A leading voice in interdisciplinary marine science has fallen silent

Hans-Harald Hinrichsen was born on 13 March 1952 in Flensburg. After completing an apprenticeship and working as an insurance broker, he began studying physical oceanography at Kiel University in 1977. He received his Diploma in 1985 under the supervision of Prof. Wolfgang Krauß.

Following his studies, Hans-Harald began his scientific career at the Institute of Marine Sciences in Kiel (IfM), the later GEOMAR. A formative early phase was his work within the Collaborative Research Centre (Sonderforschungsbereich) “Environmental Change: The Northern North Atlantic”, complemented by a research stay at the Alfred Wegener Institute in Bremerhaven. Interdisciplinary collaboration and numerous research cruises during this period laid the foundation for his scientific approach of consistently linking physical processes with biological and ecological questions.

Since 1995, Hans-Harald Hinrichsen worked as a physical oceanographer at the IfM, initially in the Fisheries Biology department and later in Marine Evolutionary Ecology. His research focused first on Mediterranean water systems and subsequently on the Baltic Sea and North Sea. He made substantial contributions to hydrographic time series and to the understanding of the specific oceanographic features and dynamics of the Baltic Sea.

Hans-Harald Hinrichsen was internationally recognised as an expert in marine ecology and fisheries biology. He served as co-chair of the ICES study group on closed spawning areas of eastern Baltic cod and was involved in numerous national and international research projects and collaborations. These included, among others, the EU projects CORE and STORE and the German GLOBEC project, which addressed fish stock recruitment and its oceanographic drivers. Further studies examined interactions between the physical environment, marine ecosystems and fisheries, as well as the impacts of climate change and climate variability on ecosystems and biodiversity.

Over the course of his scientific career, Hans-Harald Hinrichsen published more than 220 scientific contributions. His work focused on modelling oceanographic processes and biophysical linkages, particularly drift and dispersal models of early life stages of marine organisms. These studies provided key insights into spawning and nursery areas of commercially important species and helped improve understanding of the spread of non-indigenous species, forming an important basis for spatial conservation and marine protection concepts. In later years, he increasingly focused on modelling and forecasting changes in oxygen levels in the Baltic Sea and on the impacts of climate change on the regional food web. He was awarded the GEOMAR Publication Prize in recognition of his outstanding publication record.

Even after his official retirement in 2017, Hans-Harald Hinrichsen remained closely connected to GEOMAR and to marine science. Until shortly before his death, he continued to contribute to data analyses and modelling, to mentor young scientists and to publish. His last scientific paper was published in December 2025.

What made Hans-Harald Hinrichsen’s scientific work particularly distinctive was his openness to integrating biological questions into a physical oceanographic framework and his commitment to applying scientific knowledge in a societally relevant context. With his interdisciplinary perspective, he pioneered work that laid the physico-chemical foundations for understanding the dispersal and development of marine species across the diverse habitats of the Baltic Sea, leaving a lasting impact on the field.

At the same time, Hans-Harald Hinrichsen was a tireless mentor to students and colleagues at GEOMAR and beyond. His ability to connect scientific disciplines, develop innovative solutions and his enduring curiosity and perseverance made him an inspiring colleague and highly valued discussion partner. He will also be remembered as a humorous and dedicated colleague and as a social anchor for many research teams – and as an enthusiastic cyclist whose long rides to work impressed us all.

We are deeply saddened by the loss of a sharp and curious scientific mind, a passionate researcher, a respected colleague and a dear friend. H₃ – we will truly miss you.

Our thoughts are with his wife, his family and his friends.

Text by Catriona Clemmesen, Jan Dierking, Conny Jaspers, Fritz Köster, Andreas Lehmann, Felix Mittermayer and Thorsten Reusch