Image of the month September
Black smokers in the Niua South Volcano
The image of the month September shows a so-called black smoker in the Niua South underwater volcano between Tonga and Samoa. The volcano’s caldera contains numerous hydrothermal vents. Black smokers are chimneys up to 30 meters high, consisting of massive sulfides, which can be found in the deep sea at water depths between 1000 and more than 5000 meters. They occur in volcanic active zones at submarine plate boundaries and form where water with a temperature of up to 400 degrees Celsius comes from the seabed.
These black smokers are formed when seawater seeps through cracks in the seabed into the earth’s crust near magma chambers, where it is heated and rises again, dissolving elements such as copper, zinc, iron, sulphur, gold and silver from the rock. These minerals are deposited on the seabed in the form of sulfide hills, chimneys or sediments.
Although extremely high temperatures prevail inside the chimneys, ecosystems have developed which are perfectly adapted to these very special conditions. A unique community of species with a dense population of highly specialized organisms live in these areas.
In 1977, researchers first discovered such structures through the tiny porthole of the US submersible ALVIN at the bottom of the Eastern Pacific. Meanwhile more than 390 hydrothermal fields are known in all oceans of the world. They show enormous differences in the size of the deposits.
Through the years, expeditions to black smokers have developed noticeably. Today, autonomous deep-sea drones and cable-controlled robots are sent to the hot vents. In spring 2016, the US Schmidt-Ocean Institute used the Canadian deep-sea robot ROV ROPOS for its "Virtual Vents" expedition. The Institute’s research vessel FALKOR brought the research team led by Dr. Tom Kwasnitschka from GEOMAR to the 40,000m² hydrothermal field in the caldera of the Niua underwater volcano. The image of the month September was taken on this expedition. The aim of the voyage was a precise measurement of the field in order to develop a 3D computer model in the further course of the expedition. While the ROV ROPOS carried out the measurements, not only the nine-member research team on board of the FALKOR was able to follow the camera images live. With the help of state-of-the-art satellite technology, anyone interested was able to access the images on the Internet from anywhere in the world. The viewing angle of the cameras was also extended. A camera frame specially developed at GEOMAR provided a 180° view. Head-mounted displays ensured that team members could look in any direction at any time, independent of other researchers.
After the trip, the scientific team began evaluating and processing the data, creating a 3D model with an even higher resolution. This 3D model will also make virtual walks over the hydrothermal field with its black smokers possible in the future.
Further information:
A Youtube video of the "Virtual vents" expedition
More information iformation on Black Smokers
