Legacy effects of temperature alterations on microbial resistance and resilience to drying and rewetting
(2023) In Student thesis series INES NGEM01 20231Dept of Physical Geography and Ecosystem Science
- Abstract
- With warming in soils due to climate change, a series of secondary factors arise, which have multifaceted effects on soil microbial communities. Of these, alterations to soil moisture are among the most crucial to understanding how microbial functions will change in the face of climate change. As living organisms, microbes must adapt to their environment, and their adaptations are reflected in their response to contemporary events. How they respond can determine the fate of soil organic matter and have relevant feedback to climate systems. In this thesis, I address how the legacy effects of a soil microbial community affect its response to a drying and rewetting event in terms of resilience and resistance, as well as how these strategies... (More)
- With warming in soils due to climate change, a series of secondary factors arise, which have multifaceted effects on soil microbial communities. Of these, alterations to soil moisture are among the most crucial to understanding how microbial functions will change in the face of climate change. As living organisms, microbes must adapt to their environment, and their adaptations are reflected in their response to contemporary events. How they respond can determine the fate of soil organic matter and have relevant feedback to climate systems. In this thesis, I address how the legacy effects of a soil microbial community affect its response to a drying and rewetting event in terms of resilience and resistance, as well as how these strategies can affect carbon dynamics in subarctic ecosystems. I achieved this by taking soil samples from study sites that have undergone two-year warming in Abisko, Sweden. I then subjected them to a drying and rewetting cycle, assessing the samples as they dried down and subsequently responded to being rewet. During this time, I measured bacterial and fungal growth via stable isotope probing as well as respiration via gas chromatography. I found that while moisture was affected, microbial resistance was unaffected by warming treatments. However, resilience was affected by warming treatments. Responses also differed primarily based on NDVI, possibly indicating the importance of plant inputs of carbon to the microbial response. Possible conceptual frameworks are then used to explain the observations, notably the YAS framework. Implications for carbon budgeting and models are inferred from these findings. I conclude that interactions between microbes and moisture and plant inputs impact microbial response to moisture stress in warming experiments and that future experiments may want to examine the vegetation relationship with more focus. (Less)
- Popular Abstract
- Alterations to the carbon cycle have caused climate change to warm the planet. The arctic is warming at nearly triple the rate as the rest of the globe. Most of the world’s biologically relevant carbon is below ground in the arctic and subarctic. This is a result of the cold climate reducing decomposition below annual production, for policy to adapt to upcoming climate changes which may affect the stability of this carbon. In this study, I examined how temperature alterations to soil microbial communities alter their response to moisture alterations such as drought and drying then rewetting. I used warmed sites near the Abisko research station in the subarctic birch forest that had five treatments of warming. The treatments consisted of a... (More)
- Alterations to the carbon cycle have caused climate change to warm the planet. The arctic is warming at nearly triple the rate as the rest of the globe. Most of the world’s biologically relevant carbon is below ground in the arctic and subarctic. This is a result of the cold climate reducing decomposition below annual production, for policy to adapt to upcoming climate changes which may affect the stability of this carbon. In this study, I examined how temperature alterations to soil microbial communities alter their response to moisture alterations such as drought and drying then rewetting. I used warmed sites near the Abisko research station in the subarctic birch forest that had five treatments of warming. The treatments consisted of a control plot, a summer warming plot, a winter warming plot, a chronic (year-round) warming plot and an extreme warming plot. I sampled soil and took field measurements of these treatments. I then dried the soil down, and then rewet it. During these alterations, I used isotopic methods to measure the growth of microbes. I also measured their respiration during this time. I found that microbial communities did not stay active during the drought period and that treatments had no effect on this. However, microbial communities that had a higher amount of photosynthesis had a more robust response, while microbial communities that had experienced dryer conditions had a more efficient response. I associate this response with the microbes adapting to both the stress of the moisture deficit as well as potential stress of carbon availability. I theorized that this might be because of microbes have to shift their activities in plots without plants. Plants provide carbon which microbes can use as an energy source and without it, there is a possibility that the ability to respond to stress may have been impaired. The carbon dynamics described in this study could be used in models and carbon budgeting for future warming. Additionally, understanding the ecology of soil microbes on a functional level helps to build a knowledge base for what governs these interactions and moves closer to deriving a mechanism for such responses (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9131047
- author
- Harris, Franklin Lee LU
- supervisor
- organization
- course
- NGEM01 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- microbial ecology, soil, carbon dynamics, high latitudes, climate change, moisture stress, isotopes, respiration, trait based ecology, soil microbes, Environmental Changes in High Latitudes (EnCHIL)
- publication/series
- Student thesis series INES
- report number
- 620
- funder
- The Leifur Eiríksson Foundation
- language
- English
- additional info
- Thesis approved in partial fulfilment of a double Nordic Master MSc degree in environmental changes at higher latitudes (EnCHiL), from Lund University and the Agricultural University of Iceland.
- id
- 9131047
- date added to LUP
- 2023-06-28 22:26:26
- date last changed
- 2023-06-28 22:26:26
@misc{9131047,
abstract = {{With warming in soils due to climate change, a series of secondary factors arise, which have multifaceted effects on soil microbial communities. Of these, alterations to soil moisture are among the most crucial to understanding how microbial functions will change in the face of climate change. As living organisms, microbes must adapt to their environment, and their adaptations are reflected in their response to contemporary events. How they respond can determine the fate of soil organic matter and have relevant feedback to climate systems. In this thesis, I address how the legacy effects of a soil microbial community affect its response to a drying and rewetting event in terms of resilience and resistance, as well as how these strategies can affect carbon dynamics in subarctic ecosystems. I achieved this by taking soil samples from study sites that have undergone two-year warming in Abisko, Sweden. I then subjected them to a drying and rewetting cycle, assessing the samples as they dried down and subsequently responded to being rewet. During this time, I measured bacterial and fungal growth via stable isotope probing as well as respiration via gas chromatography. I found that while moisture was affected, microbial resistance was unaffected by warming treatments. However, resilience was affected by warming treatments. Responses also differed primarily based on NDVI, possibly indicating the importance of plant inputs of carbon to the microbial response. Possible conceptual frameworks are then used to explain the observations, notably the YAS framework. Implications for carbon budgeting and models are inferred from these findings. I conclude that interactions between microbes and moisture and plant inputs impact microbial response to moisture stress in warming experiments and that future experiments may want to examine the vegetation relationship with more focus.}},
author = {{Harris, Franklin Lee}},
language = {{eng}},
note = {{Student Paper}},
series = {{Student thesis series INES}},
title = {{Legacy effects of temperature alterations on microbial resistance and resilience to drying and rewetting}},
year = {{2023}},
}