Beta diversity—the variation among community compositions in a region—is a fundamental measure of biodiversity. Most classic measures have posited that beta diversity is maximized when each community has a distinct, nonoverlapping set of species. However, this assumption overlooks the ecological significance of species interactions and non-additivity in ecological systems, where the function and behavior of species depend on other species in a community. Here, we introduce a geometric approach to measure beta diversity as the hypervolume of the geometric embedding of a metacommunity. Besides considering compositional distinctiveness as in classic metrics, this geometric measure explicitly incorporates species associations and captures the idea that adding a unique, species-rich community to a metacommunity increases beta diversity. We show that our geometric measure is closely linked to and naturally extends previous information- and variation-based measures. Additionally, we provide a unifying geometric framework for widely adopted extensions of beta diversity. Applying our geometric measures to empirical data, we address two long-standing questions in beta diversity research—the latitudinal pattern of beta diversity and the effect of sampling effort—and present novel ecological insights that were previously obscured by the limitations of classic approaches. In sum, our geometric approach offers a new and complementary perspective on beta diversity, is immediately applicable to existing data, and holds promise for advancing our understanding of the complex relationships between species composition, ecosystem functioning, and stability.
Microplastics (MPs) are emerging contaminants known to have contaminated not only surface and groundwater but also drinking water treatment plants (DWTPs) and tap water. Little is known about the occurrence of MPs in DWTPs in Africa, particularly in developing countries like Nigeria. To address this knowledge gap, this study investigated the prevalence and estimated daily intake of MPs in raw water, DWTPs, and tap water in a semi-urban area in Ogun State, Nigeria. Using Rose Bengal staining and optical microscopy, MPs in water samples were identified and characterised using standard methods. The abundances of MPs were 16.13 ± 3.83 particles/L in raw water, 10.74 ± 3.76 particles/L in treated water, and 12.43 ± 3.92 particles/L in tap water. Most of the MPs found in the water samples were classified as fibres, followed by fragments, with a size of < 1 mm. This study showed that the drinking water treatment plant reduced microplastics from raw water by 40%, however, there was an increase in the abundance of MPs in tap water. Residents estimated daily consumption of MPs from tap water varied between 0.31 and 0.44 particles for adults and between 1.2 and 1.69 particles for children. This study addresses a critical gap in understanding microplastic pollution in the water distribution systems and DWTPs. The results also indicated that MPs were not effectively removed, requiring a more sophisticated treatment method to lower human exposure to MPs through drinking water from DWTPs.