PhD students

PhD students and projects at DTU Aqua within the research area Oceanography.

Magnus Heide Andreasen

Title of the PhD project
Global change and gelatinous zooplankton: Mechanisms and responses of jellyfish population dynamics to global change induced stressors

Supervisors
Torkel Gissel Nielsen and Mollie E. Brooks (DTU Aqua)

Background of the project
Gelatinous zooplankton organisms are a diverse group of soft bodied, transparent organisms that comprise members from diverse phyla in the animal tree of life. They commonly attract large public attention partly due to their bloom and bust population dynamics, partly due to their interference with human activities especially in coastal waters. It has been suggested that their abundances are on a rise due to global change induced stressors. However, the data and experimental basis to support this hypothesis remains inconclusive.

About the project
The aim of this PhD project is to address the hypothesis that gelatinous zooplankton biomass is increasing due to global change induced stressors from a time series as well as experimental perspective. The project will combine statistical modelling with laboratory-controlled experiments.

Perspectives
The results are expected to further our understanding about gelatinous zooplankton’s long-term abundance fluctuations, their underlying population dynamics and the response of certain sub-populations to global change induced stressors.

Athanasios Kandylas

Title of the PhD project
Carbon sequestration and oxygen minimum zones

Supervisors
Andre Visser and Ken H. Andersen (DTU Aqua)

Background of the project
Oceans play a crucial role in regulating and stabilizing the Earth’s climate having stored nearly 40% of the anthropogenic CO₂ emissions since the industrial revolution. However, potential tipping points might lead to abrupt changes of critical physical and biological processes affecting important marine ecosystem services, such as carbon sequestration and food production. Even though the science around the physics of climate change is robust, our understanding about the response of the marine ecosystems to these changes is still incomplete.

About the project
The aim of this PhD is to develop a framework through advanced ecological modelling which will be able to give an insight into the ecological state of the majority of the marine ecosystems around the world. We expect that at the end of this process, we will have gained a better understanding of two important and interrelated phenomena: Carbon Sequestration and Oxygen Minimum Zones (OMZ) in the ocean. To accomplish this, the Nutrient – Unicellular – Multicellular (NUM) framework and the SISSOMA, a specialized aggregation model, developed in the Centre for Ocean Life will be applied.

Perspectives
Overall, in a fast-changing world we need to be able to make accurate predictions about the function and structure of marine ecosystems on a global scale. The tools developed in this project work on this direction and they will hopefully help us to take critical management decisions on time.

Themistoklis Konstantinopoulos

Title of the PhD project
Ecosystem effects of maritime activities

Supervisor
Marja Koski and Sinja Rist (DTU Aqua) and Ida-Maja Hassellöv (Chalmers University)

Background of the project
The shipping industry is shifting to greener fuels, like ammonia (NH₃) and methanol (MeOH), following the instructions of the International Maritime Organization (IMO) to substantially reduce greenhouse gas (GHG) emissions. This shift imposes the risk of spilling these substances into the marine environment. The effects of NH₃ and MeOH on marine microbial life are not yet fully understood. Existing literature indicates potential adverse effects on marine food webs. However, plankton communities, especially in areas like the Baltic and North Seas, are not sufficiently studied. Given the significance of zooplankton in energy transfer within marine food webs, it is crucial to study their response to NH₃ and MeOH under different environmental conditions.

About the project
During my PhD, I will collaborate with experts from Danish and Swedish universities. We will conduct sampling surveys to assess current conditions in the Baltic and North Seas, focusing on environmental parameters and zooplankton community composition. Subsequently, I will perform ecotoxicology experiments by introducing ammonia and methanol under various environmental gradients to simulate changing conditions in these areas. Finally, I will implement the results to create computational numerical models to be used in environmental impact and risk assessments.

Perspectives
Copepods play a crucial role in energy transfer and greatly contribute to ecosystem services. My project aims to understand and explain the toxicity mechanisms of ammonia and methanol on copepods under different environmental conditions. The knowledge produced by this PhD will help us understand the ecosystem effects of the energy transition in the shipping industry. Additionally, I will develop numerical tools that can be used in future ecotoxicology studies.

PhD at DTU Aqua

The PhD programme at DTU Aqua educates future researchers within the institute's research areas for a career in academia or business.

Learn more about the PhD programme at DTU Aqua

Previous PhD student within the research area Oceanography

Caroline Gjelstrup
Changing oceanographic conditions in East Greenland (link awaits publication of thesis)

Federica Miano
Fluid dynamics, ecology, and evolution of marine flagellates. Motility, foraging mechanisms, and defense strategies (link awaits publication of thesis)

Kristian Maar
Ecology and fluid dynamics of aquatic suspension feeders

Delove Abraham Asiedu
Effect and bioaccumulation of mercury in Arctic marine plankton under climate change

Gunaalan Kuddithamby
Microplastics in marine waters and their potential risk to marine plankton

Sei Suzuki-Tellier
Feeding mechanisms in phagotrophic nanoflagellates. Predation in the Low Reynolds Number World

Anders Dalhoff Bruhn
Terrestrial and coloured dissolved organic matter in Arctic waters: Towards in-situ sensor based monitoring of Arctic-Atlantic organic carbon exchange at major Arctic gateways

Josephine Grønning
Defence in diatoms: mechanisms and trade-offs

Rocío Rodríguez Torres
Ingestion and effects of microplastics on marine planktonic food webs

Mads Rode
Physics of microbial feeding. Studies of feeding flows near surfaces, ciliate filtration, and non-intrusive tethering of microswimmers

Frederik Ryderheim
Opening the black box on predator-induced phytoplankton defenses: mechanisms, traits, and trade-offs

Jérôme Pinti
Vertical Migration: Structure and function of pelagic ecosystems

Agnethe Nøhr Hansen
Plankton Trait Ecology in a Changing Marine Environment

Marina Pancic Mohr
Defense mechanisms in phytoplankton: traits and trade-offs