The effect of dust storms on the concentration and content of fungi in the atmosphere of Haifa, Israel

Dust storms originated primarily in the Sahara Desert severely affected the East Mediterranean mostly during winter and spring seasons. The main goal of our study addressed the qualitative and quantitative aspects of dust-associated culturable fungal communities sampled during dust events 2004-2005 in Haifa, Israel, and their comparison with the communities sampled during the adjacent clear days. The effect of particulate matter concentrations and elemental composition of the atmospheric particles on fungal communities was also estimated. Airborne fungi were collected with the Six Stage Andersen Viable Impactor. Their taxonomic identification was based mainly on morphological characteristics; one repeatedly isolated type of nonsporulated colonies was identified employing the polymerase chain reaction (PCR). During six dust events and the adjacent clear days, 98 species were collected - 79 and 32 species in dusty and clear days, respectively. The dust-associated fungal communities were significantly richer than the communities found on clear days (Wilcoxon signed-rank test, p = 0.03). Remarkable increases in concentration of airborne fungi during the dust events compared to the adjacent clear days have also been revealed. The following species were most frequently and abundantly isolated: Alternaria alternata, Aspergillus niger, Cladosporium cladosporioides, Penicillium glabrum, P. chrysogenum, Phlebia sp. (the basidiomycete species identified by PCR), Ceriporia metamorphosa (>70% of samplings); A. versicolor, C. sphaerospermum, P. aurantiogriseum, P. griseoroseum, P. purpurogenum, and Pleospora tarda (>40% of samplings). The Canonical correspondence analysis showed that the dominant environmental factors influencing the distribution of these species were a concentration of fine atmospheric particles followed by the concentration of geological elements and coarse particles. On a whole, the study revealed distinct pattern of distribution for fungi in the atmosphere of Haifa strongly influenced by Saharan dust storms.