Metagenomic investigation of African dust events in the Caribbean

Abstract

African dust from the Sahara and Sahel regions of Northern Africa is blown intercontinental distances and is the highest portion of atmospheric dust generated each year. During the Northern Hemisphere summer months (boreal summer), these dust events travel into the Caribbean and southern United States. While viability assays, microscopy and bacterial amplicon analyses have shown that dust-associated microbes may be diverse, the specific microbial taxa that are transported intercontinental distances with these dust events remain poorly characterized. To provide new insights into these issues, five metagenomes of Saharan dust events occurring in the Caribbean, collected in the summer months of 2002 and 2008, were analyzed. The data revealed that similar microbial composition existed between three out of the five of the distinct dust events and that fungi were a prominent feature of the metagenomes compared to other environmental samples. These results have implications for better understanding of microbial transport through the atmosphere and may implicate that the dust-associated microbial load transiting the Atlantic with Saharan dust is similar from year to year.

Assessing the efficacy of eDNA metabarcoding for measuring microbial biodiversity within forest ecosystems

“…4, 5). Our findings complement and lend further support for the promise of using eDNA metabarcoding as a tool for measuring and monitoring biodiversity [99][100][101][102] . While our prediction that throughfall samples would contain more diverse taxa than rainwater samples was supported, we also were interested in investigating how diversity might differ between throughfall and rainwater treatments (alpha diversity), among sampling locations (beta diversity), and the amount of within-treatment variation.…”

“…This phenomenon, driven by multiple factors including topography, seasonal patterns in global weather and prevailing winds, all of which are influenced by climate change, are known to transport significant amounts of mineral and trace nutrient inputs to the Amazon rainforest in South America 107,108 , and in general, hold important implications for nutrient inputs into forests 109 . Given the overwhelming support of the bioprecipitation hypothesis 70,[110][111][112] , it is likely that sampling Saharan dust, for example, using the eDNA metabarcoding approach set forth here, would yield a treasure trove of microbial community data, and would build upon findings from previous studies 101,113 to provide further insight into global-sale macroecological dynamics of interconnected yet geographically disparate biomes. Our study supports the hypothesis directly through our detection of Pseudomonas sp.…”

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

“…Nucleic acids were extracted from filters using commonly accepted protocols via bead-beating and purification and centrifugal filtration with modifications. ,,,, Following quality control measures, sequence reads were organized into operational taxonomic units (OTUs) at a threshold of 97% similarity. OTU is an operational definition of a classification unit (genus, species, grouping, etc.)…”

Dust from the Sahara to the American Continent: Health impacts

“…Some genera of bacteria and most fungi can form spores, a dormant state that is resistant to desiccation, heat, and radiation. 51 Sánchez de la Campa et al 46 found low microbial biodiversity associated with African dust over southern Spain. But microbes cultured on solid and liquid medium suggested that the bacteria transported were alive or presented as spores that could germinate under favorable conditions.…”