Sea surface microlayer mediated exchange between the aerobiome and the Pacific Ocean

Microbes are globally ubiquitous and play a crucial role in ecological network systems and global cycles (e.g., the carbon, nitrogen, water cycles). Hundreds of trillions of microorganisms are estimated to be exchanged between the marine and atmospheric environments, due to the vastness of the sea–air interface. The sea surface microlayer (SML) serves as the interface between the ocean and the atmosphere and is a unique ecosystem for microbial life. The aerosolized microbes may affect ocean ecology, global cycles, and promote genetic exchange between ecosystems. However, little is known about the mechanisms controlling microbial exchange between the environments, and the viable state and metabolic activity of marine bioaerosols. This study aims to characterize the microbial communities of the three environments (surface water-SML-atmosphere) and explore possible linkages between them, by developing a simple and repeatable technique for sampling the SML. We will present the validation of our new SML sampling method, based on surface water sub-sampling, using cell and genomic analyses. This method may provide a substantial improvement compared to direct sampling from the sea, ensuring stabilization without unexpected disturbances. In addition, we will present our results on the linkages between marine, SML and atmospheric microbial communities using our new SML sampling technique, from samples collected in the Pacific Ocean. Our results exhibit different clustering patterns for the three proximal environments, supports their identification as distinct environments with distinct microbial signatures. However, the SML is visualized as an “average” between surface water and air samples both in clustering tightness and location, displays its role as an exchange medium between the ocean water and the marine atmospheric boundary layer. This study contributes to improving understanding of the role of the SML in emission of primary aerosols, leading to better characterization of the ocean-atmosphere interactions and allows for better assessments of their contribution to global cycles and the marine ecosystem.