Marine plastic waste has been an important global environmental issue in recent years, and quantifying the amount of global marine plastic waste input is vital for control and mitigation. However, determining an accurate quantity of oceanic plastics is challenging because comprehensive monitoring data are difficult to obtain on national and global scales. To understand the contribution of China in global marine plastic waste input, we used a material flow analysis (MFA) method, which is included in lifecycle assessment and combines statistical data from China’s official statistics, reports, and NPO (nonprofit organization) to establish an MFA model. The model assesses the lifecycle of plastics, which starts with primary plastic, passes the stage of plastic product, and eventually becomes plastic waste. With the MFA model, the annual amount of plastic waste entering the ocean from China from 2011 to 2020 can be calculated. In 2011, 0.65 million tonnes of plastic waste entered the ocean from China, and the quantity rose slowly until 2016. A rapid decline appeared in 2018 because of China’s governmental managements and the quantity will continue to decrease until 2020. Our results indicate the amount of oceanic plastics has a strong correlation with government control measures.

Marine microplastics pollution has been a new challenge to marine environmental protection. The research results have shown that microplastics exist everywhere in the ocean. However, understanding of the transport of microplastics in the ocean, including coastal zones, is not clear. This paper provides a holistic overview of the modelling of microplastic transportation. The transport processes are complex, including surface drifting, vertical mixing, beaching, and settling. Besides the dynamic conditions of oceans, the transportation of microplastics is influenced by their physical characteristics, such as size, shape, and density. For buoyant particles, a Lagrange track model is used to simulate the surface drift process, considering current, windage effect, and Stokes drift. It is difficult to observe the vertical mixing process of microplastics because of their small size (<5 mm), therefore the parameters of the vertical mixing process in the model are still less known. Large accumulation of microplastics in sediments may be a result of settlement and entrainment. Also, biofilm formation can increase their density and thus, deposition. Considering sedimentation of microplastics is somewhat different from sediment deposition, some primary parameters (e.g., diffusivity, Stokes-drift, settling rate, biofouling rate) are required in future studies to better understand the transport of marine microplastics.

Climate-driven adaptive genetic variation is one of the most important ways for organisms to tolerate environmental change and succeed in altered environments. To understand rapid climate-driven evolution, and how this evolution might shift biogeographic distributions in response to global change, we measured the adaptive genetic variation to the local environment of a marine invasive species Mytilus galloprovincialis. The genetic structure of eight populations from the Mediterranean Sea, northeastern Atlantic, northeastern Pacific, and northwestern Pacific were determined using genome-wide screens for single nucleotide polymorphisms. The relationships of genetic variation to environmental (seawater and air) temperature were analyzed using redundancy analysis and BayeScEnv analysis to evaluate the impacts of temperature on the genetic divergences among these eight populations. We found that the genetic compositions were significantly different among populations and the adaptive genetic variation was associated with temperature variables. Further, we identified some genetic markers exhibiting signatures of divergent selection in association with environmental features that can be used in the future to closely monitor adaptive variation in this species. Our results suggest that divergent climatic factors have driven adaptive genetic variation in M. galloprovincialis over the past century. The rapid evolutionary adaptation has played a pivotal role in enabling this species to invade a wide range of thermal habitats successfully. Species like M. galloprovincialis that possess high levels of genetic variation may not only be especially capable of invading new habitats with different environmental conditions, but also poised to cope rapidly and successfully with rising global temperatures.

The morphodynamic responses of tidal networks to anthropogenic reclamation and de-reclamation projects are investigated through a three-stage numerical simulation. In the first stage, the natural development of tidal networks is modelled in an open coast without any anthropogenic interventions. At the beginning of the second stage, parts of the computational domain are enclosed by sea dikes, which represents the implementation of the reclamation project. These sea dikes are removed or opened in the third stage to simulate the recovery of the tidal networks after de-reclamation. Each stage was set to last 100 years. The model results indicate that land reclamation can lead to three effects on tidal network morphology: (i) completely terminating the development of channels inside the projected area, (ii) hindering the development of the channel network in front of the dikes, and (iii) turning the channel direction near the corners of the dikes. When removing all the sea dikes, the previously reclaimed areas are quickly occupied by tidal networks. However, the morphology cannot be fully restored to its original natural state, although the entire reclaimed areas are returned. The effects of opening breaches are relatively slow, and tree-like network structures are formed inside the reclaimed areas.

Marine microplastics are a global problem and are causing considerable concern. As the largest marginal sea of the Western Pacific, the Yellow Sea is surrounded by China and the Korean Peninsula, and its coastal ecosystem is greatly affected by human activities. This article reviews the progress of microplastics research in the Yellow Sea in China, including studies on surface water, the seawater column, sediments, and marine organisms. The results indicate that plastic debris exists throughout the west Yellow Sea, with higher abundance of microplastics in water columns and sediments in the north part than those in the south part. Fibers <1 mm and transparent-colored particles dominated the samples collected. Polyethylene (PE), polypropylene (PP), and cellophane (CP) were the dominant debris types. The wide distribution of microplastics in the environment also results in animal ingestion. Sea cucumbers, accordingly, ingest more microplastic debris than other biologic taxa (zooplankton, shellfish, and fish) that have a bearing on their surrounding environment. By providing basic environmental assessment data regarding the Yellow Sea, this paper demonstrates that actions should be taken to reduce the consumption and emission of plastics into the environment.

The coastal zone is the most concentrated area of human activities, and it is also the main accumulation zone of continental sediments, which is an ideal area for studying anthropocene sedimentary records. This study summarizes the distribution of ^239+240Pu activity, ^239+240Pu inventory, and ²⁴⁰Pu/²³⁹Pu atom ratios in the sediments of the seas and estuaries of China. Studies have shown that the distribution of ^239+240Pu activity in sediments is mainly influenced by sediment properties and ocean current dynamics. Furthermore, ^239+240Pu activity in sediment cores has obvious peak characteristics, which can be used in sediment dating. In fact, ²⁴⁰Pu/²³⁹Pu atom ratios indicate that the Pu in the sediments of the seas and estuaries of China mainly comes from global fallout and the Pacific Proving Grounds (PPG). Pu from the PPG enters the seas of China through the North Equatorial Current and Kuroshio intrusion current. And the contribution of Pu from the PPG in the East China Sea, the South China Sea, and the Yangtze estuary is over 40%. Moreover, Pu has been applied in the tracer of land-sea interactions and ocean dynamics, and it can be used as a background value to study the changes of Pu in the coastal zone of China in the future.

Norwegian fjord systems provide a host of ecosystem services and are important for recreational and industrial use. The biodiversity of Norwegian fjords has been—and still is—extensively studied since they are important for fishing and aquaculture industries. However, threats from plastic and microplastic pollution within the fjord systems are largely undocumented. Monitoring efforts of microplastic in Norway are limited to coastal biota monitoring, offshore sediments, and some investigations within Oslofjord. Here, we quantify anthropogenic microparticles in Norwegian fjord subsurface waters, including an analysis of distribution effects. Fifty-two samples were collected during repeated transits from Bergen to Masfjorden covering 250 km. Anthropogenic particles were identified in 89% of samples, with an average abundance within the fjord estimated to be 1.9 particles m⁻³. This report shows the ubiquitous nature of anthropogenic particles in the subsurface waters of a Norwegian Fjord system. Additionally, methods were validated for opportunistic nondisruptive sampling on-board vessels where microplastics are seldom monitored, including research vessels, commercial freight and transport, and recreational vessels. Further development and implementation of these methods in terms of sampling, chemical characterisation, and long-term monitoring will allow for microplastic quantification and can be easily adapted for worldwide implementation.

Many of the world’s coastlines are vulnerable to erosion and at risk from tidal flooding. Addressing and managing these risks presents major challenges especially when seeking to sustainably balance the requirements for coastal protection with other economic, environmental, and societal objectives. The nature and scale of these challenges varies greatly from site to site and can often be magnified on dynamic shorelines that are subject to a high degree of physical and ecological change. Applying an ongoing process of adaptive management is widely agreed to be a key mechanism for dealing with such dynamic conditions and issues of uncertainty. However, under this process it can be difficult for different stakeholders to reach a consensus about the most suitable intervention actions. In part, this can arise because there is an incomplete understanding about past, present, and, especially, future environmental processes. It can also occur due to differences in the perceptions and priorities of the relevant stakeholders. This paper reviews some of these complexities using, as a case study, recent developments of a shingle spit and tidal inlet at Pagham Harbour, on the south coast of the UK. This example provides lessons in the application of adaptive management and working with nature concepts in a particularly complex coastal setting. This paper considers these lessons in the context of the site’s history, the legal and policy framework, and established understanding about the natural environment.