The objective for this study was to provide the insight into the link between benthic foraminiferal assemblages and the surrounding environment. Stained sediment samples were collected from the continental shelf and slope off the southwest Taiwan, including the Kao-ping Submarine Canyon. In addition to faunal census, total organic carbon (TOC), carbonate, and coarse fraction of the sediments were also measured. Nevertheless, the downcore record of the excess 210Pb from selected sites offers the constraint for stratigraphy time frame for discussion. The benthic foraminiferal assemblages were analyzed by statistics. Clusters analysis shows that all species present in this study could be divided into two groupings. One is those distributed in outer shelf and the other is those found in the inner shelf of the southwest Taiwan. Different from previous studies, the spatial distribution of stained benthic foraminifera seems not to be related with TOC contents in the sediment and water depth. Both the diversity index and Eqitability show that sites inside of the canyon have lower values. The higher Living/Total ratios and lower dead tests at the head of Kao-ping Submarine Canyon than adjacent area might be the effect of migration. Furthermore, the species within the canyon are similar to the southern and northern continental shelf. These findings indicate that the spatial distribution of benthic forams within canyon might be the effect of transport, which could result from the complex interaction between tides and currents. Augmented with the profiles of excess 210Pb, the temporal variation of benthic foraminifera was revealed. Generally there is a progressive decrease in the abundance of Ammonia sp.. It is possible that the diminishing trend was caused by the increase of anthropogenic activity for the last 30 years.

The interaction between the submarine canyon topography and coastal current has very important influence on the flow field around the canyon. This study aims to understand the nature of the interaction and the associated dynamic around the Kao-ping Submarine Canyon in southern Taiwan. In 2000 and 2002 year during the flood season of the Kao-ping River, moored instruments were deployed in the Kao-ping Submarine Canyon, Kao-ping River mouth, and Kao-ping shelf for one month. The results revealed sea surface fluctuations were dominated by the tide. The sea surface fluctuations at Kao-ping River mouth and Liu-Chiu Yu Island belong to mixed tide with diurnal dominance. But the sea surface fluctuations on the shelf belong to mixed tide is having by semi-diurnal dominance. The current fields of the shelf and canyon both are dominated by semi-diurnal tide. The energy of tidal current is stronger with increasing canyon depths. Results of harmonic analysis show that the current field of canyon bottom layer and on the shelf both is dominated by the M2 component. The variation of temperature field is regulated by tidal currents. During floods, shelf flow is northwestward and the current of canyon bottom layer flow downcanyon. During ebbs, shelf flow is southeastward and the current of canyon bottom layer flow upcanyon. The interaction between the temperature field of submarine canyon and shelf is pronounced. The tidal fluctuation of temperature field on shelf is especially conspicuous during spring tide. When temperature decreases in the submarine canyon, the shelf temperature begins to decline. When temperature increases in the submarine canyon, the shelf temperature begins to arise. The results of harmonic analysis reveal that the temperature field of the canyon leads that of the shelf around 2.08 hours. The current field of bottom layer in the canyon flows towards the canyon head during ebb tides. It brings the colder and deeper water to canyon head along the canyon axis. The colder and deeper water causes the water temperature to decrease in the canyon and on the shelf. During flood tides, the colder and deeper water withdraw from the canyon head region, which makes the shelf temperature increase. The currents on the Kao-ping shelf both are largely alongshore in 2000 and 2002 observations. The alongshore mean current is northwestward. The current velocity of surface layer is greater than that of the bottom layer. In Kao-ping Submarine Canyon, the mean current of bottom layer at 195m and 245m flows in opposite directions. It flows downcanyon offshore at 195m and upcanyon at 245m. The current velocity of 245m is greater than 195m. Mean current flow of bottom layer is downcanyon along canyon axis at 280m in 2002 year. During the transition between ebb tide and flood tide, temperature fields of canyon and shelf show trend reversal. Submarine canyons play an important role in transport deeper and colder water. The interaction of canyon and shelf current field can influence the variation of shelf temperature. The tidal current velocity is stronger in spring tide. It is easier to make deeper and colder water to ascend to the shelf. The influence of current is more noticeable to adjust on the shelf and canyon temperature fields during the spring tide. The results of scale analysis show the canyon topography can influence coastal current when the radius deformation of the canyon is smaller than the canyon width. The canyon current will produce phenomena of upwelling and down-welling with tidal periods. This seems match Klink¡¦s¡]1996¡^model results.

Abstract The carbon and oxygen isotopes of planktonic foraminifera, faunal assemblage, and coarse fraction of trap materials were analyzed in this study. The sediment traps were deployed in two lacations. One was in the Kao-ping submarine canyon and the other was in the northern South China Sea. Variations of the individual concentrations from Kao-ping submarine canyon are small throughout the deployment interval except for the period when the Typhoon Chi-Te invaded southern Taiwan in July 2000. The results that benthic foraminifer abundances (#/g) are higher than that of planktonic foraminifera after typhoon invasion reflect the influence of particle settling by lateral transport. In addition, the major planktonic foraminifera found in canyon are Globigerinoides aequilateralis, Globigerinoides ruber, Globigerinoides sacculifer, and Neogloboquadrina dutertrei. At the same time, we also found Globigerina bulloides that usually lives in the high latitudes and cold temperature. It reveals the effect of nutrient supply along coastal region. The coarse fraction contents and foraminiferal abundances collected by the traps in the northern South China Sea are both increasing in January and March. It could be associated with the enhanced surface productivity. The planktonic foraminifera divided into two groups based on their preferrence. The G. bulloides and N. dutertrei live in cold environment while G. aequilateralis, G. ruber, G. sacculifer, and Pulleniatina obliquiloculata preferr warm areas. In this study, G. bulloides and N. dutertrei were found in January whereas G. aequilateralis, G. rubber, G. sacculifer, and P. obliquiloculata were mostly in March. The difference of carbon isotopes of planktonic foraminifera between species are distinct. Orbulina universa is the heaviest and G. ruber was the lightest. Foraminiferal d18O are depleted in October and enriched in January and March. It is suggested that sea surface temperature might be responsible for the variations of planktonic foraminiferal oxygen isotopes. Comparisons of foraminiferal d18O with the hydrographic data provide some informations. The results show that G. ruber lives in shallow water (~10m), G. sacculifer lives in 25m on average, and O. universa lives in deeper water layer (~70m) in northern South China Sea. Moreover, both the carbon isotopes and foraminiferal abundance of G. ruber show a negative correlation with the particles fluxes.