Towards a changed view on greenhouse gas exchange in the Arctic: new findings and improved techniques
(2010) In Meddelanden från Lunds universitets geografiska institution. Avhandlingar 188.- Abstract
- Arctic ecosystems represent an important component in the global terrestrial exchange of greenhouse gases and energy with the atmosphere. In the changing climate, which is most pronounced in the Arctic, the possible scenarios of greenhouse gas exchange response should be seriously considered in predictive climate modelling efforts. As a prerequisite for this, detailed studies of key processes affecting greenhouse gas exchange in the Arctic are important, as well as monitoring of its current dynamics. However, the number of such studies, carried on in high Northern latitudes is significantly smaller than for lower latitudes, and within the existing studies there is a bias towards studying the growing season.
The main aim of this... (More) - Arctic ecosystems represent an important component in the global terrestrial exchange of greenhouse gases and energy with the atmosphere. In the changing climate, which is most pronounced in the Arctic, the possible scenarios of greenhouse gas exchange response should be seriously considered in predictive climate modelling efforts. As a prerequisite for this, detailed studies of key processes affecting greenhouse gas exchange in the Arctic are important, as well as monitoring of its current dynamics. However, the number of such studies, carried on in high Northern latitudes is significantly smaller than for lower latitudes, and within the existing studies there is a bias towards studying the growing season.
The main aim of this study was to improve our process understanding of greenhouse gas exchange in the Arctic terrestrial ecosystems, including the processes taking place at low temperatures and outside the growing season. In order to achieve this some development in measurement techniques, such as automatic closed and flow-through chambers, adapted for monitoring CH4 and CO2 exchange under Arctic conditions, membrane diffusion probes to study subsurface profiles of these gases, laboratory techniques of low-temperature incubation and gas exchange studies on permafrost samples.
During the studies, some novel results were obtained, such as on detailed multiseasonal CH4 emission dynamics in a high Arctic fen, on late-season bursts of CH4 and CO2 at Greenland and Svalbard, and in relation to respiration and its origin in old permafrost.
Four years of CH4 emission monitoring data have shown that the exchange of this greenhouse gas under truly Arctic conditions is having some very special dynamics and different dominating controlling factors compared with conventional knowledge from lower latitudes. The patterns of growing season CH4 emission are highly dependent on the snow melt date. The greatest variations in fluxes between the study years was observed during the first 30-40 days after snow melt. This variability could not be explained by common factors controlling methane emission at lower latitudes: temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years, this despite large differences in ambient and climatic factors. In this study we try to explain these unusual patterns.
Late-season bursts of CH4 and CO2 coinciding with soil freezing after growing season was observed and documented in North-Eastern Greenland. A similar burst of CO2 at freezing time was documented on Svalbard. The accumulated emission during the freezing-season CH4 burst was found to be comparable in size with the growing season emission. In the study we also make an attempt to explain this phenomenon.
Finally samples of permafrost soils up to 500 thousands years old were found to contain living microorganisms of the same age, continuing methabolic activity and CO2 production. In this study we try to explain this unique feature of permafrost inhabitants. (Less) - Abstract (Swedish)
- Popular Abstract in Swedish
Arktiska ekosystem utgör en viktig del av det globala terrestra utbytet av växthusgaser och energi med atmosfären. I ett klimat som förändras, särskilt uttalat i Arktisk, bör tänkbara framtidsprognoser av växthusgasutbytet från dessa områden övervägas noga när framtida klimat modelleras. En förutsättning för detta är detaljerade studier av nyckelprocesser som påverkar växthusgasutbytet i Arktis, liksom övervakning av dynamiken av dessa processer. Antalet studier i de nordligaste områdena är dock betydligt färre än för sydligare breddgrader och bland de studier som finns är de flesta utförda under växtsäsongen.
Syftet med denna studien har varit att öka förståelsen för växthusgasutbytet i... (More) - Popular Abstract in Swedish
Arktiska ekosystem utgör en viktig del av det globala terrestra utbytet av växthusgaser och energi med atmosfären. I ett klimat som förändras, särskilt uttalat i Arktisk, bör tänkbara framtidsprognoser av växthusgasutbytet från dessa områden övervägas noga när framtida klimat modelleras. En förutsättning för detta är detaljerade studier av nyckelprocesser som påverkar växthusgasutbytet i Arktis, liksom övervakning av dynamiken av dessa processer. Antalet studier i de nordligaste områdena är dock betydligt färre än för sydligare breddgrader och bland de studier som finns är de flesta utförda under växtsäsongen.
Syftet med denna studien har varit att öka förståelsen för växthusgasutbytet i arktiska terrestra ekosystem, inklusive de processer som pågår vid låga temperaturer och utanför växtsäsongen. För att uppnå detta har utveckling skett av mättekniker, som till exempel automatiskt stängda- och genomsläpps-kamrar särskilt anpassade för övervakning av CH4- och CO2-utbytet under Arktiska förhållanden, membran-sonder för att studera profiler av dessa gaser under markytan, samt laboratorietekniker där inkubation och växthusgasutbyte vid låga temperaturer har studerats på permafrostjordar.
Under denna studie framkom hittills okända resultat, som till exempel detaljerad CH4 dynamik från flera säsonger från en arktisk myr, sent säsongsutsläpp av CH4 och CO2 på Grönland och Svalbard, i samband med respiration och dess ursprung i gammal permafrost.
Fyra års övervakning av CH4 visar att utbytet av denna växthusgas har väldigt speciell dynamik i Arktiska förhållanden och kontrolleras av andra faktorer jämfört med vad som styr dynamiken på sydligare breddgrader. Växtsäsongens utsläppsmönster av CH4 beror här till stor del på när snösmältningen sker. Den största variationen i metanflöden återfanns således under de första 30-40 dagarna efter snösmältningen. Denna variation kunde inte förklaras av vad som vanligtvis kontrollerar metanutsläppen vid lägre latituder: temperatur och grundvattennivån. Sent under växtsäsongen var utsläppen av metan väldigt lika under perioden dessa studerats, detta trots stora skillnader i klimat. I denna studien försöker vi förklara dessa ovanliga utsläppsmönster.
Stora utsläpp av CH4 och CO2 som sammanföll med infrysning av marken efter växtsäsongen har observerats och dokumenterats på Nordöstra Grönland. Ett liknande utsläpp av CO2 har även dokumenterats på Svalbard vid infrysning av marken. De ackumulerade utsläppen av dessa utsläpp efter växtsäsongen visade sig vara av liknande storlek med utsläppen som skedde under hela växtsäsongen. I denna studie försöker vi förklara detta tidigare okända fenomen.
Slutligen upptäcktes levande organismer som var upp till 500 000 år gamla i jordprover från permafrostområde, där nedbrytningsprocesser och CO2 produktion fortfarande pågick. I denna studien försöker vi förklara denna unika företeelse om dessa permafrostinvånare. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/1579013
- author
- Mastepanov, Mikhail LU
- supervisor
- opponent
-
- prof. Ineson, Phil, University of York, UK
- organization
- publishing date
- 2010
- type
- Thesis
- publication status
- published
- subject
- keywords
- methane, carbon dioxide, greenhouse gas, chamber, Arctic, fen, permafrost
- in
- Meddelanden från Lunds universitets geografiska institution. Avhandlingar
- volume
- 188
- pages
- 141 pages
- publisher
- Lund University
- defense location
- salen Världen, Geocentrum I, Sölvegatan 10, Lund
- defense date
- 2010-04-16 10:00:00
- external identifiers
-
- scopus:77953012180
- ISSN
- 0346-6787
- ISBN
- 978-91-85793-15-0
- language
- English
- LU publication?
- yes
- id
- b4817475-f579-4321-9aaa-70e516e39a3a (old id 1579013)
- date added to LUP
- 2016-04-01 13:18:29
- date last changed
- 2022-01-27 18:29:49
@phdthesis{b4817475-f579-4321-9aaa-70e516e39a3a,
abstract = {{Arctic ecosystems represent an important component in the global terrestrial exchange of greenhouse gases and energy with the atmosphere. In the changing climate, which is most pronounced in the Arctic, the possible scenarios of greenhouse gas exchange response should be seriously considered in predictive climate modelling efforts. As a prerequisite for this, detailed studies of key processes affecting greenhouse gas exchange in the Arctic are important, as well as monitoring of its current dynamics. However, the number of such studies, carried on in high Northern latitudes is significantly smaller than for lower latitudes, and within the existing studies there is a bias towards studying the growing season.<br/><br>
The main aim of this study was to improve our process understanding of greenhouse gas exchange in the Arctic terrestrial ecosystems, including the processes taking place at low temperatures and outside the growing season. In order to achieve this some development in measurement techniques, such as automatic closed and flow-through chambers, adapted for monitoring CH4 and CO2 exchange under Arctic conditions, membrane diffusion probes to study subsurface profiles of these gases, laboratory techniques of low-temperature incubation and gas exchange studies on permafrost samples.<br/><br>
During the studies, some novel results were obtained, such as on detailed multiseasonal CH4 emission dynamics in a high Arctic fen, on late-season bursts of CH4 and CO2 at Greenland and Svalbard, and in relation to respiration and its origin in old permafrost.<br/><br>
Four years of CH4 emission monitoring data have shown that the exchange of this greenhouse gas under truly Arctic conditions is having some very special dynamics and different dominating controlling factors compared with conventional knowledge from lower latitudes. The patterns of growing season CH4 emission are highly dependent on the snow melt date. The greatest variations in fluxes between the study years was observed during the first 30-40 days after snow melt. This variability could not be explained by common factors controlling methane emission at lower latitudes: temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years, this despite large differences in ambient and climatic factors. In this study we try to explain these unusual patterns.<br/><br>
Late-season bursts of CH4 and CO2 coinciding with soil freezing after growing season was observed and documented in North-Eastern Greenland. A similar burst of CO2 at freezing time was documented on Svalbard. The accumulated emission during the freezing-season CH4 burst was found to be comparable in size with the growing season emission. In the study we also make an attempt to explain this phenomenon.<br/><br>
Finally samples of permafrost soils up to 500 thousands years old were found to contain living microorganisms of the same age, continuing methabolic activity and CO2 production. In this study we try to explain this unique feature of permafrost inhabitants.}},
author = {{Mastepanov, Mikhail}},
isbn = {{978-91-85793-15-0}},
issn = {{0346-6787}},
keywords = {{methane; carbon dioxide; greenhouse gas; chamber; Arctic; fen; permafrost}},
language = {{eng}},
publisher = {{Lund University}},
school = {{Lund University}},
series = {{Meddelanden från Lunds universitets geografiska institution. Avhandlingar}},
title = {{Towards a changed view on greenhouse gas exchange in the Arctic: new findings and improved techniques}},
volume = {{188}},
year = {{2010}},
}