Coastal dune mobility over the past century: A global review

2020 ◽  
Vol 44 (6) ◽  
pp. 814-836 ◽  
Author(s):  
Jinjuan Gao ◽  
David M Kennedy ◽  
Teresa M Konlechner
Keyword(s):  
Human Activities ◽  
Vegetation Cover ◽  
Dominant Role ◽  
Coastal Dunes ◽  
Mediterranean Area ◽  
Global Scale ◽  
Coastal Dune ◽  
Sediment Supply ◽  
Past Century ◽  
The Past

The mobility of coastal dunes is characterised by bio-geomorphological responses related to change in boundary conditions, particularly sediment supply, wind and vegetation cover, as well as human activities. There remains uncertainty regarding the relative importance of these drivers on dune mobility at a global scale. In this study, trends and dominant drivers of coastal dune mobility are synthesised through the literature review focusing on shifts in dune mobility over the last century (1870–2018). In total, 176 individual dunes, with 55 dunes from the Europe-Mediterranean area, 23 from Africa, 30 from North America, 23 from South America, 20 from Oceania and 23 from Asia, are reviewed in this work. The results show that there is a worldwide trend of dune stabilisation, with 93% (164 out of 176) of the reviewed sites showing a loss of bare sand area due to an increase in vegetation cover and urbanisation expansion. Multiple factors have contributed to the stabilisation process, including (a) land-use change such as the change of traditional farming practises, coastal urbanisation and tourism development; (b) dune stabilisation projects; (c) sediment decline caused by the riverine and coastal constructions; and (d) change in climate (i.e. the decrease in windiness, and the increase in temperature and rainfall) and storms. Our results suggest human intervention played a dominant role in altering dune mobility for most dunes during the past century, while climate and storms are also important drivers, especially for dune sites with limited human activities.

scholarly journals Sedimentary Responses to Climate Changes and Human Activities Over the Past 7400 Years in the Western Sunda Shelf

2021 ◽  
Vol 9 ◽  
Author(s):  
Kaikai Wu ◽  
Xuefa Shi ◽  
Zhanghua Lou ◽  
Bin Wu ◽  
Jingrui Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Human Activities ◽  
Chemical Weathering ◽  
Climate Changes ◽  
Sediment Supply ◽  
Initial Time ◽  
Sunda Shelf ◽  
The Past ◽  
Terrigenous Input ◽  
Erosion Processes

High-resolution records of grain size, major and trace elements, and Sr-Nd isotopes of Core K17 from the western Sunda Shelf were investigated to evaluate the response of weathering and terrigenous input to climatic changes and human activities over the past 7400 years. Sr-Nd isotopic results indicate that the Kelantan River is the main source of sedimentary material in the study core since the mid-Holocene. Chemical weathering levels are represented by the chemical index of alteration (CIA), αAlNa, and K2O/Al2O3 ratios; and geochemical and grain size proxies (including TiO2/CaO, Rb/Sr ratios, and grain size end-member) were used to establish variations of terrigenous input into the study core since 7400 cal yr BP. Based on these records, the evolution of weathering and terrigenous input processes in the western Sunda Shelf can be divided into four stages. During stage 1 (7400–3700 cal yr BP), increasing precipitation and decreasing temperature jointly balanced the relatively stable weathering and terrigenous sediment supply. Dramatically decreasing weathering rates were consistent with less rainfall and lower temperatures during stage 2 (3700–2600 cal yr BP). Heavy rainfall played a more important role than low temperature in controlling weathering and erosion, leading to increasing terrigenous input in stage 3 (2700–1600 cal yr BP). Because of the decoupling between weathering, erosion, and climate in the late Holocene (stage 4, since 1600 cal yr BP), increasing agriculture and related human activities likely dominated weathering and erosion relative to climate changes. Furthermore, the initial time at which human activity overwhelmed natural processes in the southern South China Sea (SCS) is similar to that in the northern SCS. Our results highlight that human activities during the past 1600 years have gradually overwhelmed natural climatic controls on weathering and erosion processes in the western Sunda Shelf.

scholarly journals Human-Induced Enrichment of Potentially Toxic Elements in a Sediment Core of Lake Balkhash, the Largest Lake in Central Asia

2020 ◽  
Vol 12 (11) ◽  
pp. 4717 ◽  
Author(s):  
Kun Huang ◽  
Long Ma ◽  
Jilili Abuduwaili ◽  
Wen Liu ◽  
Gulnura Issanova ◽  
...  
Keyword(s):  
Central Asia ◽  
Sediment Core ◽  
Human Activities ◽  
Toxic Elements ◽  
Potentially Toxic Elements ◽  
Dominant Factor ◽  
Past Century ◽  
The Past ◽  
Lake Balkhash ◽  
The Impact

Over the past century, the impacts of human activities on the natural environment have continued to increase. Historic evolution of the environment under anthropogenic influences is an important reference for sustainable social development. Based on the geochemical analyses of a short sediment core of 49 cm from Lake Balkhash, the largest lake in Central Asia, potential factors historically influencing geochemical variation were revealed, and influences of human activity on regional environmental change were reconstructed over the past 150 years. The results showed that the dominant factor inducing changes in potentially toxic elements (V, Cr, Co, Ni, Zn, Cu, Cd, and Pb) is the physical weathering of the terrestrial materials. The variation in Ca content was influenced by the formation of authigenic carbonate. Since 1930, potentially toxic elements (Cr, Co, Ni, Zn, Cu, Cd, and Pb) in the lake sediments have obviously been affected by human activities, but the impact of human activities has not exceeded that of natural terrestrial weathering. In particular, the enrichment factors (EFs) for Cd and Pb reached 1.5. The average ecological risks of Cd were higher than the criterion of 30, suggesting a moderate risk to the local ecosystem in recent years. Total risk indices indicated moderate potential ecological risk for the lake ecology. The results will provide support for the environmental protection and better management practices of the Lake Balkhash watershed.

Sedimentary transition of the Yangtze subaqueous delta during the past century: Inspiration for delta response to future decline of sediment supply

2020 ◽  
Vol 428 ◽  
pp. 106279
Author(s):  
Qing Zhan ◽  
Maotian Li ◽  
Xiaoqiang Liu ◽  
Jing Chen ◽  
Zhongyuan Chen
Keyword(s):  
Sediment Supply ◽  
Past Century ◽  
The Past

scholarly journals Herpetofauna, Coastal Dunes, Buenos Aires Province, Argentina

Check List ◽  
2006 ◽  
Vol 2 (3) ◽  
pp. 15 ◽  
Author(s):  
Federico Kacoliris ◽  
Nathalie Horlent ◽  
Jorge Williams
Keyword(s):  
Habitat Loss ◽  
Human Activities ◽  
Buenos Aires ◽  
Conservation Status ◽  
Coastal Dunes ◽  
Field Work ◽  
Coastal Dune ◽  
Conservation Strategies ◽  
Buenos Aires Province ◽  
Loss Process

Coastal dunes habitats at Buenos Aires province are in a fragmentation and habitat loss process due to related human activities. Knowledge on the herpetofauna of Buenos Aires province coast habitats is plentiful for some species of lizards and scarce for most amphibians and snakes. With the aim to present a list on the amphibians and reptiles of the coastal dune habitats in Buenos Aires province we recorded species coming from field work, cited in literature, and vouchers specimens deposited in herpetological collections. We recorded 35 species in six sectors that represent the last remnants of coastal dunes in good conservation status. The Mar Chiquita and Faro Querandí Reserves represent an important contribution to the conservation of several species that inhabit coastal dune habitats. It is necessary to increase the knowledge on biodiversity in those habitats in order to develop conservation strategies.

Innovative Uses of Wave Power: Environmental Management of the Port of Ensenada, Mexico

2002 ◽  
Vol 36 (4) ◽  
pp. 74-84 ◽  
Author(s):  
Steven Czitrom ◽  
Ismael Núñez ◽  
Isabel Ramírez
Keyword(s):  
Environmental Management ◽  
Numerical Model ◽  
Water Column ◽  
Human Activities ◽  
Wave Power ◽  
Past Century ◽  
The Past ◽  
National University ◽  
Restrictive Measures ◽  
Shed Light

Over the past century, the water and sediments of the port of Ensenada, México, have accumulated a lot of pollution from human activities. Although present day restrictive measures inhibit any further accumulation, the existing aggregation in the sediments is sufficient to maintain high levels of contamination throughout the port, despite the flushing action of the tides. A SIBEO (SIBEO is an acronym for the Spanish SIstema de Bombeo por Energía de Oleaje) wave-driven seawater pump recently developed at the National University of Mexico is proposed to inject clean and oxygen rich seawater from outside the port to promote flushing in the more stagnant sections of the harbour. Results from a numerical model of the port hydrodynamics shed light on why the tides cannot on their own adequately flush the system, and how the wave-driven seawater pump will help to promote ventilation. Over the next 4 years, a cluster of SIBEO pumps is proposed to be installed on the Ensenada breakwater to inject unpolluted seawater at various locations in the port. A programme will be carried out to study the effects on the water column and sediments, in this first full-scale application of the SIBEO.

scholarly journals A 100-year record of climate change and human activities inferred from the geochemical composition of sediments in Chaiwopu Lake, arid northwest China

2016 ◽  
Author(s):  
Wen Liu ◽  
Jinglu Wu ◽  
Xiangliang Pan
Keyword(s):  
Climate Change ◽  
Human Activities ◽  
Chemical Weathering ◽  
Northwest China ◽  
Past Century ◽  
Surface Erosion ◽  
Geochemical Composition ◽  
The Past ◽  
Element Concentrations ◽  
Arid Northwest China

An 81-cm sediment core from Chaiwopu Lake in arid northwest China was analyzed for <sup>137</sup>Cs activity and concentrations of major and trace elements. We used these data to discriminate between the influence of climate change and human activities on the geochemical change of the lake sediments over the past century. Elements Al, K, Ba, Ti, V, Fe, Ni, Mn, Li, and Be were mainly from detrital. Ca, Sr, and Mg concentrations were controlled by chemical weathering processes. Na came mainly from salt precipitation caused by a decline in water level. Enrichment factors for Pb and P in recent deposits are large, indicating they were influenced by human activies. Geochemical conditions during the past century can be divided into three stages: i) From ca. 1900 to the1950s element concentrations varied widely and frequently. In general, concentrations of typical mobile elements Ca, Sr, and Mg stay relatively high whereas values for other elements remained relatively low. This was interpreted to reflect variable climate under conditions of weak surface erosion intensity. ii) From the 1950s to the early 2000s, element concentrations display less variability. The Al, K, Ba, Ti, P, Cr, V, Fe, Ni, Mn, Co, Cu, Li, Zn, Be, Pb, and Na contents were generally higher, whereas contents of Ca, Sr, and Mg were on average lower. This indicates that the regional environment was conducive to surface erosion. Enrichment of trace metals and major elements in the sediment reflects enhanced human activities. iii) In the last decade, Pb and P exhibited a great increase, possibly associated with the input from fossil fuel combustion, sewage discharge and non-point-source pollution in the watershed. The lake volume decreased substantially because of groundwater extraction for municipal water, which resulted in a marked increase in salinity and enhanced Na precipitation.

Research and Engineering Practice in Nanofluids: Key Issues

2011 ◽  
Author(s):  
L. Q. Rick Wang
Keyword(s):  
System Performance ◽  
Wave Theory ◽  
Global Scale ◽  
Constructal Theory ◽  
Engineering Practice ◽  
Past Century ◽  
Heat Transfer Fluids ◽  
The Past ◽  
Nano Structures ◽  
Key Issues

Unlike the past century that was blessed with ever-abundant cheap oil, this century energy has been rated as the single most important issue facing humanity. A global-scale energy crisis looms ahead. Nanotechnology will figure centrally in providing technological solutions. Nanofluid technology, one of the enabling technologies of the nanotech revolution, holds the promise of significantly enhancing the thermal properties of fluids and thus providing high quality heat-transfer fluids of the future that are vital for solving the terawatt challenge facing us. Nanofluids, fluid suspensions of nanometer-sized structures, are research challenges of rare potential but daunting difficulty. The potential comes from both scientific and practical opportunities in many fields. The difficulty reflects the issues related to multiscales. Nanofluids involve at least four relevant scales: the molecular scale, the microscale, the macroscale and the system-scale, with the microscale as the additional one at which nano structures interact with the base fluids. By their very nature, research and engineering practice in nanofluids are to optimize the microscale physics (structures, properties and activities) for the best system performance via enhanced macroscale properties through manipulating microscale physics. Therefore, interest should focus on addressing questions like: (i) how to optimize microscale physics for the optimal system performance, (ii) what is the macroscale manifestation of microscale physics, and (iii) how to effectively manipulate at microscale. In this keynote lecture, we summarize our work of addressing these key issues with powerful microfluidic technology, thermal-wave theory and constructal theory by taking heat-conduction nanofluids as the example.

scholarly journals TOC and Black Carbon records in sediment of Lake Yangzong, Yunnan Province under the influence of human activities during the past century

2017 ◽  
Vol 29 (4) ◽  
pp. 1018-1028 ◽  
Author(s):  
LIU Yilan ◽  
◽  
ZHANG Enlou ◽  
LIU Enfeng ◽  
WANG Rong ◽  
...  
Keyword(s):  
Black Carbon ◽  
Human Activities ◽  
Yunnan Province ◽  
Past Century ◽  
The Past
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