Cultivable halotolerant ice-nucleating bacteria and fungi in coastal precipitation

Abstract. Ice-nucleating particles (INPs) represent a rare subset of aerosol that initiate cloud droplet freezing at temperatures above the homogenous point water (−38 ∘C). Considering ocean covers 71 % Earth's surface and represents large potential source INPs, it is imperative identities, properties relative emissions INPs become better understood. However, specific underlying drivers marine INP remain largely unknown due to limited observations challenges associated with isolating INPs. By generating isolated nascent sea spray (SSA) over range biological conditions, mesocosm studies have shown microbes can contribute Here, we identify 14 (30 %) cultivable halotolerant ice-nucleating fungi among 47 total isolates recovered from precipitation samples collected in coastal air southern California. (IN) were nucleated ice extremely warm moderate (−2.3 −18 While some Gammaproteobacteria are known nucleate as high −2 ∘C, Brevibacterium sp. first Actinobacteria found be capable nucleation relatively temperature Air mass trajectory analysis demonstrates sources dominant during all sampling periods, phylogenetic indicates least 2 IN closely related taxa. Moreover, results cell-washing experiments demonstrate most maintained activity absence nutrients cell growth media. This study supports previous implicated additionally links between precipitation, microbes.