The Fate of Methanotrophically Fixed Carbon in Terrestrial Environments
Lead Research Organisation:
University of Bristol
Department Name: Chemistry
Abstract
The major cause of climate change is the atmospheric reintroduction via fossil fuel burning of large amounts of carbon that has been buried underground for millions of years. Once back in the atmosphere, the carbon-containing compounds absorb infrared radiation, which contributes to global warming. An effective way to limit the effects of global warming is through the removal of carbon containing compounds, such as carbon dioxide (CO2) and methane (CH4) from the atmosphere. The removal of atmospheric carbon and its storage in terrestrial environments, such as soils, is known as carbon sequestration. There are many natural processes that sequester carbon including the removal of atmospheric CO2 by terrestrial vegetation and marine organisms. Carbon from methane can also be sequestered in a similar way to carbon from CO2. Methanotrophs are bacteria that can utilise methane as their only source of carbon and are the major terrestrial methane sink. Methanotrophic bacteria remove a large proportion of methane formed in terrestrial environments and prevent it from reaching the atmosphere. In these circumstances they form a vital barrier that prevents the release of methane from natural wetlands, rice paddies, marine sediments and landfill sites. Whilst the amount of methane oxidised by methanotrophs in soils has been widely studied little is known about the fate of carbon from methane in soils and how much of this carbon is sequestered. To work out what happens to the carbon following methane oxidation in soils we are going to apply CH4 containing a tracer (13C-labelled methane) to a range of different soils. We will then track the fate of the label in the soil, to calculate what proportion of the carbon from CH4 is retained in the soil. We can also link the 13C-labelled CH4 to other soil microorganisms that utilise the carbon from methane as a source of food, and build up a picture of the wider soil microbial food web. Three different soil environments are going to be studied in this work. The initial development work will study a landfill cover soil and focus on establishing a range of new analytical techniques. The soil that overlays a landfill site contains extremely high concentrations of methane because as the organic waste in the landfill site degrades, it releases large amounts of methane. The methane permeates out to the atmosphere through the soil that covers the site. It is well known that bacteria in the landfill cover soils oxidise a large proportion of this methane but the ultimate fate of this carbon they consume is unknown. The fate of methane carbon in natural wetlands will also be studied. Natural wetlands include environments such as peat bogs, fens, salt marshes and tropical swamps. Natural wetlands have organic rich soils that release methane in a similar way to landfill sites when the soil organic matter degrades. We are going to study the fate of carbon from this methane following consumption by methanotrophic bacteria in the soil. The final type of soils that will be used to assess the fate of carbon from methane in soils are a range of soil chronosequences. A soil chronosequence is a related set of soils that formed under similar conditions of vegetation, topography and climate. The length of time over which the soils have developed is the only difference between the soils in the chronosequence. This will allow us to assess the relationship between soil development and the soil processes involved in carbon sequestration. Overall, the research will add a new dimension our understanding of the fate of carbon from one of the major green house gases as it is utilised and dispersed by the soil microbial community.
Organisations
Publications
Evershed R
(2017)
Microbial Biomass - A Paradigm Shift in Terrestrial Biogeochemistry
Maxfield PJ
(2012)
Stable isotope switching (SIS): a new stable isotope probing (SIP) approach to determine carbon flow in the soil food web and dynamics in organic matter pools.
in Rapid communications in mass spectrometry : RCM
Maxfield P
(2011)
Impact of land management practices on high-affinity methanotrophic bacterial populations: evidence from long-term sites at Rothamsted
in European Journal of Soil Science
Maxfield P
(2010)
Stable Isotope Probing and Related Technologies
Maxfield PJ
(2009)
Substantial high-affinity methanotroph populations in Andisols effect high rates of atmospheric methane oxidation.
in Environmental microbiology reports
Description | We have shown for the first time using 13CH4 stable isotope probing how methane produced by low affinity methane oxidising bacteria in soils is captured and used by other soil organisms. We have shown the rates at which this occurs at and how long the carbon remains in the soil before being recycled out of the systems. We achieved this developing a new methodology called Stable Isotope Switching (SIS). |
Exploitation Route | The methodology is potentially widely applicable to other biological systems in which low affinity methanotrophs are abundant. |
Sectors | Agriculture Food and Drink Environment |
Description | Lecture presented to Sustainable Food Trust meeting which resulted in an interview being recorded which was subsequently broadcast on Farming Today in 2015. |
First Year Of Impact | 2015 |
Sector | Agriculture, Food and Drink,Environment |
Impact Types | Cultural Economic |
Description | 2011, Geological Society, Burlington House, London. Paper presentation. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Talk sparked questions and discussion afterwards. To be confirmed. |
Year(s) Of Engagement Activity | 2011 |
Description | British Mass Spectrometry Society (BMSS) Stable Isotope Mass Spectrometry Users Group (SIMSUG) Meeting, Exeter, United Kingdom. |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Talk sparked questions and discussion afterwards. To be confirmed. |
Year(s) Of Engagement Activity | 2010 |
Description | CRIB Annual Meeting, 2014, University of the West of England. |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | Regional |
Primary Audience | Other academic audiences (collaborators, peers etc.) |
Results and Impact | Talk sparked questions and discussions afterwards. To be confirmed |
Year(s) Of Engagement Activity | 2014 |
Description | Methanenet Early Career Workshop, 2011, Open University. |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | Yes |
Geographic Reach | National |
Primary Audience | Undergraduate students |
Results and Impact | Talk sparked questions and discussions afterwards. To be confirmed |
Year(s) Of Engagement Activity | 2011 |