Filtering by Subject: Chemistry

Climatic and geological insights on geochemical signatures left in ancient glass

Bongsu Chang, Bum Ki Lee, Jieun Seo, et al.

Published: 2024-02-25
Subjects: Chemistry, Earth Sciences, Geography

Glass artifacts have been the subject of extensive trade as exquisite items of the social elite since ancient times. Vestiges of their production and migration are still visible around the globe. To comprehend the historical narrative of human life encapsulated within them, it is imperative to ascertain their inception, which directly correlates with the identification of raw materials used in [...]

Non-target screening analysis reveals changes in the molecular composition of the Belukha Ice Core between the pre-industrial and industrial periods (1830-1980 CE)

Francois Burgay, Daniil Salionov, Thomas Singer, et al.

Published: 2024-01-28
Subjects: Chemistry, Environmental Sciences, Physical Sciences and Mathematics

Ice cores are environmental archives that are used to reconstruct past changes in the atmospheric aerosol composition. Most ice-core studies have focused mainly on inorganic species and a few dozen organic molecules. However, organic compounds can account for up to 90% of the aerosol composition, meaning that only a fraction of the organic constituents has been studied, limiting our understanding [...]

Improving Weather Prediction Technologies: Establishing a Relationship between Air Pollution and Weather Phenomena

Raghav Sriram

Published: 2023-08-11
Subjects: Chemistry, Oceanography and Atmospheric Sciences and Meteorology

The primary focus of this research is to establish a link between air quality, weather patterns, and climate dynamics. Employing a correlative methodology, the study aims to investigate the association between air pollution levels and the occurrence frequency of acid rain events. To accomplish this, extensive quantitative meteorological data gathered from weather stations situated in the [...]

Eocene (50-55 Ma) greenhouse climate recorded in nonmarine rocks of San Diego, CA, USA

Adrian Broz, Devin Pritchard-Peterson, Sarah Schneider, et al.

Published: 2023-08-08
Subjects: Chemistry, Climate, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Soil Science, Stratigraphy

Nonmarine rocks in sea cliffs of southern California store a detailed record of weathering under tropical conditions millions of years ago, where today the climate is much drier and cooler. This work examines early Eocene (~50-55 million-year-old) deeply weathered paleosols (ancient, buried soils) exposed in marine terraces of northern San Diego County, California, and uses their geochemistry and [...]

Volcanic Lightning and Prebiotic Chemistry on the Early Earth

Jeffrey L Bada

Published: 2022-09-16
Subjects: Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Based on the paper by Pan et al., on the early Earth >4.2 Ga with limited exposed land areas, coupled with an ice covered ocean, lightning could have been rare. This presents a conundrum because lightning is considered to be an important energy source needed for the synthesis of prebiotic compounds required for the origin of life. Lightning occurrence during eruptions on wide spread volcanic [...]

Isotopically labeled ozone: a new approach to elucidate the formation of ozonation products

Millaray Sierra Olea, Simon Kölle, Emil Bein, et al.

Published: 2022-09-06
Subjects: Chemical Engineering, Chemistry, Engineering, Environmental Sciences

As ozonation becomes a widespread treatment for removal of chemicals of emerging concern in wastewater treatment plant effluents, there are increasing concerns regarding the formation of ozonation products (OPs), and their possible impacts on the aquatic environment and eventually human health. In this study, a novel method was developed that utilizes heavy oxygen (18O2) for the production of [...]

Sorption vs Adsorption: the words they are a-changin', not the phenomena

Olivier Pourret, Jean-Claude Bollinger, Andrew Hursthouse, et al.

Published: 2022-05-17
Subjects: Chemistry, Earth Sciences, Environmental Sciences

In this discussion, we highlight that the terms sorption and adsorption are often confused and misused in many articles. Even if one thought their formal definition is well known, this does not appear to be the case. We recommend encouragement to adopt the word adsorption only when fully supported by appropriate data and using the sorption terminology when it is more speculative, typically in [...]

Multi-proxy assessment of surface sediments using APPI-P FTICR-MS reveals a complex biogeochemical record along a salinity gradient in the Pearl River estuary and coastal South China Sea

Jagos Radovic, Wei Xie, Renzo Silva, et al.

Published: 2021-12-10
Subjects: Analytical Chemistry, Biogeochemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Geochemistry, Physical Sciences and Mathematics

The Pearl River drains the second largest watershed in China, funnelling large amounts of freshwater and organic matter into the northern part of the South China Sea through an estuary characterized by pronounced biogeochemical gradients. In this study we analyzed organic extracts of surface sediments collected along land-sea transect that captures a transition from freshwater environment at the [...]

Crisis at the Salton Sea: The Vital Role of Science

Marilyn Fogel, Hoori Ajami, Emma Aronson, et al.

Published: 2021-03-03
Subjects: Atmospheric Sciences, Biogeochemistry, Chemistry, Climate, Earth Sciences, Environmental Chemistry, Environmental Public Health, Environmental Sciences, Environmental Studies, Geochemistry, Geology, Geomorphology, Hydrology, Medicine and Health Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Public Health, Social and Behavioral Sciences

The Salton Sea—a hypersaline, terminal lake in southern California—is in crisis. A combination of mismanagement and competition among federal, state and local agencies has hindered efforts to address declining lake levels and unstable water chemistry. This delay has heightened the public health threat to regional communities as retreating shorelines expose dry lakebed— a source of potentially [...]

Lithostratigraphy and chemostratigraphy of salt diapir sedimentary inclusions: unravelling Ediacaran salt–sediment interaction in the Flinders Ranges

Rachelle Kernen, Asmara Lehrmann, Piper Poe

Published: 2021-02-24
Subjects: Chemistry, Earth Sciences, Physical Sciences and Mathematics

Patawarta Diapir, located in the Central Flinders Ranges, South Australia, has been interpreted as a single allochthonous salt sheet containing Tonian-aged igneous and layered evaporite sedimentary intrasalt inclusions derived from the Callanna Group. Using detailed field mapping, petrographic analysis, and lithostratigraphic correlation within Patawarta Diapir, five primarily silty limestone [...]

Carbonate clumped isotope analysis (Δ47) of 21 carbonate standards determined via gas source isotope ratio mass spectrometry on four instrumental configurations using carbonate-based standardization and multi-year datasets

Deepshikha Upadhyay, Jamie Kaaren Lucarelli, Alexandrea Arnold, et al.

Published: 2020-11-28
Subjects: Chemistry, Earth Sciences, Physical Sciences and Mathematics

Rationale: Clumped isotope geochemistry examines the pairing or clumping of rare, heavy isotopes in molecules and provides information about the thermodynamic and kinetic controls on their formation. Since clumped isotope measurements of carbonate minerals were first published 15 years ago, interlaboratory offsets in calibrations have been observed, and laboratory and community practices for [...]

Sedimentary structures discriminations with hyperspectral imaging on sediment cores

Kévin Jacq, Rapuc William, Benoit Alexandre, et al.

Published: 2020-07-17
Subjects: Analytical Chemistry, Chemistry, Earth Sciences, Environmental Chemistry, Environmental Monitoring, Environmental Sciences, Multivariate Analysis, Optics, Physical Sciences and Mathematics, Physics, Sedimentology, Statistical Models, Statistics and Probability

Hyperspectral imaging (HSI) is a non-destructive high-resolution sensor, which is currently under significant development to analyze geological areas with remote devices or natural samples in a laboratory. In both cases, the hyperspectral image provides several sedimentary structures that need to be separated to temporally and spatially describe the sample. Sediment sequences are composed of [...]

Forecasting the localized bilateral effects of ocean acidification on the counter carbonate pump using recurrent neural networks

Eshan Ramesh

Published: 2020-07-08
Subjects: Artificial Intelligence and Robotics, Chemistry, Computer Sciences, Environmental Chemistry, Numerical Analysis and Scientific Computing, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

The counter carbonate pump(CCP) is responsible for carbon dioxide sequestration and cycling forms of carbon in the ocean. It is primarily driven by calcifying plankton, such as foraminifera, coccolithophores, and pteropods. These organisms are particularly vulnerable to ocean acidification, which can have disastrous effects on their skeletons and productivity, upsetting the marine carbon cycle in [...]

Toward stable, general machine-learned models of the atmospheric chemical system

Makoto Michael Kelp, Daniel J. Jacob, J. Nathan Kutz, et al.

Published: 2020-03-23
Subjects: Artificial Intelligence and Robotics, Chemistry, Computer Sciences, Earth Sciences, Environmental Chemistry, Environmental Sciences, Physical Sciences and Mathematics

Atmospheric chemistry models—used as components in models that simulate air pollution and climate change—are computationally expensive. Previous studies have shown that machine-learned atmospheric chemical solvers can be orders of magnitude faster than traditional integration methods but tend to suffer from numerical instability. Here, we present a modeling framework that reduces error [...]

Fate of organic compounds during transformation of ferrihydrite in iron formations

Stanislav Jelavic, Andrew Mitchell, Karina Krarup Sand

Published: 2020-01-30
Subjects: Biogeochemistry, Chemistry, Earth Sciences, Physical Chemistry, Physical Sciences and Mathematics

The absence of organic compounds from Precambrian iron formations (IF) challenges the hypothesis of the biogenic origin of IF. Here we address the fate of adsorbed organic compounds during transformation from ferrihydrite to hematite. We determined the binding energy between hematite and common molecular terminations found in extracellular polymeric substances and biofilms: carboxylic, hydroxyl [...]


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