Soil Biotic Complexity Shapes Grassland Bacterial Communities and Ecosystem Functioning
Universiteit Antwerpen
2024
Genomineerde shortlist Scriptieprijs
Soils are everywhere and they are teeming with life. They contain over 59% of all biodiversity and these different species are in close contact with each other. Soil organisms interact with such a vast array of other soil organisms that they construct an intricate soil community network, which is still poorly understood. However, global change is pushing down on these smaller life forms and, by extent, threatening the world as we know it. The loss in soil biodiversity is tangible in the functional network and stunts the performance of entire ecosystems.
This thesis will point our gaze downwards, literally. We will explore the intricate soil network, comprised of life such as microscopic insects, worm-like organisms, fungi and bacteria. While largely invisible, the cooperation of these organisms keeps both the natural world and our civilisation running, as they deliver valuable ecosystem functions which shape our aboveground worlds. Bacteria are an essential cornerstone in soil networks. For instance, they are crucial in the decomposition process, in which they recycle organic matter and thus revitalise the ecosystem. This was our reason to further look into how Bacteria are impacted by the loss of whole groups from the soil network.
This research has found that subsequentially losing more and more different organism groups results in bacterial communities which differ significantly from each other. As their composition changes, the benefits they provide to the ecosystem change as well. We showed that the ability of bacteria to recycle nutrients is drastically impeded as the soil networks are degrading. This will in turn cause further decline in biodiversity as certain species will be unable to sustain their nutritional needs
Plant productivity was affected as well. While grasses seemed to be more resilient, herbs decreased in their performance, which could ultimately have important consequences for the ecosystems, such as a lower abundance of flowers for pollinators.
This study underlines the efficiency of a diverse soil system. Due to the disruption in the trophic and decomposition networks, the functioning of the overall soil network declines in its efficiency. This is alarming considering these belowground communities are the foundation of our aboveground world.
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