Trophic importance of kelp-derived suspended particulate matter in a through-flow sub-Antarctic system
- Kaehler, Sven, Pakhomov, E A, Kalin, R M, Davis, S
- Authors: Kaehler, Sven , Pakhomov, E A , Kalin, R M , Davis, S
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6876 , http://hdl.handle.net/10962/d1011624
- Description: Spatial dynamics of surface chlorophyll concentrations, diatom abundance and carbon and nitrogen stable isotope signatures of surface suspended particulate matter (SPM) were investigated during a bloom event observed in March 2003 in the vicinity of the sub-Antarctic Prince Edward Islands. The surface water composition was studied to estimate the overall importance and spatial extent of kelp derived SPM in the water column of the islands. It was observed that high chlorophyll concentrations (up to 2 mg m–3) between and downstream of the islands could not be explained by the development of the diatom bloom. Instead, microscopic and stable isotope analyses suggested that the chlorophyll signal was largely derived from the residual chlorophyll in fresh and decaying particles of small fragments of the kelp Macrocystis laevis, an endemic kelp species abundant along the shoreline of the islands. The findings of this study suggest that the dietary subsidy of kelp-derived carbon and nitrogen to benthic communities and possibly the plankton is not limited to the vicinity of kelp beds, but rather is a widespread phenomenon between the islands. Due to the dominating unidirectional Antarctic Circumpolar Current, large quantities of kelp-derived SPM may be transported and utilised tens of kilometres downstream of the islands.
- Full Text:
- Date Issued: 2006
- Authors: Kaehler, Sven , Pakhomov, E A , Kalin, R M , Davis, S
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6876 , http://hdl.handle.net/10962/d1011624
- Description: Spatial dynamics of surface chlorophyll concentrations, diatom abundance and carbon and nitrogen stable isotope signatures of surface suspended particulate matter (SPM) were investigated during a bloom event observed in March 2003 in the vicinity of the sub-Antarctic Prince Edward Islands. The surface water composition was studied to estimate the overall importance and spatial extent of kelp derived SPM in the water column of the islands. It was observed that high chlorophyll concentrations (up to 2 mg m–3) between and downstream of the islands could not be explained by the development of the diatom bloom. Instead, microscopic and stable isotope analyses suggested that the chlorophyll signal was largely derived from the residual chlorophyll in fresh and decaying particles of small fragments of the kelp Macrocystis laevis, an endemic kelp species abundant along the shoreline of the islands. The findings of this study suggest that the dietary subsidy of kelp-derived carbon and nitrogen to benthic communities and possibly the plankton is not limited to the vicinity of kelp beds, but rather is a widespread phenomenon between the islands. Due to the dominating unidirectional Antarctic Circumpolar Current, large quantities of kelp-derived SPM may be transported and utilised tens of kilometres downstream of the islands.
- Full Text:
- Date Issued: 2006
Alternative media: a viable option for Southern Africa?
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: text , article
- Identifier: vital:6328 , http://hdl.handle.net/10962/d1008473 , https://core.ac.uk/download/pdf/145046852.pdf
- Description: preprint , The article attempts a historically and culturally based definition of alternative media. It then gives some case studies to illustrate the efficacy of such media forms, apart from highlighting the problems associated with them. It concludes that alternative media emerge to deal with specific ideological projects and, as such, must be viewed as satisfying a specific need at a specific point in time.
- Full Text:
- Date Issued: 2006
- Authors: Banda, Fackson
- Date: 2006
- Language: English
- Type: text , article
- Identifier: vital:6328 , http://hdl.handle.net/10962/d1008473 , https://core.ac.uk/download/pdf/145046852.pdf
- Description: preprint , The article attempts a historically and culturally based definition of alternative media. It then gives some case studies to illustrate the efficacy of such media forms, apart from highlighting the problems associated with them. It concludes that alternative media emerge to deal with specific ideological projects and, as such, must be viewed as satisfying a specific need at a specific point in time.
- Full Text:
- Date Issued: 2006
The emplacement of class 1 kimberlites: part 2, petrographic evidence
- Skinner, E M W, Marsh, Julian S
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , Long abstract
- Identifier: http://hdl.handle.net/10962/132740 , vital:36878
- Description: This paper has been prepared specifically for the September 2006, Kimberlite Emplacement Workshop, Saskatoon, Canada. To this end, emphasis is placed on a big bang/ bottom-up model for the emplacement of Class 1 kimberlite pipes first presented by Clement and Reid (1989) and reinforced by Skinner and Marsh (2004). In this part (Part 2) petrographic evidence is presented in support of evidence provided by the synthesis of specific geological features as presented in Part 1.
- Full Text:
- Date Issued: 2006
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , Long abstract
- Identifier: http://hdl.handle.net/10962/132740 , vital:36878
- Description: This paper has been prepared specifically for the September 2006, Kimberlite Emplacement Workshop, Saskatoon, Canada. To this end, emphasis is placed on a big bang/ bottom-up model for the emplacement of Class 1 kimberlite pipes first presented by Clement and Reid (1989) and reinforced by Skinner and Marsh (2004). In this part (Part 2) petrographic evidence is presented in support of evidence provided by the synthesis of specific geological features as presented in Part 1.
- Full Text:
- Date Issued: 2006
Re-estimation of erosion levels in Group I and II kimberlites between Lesotho, Kimberley and Victoria West, South Africa
- Hanson, E Kelsey, Moore, John M, Robey, J, Bordy, Emese M, Marsh, Julian S
- Authors: Hanson, E Kelsey , Moore, John M , Robey, J , Bordy, Emese M , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , long abstracts
- Identifier: http://hdl.handle.net/10962/132144 , vital:36804
- Description: The estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over a 100 years. Previously postemplacement erosion levels of a small number of kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation and the depth of the initiation of diatreme facies kimberlite.
- Full Text:
- Date Issued: 2006
- Authors: Hanson, E Kelsey , Moore, John M , Robey, J , Bordy, Emese M , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , long abstracts
- Identifier: http://hdl.handle.net/10962/132144 , vital:36804
- Description: The estimation of post-emplacement kimberlite erosion in South Africa through the study of upper-crustal xenoliths is relatively unexplored; however the presence of these xenoliths has been recognized for well over a 100 years. Previously postemplacement erosion levels of a small number of kimberlite pipes have been inferred through the study of the degree of country-rock diagenesis, the depth of sill formation and the depth of the initiation of diatreme facies kimberlite.
- Full Text:
- Date Issued: 2006
Making the Invisible Visible: Ameliorating Poverty through Natural Resource Commercialisation
- Authors: Shackleton, Sheona E
- Date: 2009
- Language: English
- Type: text
- Identifier: vital:6618 , http://hdl.handle.net/10962/d1016226
- Description: [From Introduction] The majority of households in South Africa, especially those in the rural communal areas, live in abject poverty. Some 70% of rural households can be classified as poor, while 18-24% fall into the chronically poor category. Unlike many other developing nations, South Africa's rural communal areas are characterised by relatively poor availability of agricultural land, with only about 40% of rural households involved in field cropping. This results in high levels of integration and dependence on the cash economy. Unemployment levels are amongst the highest in the world at about 30%. Unemployment amongst women tends to be greater than amongst men resulting in a poverty rate amongst rural female-headed households of over 60%; double that of male-headed households. The scourge of HIV/AIDS is devastating already poor households' ability to cope. More than half of HIV/AIDS affected households have insufficient food (UNDP 2003). Impacts of the pandemic include not only the loss of income, but also increased expenditure particularly on medical care and funerals. The need to care for ill household members or orphaned children also limits the choices of occupation that other household members can pursue, and may restrict labour availability for food production. Household assets are often sold for cash eroding the few safety nets people have. HIV/AIDS is expected to contribute to a chronic impoverishment of 26-33% more households than would be the case in its absence (Aliber 2003). , Endnote: This policy brief is based on the original brief made available for a workshop in August 2006. It is derived, amongst other sources, from the findings of nine case studies of local natural resource commercialisation undertaken as part of a project funded by the South Africa-Netherlands Programme on Alternatives in Development (SANPAD), BP South Africa and the National Research Foundation (NRF). Case studies on woodcraft, furniture production, weaving, broom production and the sale of wild foods and traditional marula beer were completed by Zwoitwa Makhado (UWC), Sibongile Mavimbela (Rhodes), Taryn Pereira (Rhodes), Sheona Shackleton (Rhodes) and Jabulile Sithole (WSU). CIFOR with support from SIDA, provided the funding to share these findings with key stakeholders. The opinions expressed in these policy briefs are those of the author and research team and should not necessarily be attributed to funders and partner institutions.
- Full Text:
- Date Issued: 2009
- Authors: Shackleton, Sheona E
- Date: 2009
- Language: English
- Type: text
- Identifier: vital:6618 , http://hdl.handle.net/10962/d1016226
- Description: [From Introduction] The majority of households in South Africa, especially those in the rural communal areas, live in abject poverty. Some 70% of rural households can be classified as poor, while 18-24% fall into the chronically poor category. Unlike many other developing nations, South Africa's rural communal areas are characterised by relatively poor availability of agricultural land, with only about 40% of rural households involved in field cropping. This results in high levels of integration and dependence on the cash economy. Unemployment levels are amongst the highest in the world at about 30%. Unemployment amongst women tends to be greater than amongst men resulting in a poverty rate amongst rural female-headed households of over 60%; double that of male-headed households. The scourge of HIV/AIDS is devastating already poor households' ability to cope. More than half of HIV/AIDS affected households have insufficient food (UNDP 2003). Impacts of the pandemic include not only the loss of income, but also increased expenditure particularly on medical care and funerals. The need to care for ill household members or orphaned children also limits the choices of occupation that other household members can pursue, and may restrict labour availability for food production. Household assets are often sold for cash eroding the few safety nets people have. HIV/AIDS is expected to contribute to a chronic impoverishment of 26-33% more households than would be the case in its absence (Aliber 2003). , Endnote: This policy brief is based on the original brief made available for a workshop in August 2006. It is derived, amongst other sources, from the findings of nine case studies of local natural resource commercialisation undertaken as part of a project funded by the South Africa-Netherlands Programme on Alternatives in Development (SANPAD), BP South Africa and the National Research Foundation (NRF). Case studies on woodcraft, furniture production, weaving, broom production and the sale of wild foods and traditional marula beer were completed by Zwoitwa Makhado (UWC), Sibongile Mavimbela (Rhodes), Taryn Pereira (Rhodes), Sheona Shackleton (Rhodes) and Jabulile Sithole (WSU). CIFOR with support from SIDA, provided the funding to share these findings with key stakeholders. The opinions expressed in these policy briefs are those of the author and research team and should not necessarily be attributed to funders and partner institutions.
- Full Text:
- Date Issued: 2009
Recruitment behaviour in the ponerine ant, Plectroctena mandibularis F. Smith (Hymenoptera: Formicidae)
- Wilkins, K J, Harman, K, Villet, Martin H
- Authors: Wilkins, K J , Harman, K , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6887 , http://hdl.handle.net/10962/d1011647
- Description: Although workers of Plectroctena mandibularis laid trails with their stings while foraging, the trails appeared to be for individual orientation, because they never recruited nestmates to prey. However, both workers and queens laid trails when recruiting nestmates of either caste to new nest sites. During trail-laying, fluted hairs on the posterior edge of tergite VI were dragged along the ground, presumably applying a pheromone to the substrate. Anatomical and behavioural evidence suggests that pygidial gland secretions moved from the intersegmental pygidial gland between tergites VI and VII into a fingerprint-like, lamellar cuticular reservoir on the pygidium, and from there via the hairs to the substrate. These results suggest that recruitment may be crucial to moving nests but of value only to certain types of foraging, and that recruitment might even have originated in the Formicidae in the context of colony relocation, and then secondarily evolved to assist foraging.
- Full Text:
- Date Issued: 2006
- Authors: Wilkins, K J , Harman, K , Villet, Martin H
- Date: 2006
- Language: English
- Type: text , Article
- Identifier: vital:6887 , http://hdl.handle.net/10962/d1011647
- Description: Although workers of Plectroctena mandibularis laid trails with their stings while foraging, the trails appeared to be for individual orientation, because they never recruited nestmates to prey. However, both workers and queens laid trails when recruiting nestmates of either caste to new nest sites. During trail-laying, fluted hairs on the posterior edge of tergite VI were dragged along the ground, presumably applying a pheromone to the substrate. Anatomical and behavioural evidence suggests that pygidial gland secretions moved from the intersegmental pygidial gland between tergites VI and VII into a fingerprint-like, lamellar cuticular reservoir on the pygidium, and from there via the hairs to the substrate. These results suggest that recruitment may be crucial to moving nests but of value only to certain types of foraging, and that recruitment might even have originated in the Formicidae in the context of colony relocation, and then secondarily evolved to assist foraging.
- Full Text:
- Date Issued: 2006
Cellulases (CMCases) and polyphenol oxidases from thermophilic Bacillus spp
- Mayende, Lungisa, Wilhelmi, Brendan S, Pletschke, Brett I
- Authors: Mayende, Lungisa , Wilhelmi, Brendan S , Pletschke, Brett I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6462 , http://hdl.handle.net/10962/d1005791 , http://dx.doi.org/10.1016/j.soilbio.2006.03.019
- Description: In composting, organic matter is degraded by cellulases and ligninolytic enzymes at temperatures typically above 50 °C. This study isolated thermophilic microorganisms from a compost system that were then screened for cellulase and polyphenol oxidase activity. Temperature optima for the cellulases and polyphenol oxidases were determined as 70 and 40 °C, respectively. Maximal cellulase activity was determined as 1.333 mg glucose released ml[superscript −1] min[superscript −1]. Maximal polyphenol oxidase activity attained was 5.111 nmol phenol ml[superscript −1] min[superscript −1]. Cellulases were found to be stable over a period of 1 h. The isolated compost microorganisms were identified as strains of Bacillus using 16S ribosomal DNA sequence analysis.
- Full Text:
- Date Issued: 2006
- Authors: Mayende, Lungisa , Wilhelmi, Brendan S , Pletschke, Brett I
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6462 , http://hdl.handle.net/10962/d1005791 , http://dx.doi.org/10.1016/j.soilbio.2006.03.019
- Description: In composting, organic matter is degraded by cellulases and ligninolytic enzymes at temperatures typically above 50 °C. This study isolated thermophilic microorganisms from a compost system that were then screened for cellulase and polyphenol oxidase activity. Temperature optima for the cellulases and polyphenol oxidases were determined as 70 and 40 °C, respectively. Maximal cellulase activity was determined as 1.333 mg glucose released ml[superscript −1] min[superscript −1]. Maximal polyphenol oxidase activity attained was 5.111 nmol phenol ml[superscript −1] min[superscript −1]. Cellulases were found to be stable over a period of 1 h. The isolated compost microorganisms were identified as strains of Bacillus using 16S ribosomal DNA sequence analysis.
- Full Text:
- Date Issued: 2006
The emplacement of class 1 kimberlites: part 1, evidence of geological features
- Skinner, E M W, Marsh, Julian S
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , Long abstract
- Identifier: http://hdl.handle.net/10962/132729 , vital:36877
- Description: This paper has been prepared specifically for the September 2006, Kimberlite Emplacement Workshop, Saskatoon, Canada. To this end, emphasis is placed on a big bang/ bottom-up model for the emplacement of Class 1 kimbertite pipes first presented by Clement and Reid (1989) and reinforced by Skinner and Marsh (2004). In this part (Part 1) the evidence of various geological features is presented.
- Full Text:
- Date Issued: 2006
- Authors: Skinner, E M W , Marsh, Julian S
- Date: 2006
- Language: English
- Type: text , Long abstract
- Identifier: http://hdl.handle.net/10962/132729 , vital:36877
- Description: This paper has been prepared specifically for the September 2006, Kimberlite Emplacement Workshop, Saskatoon, Canada. To this end, emphasis is placed on a big bang/ bottom-up model for the emplacement of Class 1 kimbertite pipes first presented by Clement and Reid (1989) and reinforced by Skinner and Marsh (2004). In this part (Part 1) the evidence of various geological features is presented.
- Full Text:
- Date Issued: 2006
Ameliorating poverty in South Africa through natural resource commercialisation
- Authors: Shackleton, Sheona E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6651 , http://hdl.handle.net/10962/d1007062
- Description: This short policy brief advocates for more attention to be paid to the potential of natural resource commercialisation as a means to livelihood security and poverty alleviation in rural South Africa. It is one of a set of four policy briefs based on the findings of several case studies across the country.
- Full Text:
- Date Issued: 2006
- Authors: Shackleton, Sheona E
- Date: 2006
- Language: English
- Type: Article
- Identifier: vital:6651 , http://hdl.handle.net/10962/d1007062
- Description: This short policy brief advocates for more attention to be paid to the potential of natural resource commercialisation as a means to livelihood security and poverty alleviation in rural South Africa. It is one of a set of four policy briefs based on the findings of several case studies across the country.
- Full Text:
- Date Issued: 2006
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