Airborne Prokaryote and Virus Abundance Over the Red Sea

Abstract

Aeolian dust exerts a considerable influence on atmospheric and oceanic conditions negatively impacting human health, particularly in arid and semi-arid regions like Saudi Arabia. Aeolian dust is often characterized by its mineral and chemical composition; however, there is a microbiological component of natural aerosols that has received comparatively little attention. Moreover, the amount of materials suspended in the atmosphere is highly variable from day to day. Thus, understanding the variability of atmospheric dust loads and suspended microbes throughout the year is essential to clarify the possible effects of dust on the Red Sea ecosystem. Here, we present the first estimates of dust and microbial loads at a coastal site on the Red Sea over a 2-year period, supplemented with measurements from dust samples collected along the Red Sea basin in offshore waters. Weekly average dust loads from a coastal site on the Red Sea ranged from 4.6 to 646.11 μg m −3 , while the abundance of airborne prokaryotic cells and viral-like particles (VLPs) ranged from 77,967 to 1,203,792 cells m −3 and from 69,615 to 3,104,758 particles m −3 , respectively. To the best of our knowledge, these are the first estimates of airborne microbial abundance in this region. The elevated concentrations of resuspended dust particles and suspended microbes found in the air indicate that airborne microbes may potentially have a large impact on human health and on the Red Sea ecosystem.

The Relationship between Air-Mass Trajectories and the Abundance of Dust-Borne Prokaryotes at the SE Mediterranean Sea

“…A more detailed comparison between Our measurements show that heterotrophic and autotrophic (cyanobacteria) airborne prokaryotes were abundant throughout the study period (2015-2018, Figure 3). Heterotrophic prokaryotic microorganisms ranged from 188-30,601 cells m −3 air ( Figure 3A), in accordance with measurements taken throughout the Atlantic [12,32], Pacific and Indian oceans [12], and the Sea of Japan [33], yet lower by an order of magnitude than recently reported in the central Red Sea [34] (Figure 4). The variability in the prokaryotic cell abundances may be attributed to the distance from nearby shore/land [12], the atmospheric route (i.e., height, duration), the concentration of dust/aerosol, as well as to differences in methodology of aerosol collection and procedure for assessing cell numbers (i.e., microscopy, qPCR, culture-based methods) [12,33,35].…”

“…Compilation of airborne prokaryotes abundance over the oceans. Data was compiled from References[12,[32][33][34] and this study. Box-Whisker plots show the interquartile range (25th-75th percentile) of the data set.…”

Aerosol Microbiome over the Mediterranean Sea Diversity and Abundance

“…The lowest abundances were measured in the Central and Eastern Mediterranean (6.64 × 10 3 to 7.17 × 10 3 cells m −3 air) in samples 9 and 4, respectively. Bacterial abundances in aerosols collected over the MS were in agreement with previous studies from the eastern Mediterranean coast [10] and the Atlantic, Pacific, and Indian ocean basins [1], yet were lower than those reported in the East China Sea [54] and the Red Sea [55]. Rahav et al [10] measured the abundance of airborne prokaryotes at a coastal site located at the easternmost MS during 34 sampling events (between 2015 and 2018) and found that abundances were positively correlated to the concentration of aerosols in the air (mg m −3 air).…”

“…'Common' organisms found over the Mediterranean Sea in this study compared to five studies focusing on marine aerosols [1,8,38,55,56], five studies focusing on coastal aerosols [3,31,32,57,58], and six samples from one study focusing on Mediterranean surface seawater [59]. Columns under open ocean studies refer to references [1,8,38,55,56], columns under Mediterranean coastal studies refer to references [3,31,32,57,58], and columns under Mediterranean seawater samples refer to six samples from reference [59]. To quantitatively assess the diversity and estimate the differences in airborne bacterial communities over the MS, we report microbial community richness, expressed as the number of unique OTUs observed, and diversity expressed as Shannon's diversity index (H), estimated from the abundance of bacteria in each sample (Table 1).…”

The environmental drivers of bacterial meningitis epidemics in the Democratic Republic of Congo, central Africa

“…Then, altitude constitutes another important environmental parameter in the development of meningitis in the DRC, with lower altitude areas like large plains and river catchment areas favoring the development of the bacterial disease. The role of altitude could be explained by long-distance transport of dust in upper layers of the atmosphere that may expose microbes to challenging conditions [38]. For example in the epidemiology of malaria, the incidence of cases decreases when altitude increases [39,40].…”