Detheridge, A. P. | bioRxiv Science

bioRxiv2026

AberTrap: an open-source, lightweight, programmable sampler of airborne biological particles

1. Context. Capturing and identifying airborne biological matter (bioaerosols) enables detailed characterisation of ecological communities, but the cost and weight of existing commercially available active air samplers limits the deployment of multiple devices needed to realise this potential. 2. Method. We present the AberTrap, a lightweight (~50g), open-source (CC-BY-SA), programmable rotating-arm bioaerosol sampler that can be self-built from common laboratory components and makerspace equipment at low cost (ca {pound}20 per unit, exc. power supply). To characterise the device's performance, we first explored the influence of rotational speed and paddle design on aerosol capture under controlled conditions, using fluorescein and a range of biological aerosols (4.5-33 m). To demonstrate its utility for ecological applications, we then validated field performance in a species-rich broadleaf woodland (England, UK), deploying eight samplers over five days and identifying captured fungal aerosols by ITS2 metabarcoding. 3. Key results. Modifying paddle design allowed us to influence particle selection and capture efficiency. Slotted paddles captured significantly more aerosols than plain paddles despite sampling less air, which we traced to the concentration of aerosols at the paddle leading edges. This effect was most pronounced for the smallest particles and outweighs the influence of rotational speed. In the field, 20 daily samples (four samplers over five days) detected 2,431 fungal taxa, 78.9% of the Chao2-estimated total fungal richness. A single sampler captured only 59% of this richness. Continuous 5-day sampling recovered 78% of the taxa detected by daily sampling, indicating only modest paddle saturation over this period. Our time segregated design allowed us to infer dispersal dynamics; 35% of taxa were recorded only on one day, and 19% recorded across all five days. Overall, replicate AberTraps provided high sampling completeness. 4. Implications. The AberTrap provides a low-cost, lightweight and programmable alternative to commercial rotating-arm samplers, enabling levels of spatial and temporal replication impractical with existing devices. Low cost and portability facilitate deployment in remote or resource-limited contexts. Its open-source, adaptable design allows the device to be tailored for applications in biodiversity assessment, pathogen surveillance and ecological monitoring.

ecology↗

bioRxiv2020

Soil stabilisation for DNA metabarcoding of plants and fungi. Implications for sampling at remote locations or via third-parties

Storage of soil samples prior to metagenomic analysis presents a problem. If field sites are remote or if samples are collected by third parties, transport to analytical laboratories may take several days or even weeks. The bulk of such samples and requirement for later homogenisation precludes the convenient use of a stabilisation buffer, so samples are usually cooled or frozen during transit. There has been limited testing of the most appropriate storage methods for later study of soil organisms by eDNA approaches. Here we tested a range of storage methods on two contrasting soils, comparing these methods to the control of freezing at -80{degrees}C followed by freeze-drying. To our knowledge this is the first study to examine the effect of storage conditions on eukaryote DNA in soil, including both viable organisms (fungi) and DNA contained within dying/dead tissues (plants). For fungi, the best storage regimes (closest to the control) were storage a 4{degrees}C (for up to 14 d) or active air-drying at room temperature. The worst treatments involved initial freezing followed by thawing which led to significant later spoilage. The key spoilage organisms were identified as Metarhizium carneum and Mortierella spp., with a general increase in saprotrophic fungi and reduced abundances of mycorrhizal/biotrophic fungi. Plant data showed a similar pattern but with greater variability in community structure especially in the freeze-thaw treatments, probably due to stochastic variation in substrates for fungal decomposition, algal proliferation and some seed germination. In the absence of freeze drying facilities, samples should be shipped refrigerated but not frozen if there is any risk of thawing.

ecology↗