Interannual Variability in the Source Location of North African Dust Transported to the Amazon

Barkley, Anne E.; Pourmand, A.; Longman, Jack; Sharifi, Arash; Prospero, Joseph M.; Panechou, Kathy; Bakker, Natalie; Drake, Nick; Guinoiseau, Damien; Gaston, Cassandra J.

doi:10.1029/2021gl097344

Cited by 13 publications

(4 citation statements)

References 82 publications

(169 reference statements)

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“…Measurements like ours are needed over longer timeframes, which can serve as a baseline with which to elucidate future changes. The strategy used in our study can be directly implemented to study Saharan dust transported to other receptor regions, e.g., South America, − the Middle East, and Europe, all of which are frequently impacted by African dust. In these cases, the dust may originate in different African source regions, travel by different paths, and occur in different seasons. , This is particularly important because of the interplay between climate, which influences the potential African source areas (and thereby its characteristics) and the role of dust in climate forcing. , …”

Section: Implications and Future Workmentioning

confidence: 99%

“…In these cases, the dust may originate in different African source regions, travel by different paths, and occur in different seasons. 99 , 101 This is particularly important because of the interplay between climate, which influences the potential African source areas (and thereby its characteristics) and the role of dust in climate forcing. 12 , 40 …”

Section: Implications and Future Workmentioning

confidence: 99%

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Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas

Das,

McEwen,

Prospero

et al. 2023

Environ. Sci. Technol.

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Although airborne bacteria and fungi can impact human, animal, plant, and ecosystem health, very few studies have investigated the possible impact of their long-range transport in the context of more commonly measured aerosol species, especially those present in an urban environment. We report first-of-kind simultaneous measurements of the elemental and microbial composition of North American respirable airborne particulate matter concurrent with a Saharan−Sahelian dust episode. Comprehensive taxonomic and phylogenetic profiles of microbial communities obtained by 16S/18S/ITS rDNA sequencing identified hundreds of bacteria and fungi, including several cataloged in the World Health Organization's lists of global priority human pathogens along with numerous other animal and plant pathogens and (poly)extremophiles. While elemental analysis sensitively tracked long-range transported Saharan dust and its mixing with locally emitted aerosols, microbial diversity, phylogeny, composition, and abundance did not well correlate with the apportioned African dust mass. Bacterial/fungal diversity, phylogenetic signal, and community turnover were strongly correlated to apportioned sources (especially vehicular emissions and construction activities) and elemental composition (especially calcium). Bacterial communities were substantially more dissimilar from each other across sampling days than were fungal communities. Generalized dissimilarity modeling revealed that daily compositional turnover in both communities was linked to calcium concentrations and aerosols from local vehicles and Saharan dust. Because African dust is known to impact large areas in northern South America, the Caribbean Basin, and the southern United States, the microbiological impacts of such long-range transport should be assessed in these regions.

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Section: Implications and Future Workmentioning

confidence: 99%

Section: Implications and Future Workmentioning

confidence: 99%

Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas

Das,

McEwen,

Prospero

et al. 2023

Environ. Sci. Technol.

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“…Deserts and arid zones present the lowest species richness among the Earth's biomes (Hughes et al, 2021). Biased by this poor diversity, we tend to perceive desert biomes as vast and homogeneous environments devoid of life, which consequently attract less research and conservation interest (Durant et al, 2012) despite providing key global ecosystems services (e.g., climate regulation [Barkley et al, 2022]). However, many deserts experienced a dynamic geological past (Pepper & Keogh, 2021) that generated high levels of endemism (Šmíd et al, 2021) and unique biodiversity adaptations to aridity (Ward, 2016).…”

Section: Introductionmentioning

confidence: 99%

Overlooked species diversity in the hyper‐arid Sahara Desert unveiled by dryland‐adapted lizards

Liz

Rödder²,

Gonçãlves

et al. 2022

Journal of Biogeography

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Aim Hyper‐arid sandy and rocky fields rank among the least biologically diverse habitats of the desert biome, yet knowledge of local biodiversity patterns is also extremely poor. In the Sahara Desert, palaeoclimate oscillations affected the extent of hyper‐arid habitats, but it is unclear how these dynamics determined the evolution and distribution of local specialists. Herein, we assessed cryptic diversity, diversification patterns and spatial connectivity within a Sahara‐widespread group of dryland‐adapted lizards. Location Sahara‐Sahel ecoregions. Taxon Acanthodactylus scutellatus species group. Methods Inter‐ and intraspecific phylogenetic structure, divergence times, spatial genetic patterns and cryptic diversity were assessed using nuclear and mitochondrial loci. The effects of topography and land cover on phylogeographic structure and diversity were tested with generalized linear models. Interspecific hybridization was evaluated using 11 microsatellites across the group's major sympatry zone, predicted based on ecological niche models. Results Species of Acanthodactylus scutellatus group exhibit Late Miocene origins, followed by extensive intraspecific divergence throughout the Pliocene. The northern Sahara worked as a major diversification hotspot, harbouring a patchwork of small‐ranged, divergent lineages. These lineages are parapatric or sympatric and present concordant nuclear and mitochondrial differentiation, suggesting species status. Genetic connectivity increases in southern latitudes, with wide‐ranging lineages spanning from the Red Sea to the Atlantic coast. Within these potential corridors, mountain outskirts and sand fields in the Sahara interior seemingly acted as origins for recent population expansions. Genetic diversity and connectivity are favoured by terrain roughness and soft‐sand cover respectively. Three species inhabit the Atlantic Sahara sympatry zone without evidence of gene flow. Main conclusions Overlooked species‐level diversity within a major specialist group of Sahara drylands exposes the recurrent knowledge shortfalls present in hyper‐arid desert environments. Humidity and sandy habitat shifts triggered potential successions of population isolation and re‐connectivity, which favoured cladogenesis in northern desert regions and population expansions across southern east–west corridors.

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“…To confirm this hypothesis, a provenance study should be conducted to analyze the origins of dust particles from various events e.g. using radiogenic isotopes (Barkley et al, 2022;Guinoiseau et al, 2022).…”

Section: Dust Event Characterizationmentioning

confidence: 99%

High-resolution sampling in the eastern tropical North Atlantic reveals episodic Saharan dust deposition: implications for the marine carbon sink

Matzenbacher,

Brummer,

Prins

et al. 2024

Front. Mar. Sci.

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In this study we present data collected between August 2017 and December 2018 from submarine sediment trap M1 located in the eastern tropical North Atlantic and determine lithogenic and biogenic fluxes, and grain-size distributions of aerosol dust. An unprecedented high sampling resolution of four days in combination with satellite imagery allowed the identification of thirteen major dust events of two types within the 468-day series. Seven dust events were classified as high-flux events identified by a deposition of >=25 mg m-2 d-1. The average dust deposition rate increased by 461.3% during these types of events. The remaining six events were characterized by a high composition of giant particles (>7.3 vol%). Seasonal variations of dust flux were recorded, with highest fluxes observed in spring at an average deposition rate of 14.8 mg m-2 d-1, and lowest fluxes in fall with an average rate of 8.6 mg m-2 d-1. The estimated total dust flux in the tropical North Atlantic was 4040.02 mg m-2 y-1. We suggest that most of the summer dust was likely transported over the sampling site at high altitudes while winter transport occurred closer to the sea surface, resulting in generally higher background fluxes. Grain-size distributions exhibited seasonal variations with increased occurrences of giant particles (>62.5 μm) in fall 2017 and spring, and less occurrences in winter and fall 2018. Grain-size sorting was high in spring and most variable in summer. Precipitation did not affect depositional fluxes or grain-size distributions of the aeolian dust significantly. Organic matter was deposited continuously at the sampling site with a deposition rate ranging from 14.4–862.25 mg m-2 d-1. Organic matter fluxes increased by 199.5% during high-flux dust events but decreased by 13.6% during anomalous grain-size events. Spring experienced the highest number of dust events (n=5). This unprecedented high-resolution dataset of dust deposition in marine sediment-traps enabled the distinction of dust events and their relation to organic matter flux. This suggests the possibility of a dust fertilization or mineral ballasting effect.

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Interannual Variability in the Source Location of North African Dust Transported to the Amazon

Cited by 13 publications

References 82 publications

Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas

Respirable Metals, Bacteria, and Fungi during a Saharan–Sahelian Dust Event in Houston, Texas

Overlooked species diversity in the hyper‐arid Sahara Desert unveiled by dryland‐adapted lizards

High-resolution sampling in the eastern tropical North Atlantic reveals episodic Saharan dust deposition: implications for the marine carbon sink

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