| Summary: | 碩士 === 國立中山大學 === 海洋地質及化學研究所 === 93 === Abstract
The goal of this study is to infer the nature of suspended particles from settling, advection, and resuspension processes. Previous studies have not shown that the influence of physical and biogeochemical nature on the behavior of suspended particles. Therefore we expect to observe differential hydrodynamic behavior of suspended particles of different nature in the study. The size distribution of suspended particles is a variable of sediment transport. Size and density, which play a major role in distribution of particles through the water column, are two of primary factors in determining the settling velocity of suspended particles. The sites of the field experiments were located on the Kao-ping Shelf and Kao-ping Submarine Canyon in Southern Taiwan in order to observe resuspension and settling processes. The field experiments were conducted to deploy moored instruments at the two study sites for collecting the time series data. The experiments also included profiling of temporal and special particle and hydrographic parameters along the Kao-ping Submarine Canyon using R/V Ocean Researcher III. In this study we employed a multidisciplinary approach to the study of suspended particles on a plainer inner shelf and sinuous submarine canyon.
Base on the observations on the Kao-ping Shelf, the concentration of coarse-grained suspended particles near the bottom was greater than near the surface, and the fine-grained suspended particles was greater near the surface than the bottom. Coarse-grained suspended particles had better correlation with salinity of which nonlithogenic matters were the primary constituents. Fine-grained suspended particles, which consist mainly of lithogenic matters, were affected more by the current. Initial analysis of the data showed that local current speed controlled the distribution of different sizes particles. When strong currents were present, there were more coarse-grained suspended particles. Conversely, there were more fine-grained suspended particles.
Regarding the temporal and special observations in the Kao-ping Submarine Canyon, the concentration of suspended particles increased with depth. The compositions of suspended particles measured by LISST-100 and water samples in the submarine canyon showed opposite trends. It revealed that different methods lead to different results. The two sediment trap arrays deployed in submarine canyon were influenced by oscillatory tidal currents. In spring tide there was high concentration of settling particles, which is composed of nonlithogenic materials. Suspended particles in the lower part of the submarine canyon did not all come from the upper part of the canyon but were transported by strong tidal currents to the observed site.
The distributions of different sizes particles were the result by different hydrodynamic behavior due to nature of particles. Oscillatory tidal currents could affect the transports of suspended particles from the Kao-ping continental shelf to the Kao-ping Submarine Canyons.
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