176 research outputs found
The Karyotype of Blainville's Beaked Whale, Mesoplodon densirostris
No full textThe karyotype of the Odontocete whale, Mesoplodon densirostris, has not been previously reported. The chromosome number is determined to be 2n = 42, and the karyotype is presented using G-, C-, and nucleolar organizer region (NOR) banding. The findings include NOR regions on 2 chromosomes, regions of heterochromatic variation, a large block of heterochromatin on the X chromosome, and a relatively large Y chromosome. The karyotype is compared to published karyograms of 2 other species of Mesoplodon.No Full Tex
Twee Bybelse Verhale van Abraham H. De Vries
No full textAbraham de Vries is not so much known as the author of Biblical stories, but two stories can be pointed out very clearly as belonging to this category. These stories are "Skoenmaker diepe water" from Volmoed se gasie and "Die verdeling van die kind” from Vliegoog.
The first story, "Skoenmaker diepe water”, refers to Matthew 14:22 - 32 in which Jesus walks on water. In this story the fairy tale given appears at the first level, and the religious motif on the second level. The main character, Vel Binneman, is clearly depicted in the story as being the true believer.
“Die verdeling van die kind” also has a Biblical background, and then Herod's infanticide in Bethlehem of which we read in Matthew 2:16 as well as the crucifixion of Christ. In the story It is not only the Biblical motif that is dealt with, but there is a strong Palestinian and New Testament aura. "Die verdeling van die kind” can, with the data at our disposal, be interpreted as a new crucifixion, and the story in fact does become an illustration of God’s redeeming grace
Co-ownership shares in condominium – A comparison across jurisdictions and standards
No full textCondominium is one of the prevalent forms of three- dimensional (3D) property rights (Paulsson, 2007, p. 32). The condominium concept common to a number of jurisdictions consists of three elements: (a) individual ownership of an apartment, (b) co-ownership (joint ownership) of the land and the common parts of the building, and (c) membership of an incorporated or unincorporated owners' association (van der Merwe, 2015, p. 5). The ownership shares of condominium unit owners in the common property are here referred to as co-ownership shares; yet, alternative terms include ownership fraction, condominium share, participation quota, share value, and unit entitlement. The co-ownership share determines the proportional contribution to the common expenses and the share of common profits, as well as the voting power of each condominium unit owner in the administration of the condominium. The most common approaches to the determination of the co-ownership shares are based on equality, relative size or relative value of each condominium unit, or a combination of such (van der Merwe, 1994, p. 57-58). The literature presents detailed descriptions and comparative analysis related to condominium systems in different jurisdictions (e.g. van der Merwe, 2016; 2015; Paulsson, 2007; EUI, 2005; UNECE, 2005); however, the technical and procedural aspects related to the allotment of co-ownership shares still need to be further investigated. This paper aims to compare methods and procedures applied for the allotment of co-ownership shares of condominium systems in the following seven jurisdictions; Denmark, Germany, South Africa, Sweden, Switzerland, the Netherlands, and Turkey. Also, international geographic information standards are analyzed to assess the extent to which they facilitate allocation of co-ownership shares. The main purpose is to clarify the legal provisions and methodologies related to the determination of co-ownership shares in national condominium systems and bring new insights to countries, which are trying to revise their national provisions for fairer implementations
Adaption and application of cell-based bioassays to whole-water samples
No full textThe increasing presence of contaminants of emerging concern in wastewater and their potential environmental risks require improved monitoring and analysis methods. Direct toxicity assessment (DTA) using bioassays can complement chemical analysis of wastewater discharge, but traditional in vivo tests have ethical considerations and are expensive, low-throughput, and limited to apical endpoints (mortality, reproduction, development, and growth). In vitro bioassays offer an alternative approach that is cheaper, faster, and more ethical, and can provide higher sensitivity for some environmentally relevant endpoints. This study explores the potential benefits of using whole water samples of wastewater and environmental surface water instead of traditional solid phase extraction (SPE) methods for in vitro bioassays testing. Whole water samples produced a stronger response in most bioassays, likely due to the loss or alteration of contaminants during SPE sample extraction. In addition, there was no notable difference in results for most bioassays after freezing whole water samples, which allows for increased flexibility in testing timelines and cost savings. These findings highlight the potential advantages of using whole water samples in DTA and provide a framework for future research in this area.Full Tex
A comparative analysis of the karyotypes of three dolphins – Tursiops truncatus Montagu, 1821, Tursiops australis Charlton-Robb et al., 2011, and Grampus griseus Cuvier, 1812
No full textThe aim of this study is to produce G-banded karyotypes of three dolphin species, Tursiops truncatus Montagu, 1821, Tursiops australis Charlton-Robb et al., 2011, and Grampus griseus Cuvier, 1812, and to determine if any differences between the species can be observed. Monolayer skin cultures were established and processed for chromosome study by trypsin banding. The results indicate that the three species here investigated have the same diploid number (2n = 44) and very similar gross chromosome morphology, however G-banding allows distinction between each species. Chromosome 1 in G. griseus is significantly different from the other 2 species, and chromosome 2 in T. australis is subtly different from the other 2 species. This result is of potential significance in taxonomic studies, and can provide an unequivocal answer in the assessment of suspected hybrids between these species
Optimisation of an automated high-throughput micronucleus (HiTMiN) assay to measure genotoxicity of environmental contaminants
No full textAnthropogenic contaminants can have a variety of adverse effects on exposed organisms, including genotoxicity in the form of DNA damage. One of the most commonly used methods to evaluate genotoxicity in exposed organisms is the micronucleus (MN) assay. It provides an efficient assessment of chromosomal impairment due to either chromosomal rupture or mis-segregation during mitosis. However, evaluating chromosomal damage in the MN assay through manual microscopy is a highly time-consuming and somewhat subjective process. High-throughput evaluation with automated image analysis could reduce subjectivity and increase accuracy and throughput. In this study, we optimised and streamlined the HiTMiN assay, adapting the MN assay to a miniaturised, 96-well plate format with reduced steps, and applied it to both primary cells from green turtle fibroblasts (GT12s-p) and a freshwater fish hepatoma cell line (PLHC-1). Image analysis using both commercial (Columbus) and freely available (CellProfiler) software automated the scoring of MN, with improved precision and drastically reduced time compared to manual scoring and other available protocols. The assay was validated through exposure to two inorganic (chromium and cobalt) and one organic (the herbicide metolachlor) compounds, which are genotoxicants of concern in the marine environment. All compounds tested induced MN formation below cytotoxic concentrations. The HiTMiN assay presented here greatly increases the suitability of the MN assay as a quick, affordable, sensitive and accurate assay to measure genotoxicity of environmental samples in different cell lines.No Full Tex
Global oxygen isoscapes for barnacle shells: Application for tracing movement in oceans
No full textIt is helpful to understand the movement of animals and objects to inform species conservation and broader environmental management (e.g. by identifying the origin of marine debris). Tagging techniques are limited to investigations of future movement (e.g. after a tag has been applied), with no ability to understand where an animal or object has come from prior to encounter. However, studies that apply chemical techniques are able to address questions about historical movement prior to encounter, particularly through the analysis of stable isotopes from the tissues of migrating animals, or from barnacle shells that attach to migrating hosts. Barnacle shell isotope analysis is a promising technique that could provide a new understanding of the ecology of migrating marine fauna, or additionally the origin of marine debris. Here we use global datasets to assess the applicability of barnacle shell isotope techniques for identifying the origin and travel pathways of animals and objects that carry hitchhiking barnacles. We present the first global isoscapes for barnacle shell calcite, using these to identify areas that are likely to offer the finest spatial resolution for this application. We further demonstrate how isoscapes can be applied to back-trace animal migrations using real-world migration case studies of sea turtles and whales. We demonstrate that coastal areas and mid-latitude oceanic regions are likely to offer the best spatial resolution, and that migration pathways are able to be identified from successive barnacle shell samples. We expect that this work will allow for more efficient and precise future applications of barnacle shell isotope analyses to trace the movement and origin of barnacle hosts through marine waters.No Full Tex
Pelagic and coastal green turtles (Chelonia mydas) experience differences in chemical exposure and effect
No full textGreen turtles foraging in coastal areas are exposed to land-based chemical pollutants that accumulate in the habitats to which they show high site fidelity. However, prior to coastal recruitment, they may be exposed to a different range of chemical threats. The recent development of species-specific in vitro bioassays for marine turtles allows for an effect-based assessment of toxicological endpoints. Blood was collected from green turtles of two life-stages, ‘recent recruits’ and ‘coastal residents’, in Hervey Bay and Moreton Bay. Organic contaminants were extracted from blood using the QuEChERS method, and cytotoxicity of the extracts measured in green turtle skin cells. Although not statistically significant, extracts from ‘coastal residents’ exhibited greater mean toxicity compared to ‘recent recruits’, possibly indicative of increased chemical accumulation from coastal habitat exposure. The bioassay results also indicated that turtles foraging in Hervey Bay are at greater risk of chemical exposure than those foraging in Moreton Bay.No Full Tex
Assessing the impact of chemical exposure on the health of endangered sea turtles through toxicokinetics and toxicodynamics
No full textThe green sea turtle, Chelonia mydas, spends a considerable part of its life in coastal waters foraging on seagrass and/or algae, which brings it close to anthropogenic pollutant sources. Elevated concentrations of chemical contaminants from urban, industrial and agricultural run-off accumulate in coastal environments. These pollutants have the potential to cause serious harm to C. mydas populations. However, exposure and toxicity data are challenging to obtain for free-ranging, protected wildlife species like C. mydas. Furthermore, a lack of quantitative tools linking long-term external contaminant exposure, the uptake and tissue distribution of chemicals (toxicokinetics), and the biological pathway perturbations related to adverse health outcomes (toxicodynamics) hamper efforts by scientists and policymakers to quantify the risk of pollutants adversely affecting C. mydas
health. Changes in C. mydas population abundance, in turn, may affect the marine seagrass ecosystems, which, by extension, could potentially also impact human health and animals that rely on seagrass habitats.
The present thesis provided the means to research the hypothesis that land-based contaminants adversely impact the health of Australia’s resident green turtle populations. The following chapters in this thesis investigate the validity of this hypothesis. Valuable experimental toxicokinetic and toxicodynamic data are collected and described in Chapters 2 and 3. Chapter 4 used data from Chapter 3 to develop tools to confirm the initial hypothesis. Overall, this thesis describes the development of tools to aid risk assessors and policymakers in setting safe chemical exposure levels for green sea populations.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Environment and ScScience, Environment, Engineering and TechnologyFull Tex
The combined and interactive effects of multiple stressors on Great Barrier Reef ecosystems
No full textCoastal ecosystems are under threat by an increasing number of natural and anthropogenic stressors. These stressors co-occur in countless combinations, raising questions in the scientific community about their combined and/or interactive effects on individuals, populations and ecosystems. Environmental management of multiple stressors is challenging, as the governance of stressors are still largely based on individual effects, despite growing evidence of interactive effects in coastal ecosystems. As a result, the field of multiple stressor research is rapidly expanding to better understand, predict and manage stressor interactions.
This thesis aims to address questions surrounding deteriorating water quality, as an indication of ecosystem health, of the Great Barrier Reef (GBR). Land-based runoff has been identified as the greatest contributor to poor water quality in inshore marine ecosystems, such as the GBR. The three main water quality pollutants common to the GBR include pesticides, excess nutrients and suspended sediments. These pollutants originate from coastal development and agricultural practices and are transported to receiving waters via flood plumes. Following high rainfall during the Queensland wet season, GBR ecosystems are simultaneously exposed to high concentrations of pesticides, nutrients and sediments. This thesis presents a collection of related chapters that assess the effects of these three water quality stressors on coastal ecosystems.Thesis (PhD Doctorate)Doctor of Philosophy (PhD)School of Environment and ScScience, Environment, Engineering and TechnologyFull Tex
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