Journal of Sea Research最新文献

The North Frisian Wadden Sea (NFWS), an open tidal basin within the UNESCO World Heritage Wadden Sea, is characterized by its barrier systems, tidal inlets, intertidal flats, and estuaries. Unlike its East Frisian and Dutch counterparts, the NFWS is underexplored in terms of residual sediment and flow transport pathways—knowledge crucial for coastal conservation and nature-based protection. These pathways are a product of complex interplay between tides, winds and waves that together shape the morphology of the NFWS. This study investigates these interactions using a high-resolution process-based model to perform a representative period simulation derived through a novel unfiltered-reduction technique. Our results reveal an anticlockwise residual flow circulation in the back-barrier region, which was not discernible in the residual sediment pathways. Waves primarily dictated sediment transport over intertidal flats, showing high variability in transport direction under energetic conditions. The coastline orientation and fetch size favored southward wavedriven sediment transport, opposing the northward residual flow transport driven by tidal propagation. A dynamic residual divergence pattern in the nearshore region of the barrier islands is also revealed for both sediment and flow, which moves alongshore during energetic events. The discussion compares these patterns and their implications with earlier local measurements, conceptual pathways, and different systems globally to provide a comprehensive overview of the transport dynamics in the NFWS.

To enhance storm surge forecasting and establish open boundary conditions for sophistical numerical simulation of tides and tidal currents in the Bohai Sea, Yellow Sea, and East China Sea, this study evaluated the accuracy of eight global and regional tide models (EOT20, FES2014, NAO.99Jb, TPXO9, DTU16, HAMTIDE12, OSU12, and GOT4.10c) based on 41 tide gauges in the region. The differences between tide models and 8 offshore tide gauges were notable, with the root mean square (RMS) values ranging from 12.67 to 25.97 cm for M₂, 6.09–13.73 cm for S₂, 2.96–6.56 cm for K₁, and 2.50–4.20 cm for O₁. For the offshore stations, the NAO.99Jb model demonstrated superior performance with the root square sum (RSS) value of 12.63 cm among the eight tide models. For the island and coastal stations, the EOT20 model performed the best for M₂ (RMS 13.03 cm), the FES2014 model for S₂ (RMS 6.26 cm), and the DTU16 model for K₁ and O₁ (RMS 2.73 cm and 2.26 cm, respectively). Overall, the EOT20 model also exhibited the lowest RSS value (15.22 cm) among the eight models for 24 island and coastal stations. The EOT20 model slightly outperformed others with the RSS of 14.88 cm across all 32 tide gauges. Regarding the Sa tidal component, great discrepancies were found between TIDAL CONSTANTS (TICON) harmonic constant data and tide gauges. The reason for this is that the Doodson number for the Sa tidal component derived from tide gauge data, which is influenced by meteorological factors, should be (0,0,1,0,0,0), while the TICON harmonic constant data employed the Doodson number of (0,0,1,0,0,−1) corresponding to the basic astronomical variables. A correction method was proposed to adjust tidal constants from inconsistent Doodson numbers. Comparing with the harmonic constants of the Sa tidal component at 28 coastal tide stations revealed large errors in the NAO.99b, FES2014, and EOT20 models, with RMS values of 19.03, 22.08, and 13.61 cm, respectively. Consequently, caution should be taken when using the Sa results from these ocean tide models.

The greatest purpose of this study is to analyze the importance of surface waves on the hindcasting of the oil spill through the Symphony wheel accident in the Qingdao coastal waters. During the accident period, a total of four synthetic aperture radar (SAR) images by Gaofen-3 (GF-3) were acquired from 2 to 19 May 2021. The hindcasting of two sea surface dynamics, namely currents and waves, is carried out using a coupled marine numeric model. This model, known as the finite-volume community ocean model-simulating waves nearshore (FVCOM-SWAVE), employs a triangular grid. Simulated significant wave height (SWH) is validated against remotely sensed product by the Haiyang-2B (HY-2B) altimeter on April 2021 yields a root mean square error (RMSE) of 0.38, a correlation coefficient (COR) of 0.78, and a scatter index (SI) of 0.34. Subsequently, Stokes drift estimated by waves are included to hindcasting oil spills using the oil particle-tracing method. The bias of the spatial coverage (SAR minus simulations) of an algorithm called the constant false alarm rate (CFAR) is −73.92 km² with Stokes drift, which is significantly less than the 55.45 km² coverage without Stokes drift. Moreover, compared with model-simulated oil spills, the bias of the geographic location at the center point with Stokes drift is 8.18 km, which is less than the 12.95 km bias without Stokes drift. These results demonstrate that Stokes drift needs to be included in the prediction of oil spills.

Teredinid bivalves (shipworms) are the main wood degraders in marine environments. However, little is known about the biological interactions between these marine wood borers and wood-associated biofouling species. Filter-feeding species and seaweeds are frequent biofoulers on the submerged wood. Using the marine xylophagous bivalve Bankia martensi (Stempell, 1899) as a model, we hypothesized that increasing the abundance of biofouling species on wood will decrease the recruitment and subsequent growth of the shipworm B. martensi. During the springs of 2020 and 2021, experiments manipulating biofouling cover were carried out using pine panels in Bahía Metri, southern Chile. Three experimental levels of biofouling cover were established (low: 0%–10%, intermediate: 40%–50%, and high: 90%–100%). After five months, the number of B. martensi perforations (as proxy as larval settlement density) and specimen sizes (length, width and volume) in the panels were measured. An inverse relationship between the perforation densities of B. martensi and biofouling cover on the wooden panels was observed. The most frequent biofouling species were mussels and seaweeds which tended to settle on the upper and lateral surfaces, while acorn barnacles and bryozoans were more frequent on the lower surface. Bankia martensi perforations were reduced with increasing biofouling cover. The number of perforations varied according to the panel surface, higher density on the upper and lateral surfaces and lower on the underside. Bankia martensi specimens were larger, both in length and in volume, in panels with low biofouling compared to intermediate and high biofouling cover, while width did not vary with treatment. Our results suggest that the biofouling cover decreases B. martensi recruitment and growth rates, which in turn reduces the wood degradation rate caused by this teredinid. Future manipulative experiments with selected biofouling species (filter-feeders, such as mussels and barnacles), as well as incorporating measurements of reproductive traits of shipworms could help in understanding the biological interactions between these marine communities of wood-boring and biofouling species.

Eddies have been observed at all depths and in all regions of the Arctic Ocean. However, given the complex geographic conditions and dynamic environments of this ocean, the synchronized observations of temperature, salinity, and currents, and the detailed analysis of individual eddies are still lacking in the Northwind Basin. Our study aims to address these research gaps. We observed an eddy from a mooring in the Northwind Basin in late October 2017. It is a large anticyclonic cold eddy within the Arctic halocline, with a maximum azimuthal velocity reaching 52.63 cm/s and a horizontal scale (~56 km) that significantly exceeds the first local baroclinic Rossby radius of deformation, i.e., it is in mesoscale. Its azimuthal velocity and scale are larger compared with those of nearby eddies, suggesting a relatively young state. This eddy possibly originated from the northern Chukchi Sea shelf, converging near Hanna Shoal with the Chukchi Slope Current before being advected northward into the Northwind Basin. Our study outlines detailed steps for extracting and analyzing eddies from mooring data and contributes to improving the understanding of the characteristics of Arctic Ocean eddies, providing a typical case for the investigation of eddies in the Northwind Basin.

Bioturbation in estuarine environments describes all sediment reworking processes implied in sediment transport. However, modelling at large spatial and temporal scales remains a challenge because of the need to consider the fauna at the community level, and because animal behaviour is highly seasonal with non-linear effects of macrofauna functional trait interactions. Bioturbation processes can be linked to the activity of organisms, based on the principle of energy ecology, linking the metabolic rate to the erodibility of a sediment colonised by benthic fauna. This study investigates this postulate by evaluating the erodibility parameters of a sediment subjected to: i) the bioturbation under seasonal temperature variations; ii) the synergistic bioturbation of different species. The experimental design consisted of: i) three temperature levels (winter, spring and summer), ii) three types of species duos (Cerastoderma edule and Macoma balthica; Scrobicularia plana and Hediste diversicolor; Corophium volutator and Peringia ulvae) at 4 different relative densities. Two successive experiments were carried out on the same individuals: measurement of oxygen consumption of fauna then measurement of the erodibility of the colonised sediment in a flume. The oxygen consumption confirmed that the metabolic rate is a good model of the fauna respiration, regardless of species. The erosion results indicated that the metabolic rate in the case of the fluff layer resuspension is an interesting descriptor for 1) the assessment of the bioturbation under variable temperatures and 2) the integration of the two different bioturbator species that could co-occur in the same habitat. In contrast, the effect of bioturbation on the mass sediment erosion threshold cannot be easily modelled by using the metabolic rate and the classification in functional groups is required. Bioturbation models of the fluff layer using metabolic rate is a promising tool for modelling the effects of faunal communities on sediment transport at the scale of an estuary and over the long term, even projected in the context of global warming.

Since 2018, severe and recurrent copepod depletions have been observed in Belgian coastal waters. These depletions have been described as temperature-induced mass mortality events. This paper confirms the relation of copepod abundance anomalies with periods of high temperature based on new data. Although severe, the effects, consequences and implications of this depletion remain unknown. Our study suggests that the absence of zooplanktonic predators in autumn, together with the availability of nutrients discharged via the Scheldt estuary, allowed a bloom of the diatom Bellerochea, in a season otherwise characterised by low phytoplanktonic activity. Although the bloom reaches high abundances, its effects on the marine environment are not yet visible. The enormous abundances are likely to induce small-scale oxygen depletions which might further translate to the environment. Communities of Calanoida, Canuelloida and Cyclopoida tend to recover from the annual autumn depletion, although the typical autumn peak is entirely missing in the years subject to severe heat waves and associated high water temperatures. As a result, copepod dynamics have drastically changed since the first observed depletion and associated bloom of Bellerochea in 2018.

Understanding the amino acid (AA) composition of phytoplankton-derived particulate organic matter (POM) is crucial for unraveling phytoplankton physiology and assessing food quality. This study investigated AA compositions and food quality of POM associated with two phytoplankton groups in the Ross Sea polynya. The Phaeocystis antarctica (P. antarctica)-predominant group, with P. antarctica overwhelmingly contributing to its composition, demonstrated a fresh state and heightened physiological activity. In contrast, the P. antarctica and diatoms-mixed group exhibited superior essential amino acids (EAAs) contributions and a higher EAA index (EAAI), indicating enhanced food quality. Dissimilarity Index values provided nuanced insights into degradation stages not captured by other indices. Despite lower physiological activity, diatoms in the mixed group stood out as crucial sources of high-quality nutrition for higher trophic levels in the Ross Sea polynya. The observed variations in AA compositions not only reflected the phytoplankton community structure but also provided insights into their physiological conditions. Given the ongoing climate-induced environmental changes potentially influencing phytoplankton communities, this study underscores the potential impacts on the intricate food web dynamics in the Ross Sea polynya. The assessment of AA composition emerged as a valuable tool for understanding the ecological implications for higher trophic levels in this polar region.

The scour protection layer (SPL) is a layer of large stones placed around man-made structures in the marine environment, preventing sediment scouring while also providing new hard substrate and potentially increasing the structural complexity of the original environment. This fosters development of diverse benthic communities, supporting high abundance of organisms. Future SPLs are therefore a potential tool for the ecological enhancement of degrading marine habitats following the principles of nature-inclusive design. Yet, factors that shape the benthic communities on SPLs are poorly understood. Here, we analysed existing data from SPLs from offshore wind farms and a gas platform in the southern North Sea to determine how SPL characteristics affect the biofouling community structure. We combined this analysis with an in-situ experiment testing for the effects of habitat complexity on SPL communities. Our results demonstrate that abundant and diverse communities are present on all SPLs. On a regional scale, communities are mainly affected by depth and location. Increasing habitat complexity has significant and positive effects on species richness yet was non-significant for biomass and abundance of the biofouling community. If applied thoughtfully, nature-inclusive design of the SPL habitat, including manipulation of the physical complexity of the structure, can effectively promote biodiversity.

The mechanical properties of glass fiber composite structures prepared by vacuum forming manufacturing process are influenced by various factors and have a certain degree of dispersion, resulting in unclear durability characteristics when applied in corrosive seawater engineering. Firstly, a variety of resin materials for underwater protective structures are tested for seawater degradation, and excellent resins that can still ensure the structural load-bearing capacity and stability after immersion are selected. Secondly, based on relevant standards and specifications, the article conducted seawater immersion aging tests at room temperature and accelerated seawater immersion aging tests at 60°C on glass fiber specimens of 430 epoxy bisphenol vinyl resin and 1967 polycyclic pentadiene resin. Finally, the degradation characteristics of strength, modulus, and impact toughness of the specimens were obtained through a series of mechanical property tests, such as bending, compression, shear and impact, under different aging time periods in room temperature and 60°C seawaters, respectively. The article summarizes the differences in the durability and mechanical properties degradation of large glass fiber protective structures with different resins during seawater immersion.