New project: A novel geochemical proxy to reconstruct past glacier melt

A new iC3 research project due to launch in September 2026 will develop a novel geochemical proxy to reconstruct past glacier melt in key Arctic environments. 

Led by MSCA postdoctoral fellow Inda Brinkmann, the project “GMPro” (Glacier Melt Proxy) will deliver the first high-resolution reconstruction of total glacier melt during past warm periods, on the basis of barium-to-calcium (Ba/Ca) ratio in benthic foraminifera. 

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Known unknowns in paleoclimatology 

The Arctic is warming at an unprecedented rate, leading to rapid glacier retreat and accelerated melting of ice sheets.  

This has far-reaching consequences on the Earth’s sea level, ocean geochemistry and global warming trajectories. Still, climate projections often exclude glacier melt dynamics due to the uncertainty surrounding their long-term behavior, resulting in wide-ranging sea-level rise projections—from mere decimeters to several meters by 2300. 

Inda’s project aims to close this gap by delivering much-needed empirical data—on geological and modern time scales—to enhance model accuracy and climate forecasting.

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Filling a critical knowledge gap

The GMPro project introduces a geochemical approach using barium-to-calcium ratios (Ba/Ca) in benthic foraminifera to trace total glacial discharge, including subglacial and surface melt. This method capitalizes on terrestrial input, such as rivers or marine-terminating glaciers, representing the main source of barium to the ocean. 

These land-to-sea fluxes may be recorded as changes in the chemical composition of foraminiferal calcium carbonates in coastal marine sediments—and thereby provide a quantifiable signal of melt intensity through time. 

Inda’s project will resolve glacier melt histories, improve climate model validation by extending proxy-based records beyond the instrumental period, and generate high-resolution Arctic paleo-data to refine predictions of future glacier behavior.

Credit photo: Lukas Taenzer

From Svalbard to Greenland 

Inda’s work will focus on two key Arctic fjords, Kongsfjorden in Svalbard and Sermilik Fjord in Greenland, and combine modern proxy calibration studies with paleo approaches. 

To groundtruth the new proxy, Inda will focus on modern water and sediment samples from Kongsfjorden to trace the biogeochemical pathways of barium from ‘source to sink’ in a seasonal approach. This will establish a robust baseline for interpreting past glacier melt.

The project will then validate the proxy against established glacial indicators. Focusing on records of the past 1,000 years it will be possible to test whether Ba/Ca faithfully tracks glacial melt through key climate shifts, including the Little Ice Age and modern warming.

Finally, by applying the new Ba/Ca proxy to mid-Holocene sediment cores from Svalbard and Greenland, Inda will reconstruct how Arctic glaciers responded to the last major natural warming event (9500–5500 years BP). This will provide crucial insights into how current warming trends may play out in the future.

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Joining the iC3 team

Inda Brinkmann has extensive experience in benthic foraminifera research, with a strong focus on biogeochemical approaches and coastal marine environments. Currently she is based at the Centre of Palaeogenetics at Stockholm University. In Tromsø, she will be supervised by Jochen Knies and Mohamed Ezat. The project includes a secondment as GEUS, where she will work with marine geologist Camilla S. Andresen.

Inda’s work is funded through an MSCA postdoctoral fellowship. Reviewers awarded her research proposal a stellar score of 97.6%. 

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If you are interested in joining the iC3 Polar Research Hub as a postdoc, please get in touch. We currently still have 10 MSCA postdoc opportunities available.