Rhodoliths as Daily Resolution Paleotemperature Archives in the Red Sea

A team of researchers led by KAUST graduate Lena Li with KAUST faculty Maggie Johnson recently published a paper entitled: "Rhodoliths can act as daily resolution paleotemperature archives in the Red Sea". KVL and scientist Ronell Sicat were acknowledged for providing facilities support and expertise in image processing.

The study shows that rhodoliths — free‑living, calcified red algae found widely on the seafloor—can serve as highly detailed natural “thermometers” of past ocean conditions. The researchers developed a new method combining chemical markers, micro‑CT imaging, and advanced time‑alignment techniques to reconstruct daily seawater temperatures from the complex growth patterns of a single rhodolith collected in the Red Sea, producing a continuous 133‑day record. By integrating data from multiple growth directions and chemical indicators, their approach closely matched real temperature measurements, demonstrating much greater accuracy than previous methods. Overall, the work provides proof of concept that rhodoliths can deliver high‑resolution climate records, which could help scientists better understand short‑term temperature variability and improve predictions of how marine ecosystems respond to ongoing ocean warming. 

This subset of the paper's Fig. 2 shows a micro-CT image of a rhodolith sample (d) with the curved line perpendicular to the growth line, and a light microscope image (f) showing a 2mm growth in the sample in a span of four months. Please note that this figure is directly from the original published paper. Access it here.

KVL's visualization scientist Dr. Ronell Sicat supported Lena Li in image processing and finding ways to track the growth line. KVL also provided free access to Avizo software for data visualization and analysis and a powerful workstation. KVL's contribution is acknowledged in the paper.