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Because of its distinct function and geographic conditions, the impact of climate change on the operation, safety, and income of airports in coastal areas is becoming increasingly significant. The measurement of climate resilience can help identify priority needs and measures to adapt to climate change, which is a crucial step in developing an aviation adaptation plan. At present, the concept of climate resilience is relatively complex and lacks a clear uniformity of composition, which has made it challenging to effectively support the development of adaptation strategies. Based on the definition of climate resilience, our first step was to construct an evaluation system for coastal airports to visually represent the level of climate resilience. Next, in this study, we introduced a coupling coordination and obstacle degree model to analyze the coordinated development and key drivers of climate resilience, which could be used to develop a targeted improvement strategy based on the calculation results. In the future, additional measures can be combined from the natural environment, socioeconomics, governance capacity, and climate change risk to enhance the capacity development of the aviation industry to address climate change and foster the establishment of a sustainable development model between the industry and the environment. [ABSTRACT FROM AUTHOR]

Introduction: Bivalve aquaculture is an important pillar of China's fisheries, with over 1 million tonnes of scallop shells produced annually. However, most of these shells are directly discarded into the sea, leading to continuous pollution of the marine and coastal environments, especially the coast of Yantai in the Bohai Sea where a large number of discarded scallop shell have accumulated. Methods: To trace the fate of scallop shells in the ocean, this study established a model for the transport of scallop shells, coupling a two-dimensional tidal current model using the adjoint method with a Lagrangian particle model. By simulating nested tidal models, the distribution of tidal residual current in the Yantai coastal region was obtained. Then, a Lagrangian particle model was used to track the transport pathways of pollutants in the sea. Results: Driven by the residual current calculated from the tidal model with the actual situation, possible pollutant release areas were inferred. The results of Lagrangian particle tracking experiments indicate that pollutants were released from the upstream accumulation area, specifically the area near Penglai Hulushan, confirming previous speculation. Discussion: The scallop shells transport model can accurately simulate the spatiotemporal profile of scallop shells, which is helpful for managing scallop shell resources and improving the level of shell reuse. [ABSTRACT FROM AUTHOR]

Basking sharks (Cetorhinus maximus) seasonally aggregate in coastal surface waters of the North Atlantic, providing opportunities for visual observation. While putative courtship displays have been observed, actual copulation has not been documented. Here we examine video collected by an unmanned aerial vehicle (“drone”) of novel behavioral interactions between basking sharks in Cape Cod Bay, Massachusetts in May 2021. The behaviors, including close following and tight concentric circling, are consistent with pre‐copulatory behavior observed in other shark species. These observations provide new insights into the pre‐copulatory behavior of basking sharks. [ABSTRACT FROM AUTHOR]

Coastal nutrient loads from point sources such as rivers are mostly well-monitored. This is not the case for diffuse nutrient inputs from coastal catchments unconnected to rivers, despite the potential for high inputs due to intensive land use. The German Baltic Sea coastline consists of numerous peatlands that have been diked and drained. However, some of the dikes have been removed in order to re-establish the hydrological connection to the Baltic Sea, restore local biodiversity, and promote natural CO2 uptake. Since these peatlands were used for agriculture, their rewetting may release accumulated nutrients, leading to nutrient export into the Baltic Sea and intensified coastal eutrophication. Data on these potential nutrient exports are mostly lacking. Therefore, this study investigated nutrient exports from two former agricultural, coastal peatlands: Drammendorfer Wiesen, rewetted in 2019, and Karrendorfer Wiesen, rewetted in 1993. Nutrients (NO3–, NO2–, NH4+, PO43–), nitrous oxide (N2O), particulate organic matter (POM, comprising POC and PON; δ13C-POC), chlorophyll-a, and nitrification rates were analyzed in surface water and porewater sampled weekly to monthly in 2019 and 2020 to compare the effects of different time scales after rewetting on nutrient cycling and potential exports. NH4+, NO2−, and PO43− concentrations were higher in the porewater than in the overlying water at both sites, while nutrient concentrations were generally higher at the recently rewetted Drammendorfer Wiesen than at the Karrendorfer Wiesen. NO3− concentrations in porewater, however, were lower than in the overlying water, indicating NO3− retention within the peat, likely due to denitrification. Nitrification rates and N2O concentrations were generally low, except for a high N2O peak immediately after rewetting. These results suggest that denitrification was the dominant process of N2O production at the study sites. Both peatlands exported nutrients to their adjacent bays of the Baltic Sea; however, N exports were 75% lower in the longer-rewetted peatland. Compared to major Baltic Sea rivers, both sites exported larger area-normalized nutrient loads. Our study highlights the need to monitor the impact of rewetting measures over time to obtain accurate estimates of nutrient exports, better assess negative effects on coastal waters, and to improve peatland management. [ABSTRACT FROM AUTHOR]

Our study meticulously pursued its objectives through a strategic data-gathering approach and a thorough analytical evaluation. In the data collection phase, we undertook an exhaustive accumulation of geographical and environmental information, utilizing high-resolution satellite images and diverse thematic maps. We employed GIS-based models and the Analytical Hierarchy Process (AHP) to effectively determine the most suitable areas for urban development. These models pinpointed zones along the coastal areas and nearby plains, spanning 198.89 square kilometers or 8.25% of the total study area, as highly appropriate for development due to their potential for desalination and tourism, and proximity to vital infrastructure such as the forthcoming NEOM airport and high-speed railway connections. The findings from the Southwestern NEOM model corroborate with NEOM's strategic goals, especially validating the chosen location for The Line. This location is considered ideal due to its accessibility, terrain suitability, and capability to incorporate renewable energy and sustainable water management, thereby supporting the strategic aims and placement of the initiative. This not only highlights the strategic positioning of these areas but also aligns with the Saudi Vision 2030, fostering economic diversification and sustainable development. Together, these actions have established a comprehensive framework for urban planning that respects environmental conservation and promotes sustainable development objectives. By incorporating socio-economic and cultural factors, our research offers a well-rounded approach to urban development, ensuring that new infrastructure is both environmentally considerate and strategically situated to promote enduring growth and community wellbeing in Southwestern NEOM. [ABSTRACT FROM AUTHOR]

The use of Uncrewed Aerial Vehicles (UAVs) is becoming a preferred method for supporting integrated coastal zone management, including cultural heritage sites. Loko i′a, traditional Hawaiian fishponds located along the coastline, have historically provided sustainable seafood sources. These coastal cultural heritage sites are undergoing revitalization through community-driven restoration efforts. However, sea level rise (SLR) poses a significant climate-induced threat to coastal areas globally. Loko i′a managers seek adaptive strategies to address SLR impacts on flooding, water quality, and the viability of raising native fish species. This study utilizes extreme tidal events, known as King Tides, as a proxy to estimate future SLR scenarios and their impacts on loko i′a along the Keaukaha coastline in Hilo, Hawai′i. In situ water level sensors were deployed at each site to assess flooding by the loko i′a type and location. We also compare inundation modeled from UAV-Structure from Motion (SfM) Digital Elevation Models (DEM) to publicly available Light Detection and Ranging (LiDAR) DEMs, alongside observed flooding documented by UAV imagery in real time. The average water levels (0.64 m and 0.88 m) recorded in this study during the 2023 King Tides are expected to reflect the average sea levels projected for 2060–2080 in Hilo, Hawai′i. Our findings indicate that high-resolution UAV-derived DEMs accurately model observed flooding (with 89% or more agreement), whereas LiDAR-derived flood models significantly overestimate observed flooding (by 2–5 times), outlining a more conservative approach. To understand how UAV datasets can enhance the resilience of coastal cultural heritage sites, we looked into the cost, spatial resolution, accuracy, and time necessary for acquiring LiDAR- and UAV-derived datasets. This study ultimately demonstrates that UAVs are effective tools for monitoring and planning for the future impacts of SLR on coastal cultural heritage sites at a community level. [ABSTRACT FROM AUTHOR]

Assessing breakwater damage following intense storm events is crucial for preventing failures that can compromise safety and service quality. This study focuses on assessing the impact of a severe storm event that took place in November 2022, resulting in significant damage to the Amalfi breakwater in Campania, Italy. The breakwater damage and repair armor unit volumes have been evaluated with an integrated approach consisting of a combination of Differential Global Navigation Satellite System (DGNSS) surveys and Unmanned Aerial Vehicle (UAV) photogrammetry. The assessment of the added areas gained for the breakwater reconstruction has been performed using the UAV. The final goal was to estimate a damage parameter to give an assessment of the breakwater stability and to find a rapid and cost-effective method to evaluate the necessary rehabilitation works. The method, being relatively rapid, can also be applicable in the immediate aftermath of a storm surge or even as a systematic monitoring of the breakwater conditions. The findings of the study highlight the importance of monitoring coastal structures to prevent failure mechanisms from occurring in response to future, increasingly frequent and intense storm events. [ABSTRACT FROM AUTHOR]

In the oceanic surface layer, particulate organic carbon (POC) constitutes the biggest pool of particulate material of biological origin, encompassing phytoplankton, zooplankton, bacteria, and organic detritus. POC is of general interest in studies of biologically-mediated fluxes of carbon in the ocean, and over the years, several empirical algorithms have been proposed to retrieve POC concentrations from satellite products. These algorithms can be categorised into those that make use of remote-sensing-reflectance data directly, and those that are dependent on chlorophyll concentration and particle backscattering coefficient derived from reflectance values. In this study, a global database of in situ measurements of POC is assembled, against which these different types of algorithms are tested using daily matchup data extracted from the Ocean Colour Climate Change Initiative (OC-CCI; version 5). Through analyses of residuals, pixel-by-pixel uncertainties, and validation based on optical water types, areas for POC algorithm improvement are identified, particularly in regions underrepresented in the in situ POC data sets, such as coastal and high-latitude waters. We conclude that POC algorithms have reached a state of maturity and further improvements can be sought in blending algorithms for different optical water types when the required in situ data becomes available. The best performing band ratio algorithm was tuned to the OC-CCI version 5 product and used to produce a global time series of POC between 1997-2020 that is freely available. [ABSTRACT FROM AUTHOR]

In the North Pacific Subtropical Gyre, which is one of the largest oligotrophic regions, there is a lack of information regarding the sources and transport of trace metals through water mass mixing. Rare earth elements (REEs) are essential for tracing lithogenic sources and water mass transport. In this study, we present dissolved REE concentrations and the factors controlling their distributions in the northwest Pacific during a GEOTRACES cruise (GP09). In the surface water along 11°N, we observed input signals from the Philippine and the Hawaiian Islands, characterized by positive Eu anomalies and slightly elevated REE concentrations. By incorporating our data and published REE data from the northwest Pacific to the southeast Pacific (40°N–40°S), we demonstrated that the REE concentrations and Yb/Nd ratios can distinguish North Pacific Intermediate Water (NPIW), Antarctic Intermediate Water (AAIW), and modified AAIW. By estimating the ratio of water mass mixing, we suggest that heavy REEs are predominantly contributed by water mass mixing (e.g., 93 % ± 4% for Yb) and can be used as semi-conservative tracers to quantify the mixing of NPIW and modified AAIW at the potential density of 27.2 kg/m3. At ∼800 m depth at stations K12, K13, and K14, weak negative Ce anomalies (>0.1) were observed, indicating the lateral transport of water masses imprinted with sediment signals from the Philippine Islands. In the deep waters (>1500 m) at the Luzon Strait (station K1), we propose that the weak Ce negative anomalies (>0.08) and low Yb/Nd ratios (<5), combined with the low beam transmission, are the result of particle resuspension and release. In deep water (>2000 m), combining high-resolution REE measurements with water mass analysis, our research reveals that dissolved REEs (except Ce) are dominantly controlled by water mass mixing (e.g., 80 %∼100 % for Yb and 70 %∼100 % for Nd). For the non-conservative behavior, which is not explained by water mass mixing, the residual fraction of heavy REEs (<20 % for Yb) originates from release of sinking particles (organic matter and siliceous particles), while the remaining concentrations of light REEs (<30 % for Nd) may be influenced by a combination of particle release and scavenging processes. These findings highlight valuable information about lithogenic sources and the proportions of REE distributions that are controlled by physical and biogeochemical processes. Moreover, it emphasizes the applicability of heavy REEs as effective tracers for understanding basin-scale water mass mixing in the northwest Pacific. [ABSTRACT FROM AUTHOR]

LiDAR bathymetry provides an efficient and comprehensive way to capture the topography of water bodies in shallow water areas. However, the penetration depth of this measurement method into the water column is limited by the medium water and water turbidity, resulting in a limited detectability of the bottom topography in deeper waters. An increase of the analyzable water depth is possible by the use of extended evaluation methods, in detail full-waveform stacking methods. So far, however, this has only been investigated for water depths of up to 3.50 m due to water turbidity. In this article, the potential of these extended data processing methods is investigated on an alpine mountain lake with low water turbidity and thus high analyzable water depth. Compared to the standard data processing, the penetration depth could be significantly increased by 58%. In addition, methods for depth-resolved water turbidity parameter determination on the basis of LiDAR bathymetry data were successfully tested. [ABSTRACT FROM AUTHOR]

Ship collision avoidance has always been a concern and it is crucial for achieving safe navigation of ships at sea. There are many studies on ship collision avoidance in open water, but less attention on coastal waters considering the uncertainty of target ships due to the complexity of the environment and traffic flow. In this paper, collision avoidance decision-making research in coastal waters considering the uncertainty of target ships was proposed. Firstly, accurate ship trajectories are obtained by preprocessing the raw Automatic Identification System (AIS) data. Subsequently, the processed trajectories are clustered using the Ordering Points to Identify the Clustering Structure (OPTICS) algorithm and Hausdorff distance, acquiring a dataset for trajectory prediction of target ships. Then, a mixed Gaussian model is utilized to calculate the prior probability distribution of the prediction model, thus establishing a trajectory prediction model that considers the uncertainty of the target ship. Finally, ship maneuverability is simulated using the Mathematical Model Group (MMG) and Proportion Integration Differentiation (PID) models, and a collision avoidance decision-making model for ships is constructed. The proposed algorithm has been tested and verified in a case study. The results show that the approach effectively predicts the trajectory of the target ship and facilitates informed collision avoidance decision-making. [ABSTRACT FROM AUTHOR]

Widespread hypoxia occurs seasonally across the Oregon continental shelf, and the duration, intensity, and frequency of hypoxic events have increased in recent years. In hypoxic regions, iron reduction can liberate dissolved Fe(II) from continental shelf sediments. Fe(II) was measured in the water column across the continental shelf and slope on the Oregon coast during summer 2022 using both a trace metal clean rosette and a high‐resolution benthic gradient sampler. In the summer, Fe(II) concentrations were exceptionally high (40–60 nM) within bottom waters and ubiquitous across the Oregon shelf, reflecting the low oxygen condition (40–70 μM) at that time. The observed inverse correlation between Fe(II) and bottom water oxygen concentrations is in agreement with expectations based on previous work that demonstrates oxygen is a major determinant of benthic Fe fluxes. Rapid attenuation of Fe(II) from the benthic boundary layer (within 1 m of the seafloor) probably reflects efficient cross‐shelf advection. One region, centered around Heceta Bank (~ 44°N) acts a hotspot for Fe release on the Oregon continental shelf, likely due to its semi‐retentive nature and high percent mud content in sediment. The results suggest that hypoxia is an important determinant of the inventory of iron is Oregon shelf waters and thus ultimately controls the importance of continental margin‐derived iron to the interior of the North Pacific Basin. [ABSTRACT FROM AUTHOR]

The eastern subpolar North Atlantic is a source of nutrients to the Northwest European Shelf and Arctic; however, biogeochemical transports in this important region are unknown. We examine variability in nutrients and carbon at the eastern boundary of the subpolar North Atlantic between 2017 and 2020, and calculate their transport by a branch of the North Atlantic Current and the European Slope Current. By combining observations from moorings and ship‐based surveys, we derive novel biogeochemical property transports at high temporal resolution. Data from 63 m provide new evidence of a strong seasonal signal with silicate declining between April and May (− 2.3 μmol kg− 1 ) and a concurrent increase in pH (0.04) and oxygen saturation (3.5%). Additionally, pH and oxygen saturation show a secondary peak in October during the autumn bloom. Biogeochemical transports are northwards and highly variable with volume transport dominating the variability over a multi‐annual timescale. However, historical data suggests that nitrate and phosphate transports were 15% and 19% lower respectively in the late 2000s when the subpolar gyre circulation was weaker and lower nutrient source waters were dominant. These changes may have been amplified by concurrent reductions in volume transport. Changes in carbon and nutrient transports in the eastern subpolar North Atlantic may propagate downstream with potential effects on the Northwest European Shelf and Eurasian Arctic. [ABSTRACT FROM AUTHOR]

This paper addresses the intricate challenges of coastal management, particularly in rapidly forming tidal flats, emphasizing the need for innovative monitoring strategies. The dynamic coastal topography, exemplified by a newly formed tidal flat in Shanghai, underscores the urgency of advancements in coastal risk recognition. By utilizing a digital twin framework integrated with state-of-the-art unmanned aerial vehicles (UAVs), we systematically evaluate three configurations and identify the optimal setup incorporating real-time kinematics (RTK) and light detection and ranging (LiDAR). This UAV configuration excels in efficiently mapping the 3D coastal terrain. It has an error of less than 0.1 m when mapping mudflats at an altitude of 100 m. The integration of UAV data with a precise numerical ocean model forms the foundation of our dynamic risk assessment framework. The results showcase the transformative potential of the digital twin framework, providing unparalleled accuracy and efficiency in coastal risk recognition. Visualization through Unity Engine or Unreal Engine enhances accessibility, fostering community engagement and awareness. By predicting and simulating potential risks in real-time, this study offers a forward-thinking strategy for mitigating coastal dangers. This research not only contributes a comprehensive strategy for coastal risk management but also sets a precedent for the integration of cutting-edge technologies in safeguarding coastal ecosystems. The findings are significant in paving the way for a more resilient and sustainable approach to coastal management, addressing the evolving environmental pressures on our coastlines. [ABSTRACT FROM AUTHOR]

Inundation of coastal stormwater networks by tides is widespread due to sea‐level rise (SLR). The water quality risks posed by tidal water rising up through stormwater infrastructure (pipes and catch basins), out onto roadways, and back out to receiving water bodies is poorly understood but may be substantial given that stormwater networks are a known source of fecal contamination. In this study, we (a) documented temporal variation in concentrations of Enterococcus spp. (ENT), the fecal indicator bacteria standard for marine waters, in a coastal waterway over a 2‐month period and more intensively during two perigean spring tide periods, (b) measured ENT concentrations in roadway floodwaters during tidal floods, and (c) explained variation in ENT concentrations as a function of tidal inundation, antecedent rainfall, and stormwater infrastructure using a pipe network inundation model and robust linear mixed effect models. We find that ENT concentrations in the receiving waterway vary as a function of tidal stage and antecedent rainfall, but also site‐specific characteristics of the stormwater network that drains to the waterway. Tidal variables significantly explain measured ENT variance in the waterway, however, runoff drove higher ENT concentrations in the receiving waterway. Samples of floodwaters on roadways during both perigean spring tide events were limited, but all samples exceeded the threshold for safe public use of recreational waters. These results indicate that inundation of stormwater networks by tides could pose public health hazards in receiving water bodies and on roadways, which will likely be exacerbated in the future due to continued SLR. Plain Language Summary: Communities along the US Atlantic Coast have begun to experience the effects of sea‐level rise as stormwater drainage pipes, originally designed when sea levels were lower, are now routinely inundated at high tide. We do not know whether frequent inundation of stormwater drainage pipes affects coastal water quality, specifically the fecal bacteria levels of coastal waters. In this study, we collected daily measurements of Enterococcus spp. (ENT), the bacteria used by regulators to assess the safety of marine waters for swimmers and recreators, from a tidal creek over a 2‐month period. We also collected water samples from roadway floodwaters and the adjacent tidal creek during the highest high tides when the stormwater pipes drained during the outgoing tide. After data collection, we developed statistical models to relate the amount of ENT in the tidal creek to tide, rainfall, and stormwater infrastructure. When comparing rainfall and tide, we observed that rainfall caused greater bacterial contamination in the tidal creek than high tide flooding. However, we observed high ENT concentrations in roadway floodwaters and in the creek during the outgoing tide, leading us to conclude that everyday flooding of underground stormwater pipes at high tide could create hazardous water quality. Key Points: Daily observations of Enterococcus spp. concentrations in a coastal waterway were similar during and outside of perigean spring tidesTidal inundation of stormwater networks occurred daily, but rainfall runoff produced the greatest bacterial contamination in the waterwayHigh Enterococcus spp. concentrations were observed in roadway floodwaters and the receiving waterway during perigean spring tides [ABSTRACT FROM AUTHOR]

Highly anthropized areas as ports represent complex scenarios that require accurate monitoring plans aimed to address the environmental status. In this context, the activities of the EU Interreg Project "GEstione dei REflui per il MIglioramento delle Acque portuali (GEREMIA)" were focused on comparing sites differently affected by human presence, as the Port of Genoa and the natural area of the S'Ena Arrubia fishpond: a panel of analyses was carried out on Mugilidae fish sampled in these two areas, aimed to address trace metal accumulation in the liver, gills, and muscle, as well as cytochrome P450 (CYP450) induction in liver and biliary polycyclic aromatic hydrocarbon (PAH) metabolites, and histopathological alterations in the liver and gills. Chemical analyses in the liver, gills, and muscle of specimens collected in the port area showed an overall higher degree of trace metal contamination compared to the natural fishpond, and similar results were obtained in terms of CYP450 induction and biliary PAH metabolites, suggesting a higher exposure to organic compounds. In addition, histopathological analyses revealed a significant alteration and then a loss of functionality of liver and gill tissue in individuals from the port. Overall, this study describes the complex environmental pollution scenario in the Port of Genoa, confirming the importance of using multidisciplinary approaches and different types of analyses to address both the presence and the effects of contaminants in marine environments. [ABSTRACT FROM AUTHOR]

In this study, we examine the spatial correlation between China's regional digital financial development and its driving factors based on a network perspective and relational data. Based on the 2011-2020 digital financial inclusion index for 31 Chinese provinces (autonomous regions and municipalities directly under the central government), compiled by Peking University, and Pearson's correlation coefficient method and SNA method to analyze the data. Based on the quantitative analysis, Chinese provincial digital financial development shows a significant "center (eastern provinces) - edge (central and western provinces)-unbalanced spatial distribution pattern. The correlation relationship and spillover effect of interprovincial digital financial development are prominent. It is important to note that there is a low degree of spatial correlation, no pronounced hierarchical structure or redundancy in the spatial spillover network, and a good degree of robustness in the spatial spillover network. In China, digital financial development mainly occurs in the developed coastal provinces along the east coast, while the central and western provinces are on the periphery of this development. Eastern provinces serve as intermediaries and centers for digital financial development, attracting the inflow of factors and resources from the central and western regions. All 31 provinces are divided into four different types of blocks, each with a different status and role in the spatial spillover network. Each block has its own functions and comparative advantages. The short geographical distance between the provinces, the large gap in economic development and informatization levels, the similarity in financial literacy and the small income gap are all conducive to facilitating digital finance spillovers from the provinces and narrowing the gap in digital finance development between the provinces. The findings may have a positive impact on the ability of policymakers to promote the harmonious development of digital finance at the provincial level in China. [ABSTRACT FROM AUTHOR]

Tidal freshwater zones (TFZs) can significantly affect nutrient transport from watersheds to estuaries through biogeochemical cycling. Phytoplankton, pivotal in nutrient cycling, have been relatively understudied within TFZs. Employing accessory pigment analysis, this study assessed the contribution of diverse phytoplankton groups to chlorophyll a (chl a) biomass over an annual cycle under baseflow conditions. Spatial and temporal patterns in chl a concentrations and community structure as inferred from accessory pigment analysis were evaluated in relation to temperature, dissolved inorganic nitrogen (DIN), soluble reactive phosphorus (SRP), and DIN/SRP ratios. Downstream phytoplankton transport and seasonal succession within the TFZ, driven by nutrient levels and temperature, lead to variations in chl a concentration and community composition. Overall chl a levels were higher in the TFZ than in the upstream river and downstream estuary, with cyanobacteria prominently contributing to chl a biomass, especially in the lower TFZ sections. This study underscores the role of prolonged residence times and nutrient enrichment in TFZs, resulting in elevated chl a concentrations and shaping phytoplankton community composition, with implications for downstream estuaries. [ABSTRACT FROM AUTHOR]

The goal of the study was attempted to understand the impact of selected ports on the coastal and nearshore dynamics. Dwelling activities along the coastal zone were particularly high in the last two decades. Hence, ports constructed between 2000 and 2022 such as Mundra, Hazira, Karaikal, Krishnapatnam, Gangavaram, and Gopalpur were considered for the study. The land and shore dynamics were assessed prior and after their construction. The landward impact was identified by the changes in LULC, and the dynamics of coastal sediments were assessed from numerical model before and after the ports' construction. The highly impacted land and shore features were used in analytical hierarchy process (AHP) to assess the extent of their impact due to port construction. The extent of impacts was indicated as "criteria weight (CW)" expressed as percentage. Village-wise local sensitivity analysis (LSA) of the port environs due to port activities was also assessed with six parameters such as changes in LULC, cyclone, population, road network, cultural heritage site and shore stability based on their influence on the coast on case-by-case basis using AHP. The obtained influence of the impact of these parameters was used to determine the category of local sensitivity of the adjacent villages around the ports. For effective management planning, the LSA was classified into five classes, namely, very low, low, moderate, high, and very high. Villages categorized with different sensitivities can be attempted for suitable management plans and similar studies can be attempted for all villages impacted by port interventions. [ABSTRACT FROM AUTHOR]

Global route planning has garnered global scholarly attention as a crucial technology for ensuring the safe navigation of intelligent ships. The comprehensive influence of time-varying factors such as water depth, prohibited areas, navigational tracks, and traffic separation scheme (TSS) on ship navigation in coastal global route planning has not been fully considered in existing research, and the study of route planning method from the perspective of practical application is still needed. In this paper, a global route planning method based on human-like thinking for coastal sailing scenarios is proposed. Based on the historical route's information, and taking into full consideration those time-varying factors, an abnormal waypoint detection and correction method is proposed to make the planned route conform to relevant regulations of coastal navigation and the common practices of seafarers as much as possible, and better meet the coastal navigation needs of unmanned ships. Taking the global route planning of "ZHIFEI", China's first autonomous navigation container ship, as an example, the validity and reliability of the proposed method are verified. Experimental findings demonstrate the efficacy of the proposed method in global route planning for coastal navigation ships. The method offers a solid theoretical foundation and technical guidance for global route planning research of unmanned ship. [ABSTRACT FROM AUTHOR]

Rapid expansion of mariculture during past decades has raised substantial concerns about impacts on the coastal environment, notably eutrophication. This study focuses on one of the world's highest density mariculture sites, Sansha Bay, Fujian Province, China, featuring integrated multi-trophic aquaculture practices involving croaker, kelp and oyster, based on examination of nutrient distributions and releases. A two-endmembers-mixing model showed significant addition of dissolved inorganic nitrogen (DIN; 6.9 ± 4.1 μmol L-1) and phosphorus (DIP; 0.45 ± 0.29 μmol L-1) associated with mariculture activities in spring 2020. A mass balance model estimated an annual release of N and P from cage fish farming systems fed with mixed trash fish feed and formulated feed of (2.42 ± 0.15)×104 tons and (5.33 ± 0.37)×103 tons, respectively. Of the total feed input, 52.8 ± 4.7 % of DIN and 33.0 ± 3.7 % of DIP were released into seawater, values much higher than the riverine input and exchange with offshore coastal waters. A co-culture strategy involving kelp and oyster production in 2020 removed (1.08 ± 0.01)×103 tons of N and (1.56 ± 0.08) ×102 tons of P, respectively. Therefore, adjusting feed strategies and improving feed conversion rates could alleviate eutrophication caused by mariculture expansion in this ecosystem. [ABSTRACT FROM AUTHOR]

Bio‐optical properties of marine phytoplankton retrieved through satellite remote sensing are used to estimate ocean productivity and carbon cycling. Daily activity of phytoplankton is attuned to the predictable light fluctuations of the diel cycle. Field and laboratory studies have documented diel changes in phytoplankton growth, division, and respiration, carbon and pigment content, cell size, photosynthetic efficiency and rate, and DNA replication and transcription. Many of these physiological changes can alter cellular optical properties and contribute to diel variations in bulk absorption and scattering properties. Consequently, understanding phytoplankton contributions to diel optical cycles is essential for improving algorithms that convert remote sensing data to biological rates and stocks. Here, we describe time‐resolved cellular, photophysiological, and bio‐optical properties for three cultured phytoplankton ranging in cell size from ~ 1 to 6 μm: Ostreococcus lucimarinus, Synechococcus (WH8102), and Thalassiosira pseudonana, all of which can significantly contribute to phytoplankton abundance and/or biomass in the open and coastal ocean. This work is the first to characterize complete diel cycles in absorption and attenuation for O. lucimarinus and backscattering for all these species. Results show that the percent increase from the minimum to maximum values over the diel cycle ranged between ~ 24–121%, ~ 31–235%, and ~ 25–198% for particulate absorption, attenuation, and backscattering, respectively. Diel changes in bio‐optical properties also differed in both timing and magnitude across phytoplankton species, demonstrating the importance of contextualizing remote sensing observations with phytoplankton community composition. [ABSTRACT FROM AUTHOR]

The existence of coastal ecosystems depends on their ability to gain sediment and keep pace with sea level rise. Similar to other coastal areas, Northeast Florida (United States) is experiencing rapid population growth, climate change, and shifting wetland communities. Rising seas and more severe storms, coupled with the intensification of human activities, can modify the biophysical environment, thereby increasing coastal exposure to storm-induced erosion and inundation. Using the Guana Tolomato Matanzas National Estuarine Research Reserve as a case study, we analyzed the distribution of coastal protection services-expressly, wave attenuation and sediment control-provided by estuarine habitats inside a dynamic Intracoastal waterway. We explored six coastal variables that contribute to coastal flooding and erosion-(a) relief, (b) geomorphology, (c) estuarine habitats, (d) wind exposure, (e) boat wake energy, and (f) storm surge potential-to assess physical exposure to coastal hazards. The highest levels of coastal exposure were found in the north and south sections of the Reserve (9% and 14%, respectively) compared to only 4% in the central, with exposure in the south driven by low wetland elevation, high surge potential, and shorelines composed of less stable sandy and muddy substrate. The most vulnerable areas of the central Reserve and main channel of the Intracoastal waterway were exposed to boat wakes from larger vessels frequently traveling at medium speeds (10-20 knots) and had shoreline segments oriented towards the prevailing winds (north-northeast). To guide management for the recently expanded Reserve into vulnerable areas near the City of Saint Augustine, we evaluated six sites of concern where the current distribution of estuarine habitats (mangroves, salt marshes, and oyster beds) likely play the greatest role in natural protection. Spatially explicit outputs also identified potential elevation maintenance strategies such as living shorelines, landform modification, and mangrove establishment for providing coastal risk-reduction and other ecosystem-service co-benefits. Salt marshes and mangroves in two sites of the central section (N-312 and S-312) were found to protect more than a one-quarter of their cross-shore length (27% and 73%, respectively) from transitioning to the highest exposure category. Proposed interventions for mangrove establishment and living shorelines could help maintain elevation in these sites of concern. This work sets the stage for additional research, education, and outreach about where mangroves, salt marshes, and oyster beds are most likely to reduce risk to wetland communities in the region. [ABSTRACT FROM AUTHOR]

Nitrogen dioxide (NO2) and formaldehyde (HCHO) play vital roles in atmospheric photochemical processes. Their tropospheric vertical column density (TVCD) distributions have been monitored by satellite instruments. Evaluation of these observations is essential for applying these observations to study photochemistry. Assessing satellite products using observations at rural sites, where local emissions are minimal, is particularly useful due in part to the spatial homogeneity of trace gases. In this study, we evaluate OMI and TROPOMI NO2 and HCHO TVCDs using multi‐axis differential optical absorption spectroscopy (MAX‐DOAS) measurements at a rural site in the east coast of the Shandong province, China in spring 2018 during the Ozone Photochemistry and Export from China Experiment (OPECE) measurement campaign. On days not affected by local burning, we found generally good agreement of NO2 data after using consistent a priori profiles in satellite and MAX‐DOAS retrievals and accounting for low biases in scattering weights in one of the OMI products. In comparison, satellite HCHO products exhibited weaker correlations with MAX‐DOAS data, in contrast to satellite NO2 products. However, TROPOMI HCHO products showed significantly better agreement with MAX‐DOAS measurements compared to OMI data. Furthermore, case studies of the vertical profiles measured by MAX‐DOAS on burning days revealed large enhancements of nitrous acid (HONO), NO2, and HCHO in the upper boundary layer, accompanied with considerable variability, particularly in HONO enhancements. Plain Language Summary: We compared satellite NO2 and HCHO tropospheric vertical columns (TVCDs), that is, the integrated column concentrations from the surface to the top of the troposphere, from OMI and TROPOMI instruments with ground‐based MAX‐DOAS measurements in spring 2018 at a rural coastal site in China. Our results on non‐burning days indicate good agreement between satellite products and MAX‐DOAS measurements for NO2 TVCDs, albeit with some biases in one of the products. Potential factors contributing to the biases in that satellite product are investigated. Satellite HCHO products, however, did not compare as well with MAX‐DOAS data as satellite NO2 products, although TROPOMI HCHO products showed better agreement with MAX‐DOAS data than OMI HCHO products. We further analyzed MAX‐DOAS observations of HONO and HCHO on days with nearby agricultural burning activities. We found that HONO, NO2, and HCHO can be significantly enhanced by burning, but the increase due to nearby fires, especially for HONO, is highly variable. Key Points: Satellite NO2 products are in much better agreement with MAX‐DOAS measurements than HCHO productsTROPOMI HCHO products have a significantly lower RMSE and better correlation with MAX‐DOAS data than OMI HCHO productsAgricultural burning can significantly enhance HONO, NO2, and HCHO in the upper boundary layer, but enhancements due to fires, particularly of HONO, are highly variable [ABSTRACT FROM AUTHOR]

As critical transition zones between the land and the sea, estuaries are not only hotspots of hydrogeochemical and microbial processes/reactions, but also play a vital role in processing and transferring terrestrial fluxes of metals and nutrients to the sea. This study focused on three estuaries in the Gulf of Bothnia. All of them experience frequent inputs of acidic and Mn/metal-rich creek waters due to flushing of acid sulfate soils that are widespread in the creekś catchments. Analyzing existing long-term water chemistry data revealed a strong seasonal variation of Mn loads, with the highest values in spring (after snow melt) and autumn (after heavy rains). We sampled surface waters, suspended particulate matter (SPM), and sediments from the estuarine mixing zones and determined the loads and solid-phase speciation of Mn as well as the composition and metabolic potentials of microbial communities. The results showed that the removal, cycling, and lateral transport of Mn were governed by similar phases and processes in the three estuaries. Manganese X-ray absorption spectroscopy data of the SPM suggested that the removal of Mn was regulated by silicates (e.g., biotite), organically complexed Mn(II), and MnOx (dominated by groutite and phyllomanganates). While the fractional amounts of silicate-bound Mn(II) were overall low and constant throughout the estuaries, MnOx was strongly correlated with the Mn loadings of the SPM and thus the main vector for the removal of Mn in the central and outer parts of the estuaries, along with organically complexed Mn(II). Down estuary, both the fractional amounts and average Mn oxidation state of the MnOx phases increased with (i) the total Mn loads on the SPM samples and (ii) the relative abundances of several potential Mn-oxidizing bacteria (Flavobacterium, Caulobacter, Mycobacterium, and Pedobacter) in the surface waters. These features collectively suggested that the oxidation of Mn, probably mediated by the potential Mn-oxidizing microorganisms, became more extensive and complete towards the central and outer parts of the estuaries. At two sites in the central parts of one estuary, abundant phyllomanganates occurred in the surface sediments, but were converted to surface-sorbed Mn(II) phases at deeper layers (>3–4 cm). The occurrence of phyllomanganates may have suppressed the reduction of sulfate in the surface sediments, pushing down the methane sulfate transition zone that is typically shallow in estuarine sediments. At the outermost site in the estuary, deposited MnOx were reduced immediately at the water–sediment interface and converted most likely to Mn carbonate. The mobile Mn species produced by the Mn reduction processes (e.g., aqueous Mn(II) and ligand complexed Mn(III)) could partly diffuse into the overlying waters and, together with the estuarine Mn loads carried by the surface waters, transfer large amounts of reactive Mn into open coastal areas and subsequently contribute to Mn shuttling and inter-linked biogeochemical processes over the seafloor. Given the widespread occurrence of acid sulfate soils and other sulfidic geological materials on many coastal plains worldwide, the identified Mn attenuation and transport mechanisms are relevant for many estuaries globally. [ABSTRACT FROM AUTHOR]

The freshwater phase of the first seaward migration of juvenile Atlantic salmon (Salmo salar) is relatively well understood when compared with our understanding of the marine phase of their migration. In 2021, 1008 wild and 60 ranched Atlantic salmon smolts were tagged with acoustic transmitters in 12 rivers in England, Scotland, Northern Ireland and Ireland. Large marine receiver arrays were deployed in the Irish Sea at two locations: at the transition of the Irish Sea into the North Atlantic between Ireland and Scotland, and between southern Scotland and Northern Ireland, to examine the early phase of the marine migration of Atlantic salmon smolts. After leaving their natal rivers' post‐smolt migration through the Irish Sea was rapid with minimum speeds ranging from 14.03 to 38.56 km.day−1 for Atlantic salmon smolts that entered the Irish Sea directly from their natal river, to 9.69–39.94 km.day−1 for Atlantic salmon smolts that entered the Irish Sea directly from their natal estuary. Population minimum migration success through the study area was strongly correlated with the distance of travel, populations further away from the point of entry to the open North Atlantic exhibited lower migration success. Post‐smolts from different populations experienced different water temperatures on entering the North Atlantic. This was largely driven by the timing of their migration and may have significant consequences for feeding and ultimately survivorship. The influence of water currents on post‐smolt movement was investigated using data from previously constructed numerical hydrodynamic models. Modeled water current data in the northern Irish Sea showed that post‐smolts had a strong preference for migrating when the current direction was at around 283° (west‐north‐west) but did not migrate when exposed to strong currents in other directions. This is the most favorable direction for onward passage from the Irish Sea to the continental shelf edge current, a known accumulation point for migrating post‐smolts. These results strongly indicate that post‐smolts migrating through the coastal marine environment are: (1) not simply migrating by current following (2) engage in active directional swimming (3) have an intrinsic sense of their migration direction and (4) can use cues other than water current direction to orientate during this part of their migration. [ABSTRACT FROM AUTHOR]

The Port State Control system aims to ensure that all ships are subject to regular inspections, with particular attention to the ships of insufficient quality. To this end, during the inspection, priority is given to ships that are considered risky. Thetis database is an information system that contributes to the implementation of the Port State Control within the EU (European Unit). It contains data on inspections performed in the EU ports and the Paris Memorandum area. The Paris Memorandum has 27 member states and covers the waters of European coastal states and the North Atlantic basin from North America to Europe. The main goal of the Paris MoU (Memorandum of Understanding) is to eliminate substandard ships through a harmonized Port State Control system. Namely, inspections should ensure that ships meet international safety standards, are safe for the environment, and provide adequate living and working conditions for workers. The primary responsibility for ensuring these standards rests with the ship owner/shipper while the responsibility for ensuring such compliance rests with the flag state. The aim of this analysis is to determine the number of inspections performed in the ports of the Republic of Croatia and the Republic of Italy, to identify the cause of ship detentions and the most common deficiencies of offshore supply vessels, MODU (Mobile Offshore Drilling Units) and FPSO (Floating Production Storage and Offloading) Units. In the observed period, the impact of the crisis caused by the COVID-19 pandemic was significant, resulting in the decline in the numbers of inspections performed in 2020 and 2021. In 2022, the number of inspections increased, but it still has not reached its pre-pandemic level. During the period that was the subject of research, port state inspections in the Republic of Croatia and the Republic of Italy revealed 241 deficiencies. Five areas with the largest number of deficiencies are: Certificate & Documentation, Safety of Navigation, Fire Safety, ISM, and Lifesaving appliances, which follow the trend of the lack in the areas of the Paris Memorandum. The greatest increase in deficiencies was recorded in the areas of Labor Conditions-Health protection, Certificate & Documents (Crew Certificate, Documents), Emergency System and Fire safety area, which led to an increase in the number of offshore supply ships retention during the first half of 2022. [ABSTRACT FROM AUTHOR]

Hurricanes are one of the most common natural events that disturb estuarine and coastal wetlands along the Gulf of Mexico. The episodic and energetic events of hurricanes modify wetland hydrodynamics, sedimentation, and vegetation structure, which can impact the connectivity of coastal deltaic floodplains in processing riverine nutrients. Hurricane effects on benthic nitrogen dynamics and their fluxes during ecosystem recovery following an event were investigated at three experimental sites with distinct sediment organic matter (SOM) concentrations (lower-, intermediate-, and higher-SOM) in Wax Lake Delta (WLD), Louisiana. Intact sediment cores were incubated with 15NO3− enrichment prior to, 1 month, 2 years, and 3 years post Hurricane Barry. The disturbance of Hurricane Barry on benthic nitrogen dynamics was most significant at the higher-SOM site, where SOM concentrations significantly decreased together with a 50% reduction in rates of direct denitrification, coupled nitrification-denitrification, and dissimilatory nitrate reduction to ammonium (DNRA). Shifts in SOM and benthic nitrogen dynamics as result of hurricane sedimentation followed the linear function between increased denitrification (or NO3− fluxes) with greater SOM concentrations previously established by sampling along SOM gradients in WLD. The estimated NO3− removal capacity decreased by 8.5% (76 Mg N year−1) compared to pre-hurricane conditions due to lower SOM concentrations associated with mineral sedimentation at the most disturbed site. The disturbed site had not recovered to pre-hurricane conditions in terms of SOM concentrations and benthic nitrogen dynamics three years after Hurricane Barry. NO3− removal capacity of an active delta such as WLD is a combination of SOM increase from ecological succession and SOM decrease associated with events that stimulate mineral deposition. Frequency of high energy events such as floods and storms along with wetland feedback in soil organic development and delta expansion will influence NO3− removal capacity. [ABSTRACT FROM AUTHOR]

The results of using an unmanned aerial vehicle (UAV) to study the processes of gravitational wave breaking are presented. The experiments are carried out in the coastal zone of the western Crimea (the area of Sevastopol) in the range of wind speeds from 5.5 to 9.5 m/s. The determination of the geometric dimensions of breaking and their speeds is carried out according to video recordings of the sea surface obtained from the UAV. It is shown that the spatial resolution of the transformed image plays a key role in separating the active phase of breaking and residual foam. Errors occur in determining the kinematic properties of the breaking with a rough spatial resolution. The proportion of the sea surface covered with foam of breaking waves, the ratio of the maximum length of the spume to the length of the breaking wave, and the distribution of the total breaking length in the intervals of movement speeds per surface unit (obtained from UAVs with a spatial resolution better than 0.5m) are in agreement with results of other authors. Data analysis shows that the use of UAVs makes it possible to study the statistical characteristics and kinematics of wind wave breaking. At the same time, it is necessary to take into account the effect of spatial resolution in the video frame, which can lead to the distortion or omission of measurement data at values comparable to or exceeding the breaking scale. [ABSTRACT FROM AUTHOR]

The offshore transport of Greenland coastal waters influenced by freshwater input from ice sheet melting during summer plays an important role in ocean circulation and biological processes in the Labrador Sea. Many previous studies over the last decade have investigated shelfbreak transport processes in the region, primarily using ocean model simulations. Here, we use 27 years of surface geostrophic velocity observations from satellite altimetry, modified to include Ekman dynamics based on atmospheric reanalysis, and virtual particle releases to investigate seasonal and interannual variability in transport of coastal water in the Labrador Sea. Two sets of tracking experiments were pursued, one using geostrophic velocities only, and another using total velocities including the wind effect. Our analysis revealed substantial seasonal variability, even when only geostrophic velocities were considered. Water from coastal southwest Greenland is generally transported northward into Baffin Bay, although westward transport off the west Greenland shelf increases in fall and winter due to winds. Westward offshore transport is increased for water from southeast Greenland so that, in some years, water originating near the east Greenland coast during summer can be transported into the central Labrador Sea and the convection region. When wind forcing is considered, long-term trends suggest decreasing transport of Greenland coastal water during the melting season toward Baffin Bay, and increasing transport into the interior of the Labrador Sea for water originating from southeast Greenland during summer, where it could potentially influence water column stability. Future studies using higher-resolution velocity observations are needed to capture the role of submesoscale variability in transport pathways in the Labrador Sea. [ABSTRACT FROM AUTHOR]

Ocean acoustic tomography (OAT) deploys most moored stations on the periphery of the tomographic region to sense the solenoidal current field. Moving vehicle tomography (MVT), an advancement of OAT, not only samples the region from various angles for improving the resolution of mapped currents but also acquires information about the irrotational flow due to the sampling points inside the region. To reconstruct a complete two-dimensional current field, the spatial modes derived from the open-boundary modal analysis (OMA) are preferable to the conventional truncated Fourier series since the OMA technique describes the solenoidal and irrotational flows efficiently in which all modes satisfy the coastline and open boundary conditions. Comparisons of the reconstructions are presented using three different representations of currents. The first two representations explain only the solenoidal flow: the truncated Fourier series and the OMA Dirichlet modes. The third representation, accounting for the solenoidal and irrotational flows, uses all the OMA modes. For reconstructing the solenoidal flow, the OMA representation with the Dirichlet modes performs better than the Fourier series. A large difference appears near the bay mouth, where the OMA-Dirichlet reconstruction shows a better fit to the uniform currents. However, considerable uncertainty exists outside the bay mouth where the irrotational currents dominate. This can be improved by the third representation with the inclusion of the Neumann and boundary modes. The reconstruction results using field data were validated against the acoustic Doppler current profiler (ADCP) measurements. Additionally, incorporating constraints from ADCP measurements enhances the accuracy of the reconstruction. Significance Statement: This study contributes toward improving our understanding of accurately measuring oceanic circulation patterns over large areas without relying solely upon stationary sensors or satellite imagery. The study combines multiple sources, such as shipboard ADCP and tomographic techniques, to obtain a complete picture of what is happening beneath surface waters across entire regions under investigation. It has important implications for fields such as climate science, marine biology, and fisheries management, where accurate knowledge of the movement and distribution of water masses is crucial for predicting future trends and making informed decisions. [ABSTRACT FROM AUTHOR]

Ship trajectory data can be used in most marine-related research, and most ship trajectory data come from AIS. The large number of ships and the short reporting period of AIS have resulted in a huge amount of ship trajectory data, which has caused a certain amount of pressure on the relevant research. This paper proposes a direction-preserved vessel trajectory compression method based on Open Window, which can effectively retain the direction change feature points while ensuring the position error. In addition, the method can work in both offline and online modes. Also, the velocity threshold and low-speed redundancy points problems are considered. In order to verify the effect of the proposed method and the adaptability of the method to different feature data, a parallel experiment was performed on port water and coastal water datasets. The results show that our method can compress vessel trajectories while retaining the feature points. Meanwhile, by comparing it with the compression method that is based on distance thresholds, the vessel trajectory compress time is drastically reduced by up to 87.3% in the port water data. The research in this paper provides a new method through which to compress vessel trajectories for research in marine-related fields on vessel trajectory. [ABSTRACT FROM AUTHOR]

Wetlands, situated at the vital intersection of terrestrial and aquatic ecosystems, are pivotal in preserving global biodiversity and maintaining environmental equilibrium. The escalating trend of global urbanization necessitates the utilization of high-resolution satellite imagery for accurate wetland delineation, which is essential for establishing efficacious conservation strategies. This study focuses on the wetlands of Macau, characterized by distinctive coastal and urban features. A noteworthy enhancement in this study is the integration of the Coordinate Attention mechanism with the RegNet model, forming the CA-RegNet. This combined model demonstrates superior performance, outdoing previous Macau wetlands segmentation studies that used ResNet, evidenced by an approximate rise of 2.7% in overall accuracy (OA), 4.0% in the Kappa coefficient, 1.9% in the mAcc, and 0.5% in the mIoU. Visual evaluations of the segmentation results reinforce the competence of the CA-RegNet model in precisely demarcating coastal wetlands and Saiwan Lake, thereby overcoming the former constraints of ResNet and underscoring the robustness and innovation of this study. [ABSTRACT FROM AUTHOR]

Humans have intensively sailed the Mediterranean and European Atlantic waters throughout history, from the upper Paleolithic until today and centuries of human seafaring have established complex coastal and cross-seas navigation networks. Historical literature revealed three major long-lasting maritime routes (eastern, western, northern) with four commencing locations (Alexandria, Venice, Genoa, Gibraltar) and a fourth route (circum-Italian) that connected between them. Due to oceangoing and technological constraints, most voyages were coastal, lasted weeks to months, with extended resting periods, allowing the development of fouling organisms on ship hulls. One of the abiding travellers in maritime routes is the colonial ascidian Botryllus schlosseri already known since the eighteenth century in European and Mediterranean ports. This species, was almost certainly one of the common hull fouling travellers in all trade routes for centuries. Employing COI haplotypes (1008 samples) and microsatellite alleles (995 samples) on colonies sampled from 64 pan-European sites, present-day Botryllus populations in the Mediterranean Sea/European Atlantic revealed significant segregation between all four maritime routes with a conspicuous partition of the northern route. These results reveal that past anthropogenic transports of sedentary marine species throughout millennia long seafaring have left their footprint on contemporary seascape genetics of marine organisms. [ABSTRACT FROM AUTHOR]

Earth Observation (EO) data, such as Landsat 7 (L7) and Sentinel 2 (S2) imagery, are often used to monitor the state of natural resources all over the world. However, this type of data tends to suffer from high cloud cover percentages during rainfall/snow seasons. This has led researchers to focus on developing algorithms for filling gaps in optical satellite imagery. The present work proposes two modifications to an existing gap-filling approach known as the Direct Sampling (DS) method. These modifications refer to ensuring the algorithm starts filling unknown pixels (UPs) that have a specified minimum number of known neighbors (Nx) and to reducing the search area to pixels that share similar reflectance as the Nx of the selected UP. Experiments were performed on images acquired from coastal water bodies in France. The validation of the modified gap-filling approach was performed by imposing artificial gaps on originally gap-free images and comparing the simulated images with the real ones. Results indicate that satisfactory performance can be achieved for most spectral bands. Moreover, it appears that the bi-layer (BL) version of the algorithm tends to outperform the uni-layer (UL) version in terms of overall accuracy. For instance, in the case of B04 of an L7 image with a cloud percentage of 27.26%, accuracy values for UL and BL simulations are, respectively, 64.05 and 79.61%. Furthermore, it has been confirmed that the introduced modifications have indeed helped in improving the overall accuracy and in reducing the processing time. As a matter of fact, the implementation of a conditional filling path (minNx = 4) and a targeted search (n2 = 200) when filling cloud gaps in L7 imagery has contributed to an average increase in accuracy of around 35.06% and an average gain in processing time by around 78.18%, respectively. [ABSTRACT FROM AUTHOR]

An unmanned surface vehicle (USV; Wave Glider) was deployed to study the coastal soundscape in shallow (less than 30 m) coastal waters off the coast of Cape Canaveral, FL, in July 2020 and January 2022. These surveys documented temporal and seasonal trends in biological sounds across a variety of habitats within an 812-km2 survey area, including sand shoals, sand-mud plains, and natural hardbottom. Among a broader diversity of identifiable and unidentifiable fish choruses recorded during the survey, a distinct and previously unidentified fish chorus was recorded; corroborating evidence suggests it and other sounds with similar spectral properties may be produced by Atlantic midshipman. Putative Atlantic midshipman sounds included an agnostic grunt and a seasonal chorus of persistent hums that peaked 3 h after sunset in the summer survey. While Atlantic midshipman have been demonstrated to have well-developed sonic muscles on their swim bladder, their acoustic behavior has not been previously described. Our use of a mobile passive acoustic platform combined with bottom sampling of fish communities highlights an important opportunity to identify previously undocumented biological sound sources in coastal habitats. [ABSTRACT FROM AUTHOR]

In recent years, the increasing volume and complexity of ship traffic has raised the probability of collision accidents in ports, waterways, and coastal waters. Due to the relative rarity of collision accidents, near misses have been used in the research to study the collision risk in the relevant water areas. However, the factor of near miss identification is usually limited to the relative distance between ships, and the instantaneous quantification and geographical distribution of collision risk is not paid enough attention. Therefore, this article proposed a domain-based regional collision risk model that can quantify the collision risk by detecting near miss scenarios. The proposed model is capable of quantifying the collision risk in the water area instantaneously and periodically and can be used to depict the geographical distribution of collision risks in combination with a grid method and the spatial interpolation technique. To validate the proposed model, some experimental case studies were carried out using automatic identification system (AIS) data from the Bohai Strait. The results show the capability and advantage of the proposed model in regional collision risk identification and visualization, which is helpful for maritime surveillance when monitoring and organizing ship traffic and may therefore contribute to the improvement of maritime safety. [ABSTRACT FROM AUTHOR]

The transport mechanisms of floating marine debris in coastal zones remain poorly understood, primarily due to the complex geometry and influence of coastal processes which pose difficulties in incorporating them into Lagrangian numerical models at coastal scales. The numerical model presented in this study addresses these challenges using nested grids of varying hydrodynamic resolutions (2.5 km, 350 m, and 70 m). The model couples Eulerian hydrodynamic data with a Lagrangian particle solver to accurately simulate the motion of plastic particles in coastal regions. A Lagrangian validation of the model was conducted using drifter data to assess the model’s skill and confidence in simulation predictions. The results demonstrated high skill and stability in 72-hour forecast horizons and high skill score values close to the shoreline. Additionally, a beaching sensitivity analysis was performed to determine particle beaching parameterisations suitable for coastal zones. This analysis demonstrated that the real-time distance of particles to the shore during simulations was the most accurate method for detecting the land-water boundary at coastal scales, accurately representing residence times and spatiotemporal beaching patterns. Simulations were conducted using nested grids and a single coarse grid, both using the same plastic input from river outflows in a pilot test at the Barcelona coastline with a complex morphology due to coastal structures, two major river mouths, and a large harbour. The simulations revealed marked differences in beaching amounts and residence times. Both simulations exhibited high levels of beaching, with the nested grid simulation registering 91.5 % beaching and the low-resolution grid simulation showing 95.8 % beaching, surpassing other studies conducted at larger scales. Beaching amounts exhibited high levels of variability within demarcated areas between simulations, with the highest flux observed near the Llobregat River mouth release point. The inner port area showed that particles have 18 times longer residence times when using high-resolution data, demonstrating the model’s ability to solve complex coastal geometrical structures. By using nested grids, the model can resolve coastal processes with high-resolution hydrodynamic data and accurately simulate potential accumulation zones and litter hot-spots at coastal scales. [ABSTRACT FROM AUTHOR]

High- and medium-resolution satellite optical imagery show that submesoscale cyclonic eddies (SCEs) trap coastal waters and induce their rapid cross-shelf transport. Due to the presence of a rigid boundary, the convergence is observed in the coastal part of SCEs. It causes accumulation of suspended matter, which spins inward in a spiral motion toward the SCE core. Small SCEs with a radius of 1–10 km transport waters with local anomalies in the concentration of chlorophyll, total suspended matter and temperature to a distance of up to 150 km and are observed for more than 10 days. Lagrangian calculations based on realistic NEMO numerical model are used to estimate the fate of the coastal waters in such SCEs. The eddy entrains the largest number of particles during its separation from the coast when its vorticity reaches the maximum. Then, the SCE weakens, which is accompanied by the flattening of initially risen isopycnals and deepening of the trapped coastal waters. The described mechanism shows that coastal SCEs may cause intense short-period cross-shelf transport of the biological and chemical characteristics, and is another process affecting the functioning of the marine ecosystems. [ABSTRACT FROM AUTHOR]

In this study, an ensemble of numerical simulations with a state-of-the-art hydrodynamic model for coastal applications is used to characterize, for the first time, the expected mid-21st-century changes in circulation and associated sea-level height inside the Venice lagoon induced by projected Mediterranean sea level rise and atmospheric circulation changes over the Adriatic Sea under the RCP8.5 emission scenario. Our results show that water transports through the three inlets connecting the Venice lagoon to the open sea are expected to change significantly, with consequent significant persistent alterations of the circulation and sea-level height inside the lagoon. The projected water mass redistributions motivate further studies on the implications of climate change for the lagoon environment. [ABSTRACT FROM AUTHOR]

Shallow Water Acoustic Vector Sensor Array AutoNomous System (SVAAN) is a passive acoustic monitoring system using vector sensors. Acoustic vector sensors measure acoustic pressure and particle velocity, and an array of such sensors are very useful in underwater source localization. SVAAN is thus developed for surveillance applications in coastal waters and designed for a 100-m depth rating. The main objective of this work is to present SVAAN that is developed as a sea bed mounted system, consisting of two vector sensors and four hydrophones. In addition, an inertial sensor has been included to measure the system orientation when deployed. This was deployed as a bottom mounted unit in the shallow waters of South-West Bay of Bengal to measure the noise from boats/ships and localize the source. The acoustic data are analyzed, Direction of Arrival is estimated using Multiple Signal Classification for source localization, and the performance of SVAAN is studied. In addition to that, the tracking of boat noise has been estimated from the experiment data. Results and further enhancement of the system are discussed. [ABSTRACT FROM AUTHOR]

Coastal oceans, the transition zones between terrestrial and oceanic systems, are susceptible to anthropogenic mercury (Hg) inputs and are regarded as critical dynamic interfaces of the global Hg cycle. However, the extent to which coastal oceans are accountable for sequestering Hg remains largely unknown owing to the lack of data on high‐resolution Hg accumulation in marine sediments. Synthesizing the results of this study (eight cores and 212 surface sediments) and the literature (three cores and 149 surface sediments), we provide a quantitative evaluation of the biogeochemical cycle of sedimentary Hg in the East China Marginal Seas (ECMS), including the response of the coastal marine sediments to anthropogenic disturbance as well as both human‐derived and natural Hg burial fluxes. We find a linear increase in Hg accumulation since the 1950s (2.0 ± 2.5% yr−1) and a decline in Hg accumulation between 2010 and 2016. Modern burial fluxes of total and anthropogenic Hg in the ECMS (covering ∼4.8 × 105 km2 of sea surface) were estimated to be 89.1 ± 48.3 and 35.9 ± 33.1 Mg yr−1, respectively. Using a compilation of 688 surface sediments and 131 sediment cores (819 samples in total) distributed globally in coastal oceans, we estimate that approximately 1,590 (range: 1,190–2,760) Mg yr−1 (Method 1) and 540 (range: 310–960) Mg yr−1 (Method 2) Hg are accumulated in coastal ocean regions. Our findings suggest that coastal oceans are likely the largest global marine sinks for Hg and play a dominant role in regulating the oceanic Hg cycle and budgets. Plain Language Summary: The mercury (Hg) burial in the Eastern China Marginal Seas (ECMS) is a dynamic component of the global Hg cycle because it receives high delivery rates of Hg fluxes from the Chinese rivers, atmospheric deposition, and via other pathways, yet our understanding of accumulation and quantity of anthropogenic Hg stored in the ECMS remains poorly constrained. Modern Hg accumulation rate in the ECMS based on surface sediments and high‐resolution cores from muddy zones reveals that ∼40% of the contemporary Hg buried and stored in the ECMS was of anthropogenic origin. The temporal variation in sedimentary Hg accumulation over the past 120 years could be explained by changes in Chinese energy consumption, atmospheric Hg emission, and sediment fluxes associated with river damming. We directly quantified the contribution of coastal oceans to the burial of marine Hg in the ocean using two distinct approaches, including assessing Hg accumulation rates from sediment core data, as well as determining Hg content in marine sediments and sediment delivery rates. We conclude that due to high rates of terrestrial sediment delivery and increased levels of anthropogenic Hg, the coastal oceans exhibit high Hg accumulation rates on average and provide a large sink for global anthropogenic Hg burial. Key Points: Accumulation rates of Hg in the East China Marginal Seas and global coastal oceans are directly constrained using marine sediment dataAnthropogenic Hg burial accounts for ∼40% of the Hg stored in modern sediments of the East China Marginal SeasHg burial in the sediments of coastal oceans contributes to ∼80% (Method 1) and ∼60% (Method 2) of the total annual marine Hg burial globally [ABSTRACT FROM AUTHOR]

The LAPAN-A3 is the third microsatellite generation developed by the Research Center for Satellite Technology. The satellite can be used for land classification, agriculture monitoring, drought monitoring, and land use change. This study aims to classify land use and land cover in the research area. The main image used is LAPAN-A3; the compared images are Landsat-8 and Sentinel-2. Three images were taken on the same day and selected on cloud-free terms. The classification process starts with determining the region of interest (ROI) and the class. The classification is divided into six classes: water, forests, rice fields, settlements, open land, and coastal areas. The classification technique uses supervised learning with the maximum likelihood method. This study used Landsat 8 and Sentinel-2 data to compare the results obtained from LAPAN-A3. The accuracy test results for the LAPAN-A3 and Landsat-8 are 84.7042% and 0.783, respectively. While the accuracy test of LAPAN-A3 and Sentinel-2 is 72.2313%, the kappa value is 0.6394. The classification of two comparisons is quite accurate, with an accuracy of more than 70%. The LA3 classification successfully identifies water and coastal areas. The producer and accuracy is substantiated by comparing the results with both Landsat-8 and Sentinel-2 satellite data, which exhibit an accuracy rate exceeding 85%. Finally, LAPAN-A3 has great potential for classifying land use and land cover when compared to Landsat 8 and Sentinel-2 images, but future research should increase the number of datasets and vary the research area to improve the results. [ABSTRACT FROM AUTHOR]

Background: Anchialine environments, in which oceanic water mixes with freshwater in coastal aquifers, are characterised by stratified water columns with complex physicochemical profiles. These environments, also known as subterranean estuaries, support an abundance of endemic macro and microorganisms. There is now growing interest in characterising the metabolisms of anchialine microbial communities, which is essential for understanding how complex ecosystems are supported in extreme environments, and assessing their vulnerability to environmental change. However, the diversity of metabolic strategies that are utilised in anchialine ecosystems remains poorly understood. Results: Here, we employ shotgun metagenomics to elucidate the key microorganisms and their dominant metabolisms along a physicochemical profile in Bundera Sinkhole, the only known continental subterranean estuary in the Southern Hemisphere. Genome-resolved metagenomics suggests that the communities are largely represented by novel taxonomic lineages, with 75% of metagenome-assembled genomes assigned to entirely new or uncharacterised families. These diverse and novel taxa displayed depth-dependent metabolisms, reflecting distinct phases along dissolved oxygen and salinity gradients. In particular, the communities appear to drive nutrient feedback loops involving nitrification, nitrate ammonification, and sulphate cycling. Genomic analysis of the most highly abundant members in this system suggests that an important source of chemotrophic energy is generated via the metabolic coupling of nitrogen and sulphur cycling. Conclusion: These findings substantially contribute to our understanding of the novel and specialised microbial communities in anchialine ecosystems, and highlight key chemosynthetic pathways that appear to be important in these energy-limited environments. Such knowledge is essential for the conservation of anchialine ecosystems, and sheds light on adaptive processes in extreme environments. 8p_44mfK8oMcThCGxAovzM Video Abstract [ABSTRACT FROM AUTHOR]

The family Syngnathidae (seahorses, sea dragons and pipefishes) is a fascinating group. Species are mostly distributed in marine coastal waters, but about 30 species inhabit Indo-Pacific tropical island rivers. There are currently six freshwater genera of Nerophinae (trunk-brooders): Belonichthys , Coelonotus , Doryichthys , Lophocampus , Microphis and Oostethus. Unlike other Syngnathidae, freshwater pipefish have been little studied; the taxonomy of Nerophinae is unclear and only based on morphomeristic data. The purpose of our study is to undertake a revision of this group based on an integrative taxonomy approach. By combining molecular data from four mitochondrial markers (5415 bp), morphomeristic data with a character mapping study and ecological data, we now recognize a single genus as valid, Microphis , as opposed to the six previously accepted. Our results also reveal one new candidate species, Microphis nicoleae sp. nov. , and the resurrection of two others: Microphis torrentius and Microphis vaillantii. This study shows the relevance of integrative taxonomy for higher taxa delineation, using data integration by congruence. [ABSTRACT FROM AUTHOR]

The hydrographic survey is an important technology for improving maritime safety, especially in coastal waters. The accuracy of nautical charts and navigation publications is known to be directly related to hydrographic survey data. Therefore, this paper aims to investigate the status of a hydrographic survey by the International Hydrographic Organization (IHO) regions and identify the potentially risky IHO region for navigation safety. The fundamental step was to obtain the qualitative and quantitative data of the survey. Then, the presented analysis includes investigating the possible relationships between survey status and geographical characteristics by IHO regions. Considering that coastline length and sea surface data have not been calculated by regions, a quantum geographic information system was used to extract data. Using the presented methodology, the case study analyzes the data of stranded ships from 2010 to 2021 by IHO regions, estimates coastline length and sea surface by regions, and establishes the relationships between the coastline length, sea surface, and stranded ships. The results point out the need for improvement in the state of the hydrographic survey in almost all IHO regions and show a correlation between the sea surface and an adequate survey, as well as the coastline length and stranded ships. Hence, this research indicates the possibility of rationalizing the distribution of the IHO region concerning the sea surface and coastline length. [ABSTRACT FROM AUTHOR]

The biogeochemical cycling of mercury in aquatic environments is a complex process driven by various factors, such as ambient temperature, seasonal variations, methylating bacteria activity, dissolved oxygen levels, and Hg interaction with dissolved organic matter (DOM). As a consequence, part of the Hg contamination from anthropogenic activity that was buried in sediments is reinserted into water columns mainly in highly toxic organic Hg forms (methylmercury, dimethylmercury, etc.). This is especially prominent in the coastal shallow waters of industrial regions worldwide. The main entrance point of these highly toxic Hg forms in the aquatic food web is the naturally occurring phytoplankton. Hg availability, intake, effect on population size, cell toxicity, eventual biotransformation, and intracellular stability in phytoplankton are of the greatest importance for human health, having in mind that such Hg incorporated inside the phytoplankton cells due to biomagnification effects eventually ends up in aquatic wildlife, fish, seafood, and in the human diet. This review summarizes recent findings on the topic of organic Hg form interaction with natural phytoplankton and offers new insight into the matter with possible directions of future research for the prevention of Hg biomagnification in the scope of climate change and global pollution increase scenarios. [ABSTRACT FROM AUTHOR]

Accurate bathymetric data in shallow water is of increasing importance for navigation safety, coastal management, and marine transportation. Satellite-derived bathymetry (SDB) is widely accepted as an effective alternative to conventional acoustic measurements in coastal areas, providing high spatial and temporal resolution combined with extensive repetitive coverage. Many previous empirical SDB approaches are unsuitable for precision bathymetry mapping in various scenarios, due to the assumption of homogeneous bottom over the whole region, as well as the neglect of various interfering factors (e.g., turbidity) causing radiation attenuation. Therefore, this study proposes a bottom-type adaption-based SDB approach (BA-SDB). Under the consideration of multiple factors including suspended particulates and phytoplankton, it uses a particle swarm optimization improved LightGBM algorithm (PSO-LightGBM) to derive depth of each pre-segmented bottom type. Based on multispectral images of high spatial resolution and in situ observations of airborne laser bathymetry and multi-beam echo sounder, the proposed approach is applied in shallow water around Yuanzhi Island, and achieves the highest accuracy with an RMSE value of 0.85 m compared to log-ratio, multi-band, and classical machine learning methods. The results of this study show that the introduction of water-environment parameters improves the performance of the machine learning model for bathymetric mapping. [ABSTRACT FROM AUTHOR]

The alkalinity dynamics in coastal environments play a crucial role in controlling the global burial of carbonate minerals and the ocean's capacity to sequester anthropogenic CO2. This study presents results from high vertical resolution profiles obtained during two summers in the temperate Chesapeake Bay estuary, enabling detailed investigation of carbonate dynamics over salinity and redox gradients, along with measurement of the speciation of most redox-sensitive elements. Under oxygen-rich conditions, carbonate dissolution, primary production and aerobic respiration explain the evolution of total alkalinity (TA) versus dissolved inorganic carbon (DIC), once adjusted for fresh and oceanic water mixing. A significant flooding event in 2018 promoted carbonate dissolution. In oxygen-depleted waters, we observed a previously unreported 2.4 mol increase in DIC per 1 mol of TA production, which was consistent over the 2 years. Stoichiometric changes suggest that MnO2 reduction followed by Mn carbonate precipitation is responsible for this characteristic carbonate signature, likely produced in sediment pore water and then transferred to the water column along with other by-products of anoxic respiration at the onset of summer. Our findings highlight the critical role of Mn in alkalinity dynamics in the Chesapeake Bay and potentially other river-dominated environments where it can limit H2S oxidation to SO42- and promote sulfur burial. [ABSTRACT FROM AUTHOR]