In Memoriam Hans Matthijs (1951 - 2016)
A passionate scientist, inspiring lecturer and beloved colleague has unexpectedly left our midst. Hans Matthijs was a biochemist who was fascinated by cyanobacteria and did ground breaking work on them for almost 40 years. After many years of primarily fundamental research, Hans wanted to give back to society and therefore recently began striking new paths.
Hans studied Chemistry at the UvA, and completed his PhD on the energy metabolism of the cyanobacterium Plectonema boryanum at VU Amsterdam in 1983. He then worked in various places around the world, including Brookhaven National Laboratory near New York, Université de Marseille/Aix II and Université de la Méditerrannée in southern France, as well as Washington University in St. Louis (USA). In 1991, he was hired as Assistant Professor at the UvA. In 2001, Hans was promoted to Associate Professor, and joined Jef Huisman and Petra Visser to form the core of the new research group in Aquatic Microbiology of the Institute for Biodiversity and Ecosystem Dynamics. During that period, he played a key role in obtaining fundamental new insights into the cyclic electron transport around Photosystem I and into the photosynthetic response of cyanobacteria to nitrogen and iron deficiency, among others.
In recent years, Hans' commitment to society led him to investigate possibilities for improved energy efficiency in algal cultivation and greenhouses. He hypothesised that if algae were exposed to the right wavelengths of light at the right times, much less light energy would be required to achieve the same photosynthetic production. Together with a PhD student and postdoc, he developed colourful chemostats with advanced LED lighting to substantiate his hypothesis.
Hans also recently studied effects of rising CO2 concentrations on cyanobacteria. Giovanni Sandrini defended his PhD thesis on this topic in early April. Though already gravely ill, Hans did not want to miss the PhD defence of his student, and brought his own special chair to attend the ceremony. It would be Hans' last appearance at the UvA. As the co-supervisor, he prepared the laudation. Hans said he had written a slightly longer speech than usual. The beadle understood his intentions and didn’t keep a strict watch. It ultimately became a unique and moving 20-minute laudation, which we will never forget.
Fighting blue-green algae
Another of Hans' recent ideas involved fighting toxic cyanobacteria (blue-green algae) with hydrogen peroxide. As a biochemist, Hans knew that cyanobacteria were much more sensitive to hydrogen peroxide than algae, because eukaryotic algae produce hydrogen peroxide in the Mehler reaction, while cyanobacteria do not, making them much more vulnerable to it. The major advantage of this control method is that it does not leave behind any chemical residue because the hydrogen peroxide breaks down into oxygen and water after it has served its purpose. Under Hans' inspiring leadership and in collaboration with Arcadis, various lakes were successfully treated with this method. In most cases the lakes were open again for recreational use within a few days.
Last year, Hans brought in new research projects to continue expanding on this method. Unfortunately, he will no longer see them come to fruition. Hans passed away on 17 April 2016, after a brief struggle with pancreatic cancer, but his research lines will be continued for many years to come.