Granger, J., D.M. Sigman, M.M. Rohde, M.T. Maldonado, and P.D. Tortell. 2010. “N and O Isotope Effects During Nitrate Assimilation by Unicellular Prokaryotic and Eukaryotic Plankton Cultures”. Geochimica Et Cosmochimica Acta 74: 1030-40. doi:10.1016/j.gca.2009.10.044.

Knapp, A.N., D.M. Sigman, and F. Lipschultz. 2005. “N Isotopic Composition of Dissolved Organic Nitrogen and Nitrate at the Bermuda Atlantic Time-Series Study Site”. Global Biogeochemical Cycles 19: 1-15. doi:10.1029/2004GB002320.

Sigman, D.M., M.A. Altabet, R. Michener, D.C. McCorkle, B. Fry, and R.M. Holmes. 1997. “Natural Abundance-Level Measurement of the Nitrogen Isotopic Composition of Oceanic Nitrate: An Adaptation of the Ammonia Diffusion Method”. Marine Chemistry 57: 227-42. doi:10.1016/S0304-4203(97)00009-1.

Wang, X.T., A.L. Cohen, V.H. Luu, H.A. Ren, Z. Su, G.H. Haug, and D.M. Sigman. 2018. “Natural Forcing of the North Atlantic Nitrogen Cycle in the Anthropocene”. Proceedings of the National Academy of Sciences of the United States of America 115. National Academy of Sciences: 10606-11. doi:10.1073/pnas.1801049115.

Fripiat, F., D.M. Sigman, S.E. Fawcett, P.A. Rafter, M.A. Weigand, and J.-L. Tison. 2014. “New Insights into Sea Ice Nitrogen Biogeochemical Dynamics from the Nitrogen Isotopes”. Global Biogeochemical Cycles 28. American Geophysical Union: 115-30. doi:10.1002/2013GB004729.

Marconi, D., M.A. Weigand, P.A. Rafter, M.R. McIlvin, M. Forbes, K.L. Casciotti, and D.M. Sigman. 2014. “Nitrate Isotope Distributions on the US GEOTRACES North Atlantic Cross-Basin Section: Signals of Polar Nitrate Sources and Low Latitude Nitrogen Cycling”. Marine Chemistry 177. Elsevier B.V.: 143-56. doi:10.1016/j.marchem.2015.06.007.

Knapp, A.N., P.J. Difiore, C. Deutsch, D.M. Sigman, and F. Lipschultz. 2008. “Nitrate Isotopic Composition Between Bermuda and Puerto Rico: Implications for N2 Fixation in the Atlantic Ocean”. Global Biogeochemical Cycles 22. doi:10.1029/2007GB003107.

Marconi, D., M.A. Weigand, and D.M. Sigman. 2019. “Nitrate Isotopic Gradients in the North Atlantic Ocean and the Nitrogen Isotopic Composition of Sinking Organic Matter”. Deep-Sea Research Part I: Oceanographic Research Papers 145. Elsevier Ltd: 109-24. doi:10.1016/j.dsr.2019.01.010.

Zhang, E., S. Huang, Q. Ji, M. Silvernagel, Y. Wang, B.B. Ward, D.M. Sigman, and G. Wysocki. 2015. “Nitric Oxide Isotopic Analyzer Based on a Compact Dual-Modulation Faraday Rotation Spectrometer”. Sensors (Switzerland) 15. MDPI AG: 25992-8. doi:10.3390/s151025992.

Granger, J., D.M. Sigman, M.F. Lehmann, and P.D. Tortell. 2008. “Nitrogen and Oxygen Isotope Fractionation During Dissimilatory Nitrate Reduction by Denitrifying Bacteria”. Limnology and Oceanography 53. American Society of Limnology and Oceanography Inc.: 2533-45. doi:10.4319/lo.2008.53.6.2533.

Savarino, J., J. Kaiser, S. Morin, D.M. Sigman, and M.H. Thiemens. 2007. “Nitrogen and Oxygen Isotopic Constraints on the Origin of Atmospheric Nitrate in Coastal Antarctica”. Atmospheric Chemistry and Physics 7. European Geosciences Union: 1925-45. doi:10.5194/acp-7-1925-2007.

Ren, H.A., Y.-C. Chen, X.T. Wang, G.T.F. Wong, A.L. Cohen, T.M. DeCarlo, M.A. Weigand, H.-S. Mii, and D.M. Sigman. 2017. “Nitrogen Cycle: 21st-Century Rise in Anthropogenic Nitrogen Deposition on a Remote Coral Reef”. Science 356. American Association for the Advancement of Science: 749-52. doi:10.1126/science.aal3869.

Galbraith, E.D., D.M. Sigman, R.S. Robinson, and T.F. Pedersen. 2008. Nitrogen in Past Marine Environments. Nitrogen in the Marine Environment. Elsevier Inc. doi:10.1016/B978-0-12-372522-6.00034-7.

Altabet, M.A., C. Pilskaln, R. Thunell, C. Pride, D.M. Sigman, F. Chavez, and R. François. 1999. “The Nitrogen Isotope Biogeochemistry of Sinking Particles from the Margin of the Eastern North Pacific”. Deep-Sea Research Part I: Oceanographic Research Papers 46: 655-79. doi:10.1016/S0967-0637(98)00084-3.

Difiore, P.J., D.M. Sigman, T.W. Trull, M.J. Lourey, K. Karsh, G. Cane, and R. Ho. 2006. “Nitrogen Isotope Constraints on Subantarctic Biogeochemistry”. Journal of Geophysical Research: Oceans 111. Blackwell Publishing Ltd. doi:10.1029/2005JC003216.

Thunell, R.C., D.M. Sigman, F. Muller-Karger, Y. Astor, and R. Varela. 2004. “Nitrogen Isotope Dynamics of the Cariaco Basin, Venezuela”. Global Biogeochemical Cycles 18: 1-13. doi:10.1029/2003GB002185.

Kast, E.R., D.A. Stolper, A. Auderset, J.A. Higgins, H.A. Ren, X.T. Wang, A. Martínez-García, G.H. Haug, and D.M. Sigman. 2019. “Nitrogen Isotope Evidence for Expanded Ocean Suboxia in the Early Cenozoic”. Science 364. American Association for the Advancement of Science: 386-89. doi:10.1126/science.aau5784.

Zhang, X., D.M. Sigman, F.M.M. Morel, and A.M.L. Kraepiel. 2014. “Nitrogen Isotope Fractionation by Alternative Nitrogenases and past Ocean Anoxia”. Proceedings of the National Academy of Sciences of the United States of America 111. National Academy of Sciences: 4782-87. doi:10.1073/pnas.1402976111.

Luu, V.H., Y. Ryu, W. Darling, S. Oleynik, S. de Putron, A.L. Cohen, X.T. Wang, and D.M. Sigman. 2025. “Nitrogen Isotope Ratios across the Bermuda Coral Reef: Implications for Coral Nitrogen Sources and the Coral-Bound Nitrogen Isotope Proxy”. Frontiers in Marine Science Volume 12 - 2025. doi:10.3389/fmars.2025.1554418.

Sigman, D.M., and F. Fripiat. 2019. Nitrogen Isotopes in the Ocean. Encyclopedia of Ocean Sciences. Elsevier. doi:10.1016/B978-0-12-409548-9.11605-7.

Sigman, D.M., K.L. Karsh, and K.L. Casciotti. 2009. Nitrogen Isotopes in the Ocean. Encyclopedia of Ocean Sciences. Elsevier Ltd. doi:10.1016/B978-012374473-9.00632-9.

Leichliter, J.N., T. Lüdecke, A.D. Foreman, N.N. Duprey, D.E. Winkler, E.R. Kast, H.B. Vonhof, et al. 2021. “Nitrogen Isotopes in Tooth Enamel Record Diet and Trophic Level Enrichment: Results from a Controlled Feeding Experiment”. Chemical Geology 563. Elsevier B.V. doi:10.1016/j.chemgeo.2020.120047.

Lueders-Dumont, J.A., X.T. Wang, O.P. Jensen, D.M. Sigman, and B.B. Ward. 2018. “Nitrogen Isotopic Analysis of Carbonate-Bound Organic Matter in Modern and Fossil Fish Otoliths”. Geochimica Et Cosmochimica Acta 224. Elsevier Ltd: 200-222. doi:10.1016/j.gca.2018.01.001.

Straub, M., A. Auderset, L. de Leval, N. Piazzon, D. Maison, M.-C. Vozenin, J. Ollivier, B. Petit, D.M. Sigman, and A. Martínez-García. 2023. “Nitrogen Isotopic Composition As a Gauge of Tumor Cell Anabolism-to-Catabolism Ratio”. Scientific Reports 13. Nature Research. doi:10.1038/s41598-023-45597-z.

Erler, D.V., X.T. Wang, D.M. Sigman, S.R. Scheffers, A. Martínez-García, and G.H. Haug. 2016. “Nitrogen Isotopic Composition of Organic Matter from a 168 Year-Old Coral Skeleton: Implications for Coastal Nutrient Cycling in the Great Barrier Reef Lagoon”. Earth and Planetary Science Letters 434. Elsevier: 161-70. doi:10.1016/j.epsl.2015.11.023.

Ren, H.A., D.M. Sigman, R.C. Thunell, and M.G. Prokopenko. 2012. “Nitrogen Isotopic Composition of Planktonic Foraminifera from the Modern Ocean and Recent Sediments”. Limnology and Oceanography 57. American Society of Limnology and Oceanography Inc.: 1011-24. doi:10.4319/lo.2012.57.4.1011.

Smart, S.M., S.E. Fawcett, H.A. Ren, R. Schiebel, E.M. Tompkins, A. Martínez-García, L. Stirnimann, A. Roychoudhury, G.H. Haug, and D.M. Sigman. 2020. “The Nitrogen Isotopic Composition of Tissue and Shell-Bound Organic Matter of Planktic Foraminifera in Southern Ocean Surface Waters”. Geochemistry, Geophysics, Geosystems 21. Blackwell Publishing Ltd. doi:10.1029/2019GC008440.

Fripiat, F., A. Martínez-García, D. Marconi, S.E. Fawcett, S.H. Kopf, V.H. Luu, P.A. Rafter, R. Zhang, D.M. Sigman, and G.H. Haug. 2021. “Nitrogen Isotopic Constraints on Nutrient Transport to the Upper Ocean”. Nature Geoscience 14. Nature Research: 855-61. doi:10.1038/s41561-021-00836-8.

Robinson, R.S., and D.M. Sigman. 2008. “Nitrogen Isotopic Evidence for a Poleward Decrease in Surface Nitrate Within the Ice Age Antarctic”. Quaternary Science Reviews 27: 1076-90. doi:10.1016/j.quascirev.2008.02.005.

Horn, M.G., R.S. Robinson, T.A. Rynearson, and D.M. Sigman. 2011. “Nitrogen Isotopic Relationship Between Diatom-Bound and Bulk Organic Matter of Cultured Polar Diatoms”. Paleoceanography 26. Blackwell Publishing Ltd. doi:10.1029/2010PA002080.

Treibergs, L.A., S.E. Fawcett, M.W. Lomas, and D.M. Sigman. 2014. “Nitrogen Isotopic Response of Prokaryotic and Eukaryotic Phytoplankton to Nitrate Availability in Sargasso Sea Surface Waters”. Limnology and Oceanography 59. American Society of Limnology and Oceanography Inc.: 972-85. doi:10.4319/lo.2014.59.3.0972.

Rao, Z.C., J.A. Lueders-Dumont, G.L. Stringer, Y. Ryu, K. Zhao, S.C.B. Myneni, S. Oleynik, G.H. Haug, A. Martínez-García, and D.M. Sigman. 2024. “A Nitrogen Isotopic Shift in Fish Otolith-Bound Organic Matter During the Late Cretaceous”. Proceedings of the National Academy of Sciences of the United States of America 121. National Academy of Sciences. doi:10.1073/pnas.2322863121.

Pride, C., R. Thunell, D.M. Sigman, L.D. Keigwin, M.A. Altabet, and E. Tappa. 1999. “Nitrogen Isotopic Variations in the Gulf of California since the Last Deglaciation: Response to Global Climate Change”. Paleoceanography 14. Blackwell Publishing Ltd: 397-409. doi:10.1029/1999PA900004.

Prokopenko, M.G., M.B. Hirst, L. De Brabandere, D.J.P. Lawrence, W.M. Berelson, J. Granger, B.X. Chang, et al. 2013. “Nitrogen Losses in Anoxic Marine Sediments Driven by Thioploca-Anammox Bacterial Consortia”. Nature 500: 194-98. doi:10.1038/nature12365.

Han, E., S.H. Kopf, A. Maloney, X. Ai, D.M. Sigman, and X. Zhang. 2025. “Nitrogen Stable Isotope Fractionation by Biological Nitrogen Fixation Reveals Cellular Nitrogenase Is Diffusion Limited”. PNAS Nexus 4: pgaf061. doi:10.1093/pnasnexus/pgaf061.

Peng, X., S.E. Fawcett, N. Van Oostende, M.J. Wolf, D. Marconi, D.M. Sigman, and B.B. Ward. 2018. “Nitrogen Uptake and Nitrification in the Subarctic North Atlantic Ocean”. Limnology and Oceanography 63. Wiley Blackwell: 1462-87. doi:10.1002/lno.10784.

Costa, K.M., J.F. McManus, R.F. Anderson, H.A. Ren, D.M. Sigman, G. Winckler, M.Q. Fleisher, F. Marcantonio, and A.C. Ravelo. 2016. “No Iron Fertilization in the Equatorial Pacific Ocean During the Last Ice Age”. Nature 529. Nature Publishing Group: 519-22. doi:10.1038/nature16453.

Kwon, E.Y., M.P. Hain, D.M. Sigman, E.D. Galbraith, J.L. Sarmiento, and J.R. Toggweiler. 2012. “North Atlantic Ventilation of Southern-Sourced Deep Water in the Glacial Ocean”. Paleoceanography 27. Blackwell Publishing Ltd. doi:10.1029/2011PA002211.

Haug, G.H., A. Ganopolski, D.M. Sigman, A. Rosell-Mele, G.E.A. Swann, R. Tiedemann, S.L. Jaccard, et al. 2005. “North Pacific Seasonality and the Glaciation of North America 2.7 Million Years ago”. Nature 433: 821-25. doi:10.1038/nature03332.

Straub, M., M.M. Tremblay, D.M. Sigman, A.S. Studer, H.A. Ren, J.R. Toggweiler, and G.H. Haug. 2013. “Nutrient Conditions in the Subpolar North Atlantic During the Last Glacial Period Reconstructed from Foraminifera-Bound Nitrogen Isotopes”. Paleoceanography 28. Blackwell Publishing Ltd: 79-90. doi:10.1002/palo.20013.