School of fish. Anna Varona, CC BY 4.0 <>, via Wikimedia Commons

PhD defence about vertical migration of marine organisms

Tuesday 24 Nov 20


Andre Visser
DTU Aqua
+45 35 88 34 25

On 4 December 2020, PhD Student Jérôme Pinti will defend his PhD thesis. The defence can be watched online.

Zooplankton, fish and other marine organisms move between the surface of the oceans and deeper waters every day. Zooplankton typically reside at depths during daytime to avoid predation from visual organisms. At night, zooplankton migrate to the surface to feed on small phytoplankton, and fish and other organisms feeding on zooplankton follow their prey to the surface. This movement is called diel vertical migration and is believed to be the largest natural daily movement of biomass of the planet, only potentially exceeded by human commuters.

During his PhD study at DTU Aqua, Jérôme Pinti has developed a method that can improve our understanding of the optimal vertical migration patterns. The method relies on game theory, where organisms are seen as players trying to optimize their fitness—a measure of how well they are doing—considering the behaviour of all other organisms.

Jérôme Pinti has used the method to model, among others, a whole pelagic community—from mesozooplankton to mesopelagic fish and large pelagic fish—and has predicted their global vertical distribution. 

Further, Jérôme Pinti has examined the effect of diel vertical migrations on the global carbon cycle. By feeding close to the surface during day and respiring and excreting fecal pellets at depth during night, organisms actively transport carbon to the depths, thus participating in reducing atmospheric CO2. Jérôme Pinti found that on a global scale, forage fish and especially mesopelagic fish are more important contributors to carbon sequestration than previously assumed.

About the defence

Jérôme Pinti, DTU Aqua, will defend his PhD thesis "Vertical Migration: Structure and function of pelagic ecosystems” on Friday 4 December 2020 at 13:00 (CEST) via Zoom. Find link to Zoom below.


  • Principal supervisor: Professor André W. Visser, DTU Aqua
  • Co-supervisor: Professor Thomas Kiørboe, DTU Aqua
  • Co-supervisor: Senior Researcher Patrizio Mariani, DTU Aqua


  • Senior Researcher Asbjørn Christensen, DTU Aqua
  • Dr. Olivier Maury, French National Research Institute for Sustainable Development, France
  • Professor Josefin Titelman, University of Oslo, Norway

Chairperson at defence

  • Senior Researcher Karen Edelvang, DTU Aqua
Learn more

A popular science summary of the thesis can be downloaded here

A copy of the thesis is available by e-mail on request. Please contact Karin Stubgaard,

Link to Zoom and guidelines for attending the defence

It is possible to attend Jérôme Pinti’s defence on Zoom using this link:

Please, enter the meeting 10 minutes prior to the defence proceedings are scheduled to start.

All participants are muted per default, but we ask you to double check that both camera and microphone are turned off at all times.

There will be instructions regarding the proceedings in the beginning of the defence. After the members of the assessment committee have had time to raise their questions to the candidate, questions from the audience will be addressed if the remaining time allows for it.

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