PhD Dr Rhena Schumann, head of the Biological Station Zingst at Rostock University, is leading the project “Plankton Diversity in a Eutrophic Baltic Coastal Lagoon”. The initiative builds on decades of phyto- and zooplankton monitoring in the Darß-Zingst Bodden Chain, a eutrophic coastal lagoon on the southern Baltic coast. Despite reductions in nutrient inflows, phytoplankton communities remain largely unchanged, influenced by shallow waters, limited ocean exchange, and fluctuating salinity.
The interview was recorded during the exclusive Data Training Workshop in Paris (3–5 June 2025). This immersive event brought together experts and project teams for hands-on sessions in data transformation, quality control, metadata management, and collaborative discussions, refining methodologies and strengthening connections across the growing marine biodiversity data network.
Read the full written interview
Who are you, and what is the name of your institute?
I’m Rhena Schumann from Rostock University, and I’m the head of the Biological Station Zingst. I studied marine biology many years ago. The station is located on the southern Baltic coast, in an inner coastal lagoon of brackish water — a heavily eutrophied system.
In the 1960s, a monitoring program was established by the state agency together with Rostock University. It started with simple hydrology measurements and gradually expanded to include water chemistry, nutrients, and later organisms such as phytoplankton, zooplankton, bacteria, and benthic species. While the program itself is no longer active, it generated decades of valuable biodiversity data.
What challenges are associated with managing such long-term biodiversity data?
Biodiversity data are complex — a single sample can contain many different organisms. Publishing and sharing these data isn’t straightforward. We need reliable repositories to store them, both for others to access and for us to use collaboratively with other scientists. This allows us to better interpret the long-term trends and patterns in the ecosystem.
What have you learned about the plankton communities in this lagoon?
There’s a common assumption that cyanobacteria — or blue-green algae — are harmful because they can produce toxins and fix nitrogen, helping them persist in nutrient-limited environments. However, we discovered about ten years ago that the cyanobacteria in our lagoon don’t produce toxins and likely cannot fix nitrogen because they lack the genes for it.
Still, these cyanobacteria can have a long-term negative impact on the underwater environment. Once established, they can persist for a very long time, and the recovery of the system is slower than expected. Understanding this helps set realistic expectations for restoration efforts.
Why is long-term monitoring important?
Monitoring is valuable in itself. It allows us to see how ecosystems respond over time and provides insights for similar systems elsewhere. Lagoons like ours are common along the southern Baltic coast and worldwide, so what we learn here can be applied broadly.
How do you see your role as a data provider?
I collect and process the samples — not many people are doing this work. Now that we have decades of data, it’s important to make them available to others. I’m learning how to manage and share these data effectively, which is why I participated in the training.
Have you been involved with initiatives like the Digital Twin of the Ocean?
I didn’t know much about the Digital Twin before, but the Biological Station is part of the LTER consortium (Long-Term Ecological Research). LTER emphasises data repositories at a global scale, but there’s still a gap in how to provide data in a way that’s accessible and interoperable. I hope that by depositing our data in one system, it can be harvested and used by others automatically, bridging that gap.