Anyone who wants to make accurate predictions about the future of our climate has to first know how it developed in the past. At the Alfred Wegener Institute’s Proxy-Lab, researchers from the Marine Biogeosciences Section are delving hundreds of thousands to millions of years into the past – with the help of fossilised organisms and cutting-edge mass spectrometers.
“Technically what we’re looking for are proxy data for climate parameters from the past. Information on what the water temperature, salinity and pH balance of the oceans were like back then is all preserved in the fossil remains of mussels, corals and the calcium carbonate shells of minute foraminifera,” explains the lab’s director, Dr Albert Benthien.
But these witnesses of the past don’t always share their secrets so easily: “We check the organisms for certain isotope signals, or examine the ratios of specific chemical elements. That information allows us to draw conclusions about the water temperature or other relevant climate parameters,” adds Benthien.
This type of research involves taking complex measurements with the Proxy-Lab’s three ICP mass spectrometers. Selected samples are also probed with a femtosecond laser, which is used to separate minuscule amounts from the original sample; these are then directly fed into the mass spectrometers for analysis. The advantage of this method: it offers the researchers maximum results based on only minimal materials, and the wealth of point measurements produced provide the measurement data with a high degree of spatial resolution.
The disadvantage: even the smallest grain of dust or any other particle can distort the measurements. As such, the researchers have to primarily work under cleanroom conditions, especially in the part of the Proxy-Lab used for sample preparation, which means e.g. the air pressure is kept higher than normal, helping to ensure that dust particles don’t enter the preparation area to begin with.
To see how the measurements at the Proxy-Lab work in detail, and which research questions they’re helping to answer, please consult the following info-graphic.