Methane (CH4) is not only important but also a long-lived greenhouse gas. Scientists estimated that more than half of CH4 is released from the water column. Studies of methane from water column are almost focused on rice fields, wetlands and swamps in Taiwan. There are only limited studies of methane about rivers, lakes and coasts. So this study investigated CH4 distribution in natural waters on and around Taiwan. The average surface methane concentration in the South China Sea (SCS) is about 5.10¡Ó3.61 nM (n=103). The average surface methane concentration in the West Philippines Sea (WPS) is about 3.44¡Ó3.89 nM (n=56), lower than in the SCS. The average surface concentration in the Northern and Southern Taiwan Strait are, respectively, 4.72¡Ó3.19 nM (n=64) and 4.01¡Ó3.19 nM (n=51), and are between the average concentrations in the SCS and the WPS. The sea-to-air fluxes of methane in the SCS and the WPS are 0.38¡Ó0.99 £gmol/m2/h (n=103) and £gmol/m2/h (n=56), respectively. The sea-to-air fluxes of methane in the Northern and Southern Taiwan Strait are, respectively, 0.37¡Ó0.55 £gmol/m2/h (n=64) and 0.10¡Ó0.53 £gmol/m2/h (n=51). Although the sea-to-air fluxes for methane is much lower than the flux for carbon dioxide, methane emission in the SCS contributes nearly the same greenhouse effect as carbon dioxide does. In Taiwan, the average surface methane concentration in rivers is about 3221¡Ó12386 nM, and the emission is about 104¡Ó337 (£gmol/m2/h) (n=179). The average surface methane concentration and flux are, respectively, 2164¡Ó5432 nM and 265¡Ó1289 £gmol/m2/h (n=120) in the water column in China, including the coasts of Hong Kong , Pearl River and Yangtze River. The average surface methane concentration and flux in the natural water are higher than in Taiwan. In Asia, the average surface methane concentrations of the natural waters are, respectively, 8240¡Ó22753 nM (n=27) and 7639¡Ó24554 nM (n=50) in Thailand and Indonesia, twice the concentration in Taiwan. The average surface methane concentrations of the natural waters are, respectively, 2841¡Ó3358 nM (n=5) and 1939¡Ó3694 nM (n=15) in Malaysia and the Philippines, lower than in Taiwan. The emissions of methane in the natural waters are, respectively, 845¡Ó2622 £gmol/m2/h (n=50), 292¡Ó341 £gmol/m2/h (n=5) and 181¡Ó356 £gmol/m2/h (n=15) in Indonesia, Malaysia and the Philippines, also much higher than in Taiwan. The flux of methane in natural waters in Thailand (100¡Ó265 £gmol/m2/h, n=25) is as the same as in Taiwan.

The purpose of this study was to discuss the CO2 variation in and around the South China Sea (SCS), the largest marginal sea in the world. The SCS and Sulu Sea (SS) in November and December respectively, were a small CO2 source to the atmosphere. The West Philippine Sea (WPS) was a large CO2 source to the atmosphere in September. Due to strong upwelling and mixing in the SCS, the excess CO2 penetrated only to approximately 1000m compared to 1200m in the WPS. Because the SCS subsurface water flows to the SS through the 420 m-deep Mindoro Strait, the excess CO2 in the SS was found throughout the entire water column. According to NOAA, 2002 was a weak-to-moderate strength ENSO year and the second warmest since 1986. The Taiwan Strait is the sole passage which connects the East and South China Seas, but the CO2 variation in the Taiwan Strait is unclear during the ENSO year. We heady discuss the relation between the ENSO and CO2 variation in the Taiwan Strait. During the ENSO year, the Penghu Channel mixed in more Kuroshio water but the upwelling strength weakened. During an ENSO event, the southwest monsoon and surface circulation are weaker than normal, hence there is less SCS water flowing to the Penghu Channel. Primary productivity in the non-ENSO year (2001) was high so the fCO2 was low in the upwelling area in the Penghu Channel. The £G fCO2(sea-air) was about 15µatm and 20µatm in the non-ENSO year and the ENSO year, respectively. The southern Taiwan Strait was a source of CO2 in summer. The hydrology in the northern Taiwan Strait in summer was comprised mainly of two different water masses. A salinity front was found at between 25.67oN, 121.24oE and 25.87oN, 120.95oE in the non-ENSO year and at between 25.67oN, 121.24oE and 25.77oN, 121.08oE in the ENSO year. There was coastal upwelling in the western Taiwan Strait in the ENSO year. In the ENSO year, the southward flowing China Coastal Current in winter (January to March) was weaker than normal, which led to a higher percentage of northward flowing water mass in summer. As a result, the summer time salinity in the surface layer became higher so the vertical density gradient became lower than a normal year. East of the front was the Kuroshio and west of the front was the water mass that flew through the Taiwan Strait. The Kuroshio is high in temperature and salinity so the fCO2 to the east of the front was higher than found west of the front in the non-ENSO year. In the ENSO year, owing to the coastal upwelling, the fCO2 near the Chinese coast was higher than east of the front. The northern Taiwan Strait had a £G fCO2(sea-air) of about 21µatm and 16µatm in the non-ENSO and the ENSO years, respectively, and it was still a source of CO2 in summer.

El Niño 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 Niño 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 Niño, 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 Niño 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.

自從1995年菲律賓與中共在美濟礁發生衝突以來，雙方在南海主權議題上時而緊張、時而和緩。歷經羅慕斯時期(1992年~1998年)的對峙衝撞、埃斯特拉達 (1998年~2001年)的冷靜淡化、亞羅育 (2001年~2010年)的低調迴避，步入艾奎諾三世時期(2010年~)之後訴諸國際法庭的法律戰，菲、中關係轉為對立緊繃。 冷戰後的4位菲律賓總統大致是採行「避險」策略，以便在中、美的拉扯下夾縫求生。菲國的策略揉合了「扈從」與「制衡」的概念，此與東協各國盛行的「大國平衡」策略相近，既要拉攏美國與日本，也要扯進中國大陸。菲律賓國家政策堅守「區域安全仰仗美國」與「經濟發展緊抓中共」兩大主軸，難以避免地會陷入「地緣政治」與「地緣經濟」的角力之中。至於中共在處理與鄰國的南海爭端上，則是秉持「鬥而不破」的原則，對付菲律賓的各種挑釁行為，採取的是「裁剪式」策略，為菲律賓量身打造相應的各種手段與方法。 宥於菲國薄弱的軍事實力，以及菲、美同盟的夥伴關係，可以預期的，在艾奎諾三世任期結束之前，菲律賓在南海議題上仍會不斷發聲，並且以法律戰持續與中共抗衡，以便獲取更多籌碼來維護國家利益。至於艾氏的繼任者，預測將會大幅修補對中關係，擺回「親中」的外交路線。 / Since the Mischief Reef dispute broke out between the Philippines and China in 1995, the relations between the two countries have been unstable when it comes to sovereignty issues over South China Sea. From the confrontation period of Fidel Valdes Ramos (1992~1998), the relaxation strategy of Joseoh Ejercito Estrada (1998~2001), the avoidance attitude of Gloria Macapagal Arroyo (2001~2010), to the Law War Stage of Benigno S. Aquino III (2010~ ), now the China-Philippines relation has turned into an antagonistic one. The 4 Philippines presidents after the end of the cold war have roughly adopted hedging strategies in order to survive from the tug-of-war between China and America. The Philippines employs a strategy that combines bandwagoning and balancing, similar to ASEAN’s equilibrium strategy among big countries, drawing America and Japan over to its side and forcing mainland China to get involved. The Philippine national policy sticks to two principles: “Relying on America for Regional Security” and “Grasping China for Economic Development”. The policy unavoidably makes the country fall into the wrestling of “Geo-Politics” and “Geo-Economics.” As for China, it maintains the principle of fighting over core interests but will not break the relationship. Facing the various provocative actions of the Philippines, China adopts a tailored strategy with corresponding means and methods to handle the Philippines. Due to the weak military capabilities and the alliance relations with America, it is predictable that before Benigno S. Aquino III finish his term as the Philippines president, the country will continue to bark on South China Sea issues and try to contend with China by law so as to obtain more advantages in protecting its national interests. As for Aquino’s successor, predictably he/she will substantially repair the relations with China and regain pro-china policies.