In July 2024, the BASS team conducted a month-long field campaign aboard RV Heincke and MS Fritz-Reuter, operating out of Heligoland. Each day, the team set out to locate slick conditions in the North Sea. Slicks form when the Sea-Surface Microlayer (SML) becomes particularly enriched with organic material. As a result, small capillary waves are dampened, creating a visibly smooth and distinct sea surface. To study these conditions, the catamarans HALOBATES and GLAUCUS ATLANTICUS were deployed from the research vessels to sample both the SML and the underlying water. Additional instruments, including a drifting sensor chain, drifters, a pCO₂ measuring system, and the aircraft Jade One from Jade University of Applied Sciences, complemented the mission—providing a comprehensive view of the oceanographic conditions from both sea level and above.

Credit:
Contributers: BASS group
Filmmaker: Thom Hoffmann

The sea surface microlayer (SML) is the boundary layer between the atmosphere and ocean, spanning the uppermost ~1 mm of the ocean. The SML is typically enriched with organic matter and microbial cells creating a distinct organic film between the ocean and atmosphere. The existence of the SML is a global phenomenon, and due to its unique position, all material and energy exchanged between the ocean and atmosphere has to pass through this interfacial boundary layer. A new emerging consensus in the literature describes the SML as biofilm-like and microbial-rich habitat. The global prevalence of the SML, its unique position between the ocean and atmosphere and re-current biofilm-like features has recently pushed the SML into a central role in ocean and climate science.

Credit:
Contributers: BASS group
Filmmaker: Thom Hoffmann