Marine organisms often show deep genetic divergence between lineages that are characterized by shallow population structure. The distinction of historical and contemporary demographic forces in ...creating and maintaining these genetic patterns is crucial for management and conservation. In this study, we examined the genetic population structure of Bullia digitalis , a lecithotrophic sandy beach whelk that lacks a pelagic larval phase and is thus expected to show limited connectivity between populations. Mitochondrial (mt)DNA cytochrome c oxidase subunit I (COI; 540 bp, n = 214) and a reanalysis of allozyme data (14 loci, n = 735) among populations along the cool southeast Atlantic (west) and warm-temperate southwest Indian Ocean (south) coasts of southern Africa showed a strong phylogeographic break across Cape Point with mtDNA (Φ RT = 0.6, p < 0.001), but a weak break with allozymes ( F RT = 0.002, p = 0.004). MtDNA gene flow occurred asymmetrically from the west to the south coast. Although there was no mtDNA differentiation between populations on either side of that break (Φ SR = 0.0), there was weak but significant isolation by distance (IBD) among south coast samples (r 2 = 0.20, p = 0.039). In contrast, significant allozyme differentiation was detected on small spatial scales but without overall IBD. MtDNA mismatch analysis indicated a recent range expansion, suggesting historic population expansions, most likely during periods of lower sea levels and greater habitat continuity along southern African shores. Thus, the apparent mtDNA connectivity among populations of beach whelks likely reflects historic, rather than contemporary, gene flow.
Bio-monitoring of pollutants in long-lived animals such as sea turtles is an important tool in ecotoxicology. We present the first report on metallic elements in sea turtle eggs from the Indian ...Ocean. Eggs of the leatherback and loggerhead turtle that breed on the Indian Ocean coast of South Africa were analysed for 30 elements. The eggshells and egg contents of the loggerhead turtle, the smaller of the two species, had higher or significantly higher concentrations than leatherbacks, except for strontium - the reason is unknown. Elemental concentrations in eggshells and contents were the same or lower compared with other studies. The differences in concentrations in the egg contents and eggshells between the two species are likely due to different trophic levels, migration patterns, life histories, age, and growth, as well as differences in pollution sources and the uptake, retention and elimination characteristics of the different elements by the different species. We found no congruence between patterns in eggshells and corresponding egg contents, for both species. However, eggshells and egg contents showed congruence between species. The lack of congruence between eggshells and contents within each species precludes using eggshell concentrations as a proxy for egg content concentrations. Copper, strontium, and selenium occurred at concentrations higher than available toxic reverence values. Further research is warranted, including the analyses of POPs, as well as possible deme discrimination based on compositional pattern differences. Turtles serve as ‘active samplers’ returning to the same location to breed–something that is not practical with marine mammals or elasmobranchs.
Display omitted
•First report of metals and metalloids in sea turtle eggs from the Indian Ocean.•Loggerhead and leatherback eggs collected from the South African coast, and analysed.•Life-history differences accounted for much of the differences in concentrations.•Cu and Sr exceeded levels of concern, but no indication of reproductive failure.•Eggshells cannot be used as proxy for egg contents - no elemental congruence.
Abstract
Sea turtles are long-lived migratory species that are sensitive to anthropogenic impacts. Their condition reflects that of marine ecosystems and can serve as an indicator for environmental ...monitoring. However, evaluating body condition parameters, as a proxy for health, is challenging and often overlooked. The purpose of this study was to validate a straightforward method for assessing the body condition of nesting loggerhead sea turtles (
Caretta caretta
), and to investigate whether body condition was correlated with epibiont loading. To achieve this, 60 nesting loggerhead sea turtles were sampled and categorized into five body conditions ranging from very poor to very good. Injuries, skin deformities and plastron shape were used for this classification. Epibionts were collected from the same turtles and identified, with species richness, diversity, community structure and barnacle loading compared among body conditions. Epibiont communities were correlated with body condition as both species richness and abundance increased with a decline in turtle body condition. Barnacle epibionts showed great variation among different body conditions, having significantly higher numbers on turtles in poor condition. All parameters in this study showed similar distinctive relationships with body condition of loggerhead turtles from poor to very good body condition. The body condition index used in this study can be applied readily and, along with barnacle counts, can provide basic baseline information on turtle health.
The increased necessity to obtain energy from other sources than conventional fossil fuels has led to the growing interest in solar energy. The problem with the proposed technology is that it can ...only provide power during the day and therefore requires some sort of storage system, if power is to be supplied throughout the day and night. A number of storage systems exist, but the one of particular interest is packed rock beds. Discrete Element Models (DEM) of rock beds were developed through both experimental and numerical procedures, by conducting a series of sensitivity and calibration studies. Through these procedures, a set of microproperties could be determined to accurately model the rock particles. The properties were verified by modelling the discharge from a hopper with three different opening widths. Further, the research focused on the potential of constructing self-supporting tunnels within the rock beds in order to improve the air flow through the bed by minimizing the pressure drop. Horizontal and vertical tunnels were investigated, each with different diameters. It was observed that if the appropriate steps were followed, stable self-supporting tunnels could be formed using particles of different scale.
Discrete Element Models of rock beds were developed through experimental and numerical procedures, sensitivity and calibration tests. The potential of constructing self-supporting tunnels within rock beds to improve the air flow through the bed was investigated. It was observed that stable self-supporting tunnels could be formed using particles of different scale. Display omitted
•The microproperties used in the Discrete Element Method (DEM) is calibrated.•The properties are then validated by modelling the discharge from a hopper.•The calibrated model is used to model packed rock beds for thermal energy storage.•Horizontal and vertical self-sustaining tunnels can be formed inside the rock bed.•Particles of different size scale are needed to form stable tunnels.
Editorial Mangayi, L.; Nel, R. Nel
Missionalia,
06/2017, Letnik:
45, Številka:
2
Journal Article
Recenzirano
As we commemorate 500 years of Reformation many Christian theology disciplines and institutions have been reflecting on the gains or losses realised thus far in relation to the contemporary world we ...live in. There seems to be consensus in the reflections carried out by these disciplines and institutions that Reformation was not just a moment in history. It is rather a movement which is ongoing and which fosters an ethos to be engraved in theology. It inculcates a reflexive culture, which should continue to ask what sound Christian dogma stands for and whether the church and its ministries including mission have kept in step with this dogma.
Delineating spatial boundaries that accurately encompass complex, often cryptic, life histories of highly migratory marine megafauna can be a significant conservation challenge. For example, marine ...turtles range across vast ocean basins and coastal areas, thus complicating the evaluation of relative impacts of multiple overlapping threats and the creation of coherent conservation strategies. To address these challenges, spatially explicit ‘regional management units’ (RMUs) were developed in 2010 for all marine turtle species, globally. RMUs were intended to provide a consistent framework that organizes conspecific assemblages into units above the level of nesting rookeries and genetic stocks, but below the species level, within regional entities that may share demographic trajectories because they experience similar environmental conditions and other factors. From their initial conception, RMUs were intended to be periodically revised using new information about marine turtle distributions, life history, habitat use patterns, and population structure. Here, we describe the process used to update the 2010 RMU framework by incorporating newly published information and inputs from global marine turtle experts who are members of the IUCN Marine Turtle Specialist Group. A total of 48 RMUs for 6 of 7 marine turtle species and 166 distinct genetic stocks for all 7 species are presented herein. The updated RMU framework reflects a significant advance in knowledge of marine turtle biology and biogeography, and it provides improved clarity about the RMU concept and its potential applications. All RMU products have been made open access to support research and conservation initiatives worldwide.
Loggerhead sea turtles (
Caretta caretta
) occupy an array of marine habitats throughout their lives and understanding how this threatened species utilizes these habitats can help guide conservation ...efforts. This study used a combination of isotopic analysis (δ
13
C; δ
15
N) of turtle epidermis and epibiotic community composition to examine habitat-use patterns of nesting loggerheads from the South West Indian Ocean and related these to turtle body condition. First, we identified two foraging groups using relative changes in the turtle’s epidermis δ
13
C isotope values (of 170 individuals). Second, we show that epibiont communities (of 80 turtles) differed significantly between the two foraging groups, with oceanic/pelagic and neritic/benthic species occurring in higher abundances on turtles with depleted and enriched δ
13
C values, respectively. The complementary evidence from isotope and epibiont data thus indicates that nesting loggerheads of this population exhibit a bimodal foraging strategy. The relatively high variability in δ
13
C and δ
15
N values of the turtles’ tissue showed that they have a broad isotopic niche. While isotopic niches overlapped among turtles with different body conditions, very healthy individuals had a significantly narrower isotopic niche width than those in poorer condition. This suggests that turtles in very good condition are food specialists, and individuals with suboptimal body conditions utilise a wider range of food items and are more generalist foragers. These results show the value of using a combination of stable isotopes and epibiont communities as cost-effective tools that can be applied effectively to derive information on habitat-use patterns of migratory species.
INTRODUCTION: Planning and implementation of oral health education is of more value when oral health-related knowledge, attitudes and practices (KAP) are known AIM: To assess and describe oral ...health-related KAP of adult patients in the Mangaung Metropolitan Municipality using the theory of planned behaviour METHODS: A quantitative descriptive design was used and data were collected from a sample of 207 adult oral health patients using a questionnaire based on the Theory of Planned Behaviour (TPB RESULTS: Positive responses by participants towards oral-related KAP were regarded as strengthening oral health-related practices. Oral health-related knowledge as reflected by participants' behavioural beliefs (93.7%), normative beliefs (81.1%), subjective norms (70%) and perceived behavioural control (71.9%) strengthened oral health behaviours positively. Participants' control beliefs did not strengthen oral health practices. Participants' attitudes (62.3%),intention (98.5%), actual behavioural control (99%) and behaviour (95.1%) strengthened oral health-related practices Adult patients generally portrayed behavioural beliefs, normative beliefs, subjective norms and perceived behavioural control that strengthened oral health behaviours positively. CONCLUSIONS: Understanding oral health-related KAP of adult patients would assist role players in the health sector to plan evidence based oral health education. Healthcare workers should be sensitive to the KAP of adult patients receiving oral health-related care
Although published literature regarding the 5 species of marine turtle found along the continental African east coast has grown substantially over the last decades, a comprehensive synthesis of their ...status and ecology is lacking. Using a mixed methods approach, which combined an exhaustive literature review and expert elicitation, we assessed the distribution and magnitude of nesting, foraging areas, connectivity, and anthropogenic threats for these species in Somalia, Kenya, Tanzania, Mozambique, and South Africa. A complex pattern of nesting sites, foraging areas, and migration pathways emerged that identified areas of high importance in all 5 countries, although significant data gaps remain, especially for Somalia. Illegal take, bycatch, and loss of foraging and nesting habitat were identified as the most serious anthropogenic threats. Although these threats are broadly similar along most of the coast, robust data that enable quantification of the impacts are scarce. Experts identified regional strengths and opportunities, as well as impediments to turtle conservation. Topics such as legislation and enforcement, collaboration, local stakeholders, and funding are discussed, and future directions suggested. Given the projected growth in human population along the continental African east coast and expected accompanying development, anthropogenic pressures on turtle populations are set to increase. Stronger regional collaboration and coordination within conservation and research efforts are needed if current and future challenges are to be tackled effectively.
South Africa has a long history of engagement in citizen science (CS), particularly marine CS. This review examines the contributions made by marine CS, from the 1930s through to the current era, ...where websites, social media and mobile apps provide a wide range of opportunities. Largescale marine CS projects, such as the Oceanographic Research Institute's Cooperative Fish Tagging Project, have made enormous contributions to marine scientific research. Individual citizen scientists have also made considerable contributions, particularly in taxonomy and the publication of field guides. Marine CS has also contributed towards the popularisation of science and improved scientific literacy through the active engagement of many citizens. These benefits align well with the visions of policies that currently guide the South African marine research agenda. However, marine CS in the developing world is not without challenges, and practitioners should be cognisant of the time and effort required to initiate and maintain viable CS initiatives. Especially, long-term successful CS projects depend on secure, ongoing funding, institutional support and enthusiastic champions. Participation by almost exclusively the urban and middle-class sectors of society is also of concern. These challenges can be addressed through stakeholder-inclusive planning, development of novel methods that engage with broader sectors of society, and regular critical evaluations of CS projects. Where global projects on the intended taxa/subject of study already exist, it may also be preferable to enter into collaborative data-sharing agreements with these to reduce operational costs and avoid duplication.
PDF
