Effects of soil temperature on Sphagnum moss litter quality and decomposition in a subarctic environment
(2023) In Student thesis series INES NGEM01 20231Dept of Physical Geography and Ecosystem Science
- Abstract
- High latitude peatlands play a significant role in global soil carbon budgets, attributed to the slow decomposition rate of Sphagnum mosses that facilitates carbon sequestration through the build-up of peat. As climate change is predicted to increase soil temperatures and decomposition rates of organic matter, studying environmental and intraspecific mechanisms that controls decay resistance of Sphagnum mosses is central to understand potential shifts in peatland carbon storage. In this study, I show how soil temperature affects litter quality and decomposition rates of two Sphagnum species: S. papillosum and S. subnitens. I established a reciprocal litter bag experiment over a thermal gradient in Iceland to measure mass loss (%) of the... (More)
- High latitude peatlands play a significant role in global soil carbon budgets, attributed to the slow decomposition rate of Sphagnum mosses that facilitates carbon sequestration through the build-up of peat. As climate change is predicted to increase soil temperatures and decomposition rates of organic matter, studying environmental and intraspecific mechanisms that controls decay resistance of Sphagnum mosses is central to understand potential shifts in peatland carbon storage. In this study, I show how soil temperature affects litter quality and decomposition rates of two Sphagnum species: S. papillosum and S. subnitens. I established a reciprocal litter bag experiment over a thermal gradient in Iceland to measure mass loss (%) of the Sphagnum moss litters over a 4-month period and used Diffused Reflectance Infrared Transform Spectroscopy (DRIFTS) to analyse the organic chemical structure of the fresh and decomposed litters. My results showed that Sphagnum papillosum and S. subnitens have different rates of decomposition under different soil temperatures which relates to intra- and inter-specific variations in organic chemical structures. Sphagnum papillosum decomposed significantly faster in warmer soil conditions compared to colder soil conditions. In contrast, Sphagnum subnitens did not decompose significantly faster in the warmer soil conditions. There was a significant difference in the organic chemical structure between the hot-originating and cold-originating litter of Sphagnum subnitens, which was not seen for Sphagnum papillosum. These results suggest that Sphagnum papillosum will decompose faster under warmer soil temperatures whereas Sphagnum subnitens can resist decay due to metabolome plasticity. These findings demonstrate that there are species-specific adaptations to changing environmental conditions that should be considered in climate models. (Less)
- Popular Abstract
- High-latitude peatlands play a significant role in the global carbon budget. They can store the equivalent of one-third of the world's soil carbon pool. This occurs because organic matter decomposes very slowly and results in carbon being stored in the ground as peat, instead of being released to the atmosphere. Sphagnum is a genus of moss that is fundamental to peatlands and the build-up of peat because they create wet, anoxic, and acidic conditions, and have very decay resistant litter. With rising global temperatures from climate change, there has been growing concern that the break-down of organic matter in peatlands will increase and cause peatlands to release more carbon instead of storing it, contributing to the positive feedback of... (More)
- High-latitude peatlands play a significant role in the global carbon budget. They can store the equivalent of one-third of the world's soil carbon pool. This occurs because organic matter decomposes very slowly and results in carbon being stored in the ground as peat, instead of being released to the atmosphere. Sphagnum is a genus of moss that is fundamental to peatlands and the build-up of peat because they create wet, anoxic, and acidic conditions, and have very decay resistant litter. With rising global temperatures from climate change, there has been growing concern that the break-down of organic matter in peatlands will increase and cause peatlands to release more carbon instead of storing it, contributing to the positive feedback of climate change. The aim of this research was to understand which mechanisms controls the breakdown of Sphagnum mosses, i.e., are environmental factors such as soil temperature more important than structural properties of the species itself, or vice versa? To test this, I studied the decomposition of two Sphagnum species along a thermal gradient in Iceland for four months using a litterbag technique. I also studied the organic chemical structures of the same species using infrared spectroscopy. My results showed that different species of Sphagnum mosses decompose at different rates – some decompose very fast with warmer soil temperatures, whereas others do not. I also found that certain species can structurally adapt to warm soil environments which is why they are more resistant to decomposition under warmer soil conditions. These findings are important for understanding how climate change is affecting northern ecosystems as it shows that not all species of Sphagnum mosses respond to warmer environments in the same way. This could imply that some species will be better suited to warmer environments and continue the build-up of peat, whereas other species will decompose significantly faster in a warmer environment and release more carbon. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9132866
- author
- Gibson, Sahra LU
- supervisor
- organization
- course
- NGEM01 20231
- year
- 2023
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Physical geography and ecosystem analysis, Sphagnum moss, peatlands, decomposition rates, reciprocal litterbag, litter organic chemical structures, soil warming, Environmental Changes at Higher Latitudes (EnCHiL)
- publication/series
- Student thesis series INES
- report number
- 623
- language
- English
- id
- 9132866
- date added to LUP
- 2023-07-11 13:08:01
- date last changed
- 2023-07-11 13:08:01
@misc{9132866,
abstract = {{High latitude peatlands play a significant role in global soil carbon budgets, attributed to the slow decomposition rate of Sphagnum mosses that facilitates carbon sequestration through the build-up of peat. As climate change is predicted to increase soil temperatures and decomposition rates of organic matter, studying environmental and intraspecific mechanisms that controls decay resistance of Sphagnum mosses is central to understand potential shifts in peatland carbon storage. In this study, I show how soil temperature affects litter quality and decomposition rates of two Sphagnum species: S. papillosum and S. subnitens. I established a reciprocal litter bag experiment over a thermal gradient in Iceland to measure mass loss (%) of the Sphagnum moss litters over a 4-month period and used Diffused Reflectance Infrared Transform Spectroscopy (DRIFTS) to analyse the organic chemical structure of the fresh and decomposed litters. My results showed that Sphagnum papillosum and S. subnitens have different rates of decomposition under different soil temperatures which relates to intra- and inter-specific variations in organic chemical structures. Sphagnum papillosum decomposed significantly faster in warmer soil conditions compared to colder soil conditions. In contrast, Sphagnum subnitens did not decompose significantly faster in the warmer soil conditions. There was a significant difference in the organic chemical structure between the hot-originating and cold-originating litter of Sphagnum subnitens, which was not seen for Sphagnum papillosum. These results suggest that Sphagnum papillosum will decompose faster under warmer soil temperatures whereas Sphagnum subnitens can resist decay due to metabolome plasticity. These findings demonstrate that there are species-specific adaptations to changing environmental conditions that should be considered in climate models.}},
author = {{Gibson, Sahra}},
language = {{eng}},
note = {{Student Paper}},
series = {{Student thesis series INES}},
title = {{Effects of soil temperature on Sphagnum moss litter quality and decomposition in a subarctic environment}},
year = {{2023}},
}