RTG 2530 Short PortraitsWelcome to the team, Nele Martens!

26 January 2026, by RTG 2530

Photo: Çağıl Gümüş

Nele Martens has joined the RTG 2530 team as a Postdoctoral Researcher. We're delighted to introduce her as part of our portrait series, in which we asked her three questions.

1. What is the main focus of your research, and what are the overarching topics, questions or objectives?

In my current project at RTG 2530, I am investigating how viruses that infect phytoplankton affect carbon fluxes in the Elbe estuary. These viruses destroy (plant) phytoplankton cells, preventing them from being eaten by zooplankton (animal plankton) and instead causing them to be remineralised by bacteria, releasing CO₂ in the process. In previous RTG projects, genetic methods were used to show that different virus populations can be found along the estuary (Gołębiowska et al., in prep.; PhD project in RTG 2530), but the effects on biogeochemical fluxes have not yet been directly investigated. Using data already collected (and future data) from the RTG, I would like to create an ecosystem model that can represent carbon fluxes in the Elbe estuary in connection with phytoplankton viruses. I am particularly interested in how environmental factors in the Elbe estuary affect viral infections of phytoplankton. For example, high turbidity could reduce UV-induced destruction of viruses, thereby increasing the viral load compared to other aquatic ecosystems. On the other hand, many viruses may never come into contact with a phytoplankton host because they are trapped by “non-host particles”, such as aggregates.

I also take into account the special characteristics of Elbe phytoplankton as a host. For example, data from a previous RTG project – specifically my doctoral thesis (see also: https://doi.org/10.1002/pei3.70014) – show that phytoplankton in the mid estuary has a smaller cell size. This has a direct impact on the probability of encounter between virus and host, as well as on the number of viruses released by a host cell.

2. What made you decide in favour of this field of research? What fascinates you about it, and what do you see as the biggest challenge?

I have been interested in the research topics of phytoplankton, viruses and the Elbe River since my studies. For example, I wrote my bachelor's thesis at the Hamburg Port Authority on the relationship between pollutant levels in Elbe sediments and the results of ecotoxicological tests (e.g. algae growth inhibition tests). In my master's thesis, I focused on viruses infecting green algae in the Baltic Sea. And in my doctoral thesis at RTG 2530, I dealt intensively with phytoplankton in the Elbe. I am particularly interested in phytoplankton because of its outstanding importance for carbon storage in aquatic ecosystems. I also find ecosystem modelling exciting because it allows many different scenarios to be analysed through mathematical descriptions of relationships. The possibilities here go beyond what can be measured through laboratory work. Of course, this also comes with challenges: incorrect assumptions or missing data can easily lead to false conclusions. It is therefore particularly important to critically question the results and validate them with data wherever possible.

3. What are your expectations of the collaboration in the Research Training Group 2530, and is there anything you are particularly looking forward to?

I am particularly pleased to be back at RTG 2530 after having already completed my doctoral thesis at RTG between 2020 and 2024. In particular, I hope to be able to attend the retreat again, exchange interesting findings, and continue to follow the progress of the project.