Spatio-temporal accumulation patterns of trace metals in sediments of a large plateau lake (Erhai) in Southwest China and their relationship with human activities over the past century

2022 ◽  
pp. 106943
Author(s):  
Huiji Liu ◽  
Enfeng Liu ◽  
Zhenzhen Yu ◽  
Qi Lin ◽  
Enlou Zhang ◽  
...  
Keyword(s):  
Trace Metals ◽  
Human Activities ◽  
Southwest China ◽  
Past Century ◽  
The Past ◽  
Lake Erhai ◽  
Spatio Temporal ◽  
Plateau Lake ◽  
Temporal Accumulation

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 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.

Spatio-temporal patterns of livestock anthrax in Ukraine during the past century (1913–2012)

2014 ◽  
Vol 54 ◽  
pp. 129-138 ◽  
Author(s):  
Maksym Bezymennyi ◽  
Karoun H. Bagamian ◽  
Alassane Barro ◽  
Artem Skrypnyk ◽  
Valeriy Skrypnyk ◽  
...  
Keyword(s):  
Temporal Patterns ◽  
Past Century ◽  
The Past ◽  
Spatio Temporal

scholarly journals Spatio-temporal patterns of organic carbon burial in the sediment of Lake Erhai in China during the past 100 years

2019 ◽  
Vol 31 (1) ◽  
pp. 282-292
Author(s):  
LIU Huiji ◽  
◽  
LIU Enfeng ◽  
YU Zhenzhen ◽  
ZHANG Enlou ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Temporal Patterns ◽  
The Past ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Lake Erhai ◽  
Spatio Temporal

scholarly journals The implications of disconnectivity for the study of contemporary geomorphic processes

2017 ◽  
Vol 19 (1) ◽  
pp. 5-15
Author(s):  
SLAYMAKER Olav
Keyword(s):  
Human Activities ◽  
Spatial Scales ◽  
Scale Problem ◽  
Conservation Of Mass ◽  
Natural Processes ◽  
The Past ◽  
Temporal And Spatial ◽  
Spatio Temporal ◽  
Geomorphic Processes

The emphasis on the understanding of contemporary geomorphic processes that has dominated Anglophone geomorphological literature over the past 50 years has seen huge progress but also some set-backs. We now have reliable measurements of mean rates of operation of all subaerial processes responsible for modification of landforms and landscapes and have made good progress in estimating the role of human activities as compared with “natural” processes. Some limited progress has been achieved in understanding the scale problem but problems remain. Perhaps the single most surprising development has been the recognition of the ubiquity of disconnectivity in geomorphic systems, the need to calculate virtual velocities of whole geomorphic systems and the relevance of this understanding to the general spatio-temporal scale problem. We have always known that most geomorphic processes operate intermittently but we have continued to depend on models that imply that mass and energy move freely through geomorphic systems and that conservation of mass and energy occurrs uninterruptedly at all temporal and spatial scales.

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.

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