investigating the wind wake from a offshore wind farm

Project PI: Göran Broström, Anis El Youncha, Department of Marine Science, University of Gothenburg and Thomas Dahlgren NORCE Norwegian Research Centre/Department of Marine Science, University of Gothenburg

The project was supported by VOTO by deploying a sailbuoy outside the Kriegers flak Offshore Wind Farm (OWF) in 2024. The sailbuoy functioned well during the campaign and we got data as expected. We compare observations from the sailbuoy with observations from the nearby FINO2 oceanographic and meteorological platform. Observations show that sailbuoy provided essentially good values. We see a drift in surface water salinity at the end of the campaign, and the wind speed has a large scatter. The latter implies that we are hesitant to say that we can detect the wind wake from the OWF’s at Kriegers flak and any significant impact on e.g. ocean stratification or mixing. We also compared observations with results from a meteorological model dataset (NORA3 from Norwegian Meteorological Institute), and from an ocean model available at the marine Copernicus web site. Observations compare quite well, but also show a large natural variability in both ocean and atmospheric fields that hampers a detailed analysis of the atmospheric and oceanic response from the OWF.

Photo: Marcus Melin, VOTO.

Photo: Robin Claesson, Midocean

Discovery and quantification of maerl beds – one of sweden’s most unknown marine habitats

Project PI: Lina Rasmusson & Emily Stragapede, Department of Biological and Environmental Sciences, University of Gothenburg.

This report presents the findings of a field-based study aimed at mapping and characterizing maerl beds in the offshore Fladen Bank on the Swedish west coast. Maerl, a free-living coralline red algae, forms structurally complex habitats that support high biodiversity but remain poorly documented in Swedish waters. Using a combination of multibeam echosounder (MBES) acoustic mapping and visual ground-truthing via remotely operated vehicle (ROV) and drop cameras, the study assessed habitat composition, biodiversity, and the feasibility of acoustic detection of maerl. Results show that maerl beds are heterogeneous and typically occur mixed with other substrates, supporting diverse macrofauna and flora. However, correlations between acoustic backscatter and maerl cover were weak, indicating that further methodological refinement is needed. This is an ongoing process. The study contributes to improved understanding and monitoring approaches for this vulnerable and ecologically important habitat.

Semi-instantaneous in-situ measurements across air-sea interface for study and monitoring air-sea interactions in the Baltic Sea.

Project PI: Dariusz Baramowski, Institute of Geophysics Polish Academy of Sciences

This project aimed to fill an observational gap across the air–sea interface through the use of an Uncrewed Aerial Vehicle (UAV) capable of both air and water measurements. This gap exists because typical manned or autonomous measurements are confined either to the atmosphere or to the water environment, or they operate solely at the interface. As a result, no operational monitoring system is currently capable of observing vertical variability in both atmospheric and oceanic properties simultaneously.
The goal of the project was to develop a UAV‑based measurement system and use it to monitor diurnal evolution across the air–sea interface in the Baltic Sea, specifically from 10 m below the water surface up to 120 m in the atmosphere. This vertical range is critical for understanding coupled variability between the atmosphere and the ocean, which is strongly influenced by diurnal processes.

Photo: Andrew Birkett, VOTO.

Sunken pasts – Mapping the seabed of Sweden’s southern coast

As Sweden’s land rebounded after the last Ice Age, ancient shorelines were submerged. With the backing of Ocean Support, seabed surveys along the country’s southern coast are uncovering traces of prehistoric life and lost landscapes under the sea.

Pelagic fish surveys with Sail buoys in Hudson Bay.

Project PI: Jonas Hentati Sundberg, Sveriges Lantbruks Universitet

Seabirds are an essential parts of healthy and vibrant marine ecosystems. Being at the top of marine food chains, they are susceptible to various human-induced threats including climate change and overfishing. This project was aimed at quantifying the amounts of prey available to breeding populations of seabirds. Research was conducted across three contrasting ecosystems: Hudson Bay, Canada, Baltic Sea and Bass Strait, Australia. VOTO has supported the field work using a Sail buoy deployed off Coats island in Hudson Bay June – July 2024. The expected outcome is more detailed knowledge on prey amount and distribution required to conserve seabird populations. 

Photo: Marcus Melin, VOTO

Turbomix: Glider-based microstructure observations in Bornholm Basin

Project PI: Anna Bulczak, Researcher at Institute of Oceanology Polish Academy of Sciences.

The TurboMix project was designed to investigate the possibility to study turbulent mixing in a highly stratified sea using an autonomous underwater glider equipped with a microstructure sensor.

The project started in 2023 with the purchase and integration of a Rockland Microstructure sensor on a VOTO SeaExplorer glider. During 2024 and 2025, VOTO conducted 5 glider missions in the Bornholm Basin. Each mission was between 14 and 20 days of continuous glider profiling, collecting valuable data for the project.