Associate Professor Mark Bayley died suddenly Saturday February 7, 2026, in his home. He was out in his garden doing some practical work. 

Mark Bayley studied biology in Edinburgh but had met his future wife Lene during a summer-visit to Denmark, where he worked in an aquaculture-farm. To be closer to Lene, Mark moved to Aarhus in the 1980ies where he completed both MSc and PhD with Erik Baatrup as supervisor combining ecotoxicology and behavior in invertebrates. Mark then embarked on series of studies on cold tolerance in fossorial insect together with Hans Ramløv and Martin Holmstrup and their findings were published in both PNAS and Science. Mark became part of the section for Zoophysiology in 2003.

Mark was amongst the earliest faculty in Aarhus to be engaged in the formation of a biology program in Cantho (the main city of the Mekong delta in Vietnam) where he established courses in ecophysiology and later in comparative physiology. Several students came to Aarhus to work with Mark on various projects, and he later obtained more than a decade of generous support from DANIDA to build laboratories and aquaculture facilities in Cantho. More than a dozen PhD students, both from Denmark and Vietnam completed their degrees under Marks supervision and more than 30 published papers on the physiology of air-breathing fish now inform the large aquaculture industry in that region. 

Mark also arranged three international PhD courses in fish physiology where students from Europe, Asia, Brazil and North America convened in Cantho for two weeks with an equally impressive group of older researchers that gave lectures and supervised research projects. 

Mark took on a large number of administrative duties and was chair the PhD school, of our Department and he had assumed the role as section head for Zoophysiology by the start of 2025. 

For several years, he served as leader of the PhD program in biology at the Graduate School of Natural Sciences, where he also held a seat in the PhD committee - assignments that he approached with seriousness and personal commitment combined with a conscientious balance between pragmatism and rules, and always with the best interests of PhD students and research in mind.

He taught on several bachelor and master’s courses and his course of ecotoxicology was widely attended, also by many international students. He supervised many students at all levels and maintained close relationships with them in many years after. Several are now in academic positions both in Denmark and elsewhere.

In addition to his academic merits, Mark also left a pronounced personal mark on his surroundings. He was very open-hearted in his meetings with other people, and both students and colleagues benefited from this. He met everyone with an accommodating mind and a characteristically disarming laugh that was loved by all that encountered him. He was deeply passionate about high-quality education and research and always strove to make a difference for the students. He was conscientious and generous in his work, but also a great lover of life, always in good spirits. His warm, heartfelt laughter often echoed wherever he went, and he was always available for a talk about life and other big issues.

Mark was only 62 years old and leaves his wife, two sons and grandchildren. He was a devoted husband and father and immensely proud of his sons, Jeppe and Svend and of his grandchildren. Mark will be dearly missed, not only by his family, but by students, colleagues and collaborators. 

May Mark’s memory be honoured.