Wright, E.; Kruse, S.; Forman, S.L., and Harris, M.S., 2018. Millennial scale development of a southeastern United States spit.

A prominent 4-km-long and 1-km-wide spit is located at the southern downdrift end of the Grand Strand coastline in NE South Carolina. To reconstruct a millennial scale record of spit evolution, an integrated suite of data collection was employed, including LiDAR data, ground-penetrating radar data ground truthed by vibracore and split-spoon auger data, and optically stimulated luminescence (OSL) ages. OSL ages suggest initial spit formation began around CE 1100. During the last millennium, the spit records four periods of major advance: three by OSL ages around CE 1105 to 1240, CE 1485 to 1600, CE 1725 to 1835 and one by historical records after CE 1872 until prior to CE 1980. Each section grew by southerly advance of the spit platform, revealed by dipping foreset reflectors, overlain by beach, overwash, and eolian units. Section boundaries are indicated by abrupt OSL age differences, larger ridges (>4.5 m), and, for the middle spit sections, wide downdrift platforms. Episodic growth of the spit may be related to ebb-tidal channel switching, with channel migration establishing platform development or changes in updrift sediment supply. For the central zones, lack of shoreline advance across the downdrift platform suggests a changing sediment supply. The formation of the north and north-central section and associated recurved ridges correspond with times of heightened hurricane activity in the Western North Atlantic, whereas ridges in the south section appear to be related to local hurricane and storm activity. The north-central section had a particularly rapid advance, which is attributed to increased sediment supply. The most recent advance of the spit was also influenced by jetty construction between CE 1890 and 1905. In comparison to the greater amount of research that has been done on longer term coastal geologic evolution and decadal-term shoreline change, intermediate centennial-scale variations were formerly more difficult to age date and study. Determining coastal change on intermediate time scale, however, is important for understanding coastal systems such as the Grand Strand.

Ding, L.; Zheng, H., and Zhao, X., 2018. Efficiency of the Chinese ocean economy within a governance framework using an improved Malmquist-Luenberger index.

This study provides a novel idea to assess the ocean economic efficiency in a governance framework. Using an improved Malmquist-Luenberger index method, this study estimates and decomposes the total factor environment-energy-governance performance of 11 coastal regions over 2002–2014. Furthermore, it adopts the Moran's I method to investigate the spatial structure among these coastal regions. The results show that China's ocean economy performs well on the economic front, while the introduction of governance behavior slows down the total factor environment-energy-governance performance growth between 2010 and 2014. This indicates the 12th Five-year Plan (FYP) about restoration of marine ecosystems and protection of marine reclamation activities has made certain achievements. Moreover, technical progress is the dominating contributor to ameliorate the total factor environment-energy-governance performance. The value of Moran's I shows that there is a significant spatial clustering effect on total factor environment-energy-governance performance. However, the governance policies for ocean economy have resulted in an unstable spatial structure, since there are many uncertain treatment effects, and there is excessive competition in local markets. In the future, both the state and local governments should insist on internalizing the cost of pollution treatment through technology improvement and market reform of marine resources.

Willemse, M. and Goble, B.J., 2018. A geospatial approach to managing coastal access in KwaZulu-Natal, South Africa.

In many countries minimum criteria for coastal access have been determined to ensure people's right of access. South Africa is no exception; the provision of coastal access is a legal requirement in terms of the recently promulgated Integrated Coastal Management Act (Act No. 24 of 2008). Unfortunately, as a result of working within a capacity vacuum, both human and financial, there still exists a knowledge gap pertaining to local coastal access and the provisions thereof. Given legislative requirements and public needs, this paper proposes a desktop assessment and cost-effective approach to determining reasonable coastal access. The main aim is to provide coastal municipalities in KwaZulu-Natal (KZN) with a geospatial framework to support decision making through improved understanding of current and desired coastal access localities and quality. The KZN coastline varies substantially from a pristine northern coast to a highly developed southern coast. Because of this variability the type and density of coastal access routes along the coast differ and consequently require different management strategies. This paper proposes indices to inform coastal access management. The first is a proposed access route density index considering various social, recreational, and environmental indicators. The second index assesses the status of current coastal access via a desktop study, supported by ground truthing. The final index integrates the first two indices in quantifying the quality of coastal access and defining priority areas that require urgent management attention. Three major challenges are evident along KZN's coast: limited public access in less developed regions; private ribbon developments restricting public access in highly developed regions; and numerous inappropriate informal access paths crossing sensitive coastal environments.

Amos, C.L.; Brylinsky, M.; Forbes, D.L.; Robertson, A.; Thompson, C.E.L., and Kassem, H., 2018. Stability of seabed sediments in the embayments of North Rustico, Prince Edward Island, Canada.

This paper describes a series of 15 deployments of the annular benthic flume Sea Carousel made along the two estuaries of North Rustico, Prince Edward Island (PEI), Canada: The Hunter River estuary and the Wheatley River estuary. The study was part of a wider study on the environmental impact of coastal changes and aquaculture (Mytilus edulis) development in the region. The study site was situated on the dynamic north shore of PEI that is characterised by sandy barrier islands, inlets and beaches, and muddy lagoons. The lagoons are dominated by the seagrass Zostera marina in the muddy outer parts and by Ulva lactuca in the eutrophic inner parts. The thresholds for surface erosion of cohesive sediments (0.10 < τ_crit,o < 0.75) derived from trends of suspended sediment concentration (C) increased with distance (d) into the estuary: τ_crit,o = 0.50e^−0.26d (±0.05) Pa. Location in the estuary is the best predictor of bed stability. The next best predictor is surface sediment wet bulk density (ρ_b), which takes the form: τ_crit,o = 6.67 × 10⁻⁴(ρ_b) − 0.55 Pa. Erosion rates (E) can only be correlated (significantly) with excess bed shear stress (τ_ex) by incorporation of a time (depth)-varying erosion threshold. A power function emerged of the form: E = E_oτ_ex^m kg/m²/s (0.28 < m < 1.06). The exponent is within the range of laboratory experiments reported in the literature. The still-water settling rates of eroded material are diagnostic of a wide range of sedimentation diameters varying from fine sand to medium silt. The deposition threshold (τ_d) was evaluated in a laboratory equivalent of Sea Carousel (Lab Carousel) for sites RUS11 and RUS12 and yielded a mean value of 0.51 Pa. The exponential decay constant (k) for still-water settling is strongly dependent on initial concentration and suggests a constant settling rate that fits with data from a wide variety of settings throughout Canada.

Odigie, K.O. and Warrick, J.A., 2018. Coherence between coastal and river flooding along the California coast.

Water levels around river mouths are intrinsically determined by sea level and river discharge. If storm-associated coastal water-level anomalies coincide with extreme river discharge, landscapes near river mouths will be flooded by the hydrodynamic interactions of these two water masses. Unfortunately, the temporal relationships between ocean and river water masses are not well understood. The coherence between extreme river discharge and coastal water levels at six California river mouths across different climatic and geographic regions was examined. Data from river gauges, wave buoys, and tide gauges from 2007 to 2014 were integrated to investigate the relationships between extreme river discharge and coastal water levels near the mouths of the Eel, Russian, San Lorenzo, Ventura, Arroyo Trabuco, and San Diego rivers. Results indicate that mean and extreme coastal water levels during extreme river discharge are significantly higher compared with background conditions. Elevated coastal water levels result from the combination of nontidal residuals (NTRs) and wave setups. Mean and extreme (>99th percentile of observations) NTRs are 3–20 cm and ∼30 cm higher during extreme river discharge conditions, respectively. Mean and extreme wave setups are up to 40 cm and ∼20–90 cm higher during extreme river discharge than typical conditions, respectively. These water-level anomalies were generally greatest for the northern rivers and least for the southern rivers. Time-series comparisons suggest that increases in NTRs are largely coherent with extreme river discharge, owing to the low atmospheric pressure systems associated with storms. The potential flooding risks of the concurrent timing of these water masses are tempered by the mixed, semidiurnal tides of the region that have amplitudes of 2–2.5 m. In summary, flooding hazard assessments for floodplains near California river mouths for current or future conditions with sea-level rise should include the temporal coherence of fluvial and oceanic water levels.

Zapperi, G.; Piovan, M.J., and Pratolongo, P., 2018. Community structure and spatial zonation of benthic macrofauna in mudflats of the Bahía Blanca Estuary, Argentina.

The variations in composition of the benthic community and specific physical variables of mudflats in the Bahía Blanca Estuary, across the intertidal gradient, are described. An upper mudflat, with a steeper slope and higher densities of crab burrows exists seaward of a gently-sloped lower zone, where the density of crab burrows progressively diminishes. Monthly samples were collected from both sections of mudflats to analyze the composition of macrozoobenthos, as well as physical and chemical variables in sediments. Neohelice granulata and Polydora sp. were representative species of the upper mudflat. N. granulata had significantly higher densities in January (236 ± 136 individuals per square meter [ind m⁻²]) and February (200 ± 68 ind m⁻²), and Polydora sp. had significantly higher densities in May (491 ± 398 ind m⁻²). N. granulata did not appear in samples from the lower mudflat. There, densities of Laeonereis culveri were significantly higher, with peaks in June (8604 ± 3341 ind m⁻²) and October (7604 ± 1908 ind m⁻²). In the upper section, a single peak was observed in September (2455 ± 1281 ind m⁻²). Chlorophyll-a concentrations in sediments from the upper mudflat showed a single peak in July (10.1 ± 0.77 μg cm⁻²). In the lower zone, two peaks were observed in July (10.4 ± 0.18 μg cm⁻²) and March (10.5 ± 3.1 μg cm⁻²). These occurred 2 to 3 months before the peak densities of L. culveri were observed. Bulk density, water content of sediments, and shear strength were significantly different between zones, suggesting sediments are more compact and less hydrated in the upper section and hence more resistant to erosion. Major differences were found between the upper and the lower section of mudflats in terms of their biological communities, their seasonal patterns of activity, and the characteristics of the physical environment leading to erodibility.

Tucker, C.S.; Trepanier, J.C.; Harley, G.L., and DeLong, K.L., 2018. Recording Tropical Cyclone Activity from 1909 to 2014 along the Northern Gulf of Mexico using Maritime Slash Pine Trees (Pinus elliottii var. elliottii Engelm.).

The temporally incomplete tropical cyclone (TC) observational record limits the understanding of recurrence intervals and the impacts of repeated TCs on coastal ecosystems. Growth of maritime trees near the Gulf of Mexico may be affected by high winds, precipitation, and storm surges from TCs. Proxy records, such as tree growth recorded in annual ring widths, can be used to extend TC records temporally but must be verified with the observational record first. This study develops chronologies of total ring width (TRW), earlywood ring width (ERW), and latewood ring width (LRW) from slash pine (Pinus elliottii var. elliottii Engelm.) trees located 2 km from an open saltwater bay in the Grand Bay National Estuarine Research Reserve in coastal Mississippi, U.S.A. These chronologies are compared with TC storm surge and wind speed records using superposed epoch analysis. The year after a TC occurrence, tree growth is significantly (p < 0.05) suppressed (narrower than average annual growth rings) for TRW, ERW, and LRW with respect to storm surge and shows no statistical significance with high wind speeds. Individual trees display suppression in growth for 1–6 years after TC occurrences. This study demonstrates that slash pine trees in close proximity to salt water can be used to produce chronologies of TC occurrences for the northern Gulf of Mexico region and thus can eventually be used to extended and supplement temporally the existing TC observational record.

Shaeri, S.; Strauss, D.; Etemad-Shahidi, A., and Tomlinson, R., 2018. Hydrosedimentological modelling of a small, trained tidal inlet system, Currumbin Creek, southeast Queensland, Australia.

Small tidal inlets with an entrance width of less than 50 m or a cross-sectional area of less than 100 m² have not been investigated as often as their larger counterparts. To discern the major processes responsible for entrance infilling in a small inlet system, the hydrosedimentological processes in the annually dredged Currumbin Creek (Australia) inlet system were investigated. Delft3D was applied and validated using local field measurements and regional data. A standalone regional hydrodynamic model and three nested standalone wave models provided detailed data for the offshore boundary of the more detailed creek entrance model, which was a coupled, local flow–wave–sediment transport model. The noncohesive sediment transport module was calibrated based on the volume of dredging and the net annual volume of longshore transport. The results of this hindcast model provided insight into the dominant processes responsible for the inlet's current configuration (i.e. significant refraction of incident waves to a nearly shore normal direction; a noteworthy onshore-offshore transfer of sediments; channel infilling induced by wave-induced currents; very limited sediment transport within the back-barrier lagoon because of an absence of wave-induced currents, as well as weak tide-induced currents; and infilling of the dredged area because of immersed slope stability, rather than hydrodynamic processes). Overall, the adopted modelling approach and the selected model setups proved to be a suitable combination of the available resources and tools to forecast the influence of any alteration to the current maintenance strategy. Accordingly, the identified physical processes and findings can be applied to similar cases with narrow inlet entrance widths and small back barriers with limited circulation.

Hsu, L.-C. and Lee, C.-T., 2018. The current extent and historical expansion of mangroves in the Kuantu Nature Reserve, North Taiwan.

The Kandelia candel (L.) Druce mangrove forest in the Kuantu Nature Reserve, North Taiwan, has experienced rapid expansion since 1978. This study assesses the current extent and historical expansion of the mangroves by means of aerial photograph interpretation. An analysis of a time series of aerial photographs, covering the period from 1978 to 2012, has revealed major changes in the distribution of mangroves in relation to the geomorphic changes in the Kuantu Nature Reserve. The results indicate that the area-increasing rate was highest (2.27 ha/y) during the 1986–94 period, meaning the most rapid encroachment of mangroves into the habitats of Cyperus and Phragmites saltmarshes. Based on the Shannon diversity index t test, with the encroachment of Kandelia, the landscape composition in the Kuantu Nature Reserve has been dominated by the mangrove swamp of Kandelia. The geomorphic changes in the area of accretion and erosion were derived from the 0-m contour in the 1:5000 topographic maps in 1978, 1986, 1994, and 2005. Based on a review of related literature, the possible driving forces of geomorphic changes are explained by human impacts (e.g., land subsidence because of the overpumping of groundwater and collapse triggered by sand pumping) and natural forces (e.g., increased accretion induced by mangroves and headward expansion of tidal creek and typhoon-induced erosion). The complicated interplay between vegetation and landform in the Kuantu Nature Reserve is discussed from the viewpoint of biogeomorphic succession. Similar mangrove expansion cases are also examined.

Xing, C.; Zhao, Q.; Hu, Z., and Liu, Y., 2018. Direct observations and modeling of summertime coastal circulation patterns in the western Bohai Sea.

Eutrophication of the coastal waters in the western Bohai Sea results in serious environmental problems. In summer, severe brown tide frequently happens in the Qinhuangdao coastal areas, causing enormous losses to the local fishery. A survey array with four sets of seabed-based current observation systems equipped with acoustic Doppler current profilers was deployed in September 2013 to investigate the hydrodynamic background of the brown tide. The observations suggest that the shore currents flow generally northward and offshore currents flow southward during the survey period. The coastal circulation system and its formation mechanisms are studied with a three-dimensional nested-grid ocean circulation model. The model results suggest that coastal currents form a clockwise eddy-shaped circulation system with a diameter of 65 km. Numerical sensitivity experiments imply that the tides and summer monsoons generate the observed coastal circulation system. The combined effects of the tidal residual currents and wind-induced currents transport water northward and shoreward, resulting in a higher water level in the north of Qinhuangdao. The barotropic pressure gradient then produces southward pressure compensation flows. Consequently, the northward shore currents and the offshore southward compensation flows form the clockwise eddy-shaped circulation. The summer monsoons are important driving forces to generate the observed coastal circulation system. Because the summer monsoons are periodically occurring meteorological processes of this region, the observed coastal circulation system is anticipated to appear every summer. The environmental problems in the Qinhuangdao coastal areas are mainly induced by the land-based pollution discharges. Combined with observations on the surrounding land-based pollution discharges, the information obtained through this study could be used to track the nutrient transport and eventually help to mitigate adverse phytoplankton blooms.

Mora, A.; Bautista, E.; Méndez, F., and Barbosa, M., 2018. Asymptotic solution for the reflection of long water waves by asymmetric convergent/divergent harbours.

In this work, formulas for the reflection and transmission coefficients of linear long water waves propagating along a slender harbour composed of an asymmetric convergent/divergent region connected to uniform inlet and outlet regions are obtained. The governing equation is solved using the Wentzel-Kramers-Brillouin singular perturbation technique. A better sheltering function of the harbour is found for a divergent harbour with asymmetric variations in width. For convergent harbours, the largest values of the reflection coefficient are obtained for the limit in which the length of the harbour is of the same order of magnitude as the wavelength. A zero-reflection phenomenon occurs for a convergent symmetric harbour with a linearly varying width and a parabolic depth profile. The results reveal that in the presence of a linear transition in either width or depth, the reflection coefficients exhibit oscillating behaviour. The present mathematical model is compared with a simple numerical solution and with another analytical solution expressed in terms of Bessel functions. The formulas are also checked by considering an energy identity, which is satisfied to very good accuracy. Therefore, the deduced formulas can serve as a preliminary means of identifying which harbour geometries can significantly amplify or attenuate the amplitudes of water waves.

Jury, M.R., 2018. Characteristics and meteorology of Atlantic swells reaching the Caribbean.

The characteristics of Atlantic swells reaching the Caribbean (19° N, 66° W) are described using wave hindcast and buoy datasets. The methods include calculation of histograms, scatterplots, temporal trends, ranking of extremes, meteorological case analysis, comparison of alternative datasets, and an assessment of similarity between cases. Northerly swells occur 29% of the time, with a mean height and period of 2 m and 8 seconds. A slight upward trend in wave period during 1998–2013 was related to an expanding anticyclonic Hadley circulation in the northwest Atlantic. An extreme case analysis illustrates how a storm near Bermuda on 16–20 March 2008 intensified as high pressure near Greenland blocked its progression. The cold air outbreak from the storm and 20 m/s northerly wind gusts induced heat fluxes up to 1000 W/m² over the Gulf Stream outflow. Swells >6 m traveled southward, attenuating to 4–5 m and damaging coastal infrastructure in northern Puerto Rico. Similar weather patterns are found in the next five ranked cases and suggest that polar blocking is an essential feature of extreme Atlantic swells reaching the Caribbean.

Claudino-Sales, V.; Wang, P., and Carvalho, A.M., 2018. Interactions between various headlands, beaches, and dunes along the coast of Ceará State, Northeast Brazil.

The equatorial coast of NE Brazil consists of long and wide sandy beaches, segmented by rhythmic headlands, sometimes with seacliffs. Large and extensive mobile transgressive dunefields distribute up to 6 km landward of the coastline. The coastal area of Ceará state, as examined in this study by the means of measurements, field work, and remote sensing, illustrates a characteristic morphology composed of interactive headland, beach, and dune systems. Under persistent unidirectional wind and wave forcing, the morphodynamics of the studied coast is strongly controlled by the headlands because they produce an interruption of the longshore sand transport at their contact, resulting in accretion updrift of the headland and in erosion downdrift of the headland. The headland bypass dunefield activates one major mechanism and dynamics of the system headland-beach-dune because they refeed the beaches in the process of erosion downdrift. Littoral bypass is also an important process, supplying the cell with new sand, together with the erosion that takes place in the zetaform beach. Such a unique system can be strongly affected by anthropogenic activities, which can influence nearly all the factors at all temporal and spatial scales.

Edwards, T.C.P. and Mitchell, S.F., 2018. Trace fossils in clastic beachrocks at the Yallahs Salt Ponds, Jamaica: Implications for beachrock cementation.

The extent and importance of trace fossils preserved in clastic beachrock from the southern section of the Yallahs Salt Ponds on the SE coast of Jamaica are described. The beachrock contains a seaward-dipping facies of cemented sandstones and conglomerates and a landward facies consisting of cemented sandstones packed with the trace fossil Psilonichnus, which is produced by the ghost crab Ocypode quadrata (Fabricius). The seaward-dipping bedded facies represents more than 95% of the beachrock at the Yallahs Salt Ponds and has an exposed height ranging from 6 to 50 cm and lateral continuity of 1 to 200 m. The bioturbated facies, which represents less than 5% of the beachrock at the Yallahs Salt Ponds, was only found at three localities. It has an exposed height of 40 to 60 cm, with outcrops traceable for 6 to 30 m along the beach. These bioturbated Psilonichnus-bearing units demonstrate that beachrock cementation occurred within the intertidal zone and the lower supratidal zone, where modern burrows of Ocypode are found. The high density of Psilonichnus burrows indicates multiple generations of Ocypode burrowing activity, demonstrating that the beach system was stable and was not affected by any tropical storms or hurricanes for an extended period before cementation. Psilonichnus burrows penetrate the entire thickness (up to 50 cm) of the beachrock at the three localities where they are preserved, and this indicates that a single episode of cementation was responsible for beachrock formation. A second episode of cementation is demonstrated by cobbles and blocks of broken beachrock cemented to the top of the exposed beachrock outcrop; this presumably occurred much later than the first phase of cementation.

Huang, X.; Wang, X.; Li, X.; Xin, K.; Yan, Z.; Sun, Y., and Bellerby, R., 2018. Distribution pattern and influencing factors for soil organic carbon (SOC) in mangrove communities at Dongzhaigang, China.

Mangrove wetlands constitute an important carbon pool and play an important role in the global carbon balance. Understanding the distribution and influencing factors for soil organic carbon (SOC) in different mangrove communities can improve the estimation of carbon sink capacity. The SOC content and physicochemical properties were investigated from six mangrove communities dominated by Avicennia marina, Aegiceras corniculatum, Bruguiera sexangula, Sonneratia apetala, Rhizophora stylosa, or Ceriops tagal in Dongzhaigang, Southern China. The SOC content ranged from 2.60 to 89.51 g kg⁻¹ with a mean of 18.35 g kg⁻¹. The SOC content and density decreased with the depth from surface to bottom and with the tidal gradient from the low intertidal zone to the high intertidal zone except for the SOC density in the soils of the three arbor communities (S. apetala, R. stylosa, and B. sexangula). The SOC content was more related to soil nutrient elements such as total nitrogen, total phosphorus, and total potassium than to pH, bulk density, conductivity, and other soil environmental factors. Among these six mangrove plants, R. stylosa and A. corniculatum should be highly prioritized during mangrove restoration for the higher soil carbon sequestration rate and the stronger adaptive capacity.

Wang, Y. and Wang, Z.-L., 2018. Shifts of sediment microbial community structure along a salinized and degraded river continuum.

Succession of sediment microbial community along salinized and degraded river continuums where discharge declines and nutrient loading increases has received little attention. This issue was studied in a 120-km sediment continuum from upstream to estuary of the Jiyun River, northern China. Microbial community was investigated by phospholipid fatty acid (PLFA) analysis and 16S ribosomal ribonucleic acid (rRNA) gene sequencing. Microbial PLFA contents varied from 1.48 to 7.64 nmol g⁻¹. Salinity decreased microbial, bacterial, and actinomycetic PLFA contents (p < 0.05), but had little effect on fungal PLFA contents. Dissolved organic carbon and dissolved nitrogen increased microbial, bacterial, and actinomycetic PLFAs (p < 0.05), but did not affect fungal PLFAs. Fungal PLFAs were mainly associated with the contents of sediment organic carbon (SOC) and total nitrogen (TN). Salinity decreased the ratio of Gram-positive/Gram-negative PLFAs but not the ratio of fungal/bacterial PLFAs. Bacterial communities were dominated by Proteobacteria, Firmicutes, and Bacteroidetes phyla. PLFA analysis and 16S rRNA sequencing returned similar results with respect to the change in bacterial community composition. Shannon–Wiener indices of bacterial operational taxonomic units were negatively correlated with SOC and TN. In conclusion, salinity and nutrients are collectively regulating the shifts in sediment microbial community structure along the river continuum.

Zhang, T.; Tang, S., and Zhan, H., 2018. Using satellite sensors and in situ observations to monitor phytoplankton blooms in the Pearl River Estuary.

Eutrophication in the Pearl River Estuary (PRE) has become severe with the rapid urbanization of the Pearl River Delta in recent years. As a result, large-scale phytoplankton blooms occur frequently because of eutrophication. This study investigated a massive Cochlodinium geminatum bloom near the mouth of the Pearl River in August 2011 based on data from both in situ measurements and satellites. Both methods provided a useful approach for monitoring phytoplankton blooms. The in situ measurements illustrated a high concentration of algal cells (1.5 × 10⁷ cells L⁻¹) in the study area, and the bloom reached dimensions of approximately 10 to 15 km in length, 8 to 10 km in width, and 100 km² in area based on continuous field measurements. A chlorophyll algorithm for satellite sensors was developed based on in situ chlorophyll concentrations and remote sensing reflectance data collected during six cruises from August 2009 to July 2010. The algorithm was applied to Medium Resolution Imaging Spectrometer full-resolution data at the daily scale (300 m at nadir) and obtained details regarding the spatial distribution and temporal variations of the phytoplankton bloom that were consistent with the in situ measurements. An abrupt shift in wind direction and an extreme drought increased the residence time of nutrients and led to the phytoplankton bloom.

Chen, C.; Melville, B.W.; Nandasena, N.A.K., and Farvizi, F., 2018. An experimental investigation of tsunami bore impacts on a coastal bridge model with different contraction ratios.

Tsunamis are natural hazards that have damaged many coastal bridges worldwide in recent years. As a contribution to an important area of coastal research, this study investigated tsunami bore impact on a bridge model with different contraction ratios. The time histories of the horizontal force, vertical force, and overturning moment on a deck-pier structure in a tsunami flume were measured by a load cell at the base of the structure. Results show that different stages of the flow motion were observed during the bore-bridge interactions. The time histories of tsunami loads on deck-pier structures reveal that the horizontal force was characterized by four stages, the vertical force was characterized by three stages, and the overturning moment was characterized by four stages. The maximum upward force and the maximum overturning moment occurred at the same time in the splashing stage. The maximum horizontal force occurred in the water-accumulation stage. The maximum downward force occurred in the recession stage. Tsunami loads increased with increasing bore strength, and for most bore strengths, the effects of the contraction ratio on tsunami loads were different for horizontal force, vertical force, and overturning moment. Finally, on the basis of experimental data, equations for estimating tsunami loads are proposed as functions of the bore height and the contraction ratio.

Turner, R.E.; Kearney, M.S., and Parkinson, R.W., 2018. Sea-level rise tipping point of delta survival.

The estimated rate of global eustatic sea-level rise (RSLR) associated with the formation of 36 of the world's coastal deltas was calculated for the last 22,000 years. These deltas are located in a variety of environmental settings with respect to tidal range, isostasy, and climate. After correcting the original uncalibrated radiocarbon age estimates to calibrated years, 90% of the deltas appear to have formed at an average age of 8109 ± 122 before present (BP) and a median age of 7967 BP. This age corresponds to a period of significant deceleration in the RSLR to between 5 mm y⁻¹ and 10 mm y⁻¹, and is in agreement with two regional estimates of vegetation growth limits with respect to RSLR. This RSLR tipping point for delta formation can be used to inform forecasts of delta resiliency under conditions of climate change and concomitant SLR. The RSLR is accelerating and will likely be several times higher than the formation tipping point by the end of this century. Hence, the world's deltaic environments are likely to be lost within the same time frame.

Gainza, J.; Rueda, A.; Camus, P.; Tomás, A.; Méndez, F.J.; Sano, M., and Tomlinson, R., 2018. A meta-modelling approach for estimating long-term wave run-up and total water level on beaches.

Wave run-up is defined as the maximum vertical extent of wave up-rush on a beach or structure above the sea water level from wave breaking. Wave run-up is responsible for beach and dune erosion and can be an important component of coastal flooding. Run-up can be estimated using either empirical formulations or sophisticated wave-breaking models with high computational demand. On the other hand, meta-models are efficient approximations of physical-process models that enable researchers to obtain long-term time series of wave dynamics. These hybrid models are developed by combining statistical techniques and numerical models. In this study, a methodology to transform offshore sea conditions to long-term time series of wave run-up is described. The methodology combined the construction of two meta-models of offshore wave propagation to coastal areas and of nearshore wave transformation to run-up. Clustering techniques were then implemented to select a subset of spectral patterns of the offshore conditions for nearshore transfer and a subset of sea states for reconstructing the run-up. Multivariate, radial-basis functions were then fitted to the outputs of the wave propagation and wave run-up simulations to reconstruct the time series of sea-state parameters in shallow water and the time series of run-up. This methodology was applied to Palm Beach on the Gold Coast (QLD, Australia). The nearshore wave climate was validated quantitatively, whereas the reconstructed wave run-up and total water-level time series was validated with a qualitative approximation, confirming that this methodology is capable of accurately transforming the offshore wave conditions into run-up time series. The total water levels were also reconstructed to show the applicability of the results to probabilistic flood-risk analyses.

Meeder, J.F. and Parkinson, R.W., 2018. SE Saline Everglades transgressive sedimentation in response to historic acceleration in sea-level rise: A viable marker for the base of the Anthropocene?

Rate of global eustatic sea-level rise during the Holocene Epoch has been identified as the principle cause of observed changes or inferred evolution of nontectonic coastal systems in mid- to low-latitude areas. The rate of rise is now three times faster than it was for the past several thousand years and similar to values associated with the middle Holocene marine transgression. This acceleration can be attributed to human-caused global warming. In this investigation, the effects of accelerating sea-level rise on coastal sedimentary environments of the SE Saline Everglades were quantified. The results reveal historic changes to coastal habitat, sedimentation, and stratigraphy that are transgressive. These changes initiated during the early 20th century and are attributed to accelerating sea-level rise. As this acceleration and the resulting geologic record is a suspected consequence of human-induced global warming, the paper concludes with a discussion of the relevance of these observations, in tandem with others, to the current debate over the utility and use of the proposed Anthropocene.

The external peer reviewers of the Journal of Coastal Research (JCR) have generously donated their time to conduct the review process, which includes the thorough evaluation of manuscripts by providing comments and recommendations to the Editor-in-Chief concerning the ultimate disposition of submitted material. Because we frequently receive reviews from specialists outside of our own Editorial Board, we acknowledge with thanks the following reviewers who have vetted papers submitted to the JCR. Their interest and cooperation are much appreciated.