scholarly journals Storage Changes Stable Isotope Composition of Cucumbers

2021 ◽  
Vol 5 ◽  
Author(s):  
Micha Horacek ◽  
Wolfgang Papesch
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
Stable Isotope Composition ◽  
Vegetable Food ◽  
O Isotope ◽  
Linear Correlations ◽  
Special Relevance ◽  
Reference Samples

Vegetable food stuff produced under controlled and identical conditions from one farm of identical “age” (batch) has a similar isotopic composition. This fact can be used to control the origin of vegetables. This question is of special relevance when food-contaminations have to be traced back to the producer, or certain production claims have to be controlled. However, as vegetables are harvested, brought to whole-sale merchants and to retail shops, where they remain until being bought by the consumer, one has to consider possible changes in isotopic composition during this transfer period, when comparing vegetables of questioned origin with reference samples taken directly from the field/producer. We investigated changes in the isotope composition of vegetables during storage by studying as an example cucumbers from one batch. We stored the cucumbers in a vegetable storage under controlled conditions and removed one sample every day and analyzed its isotopic composition. We found changes in the δ15N and δ18O isotope values over the investigated period of 21 days, with both parameters showing positive linear correlations, and maximum enrichments with time of more than 1.5‰ for δ15N and more than 2‰ for δ18O. However, within the interval the samples remained in a saleable condition the isotope variations remained more or less within the variability of the sample batch. Our study demonstrates that changes in the isotopic signature in vegetables might occur after harvest during storage and have to be taken into account when (commercial) samples collected in a market are investigated.

Stable isotope composition of fluid inclusions in quartz minerals : New method for paleoaltimetry

2021 ◽  
Author(s):  
Raphaël Melis ◽  
Véronique Gardien ◽  
Gweltaz Mahéo ◽  
Christophe Lécuyer ◽  
Philippe-Hervé Leloup ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
Shear Zones ◽  
Isotopic Signature ◽  
Stable Isotope Ratio ◽  
New Method ◽  
Good Precision ◽  
Stable Isotope Composition ◽  
Geological Time ◽  
Quartz Veins

<p>Paleoaltimetry is a powerful tool to study tectonic, climate and surface processes interactions. Indeed, stable isotope composition of meteoric water can be correlated with the elevation of reliefs. The δ18O and δD of orogenic rainfall decrease while the elevation increase. Current paleoaltimetric methods based on stable isotope, including the study of pedogenic carbonates and micas associated with fault or shear zones, represent an indirect way to obtain stable isotope « paleometeoric fluid » composition. These methods do not provide simultaneously the δ18O and δD values implying the use of isotope exchange equation, source of signficant errors (up to +/- 1000m).</p><p>We have developed a new method which allow to directly acces at both the δ18O and δD of « paleometeoric » fluids with a good precision and margin of error less than +/- 200m . This method has been developed on the stable isotope composition of fluid inclusion trapped in quartz veins. The developed experimental protocol allows to extract small quantity of fluid (~10mL) and directly analyse both the δ18O and δD with a OA-ICOS Spectroscopy. Tested on 18 Miocene alpine quartz veins from the Mont-Blanc and the Chenaillet massifs the stable isotope composition of the fluids fit very well with meteoric isotopic signature and highlight the robustness of stable isotope ratio through geological time.</p><p>More over, our results indicate that Miocene precipitation was way more positive (-4,8 to -9 ‰ for δ18O and -38,2 to 68,8‰ for δD) in the Mont-Blanc massif area than modern precipitation (-12,9 to -18 ‰ for δ18O and -101,1 to -144,25‰ for δD) which indicate that the massif was still at low elevation at this time. In contrast the « paleoprecipitation » of the Chenaillet massif fall in the same range than modern precipitation (-83 to -120,3 ‰ for δD and -11,8 to -16,9 ‰ for δ18O) which indicate this massif has already reached his present altitude (~ 2500m).</p>

scholarly journals Isotopic composition of precipitation in Poland: a 44-year record

2019 ◽  
Vol 67 (6) ◽  
pp. 1637-1648 ◽  
Author(s):  
Marek Duliński ◽  
Kazimierz Różański ◽  
Anna Pierchała ◽  
Zbigniew Gorczyca ◽  
Michał Marzec
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
Isotope Composition ◽  
Environmental Isotopes ◽  
Monthly Precipitation ◽  
Stable Isotope Composition ◽  
Tritium Content ◽  
European Continent ◽  
The North ◽  
The North Atlantic Oscillation

Abstract Isotopic composition of precipitation (2H/1H and 18O/16O isotope ratios, tritium content) is nowadays widely used in numerous applications of environmental isotopes—most notably in hydrology, climatology and biogeochemistry. Here we present a long record (44 years) of stable isotope composition and tritium content in monthly precipitation available for the Krakow station (southern Poland). Krakow is the only site in Poland for which long-term record of the isotopic composition of monthly precipitation is available. The tritium data are discussed here in the context of generally declining levels of bomb tritium in the global atmosphere and growing influence of technogenic emissions of this isotope. Two aspects of temporal variability of stable isotope composition of precipitation collected in Krakow are discussed here: (i) seasonality and (ii) interannual changes of δ18O and δ2H signal. Whereas the seasonality of stable isotope signal is generated mainly by seasonally varying the degree of rainout of air masses bringing moisture from the source regions (subtropical Atlantic Ocean) to the centre of the European continent, the North Atlantic Oscillation seems to govern interannual changes of δ18O and δ2H on the decadal timescale. Progressing warming of the local atmosphere, in the order of 1.8 °C in the past four decades, leaves its imprint in stable isotope signal measured in Krakow precipitation; the slope of isotope–temperature relationship is in the order of 0.50‰/°C for δ18O and 3.5‰/°C for δ2H.

scholarly journals An Overview of Aquifer Physiognomies and the δ18O and δ2H Distribution in the South African Groundwaters

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 68
Author(s):  
Tamiru A. Abiye ◽  
Molla B. Demlie ◽  
Haile Mengistu
Keyword(s):  
Stable Isotope ◽  
Isotopic Composition ◽  
South African ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Isotopic Signature ◽  
Shallow Aquifer ◽  
Arid Zones ◽  
Mixing Effect ◽  
Groundwater Systems

A comprehensive assessment of the stable isotope distribution in the groundwater systems of South Africa was conducted in relation to the diversity in the aquifer lithology and corresponding hydraulic characteristics. The stable isotopes of oxygen (18O) and hydrogen (2H) in groundwater show distinct spatial variation owing to the recharge source and possibly mixing effect in the aquifers with the existing water, where aquifers are characterized by diverse hydraulic conductivity and transmissivity values. When the shallow aquifer that receives direct recharge from rainfall shows a similar isotopic signature, it implies less mixing effect, while in the case of deep groundwater interaction between recharging water and the resident water intensifies, which could change the isotope signature. As aquifer depth increases the effect of mixing tends to be minimal. In most cases, the isotopic composition of recharging water shows depletion in the interior areas and western arid zones which is attributed to the depleted isotopic composition of the moisture source. The variations in the stable isotope composition of groundwater in the region are primarily controlled by the isotope composition of the rainfall, which shows variable isotope composition as it was observed from the local meteoric water lines, in addition to the evaporation, recharge and mixing effects.

scholarly journals Chemical and stable isotope composition of surface and groundwater in the surroundings of the Los Humeros Caldera, Puebla, Mexico

2019 ◽  
Vol 98 ◽  
pp. 07013
Author(s):  
Thomas Kretzschmar ◽  
Matteo Lelli ◽  
Ruth Alfaro ◽  
Juan Ignacio Sanchez ◽  
Yann Rene Ramos
Keyword(s):  
Stable Isotope ◽  
Isotope Composition ◽  
Regression Line ◽  
Sustainable Use ◽  
Geothermal Reservoir ◽  
Maximum Temperature ◽  
Stable Isotope Composition ◽  
Local Fracture ◽  
Hydrogeological Model ◽  
Fracture Systems

It is important to develop a regional hydrogeological model to identify possible recharge and discharge areas for a sustainable use of a geothermal reservoir. The Los Humeros geothermal area is situated within five surficial watersheds and coveres an area of more than 15.000 km2. A total of 208 well and spring samples were collected between June 2017 and November 2018. The stable isotope data for this region define a regression line of δDH2O = 8.032·δ18O + 12 and indicate that groundwater is recharged by regional precipitation. At least 39 groundwater wells, with a maximum temperature of 35 °C, show temperatures above the reported mean average surface temperature of 15 °C. Characteristic elements for geothermal reservoir fluids (B, Li, As) are also present in these groundwaters, indicating a possible connection between the reservoir fluid and the local groundwater through local fracture systems. Concentration of B in these hot wells is between 150 and 35000 ppb.

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