For the last five years, Professor of Microbiology of Acidic Volcanic Ecosystems Huub Op den Camp has been researching three volcanic regions in Italy in an effort to find new bacteria and identify the microbial inhabitants. The new insights may be useful in addressing environmental and climate issues. “Once we’d taken field measurements on the island of Pantelleria and collected samples from the volcanic soil, we made an immediate start of the enrichment cultures in our hotel room. The entire room was filled with bottles and jars. The suitcase that accompanied us on the flight back to the Netherlands was full of tiny bottles.” Huub Op den Camp has been researching volcano bacteria for around fifteen years. “The microbiology department is interested in the carbon, nitrogen and sulphur cycles that are the driving forces in natural and man-made ecosystems.” For example, Radboud researchers not only look at how a cycle works on the plains of Russia, but also at how cycles work in Canadian lakes, in wastewater treatment systems, at the bottom of the deep ocean and in volcanic areas in Italy. And this obviously involves studying the role of microorganisms in particular, by looking at who converts which substances, and when and where this occurs. Volcano inhabitants In 2007, Op den Camp’s colleague Arjan Pol discovered special methane-eating bacteria in the Solfatara mud pool near Naples; news of this finding was even published in Nature. The living conditions in this volcanic pool may be defined as extreme with temperatures of 50 to 100 degrees and acidic conditions with pH values between 1 and 3. What’s more, Pol also accidentally discovered that these bacteria only grow in the presence of rare earth elelements. Since then, Op den Camp has been researching this and other ‘extremophiles’, which use mechanisms from which researchers can learn a lot about life under hostile conditions. Over the past five years, his visits to various volcanic areas in Italy, in which he was accompanied by three PhD candidates and two postdoctoral researchers, were funded by an ERC Advanced Grant. His goal was to compile an overview of the sources’ microbial inhabitants and their metabolism, ideally including a number of newly discovered ones. Picture: The microbiologists start the enrichment cultures from the volcanic soil of Pantelleria in their hotel room. “I look back on that period with a great sense of satisfaction. We’ve obtained an overall view of organisms that get their energy from hydrogen gas, sulphur compounds, carbon monoxide and methane. These last three are important greenhouse gases. We’ve also discovered a number of interesting new bacteria.” “But one of our most important findings is that rare earth elements, like cerium and lanthanum, really have been given their own role in life. After we discovered that the bacteria from the Solfatara mud pool proved to be dependent on these elements, we were truly able to take our knowledge to the next level. This had never been reported before.” Useful for the climate and the environment According to Op den Camp, you never know what this type of research will reveal. “One of our department’s greatest success stories would definitely have to be the discovery of the ammonium-eating anammox bacteria, which are now being used in hundreds of reactors that are scattered around the world.” The bacteria remove ammonium-nitrogen from wastewater turning it into harmless nitrogen gas. Fundamental knowledge about the role of different microorganisms in natural biogeochemical cycles is crucial. “For example, if we know exactly how the nitrogen cycle works and who the main players are, we’ll be able to better predict the effect of soil fertilisation, which involves pumping ammonia into an ecosystem. And how do bacteria such as methane-eating bacteria ensure a natural reduction of greenhouse gas emissions from volcanoes?” In the future, this knowledge could even be useful to reduce global warming. Image: Norbert Nagel / Wikimedia Commons