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Urban centers line western Lake Ontario where urban rivers, wastewater treatment plants and stormwater load nutrients, major ions and suspended solids to the nearshore. In 2018, nearshore water quality and associated physical conditions bordering the cities of Toronto and Mississauga were assessed as a benchmark for future effects of urban growth and municipal infrastructure projects to improve water quality. Conductivity and UV-fluorescence were used as water quality surrogates and mapped over blocks of shoreline stratified by distance offshore. Patterns in UV-fluorescence aligned with loading points, and generally higher levels near the shoreline, were correlated with concentrations of nutrients, major ions and suspended solids. Water quality was more land-impacted over the shoreline from the Credit River to Humber Bay contrasting with the more lake-like conditions from Toronto Eastern Beaches to the Rouge River. Within Toronto Harbour, cross-harbour gradients in water quality varied with weather-related changes in river and storm water loading. Mixing areas at wastewater treatment plant outfalls and tributary mouths, frequently shaped by alongshore lake circulation, resulted in a mosaic of water quality over the shoreline. Area-wide elevation of chloride and conductivity, and poorer water quality in late spring, was linked to heightened river discharge. Thermal stratification affected how discharges were distributed in the water column, but measurements at the lake surface reflected the strongest overall land-effects on water quality. The patterns of temporal-spatial variability identified within geographically-defined areas of shoreline can be used as past footprints in future monitoring to detect change. [ABSTRACT FROM AUTHOR]

The extent of nutrient enrichment over the urbanized shoreline of western Lake Ontario bordering the Cities of Toronto and Mississauga was investigated in 2018. Concentrations of total phosphorus were higher and more wide-ranging compared with nearshore reference areas in eastern Lake Ontario. Area-weighted chlorophyll a was higher over the shoreline from the mouth of the Credit River to Humber Bay west of Toronto Harbour compared with that to the east from the Toronto Beaches to the Rouge River, a pattern also seen broadly in concentrations of phosphorus fractions and nitrates. Concentrations of phosphate measured by mass spectrometry, and using an internal standard to minimize sampling losses, were higher in Toronto Inner Harbour, near wastewater outfalls, river mouths, and to varying extent over the mixing areas of these discharges. Chlorophyll a suggested broadly oligotrophic to oligo-mesotrophic conditions despite areas with nutrient fractions suggestive of more productive conditions. Toronto Inner Harbour was mesotrophic, with wide-ranging levels of phosphorus fractions strongly influenced by the variable loading from the Don River into the harbour. Phosphorus fractions in the harbour quays which also receive CSOs discharges were elevated at times. Blooms or scums of planktonic algae were not observed. Elevated concentrations of phosphate were found at shallow depths suitable for growth of the green algae Cladophora. As these urban areas continue to grow, the potential for additional nutrient loading to exacerbate growth of algae should be watched given the present conditions that indicate variable but pervasive nutrient enrichment. [ABSTRACT FROM AUTHOR]

Coastal management and engineering applications require data that quantify the nature and magnitude of changes in nearshore bathymetry. However, bathymetric surveys are usually infrequent due to high costs and complex logistics. This study demonstrates that ground‐based X‐band radar offers a cost‐effective means to monitor nearshore changes at relatively high frequency and over large areas. A new data quality and processing framework was developed to reduce uncertainties in the estimates of radar‐derived bathymetry and tested using data from an 18‐months installation at Thorpeness (UK). In addition to data calibration and validation, two new elements are integrated to reduce the influence of data scatter and outliers: (a) an automated selection of periods of “good data” and (b) the application of a depth‐memory stabilization. For conditions when the wave height is >1 m, the accuracy of the radar‐derived depths is shown to be ±0.5 m (95% confidence interval) at 40 × 40‐m spatial resolution. At Thorpeness, radar‐derived bathymetry changes exceeding this error were observed at time scales ranging from 3 weeks to 6 months. These data enabled quantification of changes in nearshore sediment volume at frequencies and spatial cover that would be difficult and/or expensive to obtain by other methods. It is shown that the volume of nearshore sediment movement occurring at time scale as short as few weeks are comparable with the annual longshore transport rates reported in this area. The use of radar can provide an early warning of changes in offshore bathymetry likely to impact vulnerable coastal locations.Plain Language Summary: Near the shore, waves and currents can cause natural changes in seabed elevation (due to removal or deposition of mud, sand, and gravel). On the other hand, changes in seabed elevation can alter the waves approaching the shore and influence the location and amount of coastal erosion. Measurements of these changes are required for coastal management and a wide range of engineering works. However, surveys of the seabed are usually infrequent owing to high costs and logistical difficulties. This paper analyses data from a marine radar installed on a cliff top to produce a series of seabed elevation (bathymetric) maps off the Thorpeness coast (UK). A new data quality assessment was developed to produce improved estimates of water depth. Results demonstrate that radar can offer a cost‐effective alternative to conventional surveys and enable frequent monitoring of the seabed over large areas. The use of radar in the present study enabled the measurement of changes in nearshore seabed elevation within periods as short as 3 weeks. Radar‐derived bathymetric maps can provide an early warning of seabed changes and allow more time to plan and implement responses to mitigate the impacts of coastal erosion.Key Points: Uncertainty in radar‐derived bathymetry (2.5–10‐m depths) was greatly reduced using a new data processing and quality control frameworkBathymetry changes assessed for periods as short as 3 weeks were shown to be accurate to ±0.50 m at a 40 × 40‐m resolutionThe volume of nearshore sediment movement over a few weeks was comparable with annual longshore transport rates reported in this area [ABSTRACT FROM AUTHOR]

ABSTRACT: Explorations of the dynamics of nearshore regions of the coastal zone are missing from many efforts to understand larval transport and delivery to suitable habitats. Larval distributions in the coastal ocean are variable and depend on physical processes and larval behaviors, leading to biophysical interactions that may increase larval retention nearshore and bolster their return to natal sites. While recent evidence suggests that many larvae are retained within a few kilometers from shore, few studies incorporate measurements sufficiently close to shore to plausibly assess supply to the shoreline benthos. We measured cross-shore distributions of larvae of benthic crustaceans between 250 and 1100 m from shore (i.e. just beyond the surf zone) within the coastal boundary layer (CBL)-a region of reduced alongshore flow-and simultaneously quantified a suite of physical factors that may influence larval distributions. We found high larval abundance within the CBL, with a peak at 850 m from shore, and a decrease in abundance along the shoreward edge of the sampled transect. We also found distinctly different larval assemblages at outer stations within the CBL, as compared to inner stations that are more influenced by shoreline dynamics. These patterns persisted across sample dates, suggesting that the spatial structure of nearshore larval assemblages is at least somewhat robust to temporal changes in physical conditions. Thus, while larval abundance appears to be high within the CBL, larvae appear to be sparse within the narrow band of water adjacent to the surf zone. Low larval supply adjacent to suitable habitats has important implications for the coupling of supply and recruitment, and resulting dynamics of shoreline populations.© Inter-Research 2013. www.int-res.com.

Coccolithophores, common primary producers in Mesozoic, Cenozoic, and present oceans, are significant components of the earth's biogeochemical cycles. Being the most productive calcifying organism on earth, their carbonate oozes play a major role in fixing CO2, thereby forming the most important long‐term CO2 sink throughout the last 100 Ma. Our understanding of their fossil ancestors is mainly based on data from chalk sequences. Generally, the Cretaceous chalks were deposited at water depths of ≥200 m under stable, pelagic conditions. Here we report on remarkably diverse fossil coccolithophore assemblages from Cenomanian‐Campanian (100‐72 Ma) nearshore deposits, with estimated water depths of ≤40 m. For interpreting the findings in a broader paleoenvironmental context, we additionally analyzed contemporaneous chalk material from the Santonian‐Campanian (86‐72 Ma) interval. Highly diverse coccolithophore associations (50–81 species/sample) characterize the nearshore setting, while the contemporaneous chalk samples are less diverse (43–54 species/sample). The absolute abundances of coccoliths from the nearshore setting are by a factor 2–10 lower than those from the chalk, diversity indices are by 20%–30% higher (Shannon Index = 2.94–3.46) in the nearshore sediments. The presence of highly diverse coccolithophore communities in nearshore settings provides new insights into their paleoecology and evolution and the paleoceanography of the Late Cretaceous. Our data revise the traditional view of coccolithophores being typical open ocean dwellers. Extreme nearshore settings of the Late Cretaceous greenhouse world were characterized by environmental conditions equating those of the hemipelagic realm but supplying a larger variety of ecological niches. Plain Language Summary: Coccolithophores, a group of marine, unicellular algae, are very common in past and present oceans. Via photosynthesis they produce sugars and fix CO2, thereby forming with other plants the base of the current marine ecosystem. By forming an external, calcitic (CaCO3) skeleton, coccolithophores play a major role in fixing CO2, they have been the most important long‐term CO2 sink for the last 100 million years. Drifting in the uppermost 150 m of the open oceans, their minute tests (∼40 µm diameter) accumulated substantial amounts of carbonate sediments in the oceans. During the Late Cretaceous period (100‐66 Ma), high abundances of these shells formed the widespread chalk deposits (e.g., the cliffs of Dover), which are mainly composed of the calcitic remains of coccolithophores. Being well documented from open ocean settings, data from nearshore environments are rare. Here we present extremely rich and diverse coccolithophore assemblages from a coastal setting. Diversities are much higher than in the contemporaneous open‐oceanic chalk samples. The new data have substantial implications for (a) understanding the ecology of coccolithophores, (b) reconstructing the Late Cretaceous greenhouse world environment, (c) better predicting a scenario of how the future marine biogeochemistry of our planet might look like. Key Points: Coccolithophore abundance and diversity patterns from nearshore and offshore deposits of Late Cretaceous age (100‐66 Ma) have been studiedThe shallow‐marine successions of the Late Cretaceous greenhouse world provided, unexpectedly, highly diverse coccolithophore assemblagesThe findings allow to reconstruct Late Cretaceous marine environments and the paleoecology of coccolithophores [ABSTRACT FROM AUTHOR]

Fixed acoustic Doppler current profiler (ADCP) velocity measurements are used to investigate headland vorticity generation and recirculation in ∼20 m depth around the small (∼1 km) central California headland Pt. Sal. To reduce vorticity estimation noise, velocities are reconstructed from the first two Empirical Orthogonal Function modes representing ≈73% of the variance. Using fixed ADCPs, depth‐averaged vorticity is estimated west and south of Pt. Sal. Only one west‐location vorticity component is estimated, leading to negative vorticity bias for northward flow. The south location vorticity is consistent with estimates from parallel vessel transects on one day. The observed depth‐averaged flow V was primarily along‐bathymetric contours and varied ±0.2 ms−1 across subtidal and tidal frequency bands. The depth‐averaged normalized vorticity ζ¯/f varied ±8 across all frequency bands. Vorticity distributions are skewed with opposite sign at west and south locations, and ζ¯/f<−1 is more likely at the west location. At both locations, depth‐averaged vorticity and velocity are inversely related, with relationship asymmetric with sign of V, indicating headland and farther upstream vorticity generation. Binned‐mean ζ¯/f depends on both V and its time‐derivative, and indicates vorticity recirculation across the headland. The ∼2 h vorticity adjustment timescale and the associated short excursion distances indicate vorticity generation between south and west locations. Potential vorticity changes across the headland are different for positive and negative V indicating headland asymmetric vorticity generation. Pt. Sal occupies a nondimensional parameter space that is unique relative to other well studied headlands. Plain Language Summary: Coastal ocean flows past topographic features, such as headlands and islands, lead to a variety of processes which can enhance how much mixing and stirring occurs and have implications on the movement of marine biota and sediment. One measure of this mixing and stirring is 'vorticity,' which is a gauge of how fast the water spins. Observations from September and October 2017 are used to investigate how vorticity is created and moved around the small (∼1 km) central California headland Pt. Sal. Raw data are filtered using statistical methods to remove noise. Vorticity is estimated west and south of Pt. Sal from groups of fixed instruments measuring flow speed and direction. Separate vorticity observations from a pair of research vessels corroborate the fixed observations on a single day. Currents at the headland were a mix of oscillatory tidal (twice a day) and longer time‐scale flows. The generation of vorticity is found to be stronger for northward flow relative to southward flow. The vorticity can also recirculate back with the oscillatory tidal flow. Pt. Sal is a unique study site, especially relative to other well studied headlands which are either larger in size or in deeper water. Key Points: At a 1 km scale headland (Pt. Sal CA), depth averaged vorticity varied {plus minus}8f and was asymmetrically related to along‐headland flowVorticity also depends on flow acceleration, indicating short (2 h) adjustment timescale, recirculation, and headland generationEstimated potential vorticity across the headland indicates asymmetric vorticity generation stronger for northward flow [ABSTRACT FROM AUTHOR]

Future nearshore wave energy converter (WEC) arrays will influence coastal wave and sediment dynamics, yet there are limited numerical methodologies to quantify their possible impacts. A novel coupled WEC-Wave numerical method was developed to quantify these possible influences on the nearshore coastal wave climate. The power performance of an Oscillating Surge Wave Energy Converter (OSWEC) array was simulated to quantify the wave energy dissipation due to the array. The OSWEC’s effect on the local wave climate was quantified by a novel coupling of two numerical models, WEC–Sim and XBeach. WEC–Sim characterizes the power extraction and wave energy transmission across the OSWEC, while XBeach captures the change in wave dynamics due to the WEC and propagates the waves to shore. This novel methodology provides the ability to directly quantify the impact of the effect of a WEC array on the local wave climate. Three case studies were analyzed to quantify the impact of a single WEC on breaking conditions and to quantify the impact of number of WECs and the array spacing on the local nearshore wave climate. Results indicate that when the WEC is placed 1100 m offshore, one WEC will cause a 1% reduction in wave height at the break point (Hsbp). As the WEC is placed further offshore, the change in Hsbp will become even smaller. Although the change in wave height from one WEC is small, WEC arrays magnify the cross–shore extent, area of influence and the magnitude of influence based on the spacing and number of WECs. For arrays with 10 or 15 WECs, the cross–shore extent was on average 200–300 m longer when the WECs were placed one to two WEC widths apart, compared with being spaced three or four widths apart. When the spacing was one WEC width apart (18 m), there was a 30% greater spatial impact on the nearshore region than arrays spaced three or four widths apart. The trend for the average transmission coefficient is within 5% for a 5, 10 or 15 WEC array, with a cumulative average of 78% transmission across all conditions.

Research on plastic pollution has rapidly expanded in recent years and has led to the discovery of vast amounts of microplastics floating on the surface of subtropical oceanic gyres. However, the distribution of floating plastic in the ocean is still poorly constrained, and there is a lack of information from a few meters from the coastline where the largest plastic emissions take place. Here, we provide a comprehensive study on the loads of plastic debris in the coastal surface waters of the NW Mediterranean Sea using data from 124 manta trawl deployments collected along 7 months by citizen scientists. Our results reveal that pollution by microplastics in the nearshore is likely subject to seasonal variations associated to a combination of hydrodynamic and anthropogenic pressures. The high proportions of microplastics found indicate that potential breakdown of plastics in the nearshore may take place in line with previous works. We prove that citizen science is a powerful tool in plastic research to monitor microplastics in the nearshore as it provides scientifically meaningful results while stimulating citizen engagement. Future studies may benefit from targeting specific scientific open questions by using the citizen science methodological approach presented here.

In this study, we present results on fatty acid analysis of phytoplankton of Lake Baikal, the world’s deepest lake, which differs from other lakes by its oceanic features. Since we used a large-mesh net, the net sample phytoplankton were primarily represented by the large elongated diatom Synedra acus. subsp. radians (Kützing) Skabichevskij. The similar algae composition of net samples of spring season phytoplankton collected at different sites of the lake allows us to compare results of the fatty acid analysis of these samples. The phytoplankton diversity of the sedimentation samples was contrary represented by 32 algae species. There are clear changes in the fatty acid composition of net phytoplankton exposed to anthropogenic impacts of varying intensity. The content of polyunsaturated fatty acids in phytoplankton collected from central stations (pelagic stations at a distance of ~10–30 km from the shoreline) without anthropogenic impact was higher by up to 15% than phytoplankton collected from nearshore stations (littoral stations at a distance of ~0.01–0.05 km from the shoreline) and offshore stations (pelagic stations at a distance of ~3 km from the shoreline). The interlaboratory precision of fatty acid determination of phytoplankton is estimated as ≤10%. We found high content of the lipid peroxidation marker (80–340 μg g−1 of dry weight) in phytoplankton from nearshore and offshore stations with intensive anthropogenic impact. In phytoplankton from central stations, we did not find any lipid peroxidation. Determination of unsaturated fatty acids, coupled with analysis of fatty acid peroxidation products, can be used to evaluate the level of anthropogenic impact in terms of ecological health and biodiversity conservation.

The effects of two contrasting environmental conditions in nearshore waters off central Chile on the diet and morphospace of two cohorts of larval labrisomid blenny Calliclinus geniguttatus were studied using geometric morphometrics and gut content analysis. The two environmental conditions corresponded to (a) a cold period with upwelling‐favourable southwesterly winds and a mixed water column of cooler water and (b) a warm period with calm winds and stratified warmer water. During the cold period, fish larvae had a more hydrodynamic head shape, longer jaws and a higher feeding incidence, suggesting a greater food supply due to upwelling events and a possible increase in encounter rates in the turbulent environment. In contrast, the larvae from the warm period had a more robust head shape with smaller jaws and a lower feeding incidence, which was related to higher water temperatures and lower wind intensities. The present study suggests that larvae have a rapid response to environmental changes on a short time scale (i.e., from weeks to months), showing a link between environmental conditions and changes in the phenotypic traits and diet of the larval stages of this cryptobenthic species. [ABSTRACT FROM AUTHOR]

Almar, R.; Bergsma, E.W.J.; Gawehn, M.A.; Aarninkhof, S.G.J., and Benshila, R., 2020. High-frequency temporal wave-pattern reconstruction from a few satellite images: A new method towards estimating regional bathymetry. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 996-1000. Coconut Creek (Florida), ISSN 0749-0208. It is currently impossible to accurately estimate coastal risks considering the lack of accurate and up-to-date bathymetric knowledge. We enter a new era of satellite coastal observation which offers unprecedented regional monitoring capabilities with a high spatial resolution. Methodologies to estimate bathymetry from waves developed for shore-based video camera systems are now widely used but require high frequency (several frames per second) and long duration (a few minutes) videos. Only a few satellite missions offer the possibility to acquire videos from space over regional domains (Pleiades persistent mode, WorldView-2). These are on-demand acquisitions at specific dates and generally expensive. At the same time, most of continuous Earth Observation missions, which have the potential to cover coastal evolution, offer short sequences using the different bands (2 to 10 bands within typically ∼1-2 seconds, e.g. Sentinel-2) or a sequence of a few images for stereo or tri-stereo topography purpose (2 or 3 images with lags of ∼8s, e.g. Pleiades). Here, we present how high-frequency wave pattern time-series can be reconstructed using a spatiotemporal cross-correlation, gathering surrounding sparse temporal wave information while conserving its high-resolution spatial information. This new methodology breaks several locks and enables deriving full wave characteristics from a limited number of images to quantify a robust regional bathymetry. [ABSTRACT FROM AUTHOR]

Changes in sea surface temperature (SST) and sea surface salinity (SSS) in response to the binary typhoons Sarika and Haima (2016) in the offshore and nearshore areas along the Guangdong Province Coast (GPC) and Hainan Island Coast (HIC) in the northern South China Sea are comprehensively investigated using multi-satellite observations and ocean reanalysis data. The results show that the maximum SST cooling was 2.5°C (average 1.5°C) and 6°C (average 2.5°C) after the passage of typhoon Sarika in the HIC nearshore and offshore, respectively. In contrast, the average SST cooling was 1°C in the GPC offshore and very marginal in the GPC nearshore after the passage of typhoon Haima. For SSS, typhoon Sarika induced changes of 0.1 psu and 0.35 psu in the HIC nearshore and offshore, respectively, while typhoon Haima caused changes of -0.1 psu and 0.3 psu in the GPC nearshore and offshore, respectively. The responses of both SST and SSS are similar in the offshores of both the GPC and the HIC. However, they are quite different in the nearshores of the GPC and the HIC. It is found that the nearshore responses to typhoon are quite different depending on the coast conditions: river discharge and advection of coastal current. In the GPC nearshore, the river discharge due to typhoon can lead to larger SSS decrease than that in the HIC nearshore. Besides, the advection of coastal high SSS water from the GPC to the HIC along coast made SSS decrease in the GPC but increase in the HIC. As a result, the SST and SSS responses are easily to be influenced, while they could exist much longer in the offshores. [ABSTRACT FROM AUTHOR]

Based on 2 RADARSAT-2 SAR (Synthetic Aperture Radar) SLC (Single Look Complex) data and the cross-spectrum method, the distributions of significant wave heights and mean wave periods of ocean wave were inverted, and the distributions of the wave power density, which can represent the wave power, were calculated. Some comparisons between the results of the SAR and those of the ECMWF (European Center for Medium-Range Weather Forecasts) dataset were carried out, and the observation ability for the distribution characteristics of wave and wave power by the SAR was studied in detail. The results show that compared with buoys, which are single-point observations, and wave models, which are simulated observations, the SAR is an ideal tool for extensive wave observations in nearshore waters. The advantage of SAR observations is that some fine structure and microcosmic changes in wave and wave power can be found, which helps us understand the internal structure and transformation patterns of wave better. Therefore, the SAR showed extremely extensive application prospects in the field of wave observations. The contributions in this paper will provide some references for researchers aiming for ocean wave detection by remote sensing and promote the application level of SAR in the detection of wave and wave power. [ABSTRACT FROM AUTHOR]

Nahirnick, N.K.; Costa, M.; Schroeder, S., and Sharma, T., 2020. Long-term eelgrass habitat change and associated human impacts on the west coast of Canada. Journal of Coastal Research, 36(1), 30–40. Coconut Creek (Florida), ISSN 0749-0208. Eelgrass (Zostera marina) forms a critical nearshore marine habitat in temperate coastal ecosystems. For three small estuaries in the Southern Gulf Islands of British Columbia, changes in eelgrass area coverage and shape index (over the period of 1932–2016) were assessed using historical aerial photographs and unoccupied aerial system (UAS) imagery. In addition, changes in eelgrass area and shape index were evaluated in relation to landscape-level coastal environmental indicators, namely shoreline activities and alterations and residential housing density. All three eelgrass meadows showed a deteriorating trend in eelgrass condition; on average, eelgrass area coverage decreased by 45.1%, while meadow complexity as indicated by the shape index increased by 66.3%. Shoreline activities (boats, docks, log booms, and armoring) and residential housing density increased markedly at all sites over the study period and were strongly correlated to eelgrass area coverage and shape index. Changes in these landscape-level indicators over this period corroborate the observed decline in eelgrass habitat condition, because they suggest an overall deterioration of coastal environmental health in the Salish Sea due to increased use of the coastal zone, as well as declines in water quality due to urbanization. [ABSTRACT FROM AUTHOR]

Despite their ecological and economic importance, coastal biological communities and ecosystem processes in large lakes have been understudied compared to those offshore. We investigated temporal variability in the abundance and assemblage composition of coastal organisms in northern Lake Michigan. We sampled nutrients, phytoplankton, zooplankton, periphyton, benthic invertebrates, and fish along the east coast of Beaver Island, Michigan, USA, with high temporal frequency (every d to every 2 wk) over 2 summers. We also examined connectivity between coastal and offshore habitats with both hourly water current data from the Great Lakes Coastal Forecasting System and sampling offshore 2 to 3× per summer. The abundance of littoral zone organisms varied markedly on daily to weekly timescales for both benthic invertebrates and water-column organisms (phytoplankton, zooplankton, fish). For example, zooplankton abundance changed by a mean of 297% between sampling dates at the same location. Within-season peaks in plankton abundance also differed among years. Specifically, peak chlorophyll a (Chl a) concentrations were observed 1 mo earlier in 2016 than 2015, and early summer (Jun) zooplankton abundance was 333% higher in 2016 than 2015. Furthermore, our data suggest that water currents may influence the abundance and assemblage composition of plankton, possibly by altering the flux of nutrients and organisms from offshore to coastal habitats. Specifically, zooplankton abundance increased by a mean of 194% when surface currents moved eastward before we sampled, and eastward surface velocity significantly altered zooplankton assemblage composition. Chl a concentration increased by a mean of 106% when surface currents moved northward prior to sampling. In contrast, the abundance and composition of benthic invertebrates and fish differed among sites and was not significantly related to water currents. The abundance of these organisms also declined throughout the summer. Therefore, benthic and water-column organisms are controlled by different processes, so patterns in their local abundance are out of sync. Understanding variability in coastal communities may enhance monitoring and design of effective protocols for investigating large lake ecology. Further, understanding the importance of regional movement of nutrients and organisms may be key to understanding community and ecosystem structure in coastal areas. [ABSTRACT FROM AUTHOR]

The intertidal beach profile provides coastal engineers and managers with a good indication of the current state of a sandy coastline, however regular beach profile measurements are time consuming and expensive to obtain using conventional surveying methods. The potential to reconstruct the intertidal beach profile from measurements of reflected waves is tested here using three field datasets covering a different range of hydro-morphological conditions from dissipative, to reflective. The swash is found to behave as a low-pass filter on reflected waves, with a cut-off frequency that primarily depends on the swash slope. An agreement is found between video-derived swash spectrum saturation tail and the shortest reflected waves, computed from deep water directional wave measurements. By integrating this swash slope over a tidal cycle, the shape of the intertidal beach profile can be reconstructed. Our results clearly show the potential of such method to estimate complex intertidal beach profile, such as double-slope beaches. • The intertidal beach profile can be reconstructed by integrating the swash slope over a tidal cycle. • The swash behaves as a low-pass filter, with a cut-off frequency that primarily depends on the swash slope. • A good agreement is found between video-derived swash spectrum saturation tail and the shortest reflected waves. [ABSTRACT FROM AUTHOR]

Ecological studies that span multiple marine depositional environments frequently find that benthic invertebrate assemblages are correlated primarily with an onshore-offshore gradient. Variability within the same depositional environment is inferred to not result from water depth differences, but other parameters such as substrate consistency and shear stress. Modern studies focusing on assemblage variations within the same depositional environment can identify which variables affecting assemblage compositions are independent of water depth. This study examines the environmental controls on the composition of molluscan death assemblages from the shallow subtidal environments of San Salvador Island. Molluscan assemblages were tabulated from twenty-nine bulk samples collected from four locations around San Salvador Island representing seagrass meadows, open sandflats, and patch reef systems common in the shallow subtidal. In addition, quantitative environmental data for each sample was characterized, including seagrass density, water depth, temperature, pH, dissolved oxygen, and grain-size, as well as qualitative observations of wave energy and bioturbation. Cluster analysis and canonical correspondence analysis (CCA) were performed to identify environmental gradients associated with molluscan assemblage composition. Cluster analysis and CCA Axis 1 identify seagrass coverage and substrate consistency as the primary environmental variables describing molluscan death assemblage compositions. CCA Axis 2 identifies wave energy, bioturbation, and dissolved oxygen as the secondary environmental variables, though the small range of dissolved oxygen values (17–21 mg/L) collected using single, instantaneous measurements make it unclear whether the oxygen gradient is ecologically significant for our time-averaged assemblages. Our analysis demonstrates the variability of assemblages within a single depositional environment, as well as the utility of fine-resolution studies for identifying secondary environmental variables that control the composition of marine invertebrate assemblages. • Assemblages from vegetated sites are distinct from unvegetated sites. • Seagrass and grain size are primary variables affecting subtidal death assemblages. • Wave energy, bioturbation, and dissolved oxygen are secondary variables. • Water depth gradient still identifiable within the shallow subtidal environment. [ABSTRACT FROM AUTHOR]

Coastal upwelling and other oceanographic processes, exert influences on phenotypic traits of early life stages of marine fishes. However, it remains to elucidate the environmental effects on the morphology of fish larvae. Using geometric morphometrics and otolith microstructure of a temperate rocky reef fish, the labrisomid blenny Auchenionchus crinitus (Labrisomidae), we studied the larval growth, mortality and morphospace of four consecutive cohorts, hatched between austral winter and summer off central Chile. We hypothesize that coastal environmental conditions will influence early life traits of this cryptobenthic fish. The winter cohort, which inhabited colder and well-mixed nearshore waters, grew more slowly and had a more hydrodynamic head shape, while the summer cohort, which lived in warmer and stratified waters, grew faster, but had a more robust shape. Cohorts expressed less ontogenetic allometry as seasons progressed, suggesting that the seasonal increment in water temperature reduces the shape changes with size during larval development. Also, slower- and faster-growing larvae showed large variation from the consensus shape, e.g. had the largest shape disparity. Nonetheless, all cohorts showed similar mortality rates during the first month of life. Finally, increases in zonal wind stress (i.e. sea breeze) and decreases in the sea temperatures (i.e. upwelling events) increased the growth rates of older (> 15 days old) larvae. Therefore, for this cryptobenthic species, differences in growth rate and body shape are related to the seasonal increase in water temperature, and local-scale meteorological conditions. [ABSTRACT FROM AUTHOR]

Nearshore wind development has been seen as the cost-reducing option that could shrink the cost gap between onshore and offshore development. The cost advantage is linked to more shallow water and shorter connection to shore even avoiding an offshore substation. Public tendering for offshore wind in Denmark has opened up for near-shore wind turbine farms as an alternative for lowering the cost of new offshore wind development. Whether these proposed near-shore locations will manage to significantly lower costs is not clear. The tenders have resulted in bids that are at comparable levels for the nearshore and the further offshore wind farms. We compare the cost drivers and possible cost differentials with preferences for locating wind farms further away from the coast. The primary cost driver is water depth, and in the Danish case water depth is increasing slowly or is not even correlated with the distance from shore. Therefore the willingness to pay for moving turbines away from the coast may be sufficiently high to balance the increased cost. The actual comparison of costs and willingness to pay must be carried out for the specific case with cost characteristics and willingness to pay by the affected population. Unlabelled Image • Nearshore development may potentially bring down cost for offshore wind • Nearshore wind farms have same cost drivers as further offshore wind • LCOE is declining for offshore wind and water depth is the most important cost driver • In Denmark recent cost estimates from offshore tenders show reduced costs and low variation in actual water depth • Results indicate possible willingness to pay above the costs for moving wind farms away from extremely close to shore locations [ABSTRACT FROM AUTHOR]

There is growing interest in the use of Unoccupied Aerial Systems (UAS) for mapping and monitoring of seagrass habitats. UAS provide flexibility with timing of imagery capture, are relatively inexpensive, and obtain very high spatial resolution imagery compared to imagery acquired from sensors mounted on satellite or piloted aircraft. However, research to date has focused on UAS applications for exposed intertidal areas or clear tropical waters. In contrast, submerged seagrass meadows in temperate regions are subject to high cloud cover and water column turbidity, which may limit the application of UAS imagery for coastal habitat mapping. To test the constraints on UAS seagrass mapping, we examined the effects of five environmental conditions at the time of UAS image acquisition (sun angle, tidal height, cloud cover, Secchi depth and wind speed) and five site characteristics (eelgrass patchiness and density, presence and density of non‐eelgrass submerged aquatic vegetation, sediment tone, eelgrass deep edge and site exposure) at 26 eelgrass (Zostera marina) monitoring sites in British Columbia, Canada. Eelgrass was delineated in UAS orthomosaics using object‐based image analysis, combining image segmentation with manual classification. Each site was ranked according to the analysts' confidence in the delineated eelgrass. Robust Linear Regression revealed sun angle and 'theoretical visibility' (an aggregate of tidal height, Secchi depth, and eelgrass deep edge conditions) to be the most important variables affecting mapping confidence. In general, ideal environmental conditions to obtain high confidence eelgrass mapping included: (1) sun angles below 40°; (2) positive theoretical visibility with Secchi depths >5 m; (3) cloud cover conditions of <10% or >90%; and (4) wind speeds less than 5 km h−1. Additionally, high mapping confidence was achieved for sites with dense, continuous, and homogeneous eelgrass meadows. The results of this analysis will guide implementation of UAS mapping technologies in coastal temperate regions. [ABSTRACT FROM AUTHOR]

The early life history traits of the labrisomid blenny Auchenionchus crinitus (Jenyns, 1842) from subtidal rocky reefs were studied, based on microstructure analysis of sagittae of their pelagic larvae (4.01 mm NL −12.50 mm SL). Ichthyoplankton was collected in shallow (<20 m) nearshore waters off Isla Santa María, Antofagasta, northern Chile every 15 days during austral autumn–winter 2014 (five sampling days). During late May and early June, larval abundance was low (median ± MAD, 39.06 ± 5.08 ind. 100 m−3), increasing significantly during mid-June to early August (110.98 ± 47.66 ind. 100 m−3). Using 354 sagittae, the back-calculated hatch dates indicated the occurrence of three hatching events, two in autumn and one in winter. Hatching occurred mainly during the illuminated phases of the lunar cycle. All three batches had similar estimated larval sizes at hatch (3.2–3.7 mm SL), as well as similar growth rates (0.19–0.22 mm day−1) during the first 30 days of life. During the study period, shallow waters were well mixed, with seawater temperature of 14.73 ± 0.58°C and salinity of 34.84 ± 0.04. This is the first estimation of early life history traits of this cryptobenthic species from rocky reefs of Chile. [ABSTRACT FROM AUTHOR]

Nahirnick, N.K.; Hunter, P.; Costa, M.; Schroeder, S., and Sharma, T., 2019. Benefits and challenges of UAS imagery for eelgrass (Zostera marina) mapping in small estuaries of the Canadian West Coast. Journal of Coastal Research, 35(3), 673–683. Coconut Creek (Florida), ISSN 0749-0208. Seagrasses are a fundamental component of nearshore marine habitats, and as such, concerted effort has been put into developing remote sensing methods to assess the spatial coverage of these important habitats. However, in small coastal bays, traditional aerial or satellite remote sensing can be cost-prohibitive or lack sufficient spatial resolution to detect the small, fringing, and often patchy eelgrass (Zostera marina) meadows. This paper presents a method for collection and processing of unoccupied aerial system (UAS) imagery used to map eelgrass at three small coastal estuaries in the Salish Sea of British Columbia. A low-cost, consumer-grade UAS platform equipped with a GoPro Hero 3+ was used to acquire images with a ground resolution of 2 cm, which were postprocessed using structure-from-motion techniques into georeferenced orthomosaics. A manual classification approach incorporating segmented image objects was used to classify eelgrass on a presence or absence basis, resulting in overall mapping accuracies of 96.3%, 86.5%, and 89.7%, as determined by field validation using kayak videography. The major benefit of this method was fine spatial resolution that allowed for textural discrimination between spectrally similar species. However, eelgrass detection and overall accuracy was found to be highly influenced by the environmental conditions at the time of image acquisition. [ABSTRACT FROM AUTHOR]

Abstract: Simulations of nearshore waves using the Steady-State Spectral Wave (STWAVE) Model with temporally-varying bathymetric boundary conditions were undertaken for a period of 11 months at the U.S. Army Corps of Engineers Field Research Facility in Duck, NC. Five sets of bathymetry were tested, two of which were derived from survey data (one evolving with each monthly bathymetric survey, one static) and three were derived from the depth inversion algorithm, cBathy, using Argus optical imagery data updated every half hour. The standard cBathy half-hourly Kalman filtered product was used along with two modified versions that filter depth estimates during large waves prior to being assimilated by the Kalman filter using an offshore wave height threshold or an optically derived wave breaking threshold to reduce bottom boundary condition errors. Bathymetry derived from the modified Kalman filter methods were first validated using continuous in-situ sonic altimeter data, and were found to improve RMSEs relative to the original cBathy bathymetry from an average of about 0.09 m and about 0.15 m offshore and onshore of the sandbar, respectively. Wave model results over the five bathymetric boundary conditions show that the thresholded cBathy bathymetry performs similarly (and slightly better in places) to simulations using an evolving bathymetry as new measurements are available. The wave height predictions using the static bathymetry were approximately equivalent in performance (if not, slightly better in places) to that of the original cBathy, while the evolving surveyed bathymetry had similar performance to the thresholded cBathy method. Highlights • A video-based depth inversion algorithm, cBathy, was evaluated as a temporally varying bottom boundary condition for nearshore wave modeling. • To improve the quality of remotely sensed bottom boundary estimates, bathymetry was only updated when there was minimal wave breaking in the surfzone. • Nearshore wave height predictions over remotely sensed and surveyed bathymetry had similar skill when compared to field observations over 11 months. • During storm events, wave heights were better predicted when the cBathy bottom boundary condition was held static verses updating every half hour. • The modified cBathy boundary condition reduced over-estimations of wave height predictions compared to the original cBathy boundary condition. [ABSTRACT FROM AUTHOR]

Abstract The construction of breakwaters system in the Nakheel coastal area (west of Alexandria, Egypt) were completed in 2003 to develop a secure area for swimmers and recreational activities. The main objective of this work is to assess the influences of this coastal defensive structure on the distribution of benthic foraminiferal communities. Thirty-two near-shore sediments samples were collected in winter and summer (2011) to investigate the benthic foraminifera and sedimentological (grain size, total carbonate and total organic carbon) characteristics. The epiphytic species dominated foraminiferal assemblages in both seasons. The accumulation of massive quantity of seaweeds and macroalgae in addition to hydrodynamics in the sheltered leeside area are direct impacts of the breakwaters system. In turn, these biotic and physical variables are responsible for cross-shore transport of benthic forams to near-shore area and their distribution along-shore. Two mechanisms are suggested for forams' transport to the near-shore area; the biotic mechanism during winter via attaching seaweeds and macroalgae, and the physical mechanism in which the foraminifera are transferred as bed-load through cross-shore transportation, particularly in summer. This study suggests that the breakwaters system in addition to weather conditions govern winter-summer and spatial variations in foraminiferal assemblages in the protected Nakheel near-shore coastal area. [ABSTRACT FROM AUTHOR]

Abstract Reflected waves account for a significant part of the nearshore energy budget and influence incoming waves, nearshore circulation and sediment transport. The use of swash parameters to estimate wave reflection is investigated at three different beaches ranging from highly reflective to dissipative. It is observed that it is essential to account for swash processes when estimating reflection, in particular at intermediate and reflective beaches with a steep beachface. Our results show that runup asymmetry in uprush/backwash can be used as a proxy for dissipation in the swash zone: larger asymmetry values indicating greater dissipation. In our dataset, a reflection predictor based on runup asymmetry has better skill in comparison to empirical predictors based on surf similarity, because runup is a process that integrates both surf and swash zone wave transformation. Runup asymmetry behaves as a swash similarity parameter and reflects an equilibrium between swash period, slope and dissipation. Highlights • Link between swash parameters and wave reflection investigated at three different beaches. • Asymmetry in uprush/backwash can be considered a proxy for swash dissipation. • Evidence of equilibrium between runup asymmetry, period and slope. [ABSTRACT FROM AUTHOR]

Abstract Over the last decades, plastic debris has been identified and quantified in the marine environment. Coastal and riverine input have been recognized as sources of plastic debris, whereas oceanic gyres and sediments are understood to be sinks. However, we have a limited understanding of the fate of plastic debris in the nearshore environment. To investigate the movement and distribution of plastic debris in the nearshore environment, we collected samples at three distinct locations: below the high tide line, the turbulent zone created by the combination of breaking wave and backflush (defined as the boundary), and the outer nearshore. We estimated the abundance and physical characteristics (e.g. density, hardness, etc.) of macroplastic and microplastics. Four times and 15 times more macroplastics and microplastics are observed, respectively, at the boundary than in the outer nearshore waters, which suggests an accumulation driven by the physical properties of the plastic particles such as density, buoyancy and surface area. We further report that highly energetic conditions characteristic of the boundary area promote the long-term suspension and/or degradation of low density, highly buoyant or large surface area plastic debris, leading to their preferential accumulation at the boundary. Contrastingly, denser and low surface area plastic pieces were transported to the outer nearshore. These results emphasize the role of selective plastic movement at the nearshore driven by physical properties, but also by the combined effects of several hydrodynamics forces like wave action, wind or tide in the resuspension, as well as degradation and transport of plastic debris out of the nearshore environment. Graphical abstract Image 1 Highlights • Breaking wave area has higher abundance of plastic litters than nearshore waters. • Wave dynamics impact the composition of plastic litter. • EP macroplastics are more abundant on the beach but EP microplastics are more abundant at the boundary. • Harder and denser plastic are transported offshore. A higher abundance of plastic litter has been found in the breaking wave area of nearshore marine environments. This is attributed to wave dynamics responsible for selective transport of plastic litter based on their physical characteristics. [ABSTRACT FROM AUTHOR]

In the present study monthly observation (January 2011 to January 2012) of wave measurements and sediment samples are considered for multivariate statistical analysis. The CCA plots revealed that heavy mineral concentration in the tidal region proportional to the breaker wave height, longshore current velocity and surf zone width, while concentration in berm region proportional to the wave period. The distant projection of backshore samples revealed that heavy mineral distribution controlled by the aeolian process. Moreover, results of 3D scatter plot between sediment characteristics and heavy mineral deposits confirm this correlation on a temporal scale. The overall result implies that the monsoonal wave process does not affect the heavy mineral distribution, but influencing the quantity of deposits. [ABSTRACT FROM AUTHOR]

The installation of wave energy converter (WEC) arrays near the coast can have significant impacts on sediment dynamics and coastal morphodynamics. However, methodologies for quantifying these impacts and strategies to minimize them are still in need of development. In this study, we assessed the coastal response to a WEC array on the La Guajira coast in the Colombian Caribbean using a two-step numerical strategy. We used the Delft-3D model to estimate the wave field, which was then transferred to the XBeach model to compute morphological changes. This modelling strategy was applied to three WEC array layouts and compared the morphological responses in terms of the distance and relative orientation of the WEC array to the coast. The results showed that the impact of the simulated WEC array on the beach response varied significantly depending on its distance from the coast, the configuration of the array, and its orientation. These findings highlight the need for further research to develop effective strategies for minimizing coastal erosion impacts on coastal ecosystems through innovative alternatives. Developing such strategies will be crucial to ensure the sustainable implementation of WEC arrays and other renewable energy technologies near the coast. • WECs have the capability to convert wave energy into useable electricity efficiently. • Coastal communities can benefit from renewable energy and coastal protection. • Delft 3 d and XBeach models are useful for estimating energy potential and beach erosion. • WECs array configuration is a key element in energy efficiency and wave reduction. [ABSTRACT FROM AUTHOR]

Accurate wave predictions are crucial for many marine-related activities, including offshore operations, navigation, and marine renewable energy. To improve the forecast performance, this study presents a data assimilation system that utilizes the WAVEWATCH III wave model and the local Ensemble Optimal Interpolation scheme to assimilate significant wave heights data from HY-2B altimeter in the China Seas. The effects of assimilation are analyzed in both coastal and offshore regions at different distances from assimilated satellite data points during a forecast period. The results show that systematic bias in wave forecasting for both offshore and nearshore locations can be effectively reduced through the use of data assimilation, with localization employed to minimize the influence of random errors. Nearshore forecasting benefits from assimilation to a greater extent than offshore forecasting, with a more enduring improvement observed. Additionally, the decline in forecast improvement with increasing distance from assimilated data highlights the necessity of assimilating a greater quantity of observational satellite data. Furthermore, careful consideration should be given to the size of the ensemble when using a specific localization radius, as the improvement in skill may stagnate with larger ensembles. Finally, assimilating additional nearshore satellite data does not negatively impact the predictive precision. [ABSTRACT FROM AUTHOR]

In this paper, a new exponential formed vertical distribution of nearshore flow velocity is constructed, which is simpler in form and more suitable for engineering application. The physical meaning of the new formula is more specific than that of Soulsby. Compared with those logarithmic formed ones, the new one does not need the maximum velocity and only needs the mean velocity in vertical, which gives it better engineering practicability. Apply the new formula to Jiangsu coastal area and compare the results with that of Soulsby whose results show the new formula agrees better with the measured flow velocity, which reasonably reflects the basic principles of vertical distribution of flow velocity.

The need for quantitative assessments at a large spatial scale (103 km) and over time horizons of the order 101 to 102 years have been reinforced by the 2019 Special Report on the Ocean and Cryosphere in a Changing Climate, which concluded that adaptation to a sea-level rise will be needed no matter what emission scenario is followed. Here, we used a simple geometrical analysis of the backshore topography to assess the likely response of any wave-dominated coastline to a sea-level rise, and we applied it along the entire Great Britain (GB) coastline, which is ca. 17,820 km long. We illustrated how the backshore geometry can be linked to the shoreline response (rate of change and net response: erosion or accretion) to a sea-level rise by using a generalized shoreline Exner equation, which includes the effect of the backshore slope and differences in sediment fractions within the nearshore. To apply this to the whole of GB, we developed an automated delineation approach to extract the main geometrical attributes. Our analysis suggests that 71% of the coast of GB is best described as gentle coast, including estuarine coastline or open coasts where back-barrier beaches can form. The remaining 29% is best described as cliff-type coastlines, for which the majority (57%) of the backshore slope values are negative, suggesting that a non-equilibrium trajectory will most likely be followed as a response to a rise in sea level. For the remaining 43% of the cliffed coast, we have provided regional statistics showing where the potential sinks and sources of sediment are likely to be.

The breaking wave height is a crucial parameter for coastal studies but direct measurements constitute a difficult task due to logistical and technical constraints. This paper presents two new practical methods for estimating the breaking wave height from digital images collected by shore-based video monitoring systems. Both methods use time-exposure (Timex) images and exploit the cross-shore length ( L H s ) of the typical time-averaged signature of breaking wave foam. The first method ( H s b , v ) combines L H s and a series of video-derived parameters with the beach profile elevation to obtain the breaking wave height through an empirical formulation. The second method ( H s b , v 24 ) is based on the empirical finding that L H s can be associated with the local water depth at breaking, thus it can be used to estimate the breaking wave height without the requirement of local bathymetry. Both methods were applied and verified against field data collected at the Portuguese Atlantic coast over two days using video acquired by an online-streaming surfcam. Furthermore, H s b , v 24 was applied on coastal images acquired at four additional field sites during distinct hydrodynamic conditions, and the results were compared to a series of different wave sources. Achievements suggest that H s b , v method represents a good alternative to numerical hydrodynamic modeling when local bathymetry is available. In fact, the differences against modeled breaking wave height, ranging from 1 to 3 m at the case study, returned a root-mean-square-error of 0.2 m. The H s b , v 24 method, when applied on video data collected at five sites, assessed a normalized root-mean-square-error of 18% on average, for dataset of about 900 records and breaking wave height ranging between 0.1 and 3.8 m. These differences demonstrate the potential of H s b , v 24 in estimating breaking wave height merely using Timex images, with the main advantage of not requiring the beach profile. Both methods can be easily implemented as cost-effective tools for hydrodynamic applications in the operational coastal video systems worldwide. In addition, the methods have the potential to be coupled to the numerous other Timex applications for morphodynamic studies.

We introduce a model for the dynamics of oil in suspension, appropriate for shallow waters, including the nearshore environment. This model is capable of oil mass conservation and does so by evolving the oil on the sea surface as well as the oil in the subsurface. The shallower portion of the continental shelf poses compounding unique modeling challenges. Many of these relate to the complex nature of advection and dispersion of oil in an environment in which wind, waves, as well as currents all play a role, as does the complex bathymetry and the nearshore geography. In this study we present an overview of the model as well as derive the most fundamental of processes, namely, the shallow water advectiion and dispersion processes. With regard to this basic transport, we superate several fundamental challenges associated with creating a transport model for oil and other buoyant pollutants, capable of capturing the dynamics at the large spatio-temporal scales demanded by environmental and hazard mitigation studies. Some of the strategies are related to dimension reduction and upscaling, and leave discussion of these to companion papers. Here we focus on wave-filtering, ensemble and depth-averaging. Integral to the model is the proposal of an ocean dynamics model that is consistent with the transport. This ocean dynamics model is detailed here. The ocean/oil transport model is applied to a couple of physically-inspired oil-spill problems in demonstrate its specialized capabilities.

Dry weather pollution sources cause coastal water quality problems that are not accounted for in existing beach advisory metrics. A 1D wave-driven advection and loss model was developed for a 30 km nearshore domain spanning the United States/Mexico border region. Bathymetric nonuniformities, such as the inlet and shoal near the Tijuana River estuary mouth, were neglected. Nearshore alongshore velocities were estimated by using wave properties at an offshore location. The 1D model was evaluated using the hourly output of a 3D regional hydrodynamic model. The 1D model had high skill in reproducing the spatially averaged alongshore velocities from the 3D model. The 1D and 3D models agreed on tracer exceedance or nonexceedance above a human illness probability threshold for 87% of model time steps. 1D model tracer was well-correlated with targeted water samples tested for DNA-based human fecal indicators. This demonstrates that a simple, computationally fast, 1D nearshore wave-driven advection model can reproduce nearshore tracer evolution from a 3D model over a range of wave conditions ignoring bathymetric nonuniformities at this site and may be applicable to other locations.

The Department of Environment and Natural Resources, and the United Nations Educational, Scientific and Cultural Organization (UNESCO) classified the bodies of water in Davao as Class SB for seawater environment along the Davao Gulf and Class B or recreational water on the downstream area of the Davao River. Under these classifications, both bodies of water can be used by the public for recreational and other important activities. However, with the development in the City, the quality of these bodies of water is threatened by and affected with the accumulation of various pollutants particularly heavy metals. In order to assess the current heavy metal pollution in the aquatic environments, scientific investigation was conducted to determine the concentrations of the following heavy metals: Cadmium (Cd), Lead (Pb), Manganese (Mn), Iron (Fe), Zinc (Zn) and Copper (Cu) in two environmental sampling units, the typical estuarine (downstream) and near shore environments along Davao gulf. Surface water and sediments were sampled in these sites. Results show that the surface water environment contained substantial amount of Cd, Pb, Mn, Fe and Zn. Of these heavy metals, the concentrations of Cd and Pb were found to be higher than the maximum allowable limits for both fresh and marine water. In addition, significant enrichments of Cd, Cu, Fe, Mn and Zn were detected on the surface sediments of the downstream environment. Results revealed that except for the Pb level, the mean concentrations of most heavy metal (Cd, Cu and Zn) in the surface sediments were substantially higher compared to the threshold effects limit. The findings demonstrate the accumulations of heavy metals in the aquatic resources which call for immediate review of the current classifications of the bodies of water in the region. [ABSTRACT FROM AUTHOR]

Abstract Mariculture activities including enclosure, raft and cage cultures employ a variety of plastic gear such as fishing nets, buoyant material and net cages. The plastic gear poses a potential source of microplastics to the coastal environment, but relevant data on the impacts of mariculture are still limited. To this end, a semi-enclosed narrow bay (i.e., Xiangshan Bay, China) with a long-term mariculture history was investigated to assess how mariculture activities affect microplastics in seawater and sediment. The results indicated that mariculture-derived microplastics accounted for approximately 55.7% and 36.8% of the microplastics in seawater and sediment, respectively. The average microplastic abundances of seawater and sediment were 8.9 ± 4.7 (mean ± SD, n = 18) items/m3 seawater and 1739 ± 2153 (n = 18) items/kg sediment, respectively. The types of mariculture-derived microplastics included polyethylene (PE) foam, PE nets, PE film, polypropylene (PP) rope, polystyrene (PS) foam and rubber. PE foam had the highest proportion (38.6%) in the seawater samples. High usage rates and the porous structure of PE foam led to the high abundance. The average microplastic sizes of seawater and sediment are 1.54 ± 1.53 mm and 1.33 ± 1.69 mm, respectively. The spatial variations in the abundance and size of microplastics implied that the mariculture-derived microplastics in Xiangshan Bay were transported along the Bay to the open sea. The results of this study indicate that mariculture activity can be a significant source of microplastics. Further research is required to investigate how the high microplastic abundance in mariculture zone affects marine organisms, especially cultured seafood. Graphical abstract Image 1 Highlights • The surface seawater of Xiangshan Bay had 8.9 ± 4.7 (n = 18) microplastics per m3 seawater. • The sediments of Xiangshan Bay had 1739 ± 2153 (n = 18) microplastics per kg sediment. • Approximately 55.7% and 36.8% of the seawater and sediment microplastics were from mariculture, respectively. • The porous structure of PE foam led to high fragmentation. • Mariculture-derived microplastics in Xiangshan Bay were transported to the open sea. Results of this work imply that the long-term intensive mariculture activities have caused a significant microplastic issue for Xiangshan Bay, China. [ABSTRACT FROM AUTHOR]

Abstract Coastal ecosystem goods and services (EGS) have steadily gained traction in the scientific literature over the last few decades, providing a wealth of information about underlying coastal habitat dependencies. This meta-analysis summarizes relationships between coastal habitats and final ecosystem goods and services (FEGS) users. Through a "weight of evidence" approach synthesizing information from published literature, we assessed habitat classes most relevant to coastal users. Approximately 2800 coastal EGS journal articles were identified by online search engines, of which 16% addressed linkages between specific coastal habitats and FEGS users, and were retained for subsequent analysis. Recreational (83%) and industrial (35%) users were most cited in literature, with experiential-users/hikers and commercial fishermen most prominent in each category, respectively. Recreational users were linked to the widest diversity of coastal habitat subclasses (i.e., 22 of 26). Whereas, mangroves and emergent wetlands were most relevant for property owners. We urge EGS studies to continue surveying local users and identifying habitat dependencies, as these steps are important precursors for developing appropriate coastal FEGS metrics and facilitating local valuation. In addition, understanding how habitats contribute to human well-being may assist communities in prioritizing restoration and evaluating development scenarios in the context of future ecosystem service delivery. Graphical abstract Image 1 Highlights • Industry and recreation dominated final coastal ecosystem goods/services literature. • Recreational users were linked to the widest array of coastal habitats. • Evidence linking users to estuarine waters was most prominent. • The relevance of coastal habitats to intermediate services was cited often. • Improve future ecosystem goods and services research by adding local user information. [ABSTRACT FROM AUTHOR]

Abstract Sediment samples were collected from nearshore, tributary and beach environments within and surrounding the northern part of Lake Erie, Ontario to determine the concentrations and distribution of microplastics. Following density separation and microscopic analysis of 29 samples, a total of 1178 microplastic particles were identified. Thirteen nearshore samples contained 0–391 microplastic particles per kg dry weight sediment (kg−1), whereas 4 tributary samples contained 10–462 kg−1 and 12 beach samples contained 50–146 kg−1. The highest concentrations of nearshore microplastics were from near the mouths of the Detroit River in the western basin and the Grand River in the eastern basin, reflecting an urban influence. The highest microplastic concentrations in beach samples were determined from Rondeau Beach in the central basin where geomorphology affects plastics concentration. The Welland Canal sample in the eastern basin contained the greatest concentration of microplastics of the tributary samples, which is consistent with high population density and shipping traffic. The overall abundance of microplastic in northern Lake Erie nearshore, tributary and beach samples is 6 times lower than in sediment sampled from northern Lake Ontario. The nearshore and beach sample results potentially reflect the transport patterns of floating plastics modeled for Lake Erie, which predict that the majority of plastic particles entering the lake are transported to southern shoreline regions rather than northern areas. [ABSTRACT FROM AUTHOR]

Although chondrichthyans are conspicuously present in shallow waters, many ecological aspects of neritic species in the Humboldt Current System remain unknown. This study provides a first assessment of the diet of seven commercially exploited and understudied sympatric chondrichthyans inhabiting nearshore habitats off the central coast of Peru: four stingrays (Hypanus dipterurus, Myliobatis peruvianus, M. chilensis, and Urotrygon chilensis), a guitarfish (Pseudobatos planiceps), a smooth-hound shark (Mustelus mento), and a chimaera (Callorhinchus callorynchus). A total of 166 stomachs were examined between 2012 and 2015 and prey items were pooled for the total of years for analysis. Although our analysis did not account for inter seasons variability, our results suggest diet partitioning among species, except for the stingrays’ group. A diet based on soft-bottom polychaetes and fish was shared by H. dipterurus, M. peruvianus, and M. chilensis, while soft-bottom polychaetes and crabs were more important in U. chilensis. The smooth-hound shark and guitarfish exhibited a diet dominated by crabs, and the chimaera consumed mainly hard-bottom mollusks. Foraging habitat estimations distinguished two main habitats of association: Benthic, including the stingray U. chilensis, the chimaera, and the smooth-hound shark; and benthic-demersal, including the guitarfish, and the rest of stingrays. A pattern of feeding specialization was observed for H. dipterurus, P. planiceps, and C. callorynchus. Preliminary trophic level estimations based on diet composition placed these species as secondary consumers. Intraspecific dietary variation was assessed for P. planiceps and H. dipterurus as their sampled sizes allowed meaningful comparisons. The diet of P. planiceps varied from small to large sizes but not for H. dipterurus. No differences were detected on diet composition between males and females in either species. Despite the limited temporal resolution, this study provides the first insights of chondrichthyans predatory activity, suggesting diet partitioning among the species of this assemblage in a nearshore habitat of the central coast of Peru. Enhancing the temporal resolution of this type of studies would improve our knowledge on trophic functioning in the Humboldt Current ecosystem. [ABSTRACT FROM AUTHOR]

The Late Permian extinction interval is in many marine locations characterized by the development of anoxic conditions. The Finnmark Platform is one of few exceptions, as sedimentological and palynofacies evidence indicate oxygenated conditions throughout the event. Changes in acritarch assemblages and morphology were studied in order to better understand the link between acritarchs and environmental conditions. The main taxa are of Micrhystridium , Baltisphaeridium and leiospheres, while Veryhachium and the prasinophytes Cymatiosphaera and Tasmanites were present in low abundances. Increased concentrations of acritarchs, particularly Micrhystridium , show that the environmental changes at the start of the extinction event may have resulted in enhanced marine productivity. A shift from Micrhystridium/Baltisphaeridium dominance before and during the extinction event, to leiosphere-dominance after the extinction event, indicates a shift towards a more inshore environment. The new data are compared with published Late Permian acritarch records from East Greenland, China and Pakistan. A striking difference between the East Greenland and Finnmark Platform, which are both expanded Upper Permian/Lower Triassic sections, is that the acritarch record from Greenland shows a strong decrease in process length of the acritarch Micrhystridium . Together with a change in the acritarch assemblage, this change in morphology was interpreted to represent a decrease in salinity at the site, resulting from increased run-off. The differences between the East Greenland and the Finnmark records are likely due to their palaeogeographical settings, as the East Greenland section was located in a narrow and elongated basin which was likely more sensitive to evaporation and run-off changes than the Finnmark Platform. [ABSTRACT FROM AUTHOR]