The GFZ and the Ocean

The Science Year 2016*17 „Seas and Oceans“, declared by the Federal Ministry of Education and Research (BMBF) is dedicated to marine research. The GFZ is the centre for solid earth sciences. There are, however, several points of contact and cooperations with the sea sciences. System Earth is complex and consists of interacting subsystems and cycles. Therewith the research of several GFZ scientists also contributes to a better understanding of seas and oceans. Within our overview we present some of them.

 

Dr. Saskia Esselborn: Radar satellites provide precise measurements of the global sea level. Based on these data Saskia Esselborn investigates how sea level changes in time – as a global mean and for single regions in the North Atlantic or at the Northern Sea. She tries to bring her results together with potential forcing mechanisms: What is the role of ocean warming and the thawing of polar ice caps? And how do these changes interact with the atmospheric and oceanic circulations?

 

Dr. Mathias Bochow: The remote sensing specialist Mathias Bochow deals with the problem of plastic waste in the oceans. He aims at tracking sources, sinks, and routes of transport of the waste to reduce its input to the oceans. Since especially micro plastic is much too small to be “seen” by satellites he, together with several colleagues, tries to develop an indirect approach for the spatial mapping of micro plastic in samples of water by using high frequent imaging infrared spectroscopy.

 

PD Dr. Judith Schicks: Gas hydrates are ice-like solid structures that consist of water and gas molecules – natural hydrates mainly consist of methane. Natural gas hydrates for example occur in marine sediments of continental slopes. Some estimates suggest that they bind twice as much carbon as all known mineral oil and petroleum gas resources. Judith Schicks is Head of the working group “Gas Hydrates” at the GFZ that for example deals with the question of how to use methane gas resources from natural hydrates in a sustainable way. Thereby it is also investigated if gas hydrates are qualified storage mediums for CO2 at the sea floor.

 

Dr. Jörn Lauterjung: After the devastating tsunami in the Indian Ocean in 2004 the GFZ was mandated with the development of a tsunami early warning system – Jörn Lauterjung was project manager. Compared to existing systems within the Pacific the geological situation of Indonesia with its short time spans between earthquake event and the arrival of a tsunami wave at a shore, requires a novel system approach. In November 2008 the German-Indonesian Tsunami Early Warning System GITEWS started operations. The interplay between land-based seismometers and GPS sensor systems, seismological analysis systems, tide gauge stations, and a decision supporting system including a modelling component now allows for an early warning below five minutes.

 

Dr. Inga Bergmann-Wolf: The Earth’s gravity field, illustrated by the “Potsdam Gravity Potato”, changes within time. These changes are mainly caused by redistribution of water masses that are detected by the GRACE satellite mission. The geodesist Inga Bergmann-Wolf deals with the oceanographic applicability of the observed data. She for example determines temporal variations in the total volume of the oceans. By analyzing the satellite data she can also recognize regional changes in water mass transport that are for example stirred by winds.

 

Dr. Tobias Weber: Plate tectonics that cause shifting of continents and volcanic activity lead to the opening and closing of ocean straits and the redirection of ocean currents. The mathematician Tobias Weber investigates the impact of plate tectonics on the oceans. He models dynamics of oceans and the atmosphere in Earth’s history. Thereby he was able to show that the closing of the strait between the Atlantic and Pacific Oceans in Central America about 5 million years ago strengthened the Gulf Stream and caused higher temperatures in the North Atlantic as well as in Europe.

 

Dr. Foteini Vervelidou: As new magma comes out of the Earth's mantle at the mid-ocean ridges, it cools down and gets magnetized by the ambient magnetic field. Through this mechanism, oceanic crust offers a record of the history of the geomagnetic field, including its polarity reversals. These polarity reversals are being recorded on the oceanic crust as symmetric stripes of alternating polarity. This pattern was first observed in the 1950's and provided strong evidence in favor of the theory of plate tectonics. Foteini Vervelidou uses magnetic field data provided by the CHAMP and Swarm satellite missions to ameliorate the global view of this record.

27.07.2016: Ariane Kujau

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