The current industrial production of hydrogen basically comes from fossil energy. Under the background of carbon emissions peak, the utilization of hydrogen energy has to be greener and more convenient .The production of hydrogen from abundant seawater resources seems to be a promising way. This paper reviews the research and development status of hydrogen production from seawater in China and abroad in recent years, and summarizes the overall research progress of hydrogen production by direct electrolysis and photolysis of seawater respectively. Then, it introduces the industry development status of hydrogen production from desalinated seawater. Finally, the future development of hydrogen production from seawater is prospected. It is discovered that great challenges exist since direct hydrogen production of seawater is still in R&D and test stage. The hydrogen production from desalinated seawater need to resolve problems in complex process through industrial demonstration. The future of hydrogen production from seawater is based on hydrogen demand, electricity cost and technical feasibility. Under certain circumstances, hydrogen production from seawater may usher in development opportunities.

The 10 ASEAN countries (Indonesia, Thailand, Singapore, the Philippines, Malaysia, Brunei, Vietnam, Laos, Myanmar, and Cambodia) play an important role in the international energy market and energy geopolitics with their abundant oil and gas resources and crucial geographical position. Based on the comprehensive analysis of the current situation of ASEAN countries' oil and gas development, strategies, relevant projects, and international cooperation, it is discovered that Indonesia, Malaysia, Vietnam, and Brunei have more advantages in marine oil and gas reserves and utilization than other ASEAN countries. In addition to making national investment, these countries are actively attracting international investment to make up for the technical and financial constraints on the exploration and utilization of offshore oil and gas. However, as the growing demand for oil and gas has far exceeded the output of ASEAN countries, many countries are transforming to net oil and gas importers. Accelerating the exploration and development of deep-water oil and gas resources, applying digital technology, taking measures to improve energy efficiency, and developing renewable energy is becoming the opportunities for ASEAN countries to promote the sustainable development of energy, and also providing opportunities for China to strengthen the cooperation with ASEAN countries in the energy area.

Russia is a traditional large marine country. A practical understanding of its marine research activities will help China develop marine science and technology. Based on laws, strategies, plans and projects, this paper makes a qualitative analysis on the objectives, policy orientation and main fields of Russian marine research activities. It is considered that the top-level design of marine research activities in Russia is relatively complete and has significant top-down characteristics. Russia's marine research aims to serve national interests and help maintain its status as a major maritime power. Russia's marine research activities involve the world's oceans, focusing on the inland sea, territorial sea and adjacent waters, Arctic and Antarctic. In terms of the research field, Russian research covers not only basic exploratory issues such as marine physics, marine chemistry and marine geology, but also the research and development of applied technologies such as shipbuilding science, marine development equipment, scientific research facilities and information, security and life support systems to ensure marine research activities. China should base itself on reality, speed up the marine legislation and the formulate China's strategy of Antarctica and Arctic, improve the layout of research forces focusing on regions and specialties, and strengthen the construction of independent and controllable marine technology chain, so as to promote the initiative of "Maritime Silk Road" and develop marine economy.

Among the major marine countries in the world, the United States attaches the most importance to ocean science and technology development strategic plan. In the 21st century, the United States has released two decadal plans to lead the development of its ocean science and technology. The first is Charting the Course for Ocean Science in the United States for the Next Decade: An Ocean Research Priorities Plan and Implementation Strategy (2007—2017), and the second is Science and Technology for America’s Oceans: A Decadal Vision (2018—2028), they determined the direction for the U.S. ocean science and technology development in the new historical period. Through comparative analysis, it is found that great changes have taken place in U.S. ocean science and technology goal, general guideline and priorities. The goals of ocean science and technology have shifted to serve the needs of national development. The general guideline of "one system", "two topics" and "three key concepts" has been clearly put forward. The research priorities have transferred to the applications of ocean science and technology in understanding the ocean, promoting economic prosperity, ensuring maritime security, safeguarding human health and developing resilient coastal communities. Finally, four suggestions are put forward for the development of China’s ocean science and technology in the future, and hopefully they could provide reference for building China into a maritime power. It is proposed that China should strengthen the research and development of forward-looking ocean technology and accelerate the construction of ocean research infrastructure, highlight the role of ocean science and technology in promoting economic prosperity and ensuring maritime security, develop a collaborative and efficient ocean ecological environment technology system and enhance the capability of monitoring, early warning and emergency response to ocean ecological disasters and maritime emergencies, and maximize the use of ocean big data to improve ocean perception, prediction and decision supportability.

NSFC plays an important role in promoting China's basic scientific research. In the past decade, China’s investment in Marine Science Fund has maintained a rapid growth. This paper compares the basic situation of National Natural Science Foundation of China (NSFC) and National Science Foundation, United States (NSF) in the field of marine science from 2007 to 2019, including project quantity, funding amount, etc. Choosing the SCIE papers produced by the projects that are funded by NSFC and NSF in Marine Science as the research objects, this paper explores the differences in the quantity, quality and research topics of the papers produced by these projects, analyzes the differences of NSFC and NSF’s funding theme in the field of marine science, and then reveals the effects of NSFC’s funding in this field. The results show that the fund input in the field of marine science in China has increased greatly; the number of papers published and the average influence of papers are positively correlated with funded projects’ grants; the number of NSFC-funded output is higher than that of NSF, but the average influence of papers of NSFC-funded output still lags behind the international level; Both NSFC and NSF have the same funding direction and paper output theme, but the funding focus is significantly different. NSFC-funded research focuses on coastal waters, such as the South China Sea, East China Sea, Yellow Sea, centering on marine natural products, taxonomy, remote sensing and ecological disasters; NSF-funded research focuses on the Gulf of Mexico, Southern Ocean and Atlantic Ocean, centering on coral reef ecosystem, climate change, deep-sea hydrothermal vents, ocean acidification and biogeochemical cycles. Basically，NSFC funding covers hot research issues in the marine field. It is suggested that in the future, NSFC funding should strengthen international scientific and technological cooperation, expand research areas, and increase funding in areas such as ocean hypoxia, biogeochemical cycle and deep sea.

Identifying and analyzing the hotspots and development status in the field of Ocean Engineering and Technology can provide important information for the development of related industries in China. With CiteSpace software, this paper identifies hotspots through the keyword clustering and frequency growth analysis of literature and patent data in the field. Then, through the S-shaped growth curve, the technology maturity is obtained, and the Innojoy patent value index is used to analyze the technical competitiveness, so as to determine the development stage and trend of the hotspots. The results demonstrates eight current technology hotspots in Ocean Engineering and Technology including engine and propulsion, power equipment, target detection and prediction, anti-corrosion coatings, radar systems, oil and gas exploration and processing, motion and structural response, and renewable energy development. Based on the historical development and the international competitiveness of these hotspots, it is suggested that China should research and develop independently and maximizing the value of the industrial chain for the less competitive technology in the mature stage, broaden the market and continuously improve the product performance and service level for the competitive technology in the growing stage, and stabilize the market, simplify the system and integrate the technology for highly-competitive technology in the mature stage.

Turbine is an important mechanical structure in the process of ocean energy transformation and utilization, which can convert the kinetic energy of the fluid into rotating mechanical energy and drive the generator operation to generate electricity, which has been widely used in the field of Marine energy power generation. In the traditional sense, the blade turbine structure is a little bit complex, easy to use the working media leakage and other problems, which will greatly reduce the efficiency of turbine use. Tesla turbines due to simple structure, low manufacturing tolerance requirements, good sealing and other advantages are back in the eyes of researchers, and the operating performance of Tesla turbines determines the level of energy conversion efficiency, through the study found that Tesla turbines are not yet high conversion efficiency, in engineering practice applications can not be widely used, so it is particularly important to improve the efficiency of tesla turbines. This paper summarizes and analyzes the factors affecting the performance of Tesla turbines, introduces the mechanical structure, application field and research status of Tesla turbines, lists the experiments and studies carried out by researchers at home and abroad on Tesla turbines, summarizes the numerical simulation methods of Tesla turbines, provides some reference basis for improving the energy conversion efficiency of Tesla turbine and in future practical application, and finally looks forward to the application prospects of Tesla turbines in small marine energy utilization devices.

Autonomous underwater vehicles (AUV) are important tools for exploration and development of Marine resources. AUV's advanced navigation and control, communications, sensors and other technologies have enabled humans to make a big leap in understanding the ocean. The control system is the core component of the underwater vehicle, which is also the key to determine whether the working state of the underwater vehicles are stable and reliable. The paper summarizes and analyzes the development process and research status of AUV at home and abroad, introduces the control technology of AUV and summarizes the causes of the difficult control of AUV. The main control technologies of AUV are systematically discussed, and the basic principles of several main control methods are briefly introduced. At the same time, the motion control of AUV are further analyzed in detail, which can provide some certain references for the selection of the operation control methods, the design of the corresponding controllers and the construction of the control system for underwater vehicle. Finally, the potential application of the continuous advancement of AUV's development technology in the future marine development field is prospected.