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Topic Review
Impacts of Blue Economy on Deep-Sea Ecosystem Services
The deep-sea is the most extensive environment on the Earth and is defined as the water column and seafloor below 200 m water depth. The ecosystem services (E.S.) concept comprises ecological functions (e.g., climatic adaptation) and social and economic values (e.g., food security, job creation) that promote human well-being. Deep-sea E.S. comprise the provisioning of services such as industrial agents and fish catch, regulating services such as climatic and biological regulation, and cultural services such as aesthetics and inspiration for the arts. Several studies have shown that deep-sea ecosystems support a large variety of habitats and a wide array of faunal communities with various functions. These complex communities are threatened by the growth of human activities targeting precisely these provided ecosystem services.
  • 780
  • 29 Nov 2021
Topic Review
Mineralogy and Geochemistry of Ferromanganese Crusts
Late Pleistocene–Holocene rocks from the western part of Cocos-Nazca Spreading Centre (C-NSC) include ferromanganese crusts that elucidate the geochemistry and mineralogy of a deep-sea geological setting. Geochemical, mineralogical and petrological signatures indicate complex formation influenced by mild hydrothermal processes. These crusts consist mostly of mixed birnessite, todorokite-buserite, and Mn-(Fe) vernadite with traces of diagenetic manganates (asbolane), Fe-oxides and oxyhydroxides or hydrothermally associated and relatively pure Mn-oxyhydroxides (manganite). The average Mn/Fe ratio is 2.7, which suggests predominant mixed hydrogenous-early diagenetic crusts with hydrothermal influences. The mean concentrations of three prospective metals (Ni, Cu and Co) are low: 0.17, 0.08 and 0.025 wt %, respectively. The total content of ΣREY is also low, and ranges from 81 to 741 mg/kg (mean 339 mg/kg).
  • 762
  • 27 May 2022
Topic Review
Τhe “GPS/GNSS on Boat” Technique
The opening up of the global positioning system (GPS) for non-military uses provided a new impetus for the study of the sea surface topography (SST) and geoid, especially in coastal areas which are important from the viewpoint of the climate crisis. The application of the “GPS/GNSS on boat” method, as an alternative to traditional (indirect and direct) methods, has provided detailed SST maps in coastal and oceanic areas with an accuracy of up to few centimeters.
  • 701
  • 06 Jan 2023
Topic Review
Biological Influence of Aerosol Nutrients
The aerosol contains major ions, heavy metals, and organic matters that are important external nutrients in upper oceans and potentially influence marine microbes and biogeochemical cycles. Therefore, the role of atmospheric deposition to oceans has received growing attention. 
  • 693
  • 15 Jun 2022
Topic Review
Resistivity Logging Progress of Marine Gas Hydrate
Marine gas hydrate has accumulated special characteristics, such as greater water depth, non-diagenesis, and irregular and uneven distribution. These characteristics lead to great challenges in gas hydrate evaluation and exploitation. The free gas layer is often developed below the bottom boundary of the submarine hydrate stability zone.
  • 672
  • 26 May 2022
Topic Review
Multi-Use of the Sea
Conserving and sustainably uing oceans, seas, and marine resources constitutes one of the key Sustainable Development Goals (SDGs) of the United Nations Agenda 2030. The key issue in this context is an amplification of human utilization of marine space and the latter’s more extensive exploitation for economic purposes. As a result, marine sea space is becoming a scarce resource, requiring careful management, and can no longer be perceived as infinite and abundant. Maritime multi-use could as a territorial/SPATIAL governance instrument for the enhancement of sustainable development in five EU sea basins. Multi-use (MU) is expected to enhance the productivity of blue economy sectors, as well as deliver additional socio-economic benefits related to the environmental and social dimensions of sustainable development. 
  • 634
  • 11 Aug 2021
Topic Review
Upwelling in Marginal Seas
Upwelling refers to the upward movement of deep nutrient-rich and low-temperature waters to the surface, resulting in colder surface or near-surface waters with low dissolved oxygen, high density, and high salinity. Upwelling is economically and ecologically significant in the coastal marine system, making it high-priority research. Although representing <1% of the total surface area of the ocean, upwelling regions provide approximately 8% of the global marine primary production and more than 20% of the world’s capture fisheries. With an increase in offshore transport, strong upwelling usually transports phytoplankton and zooplankton towards the convergence offshore frontal system rapidly, relative to a weaker upwelling that limits the nutrient enrichment in the photic zone. Apart from boosting primary productivity and fishery production, upwelling is also crucial for the atmosphere-ocean carbon dioxide exchange and carbon recycling processes.
  • 612
  • 04 Aug 2023
Topic Review
Coastal Environments and Representative Ports of NWIP
Ports significantly impact the economic activity in coastal areas. Future climate change projections indicate that the frequency and intensity of extreme sea levels (ESL) will increase, putting several port facilities at risk of flooding with impacts on the port’s reliability and operability. The northwest Iberian Peninsula (NWIP) coast is crossed by one of the most important and busiest shipping lanes in the Atlantic Ocean and features several ports that provide an essential gateway to Europe. Some of the NWIP ports can be considered representative of the different geomorphological environments that characterise the NWIP coast: the ports of Aveiro (lagoon), Lisbon (estuary), Vigo (Ria) and A Coruña Outer Port (marine).
  • 607
  • 08 Mar 2023
Topic Review
Remote Sensing and Monitoring of Marine Pollution
With the rapid development of urbanization and industrialization, human activities have caused marine pollution in three ways: land source, air source, and sea source, leading to the problem of marine environments. Remote sensing, with its wide coverage and fast and accurate monitoring capability, continues to be an important tool for marine environment monitoring and evaluation research.
  • 517
  • 07 Nov 2023
Topic Review
Wave Energy Generation in Brazil
Seas and oceans offer great potential as a widely available source of clean and renewable energy near high energy consumption centers. This source of energy is a valuable option in the energy transition and in energy matrix decarbonization. Wave energy and an oscillating water column (OWC) device stand out as the types of ocean energy with the most potential. An onshore OWC requires locations with rocky outcrops and steeper slopes as the device needs to be physically installed and has lower energy dissipation due to friction with the seabed. However, Brazil has approximately 7490 km of coastlines, with various shoreline geometries and geomorphologies, some of which are very suitable for OWC implementation.
  • 502
  • 27 Oct 2023
Topic Review
Hyperbolic Barriers in Geophysical Flows and Their Extraction
Transport barriers are material surfaces across which the transport is minimal. They can be classified into elliptic, parabolic, and hyperbolic barriers. Hyperbolic barriers are less evident. They are the most influential repelling and attracting material lines (or surfaces in 3D cases) with the strongest local stability, which can be identified in real oceanic and atmospheric flows by calculating the maximal Lyapunov exponents. The transport barriers are fundamental features controlling the movement of anthropogenic and natural pollutants, plankton, cross-shelf exchange, and the propagation of upwelling fronts in coastal zones.
  • 409
  • 23 Oct 2023
Topic Review
Oceanic Environmental Impact in Seaports
Seaports are gateways that connect a nation to the world economy. With trade by sea increasing due to globalization, the need for the improvement and development of seaports cannot be overlooked. While the development of ports is considered essential for the economic growth and prosperity of a nation, they also result in environmental deterioration that can hurt the future of humanity.
  • 359
  • 06 Dec 2023
Topic Review
Satellite Altimetry for Ocean and Coastal Applications
More than 30 years of observations from an international suite of satellite altimeter missions continue to provide key data enabling research discoveries and a broad spectrum of operational and user-driven applications. These missions were designed to advance technologies and to answer scientific questions about ocean circulation, ocean heat content, and the impact of climate change on these Earth systems. They are also a valuable resource for the operational needs of oceanographic and weather forecasting agencies that provide information to shipping and fishing vessels and offshore operations for route optimization and safety, as well as for other decision makers in coastal, water resources, and disaster management fields. This time series of precise measurements of ocean surface topography (OST)—the “hills and valleys” of the ocean surface—reveals changes in ocean dynamic topography, tracks sea level variations at global to regional scales, and provides key information about ocean trends reflecting climate change in our warming world. Advancing technologies in new satellite systems allows measurements at higher spatial resolution ever closer to coastlines, where the impacts of storms, waves, and sea level rise on coastal communities and infrastructure are manifest. 
  • 332
  • 24 Aug 2023
Topic Review
Gas Plume Target Detection in Multibeam WCI
A multibeam water column image (WCI) can provide detailed seabed information and is an important means of underwater target detection. However, gas plume targets in an image have no obvious contour information and are susceptible to the influence of underwater environments, equipment noises, and other factors, resulting in varied shapes and sizes. 
  • 327
  • 29 Jun 2023
Topic Review
Application of Coastal-Area Morphodynamic Models
Human activity has become an important force in coastal and estuarine morphological changes. Understanding the morphodynamic impact of these human activities has attracted the attention of scientists as well as coastal and estuarine managers. From the perspective of ecosystem conservation and restoration, scientists and managers require modelling approaches to assess and predict the impact of anthropogenic activities on coastal and estuarine morphogenetic evolution.
  • 303
  • 19 Jul 2023
Topic Review
Shipowners’ Choices of Alternative Marine Fuels
It is interesting to find that alternative fuels (e.g., liquefied natural gas) are the most attractive choice for gas ships and ro-ro carriers; others prefer to use conventional fuels. Furthermore, shipowners’ choices of new fuels significantly correlate with their nationality is revealed. While it is well-established that economic factors influence shipowners’ choices for new ship fuel solutions, the impacts of bunker costs, freight rates, and CO2 emission allowance prices remain relatively limited. It is evident that the policies of the International Maritime Organization (IMO) to reduce carbon emissions have increased the demand for building new energy ships. 
  • 299
  • 23 Oct 2023
Topic Review
Phytoplankton as Indicators of Climate Change
Phytoplankton represent a taxonomically diverse group of photosynthetic, mostly single-celled aquatic organisms that drift with the current. Phytoplankton also play an important role in influencing the Earth’s climate and the functioning of the biological carbon pump. The biological carbon pump is a major component of the global carbon cycle and refers to the process by which atmospheric CO2 is transferred by primary producers (mostly phytoplankton) from the eutrophic zone of the ocean to the underlying sediments.
  • 241
  • 10 Jan 2024
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