridional Overturning Circulation (AMOC) beyond the small fluctuations evidenced from direct measurements. Temperature records from Greenland and the North Atlantic show abrupt variability known as Dansgaard-Oeschger (DO) events, which are associated with abrupt changes of the AMOC. The thermal bipolar seesaw concept explains the asynchronous temperature changes between the hemispheres. The role of the thermal bipolar seesaw in the temperature variability during DO cooling events with Heinrich (H) events is more complex than a simple flip-flop between two climate states linked to a tipping point threshold.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Samuel Z. Mark, Mark B. Abbott, Donald T. Rodbell, Christopher M. Moy
Summary: This study investigates the laminated sedimentary sequence of Laguna Pallcacocha in Ecuador and improves the chronology using Pb-210 and C-14 dating methods. By using X-ray Fluorescence and principal component analysis, the researchers reconstruct the flood history and identify patterns of El Nino activity during the Holocene. The results suggest that El Nino variability in the region is influenced by both long-term changes in tropical insolation and latitudinal displacement of the ITCZ and ocean-atmospheric variabilities in other ocean basins.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Environmental Sciences
Kevin J. Erratt, Irena F. Creed, Elizabeth J. Favot, John P. Smol, Rolf D. Vinebrooke, David A. Lobb, Charles G. Trick
Summary: The global rise of cyanobacterial blooms necessitates the development of tools for managing cyanobacteria-prone water bodies. This study compares spectral inferences using VNIRS with molecular quantification using qPCR to reconstruct cyanobacterial abundance in sediments. The findings suggest that VNIRS is suitable for reconstructing recent cyanobacterial prevalence, but further refinement is needed in some cases.
JOURNAL OF ENVIRONMENTAL MANAGEMENT
(2023)
Article
Geography, Physical
Alicja Bonk, Daniela Mueller, Arne Ramisch, Mateusz A. Kramkowski, Agnieszka M. Noryskiewicz, Ilona Sekudewicz, Michal Gasiorowski, Katarzyna Luberda-Durnas, Michal Slowinski, Markus Schwab, Rik Tjallingii, Achim Brauer, Miroslaw Biaszkiewicz
Summary: The study presents a detailed sediment record of Lake Gosciaz in Central Poland, which serves as a comprehensive climate archive of the Late Glacial and the Holocene in Central Europe. The research utilized microfacies analyses, mu XRF core scanning, and varve chronology to identify lithozones and depositional changes. The findings reveal significant shifts in geochemistry during the Holocene and Late Glacial, including increased calcite precipitation and primary productivity around 7940 varve yr BP, possibly influenced by local hydrological changes.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geosciences, Multidisciplinary
Qi Zhang, Xingqi Liu, Shengnan Feng
Summary: The varved sediments of Kusai Lake on the northern Tibetan Plateau provide valuable information for annual-resolution climate reconstruction. The study found that the summer flux was generally higher than the winter flux in the last 2280 years, and the seasonal flux of the sediments was influenced by solar activity, Pacific Decadal Oscillation, and Quasi-biennial Oscillation.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Radiology, Nuclear Medicine & Medical Imaging
Florian Alexander Huber, Fabio Becce, Spyridon Gkoumas, Thomas Thuring, Sylvain Steinmetz, Igor Letovanec, Roman Guggenberger
Summary: The study aimed to test the capability of spectral photon-counting radiography (SPCR) in identifying and distinguishing different crystals associated with arthropathies, and validated the findings in a gouty human toe ex vivo. Significant differences in attenuation and Z(eff) values were found for different concentrations and materials in both SPCR and DECT. SPCR is able to identify and differentiate various crystals related to arthropathies with comparable diagnostic accuracy to DECT.
INVESTIGATIVE RADIOLOGY
(2021)
Article
Environmental Sciences
Kirklyn B. Davidson, Baillie E. J. Holmes, Ian S. Spooner, Dewey W. Dunnington, Tony R. Walker, Craig B. Lake, Chih-Chieh Su
Summary: The paleolimnological method was used to study a contaminated sediment stabilization basin in Nova Scotia, Canada and found that there was no distinct spatial trend in metal concentrations, high and variable concentrations of Cu and Zn in contaminated sediment, and high sedimentation rate. Temporal trends indicated significantly higher concentrations of Zn and Cu in top sediment samples.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2021)
Review
Ecology
Matthew P. P. Duda, Kathryn E. E. Hargan, Neal Michelutti, Jules M. M. Blais, Christopher Grooms, H. Grant Gilchrist, Mark L. L. Mallory, Gregory J. J. Robertson, John P. P. Smol
Summary: The lack of long-term monitoring data for many wildlife populations poses a challenge in setting conservation goals, leading to the development of techniques using sedimentary archives to study long-term population dynamics. By focusing on bird-related studies, various paleolimnological proxies have been successfully used to reconstruct past colony sizes, addressing important questions in conservation biology such as population dynamics, responses to climate change, and reactions to human intrusion.
FRONTIERS IN ECOLOGY AND EVOLUTION
(2021)
Article
Environmental Sciences
Alexandre Baud, John P. Smol, Carsten Meyer-Jacob, Michael Paterson, Pierre Francus, Irene Gregory-Eaves
Summary: Acidification and eutrophication are important stressors affecting water bodies globally. The influence of these stressors on metal accumulation in lake sediment is unclear. Through research and long-term monitoring, we found that eutrophication leads to higher lead accumulation in lake sediment, while acidification leads to lower lead accumulation.
ENVIRONMENTAL POLLUTION
(2023)
Article
Geography, Physical
Danielle Ward, Andrea Brunelle, Brenda B. Bowen
Summary: This study builds on previous paleoclimatic reconstruction and uses various proxies to examine the role of moisture in the migration of the Fremont people in the 12th century. The analysis of elemental ratios, weathering indices, and pollen data from sediment cores confirms the effectiveness of these proxies in representing precipitation fluctuation. Moreover, XRF analysis of the cores validates the existing chronology by identifying a sudden depositional event linked to a volcanic eruption. The findings suggest that the Fremont entered the canyon during a period of increased precipitation, but left due to drought conditions in the later years.
Article
Geochemistry & Geophysics
Edouard G. H. Philippe, Guillaume St-Onge, Jean-Pierre Valet, Pierre-Marc Godbout, Ramon Egli, Pierre Francus, Martin Roy
Summary: The high sedimentation rate sediments' natural remanent magnetization (NRM) provides valuable information about the paleomagnetic secular variation of the Earth's magnetic field and can be used for stratigraphy. However, the acquisition of NRM is dependent on the specific conditions of the depositional environment. Varved sediments, in addition to providing an accurate annual chronology, also reflect significant annual sedimentary changes.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Environmental Sciences
Xiaoqing Liu, Katrin Wendt-Potthoff, Johannes A. C. Barth, Kurt Friese
Summary: This study investigates the degradation of organic matter in freshwater sediments and its impact on biogeochemical dynamics and carbon burial. The study finds that degradation of organic matter is influenced by the types and sources of organic matter, leading to changes in stable isotope ratios. The results suggest that the lability of algae-derived organic matter can affect carbon burial estimation and obscure paleoenvironmental information derived from isotopic proxies.
Article
Environmental Sciences
Kejia Ji, Erlei Zhu, Guoqiang Chu, Marco A. Aquino-Lopez, Juzhi Hou
Summary: Lake sediments on the Tibetan Plateau serve as important natural archives for studying past climate and environmental changes. A varve chronology from Jiang Co spanning the last 2000 years reveals centennial-scale fluctuations in precipitation, providing valuable insights into past climate and environment changes in the region. The study demonstrates the utility of analyzing varve thickness as a proxy for summer precipitation amount in the area.
JOURNAL OF PALEOLIMNOLOGY
(2021)