Temperature dependences of European soil microbial communities – a climate gradient

University essay from Lunds universitet/Examensarbeten i biologi

Author: Eva Berglund; [2016]

Keywords: Biology and Life Sciences;

Abstract: How are microbial communities shaped by their climate? Significantly more carbon (C) is stored in the world’s soils than is present in the atmosphere. Although we hear a lot about increasing amount of carbon dioxide (CO2) in the atmosphere, mainly due to anthropogenic activity such as emissions from e.g. the car industry, we tend to forget about one of the crucial factors that can determine the planets response to climate change – the soils and its inhabitants! The stocks of carbon in soils results from the balance between inputs and outputs within the below-ground environment. Inputs are primarily dead plant litter and outputs are “leftovers” from decomposition of this material – mainly greenhouse gases. The decomposers of the soil either incorporate the carbon into their bodies or respire it out. Just like you, me and all living things. There is currently a debate about the importance of temperature on this decomposition processes. But first, who are they? They are really tiny organisms, mainly fungi and bacteria – hence they are often called microorganisms. Also, there is many of them and they are everywhere. We decided to investigate a fraction of them, covering a climate gradient all the way from the cold places of northern Europe, further trough the milder climate of southern Europe, ending up in the tropical climate of greenhouses in Lund Botanical Garden. One could imagine, that the communities of these soil microorganism separated over large distances would have adapted to the prevalent temperature conditions surrounding them. By measuring their activity, and correlate it to the mean annual temperatures of the different locations, our study found that: indeed they are. Furthermore, we can predict the magnitude of change in bacterial temperature dependence along a climate gradient. As our results also coincides with that of others, we are now able to estimate and predict the minimum temperature of bacterial growth for soils of a known temperature, with a greater certainty. Fitting in to a greater perspective, this also adds insightful information valuable for a better understanding when dealing with questions regarding climate impacts. Supervisor: Johannes Rousk Assistant supervisor: Johanna Birgander Bachelor's Degree Project 15 credits BIOK01 2016 Department of Biology, Lund University

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