New constraints of terrestrial and oceanic global gross primary productions from the triple oxygen isotopic composition of atmospheric CO and O.

Representations of the changing global carbon cycle under climatic and environmental perturbations require highly detailed accounting of all atmosphere and biosphere exchange. These fluxes remain unsatisfactory, as a consequence of only having data with limited spatiotemporal coverage and precision, which restrict accurate assessments. Through the nature of intimate coupling of global carbon and oxygen cycles via O and CO and their unique triple oxygen isotope compositions in the biosphere and atmosphere, greater insight is available.

Role of Vehicular Catalytic Converter Temperature in Emission of Pollutants: An Assessment Based on Isotopic Analysis of CO and NO.

Vehicular catalytic converters are used to regulate, reduce, and convert toxic and environmentally unfriendly compounds in exhaust gases into relatively inert and less harmful chemical species. The efficiency, however, is largely affected by the operating temperature of the converter which is set by the hot exhaust gas released from the combustion chamber. A major gas released during combustion is CO, and its multiply substituted isotopocule, namely, COO, provides a window of opportunity to probe directly the effective temperature of the converter in operation.

Variable thermoregulation of Late Cretaceous dinosaurs inferred by clumped isotope analysis of fossilized eggshell carbonates.

The thermal physiology of non-avian dinosaurs, especially the endothermic/ectothermic nature of their metabolism, inferred indirectly using body mass, biophysical modelling, bone histology and growth rate, has long been a matter of debate. Clumped isotope thermometry, based on the thermodynamically driven preference of C-O bond in carbonate minerals of fossilized eggshells, yields temperature of egg formation in the oviduct and can delineate the nature of thermoregulation of some extinct dinosaur taxa. In the present study, the clumped isotope thermometry was applied to the eggshells of a few species of modern birds and reptiles to show that it is possible to obtain the body temperatures of these species in most of the cases.

A new perspective of probing the level of pollution in the megacity Delhi affected by crop residue burning using the triple oxygen isotope technique in atmospheric CO.

Air quality in the megacity Delhi is affected not only by local emissions but also by pollutants from crop residue burning in the surrounding areas of the city, particularly the rice straw burning in the post monsoon season. As a major burning product, gaseous CO, which is rather inert in the polluted atmosphere, provides an alternative solution to characterize the impact of biomass burning from a new perspective that other common tracers such as particulate matters are limited because of their physical and chemical reactiveness. Here, we report conventional ([CO], δC, and δO) and unconventional (ΔO) isotope data for CO collected at Connaught Place (CP), a core area in the megacity Delhi, and two surrounding remote regions during a field campaign in October 18-20, 2017.

Measurement of O O and O O in atmospheric O using the 253 Ultra mass spectrometer and applications to stratospheric and tropospheric air samples.

Rationale: The doubly substituted isotopologues (e.g., O O, O O) in atmospheric O are potential tracers for ozone photochemistry and atmospheric temperatures.

Distribution of CO in Western Pacific, Studied Using Isotope Data Made in Taiwan, OCO-2 Satellite Retrievals, and CarbonTracker Products.

To assess sources and processes that affect the variability of CO at local to regional scales, we have analyzed the mixing ratio [CO] and stable isotopic compositions (δC and δO) of atmospheric CO for three years (2014-2016) in urban and sub-urban areas in Taipei, Taiwan. The data are compared with those from some background sites, viz., Lulin, Mauna Loa, and Minamitorishima, to evaluate how local emissions affect CO level regionally.

Oxygen isotope anomaly in tropospheric CO and implications for CO residence time in the atmosphere and gross primary productivity.

The abundance variations of near surface atmospheric CO isotopologues (primarily OCO, OCO, OCO, and OCO) represent an integrated signal from anthropogenic/biogeochemical processes, including fossil fuel burning, biospheric photosynthesis and respiration, hydrospheric isotope exchange with water, and stratospheric photochemistry. Oxygen isotopes, in particular, are affected by the carbon and water cycles. Being a useful tracer that directly probes governing processes in CO biogeochemical cycles, ΔO (=ln(1 + δO) - 0.

Identification of Anthropogenic CO Using Triple Oxygen and Clumped Isotopes.

Quantification of contributions from various sources of CO is important for understanding the atmospheric CO budget. Considering the number and diversity of sources and sinks, the widely used proxies such as concentration and conventional isotopic compositions (δC and δO) are not always sufficient to fully constrain the CO budget. Additional constraints may help in understanding the mechanisms of CO production and consumption.

Gravitational sampling electrospray ionization mass spectrometry for real-time reaction monitoring.

Rationale: The elucidation of chemical reaction mechanisms has attracted tremendous interest in recent years. Here, gravitational sampling electrospray ionization mass spectrometry (GS-ESI-MS) is used to explore a simple method for the real-time monitoring of chemical and biochemical reactions.

Methods: A sample solution in a stainless steel sample well is directly delivered through a fused-silica capillary due to the forces of gravity, capillary action, and electroosmotic flow (EOF).

Stable carbon isotopes in dissolved inorganic carbon: extraction and implications for quantifying the contributions from silicate and carbonate weathering in the Krishna River system during peak discharge.

We present a comparative study of two offline methods, a newly developed method and an existing one, for the measurement of the stable carbon isotopic composition (δ(13)C) of dissolved inorganic carbon (DIC; δ(13)CDIC) in natural waters. The measured δ(13)CDIC values of different water samples, prepared from laboratory Na2CO3, ground and oceanic waters, and a laboratory carbonate isotope standard, are found to be accurate and reproducible to within 0.5 ‰\ (1σ).