Free oxygen represents an essential basis for the evolution of complex life forms on a habitable Earth. The isotope composition of redox-sensitive trace elements such as tungsten (W) can possibly trace the earliest rise of oceanic oxygen in Earth's history. However, the impact of redox changes on the W isotope composition of seawater is still unknown. Here, we report highly variable W isotope compositions in the water column of a redox-stratified basin (δW between +0.347 and +0.810 ‰) that contrast with the homogenous W isotope composition of the open ocean (refined δW of +0.543 ± 0.046 ‰). Consistent with experimental studies, the preferential scavenging of isotopically light W by Mn-oxides increases the δW of surrounding seawater, whereas the redissolution of Mn-oxides causes decreasing seawater δW. Overall, the distinctly heavy stable W isotopic signature of open ocean seawater mirrors predominantly fully oxic conditions in modern oceans. We expect, however, that the redox evolution from anoxic to hypoxic and finally oxic marine conditions in early Earth's history would have continuously increased the seawater δW. Stable W isotope compositions of chemical sediments that potentially preserve changing seawater W isotope signatures might therefore reflect global changes in marine redox conditions.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106329 | PMC |
| http://dx.doi.org/10.1073/pnas.2023544118 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Nutrient distribution and nitrate processing in a mangrove tidal creek affected by submarine groundwater discharge (SGD).
Mar Pollut Bull
January 2025
State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China.
Investigations of the spatial-temporal variations of nutrients within mangrove coastal zones are essential for assessing the environmental status of an aquatic ecosystems. However, major processes controlling nitrate cycle along the submarine groundwater discharge (SGD) pathway from the mangrove areas to adjacent tidal creek remain underexplored. A time series measurement over a 25 h tidal cycle was conducted in Qinglan Bay tidal creek (Hainan Island, China).
View Article and Find Full Text PDFHighly Efficient Compositional and Compound Specific Isotopic Analysis of Volatile Primary Amines and Ammonia in the Murchison Meteorite Using SPME On-Fiber Derivatization: Optimization for Bennu Sample Analyses.
Rapid Commun Mass Spectrom
April 2025
Solar System Exploration Division, NASA Goddard Space Center, Greenbelt, Maryland, USA.
Rationale: Extraterrestrial amines and ammonia are critical ingredients for the formation of astrobiologically important compounds such as amino acids and nucleobases. However, conventional methods for analyzing the composition and isotopic ratios of volatile amines suffer from lengthy derivatization and purification procedures, high sample mass consumption, and chromatographic interferences from derivatization reagents and non-target compounds.
Methods: Here we demonstrate a highly efficient method to analyze the composition and compound specific isotopic ratios of C to C amines as well as ammonia based on solid phase micro-extraction (SPME) on-fiber derivatization.
Reduced contribution of sulfur to the mass extinction associated with the Chicxulub impact event.
Nat Commun
January 2025
Atomic and Mass Spectrometry-A&MS research unit, Department of Chemistry, Ghent University, Ghent, Belgium.
The Chicxulub asteroid impact event at the Cretaceous-Paleogene (K-Pg) boundary ~66 Myr ago is widely considered responsible for the mass extinction event leading to the demise of the non-avian dinosaurs. Short-term cooling due to massive release of climate-active agents is hypothesized to have been crucial, with S-bearing gases originating from the target rock vaporization considered an important driving force. Yet, the magnitude of the S release remains poorly constrained.
View Article and Find Full Text PDFTransformation processes of total suspended solids and dissolved organic matter in rivers: Influences of different land use sources and degradation processes.
Sci Total Environ
January 2025
China National Environmental Monitoring Centre, Beijing 100012, China.
The riverine dissolved organic matter (DOM) pool constitutes the largest and most dynamic organic carbon reservoir within inland aquatic systems. Human activities significantly alter the distribution of organic matter (OM) in rivers, thereby affecting the availability of DOM. However, the impact of total suspended solids (TSS) on DOM under anthropogenic influence remains insufficiently elucidated.
View Article and Find Full Text PDFHigh-precision Cu isotopic analysis of human dietary Cu sources via multi-collector ICP-mass spectrometry.
Food Chem
December 2024
Atomic and Mass Spectrometry - A&MS Research Unit, Department of Chemistry, Ghent University, 9000 Ghent, Belgium. Electronic address:
The disruption of Cu homeostasis is associated with the pathogenesis of many diseases and can result in alterations in Cu isotope fractionation. Changes in the Cu isotope ratio (Cu/Cu) of body fluids and tissues have been observed in liver disorders, cancers, and other diseases, displaying diagnostic/prognostic potential. However, it is not entirely clear whether certain physiological or lifestyle factors may also influence the bodily Cu isotopic composition, potentially obfuscating the signature of the pathology.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!