Andrea Koschinsky, Professor of Geosciences at Jacobs University, led the successful research cruise.
(Source: Marie Heidenreich, PTJ)
March 03, 2017
Smoking chimneys at the bottom of the ocean, delicate columnar formations, goose barnacles in the shimmering water – these are the alien sights encountered on the sea floor by marine researchers on an expedition with the research ship SONNE. The 39 scientists under the leadership of Professor Andrea Koschinsky of Jacobs University in Bremen explored hot springs on undersea volcanoes of the Kermadec Arc off New Zealand.
At the volcanoes of the region, a number of so-called hydrothermal vents are already known, some of which were studied in detail during the SO253 expedition. In the process, the MARUM-QUEST unmanned underwater robot (MARUM, University of Bremen) also sniffed out some previously unknown springs. It dove in the middle of an area in which hot liquid rich in carbon dioxide issues from the floor of the sea. The living environment 670 meters beneath the sea surface is teeming with life: It abounds with barnacles, including goose barnacles, and the researchers also discovered tube worms, fish, lobster, shrimp, anemones, and mussels up to 30 centimeters long. In the brightness of the headlights, fluffy-looking mats of bacteria stand out against the dark background. “Often the search for hydrothermal fields is like looking for a needle in a haystack. It is great that we also discovered new hydrothermal fields and hot springs during this cruise,” says a jubilant Andrea Koschinsky about the find.
The fluid chemist from Jacobs University in Bremen led the expedition of the research ship SONNE, from which she returned at the end of January. For five weeks, she was joined by geologists, physicists, chemists, and biologists from Germany, New Zealand, France, and the USA to study the influence upon the oceans of hot springs on undersea volcanoes at relatively shallow depths: “The goal of the expedition was to find out how the materials from the hot springs influence the composition and bioproductivity of the upper water layers,” explains Koschinsky. In addition to Jacobs University, five other German partners took part in the excursion. They include the MARUM - Center for Marine Environmental Science/ University of Bremen, the Max Planck Institute for Marine Microbiology Bremen, and also the Universities of Oldenburg, Hamburg, and Münster. The research trip was carried out in close cooperation with scientists of the University of Otago and GNS Science in New Zealand. The SO253 expedition was funded by the Federal Ministry of Education and Research (BMBF), as well as the related evaluation projects of the German partners.
In contrast to the mid-ocean ridges, on which hydrothermal springs are often located at depths of more then 2000 meters, many undersea volcanoes of the Kermadec Arc come to within 100 meters of the sea surface. Their hydrothermal plumes can thus reach even the upper layers of the ocean. The researchers’ findings indicate that there is no one-size-fits-all answer to the question of the influence of the hot springs: “Some of these hot, metal-rich solutions have such a high salt content and high density that they fill the volcanic craters like a lens of brine or spill over their edges;” reports the scientist, “in contrast, at other hydrothermal springs, we were able to track the spreading of iron, a vital trace element in the ocean, for great distances.”
The Kermadec volcanic arc off New Zealand is one of the most geologically active regions in the world: This is where the Pacific plate dives beneath the Australian continental plate and where numerous volcanoes have formed, which very often erupt and change their shape. At the same time, they are also the basis for the development of the hot springs and their living world at the bottom of the sea. For example, the expedition traveled to a very active volcano that last erupted in the year 2008. The scientists found that all that remained of the volcanic cone was a column of lava about 90 meters high. “From cracks in this column, a warm, shiny liquid was escaping in some spots, which we sampled and which already contained some hydrothermal life,” reports the expedition leader, Andrea Koschinsky.
These and other samples are now on their way to Germany by container ship. In the meantime, all the scientists from the trip have returned to their home institutes to await the arrival of the containers and the samples, which will arrive in mid-March, after being transported halfway around the world. In its 19 dives, the MARUM-QUEST underwater robot not only took unique video images of the sea floor but also lifted 150 kilograms of rock samples and about 100 samples of the hot solutions on board. Added to this are hundreds of other water samples, which were taken from various layers of water in the surrounding region using water samplers to track the spread of the hydrothermal materials. In the coming years, the researchers will study the water and rock samples, as well as the animals preserved in alcohol and the microorganisms, in order to reach their goal: to understand the influence of hot springs of volcanic arcs upon the materials and life in the ocean.
Expedition blog: http://geschichten.ptj.de/so253#72058
Interview with Andrea Koschinsky on the web site of the German Federal Ministry of Education and
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Prof. Dr. Andrea Koschinsky | Professor of Geoscience
a.koschinsky [at] jacobs-university.de | Tel: +49 421 200-3567
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