China Sea Area Research Articles

Suitable Area of Invasive Species Alexandrium under Climate Change Scenarios in China Sea Areas

Suitable Area of Invasive Species Alexandrium under Climate Change Scenarios in China Sea Areas

The Morphology, Genetic Diversity, and Distribution of Ulva meridionalis (Ulvaceae, Chlorophyta) in Chinese Seas

Green tides originate from the rapid growth of green macroalgae and their large accumulation. In the past few decades, the severity and frequency of green tides have increased and the range of their geographical distribution has widened. In recent years, Ulva meridionalis Horimoto et Shimada has been reported in many countries. This species has stable morphological characteristics, and its length can reach 3 m in indoor cultures. Its cells contain pyrenoids, and the sporangium and gametangium of each cell contain 8 spores and 16 gametes, respectively, which confer a high proliferation potential. The phylogenetic tree constructed in this study showed that the Internal Transcribed Spacer sequence identified U. meridionalis with a high identification reliability, and the genetic relationship between U. meridionalis and Ulva pertusa in the ITS sequence was close. The haplotype network analysis clarified the relationship of the U. meridionalis samples collected from four different sea areas in China and indicated that they were closely related. Five haplotypes were identified: Hap_2 and Hap_1 were the most frequent, and they were also the haplotypes shared among the three groups. The degree of subspecies formation was not reached among these U. meridionalis samples collected from the Chinese seas. Up to 20 years ago, U. meridionalis had only been recorded in Japan. After 2011, it has been found to be widely distributed in the United States, China, French New Caledonia, French Polynesia, and Australia, where it proliferates. It has spread as a new kind of green tide-forming macroalga. The present study found that U. meridionalis is widely distributed in the Chinese seas; specifically, there have been small-scale blooms in the Bohai Sea, the Yellow Sea, and the South China Sea. Further investigations should focus on establishing whether U. meridionalis will cause large-scale green tide events in the future.

An improved altimeter-derived gravity anomaly from shipborne gravity based on the mean sea surface height constraint factors method

Coastal marine gravity modeling faces challenges due to the degradation of the quality and poor coverage of altimeter data in coastal regions. The effective fusion of shipborne gravity data and altimeter-derived marine gravity data can make shipborne gravity data more useful for the accurate estimation of altimeter-derived coastal marine gravity. A mean sea surface height constraint factor (MSSHCF) method based on the ordinary kriging method and the remove-restore technique is proposed to fuse altimeter-derived gravity model with shipborne gravity data. In this method, all data are standardized during the interpolation process to reduce the error and mean sea surface as a vertical variable is added to the semi-variance function in ordinary kriging to obtain the residual shipborne gravity as corrected data source. The coastal marine gravity models V2.1 and V3.1 which fused altimeter-derived gravity data with shipborne gravity data and V1.1 without shipborne gravity data at a spatial resolution of 1′×1′ can be obtained. Validation experiments show that the accuracy of the gravity model V3.1 obtained by the MSSHCF method more closely agrees with the validated gravity model DTU17 and SS V31 than the model V2.1 obtained by the ordinary kriging interpolation method and the V1.1 model. Our results were validated against shipborne gravity data; the accuracy of model V3.1 was 4.95 % higher than the model V1.1 in South China Sea area A and 2.48 % higher in South China Sea area B. Meanwhile, the accuracy of model V3.1 was 2.07 % higher than model V2.1 in South China Sea area A and 2.42 % higher in South China Sea area B. The effects of distance from the coast and sea depth on the marine gravity model were also evaluated. The results show that the gravity model V3.1 has higher accuracy with the change in ocean distance and depth than the V2.1 and V1.1 gravity models. Thus, our study shows that the MSSHCF method effectively refines coastal altimeter-derived gravity using shipborne gravity data.

Spatio-Temporal Distribution of Giant Jellyfish (Nemopilema nomurai)

In this study, the distribution of giant N. jellyfish by the echo counting method was investigated in the East China Sea, where giant N. jellyfish are known to breed and migrate to the coastal waters of Korea mainly in summer. In addition, the distribution densities by the survey method were compared with the sighting and trawl surveys. In the case of the East China Sea area and the Gijang coastal area, a split beam type scientific echosounder (EK60, Simrad, Norway) and Acoustic data at 38 and 120 kHz were collected while moving at 6–7 kts. In the coastal waters of Korea, acoustics data at 38 and 120 kHz were collected with a split beam type scientific echosounder (EK80, Simrad, Norway) attached to the bottom of the R/V Tamgu No. 21. In the East China Sea, the average distribution densities of acoustic, sighting, and trawl surveys were 8355.7 (10−6 ind/m3), 162.2 (10−6 ind/m3), and 792.5 (10−6 ind/m3), respectively. The average densities in the coastal waters of Korea of acoustic, sighting, and trawl surveys were 2238.7 (10−6 ind/m3), 664.9 (10−6 ind/m3), and 432.9 (10−6 ind/m3), respectively. The average distribution density of the acoustic survey conducted on 21 July 2020 in the coastal waters of Gijang was 1024.5 (10−6 ind/m3), and the sighting survey showed 48.8 (10−6 ind/m3). The sighting surveys conducted on 22 July 2020 were 393.3 (10−6 ind/m3) and 19.6 (10−6 ind/m3). The average distribution density for the acoustic survey performed on 23 July 2020 was 99.0 (10−6 ind/m3), and for the sighting survey was 197.2 (10−6 ind/m3). When comparing the results of the acoustic survey with the results of the sighting and the trawl surveys, all surveys except for the survey conducted on 23 July 2020 showed that the acoustic survey was higher than other survey methods.

Spatio-temporal distribution and mechanism of Cenozoic magmatism in the South China Sea and adjacent areas: Insight from seismic, geochemical and geochronological data

ABSTRACT Cenozoic magmatism was highly active in the South China Sea (SCS), and mostly dominated by basalts. The magmatic rocks are mainly distributed in the lower slope and subbasins of the SCS, in addition to sporadic and small-scale Cenozoic volcanism on the SCS shelf. This paper presents a complete map of the Cenozoic magmatic rocks of the SCS with magmatic rock boundaries. This paper also presents an analysis of geological survey and published data in terms of seismic profiles, ages, geochemistry and isotopic systematics of the Cenozoic magmatic complexes of the SCS and adjacent areas. Many of wells or dredges are located in magmatic rocks identified by seismic profiles. Three periods of magmatic activity are distinguished: (1) a pre-spreading period (>33 Ma); (2) a syn-spreading period (33–15 Ma) and (3) a post-spreading period (<15 Ma). The thickest volcanic rocks encountered more than 1000 m (possibly Oligocene to Miocene) in the Boayan 1/1A well in the Palawan Trough of the southern SCS during Cenozoic. The oldest magmatic rocks are andesites (62.5 ± 2.2 Ma) in the northern SCS (offshore) and andesites (65 ± 3 Ma) in Penghu (on land). The latest modern magmatic activity was detected in 1923 offshore of a submarine volcanic eruption (10°09´29″N, 109°00′50″E, 20 m below sea level) and along the shore of a volcanic eruption in the Philippines. Cenozoic magmatic rocks of the SCS include at least 1008 rock bodies: the smallest is 0.00012 km2, the largest is 1528 km2 and the total area covers 46,309 km2. The Yangjiang-Yitong fault and Zhongnan-Reedbank fault divide the magmatic rocks into two different sections in the eastern and western SCS. The ages of the magmatic rocks in the eastern SCS are mostly older than those in the western SCS. The magmatic rocks in the northern, southern, eastern, western SCS and adjacent areas, and SCS basin are related to extension, subduction+collision, subduction, extrusion, extension+cooling+subsidence, respectively.

NEW STRATEGY JAPANESE MILITARY IN THE ASIA PACIFIC REGION AND THE IMPACT ON INTERNATIONAL SECURITY STABILITY

The purpose of this study was to determine the new Japanese military strategy in the Asia Pacific region and its impact on international security stability. The South China Sea conflict is one of the major conflicts for the Southeast Asia region and also the Asia Pacific region. Japan has a role in supporting countries involved in the conflict such as Vietnam. Japan promised Vietnam six patrol boats during Prime Minister Abe's visit to Southeast Asia.The approach used in this research is a qualitative approach and the type of research carried out is descriptive by explaining certain phenomena systematically, actually and accurately regarding facts, characteristics, and relationships. The patrol boat is aimed at enhancing Vietnam's capability in maritime law enforcement related to the South China Sea conflict. Japan, which is Vietnam's biggest foreign investor after South Korea, has no territorial claims in the South China Sea conflict. The South China Sea region has a big role in geopolitics because it is a meeting point between China and countries within the Association of Southeast Asian Nations (ASEAN) in terms of territory, security, natural resources and energy security. Disputes in the region include territorial sovereignty and maritime sovereignty. The South China Sea area consists of, among others, several small islands that are widely distributed, but there are two groups of islands that are much contested, namely the Spratly Islands and the Paracels. In addition, the South China Sea area is an important shipping lane and is often referred to as the maritime superhighway because it is one of the busiest international shipping lanes in the world.

History and Effect of South China Sea Conflict on Southeast Asia Political Stability

The purpose of this study is to describe the history and influence of the South China Sea conflict on the political stability of Southeast Asia. The South China Sea has tremendous potential, both in the sea and above the sea. Thus, countries in Southeast Asia and the two major world powers, namely the United States and the People's Republic of China, are trying to claim or at least maintain their influence in the region. This research method uses literature research, and data analysis techniques used use content analysis methods. The findings of this study are that mutual claims between countries in Southeast Asia will become a major conflict in the future if it is not resolved. The negotiations were about the process of resolving conflicts that occurred in the South China Sea in reviewing the problems, and prospects in the South China Sea area for the benefit of all countries.

Analysis of Engineering and Geological Conditions of International Submarine Optical Fiber Cable Routing in the East China Sea Section

The East China Sea section of the Chinese international submarine optical fiber cable generally starts from the Shanghai coast, crosses the East China Sea shelf and continental slope to the east, and intersects with the international optical fiber cable system in Okinawa Trough. In this paper, the regional tectonic, seismic, and other environmental conditions of the East China Sea section of the international submarine optical cable are briefly described based on the previous data. Additionally, the geological engineering conditions of the international optical cable routing in the East China Sea area will be analyzed based on the field investigation data such as multibeam, side-scan sonar, shallow stratigraphic profile, sediment sampling, and cone penetration test (CPT). It is found that the main geological factors in the East China Sea shelf area are submarine scouring, sandwave, shallow gas, and hard seabed; in the land slope area are steep slope, submarine valley, rock, landslide, and shallow gas (pockmark); and in the Okinawa Trough area are gully, sea mound/seamount, rock, shallow gas, fault, and hard strata outcrop. This paper briefly analyzes the impact of each geological disaster factor on the submarine cable project and proposes solutions for providing essential information and some scientific basis for designing, constructing, operating, and maintaining international submarine optical fiber cables in the East China Sea area.

Sparse Data-Extended Fusion Method for Sea Surface Temperature Prediction on the East China Sea

The accurate temperature background field plays a vital role in the numerical prediction of sea surface temperature (SST). At present, the SST background field is mainly derived from multi-source data fusion, including satellite SST data and in situ data from marine stations, buoys, and voluntary observing ships. The characteristics of satellite SST data are wide coverage but low accuracy, whereas the in situ data have high accuracy but sparse distribution. For obtaining a more accurate temperature background field and realizing the fusion of measured data with satellite data as much as possible, we propose a sparse data-extended fusion method to predict SST in this paper. By using this method, the actual observed sites and buoys data in the East China Sea area are fused with Advanced Very High Resolution Radiometer (AVHRR) Pathfinder Version 5.0 SST data. Furthermore, the temperature field in the study area were predicted by using Long Short-Term Memory (LSTM) and Gate Recurrent Unit (GRU) deep learning methods, respectively. Finally, we obtained the results by traditional prediction methods to verify them. The experimental results show that the method we proposed in this paper can obtain more accurate prediction results, and effectively compensate for the uncertainty caused by the parameterization of ocean dynamic process, the discrete method, and the error of initial conditions.

Indonesia’s Security Dilemma in the Tension Between the United States and China in the South China Sea Conflict

The South China Sea is known as the second busiest sea lane in the world after the Suez Canal in Egypt, this area also has an abundance of living creatures and has large oil and natural gas reserves. Because of its potential, the area is still a contest for claims between several countries. Currently, it is known that the United States and China are the largest hegemonic countries in the economic field that are fighting for power in the South China Sea region. Some experts even discussed the possibility of competition that will end with war or military conflict in the 21st century. As a result of this tension, other countries in Southeast Asia which are generally not superpowers have put themselves in a situation that is called a security dilemma. Indonesia is not a claimant country in the South China Sea area but has sovereignty near the area which is Natuna Island. If there is a conflict between the United State and China in the South China Sea area, it will have direct implications for the sovereignty of the Indonesian state in Natuna. To deal with this scenario, Indonesia must prepare its defense forces. In this security dilemma situation, Indonesia is strengthening its military and making alliances with other countries that also do not want conflict or war, Indonesia also trying to balance its power with China and the United States with the balance of power strategy. The aim of this article is to describe whether the balance of power strategy that has been carried out by Indonesia is successful as a deterrence strategy.

Study on green output bias of China's mariculture technological progress.

With the rapid development of mariculture, environmental pollution is becoming more and more serious. It is particularly important to study the green output bias of technological progress for the long-term sustainable development of mariculture. Based on the input-output data of the mariculture in 10 Chinese coastal areas from 2008 to 2018, the DEA-Malmquist index decomposition method is used to calculate the output-biased technological progress index and combines with the change of marginal substitution rate of output factors in different periods to identify the bias of technological progress between output factors and analyze the green output bias of mariculture technological progress. The results show that green technological progress is a crucial factor affecting green total factor productivity's growth in China's mariculture. During the study period, the number of regions where technological progress tends to reduce pollutant emissions shows a fluctuating upward trend, and the degree of technological progress toward green output is high. There are obvious differences among regions. The green output bias of technological progress in the South China Sea area is the highest, followed by the East China Sea area, and the Bohai Sea area is poor. Specifically, the green output bias of technological progress in Fujian, Guangdong, and Hainan is higher, while the green output bias of technological progress in Tianjin, Hebei, Shandong, and Guangxi is lower. According to the research results, corresponding policy suggestions are provided to realize the green and sustainable development of China's mariculture.

Sejarah Pulau Siantan sebagai Pusat Aktivitas Bajak Laut dan Daerah Pelarian Politik pada Abad 18 M

This paper discusses the history of Siantan Island (Anambas) in the South China Sea as a center of pirate activity (lanun and political escape areas in the 18th century. The writing uses historical historical research methods and uses library research to extract sources. From the research, it is known that a number of nobles from the Sultanate Siak, the Sultanate of Palembang and the Bugis nobility from Luwu moved to Siantan after losing the power struggle in their native area. In Siantan, the nobles gathered strength by relying on the Orang Laut. The existence of the Orang Laut became the main force to become pirates (lanun), rulers of the sea and carry out piracy in the south China sean and The South China Sea and other areas. The act of piracy ois not only political purposes, but also for economic reasons to seek wealth. Marriage ties are a powerful tool in strengthening relations between the immigrant aristocrats and the Siantan people. The nobles in Siantan then returned to their kingdom and successfully seize power. Raja Alam became the Sultan of Siak, the Five Opu Bugis brothers ruled in the Kingdoms of Johor, Riau and Lingga. Meanwhile, Prince Jayawikrama succeeded in seizing the throne of the Sultan of Palembang with the title Sultan Mahmud Badaruddin I.

DISKURSUS SENGKETA LAUT TIONGKOK SELATAN DI MEDIA SOSIAL TWITTER

This study aims to examine some of the literature on the impact of the South China Sea dispute from the perspective of global communication from the perspective of social media Twitter. The method used is a qualitative approach. This study is to find out how many sources on social media Twitter discuss this global issue and its impact on other countries. The results showed: 1) Since 2012 until now, several sources have discussed the development of studies on the South China Sea Ownership Dispute in the perspective of global communication. Of the many accounts registered on social media Twitter that discuss the issue of the South China Sea, there are 28,031 active authors and 2,412 identified authors who have searched for articles published between the last 5 to 15 years. The results found 21 studies / studies published from Asia, America, and Australia related to the discussion of the South China Sea Ownership Dispute issue from a global communication perspective. The South China Sea dispute is one of the threats that has the potential to have a large negative impact, not only for Indonesia, but also for regional stability in Southeast Asia. 2) The impact arising from the South China Sea Ownership Dispute that I got from qualitative analysis from social media sources Twitter, namely through ASEAN, it is likely that this conflict can be resolved peacefully. In addition, this conflict is able to create global cooperation in several fields between countries regarding the management of the South China Sea area, so that it is expected to be able to calm disputes with the existence of collaborations that build towards a better direction.

Investigation of oyster Crassostrea gigas lipid profile from three sea areas of China based on non-targeted lipidomics for their geographic region traceability

The present study sought to analyze the lipid profiles of oyster Crassostrea gigas from Yellow Sea (YS), East China Sea, and South China Sea (SCS) through the untargeted lipidomics strategy based on UPLC-Q-Exactive Orbitrap mass spectrometry and multivariate statistics. The results elucidated that geographical differences had profound effects on the lipid content, composition, and lipid molecular profiles. Notably, oysters from the YS group contained the highest lipid content, including triacylglycerol, diacylglycerols, and the majority of phospholipid molecule species, while oysters from the ECS group contained most of the phosphatidylcholine species and the SCS group contained most of the sphingolipid species. Totally, 1155 lipid molecular species belonging to 21 subclasses were identified; of them, 45 lipid molecular species could serve as differential marker for lipid of oysters from different sea areas. Overall, lipidomics could be a potential approach for discrimination of lipid characters between marine shellfishes for geographical origin traceability.

Incentive policies for transboundary marine spatial planning: an evolutionary game theory-based analysis

Marine spatial planning (MSP), which is a step-by-step approach for the ecosystem-based management (EBM) of global oceans, enables human activity and marine and coastal ecosystems conservation to occur simultaneously. It contributes to the implementation of the 2030 Agenda, particularly Sustainable Development Goal 14. However, the MSP, supposed as a transboundary policy-making process, is hampered by obstacles. Although existing studies have revealed significant obstacles and enablers for transboundary marine spatial planning (TMSP), they have not analyzed how these factors affect government decision-making. To fill this gap, this paper takes the Xiamen–Kinmen Sea area in China as an example and analyses the interaction between the Xiamen–Zhangzhou–Quanzhou (XZQ) governments, the Kinmen government, and an introduced transboundary institution using evolutionary game theory. Numerical simulation is used to analyse the impact of influencing factors on the behaviors of different actors. The results demonstrate that: (1) the initial probability of the three parties directly affect the final stability; (2) net benefits have a positive incentivizing effect on the performance of the Promotion Group; (3) the value of eco-environmental losses reflects the urgency of collaborative governance by implementing TMSP; (4) transaction costs do not undermine collaboration, but do reduce the willingness of governments to participate if they are too high; and (5) the appropriate value of the transaction cost allocation coefficient should not exceed 0.9. This research may serve as an essential reference for the Xiamen–Kinmen Sea area for implementing EBM and provide general insights into the design of incentive policy recommendations for other regions for developing TMSP in shared waters.

SSR Marker-Based Genetic Resource Assessment of the Rainbow Clam Moerella iridescens Along the Coasts of China: Implications for Strategy of Conservation Management

This study aims to determine the genetic structure of rainbow clam Moerella iridescens in different sea areas of China. Seventeen pairs of microsatellite primers (SSR) were used to amplify the SSRs of rainbow clam in Lianyungang of Haizhou Bay, Chongming of Shanghai, Ningde of Fujian, Daishan of Zhoushan, and Cixi and Wenzhou of Zhejiang. A total of 1,146 alleles were detected in 310 individuals from the 17 SSR loci. The average observed heterozygosity of six populations was 0.4381−0.6139, the average expected heterozygosity was 0.5897−0.7325, and the average Shannon diversity index was 1.2655−1.7998. The clams exhibited rich genetic diversity, and the FST of the genetic differentiation index of the six populations was 0.0470, indicating low genetic differentiation among the populations. The results indicated that rainbow clams along the coasts of China exhibited high diversity and low population differentiation.

Analysis of the Influence of Submarine Operational Capabilities on the State of Deterrence

Indonesia is an archipelagic state whose territory lies in a cross position between two continents and two oceans. So that Indonesia has the authority to maintain the security of its maritime territory, starting from regulating its shipping lanes to maintaining sovereignty in all of Indonesia's sea areas. Indonesia's threats have been identified as coming from neighboring countries, namely Malaysia, Singapore, Thailand, and China. Increasing escalation in the South China Sea area, Efforts to support Indonesian territorial security, submarines currently owned must be able to become a deterrent against potential threats both from within and from outside and be able to operate in all Indonesian waters. The hypothesis in this study is if the operational capability of the submarine increases the country's deterrence system. The methodology used is descriptive quantitative using software SPSS 25 and Microsoft Excel 2013 with data analysis techniques using multivariate correlation. The effect of submarine operational capability on the country's deterrence is 86.6% that implies submarine operational capability has strong influence.

Has Technological Progress Contributed to the Bias of Green Output in China’s Marine Economy?

At present, the destruction of the marine ecological environment and the imbalance of economic structure have put forward urgent requirements for the green development of the marine economy. Based on the input and output data of China’s coastal provinces from 2006 to 2018, the RDM (range directional model) direction distance function was used to measure the output bias technology progress (OBTC) index of each region, and its influence on China’s marine economy green total factor productivity (GTFP) was judged accordingly. Furthermore, the rationality of the current OBTC index was studied. The results show that there is obvious output-biased technological progress in China’s marine economy, and it has led to the improvement of the GTFP. Although most coastal areas still tend to pursue the improvement of the total output value of the marine economy at the expense of environmental damage, the green bias of China’s marine economy has improved significantly since 2015, driven by relevant marine environmental protection policies. From the perspective of different areas, the imbalance of regional development in the process of China’s marine economic development is significant. The green bias of the marine economy is highest in the East China Sea area and lowest in the Bohai rim area. However, the coordination between the development of the green marine economy and environmental protection in the South China Sea area needs to be improved.

The Dynamics of The China Maritime Militia Conflict In South China Sea On Sovereignty Indonesian Countries And ASEAN Region Countries

The South China Sea is a strategic water area and is rich in natural resources. The South China Sea dispute is the hottest dispute in the 21st century, in which China and most ASEAN members are involved indirectly. China's unilateral claim of ownership of the South China Sea area using the nine dash line principle and maritime power has triggered a response from surrounding countries, including Indonesia. For Indonesia itself, its main concern in this conflict is to maintain the security of its country and protect the vulnerable island of Natuna. In this study, we will discuss the dynamics of the China Maritime Militia conflict in the South China Sea against the sovereignty of the Indonesian state and ASEAN countries. This study uses a qualitative method with a literature study approach where the data sources used are journals, articles, books and other relevant sources. Based on the results of the study, it was concluded that the disputes that occurred in the South China Sea were disputes between countries, because the actors were not only claiming countries but also other countries with an interest in the region. Therefore, the strategy taken in efforts to resolve the China Maritime Militia dispute in the South China Sea is to strengthen the capacity of maritime security enforcement and command for various Indonesian maritime law enforcement agencies, and take a free and active approach that is manifested in support and participation in regional organizations such as ASEAN

The Distribution Characteristics of Moho Depth and its Relation with the Tectonic Pattern in South China Sea and Adjacent Areas

The Distribution Characteristics of Moho Depth and its Relation with the Tectonic Pattern in South China Sea and Adjacent Areas