Journal articles: 'African Shelf'

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STEPHAN, TOBIAS, UWE KRONER, and ROLF L. ROMER. "The pre-orogenic detrital zircon record of the Peri-Gondwanan crust." Geological Magazine 156, no. 2 (February 8, 2018): 281–307. http://dx.doi.org/10.1017/s0016756818000031.

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AbstractWe present a statistical approach to data mining and quantitatively evaluating detrital age spectra for sedimentary provenance analyses and palaeogeographic reconstructions. Multidimensional scaling coupled with density-based clustering allows the objective identification of provenance end-member populations and sedimentary mixing processes for a composite crust. We compiled 58 601 detrital zircon U–Pb ages from 770 Precambrian to Lower Palaeozoic shelf sedimentary rocks from 160 publications and applied statistical provenance analysis for the Peri-Gondwanan crust north of Africa and the adjacent areas. We have filtered the dataset to reduce the age spectra to the provenance signal, and compared the signal with age patterns of potential source regions. In terms of provenance, our results reveal three distinct areas, namely the Avalonian, West African and East African–Arabian zircon provinces. Except for the Rheic Ocean separating the Avalonian Zircon Province from Gondwana, the statistical analysis provides no evidence for the existence of additional oceanic lithosphere. This implies a vast and contiguous Peri-Gondwanan shelf south of the Rheic Ocean that is supplied by two contrasting super-fan systems, reflected in the zircon provinces of West Africa and East Africa–Arabia.

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Penter, M. G., I. Bertling, and A. D. Sippel. "Factors affecting shelf life of South African macadamias." Acta Horticulturae, no. 1109 (February 2016): 11–16. http://dx.doi.org/10.17660/actahortic.2016.1109.2.

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Micallef, Aaron, Aggeliki Georgiopoulou, Andrew Green, and Vittorio Maselli. "Impact of sea-level fluctuations on the sedimentation patterns of the SE African margin: implications for slope instability." Geological Society, London, Special Publications 500, no. 1 (December 19, 2019): 267–76. http://dx.doi.org/10.1144/sp500-2019-172.

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AbstractThe sheared-passive margin offshore Durban (South Africa) is characterized by a narrow continental shelf and steep slope hosting numerous submarine canyons. Supply of sediment to the margin is predominantly terrigenous, dominated by discharge from several short but fast-flowing rivers. International Ocean Discovery Program Expedition 361 provides a unique opportunity to investigate the role of sea-level fluctuations on the sedimentation patterns and slope instability along the South African margin. We analysed >300 sediment samples and downcore variations in P-wave, magnetic susceptibility, bioturbation intensity and bulk density from site U1474, as well as regional seismic reflection profiles to: (1) document an increase in sand input since the Mid-Pliocene; (2) associate this change to a drop in sea-level and extension of subaerial drainage systems towards the shelf-edge; (3) demonstrate that slope instability has played a key role in the evolution of the South Africa margin facing the Natal Valley. Furthermore, we highlight how the widespread occurrence of failure events reflects the tectonic control on the morphology of the shelf and slope, as well as bottom-current scour and instability of fan complexes. This information is important to improve hazard assessment in a populated coastal region with growing offshore hydrocarbon activities.

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Habashi, Bareh Bahgat, Andrzej Kompowski, and Jan Wojciechowski. "Food and feeding of chub mackerel, Scomber japonicus Houttuyn, 1782 in the north-west African shelf." Acta Ichthyologica et Piscatoria 17, no. 1 (June 30, 1987): 77–92. http://dx.doi.org/10.3750/aip1987.17.1.06.

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D'Avignon, Robyn. "Shelf Projects: The Political Life of Exploration Geology in Senegal." Engaging Science, Technology, and Society 4 (March 1, 2018): 111. http://dx.doi.org/10.17351/ests2018.210.

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Since the early 2000s, southeastern Senegal has emerged as a premier gold exploration and mining frontier. At present, the Sabodala gold mine, owned by the Canadian company Teranga Gold, is the only operational gold mine and mill in Senegal. But two more open-pit gold operations are scheduled to open this year, and several other companies have announced discoveries of industrial-scale deposits. By documenting the shifting ownership and exploration of the Sabodala deposit, this article draws attention to how the protracted phase of mineral research shapes the political life of mining operations in Africa and elsewhere in the global South. Geological exploration in colonial and post-colonial Senegal, as in much of Africa, has relied heavily on the expertise of indigenous miners and smelters. Mining Sabodala has thus unearthed multi-vocal and contested histories of gold discovery. Historians of science have established that field assistants and experts in Africa have produced agronomic and medical knowledge typically credited to “the West.” By extending this argument to gold exploration, the article brings African history into dialogue with an emergent anthropology of subterranean knowledge production.

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Kijewska, Agnieszka, Joanna Dzido, Olga Shukhgalter, and Jerzy Rokicki. "Anisakid Parasites of Fishes Caught on the African Shelf." Journal of Parasitology 95, no. 3 (June 2009): 639–45. http://dx.doi.org/10.1645/ge-1796.1.

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Lavik, Gaute, Torben Stührmann, Volker Brüchert, Anja Van der Plas, Volker Mohrholz, Phyllis Lam, Marc Mußmann, et al. "Detoxification of sulphidic African shelf waters by blooming chemolithotrophs." Nature 457, no. 7229 (December 10, 2008): 581–84. http://dx.doi.org/10.1038/nature07588.

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Mhammdi, Nadia, Maria Snoussi, Fida Medina, and El Bachir Jaaïdi. "Chapter 10 Recent sedimentation in the NW African shelf." Geological Society, London, Memoirs 41, no. 1 (2014): 131–46. http://dx.doi.org/10.1144/m41.10.

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Arkhipkin, Alexander, and Nataly Nekludova. "Age, growth and maturation of the loliginid squids Alloteuthis africana and A. Subulata on the west African shelf." Journal of the Marine Biological Association of the United Kingdom 73, no. 4 (November 1993): 949–61. http://dx.doi.org/10.1017/s0025315400034822.

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Samples of two loliginid squids Alloteuthis africana and A. subulata were collected from the continental shelf off the west Sahara in August-September 1987. Statoliths were taken from 124 specimens and processed using statolith ageing techniques. Statoliths of both species were very similar in shape. In the ground statolith, growth increments were examined and grouped into four growth zones distinguished mainly by the width of the increments. Age of adult mature males of both species did not exceed eight months, that of females six months. Alloteuthis africana grew faster than A. subulata in weight and, particularly, in length. At age 180 d the mantle of A. africana was twice as long and the body weight 1·2–1·5 times as large. Both species matured over a wide range of sizes and ages (from 120 to 180 d). The life span of A. africana and A. subulata hatching between January and May on the west Saharan shelf is about six months, much shorter than that of A. subulata in its northern temperate range.

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Roberts, Michael J., Nicola J. Downey, and Warwick H. Sauer. "The relative importance of shallow and deep shelf spawning habitats for the South African chokka squid (Loligo reynaudii)." ICES Journal of Marine Science 69, no. 4 (February 23, 2012): 563–71. http://dx.doi.org/10.1093/icesjms/fss023.

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Abstract Roberts, M. J., Downey, N. J., and Sauer, W. H. 2012. The relative importance of shallow and deep shelf spawning habitats for the South African chokka squid (Loligo reynaudii). – ICES Journal of Marine Science, 69: 563–571. It is well known that the spawning grounds of chokka squid Loligo reynaudii lie along the shallow inshore regions of South Africa's south coast. However, egg masses have been found in deeper water on the Agulhas Bank, and hydroacoustic targets deemed to be large aggregations of spawning squid have been identified. The aim of this study was to investigate the extent, depth range, and importance of deep spawning. Trawl data collected during demersal research surveys between Port Nolloth on the west and Port Alfred on the south coast were examined for egg capsules. No spawning was found on the west coast. Data showed that chokka squid preferred the eastern Agulhas Bank for spawning. Spawning occurred not only inshore but also on the mid-shelf extending to depths of 270 m near the shelf edge. Squid egg biomass markedly decreased beyond 70 m, suggesting delineation between the inshore and offshore spawning grounds. Total egg biomass calculations for depths shallower and deeper than 70 m indicated the coastal area to be strongly favoured, i.e. 82 vs. 18%. These results contest the commonly accepted notion that L. reynaudii is an inshore spawner and redefine the spawning grounds to extend across the shelf.

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Lézine, Anne-Marie. "Evolution of the West African Mangrove During the Late Quaternary: A Review." Palynologie et changements globaux : XIVe symposium de l’Association des palynologues de langue française 51, no. 3 (November 30, 2007): 405–14. http://dx.doi.org/10.7202/033139ar.

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ABSTRACT The review of pollen data on mangrove pollen deposition in modern and late Quaternary sediments of West Africa points to two distinct signals linked to the sedimentary environment concerned. Along the littoral and on the slope of the continental shelf, mangrove peat deposits recording more than 40% of Rhizophora percentages reflect the postglacial sea-level rise and give evidence for the associated paleogeographical modifications (e.g. during the Nouakchottian transgression). Deep oceanic records show that the mangrove was present along the West African coasts during the Late Glacial Maximum reflecting local conditions of fresh water input and sea surface temperatures not as low as previously suggested. Mangrove developed after 12 500 BP as far north as 21°N; its maximum extension was recorded ca. 9500 BP reflecting the enhanced monsoon circulation over West Africa.

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Fawole, Olaniyi Amos, Shannon Claudia Riva, and Umezuruike Linus Opara. "Efficacy of Edible Coatings in Alleviating Shrivel and Maintaining Quality of Japanese Plum (Prunus salicina Lindl.) during Export and Shelf Life Conditions." Agronomy 10, no. 7 (July 16, 2020): 1023. http://dx.doi.org/10.3390/agronomy10071023.

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The effect of six edible coatings were investigated on the ability to alleviate shrivel and extend shelf life of plums. Fruit were subjected to a simulated shipping period (−0.5 ± 2 °C and 90 ± 5% relative humidity (RH)) for five weeks and a subsequent shelf life period (20 ± 2 °C and 80 ± 5% RH) for 20 d. Overall, the study showed that it is possible to alleviate shrivel and also extend shelf life of plum (‘African Delight™’) at export and shelf life conditions. Amongst the edible coatings investigated, the findings in fruit coated with gum arabic and the commercial products were comparable and promising for postharvest preservation of the investigated plum cultivar. The coatings showed a moderate delay of fruit ripening, significantly reduced weight loss and shrivel development, allowing for the export of fruit over a long distance (five weeks) and up to 20 d of shelf life.

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Aworh, Ogugua C., and Moutairou Egounlety. "Preservation of West African soft cheese by chemical treatment." Journal of Dairy Research 52, no. 1 (February 1985): 189–95. http://dx.doi.org/10.1017/s0022029900024018.

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SUMMARYThe effects of sorbic and propionic acids on shelf life and organoleptic characteristics of West African soft cheese stored at 7–9 °C were investigated. In cheeses treated with 0·1% sorbic acid spoilage was delayed and microbial growth, especially mesophilic bacteria, yeasts and moulds, was suppressed compared with untreated controls. Treatment with 0·05% sorbic acid or up to 10% propionic acid was less effective. An objectionable bitter flavour was reported for sorbate-treated cheese but other qualities were not adversely affected.

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Ryan, Peter G., Eleanor A. Weideman, Vonica Perold, Deon Durholtz, and Tracey P. Fairweather. "A trawl survey of seafloor macrolitter on the South African continental shelf." Marine Pollution Bulletin 150 (January 2020): 110741. http://dx.doi.org/10.1016/j.marpolbul.2019.110741.

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Kelly, J., and H. Doust. "Exploration for Late Cretaceous turbidites in the Equatorial African and northeast South American margins." Netherlands Journal of Geosciences - Geologie en Mijnbouw 95, no. 4 (October 18, 2016): 393–403. http://dx.doi.org/10.1017/njg.2016.36.

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AbstractThe Suriname–Guyana and Ghana–Ivorian Basins exhibit strong geological similarities which are of interest from a petroleum exploration point of view. These include (1) a well-developed system of Late Cretaceous erosional canyons allowing coarse-grained shallow-water clastics to enter the deep marine basin to form attractive turbidite exploration targets; (2) a broad shelf with strong longshore currents which sort and transport coarse clastics into the canyon heads; (3) an organic-rich Cenomanian–Turonian hydrocarbon source rock which is thermally mature in the centre of the basin; and (4) a series of extensional fault-networks along the shelf margin that extend upwards from the Rift Sequence into the overlying Drift Sequence and which, along with the canyon geometries, enable migrating oil and gas to accumulate in combination structural and stratigraphic traps. In June 2007, Tullow and its partners made an important discovery in offshore Ghana, at Mahogany, which subsequently became the giant Jubilee field. Tullow is currently applying the same geoscientific technologies in offshore Suriname in the search for analogous subtle combination traps.

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Park, Suejin, Sarah A. Mills, Youyoun Moon, and Nicole L. Waterland. "Evaluation of Antitranspirants for Enhancing Temporary Water Stress Tolerance in Bedding Plants." HortTechnology 26, no. 4 (August 2016): 444–52. http://dx.doi.org/10.21273/horttech.26.4.444.

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Water stress during shipping and retailing reduces the postproduction quality and marketability of bedding plants. Antitranspirants can temporarily prevent plants from wilting by either physically blocking stomata or physiologically inducing stomatal closure, limiting transpirational water loss from leaves. The goal of this research was to evaluate the efficacy of commercially available antitranspirants on enhancing temporary water stress tolerance in bedding plants. Two physical antitranspirants [β-pinene polymer (βP) and vinyl-acrylic polymer (VP)], and three physiological antitranspirants [two sugar alcohol-based compounds (SACs) and a biologically active form of abscisic acid (s-ABA)] were applied to begonia (Begonia semperflorens-cultorum), new guinea impatiens (Impatiens hawkeri), impatiens (Impatiens walleriana), petunia (Petunia ×hybrida), african marigold (Tagetes erecta), and french marigold (Tagetes patula). Physical antitranspirants were sprayed on foliage and physiological antitranspirants were drenched to the media. All antitranspirants were applied at half (0.5×), equal to (1×), or twice (2×) the manufacturer’s recommended rate. Extended shelf life was observed when βP or s-ABA was applied. Treatment with βP increased the shelf life of impatiens and african marigold by 1 and 1.3 days compared with control plants, respectively. The application of βP at 2× was more effective at delaying visual wilting than at lower rates (0.5× and 1×) in african marigold. Applications of s-ABA delayed wilting by 1.3 to 3.7 days in all tested cultivars. The shelf lives of impatiens and petunia treated with s-ABA at 2× were extended the most by 3.7 and 3.0 days compared with control plants, respectively. A rapid reduction of stomatal conductance (gS) was observed within 4 hours of βP or s-ABA application in plants showing delayed wilting symptoms. s-ABA treatment appeared to cause marginal leaf chlorosis in impatiens, whereas application of βP damaged the opened flowers in all tested cultivars. The application of VP or SACs did not extend shelf life in any treated plants. These results suggest that foliar application of βP on selected species and treatment with s-ABA on most of species would allow bedding plants to withstand water deficit during shipping and/or retailing.

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Steinke, Dirk, Allan D. Connell, and Paul D. N. Hebert. "Linking adults and immatures of South African marine fishes." Genome 59, no. 11 (November 2016): 959–67. http://dx.doi.org/10.1139/gen-2015-0212.

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The early life-history stages of fishes are poorly known, impeding acquisition of the identifications needed to monitor larval recruitment and year-class strength. A comprehensive database of COI sequences, linked to authoritatively identified voucher specimens, promises to change this situation, representing a significant advance for fisheries science. Barcode records were obtained from 2526 early larvae and pelagic eggs of fishes collected on the inshore shelf within 5 km of the KwaZulu-Natal coast, about 50 km south of Durban, South Africa. Barcodes were also obtained from 3215 adults, representing 946 South African fish species. Using the COI reference library on BOLD based on adults, 89% of the immature fishes could be identified to a species level; they represented 450 species. Most of the uncertain sequences could be assigned to a genus, family, or order; only 92 specimens (4%) were unassigned. Accumulation curves based on inference of phylogenetic diversity indicate near-completeness of the collecting effort. The entire set of adult and larval fishes included 1006 species, representing 43% of all fish species known from South African waters. However, this total included 189 species not previously recorded from this region. The fact that almost 90% of the immatures gained a species identification demonstrates the power and completeness of the DNA barcode reference library for fishes generated during the 10 years of FishBOL.

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Junker, Tim, Volker Mohrholz, Martin Schmidt, Lydia Siegfried, and Anja van der Plas. "Coastal Trapped Wave Propagation along the Southwest African Shelf as Revealed by Moored Observations." Journal of Physical Oceanography 49, no. 3 (March 2019): 851–66. http://dx.doi.org/10.1175/jpo-d-18-0046.1.

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AbstractCoastal trapped waves (CTWs) that propagate poleward along the southwest African shelf potentially leak energy from lower latitudes into the Benguela Upwelling System (BUS). Thus, in addition to local winds, these waves provide an important remote forcing mechanism for the upwelling region. The present study aims at elucidating the nature of CTWs in the northern BUS. To this end, we make use of multisite velocity observations from the Namibian shelf (18°, 20°, 23°S) and examine the alongshore velocity signal for signatures of CTWs by means of wavelet methods. We found that a substantial amount of energy is concentrated within a submonthly to subseasonal frequency band (10–50 days). Based on the coherence and phase spectra of the alongshelf currents, we provide evidence for a predominantly southward phase propagation and establish typical time and length scales of CTWs in the region. It turns out that their properties differ significantly within a few hundred kilometers along the coast. A comparison of the results with theoretical dispersion curves shows that this difference may be explained by variations in the bottom topography. Finally, we investigate the coupling of the alongshore currents with the coastal and equatorial wind stress and highlight regions of potential wave generation.

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Arkhipkin, Alexander I., and Vladimir V. Laptikhovsky. "Age and growth of the squid Todaropsis eblanae (Cephalopoda: Ommastrephidae) on the north-west African shelf." Journal of the Marine Biological Association of the United Kingdom 80, no. 4 (August 2000): 747–48. http://dx.doi.org/10.1017/s0025315400002642.

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Length composition, maturation and growth of the ommastrephid squid Todaropsis eblanae were studied using length–frequency distributions (LFDs) and statoliths of squid caught off the north-west African coast. Length–frequency distributions were quite similar in all seasons studied, indicating all year round spawning. However, both high proportions of mature squid in the winter and the hatching peak of squid from our sample in spring suggested the winter–spring peak of spawning. Immature and maturing squid had rather high growth rates, attaining 140—150 mm of dorsal mantle length (ML) by the age of 160—170 d. Todaropsis eblanae is likely to have an annual life cycle on the north-west African shelf.

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Adams, Luther A., Gavin W. Maneveldt, Andrew Green, Natasha Karenyi, Denham Parker, Toufiek Samaai, and Sven Kerwath. "Rhodolith Bed Discovered off the South African Coast." Diversity 12, no. 4 (March 27, 2020): 125. http://dx.doi.org/10.3390/d12040125.

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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.

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Green, Andrew N., J. Andrew G. Cooper, and Leslee Salzmann. "The role of shelf morphology and antecedent setting in the preservation of palaeo-shoreline (beachrock and aeolianite) sequences: the SE African shelf." Geo-Marine Letters 38, no. 1 (June 17, 2017): 5–18. http://dx.doi.org/10.1007/s00367-017-0512-8.

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Botha, JA, SP Kirkman, JPY Arnould, AT Lombard, GJG Hofmeyr, MA Meÿer, PGH Kotze, and PA Pistorius. "Geographic variation in at-sea movements, habitat use and diving behaviour of female Cape fur seals." Marine Ecology Progress Series 649 (September 10, 2020): 201–18. http://dx.doi.org/10.3354/meps13446.

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Knowledge of animal foraging behaviour has implications for management and conservation. While Cape fur seals Arctocephalus pusillus pusillus comprise a major proportion of the southern African marine predator biomass, little is known about their at-sea movements. We investigated foraging distribution, habitat use and diving behaviour for 35 adult female Cape fur seals from 3 breeding colonies experiencing contrasting oceanographic regimes. Animals from Black Rocks, the smallest and eastern-most colony, undertook shorter foraging trips and utilised shallower waters over the shelf. In comparison, animals from the larger west coast colonies, at Kleinsee and False Bay, travelled further and utilised deeper shelf and shelf-slope waters. However, across colonies, females typically preferred depths of <500 m and slopes of <5°. Kleinsee and False Bay seals selected sea surface temperatures within the range typically preferred by pelagic prey species such as round herring, sardine and anchovy (14-19°C). Black Rocks individuals showed bimodal preferences for colder (16°C) and warmer waters (>22°C). Dive behaviour was similar between Kleinsee and False Bay individuals (unavailable from Black Rocks), with both pelagic and benthic foraging evident. Diel patterns were apparent at both sites, as dive depth and benthic diving increased significantly during daylight hours, likely reflecting vertical movements of prey species. We provide the first assessment of Cape fur seal movement behaviour for the South African component of the population. Observed geographic differences likely reflect the availability of suitable habitat but may also indicate differences in foraging strategies and density-dependent effects throughout the range of this species.

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Liu, Xiting, Rebecca Rendle-Bühring, and Rüdiger Henrich. "Geochemical composition of Tanzanian shelf sediments indicates Holocene climatic and sea-level changes." Quaternary Research 87, no. 3 (April 5, 2017): 442–54. http://dx.doi.org/10.1017/qua.2017.12.

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AbstractWe present a high-resolution geochemical and grain-size record from a Holocene sediment core off the Pangani River mouth, Tanzania. Elemental ratios between biogenic elements and Al (i.e., Ca/Al, Mg/Al, and Sr/Al) are mainly influenced by terrigenous dilution on carbonate concentration and/or limitation of carbonate production as a result of variations in the supply of fine-grained terrigenous sediments of the Pangani River. Such elemental ratios increased significantly at the end of the mid-Holocene between 5 and 3.5 ka, demonstrating a gradual transition from the humid early and mid-Holocene to the arid late Holocene in East Africa. Among the elemental ratios between terrigenous elements and Al, Si/Al and K/Al ratios correlate to grain-size variation, indicating a change in sedimentation regime. Fe/Al and Ti/Al ratios show that the sediment source area has shifted from the terrestrial volcanic region of Tanzania (Fe, Ti rich) to the coastal and inner-shelf regions (Fe, Ti poor) around 7.5 ka, in response to arid climate and high sea level. Our geochemical results correspond with a sea-surface temperature record derived from the same sediment core, indicating that the end of the East African Humid Period could have been gradual and related to the cooling water in the western Indian Ocean.

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Henry, Annette E. "The Empty Shelf and Other Curricular Challenges of Teaching for Children of African Descent." Urban Education 29, no. 3 (October 1994): 298–319. http://dx.doi.org/10.1177/0042085994029003004.

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Argyriadis, I., M. Midoun, and P. Ntontos. "A NEW INTERPRETATION OF THE STRUCTURE OF INTERNAL HELLENIDES." Bulletin of the Geological Society of Greece 43, no. 1 (January 19, 2017): 264. http://dx.doi.org/10.12681/bgsg.11179.

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This study is based on some new observations made from Southern and Central Evia, Argolis and North-central part of Pindos. Our observations lead us to adopt a simplified view of the paleogeography of Greek mainland just before the Alpine orogeny. The subsequent varied tectonic units originate mainly from the following paleogeographic areas:• A carbonate Arab-African shelf margin which displays several lateral transitions, ridges and basins. In the Greek mainland this margin is represented by the Preapulian, Ionian, GavrovoTripolis, Parnassos zones, Olympus platform and probably the Kavala and Thassos Marbles.• A transition zone from the shelf units to the Tethys ophiolites (Pindos Zone, Styra, Argolis and Hydra, Eretrias new unit).• Tethys ophiolites, which might represent an “ocean” fault zone or subduction of lithosphere along a weak zone.• An Hercynian continental mass (Servomacedonian).

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Neto, Carlos, José Carlos Costa, Albano Figueiredo, Jorge Capelo, Isildo Gomes, Sónia Vitória, José Maria Semedo, et al. "The Role of Climate and Topography in Shaping the Diversity of Plant Communities in Cabo Verde Islands." Diversity 12, no. 2 (February 19, 2020): 80. http://dx.doi.org/10.3390/d12020080.

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The flora and vegetation of the archipelago of Cabo Verde is dominated by Macaronesian, Mediterranean, and particularly by African tropical elements, resulting from its southernmost location, when compared to the other islands of the Macaronesia (i.e., Azores, Madeira, Selvagens, and Canary Islands). Very likely, such a geographical position entailed higher susceptibility to extreme climatic fluctuations, namely those associated with the West African Monsoon oscillations. These fluctuations led to a continuous aridification, which is a clear trend shown by most recent studies based on continental shelf cores. Promoting important environmental shifts, such climatic fluctuations are accepted as determinant to explain the current spatial distribution patterns of taxa, as well as the composition of the plant communities. In this paper, we present a comprehensive characterization of the main plant communities in Cabo Verde, and we discuss the role of the climatic and topoclimatic diversity in shaping the vegetation composition and distribution of this archipelago. Our study reveals a strong variation in the diversity of plant communities across elevation gradients and distinct patterns of richness among plant communities. Moreover, we present an overview of the biogeographical relationships of the Cabo Verde flora and vegetation with the other Macaronesian Islands and northwestern Africa. We discuss how the distribution of plant communities and genetic patterns found among most of the endemic lineages can be related to Africa’s ongoing aridification, exploring the impacts of a process that marks northern Africa from the Late Miocene until the present.

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Hayward, Craig J. "Distribution of external parasites indicates boundaries to dispersal of sillaginid fishes in the Indo-West Pacific." Marine and Freshwater Research 48, no. 5 (1997): 391. http://dx.doi.org/10.1071/mf96125.

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The distribution of sillaginid-specific ectoparasites permits the distinction of two provinces with high parasite diversity: one on the continental shelf of Australia, and one on the shelf of Asia. The Australian province has 15 endemics (five monogeneans, one leech and nine copepods), and the Asian province has 14 endemics (two monogeneans and 12 copepods). These provinces are separated by a region with coastlines that descend very steeply to the ocean floor and by deep ocean waters that largely inhibit sillaginid movements. Some sillaginids must have dispersed across eastern Indonesia, however, leading to the occurrence of four parasites in both provinces. Three Australian parasites also appear to be presently encroaching onto the southern periphery of the Asian shelf. At least one less-recent invasion of Australian waters by Asian sillaginids would account for the occurrence of six pairs of copepod congeners that have one member in each province. The most widespread sillaginid, Sillago sihama, seems to have dispersed to African shores from the Arabian Sea as planktonic larvae only (no Asian parasites were present in samples of 29 hosts) and relatively recently (only one locally endemic parasite appears to have been acquired).

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Kawo, Hassen Muhammad. "Islamic Manuscript Collections in Ethiopia." Islamic Africa 6, no. 1-2 (July 6, 2015): 192–200. http://dx.doi.org/10.1163/21540993-00602012.

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Ethiopian Muslims introduced literary culture and manuscript collection in the mosques after the introduction of Islam in the seventh century. Books stored and preserved in a bookshelves known as taqet (Arabic, tāqat, shelf). This clearly shows African endogenous culture of preserving textual material that before the introduction of European models for archives and museums. This article demonstrates the collection of Islamic manuscripts in Ethiopian state archives and private collections and illustrates their challenges with recommendation to rescue the collections.

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de Bruyn, P. J. N., G. J. G. Hofmeyr, and M. S. de Villiers. "First record of a vagrant Commerson's dolphin, Cephalorhynchus commersonii, at the southern African continental shelf." African Zoology 41, no. 1 (April 2006): 131–33. http://dx.doi.org/10.3377/1562-7020(2006)41[131:froavc]2.0.co;2.

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de Bruyn, P. J. N., G. J. G. Hofmeyr, and M. S. de Villiers. "First record of a vagrant Commerson’s dolphin, Cephalorhynchus commersonii, at the southern African continental shelf." African Zoology 41, no. 1 (April 2006): 131–33. http://dx.doi.org/10.1080/15627020.2006.11407343.

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Ochieng, Judith Muhonja, and Janice D. Crist. "“I put diabetes on the shelf”: African-American Women’s Perceptions of Risk for Diabetes Complications." Clinical Nursing Research 30, no. 7 (February 22, 2021): 1012–22. http://dx.doi.org/10.1177/1054773821996551.

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The purpose of this study was to describe the perceptions of African American (AA) women with Type 2 diabetes mellitus (T2DM) about developing diabetes mellitus (DM) complications and explore how their perceived risk influenced DM self-management. Ten ( N = 10) AA women participated in the qualitative description study through semi-structured interviews. Thematic analysis informed by the Health Belief Model and Risk Perception Conceptual Model revealed the perceived probability of DM complications by AA women with T2DM and how they made judgments regarding the seriousness, extent, or severity of complications. Those with high levels of DM knowledge perceived themselves at high risk of developing DM complications and those with low DM knowledge perceived themselves at low risk of DM complications. Risk perceptions and health literacy also influenced DM self-management behaviors.

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Lamont, T., M. A. van den Berg, and R. G. Barlow. "Agulhas Current Influence on the Shelf Dynamics of the KwaZulu-Natal Bight." Journal of Physical Oceanography 46, no. 4 (April 2016): 1323–38. http://dx.doi.org/10.1175/jpo-d-15-0152.1.

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AbstractThe Agulhas Current is a fast western boundary current flowing along the South African east coast, strongly influencing oceanographic variability on the adjacent KwaZulu-Natal shelf. Hydrographic observations in January 2010, July 2010, and July 1989 have been used to describe variations in geostrophic currents and water masses and to elucidate mechanisms of change in circulation and thermohaline structure. Differences in wind forcing, precipitation, and solar insolation caused modifications in stratification and mixing that resulted in seasonal changes in surface temperature, salinity, and mixed layer depth ZMLD between the austral summer and winter surveys. During January 2010, surface temperatures were elevated and there was a large range in salinity as the upper 10 m was influenced by river outflow and rainfall. In July 2010 and 1989, surface temperatures were lower and the salinity range was significantly less. The ZMLD in January 2010 was much shallower, varying between 5 and 40 m, while deeper ZMLD, from 9 to 107 m, was found in July 2010 and 1989. Cross-shelf, alongshore, and vertical variations in water masses during July 2010 and July 1989 were driven by deviations in the position of the inshore edge of the Agulhas Current and the influence of offshore cyclonic eddies. In January 2010, the close proximity of the current to the coast and shelf break caused increased Ekman veering in the bottom layers along the shelf edge and slope in the north and recirculation in the south.

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Djameh, C., W. O. Ellis, I. Oduro, F. K. Saalia, Y. M. Blay, and G. A. Komlaga. "West African sorghum beer fermented with Lactobacillus delbrueckii and Saccharomyces cerevisiae: shelf-life and consumer acceptance." Journal of the Institute of Brewing 125, no. 3 (2019): 333–41. http://dx.doi.org/10.1002/jib.563.

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Catewicz, Zygmunt. "On the variability of currents in the coastal zone of the African Shelf at 16° North." Deutsche Hydrographische Zeitschrift 38, no. 2 (March 1985): 69–92. http://dx.doi.org/10.1007/bf02226670.

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Gentil, Mathieu, France Floc'h, Thomas Meunier, Angel Ruiz-Angulo, Gildas Roudaut, Yannick Perrot, and Anne Lebourges-Dhaussy. "Internal solitary waves on the NW African shelf: A heuristic approach to localize diapycnal mixing hotspots." Continental Shelf Research 226 (September 2021): 104492. http://dx.doi.org/10.1016/j.csr.2021.104492.

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OWADE, JOSHUA OMBAKA, GEORGE OOKO ABONG, and MICHAEL WANDAYI OKOTH. "Production, Utilization and Nutritional benefits of Orange Fleshed Sweetpotato (OFSP) Puree Bread: A Review." Current Research in Nutrition and Food Science Journal 6, no. 3 (December 14, 2018): 644–55. http://dx.doi.org/10.12944/crnfsj.6.3.06.

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Bread though an exotic food product in sub-Saharan Africa, has been an important cereal product consumed by most individuals among the vast Sub-Saharan African population. Bread formulations in both the local and industrial production have evolved. The latest and emerging technology in bread formulation involve the incorporation of orange-fleshed sweetpotato (OFSP) puree. OFSP puree-based bread is commercially available across sub-Saharan Africa (SSA) and is being promoted due to the potential nutritional benefits that it possesses. Together with OFSP flour based bread, OFSP puree based bread serves as a good food vehicle for β-carotene; this serves to alleviate vitamin A deficiency (VAD) especially among the vulnerable population in SSA. The production of OFSP puree based bread has so far been relying on fresh OFSP puree or cold-chain stored OFSP puree. However, this has presented economic challenges and problems to the sustainability and expansion in OFSP puree bread production. Cold chain stored OFSP puree is capital intensive and has inconsistent supply. With the development of shelf-storable preservative treated OFSP puree, most of these challenges will be overcome without undoing the currently harnessed benefits. The use of OFSP puree in bread baking can then be expanded easily at minimal production costs and maximum retention of nutritional quality. Therefore, the use of the shelf-storable OFSP puree in bread baking needs to be evaluated further to present a substantiated case for its use. The current review has been developed with focus on the scientific advances in the production of OFSP puree based bread from both historical and a forecast perspective. The scientific progress and breakthroughs in the use of OFSP puree in bread are critically reviewed.

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Jury, Mark R. "Environmental Influences on South African Fish Catch: South Coast Transition." International Journal of Oceanography 2011 (January 23, 2011): 1–10. http://dx.doi.org/10.1155/2011/920414.

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This study considers environmental factors influencing aggregate fish catch in the South Coast transition of South Africa. The environmental forcing is studied via (i) seasonal analysis of SeaWifs chlorophyll and related variables, (ii) composite analysis of atmospheric and oceanographic reanalysis data, (iii) statistical analysis of annual FAO fish catch with climatic indices, and (iv) analysis of depth-latitude hydrographic sections over the shelf (33–36S, 22–26E). In years of higher fish catch there is a northward shift of the subtropical anticyclones and upwelling that is partially related to Pacific El Nino. Westerly troughs skirt the Agulhas Bank creating onshore Ekman transport. Higher sea surface height inshore, and cooler sea temperatures and lower salinity offshore induce a gradient that weakens the Agulhas Current. These environmental conditions favour the southeastward migration of juvenile fish from west to south coast. A multivariate model of aggregate fish stocks, using four environmental variables: salinity and zonal currents in the Agulhas Current, sea temperature in the Agulhas source region, and geopotential height over the Cape, accounts for 53% of variance at 0-1 year lead. Freshening of the boundary current is a factor influencing aggregate fish catch in the South Coast transition.

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Amponsah, Samuel K. K., Berchie Asiedu, Selasi Yao Avornyo, Seyramsarah Blossom Setufe, and Pierre Failler. "Growth, Mortality and Exploitation Rates of African Moonfish (Selene dorsalis, Gill 1863) Encountered in the Coast of Ghana (West Africa)." European Journal of Biology and Biotechnology 2, no. 2 (March 9, 2021): 6–10. http://dx.doi.org/10.24018/ejbio.2021.2.2.154.

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Growth, mortality and exploitation rate of Selene dorsalis (Gill, 1863) from the continental shelf of Ghana (West Africa) were examined between July 2018 and June 2019. The study provided results on fishery dynamics parameters needed to estimate the stock status and characteristics of S. dorsalis in the coast of Ghana. Monthly length-frequency data were collected from 629 samples and analysed using fisheries models fitted in TropFishR package in R software. The von Bertalanffy growth parameters were utilised to analyse the population dynamics of the species using ELEFAN Simulating Annealing. Based on the estimates, the asymptotic total length (L∞) was 22.2 cm, the coefficient of growth (K) was 0.76 year-1, and the calculated growth performance index (phi) was 2.58 with Rn value of 0.55. The total mortality rate (Z) was 3.32 year-1 with a natural mortality rate (M) of 1.21 year-1 and fishing mortality rate (F) of 2.11 year-1. The exploitation rate (E) estimated for the species was above the optimum level of 0.5, which indicates that S. dorsalis is overexploited in the coast of Ghana. It can be concluded that the exploitation rate of S. dorsalis has exceeded the optimum limit, hence the need for enforcement and improvement of fisheries management measures such as mesh size regulations, capping of canoes, closed fishing seasons and compliance with fisheries policies.

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Purdon, Jean, Fannie W. Shabangu, Dawit Yemane, Marc Pienaar, Michael J. Somers, and Ken Findlay. "Species distribution modelling of Bryde’s whales, humpback whales, southern right whales, and sperm whales in the southern African region to inform their conservation in expanding economies." PeerJ 8 (September 22, 2020): e9997. http://dx.doi.org/10.7717/peerj.9997.

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In southern African waters, information about species distribution and habitat preferences of many cetacean species is limited, despite the recent economic growth that may affect them. We determined the relative importance of eight environmental variables (bathymetry, distance to shore, slope, chlorophyll-a, salinity, eastwards sea water velocity, northwards sea water velocity and sea surface temperature) as drivers of seasonal habitat preferences of Bryde’s whales (Balaenoptera brydei), humpback whales (Megaptera novaeangliae), southern right whales (Eubalaena australis) and sperm whales (Physeter macrocephalus). Using presence only data from multiple sources, we constructed predictive species distribution models (SDMs) consisting of ensembles of seven algorithms for these species during both summer and winter. Predicted distribution for all cetaceans was high in southern Africa and, in particular, within the South African Exclusive Economic Zone (EEZ). Predictive models indicated a more pronounced seasonal variation for humpback, sperm and southern right whales than for Bryde’s whales. Southern right whales occurred closer to shore during winter, humpback whales were more likely to occur along the east coast in winter and the west coast in summer, and sperm whales were more concentrated off the shelf in winter. Our study shows that ensemble models using historical, incidental and scientific data, in conjunction with modern environmental variables, can provide baseline knowledge on important environmental drivers of cetacean distribution for conservation purposes. Results of this study can further be used to help develop marine spatial plans and identify important marine mammal areas.

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Ugbede-Ohuoba, Elizabeth, Thomas M. Okonkwo, Iro Nkama, J. I. Eze, and Samaila James. "Shelf-life Prediction Modeling and Physicochemical Changes of Canned African Giant Snail (Achachatina achatina) Based Products during Storage Using Sensory and Kinetic Data." Journal of Food Research 10, no. 2 (February 12, 2021): 11. http://dx.doi.org/10.5539/jfr.v10n2p11.

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Canned African giant snails (brine, egusi and sauce) of low acidity (pH 4.5) were produced using Thermal Death Time (TDT) techniques. Sixty cans of each product were stored for 6 months at normal temperature (30oC). The physicochemical and sensory properties of these products were evaluated monthly. And also, 28 cans of each product were equally evaluated at accelerated storage temperatures stress (50, 60, 70 & 80oC) for 6 weeks. Changes in pH and overall acceptability were described by first and second order kinetics respectively. The extent of proteolysis, peroxidase activities, and extent of fat hydrolysis i.e peroxide and thiobabituric acid values did not change significantly (P > 0.05) during storage. Regression analysis was used to fit models for Gibbs free energy of activation for physicochemical changes as a function of temperature and to predict models for overall acceptability as a function of pH. Shelf-life prediction models were fitted based on sensory and pH kinetic data. Shelf-lives of 27.6 months, 27-25 months and 18-16.8 months were estimated for snail in brine (SIB) snail in egusi (SES) and snail in sauce (SIS) respectively during storage at 30OC.

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Manyilizu, Majuto, Philip Sagero, Issufo Halo, and Shigalla B. Mahongo. "A comparative study of ocean surface interannual variability in Northern Tanzania and the Northern Kenya Bank." Western Indian Ocean Journal of Marine Science, no. 1/2020 (February 11, 2021): 1–8. http://dx.doi.org/10.4314/wiojms.si2020.1.1.

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The livelihoods of most residents of Tanga (Northern Tanzania) and Malindi (Northern Kenya), rely strongly on fishing activities in the East African shelf region. Thus, understanding variations in sea surface temperature (SST) and its related parameters such as thermocline depths and upper ocean circulation are crucial. This study applies a regional model to understand interannual spatial relationships between ocean circulation and SST off Northern Tanzania and on the Northern Kenya Bank. The results indicate slight differences in variations off the Northern Tanzanian shelf region and the Northern Kenya Bank. Such small variations might have local impacts on the human population through influencing primary productivity and fisheries. The coastal waters off Malindi indicate stronger variations, particularly in 1997 (cold SST) and 1998 (warm SST), than those off Tanga region. The SST anomalies seem to be associated with thermocline and sea surface height (SSH) off Malindi, while off Tanga they relate only to SSH. This information provides further understanding of parameters that may affect fishing activities in these regions and can be used for planning and management processes.

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Raheem, Dele. "The Need for Agro-Allied Industries to Promote Food Security by Value Addition to Indigenous African Food Crops." Outlook on Agriculture 40, no. 4 (December 2011): 343–49. http://dx.doi.org/10.5367/oa.2011.0063.

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Food security is a major concern in developing countries and requires urgent attention and collaborative effort from all stakeholders. As the human population continues to increase, the demand for food becomes far greater than the supply can meet. There is a need to cultivate more indigenous food crops and to diversify into new products by using processing and preservation techniques to ensure that more people have access to good quality, nutritious foods. It is therefore essential that agro-allied industries in African countries receive encouragement to improve the application of technology for processing raw food crops, increasing their shelf life, improving nutritional values and packaging, and maintaining high quality standards. This paper emphasizes the potential benefits for three staple African foods – maize, cassava and sorghum. The application of science to transform the properties of these foods and relevant technologies, such as extrusion cooking, can add value to their use in the immediate future and will help in meeting the Millennium Development Goals.

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Eze, V. C., N. Maduka, I. Ahaotu, and N. N. Odu. "Microbiological Quality and Shelf Life of Pickled African Walnut (Tetracarpidium conophorum) Preserved with Lactic and Citric Acids." Microbiology Research Journal International 26, no. 1 (January 2, 2019): 1–18. http://dx.doi.org/10.9734/mrji/2018/45226.

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Waerebeek, Koen Van, Abdoulaye Djiba, Jens-Otto Krakstad, Abdellahi Samba Ould Bilal, Idrissa L. Bamy, Amadeu Almeida, and Ebou Mass Mbye. "New Evidence for a South Atlantic Stock of Humpback Whales Wintering on the Northwest African Continental Shelf." African Zoology 48, no. 1 (April 2013): 177–86. http://dx.doi.org/10.3377/004.048.0120.

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Van Waerebeek, Koen, Abdoulaye Djiba, Jens-Otto Krakstad, Abdellahi Samba Ould Bilal, Idrissa L. Bamy, Amadeu Almeida, and Ebou Mass Mbye. "New evidence for a South Atlantic stock of humpback whales wintering on the Northwest African continental shelf." African Zoology 48, no. 1 (April 2013): 177–86. http://dx.doi.org/10.1080/15627020.2013.11407581.

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Gogo, E. O., A. M. Opiyo, K. Hassenberg, Ch Ulrichs, and S. Huyskens-Keil. "Postharvest UV-C treatment for extending shelf life and improving nutritional quality of African indigenous leafy vegetables." Postharvest Biology and Technology 129 (July 2017): 107–17. http://dx.doi.org/10.1016/j.postharvbio.2017.03.019.

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47

EGEDE, EDWIN. "The Outer Limits of the Continental Shelf: African States and the 1982 Law of the Sea Convention." Ocean Development & International Law 35, no. 2 (April 2004): 157–78. http://dx.doi.org/10.1080/00908320490434266.

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Kumar, Pushpendra, Vijay Kumar, and Deepak Kumar. "Response of INM to Plant growth, Flower yield and Shelf life of African marigold (Tagetes erecta L.) cv. Pusa Basanti Gainda." International Journal of Agricultural Invention 1, no. 01 (June 30, 2016): 108–12. http://dx.doi.org/10.46492/ijai/2016.1.1.19.

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The present investigation entitled “Effect of Integrated nutrient management (INM) on Plant growth, Flower yield and shelf life of African Marigold (Tagetes erecta L.) c.v. Pusa basanti” , was under taken at department of horticulture, during the year 2013-14. The experiment was laid out in randomized block design with 13 treatments replicated thrice. The treatments comprised of FYM, vermicompost, poultry manure and bio- fertilizer (Azotobacter) with 25% RDF, 50% RDF and 75% RDF in different combinations including control (RDF). The results revealed that application of 75% RDF + 25% vermicompost (T2) produced significantly maximum plant height (76.77 cm), number of primary and secondary branches per plant (19.40, 33.47 respectively), number of leaves per plant (209.6), earliest in days to first flower bud initiation (50.07), days to first flowering (58.07) and days to 50% per cent flowering (62.87), Also number of flowers per plant (44.07), flower diameter (6.96 cm), flowering duration (54 days), average flower weight (8.52 g), flower yield per plant (375.42 g) and flower yield per plot (3.51 kg), flower yield per hectare (16.65 t) as compared to control and with application of 50% RDF + 50% vermicompost (T6) showed maximum shelf life (6.70 days) of flowers at room temperature. Economic point of view treatment T2 was found to be most economically viable in terms of gross return, net return and benefit cost ratio (2.52:1).

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SAMAAI, TOUFIEK, LIESL JANSON, and MICHELLE KELLY. "New species of Latrunculia from the Agulhas shelf, South Africa, with designation of a type species for subgenus Biannulata (Demospongiae, Poecilosclerida, Latrunculiidae)." Zootaxa 3395, no. 1 (July 23, 2012): 33. http://dx.doi.org/10.11646/zootaxa.3395.1.3.

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Three new species of Latrunculia are described from Algoa Bay, and Alphard and 45-Mile Banks, on the Agulhascontinental shelf off the southern coast of South Africa. Latrunculia gotzi sp. nov., from Alphard Banks, forms a thickraised pad with broad, low, meandering areolate porefields that are characteristically lighter in colour than the surroundingmahogany brown ectosome. Latrunculia kerwathi sp. nov., from 45-Mile Banks, forms a thin, dark greenish brownencrustation, with very small, discrete, crater-shaped porefields. Latrunculia algoaensis sp. nov., from Algoa Bay, is agreen hemisphere with relatively large, thick-lipped, circular areolate porefields. While the megascleres in these newspecies vary specifically in their dimensions, the former two species have small irregular spines on the styles. Theanisodiscorhabds of the new species also vary specifically in dimensions and degree of ornamentation, but have anundifferentiated basal whorl and manubrium, with only median and subsidiary whorls around the shaft. These are identicalin overall form to the anisodiscorhabds in several South African and New Zealand species currently recognised within thesubgenus Latrunculia (Biannulata) Samaai et al., 2006, a group of 13 species for which no type species was ever assigned. A type species is designated herein.

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Niassy, S., K. K. M. Fiaboe, H. D. Affognon, K. S. Akutse, M. C. Tanga, and S. Ekesi. "African indigenous knowledge on edible insects to guide research and policy." Journal of Insects as Food and Feed 2, no. 3 (June 15, 2016): 161–70. http://dx.doi.org/10.3920/jiff2015.0085.

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Entomophagy is an ancient practice viewed as a potential solution to food security and sustainable ecosystemmanagement in Africa. However, its expansion is challenged by several factors including acculturation, urbanisationand lack of information. Knowledge on indigenous practices can contribute to refining ongoing research activities and stimulate the development of adequate technologies to guide research, business and policy in entomophagy. We documented indigenous practices using outcomes of an online survey conducted between 2013 and 2015 and intensive literature crowd sourcing. Edible insects are mainly collected from wild harvesting using different methods. Although respondents acknowledged the existence of rearing technologies, no comprehensive procedure wasdescribed. We found that after collection, the processing techniques for either consumption or commercialisation varied. Our survey revealed that sun drying was the most commonly used processing technique probably because it does not require much input as compared to frying, boiling or roasting. Processing techniques such as boilingseem not only to reduce the amounts of toxic phytochemicals found on insects but also to eliminate some pathogenswhich can contaminate the insects during collection. To improve shelf life, certain additives such as salt, palm oil or pure honey were used to preserve the dried insects. The findings from this study are discussed from research policy and business perspective.

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Journal articles on the topic 'African Shelf'

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