Biography

I study global chemical, physical and biological processes in the Earth's atmosphere and oceans, and their variations through time under natural and anthropogenic influences, by integrating fieldwork, laboratory studies and modelling into a coherent framework, often involving the use of stable isotopes.

This approach has been applied to nitrous oxide (N2O), nitrate, oxygen, nitrogen, argon and CO2. I have led studies on the isotopic composition of atmospheric N2O, emphasizing position-dependent 15N/14N isotope ratio measurements and the fate of N2O in stratospheric photolysis and photo-oxidation. I developed analytical methods to accurately measure N2O isotopes in troposphere, stratosphere, polar firn air and ice. This work allowed reconstruction of past changes and demonstrated increasing agricultural influences on atmospheric N2O. In laboratory experiments, I studied temperature- and wavelength-dependent isotope effects in N2O photolysis. I discovered that during photolysis the central nitrogen position always becomes more enriched in 15N than the terminal one, but that during photo-oxidation the opposite position-dependent fractionation occurs. This pattern allowed me to distinguish photolysis and photo-oxidation in the stratosphere.

I am also interested in rare isotope signatures, such as oxygen isotope anomalies (17O-excess, Δ(17O)) and multiply-substituted isotopologues (clumped isotopes) such as 15N15NO. The small 17O-excess of atmospheric N2O motivated me to consider how best to characterise such anomalies. My review of data reduction practices for CO2 isotope measurements revealed systematic uncertainties in global carbon budget calculations.

The N2O work led on to the first online gas chromatography-isotope ratio mass spectrometric method to measure Δ(17O) of nitrate, which drastically reduced sample sizes and enabled seawater analyses. Δ(17O) combined with nitrogen isotope ratios were used to understand the annual cycle of nitrate in coastal Antarctica, uncovering stratospheric influences and re-evaporation from surface snow. Low sample size requirements make this technique suitable for ice core studies of past changes in the atmospheric oxidation capacity.

I have also developed a sea-going membrane inlet mass spectrometer (MIMS). The instrument continuously measures dissolved oxygen, nitrogen, argon and CO2. Oxygen/argon ratios allow separation of physical and biological effects on gas concentrations and provide net community production estimates on unprecedentedly fine scales.

More recent work included studies of N2O and nitrate in marine and terrestrial environments as well as measurements of the chlorine (37Cl/35Cl) and carbon (13C/12C) of volatile organic compounds. As a member of the UEA Glider Group, I have been involved with deployments of oxygen sensors (optodes) on autonomous float (NAB 2008) and glider (GOPINA) platforms, in order to provide vital data on the oceanic carbon cycle and biological productivity estimates in a changing climate.

Career History

Academic Background

Kaiser Group website: https://kaiserlab.org

Nitrate isotope analysis: We offer nitrogen (15N/14N) and oxygen (18O/16O, 17O/16O) isotopic analyses of nitrate (NO3–) as analytical service, see here for more information.

PhD Studentships available

Other PhD Positions

Click here for other current PhD opportunities in the School of Environmental Sciences.  However, feel free to email me to discuss projects outside these areas and alternative sources of funding.

All Publications

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Walter, S., Kock, A., Steinhoff, T., Fiedler, B., Fietzek, P., Kaiser, J., Krol, M., Popa, M. E., Chen, Q., Tanhua, T., Röckmann, T.

(2016)

Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

in Biogeosciences

13.

pp. 323-340

Full Text UEA Repository

(Article)


Hull, T., Greenwood, N., Kaiser, J., Johnson, M.

(2016)

Uncertainty and sensitivity in optode-based shelf-sea net community production estimates

in Biogeosciences

13.

pp. 943-959

Full Text UEA Repository

(Article)


Lewicka-Szczebak, D., Dyckmans, J., Kaiser, J., Marca, A., Augustin, J., Well, R.

(2016)

Oxygen isotope fractionation during N2O production by soil denitrification

in Biogeosciences

13.

pp. 1129-1144

Full Text UEA Repository

(Article)


Damerell, G., Heywood, K., Thompson, A., Binetti, U., Kaiser, J.

(2016)

The vertical structure of upper ocean variability at the Porcupine Abyssal Plain during 2012-2013

in Journal of Geophysical Research - Oceans

121.

pp. 3075–3089

Full Text UEA Repository

(Article)


Prokopiou, M., Martinerie, P., Sapart, C. J., Witrant, E., Monteil, G. A., Ishijima, K., Bernard, S., Kaiser, J., Levin, I., Sowers, T., Blunier, T., Etheridge, D., Dlugokencky, E., Van de Wal, R. S. W., Röckmann, T.

(2016)

Constraining N2O emissions since 1940 using firn air isotope measurements in both hemispheres

Full Text

(Discussion paper)


Mino, Y., Sukigara, C., Honda, M. C., Kawakami, H., Matsumoto, K., Wakita, M., Kitamura, M., Fujiki, T., Sasaoka, K., Abe, O., Kaiser, J., Saino, T.

(2016)

Seasonal variations in the nitrogen isotopic composition of settling particles at station K2 in the western subarctic North Pacific

in Journal of Oceanography

72.

pp. 819–836

Full Text UEA Repository

(Article)


Hemming, M. P., Kaiser, J., Heywood, K. J., Bakker, D. C. E., Boutin, J., Shitashima, K., Lee, G., Legge, O., Onken, R.

(2016)

Measuring pH variability using an experimental sensor on an underwater glider

Full Text

(Discussion paper)


Onken, R., Fiekas, H., Beguery, L., Borrione, I., Funk, A., Hemming, M., Heywood, K. J., Kaiser, J., Knoll, M., Poulain, P., Queste, B., Russo, A., Shitashima, K., Siderius, M., Thorp-Küsel, E.

(2016)

High-Resolution Observations in the Western Mediterranean Sea: The REP14-MED Experiment

Full Text

(Discussion paper)


Vega, C. P., Pohjola, V. A., Samyn, D., Pettersson, R., Isaksson, E., Björkman, M. P., Martma, T., Marca, A., Kaiser, J.

(2015)

First ice core records of NO

in Journal of Geophysical Research: Atmospheres

120.

pp. 313-330

Full Text UEA Repository

(Article)


Biddle, L. C., Kaiser, J., Heywood, K. J., Thompson, A., Jenkins, A.

(2015)

Ocean glider observations of iceberg-enhanced biological production in the northwestern Weddell Sea: Iceberg enhanced production

in Geophysical Research Letters

42.

pp. 459-465

Full Text UEA Repository

(Article)


Mrozek, D. J., Van Der Veen, C., Kliphuis, M., Kaiser, J., Wiegel, A. A., Röckmann, T.

(2015)

Continuous-flow IRMS technique for determining the

in Atmospheric Measurement Techniques

8.

pp. 811-822

Full Text UEA Repository

(Article)


Barnes, M. K., Tilstone, G. H., Smyth, T. J., Widdicombe, C. E., Gloel, J., Robinson, C., Kaiser, J., Suggett, D. J.

(2015)

Drivers and effects of Karenia mikimotoi blooms in the western English Channel

in Progress in Oceanography

137.

pp. 456–469

Full Text UEA Repository

(Article)


Allin, S. J., Laube, J. C., Witrant, E., Kaiser, J., Mckenna, E., Dennis, P., Mulvaney, R., Capron, E., Martinerie, P., Röckmann, T., Blunier, T., Schwander, J., Fraser, P. J., Langenfelds, R. L., Sturges, W. T.

(2015)

Chlorine isotope composition in chlorofluorocarbons CFC-11, CFC-12 and CFC-113 in firn, stratospheric and tropospheric air

in Atmospheric Chemistry and Physics

15.

pp. 6867-6877

Full Text UEA Repository

(Article)


Vega, C. P., Björkman, M. P., Pohjola, V. A., Isaksson, E., Pettersson, R., Martma, T., Marca, A., Kaiser, J.

(2015)

Nitrate stable isotopes and major ions in snow and ice samples from four Svalbard sites

in Polar Research

34.

Full Text UEA Repository

(Article)


Ishijima, K., Takigawa, M., Sudo, K., Toyoda, S., Yoshida, N., Röckmann, T., Kaiser, J., Aoki, S., Morimoto, S., Sugawara, S., Nakazawa, T.

(2015)

Development of an atmospheric N

in Atmospheric Chemistry and Physics Discussions

15.

pp. 19947-20011

Full Text UEA Repository

(Article)


Gloël, J., Robinson, C., Tilstone, G. H., Tarran, G., Kaiser, J.

(2015)

Technical Note: Could benzalkonium chloride be a suitable alternative to mercuric chloride for preservation of seawater samples?

in Ocean Science Discussions

12.

pp. 1953-1969

Full Text UEA Repository

(Article)


Hull, T., Greenwood, N., Kaiser, J., Johnson, M.

(2015)

Uncertainty and sensitivity in optode-based shelf-sea net community production estimates

in Biogeosciences Discussions

12.

pp. 15611-15654

Full Text UEA Repository

(Article)


Walter, S., Kock, A., Steinhoff, T., Fiedler, B., Fietzek, P., Kaiser, J., Krol, M. C., Popa, M. E., Chen, Q., Tanhua, T., Röckmann, T.

(2015)

Isotopic evidence for biogenic molecular hydrogen production in the Atlantic Ocean

in Biogeosciences Discussions

12.

pp. 16431-16477

Full Text UEA Repository

(Article)


Lewicka-Szczebak, D., Dyckmans, J., Kaiser, J., Marca, A., Augustin, J., Well, R.

(2015)

The mechanism of oxygen isotope fractionation during N

in Biogeosciences Discussions

12.

pp. 17009-17049

Full Text UEA Repository

(Article)


Gloël, J., Robinson, C., Tilstone, G. H., Tarran, G., Kaiser, J.

(2015)

Technical note: Could benzalkonium chloride be a suitable alternative to mercuric chloride for preservation of seawater samples?

in Ocean Science

11.

pp. 947-952

Full Text UEA Repository

(Article)


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Professional Activities

  • Atmospheric chemistry: nitrous oxide, nitrate, nitrogen oxides, halocarbons, stable isotopes (13C, 15N, 17O, 18O, 37Cl), polar firn air and ice measurements
  • Marine biogeochemistry: net and gross biological productivity (oxygen, oxygen/argon, oxygen triple isotopologues), air-sea exchange of greenhouse gases (nitrous oxide, methane, carbon dioxide), benthic and pelagial nitrogen cycling
  • Terrestrial biogeochemistry: Arctic lakes (Greenland, Svalbard), freshwater, lagoons
  • Nitrate isotope analysis: We offer nitrogen (15N/14N) and oxygen (18O/16O, 17O/16O) isotopic analyses of nitrate (NO3) as analytical service, see here for more information.

Complete list of publications: UEA EPrints Digital Repository

Selected publications:

  • Kaiser, J. (2011) Technical note: Consistent calculation of aquatic gross production from oxygen triple isotope measurements. Biogeosciences, 8, 1793-1811, doi:10.5194/bg-8-1793-2011
  • Kaiser, J. (2008) Reformulated 17O correction of mass spectrometric stable isotope measurements in carbon dioxide and a critical appraisal of historic `absolute' carbon and oxygen isotope ratios Geochimica et Cosmochimica Acta, 72(5), 1312-1334, doi:10.1016/j.gca.2007.12.011
  • Kaiser, J., Hastings, M.G., Houlton, B.Z., Röckmann, T., Sigman, D.M. (2007). Triple oxygen isotope analysis of nitrate using the denitrifier method and thermal decomposition of N2O. Analytical Chemistry, 79(2), 599-607. doi:10.1021/ac061022s
  • Savarino, J. Kaiser, S. Morin, D.M. Sigman, and M.H. Thiemens (2006). Nitrogen and oxygen isotope constraints on the origin of atmospheric nitrate in coastal Antarctica. Atmospheric Chemistry and Physics, 7(8), 1925-1945, doi:10.5194/acp-7-1925-2007
  • Kaiser, J., A. Engel, R. Borchers, and T. Röckmann (2006). Probing stratospheric transport and chemistry with new balloon and aircraft observations of the meridional and vertical N2O isotope distribution. Atmospheric Chemistry and Physics, 6, 3535-3556, doi:10.5194/acp-6-3535-2006
  • Kaiser, J., M.K. Reuer, B. Barnett, B., and M.L. Bender (2005). Marine productivity estimates from continuous O2/Ar ratio measurements by membrane inlet mass spectrometry. Geophysical Research Letters, 32 (19), L19605, doi:10.1029/2005GL023459
  • Kaiser, J., T. Röckmann, and C.A.M. Brenninkmeijer (2004). Contribution of mass-dependent fractionation to the oxygen isotope anomaly of atmospheric nitrous oxide. Journal of Geophysical Research, 109 (D3), D03305, doi:10.1029/2003JD004088
  • Kaiser, J., C.A.M. Brenninkmeijer, and T. Röckmann (2002). Intramolecular 15N and 18O fractionation in the reaction of N2O with O(1D) and its implications for the stratospheric N2O isotope signature. Journal of Geophysical Research, 107 (D14), 4214, doi:10.1029/2001JD001506

Author profiles

Key Responsibilities

  • Extenuating Circumstances Panel, School of Environmental Sciences
  • UG Exam Board, School of Chemistry
  • Year Abroad Placement Director, School of Environmental Sciences
  • Advisor, School of Environmental Sciences
  • Advisor, School of Natural Sciences