Search Results (3)

Soil biodiversity is fundamental for ecosystems, ensuring many ecosystem functions, such as nutrient cycling, organic matter decomposition, soil formation, and organic carbon pool increase. Due to these roles, there is a need to study and completely understand how soil biodiversity is composed through different habitats. The aim of this study was to describe the edaphic soil community of the alpine environments belonging to the Gran Paradiso National Park, thus detecting if there are any correlation with environmental features. We studied soil fauna through environmental DNA metabarcoding. From eDNA metabarcoding, 18 families of arthropods were successfully detected, and their abundance expressed in terms of the relative frequency of sequences. Soil faunal communities of mixed coniferous forests were characterized by Isotomidae, Entomobriydae, Hypogastruridae, and Onychiuridae; while mixed deciduous forests were composed mostly by Isotomidae, Cicadidae, Culicidae, and Neelidae. Calcicolous and acidic grasslands also presented families that were not detected in forest habitats, in particular Scarabaeidae, Curculionidae, Brachyceridae, and had in general a more differentiated soil community. Results of the Canonical Component Analysis revealed that the main environmental features affecting soil community for forests were related to vegetation (mixed deciduous forests, tree basal area, tree biomass, Shannon index), soil (organic layers and organic carbon stock), and site (altitude); while for prairies, soil pH and slope were also significant in explaining soil community composition. This study provided a description of the soil fauna of alpine habitats and resulted in a description of community composition per habitat and the relation with the characteristic of vegetation, soil, and topographic features of the study area. Further studies are needed to clarify ecological roles and needs of these families and their role in ecosystem functioning. Full article

Deyeuxia purpurea, a low-altitude species, has been expanding upwards into alpine tundra, and this upward expansion is causing serious ecological consequences. However, few studies have been performed regarding its effects on soil faunal communities. We examine how the upward expansion of D. purpurea affects the abundance, richness, and diversity of soil mesofauna, and evaluate how different taxa of soil mesofauna respond to the upward expansion of D. purpurea in the alpine tundra of Changbai Mountains, northeast China. A total of 128 soil mesofaunal samples were collected from four treatments, namely high upward expansion (HU), medium upward expansion (MU), low upward expansion (LU), and native plant habitats (NP). The results revealed that the abundance of soil mesofauna was increased with the rise of D. purpurea upward expansion, and the taxonomic composition varied with the different levels of D. purpurea upward expansion in the alpine tundra of the Changbai Mountains. No unique taxa were collected in the native plant habitats, and the upward expansion of D. purpurea promoted the colonization of predatory invertebrates. Isotomidae and Gamasida responded positively to the herbaceous plant upward expansion, and thus they were considered to be a positive indicator of upward expansion. Hypogastruridae and Enchytraeidae responded relatively negatively, while Oribatida, Actinedida, and Pseudachorutidae had ambivalent responses to the upward expansion. Overall, the abundance of soil mesofauna can indicate the levels of the upward expansion of D. purpurea. Soil mesofaunal guild characteristics were altered by the upward expansion. The different taxa of soil mesofauna responded to herbaceous plants’ upward expansion to various degrees. Therefore, this study provide evidence supporting the fact that the abundance of soil mesofauna can indicate the levels of upward expansion of D. purpurea, but the responses of soil mesofauna to the upward expansion of D. purpurea differ among their taxa. Full article

Ice-binding proteins (IBPs) are found in many organisms, such as fish and hexapods, plants, and bacteria that need to cope with low temperatures. Ice nucleation and thermal hysteresis are two attributes of IBPs. While ice nucleation is promoted by large proteins, known as ice nucleating proteins, the smaller IBPs, referred to as antifreeze proteins (AFPs), inhibit the growth of ice crystals by up to several degrees below the melting point, resulting in a thermal hysteresis (TH) gap between melting and ice growth. Recently, we showed that the nucleation capacity of two types of IBPs corresponds to their size, in agreement with classical nucleation theory. Here, we expand this finding to additional IBPs that we isolated from snow fleas (the arthropod Collembola), collected in northern Israel. Chemical analyses using circular dichroism and Fourier-transform infrared spectroscopy data suggest that these IBPs have a similar structure to a previously reported snow flea antifreeze protein. Further experiments reveal that the ice-shell purified proteins have hyperactive antifreeze properties, as determined by nanoliter osmometry, and also exhibit low ice-nucleation activity in accordance with their size. Full article