A preliminary study on the effects of elevated CO2 on aphid resistance of Tugela Dn and the population dynamics of the Russian wheat aphid (Homoptera: Aphididae), Diuraphis noxia
- Authors: Mundondo, Daphine
- Date: 2015
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11402 , http://hdl.handle.net/10353/d1020244
- Description: Food security is of major importance due to the increasing world population with 8.9 billion people expected by 2050 (Cohen, 2003). Diuraphis noxia (RWA), have caused aggravating, massive losses to wheat farmers in many areas of the world. If unchecked, RWA are able to destroy plants resulting in major economic impacts (Botha, 2013). Due to ineffective use of other control methods, the Small Grains Institute in Bethlehem, South Africa, have therefore developed resistant cultivars to the known RWA subtypes over the past decades through intensive breeding programmes (Tolmay et al., 2006). Climate change has however become a major factor threatening food security especially with the observed increase in CO2 from less than 300 ppm in pre-industrial period to the current 385 ppm and is predicted to reach 550 ppm by 2050 (IPCC, 2007; Meehl et al., 2007). Elevated CO2 concentration may affect individual species of a community hence the need to understand the wheat-aphid interactions. In this study, population growth rates and virulence of RWA SA1 at ambient (385 ppm) and elevated (450 ppm) CO2 concentration were evaluated on two wheat cultivars: Tugela Dn (resistant) and Scheepers (susceptible). Fluorescence microscopy techniques using aniline blue were used to investigate feeding related damage caused by RWA SA1 through an examination of callose deposition at the two CO2 concentration. A two-dimensional gel electrophoresis method was developed in order to determine the effect of RWA SA1 on the wheat cultivars proteome at the two CO2 concentration. Differentially expressed proteins that were up or down regulated more than two fold were identified using PDQuestTM Basic 2D Gel analysis software. Populations of RWA SA1 increased significantly on the two wheat cultivars at both CO2 concentration. Although the population growth rate for RWA SA1 on both cultivars was generally exponential at all treatments, growth at elevated CO2 concentration was noticeably faster with populations increasing 3 fold in 14 days as compared to the 2 times at ambient CO2 concentration. Hence, both cultivars provided a better quality host for RWA SA1 at 450 ppm than 385 ppm. There was no significant difference between RWA SA1 population on Tugela Dn and on Scheepers at elevated CO2 concentration on day 14 after infestation which means there was a change in the resistance mechanism in Tugela Dn at this condition. Approximately 70% of the total leaf showed chlorosis by 21 days of aphid infestation for both cultivars although the susceptible cultivar was more vulnerable. There was low callose deposition in the controls (uninfested plants) but heavy callose in infested plants due to aphid feeding. A proteomics approach was used as a pilot study to investigate whether it would be possible to identify the changes in the resistance mechanism during aphid infestation under elevated CO2 levels. The major changes in the proteome of the control group (uninfested Tugela Dn at ambient versus elevated CO2 concentration) occurred in the early events (day 1-7) in the molecular weight range of approximately 25 kDa to 55 kDa are mainly within the basic to neutral pH range. This was suggested to be a result of mechanisms to adjust to the CO2 concentration. Elevated CO2 results in instant higher photosynthetic rates and C:N ratios as well as changes in expression levels of SA-dependant defense genes (Lindroth 1995; Hughes and Bazzaz, 2001; Sun et al., 2013). Because most of these changes are directly regulated by proteins, it is expected that the most differential protein expression will occur immediately after the atmospheric changes (early events) as was shown in the study. Infested plants under elevated and ambient conditions showed that the stress conditions gave rise to differentially regulated proteins within the wheat proteome. Most changes occurred elevated CO2 levels. It can be suggested that the changes were a result of differentially regulated plant defence proteins which fall in this range (25 kDa - 80 kDa) such as peroxidases, chitinases and β-1.3-glucanases as well as protein kinases, heat-shock proteins and photosynthetic proteins. These results indicate that there has been changes in the resistance due to elevated CO2 because of the evident changes in the proteome. If so, then the results will be similar to those documented by Louw (2007) where up-regulation was due to putative storage proteins, proteins involved in photosynthesis, heat shock proteins and defense proteins. Of course, the pI value and molecular mass of the proteins and the identification of the proteins in these spots, must be determined in future work to specifically identify whether these suggestions are authentic. However, Louw (2007) also reports that the susceptible Betta wheat cultivar, displayed a defence response similar to the HR although it was unable to up-regulate specific defensive proteins against RWA infestation but proteins for broad resistance. Although the changes in the proteins in infested Tugela Dn under elevated CO2 concentration were not accurately identified, the defense mechanism is similar to that portrayed by the susceptible Betta wheat cultivar which shows that the resistance mechanism had been overcome. Because this was a pilot study and preliminary results were obtained due to limited funding and time constraints, suggestions were made on how to further develop the method to obtain statistically significant results.
- Full Text:
- Date Issued: 2015
- Authors: Mundondo, Daphine
- Date: 2015
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11402 , http://hdl.handle.net/10353/d1020244
- Description: Food security is of major importance due to the increasing world population with 8.9 billion people expected by 2050 (Cohen, 2003). Diuraphis noxia (RWA), have caused aggravating, massive losses to wheat farmers in many areas of the world. If unchecked, RWA are able to destroy plants resulting in major economic impacts (Botha, 2013). Due to ineffective use of other control methods, the Small Grains Institute in Bethlehem, South Africa, have therefore developed resistant cultivars to the known RWA subtypes over the past decades through intensive breeding programmes (Tolmay et al., 2006). Climate change has however become a major factor threatening food security especially with the observed increase in CO2 from less than 300 ppm in pre-industrial period to the current 385 ppm and is predicted to reach 550 ppm by 2050 (IPCC, 2007; Meehl et al., 2007). Elevated CO2 concentration may affect individual species of a community hence the need to understand the wheat-aphid interactions. In this study, population growth rates and virulence of RWA SA1 at ambient (385 ppm) and elevated (450 ppm) CO2 concentration were evaluated on two wheat cultivars: Tugela Dn (resistant) and Scheepers (susceptible). Fluorescence microscopy techniques using aniline blue were used to investigate feeding related damage caused by RWA SA1 through an examination of callose deposition at the two CO2 concentration. A two-dimensional gel electrophoresis method was developed in order to determine the effect of RWA SA1 on the wheat cultivars proteome at the two CO2 concentration. Differentially expressed proteins that were up or down regulated more than two fold were identified using PDQuestTM Basic 2D Gel analysis software. Populations of RWA SA1 increased significantly on the two wheat cultivars at both CO2 concentration. Although the population growth rate for RWA SA1 on both cultivars was generally exponential at all treatments, growth at elevated CO2 concentration was noticeably faster with populations increasing 3 fold in 14 days as compared to the 2 times at ambient CO2 concentration. Hence, both cultivars provided a better quality host for RWA SA1 at 450 ppm than 385 ppm. There was no significant difference between RWA SA1 population on Tugela Dn and on Scheepers at elevated CO2 concentration on day 14 after infestation which means there was a change in the resistance mechanism in Tugela Dn at this condition. Approximately 70% of the total leaf showed chlorosis by 21 days of aphid infestation for both cultivars although the susceptible cultivar was more vulnerable. There was low callose deposition in the controls (uninfested plants) but heavy callose in infested plants due to aphid feeding. A proteomics approach was used as a pilot study to investigate whether it would be possible to identify the changes in the resistance mechanism during aphid infestation under elevated CO2 levels. The major changes in the proteome of the control group (uninfested Tugela Dn at ambient versus elevated CO2 concentration) occurred in the early events (day 1-7) in the molecular weight range of approximately 25 kDa to 55 kDa are mainly within the basic to neutral pH range. This was suggested to be a result of mechanisms to adjust to the CO2 concentration. Elevated CO2 results in instant higher photosynthetic rates and C:N ratios as well as changes in expression levels of SA-dependant defense genes (Lindroth 1995; Hughes and Bazzaz, 2001; Sun et al., 2013). Because most of these changes are directly regulated by proteins, it is expected that the most differential protein expression will occur immediately after the atmospheric changes (early events) as was shown in the study. Infested plants under elevated and ambient conditions showed that the stress conditions gave rise to differentially regulated proteins within the wheat proteome. Most changes occurred elevated CO2 levels. It can be suggested that the changes were a result of differentially regulated plant defence proteins which fall in this range (25 kDa - 80 kDa) such as peroxidases, chitinases and β-1.3-glucanases as well as protein kinases, heat-shock proteins and photosynthetic proteins. These results indicate that there has been changes in the resistance due to elevated CO2 because of the evident changes in the proteome. If so, then the results will be similar to those documented by Louw (2007) where up-regulation was due to putative storage proteins, proteins involved in photosynthesis, heat shock proteins and defense proteins. Of course, the pI value and molecular mass of the proteins and the identification of the proteins in these spots, must be determined in future work to specifically identify whether these suggestions are authentic. However, Louw (2007) also reports that the susceptible Betta wheat cultivar, displayed a defence response similar to the HR although it was unable to up-regulate specific defensive proteins against RWA infestation but proteins for broad resistance. Although the changes in the proteins in infested Tugela Dn under elevated CO2 concentration were not accurately identified, the defense mechanism is similar to that portrayed by the susceptible Betta wheat cultivar which shows that the resistance mechanism had been overcome. Because this was a pilot study and preliminary results were obtained due to limited funding and time constraints, suggestions were made on how to further develop the method to obtain statistically significant results.
- Full Text:
- Date Issued: 2015
A sociological analysis of the production, marketing and distribution of contemporary popular music by Zambian musicians
- Authors: Kazadi, Kanyabu Solomon
- Date: 2015
- Subjects: Popular music -- Zambia , Musicians -- Zambia , Sound recording industry -- Zambia , Popular music -- Production and direction -- Zambia , Popular music -- Marketing , Intellectual property -- Zambia , Copyright -- Royalties -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3404 , http://hdl.handle.net/10962/d1018933
- Description: The purpose of this research was to gather information about the production, marketing and distribution of Zambian contemporary music by Zambian musicians. Very little information has been documented about the development of the Zambian music industry, particularly from the perspective of those within the industry. As a result this study attempted to add to this knowledge. To achieve this Pierre Bourdieu’s theoretical concepts of ‘fields’ and ‘habitus’ were used to gain an understanding of what affects the creation of art forms such as music as well as the structures and underlying processes within the music industry. The concept of ‘fields’ usefully framed an explanation of the struggles and connections within the various fields in the industry and a view of the Zambian music industry in relation to the international industry. To gather the data necessary for this research a qualitative approach was utilised involving semistructured in-depth questionnaires from twenty-three interviewees. These interviewees were selected from various sectors of the music industry in an attempt to gain a holistic perspective of the industry in the 21st century. There were four subgroups: the artists (singers, rappers and instrumentalists), managers, radio DJs, and a miscellaneous group made up of the remaining participants, a Sounds Arcade manager, a music journalist, the National Arts Council Chairperson, a Zambia Music Copyright Protection Society (ZAMCOPS) administrator, and the then President of the Zambia Association of Musicians (ZAM). With the limited exposure to formal musical, instrumental and production training, musicians, instrumentalists, managers and studio production personnel interviewed had had to learn their craft on-the-job. This limited knowledge appears to add to the hindrance of the development of careers and the industry, particularly in terms of how to register and distribute music correctly to earn royalties and protect their intellectual property against piracy. From an institutional level piracy is being addressed more forcefully with the introduction of holograms and the tightening of policies and structures to do with the music industry.
- Full Text:
- Date Issued: 2015
- Authors: Kazadi, Kanyabu Solomon
- Date: 2015
- Subjects: Popular music -- Zambia , Musicians -- Zambia , Sound recording industry -- Zambia , Popular music -- Production and direction -- Zambia , Popular music -- Marketing , Intellectual property -- Zambia , Copyright -- Royalties -- Zambia
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:3404 , http://hdl.handle.net/10962/d1018933
- Description: The purpose of this research was to gather information about the production, marketing and distribution of Zambian contemporary music by Zambian musicians. Very little information has been documented about the development of the Zambian music industry, particularly from the perspective of those within the industry. As a result this study attempted to add to this knowledge. To achieve this Pierre Bourdieu’s theoretical concepts of ‘fields’ and ‘habitus’ were used to gain an understanding of what affects the creation of art forms such as music as well as the structures and underlying processes within the music industry. The concept of ‘fields’ usefully framed an explanation of the struggles and connections within the various fields in the industry and a view of the Zambian music industry in relation to the international industry. To gather the data necessary for this research a qualitative approach was utilised involving semistructured in-depth questionnaires from twenty-three interviewees. These interviewees were selected from various sectors of the music industry in an attempt to gain a holistic perspective of the industry in the 21st century. There were four subgroups: the artists (singers, rappers and instrumentalists), managers, radio DJs, and a miscellaneous group made up of the remaining participants, a Sounds Arcade manager, a music journalist, the National Arts Council Chairperson, a Zambia Music Copyright Protection Society (ZAMCOPS) administrator, and the then President of the Zambia Association of Musicians (ZAM). With the limited exposure to formal musical, instrumental and production training, musicians, instrumentalists, managers and studio production personnel interviewed had had to learn their craft on-the-job. This limited knowledge appears to add to the hindrance of the development of careers and the industry, particularly in terms of how to register and distribute music correctly to earn royalties and protect their intellectual property against piracy. From an institutional level piracy is being addressed more forcefully with the introduction of holograms and the tightening of policies and structures to do with the music industry.
- Full Text:
- Date Issued: 2015
Experiences of incarcerated women who have committed intimate partner homicide
- Authors: Coombs-Brown, Chanelle
- Date: 2015
- Subjects: Incarcerated women Female offenders Women--Violence against
- Language: English
- Type: Thesis , Masters , Psychology
- Identifier: http://hdl.handle.net/10353/17406 , vital:40965
- Description: This qualitative study explores the experiences of incarcerated women who have perpetrated intimate partner homicide (IPH) and had been exposed to intimate partner violence (IPV) in their relationships. The study further explores women’s experiences of IPV, in particular those which motivated them to perpetrate IPH. The study examines how factors associated with IPV affect women to the point of responding with such lethal IPH. Additionally, it explores whether or not women feel remorse for their actions of IPH. The current study falls within an interpretive research paradigm and employs interpretative phenomenological analysis (IPA) as its theoretical framework. The researcher selected IPA as it works well in understanding and describing participants’ experiences. Semi-structured face to face interviews were conducted with nine women incarcerated for IPH. The findings of the study were analysed using the IPA approach. Three main themes emerged from the analysis: mainly all women reported to have experienced IPV in their respective relationships with the deceased, all, except one woman, reported that their partners had committed infidelity, the women also reported to have experienced much disappointment in gaining assistance from the judicial system. Therefore, on-going IPV including death threats resulted in fear; infidelity resulted in tremendous emotional and psychological strain, as well as feelings of betrayal; and perceived lack of support from the judicial system all appeared to have motivated women to perpetrate IPH with the majority indicating remorse.
- Full Text:
- Date Issued: 2015
- Authors: Coombs-Brown, Chanelle
- Date: 2015
- Subjects: Incarcerated women Female offenders Women--Violence against
- Language: English
- Type: Thesis , Masters , Psychology
- Identifier: http://hdl.handle.net/10353/17406 , vital:40965
- Description: This qualitative study explores the experiences of incarcerated women who have perpetrated intimate partner homicide (IPH) and had been exposed to intimate partner violence (IPV) in their relationships. The study further explores women’s experiences of IPV, in particular those which motivated them to perpetrate IPH. The study examines how factors associated with IPV affect women to the point of responding with such lethal IPH. Additionally, it explores whether or not women feel remorse for their actions of IPH. The current study falls within an interpretive research paradigm and employs interpretative phenomenological analysis (IPA) as its theoretical framework. The researcher selected IPA as it works well in understanding and describing participants’ experiences. Semi-structured face to face interviews were conducted with nine women incarcerated for IPH. The findings of the study were analysed using the IPA approach. Three main themes emerged from the analysis: mainly all women reported to have experienced IPV in their respective relationships with the deceased, all, except one woman, reported that their partners had committed infidelity, the women also reported to have experienced much disappointment in gaining assistance from the judicial system. Therefore, on-going IPV including death threats resulted in fear; infidelity resulted in tremendous emotional and psychological strain, as well as feelings of betrayal; and perceived lack of support from the judicial system all appeared to have motivated women to perpetrate IPH with the majority indicating remorse.
- Full Text:
- Date Issued: 2015
Montane Wetlands of the South African Great Escarpment : plant communities and environmental drivers
- Authors: Janks, Matthew Richard
- Date: 2015
- Subjects: Mountain plants -- South Africa -- Eastern Cape , Wetland plants -- South Africa -- Eastern Cape , Wetland plants -- Effect of altitude on -- South Africa -- Eastern Cape , Wetland ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4274 , http://hdl.handle.net/10962/d1018917
- Description: Wetlands provide a number of valuable functions to both the surrounding environment and society. The anaerobic conditions created by flooding in wetlands provide a habitat that supports unique assemblages of plant life. High altitude wetlands are amongst the most species-rich in South Africa. They house a number of rare species and play a vital role in the supply of water to lower lying areas. These are some of the reasons that mountain wetlands are of high conservation value. A phytosociological study was undertaken on the high altitude wetlands of the Great Escarpment with the aim of classifying the plant communities and identifying the environmental drivers of plant community patterns within these ecosystems. Data collection was focused in the Eastern Cape and was supplemented with data from existing studies to gain a more complete understanding of the wetlands of the Great Escarpment of South Africa. Using the Braun-Blanquet approach, Hierarchical Cluster Analysis and Indicator Species Analysis; five broad wetland groups were identified, comprised of 33 individual plant communities and 81 indicator species. Multivariate analysis, including Canonical Correspondence Analysis revealed that the effects of altitude, such as temperature and rainfall, are the most significant large-scale drivers of vegetation patterns. Smaller scale drivers include wetness and soil nutrients including nitrogen, phosphorus, electrical conductivity, sodium, and organic content. The identification of indicator species served to reveal potentially important wetland species across different areas of the Great Escarpment. The effects of altitude on plant community patterns highlights the susceptibility of the high altitude specific communities to upward temperature zone shifts resulting from global warming. Other threats include livestock trampling, water extraction, and land use change for agricultural purposes. The relative absence of alien species in these wetlands gives an indication of their pristine condition and therefore their importance as a reference from which they may be monitored. A large proportion of the wetlands studied here occur outside protected areas, and given the rate of wetland loss in South Africa, it is important that continued effective land management is practiced to ensure that these ecosystems are conserved in the future .
- Full Text:
- Date Issued: 2015
Montane Wetlands of the South African Great Escarpment : plant communities and environmental drivers
- Authors: Janks, Matthew Richard
- Date: 2015
- Subjects: Mountain plants -- South Africa -- Eastern Cape , Wetland plants -- South Africa -- Eastern Cape , Wetland plants -- Effect of altitude on -- South Africa -- Eastern Cape , Wetland ecology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4274 , http://hdl.handle.net/10962/d1018917
- Description: Wetlands provide a number of valuable functions to both the surrounding environment and society. The anaerobic conditions created by flooding in wetlands provide a habitat that supports unique assemblages of plant life. High altitude wetlands are amongst the most species-rich in South Africa. They house a number of rare species and play a vital role in the supply of water to lower lying areas. These are some of the reasons that mountain wetlands are of high conservation value. A phytosociological study was undertaken on the high altitude wetlands of the Great Escarpment with the aim of classifying the plant communities and identifying the environmental drivers of plant community patterns within these ecosystems. Data collection was focused in the Eastern Cape and was supplemented with data from existing studies to gain a more complete understanding of the wetlands of the Great Escarpment of South Africa. Using the Braun-Blanquet approach, Hierarchical Cluster Analysis and Indicator Species Analysis; five broad wetland groups were identified, comprised of 33 individual plant communities and 81 indicator species. Multivariate analysis, including Canonical Correspondence Analysis revealed that the effects of altitude, such as temperature and rainfall, are the most significant large-scale drivers of vegetation patterns. Smaller scale drivers include wetness and soil nutrients including nitrogen, phosphorus, electrical conductivity, sodium, and organic content. The identification of indicator species served to reveal potentially important wetland species across different areas of the Great Escarpment. The effects of altitude on plant community patterns highlights the susceptibility of the high altitude specific communities to upward temperature zone shifts resulting from global warming. Other threats include livestock trampling, water extraction, and land use change for agricultural purposes. The relative absence of alien species in these wetlands gives an indication of their pristine condition and therefore their importance as a reference from which they may be monitored. A large proportion of the wetlands studied here occur outside protected areas, and given the rate of wetland loss in South Africa, it is important that continued effective land management is practiced to ensure that these ecosystems are conserved in the future .
- Full Text:
- Date Issued: 2015
On active layer processes and landforms in western Dronning Maud Land, Antarctica
- Authors: Scott, David Alan
- Date: 2015
- Subjects: Landforms -- Antarctica -- Queen Maud Land , Permafrost -- Antarctica -- Queen Maud Land , Permafrost -- Thermal properties -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Cryosphere , Drone aircraft -- Antarctica -- Queen Maud Land , 3-D modeling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4893 , http://hdl.handle.net/10962/d1019757
- Description: Permafrost is a variable in Antarctic terrestrial ecosystems, and the role it plays in the cryosphere is not well understood. There is much still to be learnt about the thermal state, physical properties, thickness and age of permafrost in Western Dronning Maud Land (WDML). Active layer dynamics and observed change over time have the potential to improve our knowledge of climate change. Understanding the effects of a warming climate on permafrost can also be of benefit to infrastructure, especially in areas with a large amount of frozen ground such as Scandinavia, Canada and Russia. Active layer and permafrost dynamics of WDML, Antarctica, are presented and discussed using data from six study sites, namely the Robertskollen, Vesleskarvet, Flarjuven, Grunehogna, Slettjfell nunataks and the Troll research station in the Jutulsessen area. Ground and ambient air temperature, as well as ground moisture data were collected for each site. An inventory of active layer and permafrost landforms was compiled, as were the frequency of cycles over the zero-degree isotherm, and the depth of the active layer. Furthermore, 3D models, geo-referenced maps and Digital Elevation Models were created of study areas with the use of an Unmanned Aerial Vehicle (UAV). Polygonal features are the most common landscape feature and are common to most of the study sites. Robertskollen has the deepest active layer at over 66cm and Slettfjell the shallowest at 9cm. A maximum recorded air temperature of 8.76°C (10/11/2014) occurred at Troll with the second highest maximum of 6.77°C (22/12/2010) recorded at Vesleskarvet. Robertskollen has the highest observable biological growth and a maximum recorded ground temperature of 22.84°C (10/01/2014). Troll and Valterkulten, registered the second and third highest ground temperatures respectively. The high ground Temperature observed for Robertskollen may be ascribed to it being the lowest altitude site. The highest number of cycles over the zero-degree isotherm was observed at Troll (11.01%), followed by Robertskollen (10.99%). For relatively warm areas, such as Robertskollen it is recommended that two metre borehole loggers are installed in order to capture a detailed understanding of the active layer. The UAV proved to be a beneficial tool for capturing aerial photographs for post fieldwork analysis and 3D modelling.
- Full Text:
- Date Issued: 2015
- Authors: Scott, David Alan
- Date: 2015
- Subjects: Landforms -- Antarctica -- Queen Maud Land , Permafrost -- Antarctica -- Queen Maud Land , Permafrost -- Thermal properties -- Antarctica -- Queen Maud Land , Climatic changes -- Antarctica -- Queen Maud Land , Cryosphere , Drone aircraft -- Antarctica -- Queen Maud Land , 3-D modeling
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4893 , http://hdl.handle.net/10962/d1019757
- Description: Permafrost is a variable in Antarctic terrestrial ecosystems, and the role it plays in the cryosphere is not well understood. There is much still to be learnt about the thermal state, physical properties, thickness and age of permafrost in Western Dronning Maud Land (WDML). Active layer dynamics and observed change over time have the potential to improve our knowledge of climate change. Understanding the effects of a warming climate on permafrost can also be of benefit to infrastructure, especially in areas with a large amount of frozen ground such as Scandinavia, Canada and Russia. Active layer and permafrost dynamics of WDML, Antarctica, are presented and discussed using data from six study sites, namely the Robertskollen, Vesleskarvet, Flarjuven, Grunehogna, Slettjfell nunataks and the Troll research station in the Jutulsessen area. Ground and ambient air temperature, as well as ground moisture data were collected for each site. An inventory of active layer and permafrost landforms was compiled, as were the frequency of cycles over the zero-degree isotherm, and the depth of the active layer. Furthermore, 3D models, geo-referenced maps and Digital Elevation Models were created of study areas with the use of an Unmanned Aerial Vehicle (UAV). Polygonal features are the most common landscape feature and are common to most of the study sites. Robertskollen has the deepest active layer at over 66cm and Slettfjell the shallowest at 9cm. A maximum recorded air temperature of 8.76°C (10/11/2014) occurred at Troll with the second highest maximum of 6.77°C (22/12/2010) recorded at Vesleskarvet. Robertskollen has the highest observable biological growth and a maximum recorded ground temperature of 22.84°C (10/01/2014). Troll and Valterkulten, registered the second and third highest ground temperatures respectively. The high ground Temperature observed for Robertskollen may be ascribed to it being the lowest altitude site. The highest number of cycles over the zero-degree isotherm was observed at Troll (11.01%), followed by Robertskollen (10.99%). For relatively warm areas, such as Robertskollen it is recommended that two metre borehole loggers are installed in order to capture a detailed understanding of the active layer. The UAV proved to be a beneficial tool for capturing aerial photographs for post fieldwork analysis and 3D modelling.
- Full Text:
- Date Issued: 2015
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