Pub Date : 2024-01-30DOI: 10.17159/sajs.2024/17065
Sarah Wurz
{"title":"Becoming human: Expert sequential and flexible thinking led to cumulative culture","authors":"Sarah Wurz","doi":"10.17159/sajs.2024/17065","DOIUrl":"https://doi.org/10.17159/sajs.2024/17065","url":null,"abstract":"","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140484625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/15882
B. Otunola, M. P. Aghoghovwia, M. Thwala, O. Ololade
Fast-paced global industrialisation due to population growth poses negative environmental implications, such as pollution by heavy metals. We assessed the application of vetiver grass assisted by clay minerals for the remediation of soil and water contaminated by multiple metals in a mesocosm study. The technique was tested previously in a greenhouse study that confirmed the effectiveness of 2.5% (w/w) attapulgite and 2.5% (w/v) bentonite to improve vetiver grass remediation of soil and water contaminated by multiple metals. At the end of the experiment, the total accumulation of Co, Cr, Cu, Ni and Zn by vetiver grass from the soil was 1.8, 38.1, 19.0, 7.2 and 55.4 mg/kg, respectively, while in water, the total metal accumulation of Al and Mn by vetiver grass was 4534.5 and 104.5 mg/kg, respectively. The results confirm the effectiveness of attapulgite and bentonite as amendments to improve the remediation potential of vetiver in soil and water under natural conditions. Metal accumulation was generally higher in the roots than in shoots. We found the removal efficiency in the soil to be in the order Zn > Cr > Cu > Ni > Co and Al > Mn in water. Results also demonstrated that heavy metal accumulation was even better under natural conditions than in the greenhouse study. For example, Zn accumulation increased from 0.4 mg/kg in the greenhouse study to 55.4 mg/kg in the outdoor study. This study validates the application of bentonite and attapulgite-assisted phytoremediation for heavy metal contaminated soil and water.
{"title":"A mesocosm study on the use of clay minerals to improve heavy metal phytoremediation capacity of vetiver grass (Chrysopogon zizanioides L. Roberty)","authors":"B. Otunola, M. P. Aghoghovwia, M. Thwala, O. Ololade","doi":"10.17159/sajs.2023/15882","DOIUrl":"https://doi.org/10.17159/sajs.2023/15882","url":null,"abstract":"Fast-paced global industrialisation due to population growth poses negative environmental implications, such as pollution by heavy metals. We assessed the application of vetiver grass assisted by clay minerals for the remediation of soil and water contaminated by multiple metals in a mesocosm study. The technique was tested previously in a greenhouse study that confirmed the effectiveness of 2.5% (w/w) attapulgite and 2.5% (w/v) bentonite to improve vetiver grass remediation of soil and water contaminated by multiple metals. At the end of the experiment, the total accumulation of Co, Cr, Cu, Ni and Zn by vetiver grass from the soil was 1.8, 38.1, 19.0, 7.2 and 55.4 mg/kg, respectively, while in water, the total metal accumulation of Al and Mn by vetiver grass was 4534.5 and 104.5 mg/kg, respectively. The results confirm the effectiveness of attapulgite and bentonite as amendments to improve the remediation potential of vetiver in soil and water under natural conditions. Metal accumulation was generally higher in the roots than in shoots. We found the removal efficiency in the soil to be in the order Zn > Cr > Cu > Ni > Co and Al > Mn in water. Results also demonstrated that heavy metal accumulation was even better under natural conditions than in the greenhouse study. For example, Zn accumulation increased from 0.4 mg/kg in the greenhouse study to 55.4 mg/kg in the outdoor study. This study validates the application of bentonite and attapulgite-assisted phytoremediation for heavy metal contaminated soil and water.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139214331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/14543
M. Theron, Rina Swart, M. Londani, Charles Parry, P. P. Williams, Nadine Harker
COVID-19-related alcohol sales bans and stay-at-home orders prompted the alcohol industry in South Africa to increase their online alcohol sales promotions. We investigated changes in alcohol-related behaviour and the drivers of illegal alcohol sales through a self-reported Facebook survey that ran from July to November 2020. Questions included socio-demographics and comparison of alcohol purchasing behaviour and intake during 2019 and 2020. Statistical tests were applied to find associations between illegal alcohol purchasing and alcohol-related behaviours. A total of 792 participants took part in the survey, 69.7% of whom were female. During lockdown periods, most participants (55.3%) bought alcohol illegally from illegal outlets or friends. Online alcohol-delivery marketing increased by 20 percentage points from 2019 to 2020, with participants stating that they saw a lot of advertisements per day and 80% of persons under 25 years were not asked to verify their age in 2020 upon delivery. Home-brewed beer and vodka intake increased in 2020 during the alcohol sales bans. Men from the Western Cape who engaged in daily or weekly heavy episodic drinking were more prone to purchase alcohol illegally. The Western Cape, which is South Africa’s most prolific wine-producing region, had the highest odds of people buying alcohol illegally, with wine being found to be the most frequently bought alcohol online and consumed by these participants. There is a need for further research into the differences in alcohol-related behaviour affecting illegal alcohol purchasing according to income group, proximity to alcohol producers and underage alcohol sales and marketing through online applications.
{"title":"Alcohol consumption patterns, suppliers and online alcohol marketing: Before and during COVID-19 alcohol bans","authors":"M. Theron, Rina Swart, M. Londani, Charles Parry, P. P. Williams, Nadine Harker","doi":"10.17159/sajs.2023/14543","DOIUrl":"https://doi.org/10.17159/sajs.2023/14543","url":null,"abstract":"COVID-19-related alcohol sales bans and stay-at-home orders prompted the alcohol industry in South Africa to increase their online alcohol sales promotions. We investigated changes in alcohol-related behaviour and the drivers of illegal alcohol sales through a self-reported Facebook survey that ran from July to November 2020. Questions included socio-demographics and comparison of alcohol purchasing behaviour and intake during 2019 and 2020. Statistical tests were applied to find associations between illegal alcohol purchasing and alcohol-related behaviours. A total of 792 participants took part in the survey, 69.7% of whom were female. During lockdown periods, most participants (55.3%) bought alcohol illegally from illegal outlets or friends. Online alcohol-delivery marketing increased by 20 percentage points from 2019 to 2020, with participants stating that they saw a lot of advertisements per day and 80% of persons under 25 years were not asked to verify their age in 2020 upon delivery. Home-brewed beer and vodka intake increased in 2020 during the alcohol sales bans. Men from the Western Cape who engaged in daily or weekly heavy episodic drinking were more prone to purchase alcohol illegally. The Western Cape, which is South Africa’s most prolific wine-producing region, had the highest odds of people buying alcohol illegally, with wine being found to be the most frequently bought alcohol online and consumed by these participants. There is a need for further research into the differences in alcohol-related behaviour affecting illegal alcohol purchasing according to income group, proximity to alcohol producers and underage alcohol sales and marketing through online applications.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139214544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/14509
Basma M. Atallah, Soliman A. Haroun, E. El-Mohsnawy
Increasingly high levels of multidrug-resistant (MDR) pathogens have necessitated the discovery of novel bioactive compounds. For this reason, two actinomycetes strains, Streptomyces griseorubens and Streptomyces rochei, were isolated for the first time from the black sand shores of Kafr El Sheikh in Egypt, which is home to several large fish farms. Isolates were identified via phenotypic, biochemical and 16S rRNA sequence protocols. Both strains exhibited powerful antimicrobial activity against three serious MDR pathogens: Bacillus subtilis, Salmonella enteritidis and Pseudomonas aeruginosa. The bioactive compounds of isolates’ filtrates were identified using gas chromatography–mass spectroscopy (GC-MS). For S. griseorubens, the detectable antibacterial compounds were hexanoic acid, 2-ethyl-, 2-ethylhexyl ester, n-Decane, hexadecanoic acid methyl ester, benzene acetic acid, ricinolic acid, and ethylparaben, while S. rochei secretes heptadecane, 2,6-dimethyl-, benzene acetic acid, dibutyl phthalate, octacosane, hexacosane, and vitamin A aldehyde. These results strongly encourage the use of these eco-friendly isolates as a biocontrol against MDR pathogens that attack fish farms.
耐多药（MDR）病原体的数量越来越多，因此有必要发现新型生物活性化合物。为此，我们首次从埃及 Kafr El Sheikh 的黑沙海岸分离出两株放线菌--Streptomyces griseorubens 和 Streptomyces rochei，该海岸是几个大型养鱼场的所在地。通过表型、生化和 16S rRNA 序列协议对分离物进行了鉴定。这两种菌株对三种严重的 MDR 病原体都表现出强大的抗菌活性：枯草芽孢杆菌、肠炎沙门氏菌和铜绿假单胞菌。利用气相色谱-质谱（GC-MS）对分离物滤液中的生物活性化合物进行了鉴定。对于 S. griseorubens，可检测到的抗菌化合物有己酸、2-乙基-、2-乙基己基酯、正癸烷、十六烷酸甲酯、苯乙酸、蓖麻醇酸和尼泊金乙酯；而 S. rochei 则分泌七烷烃、2,6-二甲基-、苯乙酸、邻苯二甲酸二丁酯、二十八烷、六烷和维生素 A 醛。这些结果强烈鼓励使用这些生态友好型分离物作为生物防治手段，以对抗侵袭养鱼场的 MDR 病原体。
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Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/15853
Larisse Prinsen
Consent
同意书
{"title":"Reconsidering consent for biomedical research using human biological material and associated data","authors":"Larisse Prinsen","doi":"10.17159/sajs.2023/15853","DOIUrl":"https://doi.org/10.17159/sajs.2023/15853","url":null,"abstract":"Consent","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139209387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/16081
C. Marean
and how did hominins position themselves relative to it? Modern human hunter–gatherers always place their campsites near water – it structures much of their movement. What animals were the primary predators of hominins and how did hominins avoid them? The theory of landscape of fear shows us how important this question is. Do the faunal data show us what edible plants were available, and how these changed over time? We have become very good at assigning fossils to taxonomic groups and dating them, but we have yet to really make headway into understanding what these past ecologies were like. Second, the book shows us that we have reached a glass ceiling with our current approach. Our current approach finds fossils, describes them, dates them, and then uses specific animals or groups to infer what the environment was around the site. If there is a sequence, then we might describe how that changes over time, juxtapose it against a long climate and environmental archive record, and look for correlations. We are still very much in an inductive phase of science, and most sciences eventually mature into more deductive forms where the data are used to test hypotheses. We now have the ability to begin to do this. Advances in our ability to create climate models, and environmental models from those, has exploded in the last 10 years and will become increasingly powerful. My recommendation, which we have argued for elsewhere 3 , is that we start to nudge ourselves in that direction. In such a procedure, we would create formal models of climate and environment across regions, and then use our fragmented sequences to test and refine those models, thus creating palaeoscape models. Within those palaeoscapes, we can use computer simulations such as agent-based modelling to experiment with interactions between fauna and their environment, which of course moves us truly in the direction of palaeoecology.
{"title":"The next steps in human evolutionary palaeoecology","authors":"C. Marean","doi":"10.17159/sajs.2023/16081","DOIUrl":"https://doi.org/10.17159/sajs.2023/16081","url":null,"abstract":"and how did hominins position themselves relative to it? Modern human hunter–gatherers always place their campsites near water – it structures much of their movement. What animals were the primary predators of hominins and how did hominins avoid them? The theory of landscape of fear shows us how important this question is. Do the faunal data show us what edible plants were available, and how these changed over time? We have become very good at assigning fossils to taxonomic groups and dating them, but we have yet to really make headway into understanding what these past ecologies were like. Second, the book shows us that we have reached a glass ceiling with our current approach. Our current approach finds fossils, describes them, dates them, and then uses specific animals or groups to infer what the environment was around the site. If there is a sequence, then we might describe how that changes over time, juxtapose it against a long climate and environmental archive record, and look for correlations. We are still very much in an inductive phase of science, and most sciences eventually mature into more deductive forms where the data are used to test hypotheses. We now have the ability to begin to do this. Advances in our ability to create climate models, and environmental models from those, has exploded in the last 10 years and will become increasingly powerful. My recommendation, which we have argued for elsewhere 3 , is that we start to nudge ourselves in that direction. In such a procedure, we would create formal models of climate and environment across regions, and then use our fragmented sequences to test and refine those models, thus creating palaeoscape models. Within those palaeoscapes, we can use computer simulations such as agent-based modelling to experiment with interactions between fauna and their environment, which of course moves us truly in the direction of palaeoecology.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139209860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/14175
Alec Mlambo, Mcebisi Maphosa
In-vitro culture of mycorrhizal mushroom (MM) species in southern Africa remains largely unexplored, particularly using tree-derived media. In this study, a Julbernardia globiflora [(Benth.) Troupin] leaf infusion was tested for its ability to promote MM mycelial growth. Amanita loosii, Cantharellus miomboensis and Cantharellus heinemannianus isolates were incubated at a pH of 2, 3, 4, 5, 6 or 7 and at 25 °C in six leaf extract agar (LEA) infusion concentrations of 150, 175, 200, 225 or 250 grams of leaves/L distilled water, with potato dextrose agar (PDA) as a standard. We determined mycelium growth rates for all treatment combinations. Mycelium growth rate was found to be optimal at a pH between 4 and 6 in all leaf infusion concentrations tested. Significant (p<0.001) linear regressions of A. loosii and C. miomboensis were found for pH only (R2=0.837 and 0.8582, respectively) and a significant (p<0.001) regression was found for C. heinemannianus (R2=0.293). Amanita loosii and C. heinemannianus had faster (p<0.001) growth in PDA than in LEA, while C. miomboensis had similar growth rates in the two media. Growth characteristics observed were attributed to acid phosphatase mediated physiological processes in mycelium for the different MM species with an optimum pH of 4–6. MM mycelia were white, mycelia for A. loosii and C. miomboensis were loose and for C. heinemannianus were thin filaments. LEA proved to be a potential alternative medium for culturing MM species.
南部非洲菌根蘑菇（MM）物种的体外培养在很大程度上仍未得到探索，尤其是使用源自树木的培养基。在这项研究中，我们测试了球茎蘑菇（Julbernardia globiflora [(Benth.) Troupin]）叶片浸泡液促进菌根蘑菇菌丝生长的能力。将 Amanita loosii、Cantharellus miomboensis 和 Cantharellus heinemannianus 分离物分别置于 pH 值为 2、3、4、5、6 或 7 和 25 °C 的六种叶提取物琼脂（LEA）浸泡液（浓度分别为 150、175、200、225 或 250 克叶子/升蒸馏水）中培养，并以马铃薯葡萄糖琼脂（PDA）为标准。我们测定了所有处理组合的菌丝生长率。在所有测试的叶片浸泡浓度中，菌丝生长率在 pH 值介于 4 和 6 之间时最佳。发现 A. loosii 和 C. miomboensis 仅对 pH 值有显著的线性回归（P<0.001）（R2 分别为 0.837 和 0.8582），C. heinemannianus 有显著的回归（P<0.001）（R2=0.293）。Amanita loosii 和 C. heinemannianus 在 PDA 中的生长速度（p<0.001）快于在 LEA 中的生长速度，而 C. miomboensis 在两种培养基中的生长速度相似。观察到的生长特征归因于不同 MM 种类菌丝中酸性磷酸酶介导的生理过程，其最佳 pH 值为 4-6。MM 菌丝呈白色，A. loosii 和 C. miomboensis 菌丝松散，C. heinemannianus 菌丝细长。LEA 被证明是培养 MM 菌种的潜在替代培养基。
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Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/16217
Matthew G Adair, Jean-Jacque Forgus, Devon C. Main, J. Taft, J. D. da Silva, K. Tolley
In biodiversity research, the retrieval of genetic material from organisms is a common and essential component for assessing genetic diversity. The welfare of the organism, however, needs to be balanced against the overall goal of the intended research. One sampling technique often applied to retrieve DNA material from small reptiles is the removal of a small portion of the distal end of the tail. While most squamate reptiles have tail autotomy, some species (e.g. many iguanid lizards and snakes) do not regenerate tail tissue. We therefore explored the efficacy of a minimally disruptive technique, buccal swabbing, as an alternative to tissue sampling via tail clipping, particularly for species without tail autotomy, using dwarf chameleons (Bradypodion spp.) as a case study. The two sampling techniques were compared to assess the efficacy of DNA retrieval. We also evaluated the financial implications of each technique. The results indicate that buccal swabs paired with a specialised DNA extraction kit offer a feasible (although expensive), once-off alternative to tissue sampling, but with no material left for biobanking. Deviations in swab type used and the DNA extraction process (i.e. using more affordable extraction procedures) resulted in poor DNA retrieval and unreadable sequences. This finding suggests that buccal swabbing can be a suitable alternative when finances are not constrained, an expensive extraction kit is available, and biobanking is not a concern. For researchers from low- to middle-income economies, this expensive alternative may hamper research progress by placing a financial obstacle in the way, and therefore the next best option is tissue sampling.
在生物多样性研究中，从生物体中获取遗传物质是评估遗传多样性的一个常见且重要的组成部分。然而，生物的福利需要与预期研究的总体目标相平衡。从小型爬行动物身上提取 DNA 材料经常采用的一种取样技术是切除尾巴远端的一小部分。虽然大多数有鳞类爬行动物都有尾部自体切除术，但有些物种（如许多巨蜥和蛇）的尾部组织不会再生。因此，我们以侏儒变色龙（Bradypodion spp.）我们对两种取样技术进行了比较，以评估 DNA 提取的效果。我们还评估了每种技术的财务影响。结果表明，颊拭子与专门的 DNA 提取试剂盒配对使用，是一种可行的一次性组织取样替代方法（尽管价格昂贵），但不会留下任何材料用于生物库。咽拭子类型和 DNA 提取过程的偏差（即使用更经济的提取程序）导致 DNA 提取效果不佳，序列无法读取。这一研究结果表明，当资金不紧张、有昂贵的提取试剂盒且不担心生物库问题时，颊拭子法不失为一种合适的替代方法。对于来自中低收入经济体的研究人员来说，这种昂贵的替代方法可能会因经济障碍而阻碍研究进展，因此下一个最佳选择是组织采样。
{"title":"The pros and cons of buccal swabbing and tail clipping for monitoring reptilian biodiversity","authors":"Matthew G Adair, Jean-Jacque Forgus, Devon C. Main, J. Taft, J. D. da Silva, K. Tolley","doi":"10.17159/sajs.2023/16217","DOIUrl":"https://doi.org/10.17159/sajs.2023/16217","url":null,"abstract":"In biodiversity research, the retrieval of genetic material from organisms is a common and essential component for assessing genetic diversity. The welfare of the organism, however, needs to be balanced against the overall goal of the intended research. One sampling technique often applied to retrieve DNA material from small reptiles is the removal of a small portion of the distal end of the tail. While most squamate reptiles have tail autotomy, some species (e.g. many iguanid lizards and snakes) do not regenerate tail tissue. We therefore explored the efficacy of a minimally disruptive technique, buccal swabbing, as an alternative to tissue sampling via tail clipping, particularly for species without tail autotomy, using dwarf chameleons (Bradypodion spp.) as a case study. The two sampling techniques were compared to assess the efficacy of DNA retrieval. We also evaluated the financial implications of each technique. The results indicate that buccal swabs paired with a specialised DNA extraction kit offer a feasible (although expensive), once-off alternative to tissue sampling, but with no material left for biobanking. Deviations in swab type used and the DNA extraction process (i.e. using more affordable extraction procedures) resulted in poor DNA retrieval and unreadable sequences. This finding suggests that buccal swabbing can be a suitable alternative when finances are not constrained, an expensive extraction kit is available, and biobanking is not a concern. For researchers from low- to middle-income economies, this expensive alternative may hamper research progress by placing a financial obstacle in the way, and therefore the next best option is tissue sampling.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139210409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-29DOI: 10.17159/sajs.2023/15505
Stephen Woodborne, Duncan Miller, M. Evans, H. Cawthra, Stephan Winkler
We report radiocarbon dates obtained from on-shore marine and near-shore terrestrial deposits near Yzerfontein, on the West Coast of South Africa. These deposits include Late Pleistocene shell concretions from the southern end of 16 Mile Beach and a marine shell deposit inland of the coastal Rooipan (Red Pan); mid-Holocene coastal pan deposits exposed by modern storm erosion of the sandy 16 Mile Beach; and four Holocene storm beach deposits on a rocky shore to the south. We interpret the results in terms of local geomorphology constraints on sea-level fluctuations. The eastern margin of Rooipan is a >40 ka elevated beach deposit in a dune cordon that separates it from the adjacent Yzerfonteinpan. Both pans have gypsum deposits up to 2 m thick formed by repeated marine overwash. Saline pan deposits that are exposed intermittently on the beach are mid-Holocene and indicate a former westward extension of Rooipan. This is in contrast to storm beaches dating 8000–2600 cal BP at higher elevations on a rocky platform further south. This suggests that a dune barrier existed seaward of the present shoreline near Rooipan at this time. The coastal changes described here show that deposition and erosion can be affected significantly by the local palaeogeomorphology and cannot be ascribed solely to sea-level change.
{"title":"Radiocarbon-dated evidence for Late Pleistocene and Holocene coastal change at Yzerfontein, Western Cape, South Africa","authors":"Stephen Woodborne, Duncan Miller, M. Evans, H. Cawthra, Stephan Winkler","doi":"10.17159/sajs.2023/15505","DOIUrl":"https://doi.org/10.17159/sajs.2023/15505","url":null,"abstract":"We report radiocarbon dates obtained from on-shore marine and near-shore terrestrial deposits near Yzerfontein, on the West Coast of South Africa. These deposits include Late Pleistocene shell concretions from the southern end of 16 Mile Beach and a marine shell deposit inland of the coastal Rooipan (Red Pan); mid-Holocene coastal pan deposits exposed by modern storm erosion of the sandy 16 Mile Beach; and four Holocene storm beach deposits on a rocky shore to the south. We interpret the results in terms of local geomorphology constraints on sea-level fluctuations. The eastern margin of Rooipan is a >40 ka elevated beach deposit in a dune cordon that separates it from the adjacent Yzerfonteinpan. Both pans have gypsum deposits up to 2 m thick formed by repeated marine overwash. Saline pan deposits that are exposed intermittently on the beach are mid-Holocene and indicate a former westward extension of Rooipan. This is in contrast to storm beaches dating 8000–2600 cal BP at higher elevations on a rocky platform further south. This suggests that a dune barrier existed seaward of the present shoreline near Rooipan at this time. The coastal changes described here show that deposition and erosion can be affected significantly by the local palaeogeomorphology and cannot be ascribed solely to sea-level change.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2023-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139212163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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