The surface sediments off Southwestern Taiwan were collected during three different cruises in May 2009, November 2009, and March 2010, respectively. The concentrations of chlorophyll-a and phaeopigment, as well as benthic foraminifera species, were analyzed. The results show that the concentration of chlorophyll-a decreases with the distance from the shore, and the concentration of chlorophyll-a also decreases with increasing water depth. The concentration of phaeopigment seems to have no significant relationship with the water depth. The relationships between the concentrations of benthic foraminifera, chlorophyll-a, and phaeopigment are also not significant. Because samples were collected from different water depths on the continental shelf, slope and in a canyon, the oceangraphic setting therefore may be one of the main factors which influences the distribution pattern of benthic foraminifera. According to the EOF analysis, the water depth in sampling sites plays a very important role in terms of the distribution of living benthic foraminifera in this study. The distribution do not show significant difference between collecting seasons. Finally, the concentrations of the chlorophyll-a and phaeopigment decrease drastically in a downcore record. Quinqueloculina spp., an epifaunal foraminifer, shows a significant peak concentration in the depth of 5-6 cm downcore. Bioturbation probably was responsible for this change.

Glenbrook Lagoon, an 8 hectare lake receiving rainfall runoff from a residential catchment, is experiencing nutrient enrichment problems expressed as excessive aquatic plant presence. This study aims to assess the relative nutrient contribution of the total system compartments, including catchment loading, water column, aquatic plants and surface sediment. This information is utilised in the formulation of management strategies which may produce a sustainable nutrient reduction and general improvement in the system. The total nutrient content of the aquatic system was determined to be high in comparison with the present nutrient loading from the catchment. The ideal management case considers nutrient reduction of the surface sediment compartment firstly, followed by the aquatic plant community, with the water column and catchment influence as relatively low priority compartments. Various strategies for managing these are proposed. The total system benefits of the ideal management case are reductions in nutrients, aquatic plant biovolume and suspended solid loading. Unavoidable constraints placed upon the ideal management case include the excessive aquatic plant presence restricting accessability to the surface sediment for dredging. The resulting best management case requires aquatic plant eradication prior to sediment management, with the total system benefits associated with the ideal management case being retained. / Master of Science (Hons)

In the current study, sub-fossil Cladocera collected from the surface sediment of 44 shallow lakes spanning over five latitudes from north to south of Turkey using snap-shot methodology revealed strong impact of salinity on cladoceran community structure. To see the whole picture, sediment cores collected from six of the lakes and long-term monitoring data from two of the lakes were also investigated. Contemporary cladocerans and sub-fossil assemblages were compared to reveal that their responses to salinity changes were highly similar. This lead us to use sub-fossil cladocerans and salinity data from water column together while generating the calibration data set using ordination techniques. Salinity transfer function models were developed utilising weighted averaging techniques. The developed salinity transfer function was applied to cladocera assemblages from dated sediment cores. Hindcasting of the salinity inference model was performed using monitoring data and the reconstructed salinities from two central Anatolian lakes and reflected good linear correlation with the known lake salinity history. This thesis has confirmed that sub-fossil Cladocera is a valuable indicator of historical salinity change and marker for the monitoring of lakes. For the first time, the lake environmental variables and sub-fossil cladoceran species composition from the surface sediments of Turkish shallow lakes were studied and a salinity transfer function was developed to elucidate past salinity change. The approach of the current study has been proven to be reliable while interpreting past salinity conditions. Since monitoring programmes are scarce in Turkey, paleolimnological analyses would be beneficial especially when defining effective restoration strategies.