While many young volcanoes have active hydrothermal systems, there is little understanding of the long-term (>decadal time-scale) evolution of hydrothermal systems that are still active today. New research published this month in Nature Communications reveals the hydrothermal history of Santorini caldera, Greece, using a combination of geological and genomic evidence from marine sediment cores to determine the paleoenvironmental and biogeochemical history of the system. Analysis reveals vigorous hydrothermal activity and metal fluxes in the Santorini caldera for ~1100 years, between two major volcanic eruptions. The work provides new perspectives on the long-term evolution of submarine hydrothermal systems and new insights into the interplay between volcanism, hydrothermalism, and submarine life.
New research published on 4th August in Nature Communications has revealed the hydrothermal history of Santorini caldera, Greece, shining light on the evolution of a system which has, until now, been poorly understood. The study, conducted by an international team of scientists, used a sequence of sediments collected during International Ocean Discovery Program (IODP) Expedition 398.
The team, led by Sofia Della Sala from Oxford’s Department of Earth Sciences, used a marine sediment core of ~150m – spanning ~3600 years’ history – to screen for hydrothermal metals and extract microbial samples. They were able to identify volcanic layers and link metal fluxes and microbial signatures to pre or post eruption sediments. During a window between the Late Bronze Age ‘Minoan’ eruption of ~1630 BCE and the 726 CE eruption, hydrothermally-derived trace metals were found to be significantly enriched over background levels. Microbial DNA analysis also identified elevated metal-resistance genes in samples, indicating an adaptive response to hydrothermal stressors. This combination of geological and genomic evidence points to a prolonged period of vigorous hydrothermal activity for ~1100 years.
The results indicate that Santorini had a prolonged and heightened hydrothermal past, with higher metal fluxes and more microbial metal resistance than we see in the present-day hydrothermal system in the region.
Various papers have alluded to Santorini’s hydrothermal past, and hypothesised about the state of the system just after the Minoan eruption. Data from IODP Expedition 398 has finally allowed this history to be investigated, which in turn allows us to further explore the relationships between hydrothermal systems and wider geological processes such as ore deposit formation and biogeochemical cycling, as well as submarine life.
- Lead author Sofia della Sala
You can watch how this fieldwork was conducted in the video 'Life in the field: Exploring the Sea Floor' created by Oxford Sparks or listen to the podcast How can robots investigate underwater volcanoes?
The study 'A prolonged hydrothermal past at Santorini Caldera revealed by sedimentary trace metal and microbial signatures.' is available in Nature Commnications at https://doi.org/10.1038/s41467-026-75931-8
