As winter envelops the canal city of Groningen, in the northern Netherlands, another successful year ends for ECHOES, a multi-disciplinary project based at the University of Groningen and sponsored by the European Research Council. ECHOES revolves around the determination of past levels of radiocarbon in the atmosphere.

Radiocarbon is an isotope that can reveal information about the history of the sun and of the Earth's magnetic field and it, of course, underlies the well-known dating method. We make our determinations using samples of tree-rings, as trees absorb radiocarbon from the air as they grow. Furthermore, through the discovery and excavation of buried forests, and the careful matching the growth-ring patterns, long archives of wood exist in which the growth year of every tree-ring is known. After applying a little chemistry and physics in the laboratory, we are able to determine the radiocarbon concentration of such tree-rings, and hence the radiocarbon concentration of the atmosphere at particular times in the past.

The team

I'm Mike Dee, no relation of the Beastie Boy, and I lead the ECHOES team. In truth, I have several far duller responsibilities and most of the real research is done by my team members, Andreas Neocleous,Margot Kuitems and Andrea Scifo. Andreas is a data scientist. He has had a year full of True Positives. It began with the publication in IEEE Access of his estimates of when the most significant anomalies in radiocarbon occurred during the last 10,000 years. At the same time, he developed an open source application called Chronoscope, which gives everyone the chance to inspect past radiocarbon levels. Chronoscope is now available online, just in time for Christmas, and an accompanying article has been accepted for publication in the journal Radiocarbon. In April 2019, Andreas returned to his native Cyprus, where he took up a permanent position at the University of Nicosia. He remains a key member of the ECHOES team, and continues to advise us on all things data-related.

Andreas' protege, his quasi-namesake, Andrea Scifo, is our resident atmospheric physicist and PhD student. Andrea has been investigating the tiny fluctuations in atmospheric radiocarbon due to the changing behaviour of the sun. Last month, he had his first-ever article published in Nature Scientific Reports. In this piece, he argued that massive solar storms, orders of magnitude bigger than any witnessed in recent centuries, always occurred when the sun was at the high point of its activity cycle. This sounds like a no-brainer, but it actually took a lot of work, and has helped characterise these mega-storms as extreme examples of the solar flares we regularly observe today. 

Finding the radiocarbon signal of past solar storms in known-age tree-rings also allows us to date historical objects - sometimes to the exact year. This is because some of the signals are distinct, and can act like fingerprints, so that all we need to do is find them in wooden artefacts and we know the years we are dealing with. Our expert in this nascent procedure is the effervescent Margot Kuitems. Her main focus is to solve historical mysteries by careful analysis of radiocarbon signals in wooden artefacts. In June, Margot and I attended a conference in Athens, Georgia, the home of REM, in which she explained our new approaches. She also revealed how we had cracked the case of the ancient site of Por-Bajin in Russia. This spectacular and enigmatic structure was long thought to either be a royal palace, or an ancient religious centre. However, its true purpose has never really been scientifically established. By analysing wooden beams at the foundation of the structure, Margot and her Russian collaborators were able to establish the exact year it was built and reveal the reason for its construction. The results of this study are presently in review for publication.

Education

In 2019, ECHOES has also been home to Master's students in the Energy and Environment programme, Tarun Rohra and Sybren Couwenberg; Physics Bachelor's student, Peter Sarkozi; and archaeology Master's student, Pinar Erdil. Our goal is also to include the outputs of their research dissertations in future ECHOES publications.