{"id":478033,"date":"2026-10-10T09:13:22","date_gmt":"2026-10-10T16:13:22","guid":{"rendered":"https:\/\/climatescience.press\/?p=478033"},"modified":"2026-10-10T09:13:24","modified_gmt":"2026-10-10T16:13:24","slug":"rare-atomic-pair-reveals-where-earths-nitrogen-really-goes","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=478033","title":{"rendered":"Rare Atomic Pair Reveals Where Earth\u2019s Nitrogen Really Goes"},"content":{"rendered":"\n<figure class=\"wp-block-image is-resized\"><img data-recalc-dims=\"1\" height=\"485\" width=\"723\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/0-Rare-Atomic-Pair-Reveals-Where-Earths-Nitrogen-Really-Goes.jpg?resize=723%2C485&#038;ssl=1\" alt=\"Illustration depicting the nitrogen cycle on Earth, highlighting the role of rare isotopic pair 15N, terrestrial pathways, aquatic pathways, and microbial processes in nitrogen conversion.\" style=\"aspect-ratio:1.4890829694323144;width:1023px;height:auto\"\/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Scientists have developed a new way to track microbial nitrogen removal using the rare pairing of two heavy nitrogen-15 atoms in N\u2082 gas molecules.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article (by Harrison Tasoff of UC Santa Barbara, in collaboration with Holly Ober of UCLA) covers research published in <em>Science<\/em> on October 8, 2026. Biogeochemists from UC Santa Barbara, UCLA, and other institutions showed that this rare isotopic <strong>\u201cclumping\u201d <\/strong>acts as a natural fingerprint for how much nitrogen microbes convert back into gas.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>The problem<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Nitrogen is essential for life (proteins, DNA), but excess nitrogen compounds in water, from fertilizer runoff, wastewater, etc., can degrade water quality, fuel harmful algal blooms, and create oxygen- depleted<strong> \u201cdead zones\u201d<\/strong>. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Microbes help by converting usable nitrogen compounds into N\u2082 gas<\/strong> that escapes to the atmosphere (via processes like denitrification). Measuring this removal has been difficult because large amounts of atmospheric N\u2082 dissolve in water and mask the microbial signal.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>The clue from two atoms<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">N\u2082 consists of two nitrogen atoms. Most are the common isotope <strong>nitrogen- 14<\/strong>; a small fraction is the heavier nitrogen-15. Extremely rarely, both atoms in a molecule are <strong>nitrogen- 15<\/strong> (\u00b9\u2075N\u00b9\u2075N).<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In atmospheric nitrogen, these two heavy atoms pair up more often than random chance would predict (an anomalous<strong> \u201cclumped isotope\u201d<\/strong> signature from high-atmosphere photochemistry).<\/li>\n\n\n\n<li>Microbially produced N\u2082 has the isotopes paired nearly at random (due to enzyme kinetics).<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">When microbial N\u2082 mixes with atmospheric N\u2082, it dilutes the excess of heavy- heavy pairs. Measuring the relative abundance of this rare molecule therefore reveals how much of the gas came from microbes.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>How they measured it<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The team used UCLA\u2019s large <strong>Panorama high- resolution mass spectrometer<\/strong>, which can separate molecules with tiny mass differences that ordinary instruments cannot resolve. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>They analyzed samples from diverse environments:<\/strong> Texas groundwater, lakes in Antarctica and Minnesota, Southern California coastal basins, the Bay of Bengal, and deep- sea sediments off Alaska. Microbial mats at methane seeps, for example, emerged as hotspots for nitrogen conversion.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Lead author Jiarui Liu (who did the work as a postdoc at UCLA and UCSB\u2019s Marine Science Institute) and co- authors including Edward Young (UCLA), David Valentine (UCSB), and Alan Seltzer (University College Dublin) emphasize that while the technique currently requires specialized equipment and is not yet for routine field use, it offers a <strong>powerful new geochemical tool<\/strong> for understanding <strong>Earth\u2019s nitrogen cycle<\/strong>.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"723\" height=\"723\" data-attachment-id=\"478041\" data-permalink=\"https:\/\/climatescience.press\/?attachment_id=478041\" data-orig-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?fit=1280%2C1280&amp;ssl=1\" data-orig-size=\"1280,1280\" data-comments-opened=\"1\" data-image-title=\"image\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?fit=723%2C723&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=723%2C723&#038;ssl=1\" alt=\"Underwater scene showcasing textured rocks covered with yellow and grayish biofilm or algae against a dark background.\" class=\"wp-image-478041\" srcset=\"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=640%2C640&amp;ssl=1 640w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=450%2C450&amp;ssl=1 450w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=60%2C60&amp;ssl=1 60w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=550%2C550&amp;ssl=1 550w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?resize=50%2C50&amp;ssl=1 50w, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/image-72.png?w=1280&amp;ssl=1 1280w\" sizes=\"auto, (max-width: 723px) 100vw, 723px\" \/><figcaption class=\"wp-element-caption\">Analysis revealed that the microbial mats at methane seeps, like this one off the coast of Southern California, can be hotspots for converting nitrogen compounds into nitrogen gas. Credit Woods Hole Oceanographic Institution\/ Submersible Alvin<\/figcaption><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Clumped isotope theory (or clumped- isotope geochemistry) studies the tendency of rare, heavy isotopes to bond preferentially with one another within molecules, rather than being randomly distributed among the more common light isotopes.<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Core idea<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Ordinary stable- isotope geochemistry measureOrdinary stable-isotope geochemistry measures bulk ratios such as<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N\/<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>14<\/mn><\/msup><\/mrow><\/semantics><\/math>N (\u03b4<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>13<\/mn><\/msup><\/mrow><\/semantics><\/math>C\/<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>12<\/mn><\/msup><\/mrow><\/semantics><\/math>C (\u03b4<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>13<\/mn><\/msup><\/mrow><\/semantics><\/math>C)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>18<\/mn><\/msup><\/mrow><\/semantics><\/math>O\/<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>16<\/mn><\/msup><\/mrow><\/semantics><\/math>O (\u03b4<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>18<\/mn><\/msup><\/mrow><\/semantics><\/math>O)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Clumped- isotope geochemistry goes one step further: it quantifies how often two (or more) rare isotopes occur <em>together<\/em> in the same molecule, the \u201cclumps.\u201d<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Examples of clumped isotopExamples of clumped isotopologues:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>In nitrogen gas (N\u2082):<\/strong> <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N (mass- 30)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>In CO\u2082 or carbonate<\/strong>: <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>13<\/mn><\/msup><\/mrow><\/semantics><\/math>C<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>18<\/mn><\/msup><\/mrow><\/semantics><\/math>O<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>16<\/mn><\/msup><\/mrow><\/semantics><\/math>O (mass- 47)<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>In methane:<\/strong> <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>13<\/mn><\/msup><\/mrow><\/semantics><\/math>CH\u2083D or <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>12<\/mn><\/msup><\/mrow><\/semantics><\/math>CH\u2082D\u2082<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Stochastic (random) baseline<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">If isotopes combined purely by chance, the abundance of a doubly substituted molecule would simply be the product of the individual isotope abundances.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For N\u2082, the expected stochastic fraction of <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N is roughly <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mo stretchy=\"false\">(<\/mo><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N abundance<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mo stretchy=\"false\">)<\/mo><mn>2<\/mn><\/msup><\/mrow><\/semantics><\/math>.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Why clumping occurs<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Bonds between two heavy isotopes have slightly lower zero-point vibrational energy than bonds between light isotopes or mixed pairs. Thermodynamics therefore favor <strong>\u201cclumping\u201d of heavy isotopes<\/strong> because it lowers the molecule\u2019s total energy.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This preference is<strong> temperature- dependent:<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>At low temperatures, the energy difference matters more \u2192 more clumping (higher enrichment relative to stochastic).<\/li>\n\n\n\n<li>At high temperatures, thermal energy overwhelms the small energy difference \u2192 the distribution approaches pure randomness.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">The deviation from randomness is reported as a \u0394 value (in per mil, \u2030):<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" display=\"block\"><semantics><mrow><msub><mi mathvariant=\"normal\">\u0394<\/mi><mi>i<\/mi><\/msub><mo>=<\/mo><mrow><mo fence=\"true\">(<\/mo><mfrac><msub><mi>R<\/mi><mtext>sample<\/mtext><\/msub><msub><mi>R<\/mi><mtext>stochastic<\/mtext><\/msub><\/mfrac><mo>\u2212<\/mo><mn>1<\/mn><mo fence=\"true\">)<\/mo><\/mrow><mo>\u00d7<\/mo><mn>1000<\/mn><\/mrow><\/semantics><\/math>\u0394<em>i<\/em>\u200b=(<em>R<\/em>stochastic\u200b<em>R<\/em>sample\u200b\u200b\u22121)\u00d71000<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">where <em>R<\/em> is the ratio of the clumped isotopologue to a reference isotopologue.<br>\u0394 = 0 \u2030 means a purely stochastic distribution. Positive \u0394 means excess clumping.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Key applications<\/strong><\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Paleothermometry (most famous use)<\/strong><br>In carbonate minerals, the amount of <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>13<\/mn><\/msup><\/mrow><\/semantics><\/math>1C\u2013<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>18<\/mn><\/msup><\/mrow><\/semantics><\/math>O clumping (\u0394\u2084\u2087) records the temperature at which the mineral formed, <em>independent<\/em> of the isotopic composition of the water. This has revolutionized paleoclimate reconstruction.<\/li>\n\n\n\n<li><strong>Tracing processes (as in the nitrogen paper)<\/strong><br>Atmospheric N\u2082 has a large excess of <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N (\u0394\u2083\u2080 \u2248 +19 \u2030) produced by photochemical and ion-molecule reactions high in the atmosphere.<br>Microbial processes (denitrification, anammox) produce N\u2082 with near- stochastic pairing (\u0394\u2083\u2080 \u2248 0 \u2030).<br>Mixing of the two sources dilutes the atmospheric excess, allowing scientists to quantify how much N\u2082 came from microbes.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">Other controls on clumping include kinetic isotope effects, mixing of reservoirs with different bulk compositions, diffusion, and certain photochemical or biological fractionations.<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Measurement<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Because the clumped species are extremely rare (parts per million or less), high -resolution isotope- ratio mass spectrometers (or specialized laser techniques) are required to resolve them from interferences of nearly identical mass.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In short, clumped- isotope theory turns the internal arrangement of isotopes within molecules into a powerful tracer of temperature, reaction pathways, and mixing, information that bulk isotope ratios alone cannot provide.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">_____________________________________________________________________________________<\/p>\n\n\n\n<p class=\"has-large-font-size wp-block-paragraph\"><strong>Natural <sup>15<\/sup>N<sup>15<\/sup>N abundances constrain fixed nitrogen loss<\/strong><\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Editor\u2019s summary<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Nitrogen gas (N\u2082) is produced naturally by either photochemical reactions in the atmosphere or microbial processes in the biosphere, but the magnitudes of those sources are poorly quantified. Liu <em>et al.<\/em> showed that the abundance of the rare <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>15N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>15N isotopologue can be used to determine the amount of biogenic N\u2082 production in aquatic environments, thereby allowing physical and biological N\u2082 sources to be distinguished. This approach, applied to a wide spectrum of surface and ground water bodies, will help to better constrain the global nitrogen cycle.<br>\u2014Jesse Smith<\/p>\n\n\n\n<h3 class=\"wp-block-heading has-medium-font-size\"><strong>Abstract<\/strong><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Nitrogen regulates primary productivity across much of the biosphere, yet fixed nitrogen loss remains poorly constrained because existing methods rely on indirect proxies or ex situ experiments.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In this study, the authors show that <strong>natural abundances of the rare <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N isotopologue of dinitrogen (N\u2082)<\/strong> provide a direct tracer of biological N\u2082 production across diverse aquatic environments.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>N\u2082 produced by denitrification and anammox has a <strong>near- stochastic<\/strong> <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N distribution (\u2248 0 \u2030).<\/li>\n\n\n\n<li>Atmospheric N\u2082 carries a distinct <strong><math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N excess of ~19 \u2030<\/strong>.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">This large contrast allows the two sources to be quantitatively distinguished.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Across aquifers, stratified lakes, coastal basins, oxygen minimum zones, and marine sediments, <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N measurements reveal widespread nitrogen loss that was previously obscured by physical gas accumulation and nitrogen fixation.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Natural <math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N<math xmlns=\"http:\/\/www.w3.org\/1998\/Math\/MathML\"><semantics><mrow><msup><mrow><\/mrow><mn>15<\/mn><\/msup><\/mrow><\/semantics><\/math>N abundances therefore provide a general framework for directly constraining fixed nitrogen loss across the <strong>aquatic nitrogen cycle<\/strong>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This is the peer- reviewed paper underlying the popular- science articles. <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>The full text is behind the <em>Science<\/em> paywall, but the abstract and editor\u2019s summary capture the core advance:<\/strong> <\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>using the clumped- isotope signature of N\u2082 (\u0394\u2083\u2080) as a natural tracer for microbial nitrogen removal.<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Journal:<\/strong> <a href=\"https:\/\/phys.org\/journals\/science\/\">Science<\/a> ,Vol. 394, Issue 6820, pp. 207- 211, 8 October 2026<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>DOI:<\/strong> <a href=\"https:\/\/dx.doi.org\/10.1126\/science.aei0940\" target=\"_blank\" rel=\"noopener\">10.1126\/science.aei0940<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Provided:<\/strong> <a href=\"https:\/\/phys.org\/partners\/university-of-california---santa-barbara\/\">University of California &#8211; Santa Barbara<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Authors:<\/strong> <a href=\"https:\/\/www.science.org\/doi\/10.1126\/science.aei0940?referrer=https%3A%2F%2Fphys.org%2F#con1\">Jiarui Liu<\/a>, <a href=\"https:\/\/www.science.org\/doi\/10.1126\/science.aei0940?referrer=https%3A%2F%2Fphys.org%2F#con2\">David L. Valentine<\/a><a href=\"https:\/\/orcid.org\/0000-0001-5914-9107, Annie Bourbonnais\">, Annie Bourbonnais<\/a><a href=\"https:\/\/orcid.org\/0000-0001-7247-5230, Dale T. Andersen https:\/\/orcid.org\/0000-0001-8827-1259, Daniele Bianchi https:\/\/orcid.org\/0000-0002-6621-0858, Grace Brown https:\/\/orcid.org\/0000-0002-9934-385X, M. Bayani Cardenas https:\/\/orcid.org\/0000-0001-6270-3105, Daniel Fillion, Claudia Frey https:\/\/orcid.org\/0000-0002-3544-3800, Kelsey M. Gosselin, Aoshuang Ji https:\/\/orcid.org\/0000-0002-9152-1287, Franklin S. Kinnaman, Denis Lacelle https:\/\/orcid.org\/0000-0002-6691-8717, Moritz F. Lehmann https:\/\/orcid.org\/0000-0003-0626-5942, Katelyn McPaul https:\/\/orcid.org\/0000-0001-9941-2969, James Mullahoo https:\/\/orcid.org\/0000-0002-5469-4066, Victoria J. Orphan https:\/\/orcid.org\/0000-0002-5374-6178, Andr\u00e9 Pellerin https:\/\/orcid.org\/0000-0003-3588-8372, Elen Reji, Elizabeth D. Swanner https:\/\/orcid.org\/0000-0001-9507-0893, Tina Treude https:\/\/orcid.org\/0000-0001-6366-286X, Alan M. Seltzer https:\/\/orcid.org\/0000-0003-2870-1215, and Edward D. Young\">, Dale T. Andersen, Daniele Bianchi, Grace Brown, M. Bayani Cardenas, Daniel Fillion, Claudia Frey, Kelsey M. Gosselin, Aoshuang Ji, Franklin S. Kinnaman, Denis Lacelle, Moritz F. Lehman, Katelyn McPa , James Mullahoo, Victoria J. Orph, Andr\u00e9 Pellerin, Elen Reji, Elizabeth D. Swanner, Tina Treude, Alan M. Seltzer, and Edward D. Young<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Scientists have developed a new way to track microbial nitrogen removal using the rare pairing of two heavy nitrogen- 15 atoms in N\u2082 gas molecules. <\/p>\n<p>Clumped isotope theory (or clumped- isotope geochemistry) studies the tendency of rare, heavy isotopes to bond preferentially with one another within molecules, rather than being randomly distributed among the more common light isotopes.<\/p>\n","protected":false},"author":121246920,"featured_media":478034,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","advanced_seo_description":"Discover how rare nitrogen-15 isotopes help scientists track microbial nitrogen removal in our vital nitrogen cycle.","jetpack_seo_html_title":"Unlocking the Nitrogen Cycle: Rare Isotope Tracking Tech","jetpack_seo_noindex":false,"jetpack_seo_schema_type":"","_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_wpcom_ai_launchpad_first_post":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691846216,691846213,691846212,691846217,691831085,691846219,691846218,691846214,691846215],"class_list":["post-478033","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-clumped-isotope","tag-clumping","tag-dead-zones","tag-earths-nitrogen-cycle","tag-microbes","tag-n-gas","tag-nitrogen-compounds","tag-nitrogen-14","tag-nitrogen-15","fallback-thumbnail"],"jetpack_publicize_connections":[],"jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-20md","jetpack-related-posts":[{"id":288704,"url":"https:\/\/climatescience.press\/?p=288704","url_meta":{"origin":478033,"position":0},"title":"Climate Alarmists Ignore Nitrogen\u00a0Deficiency","author":"uwe.roland.gross","date":"11\/26\/2023","format":false,"excerpt":"From Science Matters By\u00a0Ron Clutz From the Advanced Science Research Center, GC\/CUNY\u00a0Earth Has Too Much Nitrogen \u2013 and Too Little Nitrogen \u2013 at the Same Time.\u00a0 Excerpts in italics with my bolds Multi-institutional research team finds decliningnitrogen availability in a nitrogen-rich world. Since the mid-20th century,\u00a0research and discussion have focused\u2026","rel":"","context":"In \"CO2\"","block_context":{"text":"CO2","link":"https:\/\/climatescience.press\/?tag=co2"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/0shutterstock_1282821727-scaled-1.jpg?fit=1141%2C1200&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/0shutterstock_1282821727-scaled-1.jpg?fit=1141%2C1200&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/0shutterstock_1282821727-scaled-1.jpg?fit=1141%2C1200&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/0shutterstock_1282821727-scaled-1.jpg?fit=1141%2C1200&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/11\/0shutterstock_1282821727-scaled-1.jpg?fit=1141%2C1200&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":455004,"url":"https:\/\/climatescience.press\/?p=455004","url_meta":{"origin":478033,"position":1},"title":"Alice in Hydrogen Land","author":"uwe.roland.gross","date":"07\/10\/2026","format":false,"excerpt":"At a shopping mall or amusement park one can see vendors selling balloons filled with Helium. Kids love them and dance around trailing their balloons, which float above them. From time to time some kid accidentally lets go and you see the balloon soaring high into the sky, to the\u2026","rel":"","context":"In \"hydrogen\"","block_context":{"text":"hydrogen","link":"https:\/\/climatescience.press\/?tag=hydrogen"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-Alice-in-Hydrogen-Land.jpg?fit=1168%2C784&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-Alice-in-Hydrogen-Land.jpg?fit=1168%2C784&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-Alice-in-Hydrogen-Land.jpg?fit=1168%2C784&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-Alice-in-Hydrogen-Land.jpg?fit=1168%2C784&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/07\/0-Alice-in-Hydrogen-Land.jpg?fit=1168%2C784&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":259650,"url":"https:\/\/climatescience.press\/?p=259650","url_meta":{"origin":478033,"position":2},"title":"How a drought affects trees depends on what\u2019s been holding them back","author":"uwe.roland.gross","date":"05\/30\/2023","format":false,"excerpt":"\u201cDroughts are leading to widespread tree mortality across the globe,\u201d Dudney said, \u201cwhich can accelerate global warming.\u201d\u00a0","rel":"","context":"In \"Climate change\"","block_context":{"text":"Climate change","link":"https:\/\/climatescience.press\/?tag=climate-change"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/0whitebark-pine-6-credit-Quinn-Lowrey-2048x1536-1.jpg?fit=1200%2C900&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/0whitebark-pine-6-credit-Quinn-Lowrey-2048x1536-1.jpg?fit=1200%2C900&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/0whitebark-pine-6-credit-Quinn-Lowrey-2048x1536-1.jpg?fit=1200%2C900&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/0whitebark-pine-6-credit-Quinn-Lowrey-2048x1536-1.jpg?fit=1200%2C900&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/05\/0whitebark-pine-6-credit-Quinn-Lowrey-2048x1536-1.jpg?fit=1200%2C900&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":333324,"url":"https:\/\/climatescience.press\/?p=333324","url_meta":{"origin":478033,"position":3},"title":"Central Italy Was 3-4\u00b0C Warmer Than Today About 10,000 to 12,000 Years Ago","author":"uwe.roland.gross","date":"06\/20\/2024","format":false,"excerpt":"In a new study, scientists use the new \u201costracod-clumped isotope thermometer\u201d to reconstruct a much warmer Late Pleistocene\/Early Holocene Mediterranean climate.","rel":"","context":"In \"220-230 ppm range\"","block_context":{"text":"220-230 ppm range","link":"https:\/\/climatescience.press\/?tag=220-230-ppm-range"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/06\/037225813515_ba707da1a3_b.jpg?fit=1024%2C683&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/06\/037225813515_ba707da1a3_b.jpg?fit=1024%2C683&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/06\/037225813515_ba707da1a3_b.jpg?fit=1024%2C683&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/06\/037225813515_ba707da1a3_b.jpg?fit=1024%2C683&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":421351,"url":"https:\/\/climatescience.press\/?p=421351","url_meta":{"origin":478033,"position":4},"title":"Oh Noes! Climate Change is Messing with the Nitrogen Cycle","author":"uwe.roland.gross","date":"01\/14\/2026","format":false,"excerpt":"From the \u201cridiculous press releases I never bothered to finish reading\u201d department comes this gem of a doomsday paper. The press release looks like it written with AI, one wonders if the study was too. \u2013 Anthony","rel":"","context":"In \"Bad Science\"","block_context":{"text":"Bad Science","link":"https:\/\/climatescience.press\/?tag=bad-science"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/AQO_nM4AkzXY336PQP1kZV2xV9ycZPIPJ9mZ6s2yZrDCYePfoeQ05fMNAQhEtscMnL52Rc2E-Q6Np4vc9ApbYkEWvez0PVoDpO5fZIGr4A4DDRF55CPt3r8lFWQYYQ4Z9FS2yR6HfNH8FvrsrFqKVKIO1KWDlw.jpeg?fit=1200%2C1200&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/AQO_nM4AkzXY336PQP1kZV2xV9ycZPIPJ9mZ6s2yZrDCYePfoeQ05fMNAQhEtscMnL52Rc2E-Q6Np4vc9ApbYkEWvez0PVoDpO5fZIGr4A4DDRF55CPt3r8lFWQYYQ4Z9FS2yR6HfNH8FvrsrFqKVKIO1KWDlw.jpeg?fit=1200%2C1200&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/AQO_nM4AkzXY336PQP1kZV2xV9ycZPIPJ9mZ6s2yZrDCYePfoeQ05fMNAQhEtscMnL52Rc2E-Q6Np4vc9ApbYkEWvez0PVoDpO5fZIGr4A4DDRF55CPt3r8lFWQYYQ4Z9FS2yR6HfNH8FvrsrFqKVKIO1KWDlw.jpeg?fit=1200%2C1200&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/AQO_nM4AkzXY336PQP1kZV2xV9ycZPIPJ9mZ6s2yZrDCYePfoeQ05fMNAQhEtscMnL52Rc2E-Q6Np4vc9ApbYkEWvez0PVoDpO5fZIGr4A4DDRF55CPt3r8lFWQYYQ4Z9FS2yR6HfNH8FvrsrFqKVKIO1KWDlw.jpeg?fit=1200%2C1200&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/01\/AQO_nM4AkzXY336PQP1kZV2xV9ycZPIPJ9mZ6s2yZrDCYePfoeQ05fMNAQhEtscMnL52Rc2E-Q6Np4vc9ApbYkEWvez0PVoDpO5fZIGr4A4DDRF55CPt3r8lFWQYYQ4Z9FS2yR6HfNH8FvrsrFqKVKIO1KWDlw.jpeg?fit=1200%2C1200&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":441323,"url":"https:\/\/climatescience.press\/?p=441323","url_meta":{"origin":478033,"position":5},"title":"NASA\u2019s Curiosity Finds Organic Molecules Never Seen Before on Mars","author":"uwe.roland.gross","date":"04\/25\/2026","format":false,"excerpt":"NASA\u2019s Curiosity rover has detected the most diverse collection of organic molecules ever found on Mars, including seven carbon-containing compounds never previously identified on the Red Planet. The findings, published April 21, 2026, in Nature Communications, come from analysis of a rock sample drilled in 2020 at the \"Mary Anning\u2026","rel":"","context":"In \"21 organic molecules\"","block_context":{"text":"21 organic molecules","link":"https:\/\/climatescience.press\/?tag=21-organic-molecules"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-NASAs-Curiosity-Finds-Organic-Molecules-Never-Seen-Before-on-Mars.jpg?fit=784%2C1168&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-NASAs-Curiosity-Finds-Organic-Molecules-Never-Seen-Before-on-Mars.jpg?fit=784%2C1168&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-NASAs-Curiosity-Finds-Organic-Molecules-Never-Seen-Before-on-Mars.jpg?fit=784%2C1168&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/04\/0-NASAs-Curiosity-Finds-Organic-Molecules-Never-Seen-Before-on-Mars.jpg?fit=784%2C1168&ssl=1&resize=700%2C400 2x"},"classes":[]}],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2026\/10\/0-Rare-Atomic-Pair-Reveals-Where-Earths-Nitrogen-Really-Goes.jpg?fit=1168%2C784&ssl=1","_links":{"self":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/478033","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/users\/121246920"}],"replies":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=478033"}],"version-history":[{"count":36,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/478033\/revisions"}],"predecessor-version":[{"id":478071,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/posts\/478033\/revisions\/478071"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=\/wp\/v2\/media\/478034"}],"wp:attachment":[{"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=478033"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=478033"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/climatescience.press\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=478033"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}