Temperature adaptation of soil bacterial communities across the Arctic
Microorganisms that inhabit soils across the Arctic are typically well adapted to low temperatures and are highly responsive to temperature increases. A change in temperature adaptation of microbial communities might affect how fast they will decompose soil organic matter in a warmed Arctic. Current...
| Summary: | Microorganisms that inhabit soils across the Arctic are typically well adapted to low temperatures and are highly responsive to temperature increases. A change in temperature adaptation of microbial communities might affect how fast they will decompose soil organic matter in a warmed Arctic. Currently, the potential change in temperature adaptation of soil bacterial communities is under scientific debate, due to contrasting observations made in field and laboratory settings. Therefore, the overall aim of this thesis was to evaluate the current temperature adaption of soil bacterial communities in the Arctic and to investigate whether the temperature adaptation of arctic soil bacterial communities shifts when exposed to warmed conditions. In Chapter 2, the optimal growth temperature of bacterial communities increased when comparing samples from the colder sites to warmer sites. I observed that one of the most important factors for their temperature adaptation was the mean maximum soil temperature. I concluded from this study that increasing temperatures – especially summer temperatures – will likely alter the temperature adaptation of bacterial communities in arctic soils. To confirm this hypothesis, I conducted an incubation study with 8 soils collected from the (sub-) Arctic and exposed them to different temperatures, ranging between 0 and 30°C. When the soils were incubated, the bacterial communities altered their temperature adaptation depending on the incubation temperature. In the third chapter, I also found that the induced change in temperature adaptation of soil bacterial communities was accompanied by a change in the overall composition of the bacterial community. Therefore, I hypothesized that the individual response of bacterial species to soil warming might reflect the temperature adaptation. Thus, the abundance of particular bacterial species in a soil sample could be potentially used for estimating the temperature adaptation of soil bacterial communities. In chapter 4, I evaluated the use of ... |
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