| dc.description.abstract | The Danshuei River is located in Northern Taiwan and flows through the metropolitan are of the Taipei City and the New Taipei City, the most densely populated area in Taiwan. Large amount of waste is discharged into the Danshuei River and strongly affects the concentrations of suspended organic matter and nutrients. Qualitative and quantitative analyses of suspended particulate matter can not only give us information about the biogeochemical processes, but can also help us understand the transportation process of the suspended solid in the Danshuei River.
In the past, the particulate organic matter (POM) was assumed comprising of anthropogenic wastes, soils and river sediments. However, according to previous observations, it was found that anthropogenic waste not an important source of POM. Because of the high correlation between particulate organic carbon (POC) and chlorophyll-a, we considered that phytodetritus is an important source of particulate organic matter in the Danshuei River. Thus this study defined the properties of phytodetritus and used them to represent a new end-member to calculate the contributions from different sources of POM in the Danshuei estuary. Using a three end member mixing model based on δ15NPN values and C/N ratios, we calculated the fractions from the three major sources of POM,namely, phytodetritus, soils and bed-rock derived sediments, in the estuary. Their contributions were, respectively, 45.4%, 51.8% and 2.8% in February 2009, and 75.3%, 17.3% and 7.5% in July 2009.
This study also investigated the concentrations of suspended solid in the estuarine and coastal environments. The results show that the concentrations of suspended solid derived from the measurements were affected by blanks, which may be contributed by salt or dissolve organic matter retained by the filters. It is necessary to carry out replicated measurements for the concentration of suspended solid and use linear regression to obtain the most reliable results.
It was found that, without blank correction, the correlation between gravimetric results and OBS data (R2 = 0.151, p = 0.046) is insignificant. After correction for the blanks by regression analysis, they were significantly correlated (R2= 0.568, p < 0.001), indicating the importance of regression analysis for blank correction. However, most of the OBS data are overestimated relative to the gravimetric results, indicating problems with the original setting of the OBS. Therefore, calibration of the OBS should be carried out very carefully in order to obtain optimal results in such complicated environments. | en_US |