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Temperature adaptation of bacterial soil communities

Hopf, Charlotte (2023) MOBN02 20222
Degree Projects in Molecular Biology
Popular Abstract
HOW WILL SOIL BACTERIA REACT TO RISING TEMPERATURES?

A significant amount of carbon is stored in soil, where microbes play a crucial role in determining how much carbon gets fixed and how much is released as CO2 into the atmosphere. This depends on the balance between microbial growth, which fixes carbon in soils, and in contrast on respiration which leads to the release of CO2. Approximately 50% of the yearly carbon release into the terrestrial biosphere comes from microbial respiration. Given the large quantities involved, even small changes in these processes could have significant impacts on atmospheric CO2 concentrations.

Microbial activity, including growth and respiration, is influenced by climate change. Typically, when... (More)
HOW WILL SOIL BACTERIA REACT TO RISING TEMPERATURES?

A significant amount of carbon is stored in soil, where microbes play a crucial role in determining how much carbon gets fixed and how much is released as CO2 into the atmosphere. This depends on the balance between microbial growth, which fixes carbon in soils, and in contrast on respiration which leads to the release of CO2. Approximately 50% of the yearly carbon release into the terrestrial biosphere comes from microbial respiration. Given the large quantities involved, even small changes in these processes could have significant impacts on atmospheric CO2 concentrations.

Microbial activity, including growth and respiration, is influenced by climate change. Typically, when temperatures rise, their activity rates increase until the optimum temperature (Topt), beyond which they decrease. Below a minimum temperature (Tmin) and above maximum temperature (Tmax) the microbial activity is zero (Fig. 1). Additionally, when microbes are exposed to certain temperatures, they adapt, causing a shift in the microbial temperature dependence curve. However, there are still many uncertainties surrounding these temperature adaptations. As global temperatures rise due to climate change, understanding how microbes will respond to these changes becomes crucial. Such knowledge will enable us to predict microbial responses to warming accurately, contributing to broader climate change mitigation efforts.
To investigate the different timescales of temperature adaptation and the influence of prior temperatures on this process, we conducted a field and laboratory experiment. We compared soil samples from both Arctic and temperate environments, as well as heat-treated field samples from the temperate environment. Over a nine-week period, we examined the temperature adaptation of bacterial growth in a laboratory setting. Previous lab experiments did not capture cold adaptation, which was hypothesized to be due to slow growth rates in cold temperatures. To speed up the adaptation process and possibly observe such cold adaptation, we subjected the bacterial community to weekly freeze-thaw cycles, which did not show the expected results. Nevertheless, we gained valuable insights into the timescales of warm-adaptation, which varied based on the prior temperature. Samples from the temperate environment adapted rapidly to extremely high temperatures, which showed in right-shifted bacterial temperature dependence curves. Communities from the Arctic, originating from much lower temperatures, showed a slower adaptation.

These findings provide important insights into how microbial communities respond to temperature changes and emphasize the significance of their environment in shaping their adaptations.

Master’s Degree Project in Microbiology, Molecular Biology 45 credits 2022-2023 Department of Biology, Lund University
Supervisors: Johannes Rousk, Carla Cruz Peredes, Dániel Tájmel
Microbial ecology, Department of Biology, Lund (Less)
Please use this url to cite or link to this publication:
author
Hopf, Charlotte
supervisor
organization
course
MOBN02 20222
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
9140790
date added to LUP
2023-11-02 14:49:32
date last changed
2023-11-02 14:49:32
@misc{9140790,
  author       = {{Hopf, Charlotte}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Temperature adaptation of bacterial soil communities}},
  year         = {{2023}},
}