Spatial distribution of Sea-spray aerosols' viable prokaryotes and virus-like particles during RV METEOR cruise M197, Eastern Mediterranean Sea

We quantified the abundance of viable (live) microbes and virus-like cells in freshly generated sea-spray. To this end, we pumped surface seawater during a month-long cruise across the Eastern Mediterranean Sea (Jan-Feb. 2024, RV. Meteor cruise ID M197). We determined how microbial viability changes once they are transferred from surface water into sea-spray. Our results show that the number of live bacteria in sea-spray corresponds to chlorophyll-a in surface water, a measure algal biomass and inversely corresponds to surface water temperatures. The higher the algal biomass in surface water the higher microbial viability in sea-spray was observed. In contrast, viruses showed the opposite trend, being more common in areas of oligotrophic conditions characterized by low algal biomass. When comparing sea-spray to the surface water from which it originated, we found that about 15% of the microbes died in the process of becoming airborne. Those that survived the aerosolization and remained alive were just as productive as those in the surface seawater. This study gives a better understanding of what happens to marine microbes when they get into the air via sea spray and how they might impact the environment.