An international research team led by the Geomar Helmholtz center for Ocean Research Kiel has discovered a globally unique system in the seabed in front of the Coast of Papua New Guinea.
During their expedition aboard the Sonne research container, they met the “Karambusel” field, where two processes are produced simultaneously: the release of hot hydrothermal fluids and unusually high amounts of methane and other hydrocarbons.
This combination makes the system unique worldwide.
It is at a depth of around 1,300 meters on a conical submarine mountain flank in the Western Pacific, in front of the island of Lihir in Papua New Guinea.
Hydrothermal vents and methane leaks generally occur in different parts of the sea. In this case, however, they are very close due to the unique geology of the conical submarine mountain, where the thick sediment layers containing organic material are under the volcanic structure. Ascending magma heats these layers, generating methane and other hydrocarbons. At the same time, this magmatic heat also drives fluids rich in minerals up, where they emerge as hot vents at the bottom of the sea.
Both fluids, hot water from depth and colder gases rich in sediments methane, travel along the same roads to the surface. Consequently, hot liquid and cold gas bubble from the seabed just a few centimeters away.
This direct neighborhood creates a completely new hybrid environment, which provides a habitat for an extremely diverse range of animals. The dense fields of the mussel batimodiolus, tube worms, shrimp, amphipods and purple sea cucumbers cover the rocks.
Dr. Philipp Brandl, marine geologist at the Geomar Helmholtz center for Ocean Research Kiel, said: “No one really expected to find a hydrothermal field here, and much less one that is so exceptional.” Although the previous expeditions had indicated a lower hydrothermal activity, the field remained without detecting during several research cruises. It was only through the use of the Kiel 6000 ROV that the peculiarities of this underwater landscape were revealed. “It was a real surprise,” says Brandl, “especially for those of us who had worked in this area several times.”
Due to the abundance of mussels, the scientists, together with the local observer Stanis Konabe of the University of Papua New Guinea, called the ‘Karambusel’ field. In Tok Pisin’s local language, this means ‘mussel’.
The unusual composition of gas in the Karambusel field influences the communities of life and geological characteristics. The emitted methane is highly concentrated, greater than 80%, while hot fluids increase from magma simultaneously, creating unique chemical conditions in the subsoil. Metals such as gold and silver, along with elements such as arsenic, antimony and mercury, are deposited in the rock. Therefore, the area carries the brands of a high temperature previous phase that involves precious metals, along with the coldest and most current activity.
Despite its unique geology and biology, this site is under threat. Mining is already taking place in the region, for example, in the Ladolam Gold Mine in Lihir, where waste and waste are discharged into the sea. There are also exploration licenses for minerals and hydrocarbons in the seabed. This endangers fragile habitat and its highly specialized fauna.
Therefore, researchers ask for a more urgent study, directed marine planning and effective protection measures to preserve this extraordinary ecosystem. Brandl: “We have discovered an unexpected treasure of biodiversity in the Karambusel field that must be protected before economic interests destroy it.”