Soils host the vast majority of life on Earth including microorganisms and animals, and supporting all terrestrial vegetation. While soil organisms are pivotal for ecosystem functioning, the assemblages of different biota from a taxonomic and functional perspective, as well as how these different organisms interact, remains poorly known. We provide a brief overview of the taxonomic and functional diversity of all major groups of soil biota across different scales and organism sizes, ranging from viruses to prokaryotes and eukaryotes.
Anthropogenic climate change is altering the functioning of terrestrial ecosystems. Agricultural systems are particularly vulnerable to climate change as they are frequently disturbed by intensified management practices. This also threatens belowground organisms that are responsible for providing crucial ecosystem functions and services, such as nutrient cycling and plant disease suppression. Amongst these organisms, earthworms are of particular importance as they can modulate the effects of climate change on soil organisms by modifying the biotic and abiotic soil conditions.
Microplastics (MP) provide a unique and extensive surface for microbial colonization in aquatic ecosystems. The formation of microorganism-microplastic complexes, such as biofilms, maximizes the degradation of organic matter and horizontal gene transfer. In this context, MP affect the structure and function of microbial communities, which in turn render the physical and chemical fate of MP. This new paradigm generates challenges for microbiology, ecology, and ecotoxicology.
Plastics are an integral but largely inconspicuous part of human daily routines. Associated with a high production and single use nature of several products, small plastic particles became ubiquitous. Due to processes like water currents and winds, plastics may occur far from their place of origin and affect biota at different environmental compartments. In the environment plastics can degrade into increasingly smaller particles, reaching a nanometer size which increases their potential to be incorporated by organisms.
The presence of plastic debris in the ocean is increasing and several effects in the marine environment have been reported. A great number of studies have demonstrated that microplastics (MPs) adsorb organic compounds concentrating them several orders of magnitude than the levels found in their surrounding environment, therefore they could be potential vectors of these contaminants to biota. However, a consensus on MPs as vectors of persistent organic pollutants (POPs) has not been reached since are opposing views among different researchers on this topic.
This study assessed the carbon (C) budget and the C stocks in major compartments of the soil food web (bacteria, fungi, protists, nematodes, meso- and macrofauna) in an arable field with/without litter addition. The C stocks in the food web were more than three times higher in topsoil (0–10 cm) compared to subsoil (>40 cm). Microorganisms contained over 95% of food web C, with similar contributions of bacteria and fungi in topsoil. Litter addition did not alter C pools of soil biota after one growing season, except for the increase of fungi and fungal feeding nematodes in the topsoil.
Non-vascular plants such as mosses, lichens and especially microalgae are widespread in terrestrial ecosystems, but their contribution in the nutrient cycling and energy budget of soil food webs is generally neglected. Despite a relatively low total biomass, soil microalgae can be very productive and contribute to the diet of many soil decomposers such as Collembola. Using 15N/14N ratios we showed that phycophagy is of particular importance for Collembola in extreme habitats like rock surfaces, or seasonally during the wintertime.
