Jabrane Labidi - methane clumped

Lina Taenzer, Ed young, Will Leavitt and others (including yours truly) just published a nice article in GCA! we show that the methane clumped isotopologue signatures of biological methane is the result of an effect coined "combinatorial effect" by others. Basically, we conventionally calculate deviations of clumped signatures with respect to a stochastic distribution. We show that is some instances, the stochastic distribution is a poor representation of the isotopic budget in a given molecule. When that happens, the stochastic abundance of doubly-substituted isotopologues is over-estimated. This causes anomously low signatures in natural samples. 
This doesn't prevent interpreting the negative anomalies in  CH4 clumped signatures as tracers of biogenic methane, but this yields new information on the genesis of such peculiar deficits. 
Hit me up for a pdf version of the article!  or find it here:

Nitrogen isotopologues - only at UCLA - Jabrane Labidi

The isotopologue 15N15N of di-nitrogen could be measured in natural samples only at UCLA, in Edward Young's laboratory, with the Panorama mass spectrometer (see picture below). Only a large-radius mass spectrometer such as the Panorama, unique in the world, may allow resolving 15N15N from other compounds. This work's success is entirely due to the beauty of this instrument!
Will upload a picture of the Panorama at UCLA!

Nitrogen isotopologues reveal the origin of nitrogen in our planetary interior - Jabrane Labidi

Hi All, 
We've published our work in the journal Nature. We show that we can eliminate the confounding effect of air contamination in volcanic and hydrothermal gases, for the specific case of nitrogen. By substracting air contamination, we derive the di-nitrogen (N2) molecular weight in various mantle sources. 
A new finding here is that various mantle sources, with variable 15N/14N ratios, have a near-constant N2/3He ratio. Because 3He is in the deep Earth is not recycled, the constant N2/3He ratios argue against nitrogen addition via subduction in various mantle sources. 
We built a 2-box model to show how over 4.5 Ga, the mantle and air may have exchanged considerably less nitrogen than previously suggested. In other words, the possibility that mantle nitrogen is primordial can no longer be excluced. In this theory, nitrogen would have been inherited from the time the Earth was being built via planetary accretion. 
proud of this work!

Here is a link to view the pdf of the arti…

Jabrane Labidi - News and Views by Rita Parai

The news and views article written by colleague and carnegie alumni Rita Parai is amazing. I will seriously use some of the vocabulary she uses in her document to explain the notion of clumped isotopes to a general audience

a pdf version of Rita's article is available for free on the nature website! go check it out

Jabrane Labidi - Nitrogen in the mantle

The text written up, after the CNRS press release, in english:

Earth’s atmosphere is made up of 78% nitrogen and 21% oxygen, a mixture that is unique in the Solar System1. The oxygen was produced by some of the first living organisms. But where did the nitrogen come from? Did it escape from Earth’s mantle through volcanic activity? To try to answer these questions, Jabrane Labidi, a CNRS researcher at the Institut de Physique du Globe de Paris (CNRS/IPGP/IGN)2 and his colleagues collected samples of gas from several volcanic sites on our planet. Their study, published on 16 March 2020 in the journal Nature, shows that nitrogen from magma formed within the mantle does not have the same isotopic3 composition as atmospheric nitrogen, implying that the latter does not come from degassing of the mantle. However, the team were able to use these measurements to identify, in geysers, fumaroles and other phenomena involving volcanic gase…

Jabrane Labidi - We published a thing in Nature

here is the CNRS press release. They definitely stretched it and went for the 'volcanic eruption prediction' thing. but still fun. Will post other articles about this
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