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07/12 Lecture ----The challenge to characterize and quantify marine suspended sediment due to their diverse nature


Time: 2017-07-12 (Wednesday) 10:00-11:00
Speaker: James T. Liu, Prof.
Institution: National Sun Yat-sen University, Taiwan
Venue: C3-311, Xi Ping Bldg
Host: Xing Jian
Contact: Chen Jingyan, chenjy@xmu.edu.cn

Abstract: Sediments in estuarine and marine environments came from various terrestrial and marine sources transported by different processes, and thus, have a diverse nature. This diverse nature is reflected in their physical and geochemical properties. In the past, different methods have been used to study these sediments, including filtration of water samples; optical devises based on light transmission, diffraction and backscatterance; acoustic devises based on diffraction and backscatterance; satellite sensors; and scanning electron microscope (SEM). All these methods have their advantages and shortcomings. Based on years of experience, we developed a new method to measure the in-situ bulk density of these sediments, which is advantageous to address the physical properties of the sediment and to quantify flocculated/aggregated particles. We also recognized that because of the diverse nature of these sediments, they are always carriers of biogeochemical signals (organics, trace metals, heavy metals, etc.) through surface chemistry with dissolved chemicals in the water. This particle affinity is especially evident in fine-grained (finer than medium silt) particles. We therefore advocate that a holistic/interdisciplinary approach is needed when we address issues related to estuarine and marine sediments.