Dr. Till Harter
Principal Investigator
I’m a comparative physiologist with broad interests in mechanistic cardiovascular and cellular physiology. My main research focus has been to understand how red blood cells work to deliver oxygen to all other cell types and remove the waste product carbon dioxide. Disruptions of a continuous cellular oxygen supply underlie many health conditions in humans (such as strokes, heart attacks and COPD), may exclude most mammals from life at high altitudes (but a few mouse species are notable exceptions), and may limit the survival of fishes to man-made environmental change. My goal is to understand how phenotypic plasticity in red blood cell function helps vertebrates to maintain a continuous oxygen supply during environmental and metabolic stress, and how the red blood cells from some species have adapted to enable life in extreme environments (e.g. frigid Antarctic waters or high altitude hypoxia). I obtained my PhD from The University of British Columbia in Vancouver, with Colin Brauner, and worked as a postdoc at the Scripps Institution of Oceanography in San Diego with Martin Tresguerres, and McMaster University in Hamilton with Graham Scott. Since 2024, I’ve been working as a Research Group Leader at the GEOMAR Centre for Ocean Research in Kiel.
Dr. Isaac Rossetto
Postdoc
Isaac is an evolutionary physiologist broadly interested in complex trait evolution and sensory biology. He joined the Harter lab in the Summer of 2025, where he is characterizing the cellular mechanisms of oxygen and acid-base sensing in the red blood cells of Atlantic cod. Isaac obtained his PhD from the University of Adelaide, with Prof. Kate Sanders, on the Evolution of the Sea Snake Visual System. He also has experience as a fisheries observer at the Australian Fisheries Management Authority (AFMA). Isaac is also volunteering his time as a member of the Posdoc Plus Team at GEOMAR.
Femke Thoben
PhD Student
Femke is a comparative physiologist and started her PhD project in the Harter lab in the summer of 2025. She’s currently studying the phenotypic plasticity of red blood cell function in Atlantic cod affected by rapid climate change. Femke is an experienced mariner, having worked on cruises with the FS Meteor, Heincke and Alkor, from the tropics to the Arctic. Femke obtained her MSc. at the University of Kiel with Prof. Marian Hu on the role of digestive acid-base physiology in larval sea urchin. Femke is currently also volunteering her time as a member of the Doc Team at GEOMAR.
Antonia Kirner
MSc. Student
Antonia is currently a MSc. student in Biological Oceanography at GEOMAR. In the Harter lab, Antonia provides technical assistance with fish capture, animal husbandry, system maintenance and laboratory work. Being an avid diver, Antonia also volunteers her time in the recovery of ghost nets and the restoration of seagrass meadows in the Baltic Sea.
Julian Kuniss
MSc. Student
Julian is finishing his MSc. studies in Biological Oceanography at GEOMAR and conducting his thesis work in our group. Julian’s project investigates the effects of temperature on anion exchanger (Band3) activity in the red blood cells of Eastern Baltic Cod and whether these cells show phenotypic plasticty in response to environmental stressors.
Joshua Berg
MSc. Student
Joshua is currently completing his MSc. in Biological Oceanography at GEOMAR and is carrying out his thesis research in our group. His research examines how changes in temperature influence the activity of the anion exchanger protein (Band3) in the red blood cells of Western Baltic Cod, as well as the capacity of these cells to respond to environmental stress through phenotypic plasticity.