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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Species composition and seasonal distribution of Siphonophores in the coastal water, southwestern Taiwan.

Tung, Shu-Rung 04 September 2003 (has links)
This study is aimed to investigate the species composition and seasonal distribution of siphonophores in relation to water temperature and salinity in the coastal waters, southwestern Taiwan, from June 2001 to October 2002. In total, 39 siphonophoran species belonging to 17 genera and 5 families were identified, with the mean total abundance of 5301¡Ó8525 ind./100m3. The numerical abundance of siphonophores showed apparent seasonal change, higher in spring and autumn and lower in winter. The five most dominant species were Chelophyes contorta, Lensia subtiloides, Sulculeolaria chuni, Bassia bassensis and Diphyes bojani, and contributed to 80.2% of the total abundance of siphonophores. The mean abundance and species number of siphonophores were higher in surface water than in 0~100m oblique tow. The siphonophores found in the present study mostly belonged to the widespread oceanic species or widespread coastal species, and the dominant species were similar to those in the South China Sea. The dominant siphonophoran species exhibited apparently seasonal succession. Different dominant species showed different seasonal distribution patterns and percentage composition of sexual and asexual generations in total population. The total abundance of siphonophore showed significant (p>0.05) correlation with water salinity, but not temperature. The abundance of Chelophyes contorta, Lensia subtiloides, Abylopsis eschscholtzi and Diphyes chamissonis were significantly correlated to water temperature, but the abundance of Sulculeolaria chuni and Abylopsis tetragona showed significantly negative correlations with temperature. The abundance of Chelophyes contorta, Lensia subtiloides and Abylopsis eschscholtzi were significantly negatively correlated to salinity, but Sulculeolaria chuni showed significantly positive correlation with salinity.
2

Distribution of Living Benthic Foraminifera and Its Relationship with the Pigment Concentration in the Sediments from Coastal Region off Southwestern Taiwan

Chen, Li-Ying 15 August 2012 (has links)
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.
3

Distribution of Trace Elements (Cd, Cu, Ni, Zn) in Waters from Southwestern Coast off Taiwan

Sheu, Yen-Lin 22 August 2012 (has links)
Water samples were collected from coastal region off southwestern Taiwan during two cruises in different seasons (October, 2008 and March, 2010). In order to provide information for trace elements in this region, this study investigated the distribution and partitioning of dissolved trace elements (Cd, Cu, Ni, Zn), and to relate the influences of complicated hydrological conditions to trace element distributions. Fractionation of dissolved trace elements was applied by a one-step preconcentration technique which uses cationic and anionic exchange columns. Trace element fractions were separated to operationally defined reactive (Chelex-labile), organically complexed (anionic-organic), and stable (inert) species. Distributions of trace elements from near-shore surface waters off southwestern Taiwan were mainly affected by temporally variable terrigenous inputs and hydrological conditions. The most significant sources of trace elements were from the Gao-Ping, Er-Ren, and Tseng-Wen Rivers. Some near-shore vertical profiles of trace elements and nutrients showed abnormal distributions that could be attributed to complicated currents in this region. Trace elements in waters at offshore stations in this study showed nutrient-type distributions, and that is similar to other open ocean vertical profiles, except for the upper layers, where terrestrial influences were pronounced in this study. The major proportions of trace elements determined in this study were of the Chelex-labile fractions, indicating that they were reactive and bioavailable. There is a small part of inert fraction, and the proportions are different between inshore and offshore waters, with pronounced inert fractions in near-shore waters.
4

Living (Rose Bengal Stained) Benthic Foraminifera in Sediments off the Southwestern Taiwan and Dongsha Atoll

Lin, Juei-Chun 04 September 2011 (has links)
The subject of this study was to investigate the species composition and spatial distribution pastern of iving (Rose Bengal stained) benthic foraminifera in sediment surface samples (0-1 cm) off the Southwestern Taiwan and Dongsha Atoll. The main objectives of this study was to document the living benthic foraminiferal assemblages off the Southwestern Taiwan and Dongsha Atoll and to examine their distribution in relation to environmental parameters. Four benthic foraminiferal biofacies were recognized within the substrate type in Dongsha Atoll: A1 (Fine-grained) is represented by Pseudomassilina spp. - Quinqueloculina parkeri, A2 (Fine-grained) is represented by Hauerina spp. - Pseudomassilina spp., B1 (Coarse-grained) is characterised by Calcarina spp. - Quinqueloculina spp., B2 (Coarse-grained) is characterised by Amphistegina spp. - Quinqueloculina spp. Sediment surface samples off the Southwestern Taiwan during May 2009 led to the identification of four assemblages. Assemblage A is characterised by Ammonia spp. - Bolivina spp., Assemblage B between is characterized by Asterorotalia spp. - Globobulimina spp., Assemblage C is represented by Cibicides spp. - Nummulites spp., Assemblage D is represented by Ammonia spp. - Cibicides spp. Sediment surface samples off the Southwestern Taiwan during Nov. 2009 led to the identification of three assemblages. Assemblage A is dominated by Ammonia spp. - Cibicides spp., Assemblage B is characterised by Ammonia spp. - Bolivina spp., Assemblage C is characterised by Asterorotalia spp. - Bolivina spp. Stained benthic foraminifera form Dongsha Atoll correlated with current wave, collected site, coarse fraction and TOC contents. Living benthic foraminifera off the Southwestern Taiwan seems not to be related with TOC contents and coarse fraction, the assemblages were found to be more related to tidal energy and lateral transport.
5

Determination of Silver in Seawater Using An Organic Complexation-Acid Extraction Method

Chen, Wei-Han 11 September 2012 (has links)
Silver concentrations in natural water are very low and generally require preconcentration prior to instrumental analysis. Solvent extraction and anion exchange methods are the most commonly applied techniques for the determination of Ag in water samples. In this study, solvent extraction and anion exchange techniques are combined and modified to an ¡§organic complexation-acid extraction¡¨ method. The procedure developed involves four steps: (1) a buffer is added and the pH of the solution is adjusted for optimization purpose; (2) APDC and DDDC chelating agents were added and the silver in the solution is organically complexed; (3) the solution was passed through AG-MP1 anion exchange resins and silver complexes and their flocculant were retained and; and (4) acid solutions were used to extract silver from the column for subsequent determination of sliver by a graphite furnace atomic absorption spectrophotometer. After the experiments, the optimal procedures were established as the following: The pH of a 1-L aqueous sample was adjusted to ~4.5 by adding a buffer solution. Aliquots of 2.5-mL solutions containing chelating agents (2% w/v each of APDC and DDDC) were added. After being mixed, the solution was passed through an anion exchange column (AG MP-1) and silver complexes (and their flocculated particles) retained. Two 0.5¡VmL aliquots of 6, 4 and 2 N HNO3 were used to extract Ag from the column, aided by sonication for 3 min during each extraction procedure. The final volume is 3 ml, yielding a concentration factor of ~333. Determination of sliver was done by a graphite furnace atomic absorption spectrophotometer. The detection limit is 1.03 pM. This method was suitable for both freshwater and seawater samples, and was successfully applied for the determination of Ag in coastal and off-shore seawaters collected from coastal region off southwestern Taiwan.
6

Distribution, growth and reproduction of splendid ponyfish, Leiognathus splendens (Cuiver 1829) in the coastal waters off southwestern Taiwan

Chen, Pin-Hsuan 07 August 2005 (has links)
This study investigated the distribution, growth and reproduction of splendid ponyfish (Leiognathus splendens), the most dominant fish species in the catches of demersal trawls, along the coastal waters off southwestern Taiwan. Samples were collected once every 1-2 month (7-8 times per year), from January 2001 to January 2004 at seven stations, including Fangliao, Linbian, Dapeng Bay, Linyuan, Jhongjhou, Zuoying and Jiading, in southwestern Taiwan. The results showed that the distribution of L. splendens had significant differences among seasons, sites and water depths. The monthly mean abundance peaked in April, July and December, whereas lowest in January. L. splendens appeared in the north of Jhonhjhou only in the period from June to November. Based on their occurrence, the ponyfish could be separated into south and north groups at Linyuan. The south group can be further divided into inshore and offshore subgroups. The south group was more abundant than the north group. The size of L. splendens ranged from 15.32 mm to 121.01 mm (TL¡×total length), with an asymptotic length (L¡Û) of 128.20 mm and a catabolic growth coefficient (K) of 0.16(on a yearly basis). The ova diameter raged from 101.01 to 966.37 um with a peak between 500 and 600 um. The reproductive characteristic of L. splendens postulated as an asynchrouous spawner, who may spawn from March to May at Dapeng Bay and Linbian. The sex ratio (female/male) was less than 0.5 in total samples, and their first maturity length (L50) for female and male were 72.93 mm and 68.22 mm respectively. The distribution of L. splendens is associated with hydrology, season and ocean current. Higher abundance is normally coincided with low salinity, density, oxygen dissolution, and high water temperature and high value of Cpar (corrected irradiance-photosynthetically available radiation). The SCSW (South China Sea Water) and SCSSW(South China Sea Surface Water) with high temperature and low salinity flowing northward into the Taiwan Strait during the southwest monsoon season of May-September may deeply influence the northward distribution of the fish. Bigger fish and mature female capture during the spawning season from March to May, besides, smaller fish (TL¡Õ 20 mm) abundance on April, July and October. Additionally, the rainfall and nutrient wash away from onshore by typhoons, are the factors increase catches of L. splendens in the coastal waters of southwestern Taiwan.
7

Spatiotemporal Distribution and Reproduction of Callionymids along the Southwestern Coastal Waters off Taiwan

Pan, Yi-ting 30 June 2006 (has links)
This study aims to investigate the temporal-spatial distribution and reproduction of the Callionymidae, a dominant bottom-dwelling family at southwestern Taiwan. Samples were collected once every 1~2 month from January 2001 to January 2005 at seven stations, including Jiading, Zuoying, Jhongjhou, Linyuan, Dapeng Bay, Linbian and Fangliao, along the southwestern coast of Taiwan. A total of 5,846 samples was obtained, including 3 genera and 15 species. More species were found in this study than previous ones. The distribution of callionymids showed the significant variations in season, site and year. The highest abundance months occurred during March to October annually, with the most abundant at Jiading, then decreased in numbers southwards. Callionymus planus (52%)¡BCallionymus curvicornis (28%)¡BCallionymus virgis (7%) and Callionymus filamentosus (6%) were the top four dominant species. The four dominant species appeared abundantly around their spawning season. C. planus, C. curvicornis and C. filamentous were serial spawners, with peaking period at March-May, November-March and February-April, respectively. Both C. planus and C. curvicornis were most abundant at Jiading, and decreased southwardly, whereas the C. virgis and C. filamentosus were most abundant at Fangliao and Zuoying, respectively. All dominant species were revealed resource partitioning in relation to their reproductive activities. Callionymus planus that grew fast and recovered quickly among the callionymids, predominated in this area. Both C. planus and C. curvicornis showed significant reproductive isolation at the same area, both with a southward decrease in number. Calllionymus virgis separated from others and lived in the southmost site. Furthermore, C. filamentosus had a spawning period between C. planus and C. curvicornis.
8

Assemblages of epibenthic shrimps in coastal waters off Southwestern Taiwan

Chen, Hsu-sen 13 July 2006 (has links)
This study is aiming to investigate the distribution of epibenthic shrimp communities in relation to the environmental factors of their habitats in the coastal sandy bottom of southwestern Taiwan. Shrimp samples were collected from April 2002 to July 2003, with a beam trawl operated at seven stations along the coasts. Simultaneously, water temperature, salinity, dissolved oxygen were measured and sediments were collected. Particle size and organic matter of the sediments were then analyzed in the laboratory. The results of PCA analyses on these environmental factors revealed that the observations could be segregated into two groups along the PC1, representing rainy season with high temperature, low salinity and dry season with low temperature, high salinity, respectively. The observations with coarse particle (>0.125 mm), representing samples from north sites, were found to distribute in the upper part of the PC2; while those with fine particle (<0.125 mm), representing samples from south sites, distributed in the lower part. In total, 15,591 individuals of shrimp were collected, including 20 genus, 39 species. Metapenaeopsis palmensis (88.2%), Trachysalambria curvirostris (3.6%), M. barbata (3.5%) and Parapenaeopsis cornuta (1.4%) were the four dominant species. Significant differences in the spatial distribution were due to the different composition of the dominant species. Although M. palmensis was the most abundant species in most stations, its percentage abundance was the lowest at Fangliao and Jiading, where the dominant species were T. curvirostris for the former and M. barbata and P. cornuta for the latter. Species preferences for various combinations of environmental variables are responsible for shifts in the structure and overall abundance of assemblages and dictated some patterns. Higher abundances of T. curvirostris, Trachypenaeus granulosus, and Solenocera koelbeli were associated with the appearance of high temperature, low salinity and very fine sand, representing the environmental features of Fangliao and Linbian during the rainy season. Stenopus hispidus, Metapenaeus moyebi, Metapenaeus ensis and M. palmensis were abundant coinciding with low temperature, high salinity and high silt and clay that reflecting the dry season of Linyuan and Linbian waters. Metapenaeopsis dalei and M. barbata appeared in large numbers at habitats with high temperature, low salinity and coarse sand, which mainly occurred in Zouying to Jhongjhou during the rainy season. Moreover, Scyllarus rugosus and Parapenaeopsis cornuta seemed to prefer coarse sandy bottom mainly distributed from Jiading to Linyuan. Temporal fluctuations were associated with the population dynamic of the dominant species. The abundance was reduced while the M. palmensis migrated to open sea in late summer and early autumn. As the juveniles of M. palmensis and M. barbata back to the inshore waters, the abundance were increased and reached the peak in spring. Because of the limited distribution, T. curvirostris and P. cornuta were not influence the overall temporal fluctuations but the local fluctuations. Overall, temporal fluctuations act more at a specific level even structural one, and may be linked to some particular stages of the benthic shrimp life cycle, but do not significantly influence the spatial organization.
9

Tempospatial distribution of platycephalids and the biology of Suggrundus macracanthus in the waters off southwestern Taiwan

Huang, Chien-Chih 11 September 2007 (has links)
This study aims to describe the spatial and temporal distribution of Platycephalids and the biology of the dominant species Suggrundus macracanthus, in the coastal waters off southwestern Taiwan. A beam trawl was adopted to collect fish samples from 7 stations, including Jiading, Zouying, Jhongjhou, Linyuan, Dapeng Bay, Linbian and Fangliao. Samplings were carried out on a 1-2 month interval, started from June 2000 and ended in August 2005. In total, 3,780 specimens were collected, including 9 genus 11 species. The distribution of Platycephalids varied in station, water depth and season. The lowest abundance were recorded at Jiading, then decreased from Zouying to Linyuan, and then increased southwards. Platycephalids eived more abundant in depth 25-55 m, and the number increased with depth 15-35 m. The highest abundance occurred from spring to summer. S. macracanthus (74%) were the top dominant species. S. macracanthus spawn once a year during February to April, with a peak in the frequency distribution of egg diameter. The recruitment of S. macracanthus occurred in the period from June to July, at near-shore waters of 15 m depth with mud and sand substrata. S. macracanthus take epibenthic shrimp as the major diet accounts for above 68%, including 59% of Metapenaeopsis palmensis. Other food items still had the fish, crab, Mollusca and Amphipoda. S. macracanthus juveniles nearly didn¡¦t ate crab, but the adult ate crab up to 12%.

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