Singly and doubly substituted isotopocules of nitrous oxide and their application

in environmental studies

Kristýna Kantnerová

Overview

2

introduction about N2O

QCLAS method

applications in our lab with singly substituted isotopologues

development for doubly substituted isotopologues

Introduction important trace gas

contribution by 6 % to global warming

depletion of stratospheric ozone

increasing atmospheric concentration, 328 ppb (2015)

3

anthropogenic sourcesnatural sources

4

NO2-NH3 NH2OH NO3

-

N2O

NO3- NO2

- NO N2O N2

ammonia-oxidizing bacteria (AOB)ammonia-oxidizing archaea (AOA) denitrifying bacteria

5

Aerobic environment

6

Anaerobic environment

Isotopic studies of N2O

αβ

isotopologue label abundance14N14N16O 446 9.903 x 10-1 the most abundant one14N15N16O 456 3.641 x 10-3

singly substituted15N14N16O 546 3.641 x 10-3

14N14N18O 448 1.986 x 10-3

14N14N17O 447 3.762 x 10-4

15N15N16O 556 1.339 x 10-5

multiply substituted

“clumped isotopes”

14N15N18O 458 7.300 x 10-6

15N14N18O 548 7.300 x 10-6

14N15N17O 457 1.383 x 10-6

15N14N17O 547 1.383 x 10-6

15N15N18O 558 2.684 x 10-8

15N15N17O 557 5.085 x 10-9

7

SP 446

446

1

15N site preference

Isotopic studies of N2O

8

Keeling plots

9

IRMS tradition

Molecular spectroscopy

10

laser

detector

HCl

figure adaptedfrom Jana Jágerská

mid-IR light

HCl

spectrum

Isotopes in molecular spectroscopy

11

H35ClH37Cl 35Cl : 37Cl = 3 : 1

line strengths from HITRAN2012, spectrum simulated using program from http://faculty.evansville.edu/bl22/simul.html

reduced mass

N2O ro-vibrational spectra

12 446 and singly substituted – HITRAN2012clumped – simulations in PGOPHER based on spectroscopic constants from Amiot 1976, Toth 1991, Wang et al. 2009 and Jun-he Du et al. 2011

99.03 %

0.364 %

0.364 %

0.198 %

0.37 ‰

13.2 permeg

7.2 permeg

7.2 permeg

Analytical technique (TREX-QCLAS)

13

Singly substituted isotopocules

14

laser

Field study #1 – southern Germany

15

Fendt

PhD project – Erkan Ibraim

Field study #1 – southern Germany

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June – August 2016 intensively managed grassland research site local N2O fluxes, meteo and wind observation

mobile lab2 m sampleinlet

PhD project – Erkan Ibraim

Field study #2 – central Switzerland

17

Beromünster

PhD project – Erkan Ibraim

Field study #2 – central Switzerland

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September – December 2017 in central Switzerland intensively managed grassland research site TREX-QCLAS using flux chambers

PhD project – Erkan Ibraim

Study #3 – high-altitude station Jungfraujoch

19

Jungfraujoch

Eliza Harris & Longfei Yu

Study #3 – high-altitude station Jungfraujoch

20

identification of seasonal variability since April 2014, ongoing stratosphere-troposhere exchange observable

Eliza Harris & Longfei Yu

Clumped isotopes in N2O

21

clumping thermodynamically favored

isotopologue label abundance14N14N16O 446 9.903 x 10-1

14N15N16O 456 3.641 x 10-3

15N14N16O 546 3.641 x 10-3

14N14N18O 448 1.986 x 10-3

14N14N17O 447 3.762 x 10-4

15N15N16O 556 1.339 x 10-5

14N15N18O 458 7.300 x 10-6

15N14N18O 548 7.300 x 10-6

reproduced using data and information from Wang et al. 2004, for population having ratio of isotopes equal to reference standards AIR-N2 and VSMOW

Clumped isotopes in N2O – IRMS

22

Thermo Scientific™ 253 Ultra™

nominal mass isotopologue label abundance

4614N14N18O 448 1.986 x 10-3

15N15N16O 556 1.339 x 10-5

4714N15N18O 458 7.3 x 10-6

15N14N18O 548 7.3 x 10-6

23

Clumped isotopes in N2O

99.03 %

0.364 %

0.364 %

0.198 %

0.37 ‰

13.2 permeg

7.2 permeg

7.2 permeg

446 and singly substituted – HITRAN2012clumped – simulations in PGOPHER based on spectroscopic constants from Amiot 1976, Toth 1991, Wang et al. 2009 and Jun-he Du et al. 2011

New reference scale for clumped N2O

24

equilibration of N2O – driving into stochastic (random) distribution

different temperatures – different equilibrium composition, calculated using statistical thermodynamics predictions

1 ∙ 1000 ‰) reference – stochastic (random) distribution

reproduced using data and information from Wang et al. 2004, for population having ratio of isotopes equal to reference standards AIR-N2 and VSMOW

Summary

25

TREX-QCLAS for singly substituted isotopologues

selective and precise analysis of clumped isotopes

a new reference isotopic scale has been developed

Outlook

applications for clumped N2O isotopic signatures from pure microbial cultures

NO2-NH3 NH2OH NO3

-

N2O

NO2- NO

N2O

N2

nitrification denitrification- bacterial- fungal

Acknowledgement

26

Joachim Mohn – supervisor at Empa Dübendorf

Stefano Bernasconi – supervisor at ETH Zürich

lab people – Kerstin Zeyer, Sarah Eggleston, Erkan Ibraim, Longfei Yu, Béla Tuzson, Lukas Emmenegger

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Thank you for the attention!

Used figures

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http://www.motherearthnews.com/-/media/Images/MEN/Editorial/Articles/Magazine-Articles/2016/04-01/The-Benefits-of-Earthworms-and-How-to-Attract-Them/soil-and-worm-jpg.jpg

https://images.designtrends.com/wp-content/uploads/2016/02/24090853/Ocean-Wave-Dolphins-Wallpaper.jpg

https://www.kullabs.com/uploads/industry.jpg

http://constantine.typepad.com/.a/6a0120a7fc3be9970b01a73d8a8038970d-pi

https://www.kwl.ca/sites/default/files/03_0.jpg

http://www2.ess.ucla.edu/~schauble/MoleculeHTML/N2O_html/N2O_nu3.gif

https://www.philpoteducation.com/pluginfile.php/1363/mod_book/chapter/1333/14.2.6b.jpg