Houston, J.R. and Dean, R.G., 2016. Erosional impacts of modified inlets, beach encroachment, and beach nourishment on the east coast of Florida.

Most of the 21 inlets along the 588 km of sandy shoreline on the Florida east coast have been modified, primarily to improve navigation efficiency and safety. These modifications have usually caused significant downdrift shoreline erosion. Shoreline change data for the Florida east coast during the period from about 1869 to 1971, which was before widespread beach nourishment, are analyzed. Modified inlets during this period impacted about 25% of the shoreline and conservatively caused about 70% of the shoreline area recession and about 75–85% if counties are excluded that did not have modified inlets that caused net downdrift recession. During this same period of about 100 years, the remaining 75% of the shoreline advanced on average 46 m seaward. However, before Florida began regulating coastal construction, development often encroached on accreting shorelines, effectively masking much of the accretion. From about 1971 to 2007, a period of widespread beach nourishment, only about half of the nourishment sand was placed on eroding shorelines. About half was placed on shorelines that accreted or were stable from about 1869 to 1971 but where encroachment by development made the nourishment necessary. Over half of the recession caused by modified inlets still exists. The criteria used by the Florida Department of Environmental Protection to designate the erosional state of Florida east coast beaches was found to be problematic, since it currently designates 65% of this shoreline as eroding when only 20% eroded during the period of widespread beach nourishment from about 1971 to 2007.

van Loon-Steensma, J.M.; Hu, Z., and Slim, P.A., 2016. Modelled impact of vegetation heterogeneity and salt-marsh zonation on wave damping.

This paper analyses the effect of observed vegetation characteristics on modelled wave heights. Detailed information on species composition, as well as on height, number of stems, and diameter of the plant species of a restored salt marsh on the Wadden barrier island of Terschelling was used to parameterize and apply the Simulating Waves Nearshore – Vegetation wave model to a schematized restored salt-marsh zone in front of the dike. The results indicate that wave damping by vegetated forelands is strongly related to vegetation heterogeneity and salt-marsh zonation. The modelling works suggest that at the study site under storm conditions with a frequency of 5–10 times/y, a vegetated foreland of some 90 m in width will dampen the wave height more than 80%, whereas under extreme conditions (1/2000 y) a foreland covered with dense vegetation will dampen the wave height up to 50%. These results imply that at the study site a vegetated foreland in front of the dike leads to reduced wave attack on the dike, which may result in changed requirements for both height and revetment of the dike while maintaining the required safety level. Although there are still many questions concerning dimensions, management, and performance, developing a vegetated foreland seems an interesting strategy to adapt existing flood protection works to the effects of climate change.

Manson, G.K.; Davidson-Arnott, R.G.D., and Ollerhead, J., 2016. Attenuation of wave energy by nearshore sea ice: Prince Edward Island, Canada.

Sea ice is widely held to be decreasing in coastal waters where it is known to be effective in attenuating wave energy. This process is critical for understanding nearshore sediment transport and coastal change in ice-infested waters. We explore the attenuation of waves shoaling in nearshore ice using a simple attenuation model, hydrodynamic modelling, field studies, and daily charts of sea ice. The attenuation model is drawn from studies in deep water and modified for shallow water using field measurements. In a simple but common configuration where ice lies in a band onshore and waves enter from open water, the theory that wave energy decays exponentially as waves enter ice appears to hold true in shallow and deep water. The wave energy density in ice relates to the incoming wave energy density, attenuation distance, and an attenuation coefficient related to ice concentration and floe diameter. Much of the variability in measurements is explained by the theory, but substantial uncertainty remains. Prediction potential might be improved with higher resolution wave measurements and modelling, consideration of the rebuilding of attenuated waves in partial ice cover, and separate treatment of new ice. The adapted semiempirical theory is likely generally applicable to ice-infested coastal waters, but field studies in particular environments will be required to calibrate attenuation.

Maio, C.V.; Gontz, A.M.; Sullivan, R.M.; Madsen, S.M.; Weidman, C.R., and Donnelly, J.P., 2016. Subsurface evidence of storm-driven breaching along a transgressing barrier system, Cape Cod, U.S.A.

Relict and historic tidal channels buried within coastal barriers provide a geologic signature of environmental change, thus enhancing our understanding of how barrier systems respond to extreme storm events. Earliest maps from 1846 depict three inlets along the Waquoit Bay barrier system located on Cape Cod, Massachusetts. These channels were not depicted on maps after 1846, and we lack any information pertaining to them before 1846. The principle objective of this study was to identify the location and map the internal geometry and channel-fill configuration of the buried inlet structures using geophysical and sedimentological data acquisition methods. This was done by collecting 6.2 km of shore-parallel ground-penetrating radar data and five sediment cores ranging in depth from 4 to 5 m. The sediment cores allowed for the ground truthing of the ground-penetrating radar data and provided six samples for radiocarbon dating. The 13 paleochannels identified ranged in depths from 1.3 to 3.7 m below the present beach surface. These appeared in the radar imagery as broad U-shaped cut-and-fill features incised into adjacent barrier facies. The 13 paleochannels composed 24% of the barrier lithosome totaling 704 m in length. Individual channels were primarily less than 65 m in length and between 2.5 and 1.3 m in depth, although an additional 275-m-wide, 3.7-m-deep channel sequence was imaged and likely represents a major and long-lived paleochannel. The results will contribute toward deciphering the evolution of the Waquoit system and identify areas vulnerable to storm-driven coastal change.

Shaw, C.E., 2016. Late Pleistocene bays and reefs: Ancestors to the modern Caribbean coast, Yucatán Península, México.

Low-lying indentations along the modern Caribbean coast of the Yucatán Peninsula host shallow bays with classic crescent-shaped, white-sand beaches. These indentations have previously been explained as products of Holocene dissolution of Pleistocene limestones within a brackish coastal mixing zone. This paper demonstrates that the lows confining the modern bays were formed by sedimentary processes 122,000 ± 2000 YBP, during the late Pleistocene. A 50 km stretch of the Caribbean coast between Tankah and Playa del Carmen, here called the high coast, is characterized by rocky headlands that are underlain by fossilized coral reefs of late Pleistocene age and lows between headlands occupied by modern bays. Study of landforms using aerial photographs together with field examination of late Pleistocene calcarenite exposed in quarries has led to recognition of a series of arcuate Pleistocene beaches with large attached spits that developed during a period of falling sea level that followed the oxygen isotope substage 5e sea-level highstand. Pleistocene beaches and associated triangular spits form a series of cuspate arcs, each precisely aligned with one of the modern bays and each triangular spit aligned with the center of a modern headland. This exact and repeated coincidence of substage 5e bays with modern bays and beaches indicates that low areas occupied by modern bays lie within the lowest portions of late Pleistocene bays that were drained during the Wisconsin glacial and reflooded in their lowest parts during the post-Wisconsin rise of sea level in the Holocene.

Wen, F.; Wang, J.H., and Zhou, X.L. 2016. Response of saturated porous seabed under combined short-crested waves and current loading.

Ocean currents and waves generally coexist in a real ocean environment. However, most previous investigations have only considered wave loading or have been limited to two-dimensional cases. In this study, first we derive interaction of short-crested waves and uniform currents. Then, based on Biot's consolidation (i.e. quasi-static) theory, we establish a numerical model integrating a three-dimensional model of the seabed with combined short-crested waves and current loading. Applying the proposed numerical model, we examine the influence of current on seabed response. Numerical results reveal that current has a significant effect on seabed response. For example, a following current (current in the x direction, U₁ > 0) will increase pore pressure, while an opposing current (current in the x direction, U₁ < 0) will decrease pore pressure. The maximum relative difference of pore pressure (Δp/p₀) can be more than 30% when a following current is considered. A parametric study demonstrates that the effects of current on the seabed response will be more significant in the cases of larger incident angles of wave (Θ_w) or current (Θ_c). Transient liquefaction analysis in a fine sand seabed shows that the depth and area of liquefaction will increase when a following current exists.

Cáceres, R.A.; Zyserman, J.A., and Perillo, G.M.E. 2016. Analysis of sedimentation problems at the entrance to Mar del Plata Harbor.

Mar del Plata Harbor is an important center for the fishery industry in Argentina, and it has become an attractive site for international tourism because of the recent construction of a cruiser ship terminal. However, further development of this port halted several years ago because of the recurrent sedimentation problems in the access channel and basins. This site is characterized by advancement of the shoreline south of the harbor and a sandbank that develops across the access channel, while downdrift erosion and the associated shoreline retreat are due to partial blockage of the sediment transport caused by the harbor breakwaters. The mechanisms responsible for these sedimentation and erosion processes are examined using a coastal area morphological modeling system, MIKE 21/3 Coupled Model Flexible Mesh, developed by DHI. The morphological model was calibrated and validated against measured bathymetric changes. The model was then applied to a medium-term simulation with particular interest in the assessment of the effectiveness of re-establishing the design depth of the access channel through dredging. This morphological modeling allowed enhanced understanding of the main hydrodynamic and sedimentological processes occurring around the harbor entrance, as well as obtainment of information potentially useful for maintenance dredging. It was determined for the present hydrosedimentological conditions that the sandbank moves toward the access channel with high sedimentation rate. This means the navigation channel requires regular maintenance dredging or the construction of additional sediment retention interventions such as sediment traps, extension of the breakwater(s), etc. The efficiency of any intervention from the point of view of reducing sediment deposition at the harbor access should be verified before its implementation. In all cases, the northward transport would still be blocked, so artificial sediment bypass should be considered to protect the beaches north of the harbor.

El puerto de Mar del Plata es un importante centro para la industria pesquera en Argentina y se ha convertido en un lugar atractivo para el turismo internacional debido a la reciente construcción de una terminal de cruceros. Sin embargo, el desarrollo de este puerto se encuentra detenido hace varios años debido a persistentes problemas de sedimentación en su canal de acceso y dársenas. Debido a la obstrucción parcial del transporte de sedimentos que provoca la escollera Sur del puerto, el área costera se caracteriza por el avance de la línea de costa aguas arriba, el desarrollo de un banco de arena a través del canal de acceso y significativos procesos de erosión en las playas ubicadas al Norte del puerto. Los mecanismos responsables de estos procesos fueron evaluados mediante el Sistema de Modelación Morfológica MIKE 21/3 de malla flexible desarrollado por la empresa DHI. El modelo morfológico fue calibrado y validado mediante relevamientos batimétricos realizados en el entorno del acceso portuario. El modelo fue aplicado con una simulación a mediano plazo (tres años), con especial interés en la evaluación de la eficacia que tendría una obra de dragado para restablecer la profundidad de diseño del canal. Esta modelación morfológica permitió una mayor comprensión de los principales procesos hidrodinámicos y sedimentológicos que ocurren alrededor de la entrada del puerto, así como la obtención de información potencialmente útil para el diseño de estructuras y la planificación del dragado de mantenimiento. Se determinó que para las presentes condiciones hidrosedimentológicas el banco de arena se mueve hacia el canal de acceso con altas tasas de sedimentación, por lo cual requiere un mantenimiento regular, o la construcción de obras complementarias tal

Zhang, P.D.; Liu, Y.S.; Guo, D.; Li, W.T., and Zhang, Q., 2016. Seasonal variation in growth, morphology, and reproduction of eelgrass Zostera marina on the eastern coast of the Shandong Peninsula, China.

Seasonal dynamics of Zostera marina were monitored monthly in Swan Lake of Shandong Peninsula, China, by examining plant density, morphology, weight, and environmental factors from February 2009 to January 2010. The greatest values for shoot size and weight were obtained in summer and the smallest values in winter and early spring. Reproductive shoots appeared in late March and developed into fruits in mid-June. Fruits were fully developed into mature seeds in mid-July. Reproductive shoot size and weight exhibited clear seasonal patterns with maximum values in May for leaf length, inflorescence length, and leaf width and in June for shoot length and shoot weight. The density of reproductive shoots ranged from 4 to 40 shoots m⁻² with an average of 22.4 ± 12.8 shoots m⁻² (mean ± 95% confidence interval) in July 2009. The average number of spathes per reproductive shoot was 18.9 ± 3.3, with 7.8 ± 0.7 seeds per spathe, and the mean seed dry weight was 3.2 ± 0.4 mg. Seasonal variations in shoot density and aboveground tissue dimensions correlated positively with water temperature. This study presents the first quantitative data on the seasonal dynamics of Z. marina in China.

Wang, T.; Liu, G.; Gao, L.; Zhu, L.; Fu, Q., and Li, D., 2016. Biological and nutrient responses to a typhoon in the Yangtze estuary and the adjacent sea.

Typhoon Haikui passed through the Yangtze River estuary and the adjacent sea during the summer of 2012. Three field surveys were conducted before and after the passage of this typhoon. The effects of Haikui in this area on nutrient levels and biological production were studied by combining model data and several satellite observations. During the typhoon's passage, the water column was affected mainly by vertical mixing, which was caused by the strong wind. As the wind subsided, terrestrial runoff and offshore water intrusion became more important for changing the physical and chemical parameters. The Yangtze Diluted Water extended into the upper layer by 4 days after Haikui's landfall, largely because of the heavy typhoon-associated precipitation and considerably increased surface concentrations of dissolved inorganic nitrogen, silicate, and phosphate (by 53%, 27%, and 97%, respectively). Meanwhile, the strong onshore wind induced a strong intrusion of high-salinity offshore water in the bottom layer, and this process somewhat decreased the bottom nutrient concentrations (except for phosphate) after the typhoon. The changes in nutrient concentrations in the middle layer were quite complex because of the multiple effects of the processes described above. The increased nutrient concentrations, particularly those of phosphate, greatly promoted the growth of the upper phytoplankton in the offshore areas, although the phytoplankton biomass was found to decline rapidly a few days after the typhoon had passed. The results of this study suggest that Haikui had a profound influence on water circulation and on the chemical and biological responses in the Yangtze River estuary and its adjacent sea.

Choi, K-H.; Jang, M-C.; Shin, H.H.; Lee, W-J., and Shin, K., 2016. In situ hatching success of calanoid copepod eggs in hypoxic sediments of a coastal bay.

Hypoxia can have adverse effects on recruitment of marine copepods via its effects on egg hatching and survival of nauplii. This study investigated the effects of hypoxia on in situ hatching success of calanoid copepods in Gamak Bay, Korea, a shallow (9-m) microtidal coastal bay with long water residence times exceeding a month. Plankton emergence trap/chambers were placed into seafloor–surface sediments in July at a hypoxic site (mean = 0.6 mL L⁻¹) in the inner part of the bay and at a normoxic site in the mid bay. Nauplii that hatched and left the sediment were collected daily for 12 days, and the top 1 cm of sediment was preserved at the end of incubation. The number of eggs in the sediment was >3 × 10⁵ eggs m⁻² at the hypoxic site, about six times that at the normoxic site. Most of the eggs appeared to be subitaneous. Egg-hatching rate in the hypoxic site, however, was only 4% of that at the normoxic site, where 57% of the eggs present hatched. Cumulative numbers of eggs hatching into the hypoxic chambers were about half the numbers hatching into the normoxic chambers. The pH level in the sediment was 7.1 to 7.3 at the hypoxic site, slightly lower than in the normoxic sediment (pH > 7.5). That difference seemed to have little effect on egg hatching. High sulfide concentration at the hypoxic site (>300 μM), combined with low dissolved oxygen in summer were likely responsible for the depressed egg hatching. However, the cumulative number of eggs that hatched in the hypoxic chambers was still about half of that in the normoxic chambers. Thus, it appears that the hypoxic site might still be a significant source of juveniles for the next generation of the copepods.

Sembiring, L.; van Dongeren, A.; Winter, G., and Roelvink, D., 2016. Dynamic modelling of rip currents for swimmer safety on a wind-sea–dominated mesotidal beach.

This study applied the process-based model XBeach to predict bathymetrically controlled rip current flow occurrence, velocities and duration in the wind-sea–dominated environment of Egmond aan Zee, The Netherlands. The model is validated against data obtained during a 5-day field experiment with GPS-equipped floating drifters. Numerical model results show good agreement with data and simulate flow patterns that resemble the offshore flow through the rip channel and subsequent alongshore drift of the drifters. The average relative error of the drifter position is 0.15 and 0.19 for the cross-shore and the alongshore position, respectively. Results from the numerical experiments suggest that the rip current intensity is tidally modulated. For the period of analysis, the rips are initiated approximately 5 hours before low tide, reaching a maximum speed during low tide, and becoming inactive 3 hours after low tide. Initiation and duration of the rip current is correlated to a ratio of ∼0.55 between offshore wave height and water depth over the bar. Further experiments with the numerical model show that at Egmond, drifters that are transported offshore by the rip current are unlikely to circulate back to the shore (with only a 14% return rate). Instead, they are ejected from the surf zone and advected alongshore, dependent on the direction of the tidal current. Without wave group forcing in the model (i.e. with a stationary wave resolving approach), the model's predictability decreases, which mostly affects the prediction of the spatial flow patterns. The rip current durations can still be predicted very well, whereas the rip current magnitude is underestimated. With wind stress forcing, the model's predictive skill increases for the alongshore flow when the wind speed is relatively high, but this is not the case for low wind conditions.

Mateo, Z.R.P. and Siringan, F.P., 2016. Morphological and sedimentological signatures of Late Holocene prodelta lobes in Lingayen Gulf, Philippines.

Delta switching is an integral part of coastal evolution and may be caused by a combination of autogenic and allogenic factors. We present offshore signatures of modern and ancient prodelta deposits that document delta switching in the bayhead region of Lingayen Gulf, NW Philippines. Prodelta lobes of prograding systems are marked by areas of shoaling of about 6 m within 95 years, with around 30% clay, whereas abandoned deltas are manifested as areas of deepening of around 3 m with as much as 80% sand. The sorting and kurtosis of the mud fraction further categorize recent and current sedimentary environments and processes such as erosional and shoreface environments and areas dominated by sediment plume and normal offshore deposition. High-resolution subbottom profiles reveal the stacked and truncated nature of different prodelta lobes associated with the latest four tectonically induced delta-switching events. This documented succession of well-preserved deltaic units in a semienclosed basin illustrates the sensitivity of tropical coastal sedimentary environments to autogenic and allogenic factors such as tectonism, sea-level, and monsoonal climate changes.

Zhang, S.; Zhao, M.; Ge, T., and Wang, C., 2016. Experimental research on trenching in stiff clay by submerged vertical traveling jets.

This study investigated trenching by submerged circular traveling jets in stiff clay using an experimental method. The testing clay was prepared as mixtures of natural clay and cement with shear strength ranging from 60 kPa to 90 kPa. The jet pressure, the nozzle translational velocity, and the diameter of the nozzle all varied in the test. A cohesive sediment scouring theory was employed to reveal the mechanism of the jet trenching. It showed that the boundary layer shear force on the jet-soil interface might be the predominant mobilizing force for jet trenching. The trench depth was found to increase with the jet pressure, erodibility coefficient, and the diameter of the nozzle and decrease with the translational velocity of the nozzle and the threshold stress of the clay. The essence of the traveling jet trenching could be considered as jet erosion. The efficiency of jet trenching was found be higher when the jet worked with low pressure and large diameter. The trench depth of a large nozzle could be obtained by testing a small one.

Xie, Z.; Zhang, H.; Zhao, X.; Du, Z.; Xiang, L., and Wang, W., 2016. Assessment of heavy metal contamination and wetland management in a newly created coastal natural reserve, China.

The investigation of the content and distribution of heavy metals in coastal soils is useful for improving our understanding of biogeochemical cycles and their potential feedback to global environmental change. The accumulation of heavy metals in the Yellow River Delta (YRD) was investigated using 43 sampling sites to determine the concentrations and vertical distribution of heavy metals. Factor analysis, contamination factors, and the geoaccumulation index were applied to evaluate the contamination condition. The contamination factors and geoaccumulation index clearly indicated that the coastal ecosystems are still in their pristine state with respect to metal pollution. Factor loadings reveal that the first principal component was strongly and positively related to arsenic, chromium, copper, nickel, lead, and zinc, while the second showed highly positive factor loading on cadmium. The study demonstrated that sediment quality in the Yellow River Delta generally met the primary sediment criteria of Chinese marine sediment quality (standard no. GB 18668-20020). The YRD could still be regarded as a “clean site” because several typical heavy metals were found to have accumulated less in this region compared with other regions, e.g., the Pearl River Delta, which was heavily contaminated by heavy metals during the past decades. There is a critical need for a holistic approach to monitor heavy metal concentrations and distributions, as well as a comprehensive strategy to prevent health risks. The findings of this study could contribute to wetland conservation and management in coastal YRD regions.

Spotila, J.A.; Marshall, J.; DePew, K.; Prince, P.S., and Kennedy, L., 2016. Potential for geologic records of coseismic uplift and megathrust rupture along the Nicoya Peninsula, Costa Rica.

This study presents the first paleoseismic investigation of the Middle America subduction zone at the Nicoya Peninsula, Costa Rica. This megathrust has been intensely studied over the past decade using a range of geologic and geophysical techniques, and it experienced interplate rupture in 2012 (moment magnitude 7.6). Despite many factors that could hinder preservation of a paleoseismic record in this coastal environment, including complex deposition in a tropical mangrove setting, this reconnaissance identifies two sites where stratigraphic evidence may record relative sea-level changes associated with Holocene earthquakes. Although more work is required to better constrain the timing and nature of these events, this study suggests that the Tamarindo and Playa Carrillo estuaries contain possible paleoseismic records. At the main study site of Tamarindo, alternations between mud and peat below 1 m in depth may record relative sea-level change associated with multiple earthquakes between ∼5 and 8 ka. However, this site offers no paleoseismic evidence of late-Holocene earthquakes. Much younger stratigraphy occurs at a Playa Carrillo, where mud-peat alternations from 200 to 500 years ago could represent recent coseismic ground motions. The work presented here is limited to litho- and chronostratigraphy, however, and full interpretation of the relative sea-level histories of both sites will require quantitative, high-resolution biostratigraphic analysis. Although the results suggest paleoseismic records exist along the Nicoya Peninsula, they appear fragmentary and complex and ultimately may not provide a continuous, high-resolution paleoseismic record like those obtained at other subduction zones worldwide.

Rúa, A.; Liebezeit, G.; Molina, R., and Palacio, J., 2016. Unmixing progradational sediments in a southwestern Caribbean gulf through late Holocene: Backwash of low-level atmospheric jets.

In the last few years there has been considerable interest in the assessment of the role of tropical seas in driving paleoclimate. Despite this interest, little is known about the evolution of progradational sediments near the Panama Isthmus during the late Holocene. This paper shows the dispersion assessment of fluvial sediments into a gulf from the southwestern Caribbean on a decadal-centennial scale as recorded in three sediment cores spanning between 300 and 960 ± 35 calibrated YBP. According to end-member modeling of size classes, sediments largely comprised clay, clayey fine silt, and silty mud that flocculated by differential settling. Coarsened facies were consistent with enhanced fluvial discharge owing to increased precipitation in the circum-Caribbean. Remarkably, decreased fluvial discharge into the gulf due to aridity in the Caribbean was modulated by oceanic moisture conveyed by the low-level atmospheric jets of Panama and CHOCO. Fluvial sediments may surely fail to contribute to shoreline stability because of muddy hinterland lithology.

Mercaldo-Allen, R.; Goldberg, R.; Clark, P.; Kuropat, C.; Meseck, S.L., and Rose, J.M., 2016. Benthic ecology of northern quahog beds with different hydraulic dredging histories in Long Island Sound.

This paper evaluates benthic community composition of four shellfish beds in Long Island Sound near Milford, Connecticut, where northern quahog or hard clams, Mercenaria mercenaria (Linnaeus 1758), were harvested by hydraulic dredge. These leased beds reflect a variety of dredging histories; 0 year (dredged just before sampling began), 1 year postharvest, 2 years postharvest, and an inactive clam bed left fallow for at least 10 years. Benthic sediment was sampled at 1- to 2-week intervals from June to October 2011 using a Smith–McIntyre grab. Benthic community composition was significantly influenced by dredging history and sampling month. Abundance of benthic organisms (number of individuals and biovolume) and total organic matter concentrations were significantly greater at the 0-year site than at the 1-, 2-, and 10 -year sites, and significantly greater at the 1- and 2-year sites than at the 10 -site. Newly settled bivalves, primarily Nucula spp. and Yoldia limulata, were significantly more prevalent on the recently harvested 0-, 1-, and 2-year sites vs. the 10 -year site and highest at the 0-year site. A significantly greater number of species was observed on the 1- and 2-year sites vs. the 0- and 10 -year locations. Species richness at the 0-year site was significantly lower than at the 1-, 2-, and 10 -year sites, whereas diversity and evenness at the 0-year site was significantly lower than at the 10 -year site. This study observed successional changes in community structure of inshore clam beds related to the length of time elapsed after harvest dredging.

Wang, F.; Zong, Y.Q.; Li, J.F.; Tian, L.Z.; Shang, Z.W.; Chen, Y.S.; Jiang, X.Y.; Yang, J.L.; Yang, B., and Wang, H., 2016. Recent sedimentation dynamics indicated by ²¹⁰Pb_exc and ¹³⁷Cs records from the subtidal area of Bohai Bay, China.

To determine sedimentation rate changes across an open marine area along the west coast of Bohai Bay, more than 50 short sediment cores were collected and analyzed with their sedimentation rates estimated by excess ²¹⁰Pb (²¹⁰Pb_exc) and ¹³⁷Cs in the sediment. The surveys enabled us to explore the relationship between sediment supply changes from the rivers and the spatial/temporal deposition patterns in the shallow marine areas. Several core records show that sedimentation rates can be overestimated by the conventional constant initial concentration model based on the ²¹⁰Pb_exc curves alone. The overestimation was caused by a change of ²¹⁰Pb_exc in the top layers of these cores and this is confirmed by comparing ²¹⁰Pb_exc curves with the respective ¹³⁷Cs curves. This phenomenon is likely caused by sediment erosion or redeposition of the surface sediment at the seabed, implying present-day active sedimentary processes as a result of the drastic decrease in sediment supply from the rivers during the last 50 years. The sedimentary boundary where sedimentation rate changed is largely comparable with the timing of sediment supply change according to the river discharge data, which can be used as a local time marker for sedimentation rate comparison.

McClure, A.; Liu, X.; Hines, E., and Ferner, M.C., 2016. Evaluation of error reduction techniques on a LIDAR-derived salt marsh digital elevation model.

Accurate elevation information is a necessity for conservation and management of tidal salt marshes where elevation differences can be as little as 2 m and where sea-level rise is a critical threat. This study applied an existing method to evaluate and improve the vertical accuracy of a 1-m LIDAR-derived digital elevation model (DEM) using a real-time kinematic (RTK) GPS dataset with a vertical accuracy of ±0.02 m and local vegetation data within a tidal salt marsh. Correction factors were generated for vegetation species within each major vegetation class and produced a modified DEM of the site. Comparison between the original and modified DEM showed that the mean error was reduced from 0.16 m to −0.004 m and the root mean squared error was reduced from 0.212 m to 0.098 m. These results demonstrate that it is possible to significantly reduce vertical error contained within a salt marsh DEM derived from a LIDAR dataset using highly accurate RTK GPS data combined with vegetation data collected on a per site basis.

Chaineux, M.-C. and Charlier, R.H., 2016. Fishermen cavalry.

The short Belgian coast has been subject to numerous transformations in its physical and human geography aspects. Major changes have affected its economic geography. From an area essentially devoted to fishing, and, more inland, agriculture, it is nowadays more centred on tourism. With that new vocation some former occupations have vanished, yet some have survived as part of the folkloric patrimony. A specific and colourful example is shrimp fishing on horseback.

Rokni, K.; Ahmad, A.; Solaimani, K., and Hazini, S., 2016. A new approach for detection of surface water changes based on principal component analysis of multitemporal normalized difference water index.

Normally, to detect surface water changes, water features are extracted individually using multitemporal satellite data, and then, those data are analyzed and compared to detect their changes. In this study, a new approach, called normalized difference water index–principle components (NDWI-PCs), is introduced for detecting surface water changes. This approach is based on principal component analysis (PCA) of multitemporal, normalized difference water index (NDWI_MF). To develop the new model, the performances of various satellite-derived indices, including the NDWI_MF (the approach introduced by McFeeters), the NDWI_Gao (the approach introduced by Gao), the modified NDWI (MNDWI), the water ratio index (WRI), and the normalized difference vegetation index (NDVI), were initially examined for the extraction of surface water from Landsat data. The results indicated superiority of the NDWI_MF for this purpose. Accordingly, the NDWI_MF was calculated from the multitemporal Landsat images, and the obtained NDWI_MF images were stacked into one composite file. The PCA technique was then applied to transform the composite image into a new PCA space. Finally, the resulting NDWI-PCs were classified and analyzed to detect surface water changes. Furthermore, the applicability of the proposed NDWI-PCs approach for detecting surface water changes was evaluated and proven in comparison with some common change-detection methods, including image differencing, image thresholding, principal component analysis, and postclassification comparison.

Schmith, T.; Thejll, P., and Nielsen, J.W., 2016. Discussion of: Hansen, J. M., Aagaard, T. and Kuijpers, A., 2015. Sea-level forcing by synchronization of 56- and 74-year oscillations with the Moon's nodal tide on the northwest European shelf (eastern North Sea to central Baltic Sea). Journal of Coastal Research, 31(5), 1041–1056.

We criticize important aspects of the analysis presented in Hansen, Aagaard, and Kuijpers (2015) (hereafter “HAK”) and thereby cast doubt on their conclusions. HAK claim that 18.6-year variations in sea level are supported by tidal theory, but this is not the case; therefore, the existence of such variations must be explicitly shown. We calculated the amplitude spectrum of the annual sea level by harmonic analysis and found no significant peaks at the periods claimed by HAK. Next, we used results given by HAK to reconstruct their decomposition and formed the residuals by subtracting the decomposition from the original data. We found that the variability near 18.6 years is present in the residuals, showing that the decomposition by HAK does not describe this variability. This motivated us to redo HAK's analysis, and we found a seven times lower amplitude for the 18.6-year periodicity than claimed by HAK. Finally, we discuss HAK's mode selection criteria, based on correlation coefficients of trending series, and find them invalid. Therefore, we performed a significance test based on a Monte Carlo technique and conclude that none of the modes identified by HAK are statistically significant.

The outside 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.