The depositional history of the Knysna estuary since European colonization in the context of sea level and human impacts

Frontiers in Ecology and Evolution

Ecology and Evolution

Marco Aquino-López¹  Yakhuluntu Dubazana²  Helen G. Antonopoulos²  Rieneke Weij³  Kelly L. Kirsten³  Lauren Pretorius⁴  Jemma Finch⁴  Abdul Qadeer⁵  Michael E. Meadows⁶  Kunshan Bao⁷ 

[1] Centro de Investigacion en Matemáticas, Guanajuato, Mexico;Department of Environmental and Geographical Science, University of Cape Town, Rondebosch, South Africa;Department of Geological Sciences, University of Cape Town, Rondebosch, South Africa;Human Evolution Research Institute, University of Cape Town, Rondebosch, South Africa;Discipline of Geography, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa;National Engineering Laboratory for Lake Pollution Control and Ecological Restoration, State Environmental Protection Key Laboratory of Drinking Water Source Protection, Chinese Research Academy of Environmental Sciences, Beijing, China;School of Geography and Ocean Sciences, Nanjing University, Nanjing, China;Department of Environmental and Geographical Science, University of Cape Town, Rondebosch, South Africa;School of Geography, South China Normal University, Guangzhou, China;

关键词: pb;    C;    grain size;    magnetic susceptibility;    loss-on-ignition;    estuarine sediments;    human impact;    sedimentation rate;   

DOI  :  10.3389/fevo.2023.1120460

 received in 2022-12-10, accepted in 2023-04-26,  发布年份 2023

来源: Frontiers

【 摘 要 】

IntroductionEstuaries are highly vulnerable systems and increasingly exposed to a number of environmental, climatic and human-induced stressors. The Knysna estuary and lagoon complex, on the south coast of South Africa, is regarded as environmentally and economically important, yet faces regional impacts resulting from ongoing urbanisation and land use change as well as the significant global threats of rising sea levels and changing climate. Although the estuary has been reasonably well studied in terms of modern ecological processes, little is known of how the system has responded to changes in the longer term, not least the impact of European colonization and subsequent population growth and economic development.MethodsIn order to address this shortcoming, a series of shallow (<1 m) cores was extracted from a range of representative habitats and marine influences in the estuary and three of these (namely KNY-19A, KNY-19B, KNY-19G) selected for detailed analysis, including organic matter content, magnetic susceptibility, selected elemental analysis and particle size.Results and DiscussionNotwithstanding the challenges of dating estuarine sediments due to the possibility of erosion and resuspension, combined modelling of 210Pb and 14C ages is successfully deployed to develop an age-depth relationship for each core, providing a chronological framework for late Holocene environmental changes. Sedimentary characteristics of the three cores, taken in contrasting estuarine conditions, yield insights as to how different parts of the estuary responded to changes in sea level and anthropogenic activities in and around the Knysna basin, as well as in the wider catchment.

【 授权许可】

Unknown   
Copyright © 2023 Kirsten, Pretorius, Meadows, Weij, Aquino-López, Antonopoulos, Dubazana, Qadeer, Finch and Bao.