Tandem Fluorescence Measurements of Organic Matter and Bacteria Released in Sea Spray Aerosols

Abstract

Biological aerosols, typically identified through their fluorescence properties, strongly influence clouds and climate. Sea spray aerosol (SSA) particles are a major source of biological aerosols, but detection in the atmosphere is challenging due to potential interference from other sources. Here, the fluorescence signature of isolated SSA, produced using laboratory-based aerosol generation methods, was analyzed and compared with two commonly used fluorescence techniques: excitation–emission matrix spectroscopy (EEMS) and the wideband integrated bioaerosol sensor (WIBS). A range of dynamic biological ocean scenarios were tested to compare EEMS and WIBS analyses of SSA. Both techniques revealed similar trends in SSA fluorescence intensity in response to changes in ocean microbiology, demonstrating the potential to use the WIBS to measure fluorescent aerosols alongside EEMS bulk solution measurements. Together, these instruments revealed a unique fluorescence signature of isolated, nascent SSA and, for the first time, a size-segregated emission of fluorescent species in SSA. Additionally, the fluorescence signature of aerosolized marine bacterial isolates was characterized and showed similar fluorescence peaks to those of SSA, suggesting that bacteria are a contributor to SSA fluorescence. Through investigation of isolated SSA, this study provides a reference for future identification of marine biological aerosols in a complex atmosphere.

Fluorescent biological aerosol particles over the central Pacific Ocean: covariation with ocean surface biological activity indicators

“…As a result, high wind speeds resulted in an increase in the number concentrations of bioaerosols as wind-driven transportation of TEP and bacteria from the sea surface to the atmosphere occurred efficiently. Our interpretation is consistent with Santander et al (2021), where the dominance of bacteria in fluorescent sea spray aerosols was confirmed with laboratory-generated aerosol particles and seawater.…”

“…A previous study characterizing fluorescence patterns of a variety of bioaerosols (bacteria, fungi, spore, and pollen) using laboratory experiments showed that Type A particles originated from bacterial and fungi species (Hernandez et al, 2016). Similar results were found with marine bacteria (Santander et al, 2021). Therefore, we infer that bacteria (and fungi, if present) at the sea surface were transported into the atmosphere by wind and were detected as fluorescent particles in the atmosphere.…”

“…These small FAPs may be related to most of the marine bacteria detected by flow cytometry, whose size was mostly < 2 µm. The size was slightly smaller than that reported for the Type A particles (identified as bacteria), ∼ 2-3 µm, generated with coastal seawaters (Santander et al, 2021). Correlations of the time series of fluorescent particle abundance with biogenic indicators in surface seawater are discussed in Sect.…”

Leaching Material from Antarctic Seaweeds and Penguin Guano Affects Cloud-Relevant Aerosol Production

“…One of the major challenges in understanding the dynamics of primary sea spray production is the role of biogenic organic matter (OM) from the surface ocean. A chemoselective transfer of OM from the ocean to the atmosphere is often observed, meaning that some organic compounds are transported to the atmosphere to a larger extent than others (Quinn et al, 2015;Miyazaki et al, 2018;Santander et al, 2021). Here, we have shown that OM have an effect on aerosol particle production rates, which in turn can influence cloud properties, and may therefore be important for the changing climate.…”

Sea Ice Microbiota in the Antarctic Peninsula Modulates Cloud-Relevant Sea Spray Aerosol Production

“…For example, Miyazaki et al (2018) showed a consistent enrichment in humic fluorescence with respect to protein fluorescence when comparing SSAs to their respective source water (123-410%). Santander et al (2021) also observed that during the degradation of a simulated phytoplankton bloom, increases in protein fluorescence of bulk seawater were not reflected in an increment of protein-like fluorescence in SSA aerosols, whereas humic fluorescence presented coupled increases in both bulk seawater and SSAs. The changes in dissolved organic matter fluorescence observed during our experiments suggest that not only phytoplankton production but also microbial processing of freshly released DOM may affect aerosol production.…”