LandSeaLot Integration Labs: Spotlight on the Wadden Sea, Rhine Delta and Elbe Estuary
What is an Integration Lab?
LandSeaLot Integration Labs (LILs) are testing sites in which researchers and partners are developing a common strategy for observing land-sea interface areas throughout Europe. LILs are piloting new methods, technologies and community-based approaches to improve how we observe, study and understand essential areas like river mouths, estuaries and deltas. These observations provide key knowledge to scientific and stakeholder communities, enabling them to tackle important societal challenges.
Exploring the Wadden Sea, Rhine Delta and Elbe Estuary
The Wadden Sea is the largest intertidal sand and mud flat system on Earth, a shallow body of water traversed by wetlands and islands. It is located in the southeastern part of the North Sea, incorporating areas of Denmark, Germany and the Netherlands.
Recognised as a UNESCO World Heritage Site, it contains the Dutch, German and Danish Wadden Sea national parks and conservation areas. Two major adjacent rivers, the Rhine and the Elbe, contribute land-based sources to the Wadden Sea and help shape its unique ecosystem.
The Wadden Sea plays a critical ecological function as a carbon sink, meaning it can absorb and store carbon dioxide and help mitigate the effects of climate change. The potential of its coastal sediments, seagrasses and salt marshes to sequester carbon is an ongoing area of study.
About 3.5 million people live in this coastal region, with tourism on the islands and port towns being a significant source of employment. Ports in Germany, the Netherlands and Denmark also support industrial activities.
Pressures on the Area
Carbon and Nutrient Dynamics
Increased nutrient inputs from human activities like agriculture and industries on land can affect water quality in the land-sea interface, and often particularly in the coastal regions. This has led to problems like harmful algae blooms, increased phytoplankton (which can disrupt the marine food web), and the loss of seagrass (which is needed as a food source and habitat as well as a natural carbon storage system).
In the Wadden Sea-Elbe region human activities and geopolitical changes have significantly affected the land-sea interface ecosystem state and functioning since the 1980s and before, as researchers at the LIL have recently determined (Rewrie et al. 2023). These findings were also communicated to local stakeholders within LSL, generating a good discussion within the community. Now, the LIL is also investigating the current impacts of nutrient inputs to the Wadden Sea, Rhine and Elbe regions, also with relation to how this impacts the carbon dynamics, within the recovery state.
Responding to Pressures
Tracking nutrients from land to sea
The LIL is working to understand how rivers, streams, estuaries and seas move and cycle nutrients and materials such as sediment and plants, and how these materials in the water change from river to estuary to sea. Studying these elements of the water helps to determine how carbon and nitrogen, essential components in the water, change across the land-sea interface river and how factors like human activity might affect their fluctuations.
Developing a carbon budget
Researchers at the LIL aim to improve how carbon flux is calculated from land to sea, including estimates of influences by land-sea, sediment-water and water-air fluxes. While there is currently a carbon budget available for the Wadden Sea as part of the North Sea carbon budget, in the long term researchers are working to develop a carbon budgeting system that is specific and responsive to the Wadden Sea.
Understanding nutrients
The LIL will assess how nutrients entering and flowing through the area impact the production of organic matter and affect the overall health of the ecosystem.
Improving observations
By integrating in situ and remote sensing observations with models, the LIL is working to better understand and estimate how coastal zones store and release carbon and carbon dioxide. They will also work to establish FAIR data flows, making the resulting data free and accessible through integration into initiatives like Copernicus Marine Data Service and the ICOS data network.
New opportunities and collaborations
Growth of partnerships
The LIL team is working with SOOP (Shaping an Ocean of Possibilities), a Helmholtz Innovation platform that aims to strengthen ocean observation with the help of researchers, non-scientific stakeholders and the maritime industry. Together, they are developing technology to support citizen involvement in ocean observation, like a miniaturised measurement device called the SailingBox intended for use on everyday boats and yachts.
LIL researchers involved in SOOP have collaborated with another LandSeaLot partner, TransEuropeMarinas, to develop a marina-based ocean monitoring network and expand observations.
Use of emerging technology
The LIL is exploring the use of new tools, including cost-effective sensors, to increase observation of the regional land-sea interface. From Summer 2025, researchers will be testing low-cost sensors that can measure temperature, conductivity, light intensity and oxygen concentration alongside the ongoing use of high-cost sensors. These devices will be tested out on the water by boaters and canoers, who will report on the ease and applicability of these devices for scientists and local communities alike. And in shallow waters near tidal flats, the team will test the capacity of low-cost technology to validate satellite data that is being gathered on phytoplankton biomass (the amount of self-feeding plankton, which are a cornerstone of the marine ecosystem, that are present in the area).
Recent outputs and outreach
Researchers at the Wadden Sea, Rhine Delta and Elbe Estuary LIL recently published a paper (in Frontiers in Marine Science) and preprints (in EGUsphere and Biogeosciences) addressing carbon and nutrient fluxes and stocks in the area.
In Spring 2025, the team held a productive workshop with local stakeholders at the International Maritime Museum in Hamburg to discuss next steps. Topics discussed included improving exchange between inland and coastal communities, the integration of different observation methods and models, the status of nutrient reduction in the Wadden Sea, and how to best enable the free and accessible flow of data. These are crucial conversations as stakeholders work to engage the public, understand and adapt to climate change scenarios and continue to integrate their observation and management of the land-sea interface area.
Further Reading
Rewrie, LCV, B Baschek, JEE van Beusekom, A Körtzinger, W Petersen, R Röttgers, YG Voynova. Quantifying the impact of primary production and net ecosystem metabolism on carbon and nutrient cycling at the land-sea interface, Frontiers in Marine Science, 12, 2025, https://oceanrep.geomar.de/id/eprint/62166/
Meyer, J., YG Voynova, B Van Dam, B., L Luitjens, D Daehne, and H Thomas. Intertidal regions regulate seasonal coastal carbonate system dynamics in the East Frisian Wadden Sea, EGUsphere [preprint], https://doi.org/10.5194/egusphere-2024-3048, 2024, Biogeosciences, in review
Macovei, VA, LCV Rewrie, R Röttgers, YG Voynova. Spring-neap tidal cycles modulate the strength of the carbon source at the estuary-coast interface, Biogeosciences, preprint, doi:10.5194/egusphere-2024-2643, accepted, in production
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