Search results for "Isotopic signature"

Modeling Rain Isotopic Composition under Orographic Control: A Landscape Approach for Hydrogeological Applications

2021

Oxygen isotopic composition is useful for individuating recharge areas of groundwater bodies by the comparison with those of local rainfalls. While on a global scale general relationships, such as the isotopic vertical gradient or continentality effects, efficiently describe spatial variations of the isotopic signature, hydrogeological applications need spatial models that are more focused on the effects of local topographic structures and/or subsoil geology. This work presents a case study in northeastern Sicily (Italy) characterized by complex geological and orographic structures, in which isotopic composition of rainfalls is governed by orographic effects and the varying initial composit…

Evolution of the neodymium isotopic signature of neritic seawater on a northwestern Pacific margin: new constrains on possible end-members for the co…

2013

11 pages; International audience; The Neodymium(Nd) isotope composition of fish remains has beenwidely used to track past changes in oceanic circulation. Although the number of published Nd isotope data for the Cretaceous has markedly increased in the last years, no consensus has been reached on the structure of the oceanic circulation and its evolution during the Late Cretaceous. Yet this period is characterised bymajor geodynamical and climatic changes andmarked by the disappearance of global oceanic anoxic events inwhich changes in oceanic circulation modesmay have played a significant role. In this study we present the first record of Nd isotopic composition of fish remains from contine…

A combined dietary approach using isotope and dental buccal-microwear analysis of human remains from the Neolithic, Roman and Medieval periods from t…

2016

Stable isotope and dental-microwear analysis are methods commonly used to reconstruct dietary habits in modern and ancient human populations. However, it is rare that they are both used together in the same study, and here both methods are combined to obtain information on human dietary habits from the site of Tossal de les Basses (Alicante, Spain) through time. Middle Neolithic, Late Roman and Medieval (Islamic) individuals have been analyzed for carbon and nitrogen stable isotope ratios of bone collagen, as well as for buccal-dental microwear. Overall, δ13C and δ15N isotopic values show that for all periods the diet was mainly based on C3 terrestrial resources. However, the isotopic signa…

2008

Abstract. Sulfur isotope analysis of atmospheric aerosols is a well established tool for identifying sources of sulfur in the atmosphere, estimating emission factors, and tracing the spread of sulfur from anthropogenic sources through ecosystems. Conventional gas mass spectrometry averages the isotopic compositions of several different types of sulfur aerosol particles, and therefore masks the individual isotopic signatures. In contrast, the new single particle technique presented here determines the isotopic signature of the individual particles. Primary aerosol particles retain the original isotopic signature of their source. The isotopic composition of secondary sulfates depends on the i…

Sexes in gynodioeciousGeranium sylvaticumdo not differ in their isotopic signature or photosynthetic capacity

2017

• In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. • In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductivity, transpiration rate, water use efficiency and isotopic signatures were measured in plants growing in two habitats differing in light availability. • Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference…

Assigning Elephant Ivory with Stable Isotopes

2016

The international ivory trade remains one of the world’s most controversial wildlife trade issues. One of the main arguments for the trade prohibition is the fact that it is very difficult to distinguish legal from illegal ivory in the markets, so that the legal ivory trade would provide a perfect cover for smuggling. The purpose of this study was to analyze the variability of isotope ratios in ivory samples from Appendix I and II elephant populations in Africa to validate their potential for forensic purposes more quantitatively. We selected a subset of 293 data of ivory samples from the www.ivoryid.org database that stores isotopic ratios of δ13C, δ15N, δ18O, δ2H, and δ34S from more than …

Fluid geochemistry in a low-enthalpy geothermal field along a sector of southern Apennines chain (Italy)

2020

Abstract The chemical and isotopic features of the fluids (water and gases) in the Lucane thermal area (southern Italy) have been investigated in order to verify their origin, water temperature in the geothermal reservoir, and to recognize the main natural processes concerning the water composition during ascent towards the surface. The Lucane geothermal system is placed in the southern sector of the Apennines chains, a seismically active area, close to the southern base of the Mt. Alpi carbonate massif. Along the study area, two main sets of high-angle faults form an almost orthogonal fault system that, as suggested by local structural geology, acts as a preferential pathway for uprising d…

Geochemical insight into differences in the physical structures and dynamics of two adjacent maar lakes at Mt. Vulture volcano (southern Italy)

2013

[1] We report on the first geochemical investigation of the Monticchio maar lakes (Mt. Vulture volcano, southern Italy) covering an annual cycle that aimed at understanding the characteristic features of the physical structures and dynamics of the two lakes. We provide the first detailed description of the lakes based on high-resolution conductivity-temperature-depth (CTD) profiles, chemical and isotopic (H and O) compositions of the water, and the amounts of dissolved gases (e.g., He, Ar, CH4, and CO2). The combined data set reveals that the two lakes, which are separated by less than 200 m, exhibit different dynamics: one is a meromictic lake, where the waters are rich in biogenic and man…

Stable isotope fractionation in speleothems: Laboratory experiments

2010

Abstract In recent years, stalagmites have become important archives for paleoclimate. Several studies applying carbon and oxygen isotopes of stalagmites show a simultaneous increase of δ 13 C and δ 18 O along individual growth layers, which is interpreted as being indicative of isotope fractionation under disequilibrium conditions. In order to obtain robust paleoclimatic information from calcite precipitated under these non-equilibrium conditions it is important to improve the quantitative understanding of the corresponding isotope fractionation processes. Here we present laboratory experiments simulating calcite precipitation under cave-analogue conditions. The major focus was the investi…

Understanding the role of soil erosion on co2-c loss using (13)c isotopic signatures in abandoned Mediterranean agricultural land.

2016

Understanding soil water erosion processes is essential to evaluate the redistribution of soil organic carbon (SOC) within a landscape and is fundamental to assess the role of soil erosion in the global carbon (C) budget. The main aim of this study was to estimate the C redistribution and losses using (13)C natural abundance. Carbon losses in soil sediment, dissolved organic carbon (DOC) and CO2 emission were determined. Four bounded parallel plots were installed on a 10% slope. In the upper part of the plots, C3soil was replaced with C4soil. The SOC and δ(13)C were measured after 145.2mm rainfall in the upper (2m far from C4strip), middle (4m far from C4strip) lower (6m far from C4strip) t…