Deep-Sea Hotspot Discovered Off Papua New Guinea

Off the coast of Papua New Guinea, scientists have made a groundbreaking discovery of a previously unknown hydrothermal field located about 1,300 meters deep on the slope of Conical Seamount, near the island of Lihir.

This unique site, named 'Karambusel' after the dense population of Bathymodiolus mussels, exhibits an extraordinary combination of hot hydrothermal fluids and large quantities of methane escaping from the sediments, a phenomenon never documented before.

Dr. Philipp Brandl, marine geologist at the GEOMAR Helmholtz Centre for Ocean Research Kiel and chief scientist on the SONNE expedition SO299 DYNAMET, emphasized that this hydrothermal field is exceptional, stating, "We essentially have a hot vent bubbling right next to a cool gas seep." The discovery was made possible through the deployment of the ROV Kiel 6000, which revealed features that had previously gone unnoticed despite earlier research missions in the area.

The hybrid system of hot and cool vents results from thick layers of organic-rich sediment beneath the volcanic structure, where rising magma heats these sediments, generating methane and other hydrocarbons.

This unique arrangement creates an entirely new deep-sea habitat that supports a diverse array of life, including tube worms, shrimp, amphipods, and vibrant purple sea cucumbers. Dr. Brandl noted, "In places, you couldn't see a single patch of rock because everything is so densely populated," indicating that some species in this area may still be undiscovered.

The unusual mixture of gases at Karambusel, with methane levels exceeding 80 percent, also influences the geological characteristics of the vent field, contributing to the accumulation of precious metals like gold and silver, alongside arsenic, antimony, and mercury.

Despite its ecological significance, the Karambusel site faces threats from nearby mining activities, such as the Ladolam gold mine, which discharges waste material into the ocean. Additionally, there are exploration licenses for seafloor minerals and hydrocarbons that pose risks to the fragile ecosystem.

The research team has called for further investigation and the implementation of protective measures, with Dr. Brandl stating, "We have discovered an unexpected treasure trove of biodiversity in the Karambusel field that needs to be protected before economic interests destroy it." The findings were published in Scientific Reports, highlighting the need for marine spatial planning to safeguard this remarkable deep-sea hotspot.