Oceanography
Scientific results stemming from the studies introduced in the following have been published in various papers. Please, click here to find a list of relevant publications.
Our recent research projects are listed here.
- Water Mass Analysis
- Water Mass Ages
- Subduction Rates
- Hydrothermal Vents
- Dating
3He/4He - Isotopes Ratios
There is a steady flux of helium from the inner earth through the ocean and atmosphere to space. The isotope ratio of the captured helium is very different from that of the atmospheric helium. If helium leaves the earth interior through mid ocean ridges it is dragged by the ocean current. This makes the old, so called primordial helium a perfect tracer for the deep ocean circulation. Or the other way around: a signal of primordial helium in water close to the ocean ridges indicates hydrothermal vents. Some research projects dealing with the analysis of helium isotopes are the followin:
- how to separate the sources for helium in various water masses?
- how does helium from the deep Pacific waters pass through Drake Passage and enter the Atlantic?
- where in the Atlantic can we find helium originating from hydrothermal vents?
- how does helium from the deep ocean enter the atmosphere through gas transfer?
4He/20Ne
There are no sources for the isotope 20Ne in the inner ocean. Therefore all neon originates from the atmosphere and is a perfect indicator for the atmospheric gases in the ocean. With this one can identify non-atmospheric 4He. The source for this 4He is the radiogenic production from uranium an thorium decay in the sediment. At the coasts of Antarctica and Greenland icebergs are melted from below by contact with ocean water. Atmospheric gases within the ice are then dissolved in the water and can be detected as excess gas. This allows to trace melted continental ice in the oceans.
20Ne/22Ne
Variations of the 20Ne/22Ne - isotope ratio result from different gas input parameter of the sample and give information about the quality of the analysis.
3He/T-Dating
Surface water of the ocean gained large quantities of tritium from the nuclear weapon tests in the early 1960ies. In the so called convection regions tritium has been carried to deeper layers of the ocean. Therefore, it is a tracer for water which had contact to the atmosphere during the last decades.
Tritium decays to 3He with a half-life-time of 12.32 year. The combination of tritium and its decay product allows to calculate an age, synonymous for the time difference between last contact to the atmosphere and sampling.