Researchers from the Leibniz Institute for Tropospheric Research (TROPOS) and partner institutions used the BELUGA tethered balloon to collect air samples at 300 to 1,000 meters altitude near Ny-Ålesund, Svalbard, during autumn 2021 and spring 2022. Filter samples were analyzed alongside seawater and surface-film samples from Kongsfjorden, allowing the team to directly trace the transport of marine carbohydrates from the ocean into the lower troposphere for the first time.
Sea-spray aerosol particles, generated by breaking waves and bursting bubbles, carry inorganic salts and organic material including complex polysaccharides produced by algae and bacteria. Previous laboratory work by TROPOS in 2025 showed these polysaccharides significantly affect the ice-nucleating activity of sea-spray particles, particularly at temperatures between –20°C and –15°C in remote ocean regions where terrestrial ice-nucleating particles are scarce.
Until now, measurements of marine sugars were limited to ship-based sampling at sea level and a few mountain-top observations. Vertically resolved data from mobile platforms had been entirely absent, leaving the atmospheric significance of these compounds uncertain. The balloon campaign filled this gap by capturing the vertical distribution of marine carbohydrates across altitudes relevant to cloud formation.
The analysis also revealed evidence that sugars may form or transform within the atmosphere itself. Under very humid conditions, particularly in clouds with precipitation, the researchers observed molecular signatures suggesting in-situ production or alteration of carbohydrates, potentially linked to the metabolism of airborne microorganisms.
Dr. Sebastian Zeppenfeld of TROPOS said the findings indicate the atmosphere is "much more alive than we had long thought" and that marine organic matter plays a more dynamic role in the Arctic climate system than previously assumed. The vertical transport of these ice-nucleating particles has direct implications for cloud microphysics, radiative properties, and precipitation formation.
As Arctic warming continues and sea ice retreats, the flux of sea-spray aerosols and their organic components is expected to increase. The research team plans to extend measurements to the Southern Ocean during the 2028 Polarstern expeditions as part of the Antarctica-Insync project, providing a bipolar perspective on marine carbohydrate cycling.
The study, led by TROPOS with contributions from the University of Cologne, Alfred Wegener Institute, Max Planck Institute for Marine Microbiology, University of Oldenburg, and University of Bremen, was published in Atmospheric Chemistry and Physics. It forms part of the German Research Foundation's Transregio 172 program investigating Arctic climate change.
Arctic balloon samples trace marine sugars from the ocean to cloud-forming heights
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