X-ray methods to investigate nutrient cycling in the subsurface

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dc.contributor.authorBone, Sen_AU
dc.contributor.authorAristilde, Len_AU
dc.contributor.authorBargar, Jen_AU
dc.contributor.authorKlein, ARen_AU
dc.contributor.authorCliff, JBen_AU
dc.date.accessioned2023-04-18T02:52:20Zen_AU
dc.date.available2023-04-18T02:52:20Zen_AU
dc.date.issued2021-12-18en_AU
dc.date.statistics2023-02-02en_AU
dc.description.abstractX-ray methods provide unique insight into the biogeochemical cycling of nutrients, such as C, P and Ca, in the subsurface, particularly when nutrient availability is mediated by interactions with the solid phase. For instance, mineral phases in the sediments may sorb nutrients, mediating their availability to microbes. In other instances, minerals can catalyze nutrient transformations. In this talk, I will give two examples of how soft and tender X-ray spectroscopies can be utilized to examine critical steps in nutrient cycling. In the first example, Ca speciation in the subsurface is investigated using a combination of scanning transmission X-ray microscopy (STXM) and tender X-ray microprobe analysis. Soils and sediments host large stores of organic carbon which can be released to the atmosphere upon mineralization. Ca may play a key role in preventing organic matter (OM) mineralization by promoting mineral sorption. Although it has long been recognized that Ca forms cation bridges that link negatively charged organic and mineral functional groups, there is little direct experimental observation of this, which is necessary for a molecular-scale, predictive understanding. We examined whether OM-Ca was co-associated with specific minerals, and with what OM types Ca was associated using nano secondary ion mass spectrometry (NanoSIMS) and STXM. The Ca speciation was probed further using (micro-) X-ray absorption near edge structure (XANES) spectroscopy. In the second example, I will discuss how XANES spectroscopy can be used to elucidate abiotic transformation of organic P to inorganic P, rendering it bioavailable. Organic P species, in particular phosphate esters such as those found in ribonucleotides, can comprise a significant fraction of total P in soils and sediments. P K-edge XANES spectroscopy was utilized to monitor dephosphorylation of ribonucleotides by ferrihydrite, and helped to elucidate how the extent of dephosphorylation was related to organic P type.en_AU
dc.identifier.articlenumberB55I-1303en_AU
dc.identifier.booktitleAGU Fall Meeting Abstractsen_AU
dc.identifier.citationBone, S., Aristilde, L., Bargar, J., Klein, A., & Cliff, J. B. (2021). X-ray methods to investigate nutrient cycling in the subsurface. Invited presentation to the AGU Fall Meeting 2021, New Orleans, Louisiana and Online, 13-17 December 2021. In AGU Fall Meeting Abstracts (Vol. 2021, B55I-1303). Retrieved from: https://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/804629en_AU
dc.identifier.conferenceenddate17 December 2021en_AU
dc.identifier.conferencenameAGU Fall Meeting 2021en_AU
dc.identifier.conferenceplaceNew Orleans, Louisiana and Onlineen_AU
dc.identifier.conferencestartdate13 December 2021en_AU
dc.identifier.urihttps://agu.confex.com/agu/fm21/meetingapp.cgi/Paper/804629en_AU
dc.identifier.urihttps://apo.ansto.gov.au/dspace/handle/10238/14893en_AU
dc.identifier.volume2021en_AU
dc.language.isoenen_AU
dc.publisherAmerican Geophysical Union (AGU)en_AU
dc.subjectX-ray spectroscopyen_AU
dc.subjectNutrientsen_AU
dc.subjectUndergrounden_AU
dc.subjectMineralsen_AU
dc.subjectCarbonen_AU
dc.subjectPhosphorusen_AU
dc.subjectCalciumen_AU
dc.subjectSedimentsen_AU
dc.subjectOrganic matteren_AU
dc.subjectSorptionen_AU
dc.titleX-ray methods to investigate nutrient cycling in the subsurfaceen_AU
dc.typeConference Presentationen_AU
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