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Taiwan Strait Transportation (TST) Corridor
Published in Ronald C. Chaney, Marine Geology and Geotechnology of the South China Sea and Taiwan Strait, 2020
In general, sea-floor sediments are predominantly depositional rather than erosional. As a consequence, marine sediments exhibit more uniformity than normally found on land. Typically, marine sediments are broadly classified by whether the sediments are land derived (terrigenous) or are the result of marine activity (pelagic). The pelagic sediments can be further divided into inorganic or organic materials. Inorganic pelagic materials are typically clay-size material. In contrast, organic materials are primarily the skeletal remains of marine organisms. These materials are either calcium carbonate (CaCO3) or silica (SiO2). The presence of calcium carbonate in marine sediments is influenced by biological productivity and the calcium carbonate compensation depth.
The offshore environment
Published in White David, Cassidy Mark, Offshore Geotechnical Engineering, 2017
Marine sediments are composed of detrital material from land or from the remains of marine organisms, which leads to the principal classification of sediment as either terrigenous (transported from land) or pelagic (sediments that settle through the water column). Pelagic sediments are deposited so slowly that nearshore and coastal areas are overwhelmed by terrigenous deposits.
Spatial Distribution and Contamination Assessment of Trace Metals in the Coral Reef Sediments of Kavaratti Island in Lakshadweep Archipelago, Indian Ocean
Published in Soil and Sediment Contamination: An International Journal, 2020
Anu Joy, P P Anoop, R Rajesh, Angel Mathew, Anu Gopinath
Marine sediments can act as potential sinks and provenance of pollutants and contaminants in the aquatic environment because of their set up of variable lithogenic, mineralogical and chemical properties. In aquatic environments, many metals are transported predominantly in association with particulate matter, which makes sediments, the most important repository for metal pollutants that enter the water bodies (Ridgway and Shimmield 2002). Therefore, metal pollution in the marine sediments has become a major environmental problem because it threatens the economic and ecological value of the coastal area (Qian et al. 2015). Sediment total metal analysis have been used frequently in the initial phase of environmental assessment to locate areas of possible concern and trace historical changes because they give an integrated picture of contaminants over time.
Remediation of metal-contaminated marine sediments using active capping with limestone, steel slag, and activated carbon: a laboratory experiment
Published in Environmental Technology, 2019
Seong-Jik Park, Ku Kang, Chang-Gu Lee, Jae-Woo Choi
The most widely used remediation technologies for contaminated marine sediments are bioremediation, dredging/disposal, and in situ capping. Bioremediation is categorized into monitored natural recovery (MNR), biostimulation, bioaugmentation, and phytoremediation. In MNR, the degradation of contaminants in sediments is naturally achieved by indigenous microbial populations. Although this method has an advantage of not causing adverse effects on the ecosystem, it requires a long time for purification under the prevention of contaminant inflow [1]. Bioremediation is a more active method of remediating contaminated sediments because it encourages the growth of indigenous populations by the input of nutrients or air (biostimulation), and it introduces appropriate species from external environments (bioaugmentation) by using plants and algae for the removal of contaminants [2]. Dredging/disposal can completely remove the contaminated sediments, although it is the most expensive technique for their remediation [3]. Dredging/disposal requires a site and further management to depose of dredged sediment and has other negative effects on the environment through resuspension of particulates and destruction of the benthic community during the dredging process [4–6]. Capping contaminated sediments is an in situ remediation technique that consists of covering the contaminated sediment surface with clean material [2]. Capping is typically less expensive than dredging/disposal, and it isolates the contaminated sediments, which blocks the diffusion of contaminants in the short term [2,7,8].
The physical model with temperature and pressure controlled for measuring acoustic velocity of marine sediments
Published in Marine Georesources & Geotechnology, 2019
Jianping Zhou, Chunhui Tao, Hongxing Li, Xianglong Jin, Lei Qiu, Guoyin Zhang, Xianming Deng
Marine sediment is an important boundary layer to marine acoustics, ocean engineering and marine geology. The environment of the seabed in terms of temperature and pressure has a significant effect on the acoustic properties of the near-bottom sediment. The proposed pilot system will be a perfect platform to measure the acoustic properties of samples under controlled temperature and pressure. Theoretical and experimental results show that the acoustic properties of samples can be easily obtained in the pilot system. In addition, using the system, one can change the measuring frequency while maintaining the temperature and pressure constant. In other words, the pilot system can be used in the laboratory to study the relationship between the acoustic properties of a sample and the variations of temperature and pressure.