Validation of Inexpensive Environmental DNA Air Samplers Under Field Conditions

Abstract

Environmental DNA (eDNA) has emerged as a powerful tool for biodiversity monitoring, yet its application in airborne systems is limited by challenges in DNA quality and quan tity. This study investigates whether low-volume sampling approaches can recover sufficient DNA for downstream molecular analysis and enable detection of arthropod taxa. Air was filtered using cost effective air samplers with low flow rates, and eDNA was processed using an optimized DNA extraction protocol designed to increase yield from low-biomass systems. DNA concentrations from airborne samples were significantly higher than laboratory blanks, demonstrating that low-volume air sampling can recover measurable DNA. However, large variability among samples indicates stochastic recovery that is likely driven by low DNA concentrations and heterogeneous DNA distribution in the air. Metabarcoding using an in vertebrate primer set amplified DNA in 32 of 85 airborne eDNA samples, with amplification probability being positively correlated to DNA concentration. Sanger sequencing confirmed the amplification of arthropod DNA, however over 50% of samples yielded sequences origi nating from fungal taxa, indicating strong non-target amplification. Laboratory blanks also produced arthropod sequences, indicating laboratory contamination is a significant concern. Attempts at Next Generation Sequencing failed, likely due to insufficient quality of DNA caused by low quantity and high fragmentation. Collectively these findings demonstrate that airborne eDNA collected via low-volume air samples has potential as a biomonitor ing tool, but is constrained by low-quality DNA, non-target amplification, and laboratory contamination. This study underscores a tradeoff between sampling scalability and molecu lar reliability, and highlights the need for improved protocols to distinguish true ecological signals from background noise.