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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.
21

An overview on the variation of sea surface pCO₂ in Northern South China Sea and its management

Lau, Pik-ha, 劉碧霞 January 2013 (has links)
To have better understandings of the partial pressure of carbon dioxide (pCO2)in northern South China Sea(NSCS), the pCO2readings from 1999-2012 were reviewed. Both the pCO2in NSCS and in the atmosphere also showed an increasing trends and the pCO2in NSCS varied across the seasons. There are many important processes that influenced the pCO2in NSCS, which were the rise of the temperature, biological production, seasonal upwelling, Pearl River discharge, increase in the concentration of atmospheric pCO2and the rate of calcification. These six mechanisms extend different strengths on the resultant sea surface pCO2in NSCS. The impact of induced sea water acidification on the marine phytoplankton by the high pCO2in NSCS would also be discussed. The drop of pH in the seawater would change the community of phytoplankton from diatom to dinoflagellate as a resistance to the change of pH of dinoflagellate that was better than the diatom. DMS, which was one of the climatically important gases, would also affected by the high pCO2induced seawater acidification. Hong Kong (HK) was studied as a case to estimate whether NSCS also faced the same impacts upon by the marine phytoplankton. The study showed that the diatom was relatively sensitive to the drop of pH in HK waters. The DMS producing marine phytoplankton was also affected by the drop of pH in HK waters. It was concluded that the NSCS might also face the same situation with HK. Finally, three instruments were recommended to have a better management in NSCS, namely, knowledge gaps and NSCS research priorities, valuing the NSCS as well as decision making team. Firstly, filling the knowledge gaps and NSCS research priorities aim to enhance the ability of the ocean sequestration to absorb and store the largest amount of anthropogenic CO2as possible. Afterwards, valuing the NSCS aims to protect the marine organisms, such as the phytoplankton, form the negative impacts of the decrease of ocean acidity. Last but not least, a good decision making team aims to balance the conflicts between those various options to reduce the anthropogenic CO2with ocean sequestration and impacts result from the ocean sequestration. / published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
22

Understanding the Dynamics of Misperceptions in Southeast Asia

Lin, Tsu-Yuan 01 January 2015 (has links)
This thesis seeks to understand the current dynamics of misperceptions in Southeast Asia. The paper would focus on three actors in the region: China, the U.S., and a representative state of ASEAN, Vietnam. The actors would be examined in the context of the South China Sea disputes. The essential goal of U.S. policymakers it to achieve peace and stability in the region by building a liberal order, but the existence of misperceptions makes it highly challenging. The misperceptions stem from the fact that each actor has to predict what paradigm what other actors’ actions are based on in the region. In order to reduce misperception, there must be a high level of trust derived from consistent rhetoric accompanied with actions. The paper finds that the problem lies in the fact that to achieve a coherent foreign policy that other actors can interpret consistently, there must be a convergence of domestic politics and other states’ actions that allows each actor to have a positive and constructive interpretation of its options. The paper examines how domestic politics can often hinder a coherent foreign policy that eliminates confusion for other actors. Furthermore, in the case study between the three actors, China, the U.S., and Vietnam, will demonstrate how actors’ behaviors and actions can be changing due to other actors and domestic politics. Therefore, the paper suggests several policies that the U.S. needs to take in order to reduce the tension between domestic politics and other states’ actions.
23

The gravity field of Sundaland : acquisition, assessment and interpretation

Holt, Robert Andrew January 1998 (has links)
The 1995 Sandwell & Smith WGI7.2 satellite gravity map has been compared with high quality ship gravity data offshore Sabah. The standard deviation of the differences between gravity profiles interpolated from WGI7.2 and the ship survey was 5.7 mGal. Spectral analysis indicated that WGI7.2 resolves features with half-wavelengths greater than 10 km. Three hundred new gravity stations, including ten base stations tied to IGSN71, were established during a survey of Sabah and were merged with two previous surveys to complete the gravity coverage of the state at reconnaissance level. New gravity maps of Sundaland, compiled from the Sabah and WGI7.2 gravity data sets have been interpreted. ' Subtraction from these data sets of the long wavelength GEM-T3 gravity anomaly field, which is dominated by the effects of the subducted proto-South China Sea and the ongoing subduction of the Australian, Indian and Philippine Sea Plates, achieved a simple 'regional-residual' separation and the isolation of crustal-scale anomalies. 5' x 5' maps of the depth to Moho, crustal thickness and β (crustal extension) factor beneath the Sunda Shelf and the South China Sea have been produced by 1-D geometric manipulation of the marine gravity field using sediment isopach and bathymetry control data. The average difference between the new Moho map and seismic refraction depth-to-Moho estimates at the south China margin was 0.2 ± 2.0 km. The Moho rises from an average depth of 29 km beneath the Sunda Shelf to a depth of about 16 km beneath the South China Sea oceanic basin. It is estimated that approximately 1100 km of oceanic crust of the proto-South China Sea was subducted at the northwest Borneo margin. Gravity modelling independently confirmed the average 35 mm/yr spreading rate prediction for the southwestern subbasin of the South China Sea oceanic basin from magnetic lineation interpretation. Quantitative interpretation indicates that Sabah is underlain by thick continental crust, and gravity modelling of the Maliau Basin predicts a minimum sediment thickness of 8 km. The ophiolite bodies at Telupid and Darvel Bay are separated by a gravity low and there is no evidence that the two are related. The crustal root of the Crocker Ranges extends to a depth of ~49 km below sea level. In order to reach this present day crustal thickness, the turbiditic sediments forming the Crocker Ranges must have been compressed to less than half of their original lateral extent during the Sabah Orogeny.
24

Estimation of geoacoustic properties in the South China Sea shelf using a towed source and vertical line hydrophone array /

Marburger, John M. January 2004 (has links) (PDF)
Thesis (M.S. in Physical Oceanography and Meteorology)--Naval Postgraduate School, Dec. 2004. / Thesis Advisor(s): Ching-Sang Chiu. Includes bibliographical references (p. 33). Also available online.
25

Law and politics in the South China Sea assessing the role of UNCLOS in ocean dispute settlement /

Hong, Nong. January 1900 (has links)
Thesis (Ph.D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on April 27, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Dept. of Political Science, University of Alberta. "Spring 2010." Includes bibliographical references.
26

Law and politics in the South China Sea assessing the role of UNCLOS in ocean dispute settlement /

Hong, Nong. January 1900 (has links)
Thesis (Ph.D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on April 27, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy, Dept. of Political Science, University of Alberta. "Spring 2010." Includes bibliographical references.
27

「南シナ海問題」の形成 : その変容と要因 / ミナミシナカイ モンダイ ノ ケイセイ : ソノ ヘンヨウ ト ヨウイン / 南シナ海問題の形成 : その変容と要因

黒杭 良美, Yoshimi Kurokui 20 March 2019 (has links)
博士(政治学) / Doctor of Political Science / 同志社大学 / Doshisha University
28

Molecular ecology of ammonia oxidizing archaea and bacteria

Cao, Huiluo., 曹慧荦. January 2011 (has links)
The newly recognized ammonia-oxidizing archaea (AOA) makes re-evaluation of the contribution to ammonia oxidization by both AOA and ammonia-oxidizing bacteria (AOB) necessary and meaningful. The growing population and increasing anthropogenic activities around coastlines have affected wetland and coastal marine ecosystems through discharging polluted water containing large amounts of reactive inorganic nitrogen. The objectives of this study were to detect the phylogenetic diversity and abundance of ammonia oxidizers including AOA and AOB on different scales and to elucidate the distribution patterns along an anthropogenic pollution gradient from the coastal wetland of the Mai Po Nature Reserve in Hong Kong to the South China Sea (SCS). Generally, besides lineages shared by similar environments, various endemic lineages were also observed in the polluted mangrove sediments of Hong Kong, and in the coastal, and deep-sea surface and subsurface sediments from the SCS indicating their geographical distance should be responsible for these phylogenetic distinctions. The community structures of AOA and AOB observed were proposed to be associated with environmental parameters including metals and total phosphorus (TP) separately in the sediments while their abundance was correlated with the pH value and temperature. On the other hand, along a profile of surface sediments with stable salinity from the coastal margin to the slope in the SCS, a clear community structure transition was detected for both AOA and AOB, showing major differences in each of their responses. Although the abundance of AOA was lower than that of AOB in the subsurface sediment samples from the SCS, the statistical support for relationships between AOA and nitrite concentration shed new light on the active contributor to the subsurface nitrogen cycle in the oxygen minimum zone from the deep-sea sediments. On a large scale, along the anthropogenic pollution gradient from the Pearl River Delta to the coastal margin and then the SCS, the dominant genus transition from Nitrosomonas to Nitrosospira was detected in response to the salinity and anthropogenic influences. Among a wide spectrum of environmental conditions in the western Pacific, a suite of statistical analyses clearly delineated the shallow and deep-sea sediments clusters suggesting that the depth and other contributing environmental factors involved shape the current distribution pattern of AOA. On a global scale, our understanding about the systematics and evolution of AOA was advanced through phylogenetic analyses. Salinity, lifestyle and temperature were proposed to be responsible for the global distribution patterns of AOA. On the basis of studies in the anthropogenic influence areas, the methods to detect specific responses of ammonia oxidizers to known anthropogenic pollution were concluded. Highlights of this study advance not only our understandings about phylogenetic diversity of ammonia oxidizers and the driving forces shaping their community structure and distribution patterns, but also a revised comprehensive view about them on the larger scale. / published_or_final_version / Biological Sciences / Doctoral / Doctor of Philosophy
29

Investigation of baroclinic tides in the northern South China Sea

Guo, Chuncheng January 2013 (has links)
Baroclinic tides result from the interaction of barotropic tides with topography in stratified oceans. They play an important role in driving deep ocean mixing. In this research, investigations of the dynamics of baroclinic tides and internal solitary waves (ISWs) in the northern South China Sea (SCS) are conducted, mainly by means of the Massachusetts Institute of Technology general circulation model (MITgcm). Firstly, simulations of internal wave generation at the Luzon Strait (LS) are carried out. By conducting three-dimensional (3D), high-resolution experiments, it was found that the generated wave field features a multi-modal structure: large, pronounced ISWs of first mode (amplitude ~120 m) and second mode (amplitude ~120 m) were reproduced. The two north-south aligned ridges in the LS contribute together to the generation of the second mode ISWs, whereas the easternmost ridge of the two is responsible for the first mode ISWs. It was found that multiple generation mechanisms of internal waves could occur in this region, and overall it belongs to a mixed lee wave regime. A specific type of short internal waves arose during the 3D simulation. These ride on a second mode ISW with similar phase speed, trailing a first mode ISW. The short waves possess wavelengths of ~1.5 km and amplitudes of ~20 m, and only show up in the upper layer up to a depth of ~500 m. Scrutiny of the generation process showed that these short waves appear in two distinct regions and are produced due to two mechanisms, namely, the disintegration of an inclined baroclinic bore near the LS, and the overtaking of a second mode ISW in the deep water by a faster first mode ISW. Robust evidence has been sought from satellite imagery and by solving the theoretical Taylor-Goldstein Equation to verify their existence. The effects of superposition of multiple tidal harmonics (diurnal and semidiurnal) on the resultant ISW generation were investigated. It was first found that, by analyzing historical observational data, the occurrence of ISWs in the far-field always follow strong semidiurnal barotropic tidal peaks in the LS, regardless of whether it is the maximum for the diurnal or total tidal strength. However, modelling results of MITgcm and a linear internal tide generation model demonstrate that the diurnal tidal harmonics modulate the arrival time and amplitude of the propagating ISWs. Specifically, it leads to the emergence of the so-called A and B type ISWs and an alternation and transition between the two. Secondly, the shoaling process of ISWs in the northern SCS slope-shelf area is investigated. A series of two-dimensional (2D) experiments are set up to study the shoaling of a large-amplitude second mode concave ISW over a linear slope that resembles the SCS slope. Modelling results show that a strong transformation of the wave profile starts to take place when the wave is approaching the shelf break. A convex type wave is born at the trailing edge of the incident wave and gradually disintegrates into a group of ISWs due to the steepening of the rear wave profile. The frontal face of the wave gets flatter when travelling on the slope, but forms a steep structure right above the shelf break. However, this steep structure shows no tendency to evolve into an ISW: instead, it gets increasingly flat again while evolving on the shelf. The trailing convex wave packet travels faster and merges with the frontal concave wave. Finally, a wave packet with rank-ordered convex ISWs moves forward steadily on the shelf. Energy transfer to the ambient modes is evident, as both first mode and higher modes are clearly seen during and after the shoaling process. First mode ISW evolution is studied too by performing 3D, high-resolution experiments over the wide northern SCS slope and shelf area. It was found that the wave profiles change drastically near the shelf break and the Dongsha Atoll. In agreement with satellite imagery, the wavefront of the leading ISW becomes more spatially oblique with respect to its original orientation as it progresses westward due to the inclination of the slope in the topography. Wave disintegration is prominent in the shallow water zone, and wave polarity reverses near the turning point (at the 130 m isobath), which is consistent with the predictions of weakly nonlinear theory. A series of 2D experiments were set up to inspect the effects of rotation on the shoaling ISW. The results indicate that under the rotation, upon reaching the continental shelf, one shoaling ISW could disintegrate into one ISW packet and one secondary solibore that contains a number of rank-ordered waves with much shorter wavelength than an ISW. The secondary solibore is very pronounced in the northern portion of the northern SCS slope and shelf, but could hardly be discerned in the southern portion, which is consistent with the outcome of 3D simulations.
30

Ecology of Calanus sinicus (copepoda, calanoida) in oceans of Southern China.

January 2003 (has links)
by Lee Ka Lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 153-167). / Abstracts in English and Chinese. / Abstract (in English) --- p.i / Abstract (in Chinese) --- p.iv / Acknowledgements --- p.vi / List of Figures --- p.vii / List of Tables --- p.xv / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter Chapter 2 --- "Seasonal population structure, life cycle and body allometry of the planktonic copepod Calanus sinicus" / Chapter 2.1 --- Literature Review / Chapter 2.1.1 --- Taxonomy of Calanidae --- p.6 / Chapter 2.1.2 --- Geographical and seasonal distribution of Calanus sinicus --- p.7 / Chapter 2.1.3 --- Body length and body weight of Calanus sinicus --- p.11 / Chapter 2.2 --- Introduction --- p.14 / Chapter 2.3 --- Materials and Methods --- p.17 / Chapter 2.3.1 --- Field sampling --- p.17 / Chapter 2 3.2 --- Identification and enumeration of zooplankton --- p.19 / Chapter 3 3.2 --- Body length and weight of Calanus sinicus --- p.19 / Chapter 2.4 --- Results --- p.20 / Chapter 2.4.1 --- Temperature --- p.20 / Chapter 2.4.2 --- Salinity --- p.21 / Chapter 2.4.3 --- Ambient Chlorophyll a concentration --- p.22 / Chapter 2.4.4 --- Seasonal occurrence and distribution of Calanus sinicus in northern Taiwan --- p.23 / Chapter 2.4.5 --- Seasonal occurrence and distribution of Calanus sinicus in Hong Kong --- p.26 / Chapter 2.4.6 --- Life cycle of Calanus sinicus in northern Taiwan --- p.27 / Chapter 2.4.7 --- Life cycle of Calanus sinicus in Hong Kong --- p.28 / Chapter 2.4.8 --- Stage ratio index --- p.28 / Chapter 2.4.9 --- Seasonal changes in biomass of Calanus sinicus --- p.29 / Chapter 2.4.10 --- Seasonal changes in the abundances of other copepods in northern Taiwan --- p.29 / Chapter 2.4.11 --- Seasonal changes in the abundances of other copepods in Hong Kong --- p.30 / Chapter 2.4.12 --- Seasonal changes in biomass of other copepods --- p.31 / Chapter 2.4.13 --- Seasonal variations in body size --- p.31 / Chapter 2.4.14 --- Seasonal changes in sex composition in adults --- p.32 / Chapter 2.5 --- Discussions --- p.32 / Chapter Chapter 3 --- Diel vertical migration and gut pigment rhythm of the planktonic copepod Calanus sinicus / Chapter 3.1 --- Literature review --- p.87 / Chapter 3.1.1 --- Diel vertical migration of Calanus sinicus --- p.87 / Chapter 3.1.2 --- Diel feeding rhythm of Calanus sinicus --- p.91 / Chapter 3.1.3 --- Measurement of grazing rate --- p.93 / Chapter 3.2 --- Introduction --- p.96 / Chapter 3.3 --- Materials and Methods --- p.98 / Chapter 3.3.1 --- Zooplankton sampling and physical parameters --- p.98 / Chapter 3.3.2 --- Identification and enumeration --- p.100 / Chapter 3.3.3 --- Gut pigment fluorescence --- p.100 / Chapter 3.4 --- Results --- p.101 / Chapter 3.4.1 --- Temperature and salinity --- p.101 / Chapter 3.4.2 --- Ambient chlorophyll a concentration --- p.102 / Chapter 3.4.3 --- Diel vertical migration --- p.103 / Chapter 3.4.4 --- Gut pigment content --- p.106 / Chapter 3.5 --- Discussion --- p.107 / Chapter Chapter 4 --- Use of molecular markers in population analysis of Calanus sinicus / Chapter 4.1 --- Literature Review --- p.134 / Chapter 4.2 --- Introduction --- p.138 / Chapter 4.3 --- Materials and Methods --- p.142 / Chapter 4.3.1 --- "Collection, preservation, and identification of Calansn sinicus samples" --- p.142 / Chapter 4.3.2 --- DNA sequence determination for Calanus sinicus --- p.143 / Chapter 4.4 --- Results --- p.144 / Chapter 4.5 --- Discussion --- p.145 / Chapter Chapter 5 --- Conclusion --- p.150

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