Le Mouël, J.-L.; Lopes, F., and Courtillot, V., 2021. Sea-level change at the Brest (France) tide gauge and the Markowitz component of Earth's rotation. Journal of Coastal Research, 37(4), 683–690. Coconut Creek (Florida), ISSN 0749-0208.

This paper centers on singular spectrum analysis (SSA) of variations in sea level in Brest (France) and in Earth's axis of rotation. Brest tide gauge data (recording the Brest sea level [BSL]) are available from 1807 onward. The main features of the BSL curve are common to most stations in the Northern Hemisphere; hence, the Brest curve has recorded a gross Earth datum. Pole positions (coordinate m₂), another gross Earth datum, are from the International Earth Rotation and Reference System Service (1845–2019). The first SSA components of both series, i.e. the trends, are similar, with a major acceleration event near 1900 and sea level lagging pole motion by ∼5 to 10 years. SSA components with periods of 1, 5.4, and ∼11 years are common to the two series. An important feature is a 0.5-year component that is present in sea level but absent from pole motion. The remarkable similarity of the two trends and their phase lag suggests a causal relationship opposite the one that is generally accepted.

Kassem, H.; Sutherland, T.F., and Amos, C.L., 2021. Hydrodynamic controls on the particle size of resuspended sediment from sandy and muddy substrates in British Columbia, Canada. Journal of Coastal Research, 37(4), 691–707. Coconut Creek (Florida), ISSN 0749-0208.

A benthic annular flume, Sea Carousel, was deployed at both sand-dominated (Baynes Sound) and mud-dominated (Carrie Bay) stations in British Columbia, Canada, to examine the character of near-bed flow over these contrasting bottom types and its control on particle size of resuspended sediment. An assessment has also been made of the turbidity-induced drag reduction due to suspension of bottom sediments. The median sizes of suspended material from the sandy sites have been compared with the well-known Rouse theory, whereas the aggregates resuspended from muddy stations were scaled with the energy dissipation rate (ε) determined from high-frequency three-dimensional flow measures in the flume. There was no evidence in the turbulence spectra in the Sea Carousel of energy inputs in the paddle and lid rotational frequencies, and a f^–5/3 slope for f > 2 Hz in turbulent transitional flows was evident. The bed roughness length of sandy sites was Reynolds-number dependent but was asymptotic to a constant value of 2 mm at high flows. This equated to a dimensionless drag coefficient at 1 m above bed of a constant, 3 × 10^–3 (also at high Reynolds numbers), which agrees well with values reported in the literature. The median size of suspended sand (from the sandy sites) and equivalent still water settling rate (w_s) scaled with the friction velocity (u^*) in the form w_s/u^* = D^*/8. The median size of resuspended aggregates (d_f) scaled inversely with dissipation (ε) in the form d_f = 5 × 10^–6ε^–0.24m, which is close to the relationship found in the literature.

Xu, Y.; Liao, B.; Jiang, Z.; Xin, K.; Xiong, Y., and Zhang, Y., 2021. Examining the differences between invasive Sonneratia apetala and native Kandelia obovata for mangrove restoration: Soil organic carbon, nitrogen, and phosphorus content and pools. Journal of Coastal Research, 37(4), 708–715. Coconut Creek (Florida), ISSN 0749-0208.

Mangroves play an important role in enhancing soil organic carbon (SOC) and nutrient pools. The exotic Sonneratia apetala is widely used for the restoration of mangroves in China because of its fast growth. However, it is not clear whether S. apetala increases SOC, nitrogen, and phosphorus pools compared with the native mangrove species. Thus, the aims of this study were to determine whether Kandelia obovata and the fast-growing mangrove species S. apetala have advantages with regard to the SOC, nitrogen, and phosphorus content and pools and whether restored mangroves have SOC, nitrogen, and phosphorus content and pools similar to those of original mangroves. Four sites in the Qi'ao-Dangan Provincial Nature Reserve were selected: a 15-year-old planted S. apetala forest, a 15-year-old planted K. obovata forest, a native K. obovata forest, and an unvegetated mudflat. The content and pools of organic carbon, nitrogen, and phosphorus in the soil were compared. Compared with mudflats, the content and pools of SOC, nitrogen, and phosphorus were significantly increased by planting S. apetala. However, compared with the 15-year-old planted K. obovata, the fast-growing S. apetala showed no advantage. The content and pools of SOC and nitrogen in the 15-year-old planted S. apetala site were lower than those of native K. obovata forests. It is recommended that more native mangrove species be used for future mangrove restoration to increase the content and pools of SOC, nitrogen, and phosphorus.

Wang, R.; Zhu, Z.; Zhu, W.; Fu, X., and Xing, S., 2021. A dynamic marine oil spill prediction model based on deep learning. Journal of Coastal Research, 37(4), 716–725. Coconut Creek (Florida), ISSN 0749-0208.

Water pollution resulting from shipborne oil spills has caused tremendous damage to local marine ecology and has led to huge property losses. By establishing a multi-angle monitoring and early-warning mechanism, the oil spill's trajectory to a large extent can be effectively predicted, and thereby the accompanying economic losses can be reduced. In this study, real-time processing is performed on an oil spill monitoring video frame to analyze the characteristics of the spilled oil, such as the edge contour features, diffusion rate, centroid, area, etc. An initial system model and an oil spill behavior monitoring model were established based on the previously mentioned characteristics. A long short-term memory network in a recurrent neural network was introduced to deal with the memory information to obtain the connection between features and influencing factors. The spatial variable distribution of a dynamic grid reference system, as a substitution of the traditional original data sequence, was used as the system input. The result shows that the model has good stability and can provide a reliable interactive prediction; the result is especially significant given the vigorous exploitation of petroleum resources and the rapid development of maritime transportation in today's global economy. The auxiliary oil spill early-warning system investigated in this paper provides a scientific basis for targeted strategic oil spill emergency planning.

Custado, M.J.G. and David, C.P.C., 2021. Assessing the spatial and temporal relationship between coastal runoff and chlorophyll-a in the Philippines using gridded datasets. Journal of Coastal Research, 37(4), 726–736. Coconut Creek (Florida), ISSN 0749-0208.

Publicly available gridded datasets were used in examining the relationship between long-term temporal patterns in runoff rates and chlorophyll-a within the coastal areas of the Philippines. Temporal plots generated from remotely sensed chlorophyll-a data and runoff from the Global Runoff Reconstruction dataset illustrated variabilities in seasonal patterns across coastal segments and climate types. The linear correlation analysis performed on the datasets revealed a characteristic distribution of negative coefficients within the internal seas of the archipelago and positive coefficients in open coasts and embayments. Riverine-influenced sites with positive correlation coefficients (r = 0.33–0.62, p < 0.00001) were mostly associated with delivery of excess nutrients from land-use activities. The distribution of these coefficients was demonstrated to be affected by the physical nature of the coast. Moreover, seasonal changes in total suspended solids adjacent to a river discharge site were discussed, demonstrating how high sediment load can dampen productivity because of limited light penetration in marine waters. The analysis of publicly available datasets in this study provided assessments that can be used to complement coastal management efforts, particularly in the context of increasing anthropogenic stress and climate change.

Xu, H.; Li, D.; Hou, X.; Yu, X.; Liu, Y.; Li, X.; Li, B.; Chen, L.; Wang, X., and Xia, S., 2021. Home range and habitat disturbance identification for a vulnerable shorebird species (Larus saundersi) in the Yellow River Delta, China. Journal of Coastal Research, 37(4), 737–748. Coconut Creek (Florida), ISSN 0749-0208.

Understanding the home range of animal species can be helpful to biodiversity and habitat conservation. Saunders's Gull (Larus saundersi), one of the vulnerable birds in the world, has become an important indicator species to measure the quality of ecological environment in the coastal wetlands of the Yellow River Delta. Information about habitat selection of the species has so far been mainly from field survey. In view of the successful application of satellite tracking in animal ecology, two individual birds were tagged for home range identification and habitat disturbance analysis. The gull's home range was confirmed using the Brownian bridge movement model. Habitat disturbances information from anthropogenic activities was analyzed by kernel density estimation as well as buffer zone analysis. Considering the gregariousness of the shorebird, the tracking sample data, though limited, can reflect the species' habitat selection to a certain extent. The results showed that (1) the Saunders's Gull's main home range was located in the northern and eastern coastal areas of Dongying city, the seashore area at the border of Binzhou with Dongying and Cangzhou city, and the Nanpu wetland of Tangshan city; and (2) human activity had a substantial effect on the home range selection, for example, mariculture was an important part of its home range, the Saunders's Gull exhibited an approach–avoidance behavior to wind turbines and oil wells, and activity time varied with different distances to the road. The study provides insights into the behavior of the shorebird and is of great significance to sustainable development of the human–environment relationship in the Yellow River Delta.

Xiao, Y.; Jia, H.; Guan, D.; Liang, D.; Yuan, S., and Tang, H., 2021. Modeling clear-water scour around the high-rise structure foundations (HRSF) of offshore wind farms. Journal of Coastal Research, 37(4), 749–760. Coconut Creek (Florida), ISSN 0749-0208.

The high-rise structure foundation (HRSF) has been used in building the Donghai offshore wind farm in Shanghai, China. So far, few published studies can be found on the local scour around an HRSF. This study presents the results of a physical modeling investigation of the clear-water scour around two typical HRSF models consisting of eight piles and 10 piles, respectively. In the study, the flume bed was covered with uniform noncohesive sediment and the incoming flow was steady. The effects of the alignment angle of the HRSF, water depth, and relative sediment size on the equilibrium scour depth were analyzed. Results showed that the maximum scour depth always occurred around the middle piles on the shoulders of the HRSF. The alignment angle of the HRSF had little influence on the final equilibrium scour depth. For permeable multipile foundations, the scour depth increased when the water depth increased within the range of the testing conditions, which indicates a similar trend between a multipile foundation and a monopile. An empirical formula is proposed for estimating the equilibrium scour depth.

Ai, X. and Zhao, L., 2021. Comprehensive evaluation of power grid planning in coastal regions of China in the context of power internet of things (PIoT). Journal of Coastal Research, 37(4), 761–770. Coconut Creek (Florida), ISSN 0749-0208.

With the proposal and promotion of the concept “New Infrastructure Construction” in China, the construction of Power Internet of Things (PIoT) has become one major task of China's power grid development. Coastal regions have the characteristics of developed economy, high electricity demand, and variable climate, which are the focus of power grid construction. Hence, the construction of PIoT has put forward new requirements for power grid planning in coastal regions, and a comprehensive evaluation of power grid planning must be performed. However, the existing power grid evaluation index system cannot meet the comprehensive requirements of PIoT. Moreover, the current comprehensive evaluation method cannot solve problems on similar correlations and cannot perform dynamic prediction. This study proposes a comprehensive evaluation method for power grid planning in coastal regions in the context of PIoT. This method uses the requirements for developing PIoT as a criterion in constructing a seven-dimensional index system with 30 indexes. It also adopts the matter element analysis model, which can obtain more accurate correlations and change the evaluation method from static to dynamic. Taking a coastal province as an example, this paper performs comprehensive evaluation of current situation, development trend, and weak links of power grids and has satisfactory evaluation performance and prediction effect. It also proved that this method can clarify key points for improving and establishing development policies and provides guiding significance for power grid planning in coastal regions.

Payne, A.R.; Burdick, D.M.; Moore, G.E., and Wigand, C., 2021. Short-term effects of thin-layer sand placement on salt marsh grasses: A marsh organ field experiment. Journal of Coastal Research, 37(4), 771–778. Coconut Creek (Florida), ISSN 0749-0208.

Salt marshes can build in elevation with sea-level rise through accumulation of inorganic sediment and organic matter, but marshes worldwide are under threat of drowning due to rapid rates of sea-level rise that outpace natural marsh building rates. The application of a thin layer of sediment to the marsh surface (thin-layer placement [TLP]) is a tool to build elevation and decrease flooding stress, but its effects on marsh plants are understudied, especially in New England. In a novel application of a marsh organ experiment (i.e. rows of pots at different elevations), the addition of 10 cm of sand to pots planted with Spartina alterniflora and Spartina patens resulted in fewer stems than controls for S. patens but not S. alterniflora after 2 months. However, total biomass and root mass were not significantly impacted for either species, suggesting plants will fully recover from TLP over longer timescales. Effects of TLP on biomass and stem density did not vary significantly by elevation. Although long-term research is still needed, short-term equivalency in biomass between TLP treatments and controls suggests TLP of 10 cm is a promising strategy to enhance the ability of marshes to build vertically as sea level rises in New England.

Hu, X.; Wang, Y.; Wu, F., and Huang, A., 2021. Using a new channel estimation algorithm to improve underwater acoustic communication with multiple receivers. Journal of Coastal Research, 37(4), 779–783. Coconut Creek (Florida), ISSN 0749-0208.

Underwater acoustic (UWA) communication with multiple receivers has been developed for underwater wireless data transmission, because the receiving array can improve the reliability of the system by using spatial diversity. In this paper, a channel estimation algorithm is proposed that fully uses UWA channel sparsity for single-input, multiple-output (SIMO) communication. The proposed algorithm integrates L₀ norm into the cost function of the improved proportionate normalized least-mean-square (IPNLMS) algorithm based on L₀ norm. The performance of the L₀ norm–constrained IPNLMS, IPNLMS based on L₀ norm, and the proposed algorithm is studied in terms of normalized misalignment for SIMO UWA channel estimation. In addition, the influence of the number of receivers on channel estimation accuracy is analyzed. Finally, the numerical simulation results demonstrate the superiority of the proposed algorithm in terms of robustness, which achieves the lower normalized misalignment than the other two algorithms in a shallow-water acoustic channel estimation.

Jumprom, N.; Rodcharoen, E., and Wichachucherd, B., 2021. The physicochemical properties of sediment and ground cover for a secondary mangrove system in Thailand. Journal of Coastal Research, 37(4), 784–792. Coconut Creek (Florida), ISSN 0749-0208.

Mangrove forests serve various positive aspects for human use and accumulate sediment and filter impurities from the land and sea. In this study, the investigation was performed on the year-round changes in the physicochemical characteristics of sediment and the percentage of cover of the bottom in a secondary mangrove where public-access mangrove areas and the mouth of the Mae Klong River to the sea at Samut Songkhram province, Thailand. Organic carbon (OC), organic matter (OM), bulk density, and grain size were measured in the sediment samples. The percentage of cover and litter dry weight were estimated using 50-cm² quadrats. Conductivity, total dissolved solids, pH, and salinity were measured from the sediment. Air and water temperatures were recorded. The study site was divided into upper-, middle-, and low-tide levels. The results showed that tidal levels and months had significantly different (p < 0.05) influences on all of the factors examined. The percentage of OC and percentage of OM increased continuously at the upper levels but were low at the middle and lower levels. The bulk density, however, was low in value in the low-tide zone. In addition to the percentage of cover, the percentage of soil and percentage of aerial root were found mostly in the middle to low zones. The percentage of garbage waste and percentage of litter were not different at different levels, and nor was the dry weight, throughout the period of study. The grain size in each month was classified as clay type, pH, conductivity, total dissolved solid, and salinity obtained from sediment varied significantly (p < 0.05) among levels and months. In summary, the upper level is influenced by the terrestrial runoff. Environmental factors such as climate and geography affect the sediment quality at the middle and lower levels.

Ji, Y. and Yin, Y., 2021. Water quality maintenance approaches and on-site monitoring results of an artificial bathing beach. Journal of Coastal Research, 37(4), 793–799. Coconut Creek (Florida), ISSN 0749-0208.

The construction of artificial beaches on the muddy coasts involves water purification and long-term maintenance. In the paper, based on the investigation of tidal current, sediment distribution, water quality, and background creatures, a technical scheme of “building submerged breakwater enclosure and accelerating sediment deposition” to form a transparent water body and a long-term water quality maintenance scheme of “diversion, drainage, and self-purification of ecology” are proposed. Through sand precipitation test, water exchange feasibility, and facility scale demonstration, biological purification measures research and on-site practice, as well as long-term water quality monitoring and analysis, the conclusions are as follows: (1) The construction of submerged breakwater for water enclosure promotes the sediment deposition process. The experiment results indicate that after two-day static settlement, 93% of the suspension is precipitated and the concentration of total phosphorus decreased by more than 70%. (2) Water from artificial beaches can be diverted by harnessing tide or pumping facilities. The scale of the pump station and sluice should be determined according to the filling or drainage capability of water in a tidal cycle. (3) The ecological self-purification should be established on the basis of background investigation. The aquatic animals, such as fish, shrimp, crab, shell, and algae m (4) The water quality tends to deteriorate and changes with seasons with the increase of tourists. Finally, it is suggested renovating the current water diversion system, enhancing the monitoring of ecosystem, limiting the number of tourists in summer and increasing the frequency of water exchange.

Duan, L.; Xing, L.; Wang, D.; Fan, M., and Wang, P., 2021. Numerical investigation of wave-induced uplift force exerted onto a shallowly buried pipeline using a two-dimensional fully coupled model for wave-seabed-structure interaction. Journal of Coastal Research, 37(4), 800–812. Coconut Creek (Florida), ISSN 0749-0208.

In this paper, a novel two-dimensional numerical model for wave-seabed-pipeline interaction is proposed to investigate the wave-induced uplift force exerted onto a shallowly buried pipeline. Unlike previous models, the present model is fully coupled, and the effects of fluid shear stress at the seabed surface on the soil dynamic response are considered. In this study, the Reynolds-averaged Navier-Stokes equation was applied to simulate flow motions, and the level set method was used to track the free water surface. Meanwhile, Biot's poroelastic equation (u-p mode) was taken to govern the wave-induced oscillatory response of the seabed, and the pipeline was treated as elastic. After validation using data from laboratory experiments in the literature, the novel model was first employed to investigate the distribution of the wave-induced transient seabed response around the shallowly buried pipeline. Then, the effects of the wave parameters, the soil properties, and the pipeline diameter and burial depth on the wave-induced maximum uplift force exerted onto the structure were systematically examined in detail. Finally, wave-induced maximum uplift of the shallowly buried pipeline was predicted based on the numerical results, which may provide some references for engineering practice. Numerical results confirmed that both the nonlinear pipeline-seabed contacts and the fluid shear stress at the seabed surface can greatly affect the soil dynamic response, which should be considered in determining the wave-induced uplift force exerted onto a shallowly buried pipeline.

April Le Quéré, P.; Nistor, I., and Mohammadian, M., 2021. Effect of lateral spacing of structures on tsunami-induced scour. Journal of Coastal Research, 37(4), 813–826. Coconut Creek (Florida), ISSN 0749-0208.

Tsunamis are a devastating force, as seen by the extreme tsunamis that struck the Indian and Pacific Oceans over the past two decades: the 2004 Indian Ocean Tsunami, the 2010 Chile Tsunami, and the 2011 Tohoku Japan Tsunami. In those events, flood-induced scouring was found to be an important phenomenon that often led to infrastructure damage. Past research has focused on scouring around single columns and other isolated horizontal structures to attempt to understand the complex processes characterizing this phenomenon. However, given that coastal cities often comprise complex arrangements of multiple structures, often crammed, tsunami inundation flow often finds concentrated paths in between such structures; these flow concentrations increase the resulting scouring. This research is an attempt to inform the scientific community on the potential of augmented scour attributable to flow concentration that is due to the lateral spacing of structures and to compare it with nonconcentrated flow-induced scour. The authors employed the FLOW-3D numerical model for this study. This model was first calibrated using a physical model experiment performed in the dam break flume of the University of Ottawa, Canada. Results from this study demonstrate that flow concentration due to the lateral spacing of structures leads to greater scouring than for the case of an isolated structure and that the magnitude of the scour, for most cases studied, was larger than what is prescribed by the latest building codes.

Xu, H.; Cai, L.; Shao, Z.; Wang, Z.; Li, Z., and Huang, C., 2021. Prediction of shear strength of fully weathered coastal red sandstone: Influence of water content, fine content, and relative compaction. Journal of Coastal Research, 37(4), 827–841. Coconut Creek (Florida), ISSN 0749-0208.

Shear strength of coastal rock mass can be characterized by parameters such as cohesion and internal friction angle, which are relatively difficult to measure with accuracy on coastal engineering sites. This paper aims to predict shear strength of fully weathered coastal red sandstone with physical property parameters—water content, fine content, and relative compaction—that are easily measured on site. The variation of shear strength parameters with physical property parameters was obtained with indoor direct shear tests, and the real-time prediction of shear strength of fully weathered coastal red sandstone was realized by employing a decision tree model. The results show that the variation of shear strength parameters with physical properties can be accurately characterized by cubic polynomials and that the cohesion and internal friction angle can be well predicted by a 10-layer decision tree model with high accuracy. This study sheds light on the variation of shear strength of fully weathered coastal red sandstone and similar rock mass with physical properties and has practical significance for engineering conducted in such strata, which require in-time monitoring of shear strength of rock mass.

Gasc, J.; Gache, C.; Bertucci, F.; Madi Moussa, R.; Waqalevu, V., and Lecchini, D., 2021. Effects of coastline modification on coral reef fish nurseries (Moorea, French Polynesia). Journal of Coastal Research, 37(4), 842–851. Coconut Creek (Florida), ISSN 0749-0208.

This study examined the effects of coastline modification on recruitment patterns of coral reef fishes at Moorea Island (French Polynesia). The fish surveys were conducted at different distances (1, 10, and 30 m) from three natural shorelines (sandy beach, mangrove, muddy herbaceous area) and two engineered shore structures (sea embankment, artificial seawall) over 1 year. In total, 29,187 juveniles were recorded, with 32% of fish on the reefs along sandy beaches (most suitable nursery areas) and only 9% along mangroves. The temporal variation in larval recruitment highlighted that February, March, and April were the best periods for recruitment, with more than 20% of fish recorded, while the minimum (2%) was recorded in July. The fish survey showed that the reefs along each of the five shoreline types were nursery areas for a particular set of species and that many commercial species were specific to the reefs along embankments or sandy beaches. However, the reefs along engineered structures were in bad condition, i.e. less living corals and more macroalgae, in comparison with reefs along unmodified shorelines. Overall, there is an urgent need to better understand how the reefs along natural and artificial shorelines could continue to be nursery areas while facing ongoing climate change and increasing human population living along the coast in the South Pacific Islands.

Huang, Y.-G.; Yang, H.-F.; Yang, S.-L.; Wang, Y.-P.; Dai, Z.-J.; Shi, B.-W., and Wu, Q.-Y., 2021. Decadal decreases of suspended sediment concentrations within the Yangtze River Estuary: A response to human impacts. Journal of Coastal Research, 37(4), 852–863. Coconut Creek (Florida), ISSN 0749-0208.

Changes in suspended sediment concentration (SSC) in an estuary have environmental, ecological, and social-economic implications. Under human impact, annual suspended sediment discharges into the Yangtze River Estuary (YRE) display a downward trend, greatly influencing SSCs in the YRE. In this study, statistical analysis of SSCs measured in surficial water at 10 stations in the YRE indicates variations in decadal decreases in SSC, proven to be related to dam construction and soil conservation measures in the past decades. The degree of decrease varies temporospatially, with greater reduction in the annual surficial SSCs in the inner estuary than those in the outer estuary, and with the reduction rate in the former being greater in the dry season than the flood season, primarily because of the pronounced increase in water discharge during the dry season. In the outer estuary, the reduction rate in flood seasons is greater than in dry seasons because of the greater reduction in sediment discharge during the flood season. This study finds that SSC trends can be a useful reference for related studies of the YRE.

Ghrefat, H.; Zaman, H.; Batayneh, A.; El Waheidi, M.M.; Qaysi, S.; Al-Taani, A.; Jallouli, C., and Badhris, O., 2021. Assessment of heavy metal contamination in the soils of the Gulf of Aqaba (Northwestern Saudi Arabia): Integration of geochemical, remote sensing, GIS, and statistical data. Journal of Coastal Research, 37(4), 864–872. Coconut Creek (Florida), ISSN 0749-0208.

Rock and soil sample geochemical analysis was conducted to investigate the extent and causes of soil contamination in the Gulf of Aqaba region in NW Saudi Arabia. The inductively coupled plasma mass spectrometry was used to determine the concentrations of Pb, Zn, Cu, Co, Cr, Mn, Fe, Hg, Mo, and Cd in 23 soil samples and 25 samples from granitic and Cenozoic marine sedimentary formations. The geochemical results have been integrated with remote sensing, GIS, and statistical analysis to assess the severity of soil pollution in the area. The concentrations of heavy metals (ppm) in the collected soil samples were as follows: Fe (2259.70), Mn (101.85), Zn (20.15), Pb (10.74), Cr (8.67), Cu (6.10), Co (1.35), Mo (0.69), Hg (0.30), and Cd (0.17). A significant variation in the mean metal concentrations was observed for the rock samples. The correlation analysis results showed that different degrees of positive and negative relationships exist among different metals in the area. Two factors (PC1 and PC2) were identified using the principal component analysis (PCA) and were responsible for about 60% of the total variance in the data. The studied metals were separated and classified into two factors based on their geochemical features and source. In contrast, the hierarchical cluster analysis grouped the identified metals into different groups based on the similarity of their characteristics. The principal component (PC2) applied to the Sentinel-2A image classified the land cover in the area into three classes: vegetation, barren rocks, and urban area. The enrichment factor shows a relatively higher percentage of enriched Mo; however, the indices of geo-accumulation and potential ecological risk generally reveal no substantial metallic contamination in the study area. The main sources of soil contamination with metals are rock-weathering processes and various agricultural works that are widely practiced in the area.

Houser, C.; Smith, A.; George, E.; Lehner, J., and Lunardi, B., 2021. Loose and limited concepts: Using coauthor network analysis to identify potential gaps in the understanding of barrier islands. Journal of Coastal Research, 37(4), 873–881. Coconut Creek (Florida), ISSN 0749-0208.

Understanding of coastal geomorphology expands through collaborative social networks that are expressed through coauthorship. This technical communication examines the structure of coauthorship networks and research on barrier islands with a focus on nearshore bars, rip currents, swash, beach-dune interaction, foredunes, and the backbarrier. Coauthorship in coastal geomorphology is largely based on regional organizational networks and academic lineages, which may limit the cross-fertilization of ideas and techniques that would allow for an improved understanding of barrier island response to storms and sea-level rise. It is also argued that the lack of collaboration has an influence on field sampling strategies and the development of process-based models and machine learning algorithms to predict coastal barrier evolution that ultimately inform coastal management practices.