Will fungi solve the carbon dilemma?

Environmental Biolog

Ecosystem coupling:A unifying framework to understand the functioning and recovery of ecosystems

Global change frequently disrupts the connections among species, as well as among species and their environment, before the most obvious impacts can be detected. Therefore, we need to develop a unified conceptual framework that allows us to predict early ecological impacts under changing environments. The concept of coupling, defined as the multiple ways in which the biotic and abiotic components of ecosystems are orderly connected across space and/or time, may provide such a framework. Here, we operationally define the coupling of ecosystems based on a combination of correlational matrices and a null modeling approach. Compared with null models, ecosystems can be (1) coupled; (2) decoupled; and (3) anticoupled. Given that more tightly coupled ecosystems displaying higher levels of internal order may be characterized by a more efficient capture, transfer, and storage of energy and matter (i.e., of functioning), understanding the links between coupling and functioning may help us to accelerate the transition to planetary-scale sustainability. This may be achieved by promoting self-organized order

Grazing by collembola controls fungal induced soil aggregation

Fungi affect soil aggregation and hence soil structure. Soil aggregation by saprotrophic fungi has been linked to various fungal traits but not tested during interactions with other organisms such as grazing soil fauna. Here we investigated how fungal identity and traits such as mycelial extension rate and biomass production affect aggregation across 49 fungal species isolated from sandy soils with different land uses. We tested each fungus and its effect on aggregation in the presence and absence of a grazer (Folsomia candida). We show that fungal species vary widely in their ability to aggregate soil, that the ability to aggregate soil was not phylogenetically conserved and the best trait predictor for aggregation was mycelial extension rate. Moreover, we show that the interactions between fungi and collembola affect the ability of fungi to aggregate soils. We conclude that identity of fungal species and their interaction with grazers affects soil aggregation and thus soil structure

Rhizosphere fungi actively assimilating plant-derived carbon in a grassland soil

Despite the advantages of the next generation sequencing (NGS) techniques, one of their caveats is that they do not differentiate between microbes that are actively participating in carbon cycling in the rhizosphere and microbes performing other functions in the soils. Here we combined DNA-SIP with NGS to investigate which rhizosphere fungi actively assimilate plant-derived carbon. We provided 13CO2 to plants in intact soil cores collected from a grassland and sampled the rhizosphere in a time series to follow the fate of carbon in the rhizosphere mycobiome. We detected a difference between active rhizosphere fungi using plant-derived carbon and the total mycobiota: 58% of fungal species were using fresh rhizodeposits, and an additional 22% of fungal species received carbon several weeks later while 20% were not involved in cycling of freshly photosynthesized carbon. We show that members of Ascomycota, Mucoromycota, and basidiomycete yeasts were first users of freshly photosynthesized carbon, while fungi not using recently fixed carbon consisted mainly of mycelial (non-yeast) Basidiomycota. We conclude that a majority of fungi inhabiting the rhizosphere in this grassland ecosystem are actively using plant derived carbon either directly or via food-web interactions