On the shoulders of giants – by Matthew Watkins (www.watkinsmedia.com)
When I was at school I loved science but I hated having to learn about the history of science. Why did we need to spend weeks in chemistry class learning all the stages in the development of a model of the inner structure of atoms? Couldn’t they just have taught us the most up-to-date model? Today I have a much greater appreciation for the history of science and why it is taught. I have also discovered in my own research that ‘old’ science is not bad science but may simply have been limited by the technology available at the time. The ideas and insights of previous scientists are invaluable and have radically influenced my research.
The way that the historical development of science was presented at my school was quite misleading as it suggested that there had been a linear progression. The only way was forward and as soon as a new technique or theory was established there was no looking back. The scientific ideas also often appeared to magically coincide with the technological advances that were required to test a particular theory. There is of course no magic to this process; in many disciplines there is rather a push and pull between ideas and technologies. The ideas often come first, and some of them are so compelling that they push for technological advancements. Perhaps the most impressive example of this is the Large Hadron Collider constructed by the European Organization for Nuclear Research (CERN) in response to the theories on subatomic particles, antimatter, and the origin of the universe. In other instances ideas are deemed impractical due to technological barriers and are left behind. Some are then forgotten, while others are brought back to life as soon as technology catches up. A good example is electric vehicles: these were among the first cars in the world and were far more popular in the 1800s than their fossil fuel counterparts. Due to their limitations (mostly with respect to range, recharging, and cost) they were later replaced by gasoline-powered vehicles. Now that technology has improved the quality of batteries and reduced their cost due to their widespread use and adaptation for consumer electronics, electric vehicles are once again in fashion.
I recently had a similar experience in my own research. I was analysing hyperspectral data for a sediment core from a lake in Ethiopia and found a mineral called analcime to be present throughout the core. Changes in its abundance along the core seemed to coincide with climatic transitions. As it turns out, there have been a number of previous investigations into the behaviour of analcime in response to environmental changes. Most of these date back to between the late 1960s and the early 1980s, after which the popularity of this subject decreased rapidly and analcime never made it onto the list of popular climate proxies. This was probably due to the lack of supporting technology: yes, analcime could be quantified through x-ray diffraction but this was an expensive, labour-intensive, and destructive method that was just not practical for the high resolution analysis of long sediment cores. Micro x-ray fluorescence (XRF) scans, which have become popular for investigating sediment cores, provide data at high resolution but can only measure the relative abundance of elements. Since analcime contains only sodium, aluminium, silicon, oxygen, and hydrogen, all of which can be found in a variety of common minerals, there is no way that the abundance of analcime can be deduced from XRF scans.
In that regard hyperspectral imaging is a game changer. The cameras can scan a core at a resolution in the micrometer range and the presence of analcime can be tested in every pixel of the image because the suite of absorption features it imprints on the reflectance spectra is unique. The depth of these absorption features even allows quantification of the mineral. The results that I have obtained to date are promising: both the Younger Dryas and the Last Glacial Maximum, two periods of relatively cold and dry conditions, are marked by higher analcime contents in the hyperspectral data. Thanks to the high resolution, the data even provided evidence of an underlying process in which the pH of a terminal lake is buffered at the beginning of dry periods.
I am optimistic that hyperspectral imaging will find its way into the accepted techniques for analyzing sediment cores. Not only is it the first technique to allow high resolution analysis of mineral content, but it is also quick, cheap, and non-destructive. I am amazed at how technology has once again revived an old scientific idea. Of course it remains to be seen if analcime can prove itself among the other established climate proxies, but this experience nevertheless makes me wonder how many other great ideas are just waiting for the right technology to be able to change the world!
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Jan Schuurman