GEOTRACES Sesions at Goldschmidt 2026

Dear colleagues,

We would like to draw your attention to the following GEOTRACES sessions at Goldschmidt 2026 (12-17 July 2026, Montréal, Quebec, Canada).

The abstract submission deadline is 26 February 2026.

**GEOTRACES and GEOTRACES related sessions**

12c – The Role of Boundaries Across Scales in Shaping Marine Trace Element Distributions
https://conf.goldschmidt.info/goldschmidt/2026/goldschmidt/2026/meetingapp.cgi/Session/8629

Description:
Trace elements and isotopes (TEIs) play essential roles in the ocean, serving not only as micronutrients, but useful tools for better understanding marine biogeochemistry. Their distributions are strongly influenced by boundaries – regions where physical, chemical, and biological gradients intersect to control redox states, speciation, and particle reactivity. This boundary concept encompasses large-scale interfaces (e.g. atmosphere-ocean, seafloor-ocean, land-ocean), and biogeochemical gradients, including redox fronts, Oxygen Minimum Zone (OMZ) – oxygenated transitions, particle-seawater microenvironments, and organism-associated microscale habitats (e.g., phycospheres, benthic ecosystems), where intense exchange is mediated by chemical gradients and biological activity. At large-scale ocean interfaces, inputs from natural and anthropogenic pathways, rapid transformations (oxidation, complexation, adsorption), and burial occur, thereby modulating oceanic TEI residence times. Within the water column, sharp redox boundaries (e.g., at OMZs) regulate the solubility, mobility, and bioavailability of several TEIs (e.g., Fe, Co). At the microscale, particle surfaces and organic exudates define reactive microenvironments that control adsorption-desorption dynamics and trace metal speciation. Additionally, the boundary between seawater and microorganism cells control metabolic processes and the internal cycle of TEIs. Recognizing this spectrum of boundaries highlights the interconnected pathways shaping TEI distributions across spatial scales, helping to disentangle the importance of bottom-up versus top-down controls. Integrating processes from global interfaces to microscale gradients is thus essential for predicting how marine TEI cycling responds to climate change and anthropogenic perturbations. This session welcomes field observations, laboratory experiments, and modelling studies to gain further understanding on how different ocean “boundaries” control TEI distributions.

Conveners:
Zhouling Zhang, GEOMAR Helmholtz Centre for Ocean Research Kiel
Nolwenn Lemaitre, Laboratoire d’Etudes en Géophysique et Oceanographie Spatiales
Ryan Cloete, Stellenbosch University
Anh Le-Duy Pham, University of California, Los Angeles
Wen-Hsuan Liao, National Cheng Kung University

12j – Applications of naturally-occurring radioactive isotopes and constant flux proxies in seawater and marine sediments
https://conf.goldschmidt.info/goldschmidt/2026/goldschmidt/2026/meetingapp.cgi/Session/8897

Description:
Naturally occurring radioisotopes and constant flux proxies have revolutionized our ability to quantify and reconstruct vertical particle settling and sediment deposition rates across a variety of modern and past oceanographic conditions. These geochemical tracers, including U-series isotopes, extraterrestrial helium-3, meteoric beryllium-10, and other isotopes with predictable production rates or input functions, have thus enabled refined investigation into dynamic processes such as aerosol deposition, continental input, ocean circulation strength, water mass changes, hydrothermal metal fluxes, biologic productivity and carbon export. Yet, as constant flux proxies become more widely measured, fundamental questions remain regarding when, where, and how the mechanics of each proxy system may or may not work as assumed and what information can be inferred when distinct proxies yield disparate results.
This session invites observational and modeling contributions regarding recent applications, insights, and identified complications of naturally occurring radioisotopes and constant flux proxies applied in modern or paleoceanographic environments.

Conveners:
Kassandra Costa, Woods Hole Oceanographic Institution
Jennifer L Middleton, Columbia University
Frank Pavia, University of Washington
Kai Deng, Tongji University

09k – Integrating Biological and Geochemical Perspectives on Trace Metal(loid) Transformations Across Ecosystems
https://conf.goldschmidt.info/goldschmidt/2026/meetingapp.cgi/Session/9054

Description:
The biogeochemical cycling of trace metal(loid)s in both terrestrial and aquatic environments plays a central role in regulating ecosystem productivity, elemental speciation, and environmental health. Interactions among microbes, minerals, and dissolved species control the transformation, bioavailability, and isotopic signatures of key trace elements, influencing complex biogeochemical feedbacks from local to global scales. Importantly, trace metal(loid) transformations are tightly coupled to the cycling of carbon, sulfur, and other nutrients, linking redox dynamics and microbial metabolism/detoxification processes to broader ecosystem function. This session unites studies that bridge biological and geochemical perspectives on trace metal(loid) cycling across redox gradients and physical scales—from laboratory experiments to field observations and modeling. We invite contributions examining mineral dissolution and precipitation, redox transformations, the formation of reactive organo-mineral complexes, and methylation–demethylation reactions with a focus on elements including, but not limited to, mercury, uranium, arsenic, selenium, manganese, and iron. We particularly welcome approaches integrating isotopic, spectroscopic, imaging, -omics, biosensor, and modeling techniques to advance molecular understanding of trace element dynamics. By linking microbial and geochemical perspectives, this session aims to provide new mechanistic insights into the speciation and environmental fate of trace metal(loid)s in societally important ecosystems including marine waters, groundwater aquifers, agricultural soils (such as rice paddies), and mining-impacted environments.

Conveners:
Matthew Reid, Cornell University
Tim M. Conway, University of South Florida
Jacqueline Gerson, Cornell University
Phoebe Lam, University of California Santa Cruz
Alexandre Poulain, University of Ottawa
Yeala Shaked, Hebrew University

To submit an abstract please follow the instructions available here: 
https://conf.goldschmidt.info/goldschmidt/2026/cfp.cgi

An updated list of GEOTRACES relevant sessions at Goldschmidt 2026 will be available at: https://www.geotraces.org/event/goldschmidt-2026/

If you wish your session to be included in this list, please send an e-mail to elena.masferrer-dodas@univ.tlse3.fr

Best regards,
GEOTRACES IPO