PhD defence by Magnus Heide Andreasen

Magnus Heide Andreasen, DTU Aqua, will defend his PhD thesis "Global change and invasive jellyfish: hypoxia, fish predation and ecosystem effects" on Friday, 10 January 2025 at 1 p.m. 

You can attend the defence online on Zoom via this link or in person at DTU, Anker Engelunds Vej, 2800 Kongens Lyngby, building 303A, auditorium 41.

Magnus Heide Andreasen's thesis focuses on the invasive jellyfish Mnemiopsis leidyi and oxygen depletion in the Baltic Sea. The jellyfish is tolerant to oxygen depletion and therefore thrives in the inner Danish waters, where it competes for food with native jellyfish and fish. Magnus Heide Andreasen’s experimental research shows, among other things, that M. leidyi can thrive even in near-anoxic conditions where fish don’t thrive. Fish may be effective predators of M. leidyi and experiments did reveal a predator – the three-spined stickleback – but low oxygen levels reduced its predation impact drastically. Consequently, the thesis highlights the urgent need to improve oxygen conditions in coastal areas as a critical step toward restoring robust and balanced ecosystems.

A copy of the thesis is available for reading at DTU Aqua. Please contact PhD Coordinator Susan Zumbach Johannesen, szjo@aqua.dtu.dk

Examiners

• Professor Marja Koski, DTU Aqua (chair)
• Associate Professor Fabien Lombard, Laboratoire d’Océanographie de Villefranche, France
• PhD Lene Friis Møller, Verdensmålshuset Genin, Denmark

Chair at defence

• Associate Professor Mikael van Deurs, DTU Aqua

Supervisors

• Principal supervisor: Professor Torkel Gissel Nielsen, DTU Aqua
• Co-supervisor: Senior Researcher Mollie E. Brooks, DTU Aqua
• Co-supervisor: Senior Researcher Jane W. Behrens, DTU Aqua