In the study area the African and South American plates diverge about four centimeters per year. Therefore, magma lies very close to the ocean floor and heats sea water that circulates through cracks in the sea floor. Normally its temperature is much lower than the record 407°C.
Up to now, temperatures of up to 402°C were only known from pacific hydrothermal vents. “This increase of the record by 5 °C is significant as 407 °C at 3,000 meter depth marks the critical temperature, where water is no longer a fluid but reaches the state of “critical vapor,“ says cruise leader Andrea Koschinsky from the International University of Bremen. In this state water has different chemical and physical properties, meaning that it leaches materials differently from the surrounding bedrock. The resulting super hot solutions spewing from the black smoker are markedly different because of this.
According to geologist Prof. Colin Devey of the Kiel-based Leibniz Institute of Marine Sciences the unusually high water temperature indicates a comparatively recent start of the volcanic activity, which is also corroborated by new lava outcrops observed in the same sea floor area.
The Meteor expedition M68/1 from April 27 to June 2, 2006, explores the correlation between volcanism, water circulation inside and above the sea floor and hydrothermal vent organism communities. In addition to the super-hot vent it also discovered other, to date uncharted hot deep-sea wells. This was facilitated by combining the abilities of the autonomous deep-sea vehicle „ABE“ specially developed by Woods Hole Oceanographic Institute for locating hot vents and the remotely operated vehicle „QUEST“ of Marum at the University of Bremen. While ABE located venst, QUEST took samples and charted the area. The expedition is part of the DFG (German Research Foundation) Priority Program 1144 „From Mantle to Ocean: Energy-, Material- and Life-cycles at Spreading Axes” and is co-financed by the U. S. National Oceanographic & Atmospheric Administration.
Participants in the Meteor Cruise 68/1 (27.4.-2.6.2006) come from the marum, the universities of Bremen, Hamburg, Kiel, Munster and Otago (New Zealand), the IUB, the Leibniz Institute of Marine Sciences, the Max-Planck-Institute for Marine Biology in Bremen, the National Oceanographic Institution in Great Britain and the Woods Hole Oceanographic Institution in the USA.
MARUM & RCOM