Balancing water for food and environment : hydrological determinants across scales in the Thukela River Basin.

Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2008.In this study, geophysical measurements (Electrical Resistivity Tomography-ERT) and remote sensing techniques were applied in the Thukela river basin at various scales to complement the classical hydrometeorological networks. Detailed process hydrological studies were carried out at the Potshini catchment in the Thukela river basin to provide an in-depth understanding of the influence of different land use management practices, notably the impact of conservation tiJlage practices, on runoff generation and soil moisture retention characteristics at field scale. The general trend that was observed in the field studies is that conservation tillage systems influenced the partitioning of rainfall, by significantly reducing surface runoff over agricultural lands under conservation tillage practices, with a reduction ranging from 46 to 67%. The field soil-water balance studies also indicated that more soil moisture was retained in plots under conservation tillage practices compared to plots under conventional tillage and hence the wider adoption of such a practice could influence the partitioning of rainfall across scales. The field based study was integrated into catchment process studies where a classical hydrometrical network was complemented with geophysical measurements (ERT) along catchment transects to determine the interaction of the surface and sub-surface water and the relative contribution of the subsurface water to catchment response. The study revealed that the shallow ground water contributes significantly, close to 75%, of the stream flows in the Potshini catchment, especially during the dry seasons, with the response of the shallow ground water being a function of both the rainfall intensity and daily total amount. The potential of integrating the catchment process studies with the larger river basin scale was explored through the evaporative term of the water balance by applying the Surface Energy Balance Algorithm for Land (SEBAL), a remote sensing methodology, to estimate total evaporation (ET) from the Moderate Imaging Spectroradiometer (MODIS) satellite images. This was validated with ground measurements from a Large Aperture Scintilometer (LAS) installed in the Potshini catchment. Good comparison was established between the remotely sensed estimates and LAS measurements with a deviation range of between -14 to 26% on discrete days, where the deviation was defined as the departure of the remotely sensed estimates of ET from the respective LAS measurements. The results from this study compare well with results from similar studies in other countries with different climatic conditions. Subsequently, the evaporative water use of various land uses in the upper Thukela river basin was assessed using MODIS images. Commercial forestry was identified to be the land use with a consistent and relatively high evaporative water use In the study area. High evaporation rates over water bodies were observed during the wet summer season when both the natural and man made water bodies were at full capacity. Nevertheless, it is recognized that the inherent low resolution ofthe MODIS images could have impacted on the SEBAL results. Finally, a conceptual framework, drawing the strengths of classical hydrometeorological networks, geophysical measurements, isotope tracers and remote sensing is suggested with the potential of enhancing our understanding and conceptualization of hydrological determinants across scales. The relevance of the framework to water resources management is highlighted through its application to the Potshini catchment and the Thukela river basin using results and findings from this study

Manufacturing of fermented goat milk with a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus in a controlled bioreactor

Aims: This work was undertaken to study the feasibility and the characteristics of a fermented product made of goat milk, using a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus under controlled conditions, and to determine their survival in the fermented milk during refrigerated storage. Methods and Results: Goat milk was inoculated with Lact. acidophilus and Bif. animalis mixed starter, fermented in a glass bioreactor with controlled temperature (37 C) and anaerobiosis, and monitored for growth and acidification. The fermented milk was then stored for 10 days under refrigeration, and monitored daily for starter microflora survival and pH changes. Lact. acidophilus viable counts reached a maximum of 7Æ1 · 108 colony-forming units (CFU) ml)1, and Bif. animalis a maximum of 6Æ3 · 107 CFU ml)1 by 20 h of fermentation. During refrigerated storage, both strains exhibited a good survival, with viable numbers remaining essentially constant throughout the experiment, whereas the pH of the fermented milk dropped slightly. Conclusions: Mixed cultures of Bif. animalis and Lact. acidophilus may be used to produce fermented goat milk with high counts of both probiotic strains. Significance and Impact of the Study: Goat milk fermented with Bif. animalis and Lact. acidophilus can be manufactured as an alternative probiotic dairy product

Detection and characterization of listeria monocytogenes in São Jorge (Portugal) cheese production

Listeria monocytogenes is a foodborne pathogen that can cause serious invasive disease in humans. Because human listeriosis cases have previously been linked to consumption of contaminated cheese, control of this pathogen throughout the cheese production chain is of particular concern. To understand the potential for L. monocytogenes transmission via Sa˜o Jorge cheese, a Portuguese artisanal cheese variety that bears a Protected Denomination of Origin classification, 357 raw milk, curd, natural whey starter, and cheese samples representative of the production chain of this cheese were collected over one year and tested for the presence of L. monocytogenes and selected physicochemical parameters. Although neither L. monocytogenes nor other Listeria spp. were detected in whey, curd, or cheese samples, 2 of the 105 raw milk samples analyzed were positive for L. monocytogenes. These 2 raw milk isolates represented a ribotype that has previously been linked to multiple human listeriosis outbreaks and cases elsewhere, indicating the potential of these isolates to cause human listeriosis. On average, physicochemical parameters of Sa˜o Jorge cheese ripened for 4 mo presented values that likely minimize the risk of L. monocytogenes outgrowth during ripening and storage (mean pH = 5.48; mean moisture = 37.79%; mean NaCl concentration = 4.73%). However, some cheese samples evaluated in this study were characterized by physicochemical parameters that may allow growth and survival of L. monocytogenes. Even though our results indicate that raw milk used for Sa˜o Jorge cheese manufacture as well as finished products is rarely contaminated with L. monocytogenes, continued efforts to control the presence of this pathogen in the Sa˜o Jorge cheese production chain are urged and are critical to ensure the safety of this product

Establishment of a catchment monitoring network through a participatory approach in a small rural catchment in South Africa

International audienceThe establishment of a catchment monitoring network is a process, from the inception of the idea to its implementation, the latter being the construction of relevant gauging structures and installation of the various instruments. It is useful that the local communities and other stakeholders are involved and participate in such a process as was realised during the establishment of the hydrological monitoring network in the Potshini catchment in the Bergville district in the KwaZulu-Natal Province in South Africa. The paper illustrates the participatory application of various methods and techniques for establishing a hydrological monitoring network, in a small rural inhabited catchment, to monitor hydrological processes at both field and catchment scale for research purposes in water resources management. The authors conclude that the participation of the local community and other stakeholders in catchment monitoring and instilling the sense of ownership and management of natural resources to the local communities needs to be encouraged at all times. Success stories in water resources management by local communities can be realized if such a process is integrated with other development plans in the catchment at all forums with due recognition of the social dynamics of the communities living in the catchment

Microbiological, biochemical and compositional changes during ripening of São Jorge – a raw milk cheese from the Azores (Portugal)

The microbial, compositional and biochemical profiles of São Jorge cheese (PDO) obtained from three distinct cheese plants, throughout the ripening period were determined. Fully ripened cheeses (i.e. by 130 days) contained a total of 3.1 107 CFU g 1 mesophilic bacteria, and a decrease in moisture content, concomitantly with an increase in salt content, was observed throughout the same time frame. The pH decreased until 30 days of ripening; thereafter, a slight increase was reported, up to 5.6 by the end of ripening. Urea-PAGE results showed extensive primary proteolysis, of both b-casein and as1-casein degraded at essentially similar rates; plasmin and chymosin accordingly appear to be active in the cheese curd. RP-HPLC profiles of water-soluble fractions showed minor differences between 1 and 130 day old cheeses, whereas equivalent profiles of 7% (v/v) ethanol-soluble fractions contained several peaks, indicative of a heterogeneous mixture of products of proteolysis, that evolved with time

Establishment of a catchment monitoring network through a participatory approach in a rural community in South Africa

The establishment of a catchment monitoring network is a process, from the inception of the idea to its implementation, the latter being the construction of relevant gauging structures and installation of the various instruments. It is useful that the local communities and other stakeholders are involved and participate in such a process, as was highlighted during the establishment of the hydrological monitoring network in the Potshini catchment in Bergville District in the KwaZulu-Natal Province, South Africa. The paper highlights the participatory establishment of a hydrological monitoring network in a small rural inhabited catchment, in line with the overall objective of the Smallholder System Innovations (SSI) research programme, to monitor hydrological processes at both field and catchment scale for water resources management research purposes. The engagement and participation of the Potshini community precipitated a learning opportunity for both the researchers and the local community on (i) the understanding of hydrological processes inherent in the catchment (ii) appreciating the inherent dynamics in establishing a catchment monitoring network in the midst of a community (iii) paradigm shift on how to engage different stakeholders at different levels of participation. The participatory engagement in the monitoring process led to appreciation and uptake of some of the research results by the Potshini community and ensured continued support from all stakeholders. This paper is of the view that the participation of the local community and other stakeholders in catchment monitoring and instilling a sense of ownership and management of natural resources to the local communities needs to be encouraged at all times. Success stories in water resources management by local communities can be realized if such a process is integrated with other development plans in the catchment at all forums, with due recognition of the social dynamics of the communities living in the catchment

The top 100 global water questions: Results of a scoping exercise

YesGlobal water security presents a complex problem for human societies and will become more acute as the impacts of climate change escalate. Water security connects the practical water and sanitation challenges of households to the dynamics of global hydroclimates and ecosystems in the Anthropocene. To ensure the successful deployment of attention and resources, it is necessary to identify the most pressing questions for water research. Here, we present the results of a scoping exercise conducted across the global water sector. More than 400 respondents submitted an excess of 4,000 potential questions. Drawing on expert analysis, we highlight 100 indicative research questions across six thematic domains: water and sanitation for human settlements; water and sanitation safety risk management; water security and scarcity; hydroclimate-ecosystem-Anthropocene dynamics; multi-level governance; and knowledge production. These questions offer an interdisciplinary and multi-scalar framework for guiding the nature and space of water research for the coming decades

The top 100 global water questions: Results of a scoping exercise

Global water security presents a complex problem for human societies and will become more acute as the impacts of climate change escalate. Water security connects the practical water and sanitation challenges of households to the dynamics of global hydroclimates and ecosystems in the Anthropocene. To ensure the successful deployment of attention and resources, it is necessary to identify the most pressing questions for water research. Here, we present the results of a scoping exercise conducted across the global water sector. More than 400 respondents submitted an excess of 4,000 potential questions. Drawing on expert analysis, we highlight 100 indicative research questions across six thematic domains: water and sanitation for human settlements; water and sanitation safety risk management; water security and scarcity; hydroclimate-ecosystem-Anthropocene dynamics; multi-level governance; and knowledge production. These questions offer an interdisciplinary and multi-scalar framework for guiding the nature and space of water research for the coming decades