Bioaerosols in the Amazon rain forest: Temporal variations and vertical profiles of Eukarya, Bacteria and Archaea

Prass, Maria; Andreae, Meinrat O.; Araújo, Alessandro; Artaxo, Paulo; Ditas, Florian; Elbert, Wolfgang; Franco, Marco Aurélio; Angelis, Isabella Hrabě de; Kesselmeier, J.; Klimach, Thomas; Kremper, Leslie Ann; Thines, Eckhard; Walter, David; Weber, J.; Weber, Bettina; Fuchs, Bernhard M.; Pöschl, Ulrich; Pöhlker, Christopher

doi:10.5194/bg-2020-469

Cited by 6 publications

(8 citation statements)

References 39 publications

(53 reference statements)

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“…Attempts to analyze the microbial content of the vertical air column date back to the early 20th century when aviation pioneers such as Charles Lindberg conducted the Skyhook experiments (6)(7)(8)(9)(10). Other vertical experimental designs resorted to air sampling on mountains with high elevation (11)(12)(13), low-height sampling at research towers (14), or meteorological balloons (15). In parallel to addressing the issues associated with vertical sampling, more recent studies have advanced the field taxonomically with molecular biological approaches, while still being challenged by limiting amounts of airborne biomass (16,17).…”

mentioning

confidence: 99%

Vertical stratification of the air microbiome in the lower troposphere

Drautz–Moses

Luhung

Gusareva

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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The troposphere constitutes the final frontier of global ecosystem research due to technical challenges arising from its size, low biomass, and gaseous state. Using a vertical testing array comprising a meteorological tower and a research aircraft, we conducted synchronized measurements of meteorological parameters and airborne biomass (n = 480) in the vertical air column up to 3,500 m. The taxonomic analysis of metagenomic data revealed differing patterns of airborne microbial community composition with respect to time of day and height above ground. The temporal and spatial resolution of our study demonstrated that the diel cycle of airborne microorganisms is a ground-based phenomenon that is entirely absent at heights >1,000 m. In an integrated analysis combining meteorological and biological data, we demonstrate that atmospheric turbulence, identified by potential temperature and high-frequency three-component wind measurements, is the key driver of bioaerosol dynamics in the lower troposphere. Multivariate regression analysis shows that at least 50% of identified airborne microbial taxa (n = ∼10,000) are associated with either ground or height, allowing for an understanding of dispersal patterns of microbial taxa in the vertical air column. Due to the interconnectedness of atmospheric turbulence and temperature, the dynamics of microbial dispersal are likely to be impacted by rising global temperatures, thereby also affecting ecosystems on the planetary surface.

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mentioning

confidence: 99%

Vertical stratification of the air microbiome in the lower troposphere

Drautz–Moses

Luhung

Gusareva

et al. 2022

Proc. Natl. Acad. Sci. U.S.A.

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“…1. A spectrum of biogenic emissions from the rain forest ecosystem, including the release of primary biological aerosol particles (i.e., pollen, spores, bacteria, fragments) (e.g., Pöhlker et al, 2012;Huffman et al, 2012;Löbs et al, 2020;Prass et al, 2021) as well as the emission of biogenic VOCs followed by their atmospheric oxidation and conversion into secondary organic aerosols (SOA) (e.g., Chen et al, 2015;Liu et al, 2016;Saturno et al, 2018a;Leppla et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Occurrence and growth of sub-50 nm aerosol particles in the Amazonian boundary layer

Franco

Ditas

Kremper

et al. 2021

Preprint

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Abstract. New particle formation (NPF), referring to the nucleation of molecular clusters and their subsequent growth into the cloud condensation nuclei (CCN) size range, is a globally significant and climate-relevant source of atmospheric aerosols. Classical NPF exhibiting continuous growth from a few nanometers to the Aitken mode around 60–70 nm is widely observed in the planetary boundary layer (PBL) around the world, but not in central Amazonia. Here, classical NPF events are rarely observed in the PBL, but instead, NPF begins in the upper troposphere (UT), followed by downdraft injection of sub-50 nm (CN< 50) particles into the PBL and their subsequent growth. Central aspects of our understanding of these processes in the Amazon have remained enigmatic, however. Based on more than six years of aerosol and meteorological data from the Amazon Tall Tower Observatory (ATTO, Feb 2014 to Sep 2020), we analyzed the diurnal and seasonal patterns as well as meteorological conditions during 254 of such Amazonian growth events on 217 event days, which show a sudden occurrence of particles between 10 and 50 nm in the PBL, followed by their growth to CCN sizes. The occurrence of events was significantly higher during the wet season, with 88 % of all events from January to June, than during the dry season, with 12 % from July to December, probably due to differences in the condensation sink (CS), atmospheric aerosol load, and meteorological conditions. Across all events, a median growth rate (GR) of 5.2 nm h−1 and a median CS of 0.0011 s−1 were observed. The growth events were more frequent during the daytime (74 %) and showed higher GR (5.9 nm h−1) compared to nighttime events (4.0 nm h−1), emphasizing the role of photochemistry and PBL evolution in particle growth. About 70 % of the events showed a negative anomaly of the equivalent potential temperature (∆θ'e) – as a marker for downdrafts – and a low satellite brightness temperature (Tir) – as a marker for deep convective clouds – in good agreement with particle injection from the UT in the course of strong convective activity. About 30 % of the events, however, occurred in the absence of deep convection, partly under clear sky conditions, and with a positive ∆θ'e anomaly. Therefore, these events do not appear to be related to downdraft injection and suggest the existence of other currently unknown sources of the sub-50 nm particles.

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“…Long-term measurements of aerosol physical and chemical properties are then presented, and a complementary approach is described to obtain aerosol properties under clean atmospheric conditions (empiric pristine). The results of this chapter were presented at a series of international conferences (shown in Appendix A.1), and some results are already partially published in scientific peer-reviewed articles in which I have co-authorship PRASS et al, 2021). In Figure 39, the seasonal characteristic of the aerosol properties is evident, following other studies in the literature for Amazonian aerosols (RIZZO et al, 2011;RIZZO et al, 2013;SATURNO et al, 2018b).…”

Section: Vertical Gradient Of Aerosol Physicochemical Propertiesmentioning

confidence: 56%

“…1. A broad spectrum of biogenic emissions from the rain forest ecosystem exists, which includes the release of primary biological aerosol particles (e.g., pollen, spores, bacteria, fragments) LÖBS et al, 2020;PRASS et al, 2021) as well as the emission of biogenic VOCs followed by their atmospheric oxidation -e.g., in the course of lightning (TOLEDO MACHADO et al, 2021) -and conversion into SOA SATURNO et al, 2018a;LEPPLA et al, 2021).…”

Section: New Particle Formation and Aerosol Life Cycle In Central Amazoniamentioning

confidence: 99%

“…1. A spectrum of biogenic emissions from the rain forest ecosystem, including the release of primary biological aerosol particles (i.e., pollen, spores, bacteria, fragments) (e.g., Löbs et al, 2020;Prass et al, 2021) as well as the emission of biogenic VOCs followed by their atmospheric oxidation and conversion into secondary organic aerosols (SOA) (e.g., Saturno et al, 2018a;Leppla et al, 2021).…”

Section: Future Perspectivesmentioning

confidence: 99%

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Vertical transport, growth processes, and aerosol characterization in Amazonia

Franco¹

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The Amazon Tall Tower Observatory (ATTO) is a laboratory located in a primary forest region in the Central Amazon, ideal for studying the aerosol properties in the vertical profile, particularly at heights of 60 and 325 m from the ground. In this work, we identify and characterize the processes that control the aerosol population, their physicochemical properties, and the growth of particles in the vertical profile of the boundary layer. Measurements of particle number size distribution, scattering, and radiation absorption were used and the chemical composition of aerosols, together with remote sensing data. The analysis of the occurrence of aerosol particles growth was focused on particles from 10 to 50 nm, with measurements between February 2014 and September 2020. It was observed that in 14 % of the analyzed period (217 in 1596 days) we identified particle growth events, with 88 % of them occurring in the wet season. The diurnal cycle of growth frequency showed that 74 % of them occur during the day, indicating an association with photochemistry and boundary layer evolution.The median growth event rate was 5.2 nm h −1 , and the condensation sink during growth was 0.0011 s −1 . The relationship of growth events with meteorological variables showed that most event onsets coincide with the occurrence of descending convective currents (63 %). The aerosol chemical composition is mainly dominated by the organic fraction, with 80 % of the mass of PM 1 . Organic aerosols are determinants of the aerosol scattering coefficient. The average absorption and scattering coefficients, σ abs,637nm and σ scat ,525nm , under atmospheric conditions without significant anthropogenic impacts were 0.14 Mm −1 and 4.4 Mm −1 , respectively. Apparent differences in aerosol physical properties between 60 and 325 m in height were observed for σ scat ,525nm , and aerosol volume. A strong spectral dependence of the mass scattering efficiencies with the incident radiation wavelength was observed, and, in particular, they were significantly larger at 60 m, showing that the aerosol population close to the canopy is more effective in scattering the radiation. In contrast the mass absorption efficiency is similar at the two heights. It was observed that the concentration of aerosols smaller than 50 nm increases with increasing convective activity and lightning occurrence. It was observed that 72 % of aerosol particle transport events occur first at 325 m, which is expected for processes dominated by convective downward currents. In contrast 28 % of the events started at 60 m, and only later were detected at 325 m. The results support the hypothesis of a source of aerosols smaller than 50 nm close to the canopy. We show that the physical characteristics of aerosols at heights of 60 and 325 m are different, with those closest to the canopy being dominated by biogenic emissions and those at 325 m being more processed and influenced by long-range transport.

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Bioaerosols in the Amazon rain forest: Temporal variations and vertical profiles of Eukarya, Bacteria and Archaea

Cited by 6 publications

References 39 publications

Vertical stratification of the air microbiome in the lower troposphere

Vertical stratification of the air microbiome in the lower troposphere

Occurrence and growth of sub-50 nm aerosol particles in the Amazonian boundary layer

Vertical transport, growth processes, and aerosol characterization in Amazonia

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