Viable Microorganisms on Fibers Collected within and beyond the Planetary Boundary Layer

Abstract

Fibers are found in all environments. However, the impact of their presence on ecosystems and human health is not yet well understood, especially in the case of the atmosphere. In this work, we presented evidence that fibers traveling through the atmosphere act as vectors to spread microorganisms. Here, we investigated the presence of viable microorganisms on fibers collected within and beyond the planetary boundary layer during flights of C-212 aircraft over Central Spain. In total, seven fibers, six of which transported viable microorganisms, were isolated in two flights. The viability of the microorganisms was determined by confocal microscopy by means of the fluorescent probes SYBR-Green to detect microorganisms and CTC redox dye to assess their cellular respiration activity. The fibers that transported viable microorganisms were spectroscopically analyzed by micro-FTIR and identified as wool-silk and cellulose-cotton. Taken together, the results demonstrated that fibers host viable microorganisms when traveling through the lower free troposphere.