Because of their unique habitat and metabolic pathways, marine microorganisms can produce a variety of bioactive substances with novel structures and functions, which make natural products from these marine microorganisms become a research hotspot of new marine drugs. Combining the methods and perspectives of bibliometrics, we review in this paper the research status of natural products from marine fungi and marine bacteria, the artificial synthesis of natural products of marine microorganisms, the biological activity and druggability evaluation of natural products from marine microorganisms, to clarify the current status and development trend of natural products from marine microorganisms.

Mangroves are salt-tolerant plants of tropical and subtropical intertidal regions distributed mainly between latitudes 25°S and 25°N globally. They have high productivity, high return rate, high decomposition rate, and high resistance, which cover roughly 60%-75% of the world’s tropical coastlines. Mangroves are distributed over more than 118 countries with a total area near 17 million hectares in the world, and their net primary productivity is up to 2000 gC·m^-2·a^-1. They form a widespread ecosystem and also play an important role in the process of global change. Global climate change has aroused great concerns in the last three decades. Mangroves are a vulnerable and eco-sensitive ecosystem along tropical and subtropical intertidal shores that are regulated by both lands and oceans. They are one of the typical marine ecosystems that can be affected by global climate change. As an important ecological barrier along the coast, global climate change will also affect the survival and distribution of mangroves in the world. The present paper briefly reviews the impacts of global climate change on mangroves in terms of global warming, sea-level rise, atmospheric CO₂ concentration increase, and extreme weather. The ongoing global climate change will bring great challenges and opportunities to research, maintenance, and development of mangroves in the future.

Ocean dynamic processes in the South China Sea driven by the monsoon are characterized by seasonal and multi-scale variations, which have significant impacts on the evolution of marine ecosystems. Marine bacteria, as an important component of material cycle and energy flow in marine ecosystems, have active responses to the environmental changes associated with multi-scale dynamic processes. The interdisciplinary research on microbial community structures, their dynamic variation and associated physical processes is one of the hot issues in marine sciences, which combines marine microbiology, microbial ecology and physical oceanography. Based on the primary results of the Key Research Program, "Study on bacteria diversity coupled with the monsoon circulation in the South China Sea and significance in microbial oceanography" supported by the National Natural Science Foundation of China, we discuss in this paper current research progress, including coastal upwelling, seasonal thermal fronts, mesoscale eddy, sub-mesoscale processes, and their potential impacts on the marine bacterial diversity and local ecosystem in the South China Sea.

Environmental pollution is serious in the Pearl River Estuary due to human activities and an increasing attention has been paid to the pollution in this region. This paper mainly reviews the eutrophication characteristics and the pollution patterns of persistent toxic substances (PTS, including heavy metals and persistent organic pollutants—POPs) in the water. Results in-dicate that the excessive input of nitrogen and phosphate has led to the high eutrophication in the water. Eutrophication plays an important role in triggering red tides. The coupling effect of the water stratification and eutrophication leads to the seasonal hypoxia in certain areas of the estuary. PTS mainly accumulate in sediment and organisms. The records of pollutants in sedi-ment cores reflect that pollutant accumulation in sediments is closely related to the rapid economical development of the Pearl River Delta in the past three decades. Finally, the critical issues of research are put forward on the environmental pollution of this area in the future, which include biotransformation of pollutants in tissues and bioaccumlation in food chain, the combined pollution of various pollutants in eutrophic water, mechanisms of microbial biodegradation of pollutants, pollution control strategy, among others.

The traditional mangrove land-based enclosure aquaculture model originated in the Pearl River Delta is a good example showing how mangroves can be used sustainably. This paper introduces three examples of mangrove land-based enclosure aquaculture at the mouth of the Pearl River Estuary. The first example is about the only operating traditional mangrove land-based enclosure for shrimp farming located in Mai Po Marshes Nature Reserve of Hong Kong and managed by WWF Hong Kong; its history goes back to the mid-1940s and its focus for management strategy has evolved from being commercial culture ponds to performance of multi-ecological functions including feeding habitat for piscivorous water birds, bird-watching, environmental education, as well as shrimp farming. The second example is the mangrove land-based enclosure for traditionally extensive aquaculture trial in the Dawei Bay on the Qi’ao Island of Zhuhai City, regarding measurement and analyses of relationship between the environmental condition change of water level and salinity and the mangrove community dynamics inside land-based enclosure. The third example is the mangrove planting-aquaculture system trial in the Shenzhen Waterlands Resort on the east coast of the Lingdingyang Estuary, including research on water purification function by mangroves. For mangrove protection and management and for marine pollution prevention in the Pearl River Estuary waters, the following suggestions are given: 1) Preventing resolutely the development model of clearing mangrove for aquaculture ponds, and disseminating and applying the eco-development model of land-based enclosure aquaculture or mangrove-friendly aquaculture; 2) Building new land-based enclosure aquaculture demonstration site in major mangrove regions, and exploring mangrove-friendly restoration model in aquaculture pond areas built by clearing mangroves; 3) strengthening relevant scientific research for maximizing comprehensive efficiency of mangrove land-based enclosure aquaculture.

The Chinese probably first had the name of the South China Sea (pronounced as “Nanhai” in Chinese, where “Nan” means “south”, “hai” means “sea”) in writing at the time of Wuwang Period (1046 BC-1043 BC) during the Zhou Dynasty. “Nanhai (place name)”, was named for its closeness to the South China Sea (Nanhai), which clearly suggests that the term “Nanhai (place name)” was used later than the term “Nanhai (sea name)”. During Chengwang Period (1042 BC-1021 BC) of the Zhou Dynasty, the famous tribute of black millet (Indian millet), known as the story of “Millet of Nanhai”, was from the “Nanhai (place name)”. In Xuanwang Period (827 BC -782 BC) of the Zhou Dynasty, the name “Nanhai” used in the poem Jiang Han includes both the “Nanhai (sea name)” and “Nanhai (place name)”, which was the first time the name was used in writing. “Nanhai” was then used in Yu Gong of Shang Shu in late Zhanguo Period (475 BC -221 BC), but whether it meant the “Nanhai (sea name)” or not has yet to be confirmed. “Nanhai” was later used in Hai Nei Dong Jing of Shan Hai Jing during the Qin (221 BC -207 BC) and Han (206 BC- AD 220) Dynasties; it was also used in Nan Yue Lie Zhuan of Shi Ji and in an ancient map of early Western Han Dynasty (206 BC- AD 8), where it was definitely referring to the “Nanhai (sea name)”, just like its present meaning. From the Eastern Han Dynasty (AD 8-220) to the Tang (AD 618-907) and Song (AD 960-1279) Dynasties, the “Nanhai” was referred as the “Zhanghai”. Over the Ming (AD 1368-1644) and Qing (AD 1644-1911) Dynasties, the “Nanhai” was called the “Daminghai” and “Daqinghai” by foreigners. Then the “Nanhai” was translated as the “South China Sea” by foreigners and the name “South China Sea” has been widely used all over the world. Unfortunately, some Chinese translate the English name “South China Sea” directly into Chinese as the “Nanzhongguohai”, which is then used by some books, magazines and media. The “Nanhai” was first found and named by Chinese around 3 000 years ago, which has been well recognized all over the world. The “Nanhai” is the only name used in official publications and maps by the most recent governments of China. The “Nanhai” is also the only name used in the related administrative departments, armed forces and institutions. Therefore, the “Nanhai” should not be called the “Nanzhongguohai”. People using the name “Nanzhongguohai” can be considered ignorant to Chinese history, which may mislead people to think that the “Nanhai” (South China Sea) was first found and named by foreigners, and further confuse the Chinese sovereignty on the Nanhai.

Over the last two years, Chinese scientists from the both sides of the Taiwan Strait and from overseas, met several times to discuss the direction of deep-sea research in China. All agreed that the South China Sea should be the first priority, and a preliminary sketch of research program of the “The South China Sea Deep” was drafted. The overarching goal of the proposed program is to unveil “the life of a marginal sea”, from three major perspectives: (1) evolution of the oceanic crust in the deep basin, which will be revealed by validating the magnetic anomalies in the South China Sea using new techniques, implementing deep-water drilling of the oceanic crust, and systematically investigating the volcanic mountain chains in the basin; (2) deep-sea sedimentation, including observation of the modern deep-water currents and benthic sedimentation, and reconstruction of sediment response to the evolution of the marginal basin; and (3) biogeochemical processes to be approached by exploring the dynamics and consequences of subsurface fluid circulation, and by evaluating the microbial contribution to the deep-sea carbon cycling. Research breakthroughs are expected in the South China Sea on the basis of nation-wide cooperation with a combined effort by the scientific and engineering communities.

Slow and ultraslow spreading ridges are the key areas for studying interplay among magmatism, tectonics, and hy-drothermal circulation comparing to the fast spreading ridges. Their complicated three-dimensional (3D) seismic structures are the basis of finding their tectonic dynamic mechanism. The research on the 3D seismic structures is reviewed in terms of slow spreading ridges in deep oceans, including its developing international research trend. The new experiments have detected a magma chamber or a melt body at a slow spreading ridge, same as at a fast spreading ridge. The 3D seismic survey for the first time was carried out on the southwest Indian Ocean Ridge from January to March in 2010. The key research aspects are then put forward based on these seismic experiment data. Its preliminary disposing result of the seismic data indicates that the high quality of the seismic data is the strong foundation of the 3D tomography. It is promising to make breakthrough in mechanism on ultraslow spreading ridges. The research will surely promote the Chinese status in the field of international ocean ridges.

Polybrominated diphenyl ethers (PBDEs) are a new type of persistent organic pollutants, which are widely distrib-uted in the marine environment and are harmful to marine organisms. It is, therefore, necessary to assess the effect of PBDEs on marine ecosystems. We introduce the chemical behaviors of PBDEs in seawater, review the accumulation of PBDEs in marine organisms including plankton, benthic animals and nekton, and present the transfer of PBDEs along the marine food chain (web) and their toxic effects. In addition, future research on the marine ecological effects of PBDEs is proposed.

Dredged sediment is the main accumulative site of terrigenous pollutants going into the sea and main potential source of marine pollution. During the course of dredging and marine dumping, these pollutants in the dredged sediment can be released into the sea again, which can harm the marine environment. Therefore, treatment to turn the contaminated dredged sediment into harmless material has significant importance to the scientific management of marine dumping and the effective protection of the sea. The aim of this study is to review six main dredged sediment decontamination and treatment technologies, such as chemical and biosurfactant leaching, thermal treatment, electrodialytic method, ultrasound method, flotation method and bioremediation. The authors discuss the mechanisms of these technologies, effective factors, advantages and deficiencies. Combining several of treatment techniques such as physical, chemical and biological processes is a potentially effective way to treat the polluted dredged sediment in the near future.

The development of marine sciences depends on observations. Satellite is one of the most important observation platforms for marine research. Satellite data are of great significance in marine research. Since the beginning of this century, China has successfully launched several satellites dedicated to ocean observations, and preliminarily established a global ocean satellite observation system. According to the basic situation of marine satellite resources at home and abroad, we study and analyze the current situation of the application and development of marine satellite data in China, especially in terms of receiving, processing, management and application of marine satellite data, put forward the scientific research demand for satellite data in China's marine research, and probe into the existing problems and development strategies of the scientific application of marine satellite data in China.

Creseis acicula, also known as sea butterfly, is marine gastropod adapted to pelagic life. C. acicula is a warm-water marine species and widespread in the world. C. acicula blooms have been found in many waters of the world, particularly in the Indian Ocean. Its bloom was never recorded in the seas of China until 2020. From June to July 2020, an unprecedented outbreak of C. acicula was observed the southwest coast of Daya Bay, Southern China Sea. This bloom lasted for approximately one month. The peak density was as high as approximately 5600 ind·m^-3, which is the highest value ever recorded in the world. The C. acicula population was most abundant in waters adjacent to the outflow of Daya Bay nuclear power plant (NPP) located at the southwest of the bay. The outbreak puts a serious threat to the safety of the NPP operation, and therefore has attracted great attentions from the government, scientists and the public. We conducted a continuous monitoring on this event. Since there is very limited information on outbreak mechanisms, we briefly reviewed related research on bio-ecological characteristics of C. acicula; then, we introduced its development progresses in Daya Bay and preliminarily discussed the possible triggers for this outbreak. We assume that the temperature rise due to thermal discharge from the cooling water of the NPP, the fluctuation of seawater salinity caused by rainfall, and the increase in phytoplankton concentration could be the possible factors for this C. acicula bloom.

Special sedimentary phenomena such as sediment waves in the northeastern South China Sea (SCS) are closely related with physical processes in deep sea. Marine geological studies infer that sediment waves are caused by upward flow, contour current and turbidite current, while westward propagation of nonlinear internal waves and westward movement of meso-scale eddies are main features observed by satellite in the region. The evolutions of eddies and internal tides/internal waves are controlled by seafloor relief, and key features are submarine ridges (Hengchun Ridge and Luzon submarine volcanic arc) and continental shelf edge, which are mainly controlled by tectonic processes. The setup and evolution of modern physical process in SCS Deep are related to the formation and development of deep sea basin, northern rifted margin and eastern subduction margin of the SCS. Comprehensive studies of interactions among tectonic, sedimentary and physical processes will ensure a better understanding of evolution of SCS Deep. Recently, seismic oceanography has developed fast, though still in its preliminary stage. New discoveries may change our traditional knowledge about the deep ocean, grasp the nature of interactions between fluid Earth and solid Earth, and make major contributions to Earth system sciences.

Microbe-mediated nitrification is an essential part of global nitrogen cycle; and nitrite-oxidizing bacteria (NOB), which catalyze the second step of nitrification, have received more and more attention recently. Up to date, those isolated NOB have been identified as four phyla, belonging to seven genera. Among them, Nitrospira bacteria become a hotspot for research due to the high diversity and wide ecological distribution. In this paper, we reviewed the composition, phylogenetic relationship, nitrite oxidizing and carbon fixation pathways of NOB. We also emphasized the functional importance on global nitrogen and carbon of NOB, and highlighted research prospect for NOB.

Coral reefs play vital roles in the construction, protection, and adhesion of reefs, and they protect coastal and national territories as well. Coral reefs have also been considered as tropical rainforests in the marine ecosystem with their abundant biodiversity. More than 200 species of coral reefs exist in the South China Sea; however, some of them have been severely damaged due to natural climate change and human activities in recent years, which threats marine and island safety. Therefore, ecological restoration for coral reef ecosystem is necessary and urgent. In this paper, we summarized the status of coral reefs, technical progress of ecological restoration, and important issues of coral reefs. Furthermore, a novel multidimensional restoration model based on system integrity was proposed and applied in restoring coral reefs, which may provide a new way to restore marine ecosystem.

The South China Sea (SCS) is one of the biggest marginal seas in western Pacific Ocean. Research on its deep crustal structures would improve our knowledge on tectonic attributes of the conjugate continental boundaries, the formation and evolution of the SCS, and formation mechanisms of oil- and gas-bearing sedimentary basins. The deep seismic survey areas can be divided geologically into northern continental margin, southern continental margin, and the central deep ocean basin. The deep seismic experiments of crustal studies have gone through three stages, namely, the sonobuoy, two-ship expanding spread profile (ESP), and ocean bottom seismometer (OBS). Especially in the past two decades, OBS surveys flourished from northern to southern SCS, then moved to the central SCS. The survey patterns developed from 2D straight lines to 3D grid lines. These surveys and studies have provided invaluable information on deep crustal structures and evidence for the formation and evolution theories of the SCS. They have also pushed applications of domestically-made OBS and training of our scientific teams. The 3D OBS surveys in the deep ocean basin just finished recently marks a new historical progress and will have profound scientific impact on future research.

The South China Sea (SCS) is the largest marginal sea in the western Pacific Ocean, connected with the western Pacific Ocean and the Indian Ocean through a series of straits. Multi-scale dynamic processes of ocean circulation and their environmental effects on marine biology and ecology have been a focus of SCS regional oceanography research. Since the first national marine census at the end of the 1950s, China has kept on increasing its support on marine research, especially on the construction of marine scientific observation platforms on research vessels. Entering the New Millennium, the main marine research institutes and universities in China, which operate research vessels, organized and supported Open Cruise for domestic scientists without charging for the shiptime. As a milestone, the Natural Science Foundation of China (NSFC) set up a Shiptime Sharing Project to support the Open Cruise since 2009, which has further promoted communications and cooperations among the domestic ocean research communities. Many important achievements have been made in the SCS regional oceanography. From the perspective of multi-scale ocean dynamics, we briefly review the history of ocean observations in the SCS and summarize the research progresses of key scientific issues in the SCS in recent years, including the water exchange between the SCS and western Pacific Ocean, the mesoscale and sub-mesoscale processes, the multi-scale interaction and its ecological environmental effects, among others. We also share some thoughts and prospects on observations and scientific investigations in the SCS in the future.

Anaerobic oxidation of methane (AOM) by archaea in marine sediments is gradually recognized by scientists and is regarded as an important biogeochemical process performed by both methanotrophic archaea and sulfate-reducing bacteria. Our analysis of 16S rRNA showed that multiple kinds of Methanoarchaea including AEME-1, AEME-2 and AEME-3 were the players in the AOM process, and these Methanoarchaea were distributed widely in the oxygen minimum zone of the open ocean. Furthermore, AOM process is related to the global environmental change closely. Most methane leaked from cold seeps of deep sea was consummated by Methanoarchaea in the course of penetrating the deposition layer of anoxic zone; so emission of strong greenhouse methane was reduced greatly. The studies of AOM biogeochemical process should be significant for understanding the formation mechanism of clod seep carbonate, controlling the leaking methane from seafloor, exploitation of combustible ice, and so on.

As the largest marginal sea in the western Pacific, the South China Sea (SCS) plays an important role in the global ocean and the global oceanographic research. In the past 40 years, chemical oceanographic research in the SCS achieved systematic new discoveries and new understandings; researchers put forward many new theoretical viewpoints, making important contributions to the development of oceanography. A subsurface layer was revealed in the SCS, maximum values of ecological environmental parameters represented by nitrite are present; and the depth ranges of water layers for different parameters are different, forming a thermocline ecosystem that has significantly different characteristics from the other ecosystems. The carbon cycle process in the SCS is very complex, and changes of the biological pump controlled by biological activities, and the regional and seasonal changes of carbon sources and sinks, are all great. The characteristics and intensity of carbon sources and sinks in the SCS are unique in different regions at different times. Annually, the SCS is a weak source of atmospheric carbon dioxide. The characteristics of ecological environment and the cycling process of chemical material in the Pearl River Estuary and deep-sea basins were found not only closely related to but also significantly different from that in shelf marginal seas and coral reefs, as the dissolved oxygen concentration is low in the bottom, and the Pearl River Estuary is basically an ecologically fragile area characterized by hypoxia. Based on the systematic understanding of the rapid material circulation and vertical transfer of chemical substances controlled by biological processes in the Nansha coral reef ecosystem, a new mechanism - “resembling drift-net theory” - was proposed to explain how the coral reef ecosystem could maintain high productivity. Systematic studies on the sedimentary chemistry of the SCS show that there is a close coupling between the sediments and chemical cycling of water bodies. The distribution of chemical substances in coral reefs or in sediment cores of the SCS can be used to retrieve historical environment changes. The paleo productivity of surface seawater in the SCS during the glacial period was 1.6 times higher than that of the interglacial period. A "biological explosion event" occurred in the southern SCS in the late Miocene. The productivity in that period was mainly affected by the monsoon and terrigenous nutrients input, while the influences of northeast monsoon and southwest monsoon differed in different regions. These new discoveries and new understandings in chemical oceanography of the SCS in the past 40 years have laid a strong foundation for further systematic and in-depth understanding of the oceanographic processes in the region. In the future, chemical oceanographic research will definitely provide scientific support for the sustainable utilization of resources and environment in the SCS.

Mangrove is one of the most important ecological and environmental resources in the world, which can have significant effects including reservation of the organic carbon, accretion of the tidal flat, and protection from ocean hazards. In this study, we reviewed studies of the mangrove tidal flat (MTF) sedimentary dynamics, which involve damp energy and sediment trapping of the MTF, bio-geomorphological behavior of the MTF, and response of the MTF to storm and sea-level rise. We stress that understanding of the MTF sedimentary dynamics should focus on the following scientific questions: attenuation of the coupled dynamics between wave and tidal current along MTF, coupling processes among hydrological dynamics, deposition, geomorphology, and vegetation. Moreover, it is urgent that the study of regional-scale sedimentation processes and driving mechanics of MTF should be intensified in future.

Seagrass growing in the waters of tropical, subtropical and temperate oceans is an important structural and functional component of the global marine ecosystem and has a high ecological service value. Seagrass is rapidly declining worldwide because of the strong impact of human activities and natural disasters. Therefore, it is a great significance to monitor and protect seagrass resources. With the development of sensor technology, optical remote sensing has shown obvious advantages in seagrass monitoring. In this paper, we review the research status of advanced seagrass remote sensing monitoring at home and abroad, mainly summarizing the research content, technology and methods, and demonstrating the feasibility of seagrass optical remote sensing monitoring. Our aim is to illustrate the suitable data and reliable technical methods for seagrass optical remote sensing monitoring in China, and to suggest potential research directions. This review provides reference for seagrass remote sensing monitoring and expands the thought of scientific management of seagrass resources in China.

Food resources are crucial for the survival and reproduction of marine animals. The trophic niche of marine organisms refers to the ecological roles and functions in marine ecosystem. It plays an important role in studying interspecific relationship, resource partitioning, community structure and function. In this study, by collecting the relevant research on trophic niche of marine animals, we review current research methods (stomach content analysis, bulk tissue stable isotope analysis, fatty acid profiles and compound-specific isotopic analysis) and their applications by focusing on their corresponding ecological models on quantitively evaluating the breadth and overlap of the trophic niche. Moreover, potential development and directions for further studies are presented, with the aim of providing supports for future research on feeding ecology of marine animals.

With the support of the Ministry of Science and Technology, China joined the International Ocean Drilling Program (IODP) in 1998. IODP-China has so far led the organization of 4+1 expeditions. Through the complimentary proposal project (CPP), Chinese scientists led the drilling expeditions of 349/367/368/368x to investigate the full history of rifting- breakup-spreading of the South China Sea (SCS) basin. In this paper, we summarize the latest achievements of IODP Expeditions 367/368/368x, which revealed surprising evidence for abundant magma intrusion and underplating at the distal northern margin of the SCS as well as rapid continent-ocean transition. Extensive in-depth exchanges and cooperation with the international scientific community have greatly enhanced the operation of ocean drilling platforms, management of the IODP organization, scientific and technical staff training, and public outreach. These experiences will further enhance international cooperation of China's oceanographic research.

Typical tropical marine ecosystems are composed of unique habitats and organisms, such as coral reefs, mangroves and seagrass beds. These ecosystems are mainly distributed in tropical and subtropical marine areas worldwide. It is characterized by high material cycling efficiency, unique ecological functions, rich biodiversity and extremely high productivity, and thus a key object of marine scientific research and resource utilization. Under the multiple pressures of human activities and global changes, its degradation trend has become increasingly prominent. How to restore the function of these typical ecosystems and maintain their sustainable development for the benefit of mankind has attracted increasing amounts of attention from the academic community and the international society. In this paper, the distribution patterns, degradation trends and influencing factors of such typical marine ecosystems in the world are described, with an emphasis on the distribution patterns and biodiversity characteristics of coral reef, mangrove and seagrass bed ecosystems in China. Focusing on coral reef ecosystems, this paper discusses the causes of degradation in the ecosystems and relevant action measurements for restoration and protection in China. According to the global action plan for biodiversity conservation and the actual situation of China, countermeasures and suggestions for the restoration, reconstruction and protection of the typical marine ecosystems were proposed: 1) Establishment of a research center for typical ecosystems in the South China Sea, an intelligent monitoring system and database, and an expert think tank; 2) establishing a demonstration zone for the restoration and protection of the typical marine ecosystems, and inviting experts from multiple disciplines to work together on research-experimentation-demonstration-estimate--promotion-monitor; and 3) optimizing policies and regulations, strengthening law enforcement and management, increasing efforts in science popularization and education, raising public awareness of environmental protection, and promoting conscious social actions. This study aims to provide references for strengthening the conservation and management of typical marine ecosystems and biodiversity, maintaining their sustainable development and implementing the 30×30 goals of the Kunming-Montreal Global Biodiversity Framework.

Mangrove endophytic fungi has evolved a unique metabolic pathway due to its high salt, high temperature, strong light and anoxic living environment, and then produced a large number of secondary metabolites with rich species, novel structure and significant activity, making the secondary metabolites of mangrove endophytic fungi a research hotspot in recent years. In the field of mangrove endophytic fungi, Aspergillus and Trichoderma are two genera that have been studied frequently. This paper reviews the recent advance on the chemical structure and biological activity of new secondary metabolites of the endophytic fungi of genus Aspergillus from mangrove from January 2018 to October 2022 and the endophytic fungi of genus Trichoderma from mangrove from January 2015 to October 2022, summarizes them by polyketones, alkaloids, terpenoids and other compounds, and highlights the challenges in the current research. It can provide reference and guidance for the future study of mangrove endophytic fungi.

Coral reef ecosystems are important components of marine ecosystems and play a crucial role in maintaining marine ecological balance and biodiversity. This article summarizes the current international and domestic development status of coral reef ecology through literature review. The major international research focuses include global change and coral reef ecosystems, establishment and maintenance of coral symbiosis, development and evolution of coral reef biotic systems, coral reef biodiversity and species distribution patterns, as well as coral reef ecosystem conservation and management. The major domestic research focuses include global change and coral reef ecosystems, coral-algal symbiosis under global change, diversity of coral symbiotic relationships, human activities and the South China Sea coral reef ecosystem, and coral reef biodiversity and community patterns. The future development trends in coral reef ecology research will emphasize the coral and coral reef ecosystems under the context of global change, coral symbiotic mechanisms, marginal coral reefs, and coral reef conservation and restoration. Future research in coral reef ecology in China should enhance global perspectives, strengthen domestic and international collaborations, explore underlying mechanisms, improve systematic research, and enhance coral reef conservation and restoration studies.

Microbial nitrogen fixation is a crucial part of nitrogen cycling in mangrove ecosystems, it plays an essential role in the nitrogen nutrient supply and primary productivity improvement of ecosystem. This paper reviewed the diazotrophic community structure, nitrogen fixation rate, and the main measurement methods of nitrogen fixation in mangrove ecosystems. We also explored the application of nitrogen-fixing microorganisms in mangrove restoration and the ecological indicators of nitrogen-fixing microorganisms for mangrove habitats, emphasized the vital roles of diazotrophs in coupling carbon, nitrogen, and sulfur cycles in mangrove wetlands, and highlighted new perspectives for nitrogen-fixing microorganisms in the mangrove ecosystem.

Green sea dyke represents a new concept of coastal defense, which combines traditional engineering structure with coastal ecosystem, to cope with the future trend of sea level rise and storm intensification. Before its application, however, the feasibility of such a system must be tested for low-lying coastal areas, where the risk of storm surge, storm-induced waves and shoreline erosion is greatest. The major issue is associated with the process of wave attenuation by the ecosystem and the way of using the ecosystem within the sea dyke system. For many years, wave energy dissipation has been an important research field for tidal flats, a typical environment of low-lying coasts, as well as beaches and rocky coast environments. Theoretical analysis, field observation and physical-mathematical modelling show that the coastal ecosystem indeed plays a significant role in wave energy dissipation: (1) resuspension and fluid mud movement dominate over bed friction in the mud area, in terms of wave height reduction; (2) wave attenuation occurs due to bed friction and bedload transport on the silt-sand flat at the lower part of the tidal flat, while on the upper mudflat it is caused mainly by re-suspension and suspended, fine-grained sediment transport; (3) in the vegetated ecosystems such as salt marsh, mangrove and seagrass beds, the efficiency of plants in reducing flow velocity and dissipating wave energy is higher than that of bare flats, due to plant morphological resistance and stem movement; and (4) wave attenuation is high when passing through biological reefs (e.g., coral and oyster reefs), especially during storms, with bed surface friction and wave breaking being the major mechanisms. Although the wave attenuation theory has been established, the optimization of the way the ecosystem is used within the sea dyke system requires further investigations, especially the techniques of ecological niche reconstruction on eroding coasts and the design of the sea dyke to improve structure safety. The relevant scientific problems include: adaptive biology for salt marsh plants and oysters in conjunction with hard engineering; stability of ecosystem in response to future environmental change; spatial configuration of ecosystem in the green sea dyke and the match between the ecosystem life cycle and the temporal scales of storm events; and the optimization of the sea dyke configuration, on the basis of the equilibrium coastal profile theory.

The health of aquaculture ecosystem and the ecological effects of aquaculture activities have been paid increasing attentions in recent years. As an important part of marine aquaculture ecosystem, ciliates play a key role in matter cycling and energy flow in aquaculture water. In this paper, the research progress about ciliates in mariculture water was reviewed. The biodiversity of ciliates, ciliates diseases, the impact of aquaculture activities on ciliates, and the indication of ciliates to aquaculture environment were introduced. In addition, the limitations of past studies are considered, and the potential research hotspots are prospected for ciliates in aquaculture. This review is aimed at providing some updated information on the ecological effects of mariculture and offering available reference for further understanding the ecological role of ciliates in mariculture.

Sea Cucumbers play an important role in marine ecological system and have edible and medicinal values. At present, wild resources of sea cucumbers are greatly depleted in China, and artificial breeding of sea cucumbers provides an essential way to restore the population resources. Understanding the hormones that regulate spawning behaviors of sea cucumbers has great significance for the development of artificial injection hormone. We reviewed the hormones found in sea cucumbers that can regulate their spawning behaviors, and we also provide some new perceptions for the future research. The review can provide some valuable references for revealing the key spawning mechanism of sea cucumbers and developing the artificial spawning induction by injecting hormones.