Abstract This research was conducted to understand whether phosphorus limits the phytoplankton production in the South China Sea (SCS). In the nutrient enrichment experiments nitrate and phosphate were supplemented to surface sea water and the enhancement of chlorophyll a concentration during incubation was observed. Seasonal field survey was conducted to measure ambient abundance of phosphorus including phosphate (SRP) and dissolve organic phosphorus (DOP), as well as alkaline phosphatase activity (APA) in the nautral sea water in the contiential shelf and basin of the SCS. Except at the contiential shelf in summer and the mouth of Zhu Jiang River in fall, the nutrient concentration of surface water was low in the SCS. The average¡£NO3+NO2¡¤was 20 nM (fall) - 360 nM (winter ). The average SRP concentration was 16 nM (fall) - 87 nM (winter). The average DOP concentration was 0.08 £gM (summer)- 0.25 £gM (winter). The ¡£NO3+NO2¡¤/ SRP ratio was smaller than the Redfield N/P ratio of 16. The average chlorophyll a concentration (Chl a) was 0.13 £gg l-1 (summer) - 0.48 £gg l-1 (winter). The average concentration of the particlulate organic carbon (POC) was 4.58 £gM (spring) - 8.11 £gM (winter). The average APA was 16 n mol l-1 h-1 (fall) - 87 n mol l-1h-1 (winter). The average of APA/Chl a was 33.94 n mol £gg -1 h-1 (winter) - 97.22 n mol £gg -1 h-1 (spring). The results of the enrichment experiment show that the phosphorus deficiency was observed on the contiential shelf in the summer of 2001 and at the mouth of Zhu Jiang in the fall of 2002. The common characteristics of the phosphorus deficient regions were low salinity (29.90- 30.87 psu ), high¡£NO3+NO2¡¤(1.31 - 3.01 £gM) , and a ¡£NO3+NO2¡¤/ SRP ratio higher than 16. Chl a increased significantly (p<0.05) by the enrichments of phosphorus. In spring and winter when all regions were N-limited, N enrichment significantly (p<0.05) increased Chl a. In fall, all the contiential shelf region except the mouth of Zhu Jiang River, the slope and basin regions were NP co-limited. The Bashi Strait in summer was also NP co-limited. P-limitation that was seen in the contiential shelf SCS and at Zhu Jiang River mouth, was probably caused by the influence of river discharge. N/P, SRP or APA were not effective parameters to assess whether marine phytoplankton growth was limited phosphorus, nitrogen or both. In the SCS, the P-limited water masses were, in general, low in salinity, high in¡£NO3+NO2¡¤,Chl a,¡£NO3+NO2¡¤ / Chl a, APA and a N/P ratio higher than 16. The water masses that were N-limited was high in salinity, and low in¡£NO3+NO2¡¤, Chl a,¡£NO3+NO2¡¤/ Chl a and APA, as well as a N/P ratio smaller than 16. The water masses that were nitrogen and phosphorus co-limited were different from the N-limited ones in that they were low in SRP, SRP/Chl a, and DOP. The SRP and DOP concentration in the NP co-limited region were 11 - 28 nM and 0.09 - 0.23

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.

In the design and plan of the coast engineering, long-term and continual tidal database represent the indispensable role. This paper collect the tidal database, their locations include the ocean around the Taiwan and the South China Sea. Use the artificial neural networks (ANN) to build model and find the relationship between neighbor tidal observation stations. There are many reasons to cause the tide phenomenon, include the tide generating force, season, coastal geography, geography of sea floor, resonance of gulf or estuary, change depth of sea, and so on, it will be determined by local environment. The tide analysis and prediction usually use the harmonic analysis method. This method need long-term and continual tidal record, and the theory depend on the tide generating force, it has limit about accuracy. The application of artificial neural networks is used in nonlinear science problems in general cases. The back propagation (BP) networks is the one model of the artificial neural networks, this paper use ANN-BP model to build the relationship from different tide observed stations, and verify the quality of model. From the result of verified models, the ANN-BP model can predict and supplement the tide record very well. The items of research include: ¡i1¡j the relationship between two neighbor tide observed stations. (one station input, one station output) ¡i2¡jthe relationship between three neighbor tide observed stations. (two station input, one station output) ¡i3¡j input several tide observed stations and output one station. ¡i4¡j the correlation of connected weight and threshold between different models. ¡i5¡j change the parameters of ANN-BP model and discus the affect of model¡¦s quality. ¡i6¡j application of truly case. From the result of this paper, in the design and plan of the coast engineering, the long-term tide observed record can be predict from the ANN-BP model and tide record of neighbor observed stations. When the tide record has miss or lost cause by machine or other reasons, the ANN-BP model can supplement the lost tide record well. This paper show the ANN-BP model can be apply to predict and supplement the tide record very well, and will be possible applied method.

This study utilized, for the first time, the d18Osw as a tracer to investigate the seasonal variations of circulation in the Taiwan Strait (TS), which is the predominant sea passage with an average depth of 60 m connecting the East China Sea (ECS) and the South China Sea (SCS). The result shows that the circulation system in TS is mainly influenced by the inter-mixing among the China Coastal Water (CCW), the SCS water (SCSW), and the Kuroshio Water (KW). In spring, the KW dominates in TS, whereas the CCW is still observed in northwest TS. During the summer, SCSW replaces the KW and becomes the major water type in the TS, yet the KW is found to be restricted in the southwest part and the bottom of the TS. Due to the larger discharge from rivers (mainly the Yangtz River), the CCW has a more extensive distribution in the TS in summer than other seasons. In fall and winter, the CCW occupies the northern part of TS due to the stronger northeastern monsoon which limits the intrusion of the KW through the Luzon Strait to the northern TS. The two distinct water types inevitably form a front in the central TS. The hydrographic variations at Penghu Channel (PHC) were also explored in this study. The d18Osw indicates that the perennial intrusion of the KW into the PHC is varying throughout different seasons. This intrusion is found strongest in fall and winter. In summer, the upper layer of PHC is occupied chiefly by SCSW, while the KW remains at the bottom layer in PHC. By including an additional inflow of 0.5Sv from TS to ECS, this study further reconstructed a box model of the ECS, which was previously furnished by Lin(1999). The new estimates suggest that ~0.38*104 km3/year of the Kuroshio surface water (0-50m) and ~1.54*104 km3/year of the upwelled Kuroshio subsurface water (50-150m) are transported to the ECS, while ~3.83*104 km3/year of the ECS water are exported to the western Pacific Ocean.

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.

El Ni&#x00F1;o is now a focal point for global climate change research, but its influence on the Western Pacific is still uncertain. Taiwan Strait is an important pathway, which connects the South China Sea and the East China Sea, and is strongly influenced by the monsoon. Generally, in winter, the strong winter monsoon brings the cold and nutrient-rich Changjiang Diluted Water¡]CDW¡^southward. While during the El Ni&#x00F1;o event, because of the weakened south wind in northern Taiwan, more cold CDW moves southward, and hence the decreased seawater temperature in spring and fall. The trend is opposite in summer. There is a high salinity signal in the seas outside of Hsin-Chu, suggesting sea water coming from the Kuroshio, which has circumvented the northeast tip of Taiwan. Meanwhile, there is a front which separates this Kuroshio water and CDW. During the El Ni&#x00F1;o, the front moves eastward, especially in summer. The salinity east of the front decreases gradually from spring to winter water, the center of upwelling located at the eastern side of the front in spring, and at or near the front from summer to winter. Furthermore, The N/P ratio of the northern Taiwan Strait water became higher after the Three Gorges Dam (TGD) became operational. The nitrous oxide (N2O) is a long-lived greenhouse gas. Unfortunately, in Taiwan, there are few data about N2O emission from rivers, lakes and coastal areas. This research also studies the N2O distribution in natural waters around Taiwan. The average surface water concentration and sea to air flux in the Taiwan Strait¡]7.81¡Ó1.28nM¡F0.28¡Ó0.38£gmol/m2/hr¡^is higher than in the South China Sea¡]SCS¡F7.55¡Ó2.45 nM¡F0.21¡Ó0.27£gmol/m2/hr¡^and the West Philippine Sea¡]WPS¡F5.3¡Ó0.62nM¡F-0.20¡Ó0.25£gmol/m2/hr¡^, which displays a rare sink signal in the world oceans. There is an N2O maximum observed around 1000m in the WPS, and another shollower one around 700m in the SCS, presumably because of the intenive upwelling and vertical mixing in the SCS basin. There are some rather high N2O concentrations (N2O>30nM) in the SCS, observed near the continental slope. We assume that these are released from sediments on the continental slope. Although the sea-to-air flux of N2O is much lower than the flux of CO2, N2O emission in the SCS contributes more than two times the greenhouse effect than CO2 does. Besides, The N2O concentration during El Ni&#x00F1;o is lower than usual, probably due to a smaller amount of the CDW. Finally, the average N2O concentrations of river and submarine groundwater discharge in Taiwan are about 32.3¡Ó43.3nM and 9.72¡Ó13.2 nM, respectively.

Except for direct drilling and sampling of marine gas hydrates, the occurrence of gas hydrates has been identified generally by inference from indirect evidence, derived from geological, geophysical, and geochemical data. In this paper, we intend to discuss the geochemical anomalies of pore waters and their implications for gas hydrate occurrence in the northern continental slope of the South China Sea. The molecular concentration and isotopic composition of methane in sediments can provide clues to gas sources, whereas ionic and isotopic compositions of pore waters, such as steep SO42- gradients, shallow SMI (sulfate-methane interface) depths; decreasing pore water chlorinity, and heavy oxygen isotopic compositions, are used to identify gas hydrate occurrence and the distribution and thickness of sediment layers containing gas hydrates. Other good geochemical indicators include anions and cations concentrations such as Br-, I-, PO43-, NH4+, Ca2+, Mg2+, Sr2+, B3+, Li+, and Ba2+ in pore waters. We also found that the very negative carbon isotopic compositions of dissolve inorganic carbon (DIC) in pore waters can serve as good indicators for gas hydrate occurrence. In the South China Sea, three most promising target areas for gas hydrates include the Dongsha, Shenhu, and Xisha Trough.

In April-June of 2007, a gas hydrate drilling expedition was carried out by using M/V Bavenit in Shenhu Area, the north slope of South China Sea. High concentrations of hydrate (>40%) were obtained in a disseminated forms in foram-rich clay sediments at 3 selected sites. The hydrate-bearing sediments ranged several ten meters in thickness are located in the lower part of GHSZ, just above the BGHSZ, and are typically characteristic of higher sonic velocity and resistivity, and lower gamma density in wireline logging profiles. Evidences for gas hydrate include the IR cold spots and temperature anomalies, salinity and chlorite geochemical anomaly of pore water for non-pressurized cores, and X-ray imaging, high p-wave velocity and low gamma density, and high concentration of methane from the pressurized cores. Gasses are mainly methane (max. ethane 0.2-0.3%), therefore only hydrate S1 is formed. It is inferred that the foram content and other silt size grains may provide enough free water for the hydrate to happily occupy both the large spaces in the forams and for it to distribute itself evenly (disseminated) throughout the formation. It is possible that all the forams are hydrate filled. As the forams are visible does this not count for visible white gas hydrates.

南海是太平洋與印度洋間的重要國際海運航道，因為具有重大的地緣戰略利益，對亞太安全有重大的影響，因此涉入南海爭端的國家眾多。在南海主權的各聲索國中，越南宣稱擁有西沙群島與南沙群島的全部主權，是中國大陸南海爭端中的最大競爭對手；南沙群島周圍近越南、菲律賓、馬來西亞、印尼的海域已有相當量油產，全球貿易有25%經過南海，其中臺灣、日本及南韓的石油輸出線均依賴此航道，漁場亦為周邊國家最重要的漁獲來源，是西太平洋中最具戰略和經濟價值的群島，也是目前國際糾紛最多之處；2010年越南利用擔任東協輪值主席國的機會，刻意引進美、日等區域外勢力，將南海問題導向國際化與東協化，以構建與各大國間的等距平衡交往戰略，藉以抗衡中國大陸，並從中獲得外交自主性。目前中國大陸對南海問題係採取「主權歸我、擱置爭議、共同開發」的政策，但仍積極強化南海戰力與維權執法作為，並堅持「反對區域外國家參與」及「雙方協商」的原則，以獲得最大的優勢。中越南海爭端涉及國際衝突管理與權力平衡，臺灣為南海主權聲索國之一，占有南沙群島的最大島嶼－太平島已60餘年，在面對中國大陸與越南等國積極強化南海經營管理策略及戰略部署的同時，我國更應思考如何強化南海主權作為，積極參與南海競局，以確保國家最大利益

Nos últimos anos, as disputas territoriais no Mar do Sul da China (MSCh) têm ganhado cada vez mais atenção dos estudiosos de Relações Internacionais, por envolver uma região que tem sido classificada como o mais recente centro dinâmico internacional. A questão do MSCh envolve desde potências mundiais como China, e marginalmente os Estados Unidos, até potências regionais, como Vietnã, Filipinas e Malásia. Muitas análises, entretanto, têm indicado cenários que parecem não condizer com a realidade ou com a evolução dos acontecimentos no MSCh: isso porque muitas delas desconsideram elementos históricos, políticos e culturais típicos da região asiática em sua interpretação. Entender o MSCh envolve também entender a própria percepção Asiática sobre as Relações Internacionais, em específico no Sudeste Asiático, buscando identificar os fatores que determinam e influenciam o modus operandi regional. O objetivo desta dissertação é, portanto, analisar a questão do MSCh a partir de uma perspectiva asiática, aqui representada pela China e pelo Vietnã. Este enfoque é o fio condutor da dissertação que apresenta os diversos elementos relacionados à questão do MSCh, buscando entender como a visão dos atores envolvidos é capaz de nos colocar uma nova forma de interpretar o objeto de estudo. No último capítulo, apresentam-se autores que mobilizam conceitos tipicamente asiáticos, como hierarquia e harmonia, para analisar as relações internacionais asiáticas. Na conclusão, expõe-se como a perspectiva asiática de análise, que mobiliza elementos históricos, culturais e políticos locais para a interpretação das relações regionais, oferece uma contribuição mais adequada à compreensão da questão do Mar do Sul da China. / In the last few years, the territorial disputes at the South China Sea (SCS) have attracted more attention from International Relations experts, since it involves the region considered as the new world’s dynamic center. The issue of the SCS involves world powers, such as China and, on a smaller scale, the United States, and regional powers, such as Vietnam, Philippines and Malaysia. However, many studies have created scenarios that do not match with reality or with the conduct of events: this happens because many of them do not take into account historical, political and cultural aspects typical from the Asian region. In order to understand the SCS it is important to comprehend the Asian perception of International Relations, especially at Southeast Asia, identifying historical, political and cultural traits that support the regional modus operandi. Therefore, the aim of this essay is to analyze the SCS issue from an Asian perspective, here represented by China and Vietnam. This approach is the thread of the dissertation, which presents the different elements involving the SCS in an effort to understand how the Asian vision of the matter can present us with new ways of interpreting the object under study. In the last chapter, we mention authors who articulate some tipically Asian concepts, such as hierarchy and harmony, to study the Asian international relations. The conclusion brings the argument that the Asian perspective, while using historical, cultural and political elements whose origins come from Asian history, offers a more adequate contribution to comprehend the South China Sea issue.