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1
Gounden, Rivoni, Suveshnee Munien, Dinolen Gounden e Ntwandamela Perry. "Visitor Profiles of Coastal and Marine Tourism Sites in the Eastern Cape, South Africa". African Journal of Hospitality, Tourism and Leisure, n. 9(6) (15 dicembre 2020): 1060–75. http://dx.doi.org/10.46222/ajhtl.19770720-68.
Testo completoAbstract (sommario):
Current research on Coastal and Marine Tourism (CTM) in South Africa focuses on two main coastal tourism provinces (KwaZulu-Natal and Western Cape) as well as specific CMT activities such as whale watching and shark cage diving. This study, therefore, contributes to the body of knowledge on CMT by focusing on the Eastern Cape and undertaking a provincial level analysis. Coastal and Marine Tourism location visitor profiles in terms of socio-economic profile, types of CMT visitors, types of CMT activities participated and future interest in the Eastern Cape, South Africa. CMT encompasses activities and resources in and near coastal and marine areas that attract visitors who participate in a range of active and passive business, adventure, leisure and recreational activities that generate socio-economic and environmental benefits. A quantitative approach is adopted, drawing on 700 visitor surveys that were conducted at purposively selected CMT locations in the Eastern Cape. Visitors were from a range of socio-economic backgrounds. There were high levels of participation in CMT activities, especially coastal leisure and recreational activities. Results indicate increased CMT location visitation demand. From a sustainability and responsible tourism perspective, understanding who visits CMT sites assists in ensuring effective planning to manage demand and protect/ conserve coastal and marine resources.
2
Smale, M. J. "The feeding biology of four predatory reef fishes off the south-eastern Cape coast, South Africa". South African Journal of Zoology 21, n. 2 (gennaio 1986): 111–30. http://dx.doi.org/10.1080/02541858.1986.11447968.
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Adams, Luther A., Gavin W. Maneveldt, Andrew Green, Natasha Karenyi, Denham Parker, Toufiek Samaai e Sven Kerwath. "Rhodolith Bed Discovered off the South African Coast". Diversity 12, n. 4 (27 marzo 2020): 125. http://dx.doi.org/10.3390/d12040125.
Testo completoAbstract (sommario):
Rhodolith beds have not previously been recorded in South Africa. A multidisciplinary research effort used remote sampling tools to survey the historically unexplored continental shelf off the Eastern Cape coast of South Africa. A rhodolith bed, bearing both living and dead non-geniculate coralline red algae, was discovered in the 30–65 m depth range off the Kei River mouth in the newly proclaimed Amathole Offshore Marine Protected Area. Some of the rhodolith forming coralline algal specimens were identified as belonging to at least three genera based on their morphology and anatomy, namely, Lithophyllum, Lithothamnion and a non-descript genus. Rhodolith mean mass and diameter were 44.85 g ± 34.22 g and 41.28 mm ± 10.67 mm (N = 13), respectively. Remotely operated vehicle (ROV) imagery revealed a suite of epibenthic red macroalgae associated with the rhodolith bed. Taxonomy, vertical structure and distribution of rhodoliths in South Africa require further investigation.
4
Alt, Katharina G., Thomas Kuhn, Julian Münster, Regina Klapper, Judith Kochmann e Sven Klimpel. "Mesopredatory fishes from the subtropical upwelling region off NW-Africa characterised by their parasite fauna". PeerJ 6 (8 agosto 2018): e5339. http://dx.doi.org/10.7717/peerj.5339.
Testo completoAbstract (sommario):
Eastern boundary upwelling provides the conditions for high marine productivity in the Canary Current System off NW-Africa. Despite its considerable importance to fisheries, knowledge on this marine ecosystem is only limited. Here, parasites were used as indicators to gain insight into the host ecology and food web of two pelagic fish species, the commercially important species Trichiurus lepturus Linnaeus, 1758, and Nealotus tripes Johnson, 1865. Fish specimens of T. lepturus (n = 104) and N. tripes (n = 91), sampled from the Canary Current System off the Senegalese coast and Cape Verde Islands, were examined, collecting data on their biometrics, diet and parasitisation. In this study, the first parasitological data on N. tripes are presented. T. lepturus mainly preyed on small pelagic Crustacea and the diet of N. tripes was dominated by small mesopelagic Teleostei. Both host species were infested by mostly generalist parasites. The parasite fauna of T. lepturus consisted of at least nine different species belonging to six taxonomic groups, with a less diverse fauna of ectoparasites and cestodes in comparison to studies in other coastal ecosystems (Brazil Current and Kuriosho Current). The zoonotic nematode Anisakis pegreffii occurred in 23% of the samples and could pose a risk regarding food safety. The parasite fauna of N. tripes was composed of at least thirteen species from seven different taxonomic groups. Its most common parasites were digenean ovigerous metacercariae, larval cestodes and a monogenean species (Diclidophoridae). The observed patterns of parasitisation in both host species indicate their trophic relationships and are typical for mesopredators from the subtropical epi- and mesopelagic. The parasite fauna, containing few dominant species with a high abundance, represents the typical species composition of an eastern boundary upwelling ecosystem.
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Whitfield, Alan K., e Paula Pattrick. "Habitat type and nursery function for coastal marine fish species, with emphasis on the Eastern Cape region, South Africa". Estuarine, Coastal and Shelf Science 160 (luglio 2015): 49–59. http://dx.doi.org/10.1016/j.ecss.2015.04.002.
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Marais, J. F. K. "Body composition of ten marine migrants and one freshwater fish species caught in estuaries of the Eastern Cape, South Africa". South African Journal of Marine Science 9, n. 1 (giugno 1990): 135–40. http://dx.doi.org/10.2989/025776190784378844.
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Fatoki, O. S., e O. R. Awofolu. "Levels of Organochlorine Pesticide Residues in Marine-, Surface-, Ground- and Drinking Waters from the Eastern Cape Province of South Africa". Journal of Environmental Science and Health, Part B 39, n. 1 (gennaio 2004): 101–14. http://dx.doi.org/10.1081/pfc-120027442.
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Costalago, D., Y. Kisten, C. Clemmesen e NA Strydom. "Growth and nutritional condition of anchovy larvae on the west and southeast coasts of South Africa". Marine Ecology Progress Series 644 (25 giugno 2020): 119–28. http://dx.doi.org/10.3354/meps13345.
Testo completoAbstract (sommario):
Cape anchovy Engraulis encrasicolus is an ecologically and economically important pelagic fish species occurring along the coast of South Africa. A recent eastward shift in Cape anchovy distribution indicates that environmental conditions are becoming more favorable for the species on the east coast. This shift is particularly important in the sheltered Algoa Bay region, a nursery area for fish larvae. However, the relatively low productivity of the Agulhas Current Large Marine Ecosystem on the eastern coast of South Africa may result in an anchovy population in poorer nutritional condition and with slower growth rates than the west coast population. Using otolith and nucleic acid analyses, the growth rates of anchovy larvae from the western and southeastern coasts of South Africa were compared. The otolith analysis results indicated that, at any given age, individual growth rates for anchovy larvae were higher on the southeast coast than on the west coast. The RNA:DNA values also indicated that instantaneous growth rates of anchovy larvae were higher in Algoa Bay than on the west coast. At the time of sampling, chlorophyll and zooplankton productivity were higher at sampling sites in Algoa Bay than sites on the west coast, potentially due to favorable oceanographic features in the bay. As such, the results suggest that Algoa Bay is a suitable and potentially favorable nursery area for the early stages of anchovy, highlighting the importance of separate management of the southeast coast region in a changing world.
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Dupont, L. M., T. Caley, J. H. Kim, I. Castaneda, B. Malaizé e J. Giraudeau. "Glacial-interglacial vegetation dynamics in south eastern Africa depend on sea surface temperature variations in the west Indian Ocean". Climate of the Past Discussions 7, n. 4 (6 luglio 2011): 2261–96. http://dx.doi.org/10.5194/cpd-7-2261-2011.
Testo completoAbstract (sommario):
Abstract. Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between Indian and Atlantic Ocean. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ~120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (down till 342 ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including elements with affinity to the Cape Flora) for the last glacial as well as for other glacial periods of the past 300 ka.
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Chima, Priscilla, Christopher Baiyegunhi, Kuiwu Liu e Oswald Gwavava. "Petrography, modal composition and tectonic provenance of some selected sandstones from the Molteno, Elliot and Clarens Formations, Karoo Supergroup, in the Eastern Cape Province, South Africa". Open Geosciences 10, n. 1 (20 dicembre 2018): 821–33. http://dx.doi.org/10.1515/geo-2018-0064.
Testo completoAbstract (sommario):
Abstract The Late Triassic - Early Jurassic non marine clastic sediments of the Molteno, Elliot and Clarens Formations were studied to deduce their mineralogy and tectonic provenance. The study is based on road-cut exposures of the formations in the Eastern Cape Province of South Africa. Petrographic studies based on quantitative analysis of the detrital minerals shows that the clastic sediments (mostly sandstones) are predominantly made up of quartz, feldspars, and metamorphic and igneous rock fragments. Among the main detrital framework grains, quartz constitutes about 62-91%, feldspar 6-24% and 3-19% of lithic fragments. The sandstones can be classified as both sublitharenite and subarkose. Although, most of the sandstones (> 70 %) plotted in the sub-litharenite field. Petrographic and XRD analyses revealed that the sandstones originated from granitic and metamorphic rock sources. The QFL (Quartz-feldspar-lithic fragments) ternary diagrams indicate that the sandstones were derived from recycled or quartzose source rocks reflecting a craton interior or transitional continental setting which probably came from the Cape Fold Belt. This possibly revealed that most of the sandstones might have been derived as a result of weathering and erosion of igneous and metamorphic rocks in the Cape Supergroup. The study has revealed the depositional environments, and provide a basis for the description and interpretation of the sedimentology of the Molteno, Elliot and Clarens Formations.
11
Stone, Philip. "Geology reviewed for the Falkland Islands and their offshore sedimentary basins, South Atlantic Ocean". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 106, n. 2 (giugno 2015): 115–43. http://dx.doi.org/10.1017/s1755691016000049.
Testo completoAbstract (sommario):
ABSTRACTThe position of the Falkland Islands adjacent to the South American continental margin belies the close association of their geology with that of South Africa. A Mesoproterozoic basement is unconformably overlain by a Silurian to Devonian succession of fluvial to neritic and shallow marine, siliciclastic strata. This is disconformably succeeded by a largely Permian succession that, near its base, includes a glacigenic diamictite and, thence, passes upwards into a succession of deltaic and lacustrine strata. The lithological succession and the character of its deformation bear striking similarities to the Cape Fold Belt and Karoo retroarc foreland basin. Swarms of Early Jurassic dykes were coeval with the Karoo magmatism and the initial break-up of Gondwana; Early Cretaceous dykes were intruded during the opening of the South Atlantic Ocean. Offshore sedimentary basins surrounding the archipelago contain Late Jurassic to Palaeogene successions and are currently the focus of hydrocarbon exploration. Best known is the North Falkland Basin, a classic failed rift. To the SE, the passive margin, Falkland Plateau Basin may also be rift-controlled, whilst the South Falkland Basin is a foreland basin created at the boundary of the South American and Scotia plates. The role of the Falkland Islands during the breakup of Gondwana remains controversial. Compelling evidence from the onshore geology favours rotation of an independent microplate from an original position adjacent to the Eastern Cape, South Africa. Alternative interpretations, justified largely from offshore geology, favour extension of the Falkland Plateau as a fixed promontory from the South American margin.
12
Baiyegunhi, Christopher, e Kuiwu Liu. "Sedimentary facies, stratigraphy, and depositional environments of the Ecca Group, Karoo Supergroup in the Eastern Cape Province of South Africa". Open Geosciences 13, n. 1 (1 gennaio 2021): 748–81. http://dx.doi.org/10.1515/geo-2020-0256.
Testo completoAbstract (sommario):
Abstract The stratigraphy of the Ecca Group has been subdivided into the Prince Albert, Whitehill, Collingham, Ripon, and Fort Brown Formations in the Eastern Cape Province, South Africa. In this article, we present detailed stratigraphic and facies analyses of borehole data and road-cut exposures of the Ecca Group along regional roads R67 (Ecca Pass), R344 (Grahamstown-Adelaide), R350 (Kirkwood-Somerset East), and national roads N2 (Grahamstown-Peddie) and N10 (Paterson-Cookhouse). Facies analysis of the Ecca Group in the study area was performed to deduce their depositional environments. Based on the lithological and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham, and Fort Brown Formations is now subdivided into two informal members each, while the Ripon Formation is subdivided into three members. A total of twelve lithofacies were identified in the Ecca Group and were further grouped into seven distinct facies associations (FAs), namely: Laminated to thin-bedded black-greyish shale and mudstones (FA 1); Laminated black-greyish shale and interbedded chert (FA 2); Mudstone rhythmite and thin beds of tuff alternation (FA 3); Thin to thick-bedded sandstone and mudstone intercalation (FA 4); Medium to thick-bedded dark-grey shale (FA 5); Alternated thin to medium-bedded sandstone and mudstone (FA 6); and Varved mudstone rhythmite and sandstone intercalation (FA 7). The FAs revealed gradually change of sea-level from deep marine (FA 1, FA 2, FA 3 and FA 4, FA 5, and FA 6) to prodelta environment (FA 7). This implies that the main Karoo Basin was gradually filling up with Ecca sediments, resulting in the gradual shallowing up of the water depth of the depositional basin.
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Reddy, Poogendri, Nicola C. James, Alan K. Whitfield e Paul D. Cowley. "Marine Connectivity and Fish Length Frequencies of Selected Species in Two Adjacent Temporarily Open/Closed Estuaries in the Eastern Cape Province, South Africa". African Zoology 46, n. 2 (ottobre 2011): 239–45. http://dx.doi.org/10.3377/004.046.0204.
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Reddy, Poogendri, Nicola C. James, Alan K. Whitfield e Paul D. Cowley. "Marine connectivity and fish length frequencies of selected species in two adjacent temporarily open/closed estuaries in the Eastern Cape Province, South Africa". African Zoology 46, n. 2 (ottobre 2011): 239–45. http://dx.doi.org/10.1080/15627020.2011.11407498.
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Mann, BQ, L. Celliers, ST Fennessy, S. Bailey e AD Wood. "Towards the declaration of a large marine protected area: a subtidal ichthyofaunal survey of the Pondoland coast in the Eastern Cape, South Africa". African Journal of Marine Science 28, n. 3-4 (novembre 2006): 535–51. http://dx.doi.org/10.2989/18142320609504204.
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Williams, P. I., G. McFiggans e M. W. Gallagher. "Latitudinal aerosol size distribution variation in the Eastern Atlantic Ocean measured aboard the FS-Polarstern". Atmospheric Chemistry and Physics 7, n. 10 (15 maggio 2007): 2563–73. http://dx.doi.org/10.5194/acp-7-2563-2007.
Testo completoAbstract (sommario):
Abstract. Aerosol size distribution measurements from 0.03 µm to 25 µm diameter were taken at ambient humidity aboard the German research vessel, FS-Polarstern, during a transect from Bremerhaven in northern Germany, to Cape Town in South Africa across latitudes 53°32' N to 33°55' S, denoted cruise number ANT XXI/1. The data were segregated according to air mass history, wind speed and latitude. Under clean marine conditions, the averaged size distributions were generally in good agreement with those reported previously for diameters less than 0.5 µm and can be approximated by two log-normal modes, with significant variation in the mean modal diameters. Two short periods of tri-modal behaviour were observed. Above 0.5 µm, there is indication of a limit to the mechanical generation of marine aerosol over the range of wind speeds observed (~1.7–14.7 m s−1). A new technique to determine the errors associated with aerosol size distribution measurements using Poisson statistics has been applied to the dataset, providing a tool to determine the necessary sample or averaging times for correct interpretation of such data. Finally, the data were also used to investigate the loss rate of condensing gases with potentially important consequences for heterogeneous marine photochemical cycles.
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Williams, P. I., G. McFiggans e M. W. Gallagher. "Latitudinal aerosol size distribution variation in the Eastern Atlantic Ocean measured aboard the FS-Polarstern". Atmospheric Chemistry and Physics Discussions 6, n. 6 (11 dicembre 2006): 12865–93. http://dx.doi.org/10.5194/acpd-6-12865-2006.
Testo completoAbstract (sommario):
Abstract. Aerosol size distribution measurements from 0.03 μm to 25 μm diameter were taken at ambient humidity aboard the German research vessel, FS-Polarstern, during a transect from Bremerhaven in northern Germany, to Cape Town in South Africa across latitudes 53°32' N to 33°55' S, denoted cruise number ANT XXI/1. The data were segregated according to air mass history, wind speed and latitude. Under clean marine conditions, the averaged size distributions were generally in good agreement with those reported previously for diameters less than 0.5 μm and can be approximated by two log-normal modes, with significant variation in the mean modal diameters. Two short periods of tri-modal behaviour were observed. Above 0.5 μm, there is indication of a limit to the mechanical generation of marine aerosol over the range of wind speeds observed. A new technique to determine the errors associated with aerosol size distribution measurements using Poisson statistics has been applied to the dataset, providing a tool to determine the necessary sample or averaging times for correct interpretation of such data. Finally, the data were also used to investigate the loss rate of condensing gases with potentially important consequences for heterogeneous marine photochemical cycles.
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GASTALDO, ROBERT A., JOHANN NEVELING, JOHN W. GEISSMAN e CINDY V. LOOY. "TESTING THE DAPTOCEPHALUS AND LYSTROSAURUS ASSEMBLAGE ZONES IN A LITHOSTRATOGRAPHIC, MAGNETOSTRATIGRAPHIC, AND PALYNOLOGICAL FRAMEWORK IN THE FREE STATE, SOUTH AFRICA". PALAIOS 34, n. 11 (4 novembre 2019): 542–61. http://dx.doi.org/10.2110/palo.2019.019.
Testo completoAbstract (sommario):
ABSTRACT The vertebrate-fossil record in the Karoo Basin has served as the accepted model for how terrestrial ecosystems responded to the end-Permian extinction event. A database of several hundred specimens, placed into generalized stratigraphies, has formed the basis of a step-wise extinction scenario interpreted by other workers as spanning the upper Daptocephalus (=Dicynodon) to Lystrosaurus Assemblage Zones (AZ). Seventy-three percent of specimens used to construct the published model originate from three farms in the Free State: Bethel, Heldenmoed, and Donald 207 (Fairydale). The current contribution empirically tests: (1) the stratigraphic resolution of the vertebrate record on these farms; (2) whether a sharp boundary exists that delimits the vertebrate assemblage zones in these classic localities; and (3) if the Lystrosaurus AZ is of early Triassic age. We have used a multi-disciplinary approach, combining lithostratigraphy, magnetostratigraphy, vertebrate biostratigraphy, and palynology, to test these long-held assumptions. Previously reported vertebrate-collection sites have been physically placed into a litho- and magnetostratigraphic framework on the Bethel and Heldenmoed farms. The reported assemblage-zone boundary is used as the datum against which the stratigraphic position of vertebrates is compared and a preliminary magnetostratigraphy constructed. We find specimens of the Daptocephalus AZ originate in the Lystrosaurus AZ (as currently defined) and vice versa, and discrepancies between reported and field-checked stratigraphic positions below or above the assemblage-zone boundary often exceed 30 m. Hence, the utility of the data set in defining a sharp or abrupt biozone boundary is questionable. We further demonstrate the presence of a stratigraphically thick reverse polarity magnetozone that encompasses the reported assemblage-zone boundary, implying that these rocks are not correlative with the end-Permian event, which is reported to lie in a normal polarity chron. A latest Permian age is supported by palynological data from the Lystrosaurus AZ on the Donald 207 (Fairydale) farm, with equivalence to Australian (APP602) and Eastern Cape Province assemblages. We conclude that the turnover from the Daptocephalus to Lystrosaurus Assemblage Zones is more protracted than envisioned, it is not coincident with the end-Permian event as recognized in the marine realm, and little evidence exists in support of a three-phased extinction model based on vertebrate assemblages in the Karoo Basin.
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Mosavel, H., e D. I. Cole. "Lithostratigraphy of the Prince Albert Formation (Ecca Group, Karoo Supergroup)". South African Journal of Geology 122, n. 4 (1 dicembre 2019): 571–82. http://dx.doi.org/10.25131/sajg.122.0035.
Testo completoAbstract (sommario):
Abstract The Prince Albert Formation is a mudstone-dominated unit, which is located in the central and southwestern part of the Main Karoo Basin and the southernmost part of the Kalahari Basin in South Africa. It is Early Permian (Artinskian to early Kungurian) in age and is stratigraphically located between the underlying Dwyka Group and the overlying Whitehill Formation. In the Main Karoo Basin, its regional extent is limited to the cut-off boundary of the Whitehill Formation along a line from Hertzogville in the Free State to Coffee Bay in the Eastern Cape. Northeast of this boundary, it correlates with the lower part of the undifferentiated Ecca Group known as “Ecca Shales” and in the northern part of the basin, north of a line from Bloemfontein (Free State) to Harding (KwaZulu-Natal), with the Vryheid and Pietermaritzburg formations. The Prince Albert Formation is generally between 50 and 200 m thick, including the type area around Prince Albert, where a thickness of about 145 m was measured. It is thicker (230 to 497 m) in the region between Brandvlei and Jansenville and thins northeastwards to between about 30 and 60 m in the area between Kimberley and East London. In the Kalahari Basin, the formation is only 25 to 50 m thick, due to post-Karoo erosion of its upper part. The Prince Albert Formation contains fossils of marine invertebrates, palaeoniscoid fish, sharks, sponge spicules, foraminiferans, radiolarians, acritarchs, fragments of wood and leaves, together with ichnofossils in the form of fish trails, arthropod trackways and invertebrate burrows. High Rb/K ratios in the mudstones also indicate a marine shelf environment with suspension settling of mud being the predominant depositional process. Sedimentation was initiated during a major transgressive event following final melting of Dwyka Group associated ice sheets in southern Gondwana in the Late Palaeozoic. Water depths in the basin were probably about 400 m, but shallowed northeastward. In the proximal part of the basin northeast of Kimberley, sandstones in coarsening-upward successions represent prograding deltaic deposits derived from an adjacent source area to the north.
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Olds, Alexis A., Nicola C. James, M. Kyle S. Smith e Olaf L. F. Weyl. "Fish communities of the Wilderness Lakes System in the southern Cape, South Africa". Koedoe 58, n. 1 (31 marzo 2016). http://dx.doi.org/10.4102/koedoe.v58i1.1364.
Testo completoAbstract (sommario):
The Wilderness Lakes System, a temporarily open and closed estuary with three associated lakes situated in the southern Cape region of South Africa, was sampled using a range of sampling gears to assess the fish community. A total of 25 species were sampled throughout the system, with the highest diversity in the Touw Estuary (23 species) and the lowest in Langvlei (11 species). Estuary-associated marine species (13 species) dominated species richness with smaller proportions of estuarine resident (7 species), freshwater (3 species) and catadromous species (2 species). Estuarine resident species dominated the catch numerically. The size–class distribution of euryhaline marine species indicated that upon entering the Touw Estuary as juveniles, the fish move up the system towards Rondevlei where they appear to remain. Three freshwater species were recorded in the system, all of which are alien to the Wilderness Lakes System. Decreasing salinity in the upper lakes appears to be a driving factor in the distribution and increasing abundance of the freshwater fishes. Sampling followed a drought, with the system experiencing substantially increased levels of mouth closure compared to a similar study conducted in the 1980s. The timing of mouth opening and the degree of connectivity between the lakes influence the nursery function of the system as a whole. Management actions need to focus on improving ecological functioning of this system, in particular how mouth opening is managed, to facilitate nursery function and limit the establishment of invasive species.Conservation implications: Key management actions are required to improve fish recruitment potential into and within the system. These include maintenance of adequate marine inflow through adherence to artificial mouth breaching protocols and improving connectivity between the lakes through sediment removal from localised deposition points within the connecting channels.
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Lam, Wei Haur, e Stephen Oppong. "Feasibility of marine renewable energies in African coastal countries". International Journal of Renewable Energy Development, 4 gennaio 2021. http://dx.doi.org/10.14710/ijred.0.34075.
Testo completoAbstract (sommario):
Africa has 38 coastal countries with a population of 895,609,564 persons with potential to harness energy from ocean. These coastal countries are: Madagascar, South Africa, Mozambique, Angola, Namibia, Mauritius, Republic of Congo and Democratic Republic of Congo in Southern Africa with 25.31% population; Somalia, Eritrea, Tanzania, Sudan, Kenya, Seychelles, Comoros and Djibouti in Eastern Africa with 17.58% population; Egypt, Morocco, Libya, Tunisia and Algeria in Northern Africa with 20.96% population; Cape Verde, Gabon, Nigeria, Mauritania, Liberia, Ghana, Senegal, Cote d’Ivoire, Cameroon, Sierra Leone, Guinea Bissau, Guinea, Equatorial Guinea, Sao Tome and Principe, Benin, Gambia and Togo with population of 35.15%. Offshore wind, offshore solar, Tidal power, Wave energy, Salinity gradient, Ocean Thermal Energy Conversion (OTEC) are discussed with opportunities and challenges.
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Karczmarski, L., V. G. Cockcroft, A. McLachlan e P. E. D. Winter. "Recommendations for the conservation and management of humpback dolphins Sousa chinensis in the Algoa Bay region, South Africa". Koedoe 41, n. 2 (19 febbraio 1998). http://dx.doi.org/10.4102/koedoe.v41i2.257.
Testo completoAbstract (sommario):
The natural history of humpback dolphins Sousa chinensis inhabiting the Algoa Bay region. Eastern Cape, South Africa, was investigated by means of land- and sea-based surveys undertaken between May 1991 and May 1994. This article reviews the findings which are relevant to the conservation of humpback dolphins and provides recommendations for both the conservation and management of this species in Eastern Cape waters. In general, humpback dolphins appear to be typical coastal dolphins which occur in small numbers, have low population growth and depend on restricted inshore resources. Establishment of protected areas where human impact could be limited or controlled seems to be the most effective conservation/management approach. Habitats critical for humpback dolphins in Eastern Cape waters (inshore rocky reefs) and the dolphin's core areas in the Algoa Bay region have been identified. It is recommended that a conservation and management zone (marine sanctuary) in the Algoa Bay region be established and a suitable site for it is identified. Given adequate legislation and proper management, this area could be used for the development of ecotourism, including dolphin-watch operations, which would further stimulate interest in coastal conservation.
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Famewo, Elizabeth Bosede, e Anthony Jide Afolayan. "Characteristics of pathogenic bacteria isolates associated with the gut and gill of molluscan shellfish, Eastern Cape, South Africa". International Arabic Journal of Antimicrobial Agents 8, n. 2 (21 ottobre 2018). http://dx.doi.org/10.3823/822.
Testo completoAbstract (sommario):
Introduction: Infectious diseases attributable to the consumption of raw and lightly cooked molluscan shellfish are caused by bacterial agents that are associated either with human waste disposed into the ocean or those of marine origin. This has led to the increase in prevalence of bacterial diseases and microbial resistance to antibiotics.
Method: Samples of P. perna were dissected and homogenized for bacterial isolation. Six bacteria were isolated, identified and evaluated for their antimicrobial susceptibility profiling.
Results: The microbial counts obtained revealed significant differences in the pathogenic bacteria populations found in the gut and gill of Perna perna. The morphological characteristics of the isolates were found to be of different shapes. All the isolates were catalase and oxidase positive except Vibrio spp. which was negative to the latter. Chloramphenicol and ciprofloxacillin were the most effective antibiotics against all the isolates, each exhibiting 100% efficacy. The highest resistance to ampicilin was observed in Salmonella spp., Shigella spp., Listeria monocytogenes and Staphylococcus xylosus.
Conclusions: The results revealed that marine habitats are reservoirs of bacterial pathogens and there is increased resistance to antibiotic therapy, thereby constituting risks to public health. Therefore, appropriate surveillance measures to safeguard the health of shellfish consumers’ should be established.
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Cole, Mary. "The Mollusc collections at South African institutions: Development and current status". South African Journal of Science 117, n. 7/8 (29 luglio 2021). http://dx.doi.org/10.17159/sajs.2021/8984.
Testo completoAbstract (sommario):
There are three major mollusc collections in South Africa and seven smaller, thematic collections. The KwaZulu-Natal Museum holds one of the largest collections in the southern hemisphere. Its strengths are marine molluscs of southern Africa and the southwestern Indian Ocean, and terrestrial molluscs of South Africa. Research on marine molluscs has led to revisionary papers across a wide range of gastropod families. The Iziko South African Museum contains the most comprehensive collections of Cephalopoda (octopus, squid and relatives) and Polyplacophora (chitons) for southern Africa. The East London Museum is a provincial museum of the Eastern Cape. Recent research focuses on terrestrial molluscs and the collection is growing to address the gap in knowledge of this element of biodiversity. Mollusc collections in South Africa date to about 1900 and are an invaluable resource of morphological and genetic diversity, with associated spatial and temporal data. The South African National Biodiversity Institute is encouraging discovery and documentation to address gaps in knowledge, particularly of invertebrates. Museums are supported with grants for surveys, systematic studies and data mobilisation. The Department of Science and Innovation is investing in collections as irreplaceable research infrastructure through the Natural Science Collections Facility, whereby 16 institutions, including those holding mollusc collections, are assisted to achieve common targets and coordinated outputs.
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Venter, Jan A., e Bruce Q. Mann. "Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa". Koedoe 54, n. 1 (18 gennaio 2012). http://dx.doi.org/10.4102/koedoe.v54i1.1059.
Testo completoAbstract (sommario):
A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.
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Ellender, Bruce R., e Olaf L. F. Weyl. "Resilience of imperilled headwater stream fish to an unpredictable high-magnitude flood". Koedoe 57, n. 1 (25 marzo 2015). http://dx.doi.org/10.4102/koedoe.v57i1.1258.
Testo completoAbstract (sommario):
Headwater stream fish communities are increasingly becoming isolated in headwater refugia that are often cut off from other metapopulations within a river network as a result of nonnative fish invasions, pollution, water abstraction and habitat degradation downstream. This range restriction and isolation therefore makes them vulnerable to extinction. Understanding threats to isolated fish populations is consequently important for their conservation. Following a base-flow survey, a high-magnitude flood (peak flow of 1245 m-3s-1) provided an opportunity to investigate the response of endangered Eastern Cape redfin Pseudobarbus afer populations to a natural disturbance in the Waterkloof and Fernkloof streams, two relatively pristine headwater tributaries of the Swartkops River system within the Groendal Wilderness Area, Eastern Cape Province, South Africa. Pseudobarbus afer had limited distributions, occupying 3 km in both the Fernkloof and Waterkloof streams. Fish population assessments before and after the flood event indicated that there were no longitudinal trends in P. afer abundance before or after the flood, but overall abundance post-flooding in the Fernkloof stream was higher. There were no noticeable changes in P. afer size structure pre- and post-flood. Pseudobarbus afer showed resilience to a major flooding event most likely related to evolution in river systems characterised by environmental stochasticity.Conservation implications: This research provides insight into the population level responses of native headwater stream fishes to unpredictable natural disturbance. Of particular relevance is information on their ability to withstand natural disturbances, which provides novel information essential for their conservation and management especially as these fishes are already impacted by multiple anthropogenic stressors.
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Baiyegunhi, Christopher, Kuiwu Liu e Oswald Gwavava. "Grain size statistics and depositional pattern of the Ecca Group sandstones, Karoo Supergroup in the Eastern Cape Province, South Africa". Open Geosciences 9, n. 1 (13 novembre 2017). http://dx.doi.org/10.1515/geo-2017-0042.
Testo completoAbstract (sommario):
AbstractGrain size analysis is a vital sedimentological tool used to unravel the hydrodynamic conditions, mode of transportation and deposition of detrital sediments. In this study, detailed grain-size analysis was carried out on thirty-five sandstone samples from the Ecca Group in the Eastern Cape Province of South Africa. Grain-size statistical parameters, bivariate analysis, linear discriminate functions, Passega diagrams and log-probability curves were used to reveal the depositional processes, sedimentation mechanisms, hydrodynamic energy conditions and to discriminate different depositional environments. The grain-size parameters show that most of the sandstones are very fine to fine grained, moderately well sorted, mostly near-symmetrical and mesokurtic in nature. The abundance of very fine to fine grained sandstones indicate the dominance of low energy environment. The bivariate plots show that the samples are mostly grouped, except for the Prince Albert samples that show scattered trend, which is due to the either mixture of two modes in equal proportion in bimodal sediments or good sorting in unimodal sediments. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under shallow marine environments for samples from the Prince Albert, Collingham and Ripon Formations, while those samples from the Fort Brown Formation are lacustrine or deltaic deposits. The C-M plots indicated that the sediments were deposited mainly by suspension and saltation, and graded suspension. Visher diagrams show that saltation is the major process of transportation, followed by suspension.
28
Rubidge, Bruce S., Michael O. Day e Julien Benoit. "New Specimen of the Enigmatic Dicynodont Lanthanostegus mohoii (Therapsida, Anomodontia) from the Southwestern Karoo Basin of South Africa, and its Implications for Middle Permian Biostratigraphy". Frontiers in Earth Science 9 (1 giugno 2021). http://dx.doi.org/10.3389/feart.2021.668143.
Testo completoAbstract (sommario):
Lanthanostegus is an unusual dicynodont known from only two partial skulls from a single locality near Jansenville in the Eastern Cape Province of South Africa. Although these specimens can be constrained to near the base of the late middle Permian (Guadalupian) Abrahamskraal Formation, their precise age is uncertain as a result of diachroneity of the base of the Formation and the absence, in the Jansenville area, of index taxa to correlate this horizon with the biostratigraphy established in the Western Cape Province. Here, we describe a third skull that we identify as Lanthanostegus, which we recently discovered from a locality north of Laingsburg, on the western side of the main Karoo Basin. This skull reveals morphological details of the palate, occiput, and lower jaw that are not preserved in the described specimens of Lanthanostegus mohoii and will advance understanding of this poorly known dicynodont. This discovery provides the first direct correlation between the lower Abrahamskraal Formation at Jansenville on the eastern side of the basin and the southwestern part of the basin, and suggests that Lanthanostegus occurs in the lowest Tapinocephalus Assemblage Zone (AZ), or possibly to a new assemblage transitional between the Eodicynodon and Tapinocephalus AZs. This supports earlier work proposing that the Eodicynodon AZ is present only on the western side of the Karoo Basin and that the transition from a marine to continental depositional environment occurred later toward the East.
29
Jordaan, Martine S., Albert Chakona e Dewidine van der Colff. "Protected Areas and Endemic Freshwater Fishes of the Cape Fold Ecoregion: Missing the Boat for Fish Conservation?" Frontiers in Environmental Science 8 (7 dicembre 2020). http://dx.doi.org/10.3389/fenvs.2020.502042.
Testo completoAbstract (sommario):
Freshwater systems and their associated biodiversity are among the most threatened ecosystems globally. The greatest threats to freshwater fishes are the introduction and spread of non-native species, pollution, habitat degradation and loss, and overexploitation. While many regions across the world contain extensive networks of protected areas, these are largely ineffective for protecting riverine systems and their biodiversity. This is because they were designed with the aim of prioritising conservation of terrestrial biodiversity, with limited or no consideration for aquatic systems. The Cape Fold Ecoregion, located within the Western and Eastern Cape Provinces of South Africa, is home to the highest percentage of threatened freshwater fishes in the country. The region has an extensive protected area network that protects a wide array of ecosystems, but limited information exists on the role of protected areas in conserving the endemic freshwater fish fauna of this region. This study evaluated the value of protected areas for protection of freshwater fishes in the Western Cape Province by setting species conservation targets and then intersecting species distribution data with protected area polygons. Conservation targets were set to protect the minimum viable population required for long-term persistence, with a minimum of 10 subpopulations as a target. This, along with other factors such as population viability and protected area effectiveness was used to determine whether a species was effectively protected by the current protected area network. Species were classified into one of four categories; (1) “well protected,” (2) “moderately protected,” (3) “poorly protected,” and (4) “not protected.” Our results indicate that the majority of native fishes are inadequately protected within the current protected area network in the province. This is mainly a result of the linear nature of riverine ecosystems that exposes them to impacts and threats that emanate from outside of the protected area. These limitations are not unique to the CFE, and our findings have broader implications as they highlight the need for integrating both the riverine and terrestrial ecosystems in the design, expansion and management of protected areas. This will enhance and maximise conservation and protection of riverine systems and their unique biodiversity.
30
Linol, B., I. Montañez, A. Lombardo, D. Kuta, D. Upadhyay, A. Arnold, A. Tripati, A. M. Bauer e S. Musa. "Towards disentangling climatic and tectonic changes of southernmost Africa using strontium isotope stratigraphy and clumped isotope thermometry". South African Journal of Geology, 9 luglio 2021. http://dx.doi.org/10.25131/sajg.124.0045.
Testo completoAbstract (sommario):
Abstract Upper Cretaceous-Cenozoic marine sequences preserved between 30 and 350 masl across southern South Africa record a complex history of climatic and tectonic changes. In this study, we measure the strontium (Sr) isotope composition of fossil shark teeth, echinoderms, corals and oyster shells to chronostratigraphically constrain the ages of these sequences. The method requires careful petrographic screening and micro-drilling of the samples to avoid possible alteration by diagenesis. To assess palaeoenvironmental effects in the shells we measured the Mg/Ca elemental ratios and O isotope values using electron microprobe analysis (EMPA) and secondary ion mass spectrometry (SIMS). In addition, we employed carbonate clumped isotope thermometry to test palaeotemperatures reconstruction. The analysis of recent to modern stromatolites by clumped isotopes yields an average temperature of 20.2°C, in agreement with present day observations. The fossil oyster shells suggest a warmer (23.0°C) seawater palaeotemperature, possibly due to major deglaciation and sea-level rise during the Neogene. We also find that transgressions occurred above 200 to 350 m elevation during: 1) the Campanian-Maastrichian (~75 Ma); 2) the mid-Oligocene (32 to 26 Ma); and 3) the Messinian-Zanclean (6 to 5 Ma). These three episodes are linked to well-known variations in global sea level and regional tectonic processes that could have affected the continental margin differently. The most recent transgression coincides with a maximum global sea-level rise of ~50 m at ca. 5.3 Ma, and a worldwide plate kinematic change around 6 Ma, which in Eurasia led to the closure of the Mediterranean Sea. In the Eastern Cape of South Africa, the new dates of analyzed oyster shells constrain a minimum uplift rate of ca. 150 m/Myr during this tectonic activity. The results have important implications for robust calibration of relative sea level in southern Africa.
31
Humphries, M. S. "Elemental proxy evidence for late Quaternary palaeoenvironmental change in southern African sedimentary records: interpretation and applications". South African Journal of Geology, 31 luglio 2021. http://dx.doi.org/10.25131/sajg.124.0046.
Testo completoAbstract (sommario):
Abstract Sediments are the most important source of Late Quaternary palaeoclimate information in southern Africa, but have been little studied from a geochemical perspective. However, recent advances in analytical techniques that allow rapid and near-continuous elemental records to be obtained from sedimentary sequences has resulted in the increasing use of elemental indicators for reconstructing climate. This paper explores the diverse information that can be acquired from the inorganic component of sediments and reviews some of the progress that has been made over the last two decades in interpreting the climatic history of southern Africa using elemental records. Despite the general scarcity of elemental records, excellent examples from the region exist, which provide some of the longest and most highly resolved sequences of environmental change currently available. Records from Tswaing crater and marine deposits on the southern KwaZulu-Natal coastline have provided rare glimpses into hydroclimate variability over the last 200 000 years, suggesting that summer rainfall in the region responded predominantly to insolation forcing on glacial-interglacial timescales. Over shorter timescales, lakes and wetlands found in the Wilderness embayment on the southern Cape coast and along the Maputaland coast in north-eastern South Africa have yielded highly-resolved elemental records of Holocene environmental change, providing insight into the changing interactions between tropical (e.g., El Niño-Southern Oscillation) and temperate (e.g., mid-latitude westerlies) climate systems affecting rainfall variability in the region. The examples discussed demonstrate the multiple environmental processes that can be inferred from elemental proxies and the unique insight this can provide in advancing our understanding of past climate change on different timescales. The interpretation of geochemical data can be complicated by the complex nature of sedimentary environments, various proxy assumptions and analytical challenges, and the reliability of sediment-based climate reconstructions is substantially enhanced through multi-proxy approaches.