Dr Christian Bock (Laboratory Manager)
Dr Jan Tebben
The heart, the foot, the muscle of the common mussel – you can see everything very well on the computer image. It is one of many organisms that is examined using the nuclear magnetic resonance imaging technique of the NMR laboratory at the Alfred Wegener Institute. NMR stands for nuclear magnetic resonance – better known by the abbreviation MRT that is used in hospitals. "In our lab, we study how animals react to climate change, such as to changes in temperature or oxygen content in the water. We can use the tomograph to simulate this and observe the metabolic response of the organisms," says laboratory manager Dr Christian Bock. Together with his colleagues, he looks deep inside the animals – they even look into the brain of fish. And they use a high-performance device to do this.
Thanks to a field strength of 9.4 Tesla, the tomograph (which was newly installed at the beginning of 2016 ) provides high-resolution images – even of the tiniest organisms. "In the past, we studied fish, mussels, snails and worms using the tomograph that had to be at least several centimetres in size. Today, we can easily achieve a resolution of 100 micrometres for layered images. This should now allow us to examine the organisms in their juvenile stages and even analyse zooplankton like krill or copepods," says Christian Bock.
The common mussel is an example of this. Although we were able to study it in the past, what we were not able to do was to detect copepods in the intestinal tract of the mussel. The scientists of the Alfred Wegener Institute now have the perfect research conditions to perform such studies.
The strong magnetic field is generated by a superconducting coil, which, on the inside of the tomograph, is cooled down to a temperature of minus 269 degrees. This requires liquid helium. The current strength required to generate the magnetic field in the coil can be 190 amps. The tomograph weighs in at 10.5 tons. It is so heavy because of the iron, which is needed to shield the magnetic field.
"With our system, we will remain competitive for the coming 10 to 15 years," says Christian Bock. What's also still unique is the current canal that the AWI scientists work with in the NMR laboratory. This canal, which is unique in the world, allows the researchers to directly study the metabolism of swimming fish. The canal's current speed can be changed to do this.
The researchers are also able to change the temperature and the concentration of carbon dioxide in the water for their experiments. They can observe, for example, how the performance of fish potentially changes in warmer and more acidic water. This is interesting for the researchers, because, in the course of climate change, the oceans also change in the same manner.
"We have built a high level of expertise in our NMR lab and are carrying out major basic research. Our advantage is that we can use the tomograph exclusively for marine research. In most other laboratories, environmental research is performed on the side, so to speak , because the main purpose of the devices lies in clinical research," according to Christian Bock.
However, in addition to the basic research, it also has the occasional important practical application. The tomograph can be used for aquaculture research at the AWI, to determine, for example, the fat content of fish during breeding.