A Bold Discovery: Milos Hosts a Rich New Network of Hydrothermal Vents—and the Implications Are Bigger Than They Look.
Three major vent clusters emerge along Milos’s active fault lines—Aghia Kiriaki, Paleochori–Thiorychia, and Vani—forming a pronounced pattern tied to the island’s geological framework. These clusters sit along faults that belong to a broad tectonic trough known as the Milos Gulf–Fyriplaka graben, a region where the seafloor has subsided to depths reaching roughly 230 meters. The tight alignment of venting sites with these structural features underscores a direct link between tectonic activity and where hydrothermal fluids reach the seafloor.
“We didn’t anticipate finding such an expansive field of gas flares off Milos,” remarked Solveig I. Bühring, the study’s senior author and a scientist with MARUM – Center for Marine Environmental Sciences at the University of Bremen. She led the M192 expedition during which the vents were first detected. “The moment we peered through the ROV cameras, we were spellbound by their variety and beauty—from shimmering, boiling plumes to thick microbial mats coating the chimneys.”
Paraskevi Nomikou, the study’s first author from the National and Kapodistrian University of Athens, notes that the arrangement of vent clusters mirrors the island’s tectonic fabric:
“Our data clearly show that the gas flares align with Milos’s major fault systems,” Nomikou explained. “Different fault zones govern distinct vent clusters, particularly where several faults intersect. These tectonic structures strongly regulate how and where hydrothermal fluids ascend to the seafloor.”
The research demonstrates that ongoing faulting and dynamic geological processes have actively sculpted the evolution of these vent fields. Milos thus emerges as one of the Mediterranean’s most valuable natural laboratories for exploring the interplay between tectonics, volcanism, and hydrothermal activity.
These findings also feed into MARUM’s Cluster of Excellence, “The Ocean Floor – Earth’s Uncharted Interface.” Plans are in place for a follow-up expedition that will include Milos, the Kolumbo submarine volcano near Santorini, and Nisyros. The project represents a close collaboration among Greek and German institutions, including the National and Kapodistrian University of Athens, MARUM – University of Bremen, Friedrich-Alexander-Universität Erlangen-Nürnberg, ICBM – Institute for Chemistry and Biology of the Marine Environment Oldenburg, and Constructor University Bremen.
