Román-Rivera, M.A. and Ellis, J.T., 2018. The king tide conundrum.

Over the last decade the concept of “king tides” has become a common colloquial term to describe higher than normal high tides. The terminology originated in 2009, when Australia experienced their highest seasonal tides in almost 20 years. In response, a public engagement program, “The King Tides Project,” was formed that has since spread globally. Discrepancies regarding the definition and frequency of king tides can be identified between the different initiatives. This communication analyzes the multifaceted and contradictory meanings of king tides and concludes by providing a holistic and comprehensive definition.

Erdmann, W.; Scheffers, A.M., and Kelletat, D.H., 2018. Holocene coastal sedimentation in a rocky environment: Geomorphological evidence from the Aran Islands and Galway Bay (western Ireland).

Rocky shores predominantly comprising coarse gravel and boulders are a neglected area of research, in part because of the difficulty in undertaking laboratory analyses on such environments. This paper is concerned with the geomorphology of the deposition of exceptional large boulders in cliff-top positions along the Aran Islands' Inishmaan, Inishmore, and Inisheer coast. These deposits are compared with other depositional units such as isolated finer sediment archives and tonguelike washover features associated with small to medium-sized boulders. Micromorphological signatures from limestone dissolution onshore and bioerosive patterns from the tidal frame were also investigated, with particular consideration of the relative age of boulder movement. Field studies included near-time inspection of the transport power during the strongest storms in living memory in winter 2013–14. To explore spatial and temporal variation in boulder deposition, numerical data for event chronologies are included. The paper also discusses rates of cliff retreat and movement of boulder ridges and contains an evaluation of the storm-only hypothesis vs. contribution of tsunamis to boulder movement.

Dally, W.R. and Osiecki, D.A., 2018. Evaluating the impact of beach nourishment on surfing: Surf City, Long Beach Island, New Jersey, U.S.A.

Utilizing the Cornell University Long and Intermediate WAVE (COULWAVE) Boussinesq wave model, the effect of the construction of a conventional beach nourishment project in Surf City, New Jersey, on the quality of the local surf break is examined in detail. A 20-year-long nearshore synthetic wave record is first developed for use in creating a monthly wave climate “almanac” so that typical seasonal effects on surf-break quality can be objectively portrayed. The wave model is then run with preconstruction bathymetric conditions, and with three postconstruction surveys performed in subsequent months. Construction of the nourishment project was found to affect the quality of the surf break adversely by (1) compression of the surf zone, (2) an increase in the occurrence of “closeouts,” (3) a shift in breaker type toward collapsing breakers, particularly during high tide, and (4) an increase in wave reflection—findings that are in agreement with anecdotal testimony offered by local surfers. On the basis of modeling results conducted using the sequential postconstruction surveys and the wave almanac, it appears to have required nominally 21–22 months for the surf-break quality to return to preproject conditions. A paradigm shift in the design and construction of beach nourishment projects in the United States is required if such effects are to be avoided, and several options are offered and discussed.

Bevington, A.E. and Twilley, R.R., 2018. Island edge morphodynamics along a chronosequence in a prograding deltaic floodplain wetland.

Much of the previous research on coastal deltaic land building has focused on the planform delta dimensions; whereas this research focuses on shifts in vertical elevation and deltaic island edge cross-sectional morphology in relation to a proposed conceptual model of deltaic island edge morphological development. This study was conducted using data collected from the Wax Lake Delta in the northern Gulf of Mexico. Island edge cross-sectional elevation profiles were extracted from a 2012 LIDAR elevation survey. Four morphometric variables (levee width, interior slope, mean elevation range, and total elevation range) were selected to describe the shape of each of these profiles, and each profile was also assigned to an age class, which was determined based on mapping of historic deltaic island extent from aerial imagery. Multivariate analysis of variance was used to test the effect of age class and distance from the upstream end of the island on these four morphometric variables. Results indicated that both age and the distance within age were statistically significant predictors of island edge cross-sectional morphology. Field-surveyed elevation transects also followed the predicted pattern of morphologic change and illustrated that the shifts in morphology can occur very rapidly within this system—over a matter of a few months—as the result of a single large river flood. High soil percent organic matter was also found to correlate to high elevation in field-surveyed transects, indicating that biological processes such as organic matter production and accretion may also play an important role in morphological development of deltaic floodplain wetlands.

Hyatt, M.W.; Anderson, P.A., and O'Donnell, P.M., 2018. Influence of temperature, salinity, and dissolved oxygen on the stress response of bull (Carcharhinus leucas) and bonnethead (Sphyrna tiburo) sharks after capture and handling.

Capture and handling stress can induce acidosis in sharks. This response, endured during commercial bycatch and in catch-and-release recreational fisheries, could be exacerbated in certain environmental conditions. To assess environmental influence on stress response, changes in acid-base, blood gas, and metabolite analytes (pH, pCO₂, and lactate) measured with the i-STAT portable clinical analyzer were evaluated immediately after capture and removal from gillnets among wild bull (Carcharhinus leucas) and bonnethead (Sphyrna tiburo) sharks caught in waters of differing temperature (T), salinity (Sal), and dissolved oxygen (DO). Time from capture to blood collection (C-BD) was also recorded. Effects of T, Sal, DO, and C-BD on acid-base physiology were evaluated by modeling their ability to predict pH, pCO₂, and lactate concentrations using ordinal logistic regression (OLR). The OLR models suggest that C. leucas sharks experienced a mixed metabolic and respiratory acidosis in warmer waters and at the low end of their salinity tolerance, and that S. tiburo sharks experienced a metabolic acidosis in warmer waters with a potential for respiratory acidosis at the high end of their salinity tolerance. In S. tiburo, capture and handling time exacerbated acidosis. Based on these findings, it is recommended that commercial and catch-and-release fisheries conduct operations cautiously during times of the year when water temperatures are high and salinities are at either extreme, by decreasing soak times, using the strongest proper tackle gear to reduce fight times, and releasing sharks as soon as possible after capture and detection.

Rebenack, C.E.; Cherubini, P., and Anderson, W.T., 2018. Developing a carbon isotope chronology for a coastal subtropical tree species with variable subannual tree-ring growth.

Stable carbon isotopes in tree rings are proposed to be used to build a chronology for coastal Pinus elliottii Engelm. var. densa growing along a hydrological gradient in the subtropical Lower Florida Keys. Pinus elliottii var. densa exhibits distinct growth rings; however, cross-dating is difficult because of inconsistent ring growth and the presence of frequent intra-annual density fluctuations (IADFs), or false rings. The δ¹³C values of earlywood and latewood were used to both identify IADFs and cross-date the trees to build a site chronology (1922–2006). The formation of the IADFs is likely related to moisture availability and the age of the tree, and the presence of IADFs varied among individual trees. A traditionally derived ring-width chronology was compared and contrasted with one developed from the δ¹³C values of the α-cellulose components of tree rings in four trees. The tree that showed the highest sensitivity and the tree living closer to the edge of the freshwater lens had a tendency to produce more IADFs during wetter-than-usual summers, while IADFs in the other two trees were more likely to appear in drier summers and wetter El Niño winters. All four trees exhibited five different seasons of prolonged stress that temporally corresponded to the passage of six major hurricane events (≥category 3). The most recent of these, Hurricane Wilma in 2005, created a large storm surge in the Lower Florida Keys that produced a stress response in the δ¹³C values. The δ¹³C chronology developed from tree rings within a single radius in each tree showed similar variability to a traditionally derived ring-width chronology that required the measurement of multiple radii to construct. This study shows Pinus elliottii var. densa to be a potentially viable source of dendrochronologically derived paleoclimate records, which has implications for improved coastal water management in a system where freshwater input relies solely on precipitation.

Wang, T.; Yu, W.; Zou, X.; Zhang, D.; Li, B.; Wang, J., and Zhang, H., 2018. Zooplankton community responses and the relation to environmental factors from established offshore wind farms within the Rudong coastal area of China.

The goal of this study was to examine the responses of the zooplankton community to the establishment of an OWF, the causes of any observed effects, and their relation to environmental factors in the study area. This article describes the results of an investigation into the zooplankton community and the main environmental factors affecting that community based on data obtained from three cruises in May, August, and November of 2015 in the area of the Longyuan OWF in Rudong, China. This study analyzed the spatiotemporal distribution of zooplankton, including data obtained before the construction of the wind farm, to assess any postconstruction change in the zooplankton community. Data from the zooplankton community were analyzed using canonical correlation analysis, redundancy analysis, and multiple regression analysis. The analysis indicates that the presence of the wind turbine foundations reduced the quantity of the macrozooplankton significantly (the percentage of change was −96.87% in the autumn, and −26.70% in the spring), and reduced the biomass slightly in autumn (the percentage of change was −58.20%) or increased the biomass in the spring (the percentage of change was 75.77%). However, the quantity of the microzooplankton significantly increased (the percentage of change was 542.76% in the spring) or decreased slightly (the percentage of change was −86.25% in the autumn). The water also showed a postconstruction trend toward eutrophication in this study area. The data also showed that water temperature, dissolved oxygen, suspended matter concentration, and pH were the most important factors influencing the zooplankton community. The suspended-matter concentration had opposite effects on the macrozooplankton and microzooplankton, suggesting that the postconstruction zooplankton community might show a trend toward miniaturization.

Foster, G.; Riegl, B.M.; Foster, K.A., and Morris, L.J., 2018. Acoustic detection and mapping of muck deposits in the Indian River Lagoon, Florida.

Locating significant deposits of muck (semifluid, fine-grained, organic-rich sediment) is an important aspect of estuarine conservation and management. The 38-kHz signal of a dual-frequency, single-beam acoustic survey of drift macroalgae was repurposed post hoc to locate and measure the horizontal and vertical extent of muck deposits within Indian River Lagoon, Florida. Raw echo returns were segmented into 5-cm strata of echo intensity, and a series of postprocessing algorithms were written to identify the characteristic pattern of backscatter associated with muck. Twenty-three deposits thicker than 0.5 m were identified within the 283-km² survey area, nearly all of which were found within depressions of the Indian River (IR). The quantity of muck was estimated at 1.87 × 10⁶ m³, roughly four times the quantity slated for removal from the Eau Gallie River and Elbow Creek (Florida) in 2016. The quantity of muck within the 110-km traverse of the IR Intracoastal Waterway (ICW) was estimated at 5.31 × 10⁶ m³. Muck deposits within the 31-km traverse of the Banana River (BR) ICW were deeper (μ = 1.22 vs. 0.51 m), but muck volume was difficult to estimate because of the uncertain boundaries (i.e. channel width) of the BR ICW. The decision of whether to remove the significant volumes of muck within the 23 deposits and the ICW must consider ecological impact relative to concentrations of muck at the discharge of tributaries. Nonetheless, this extra layer of information was achieved with only a modest increase of surveying and postprocessing effort. Synergies such as this will be important in an era of monitoring and management cost constraints.

Shih, R.-S.; Weng, W.-K., and Li, C.-Y., 2018. Experimental study on the generation and attenuation of landslide tsunamis.

Landslide tsunamis, triggered by large earthquake-induced submarine landslides, have the potential to devastate coastlines. The submarine topographies around Taiwan and Japan are similar, with both island nations located in fault zones and earthquake-prone regions; therefore, the effective dissipation of submarine landslide–induced tsunamis warrants investigation. In this study, the formation and attenuation characteristics of landslide tsunamis were experimentally investigated through hydraulic model tests. In particular, the effects of landslide geometry and kinematics on wave characteristics, as well as the effects of volume, slope of the sliding bed, and landslide height on the characteristics of the initial wave, were experimentally studied. In addition, the performance of two types of breakwaters (undulating and screen pipe) in attenuating the wave energy and impact forces of solitary waves was examined.

Flores-Cárdenas, F.; Millán-Aguilar, O.; Díaz-Lara, L.; Rodríguez-Arredondo, L.; Hurtado-Oliva, M.A., and Manzano-Sarabia, M., 2018. Trends in the Normalized Difference Vegetation Index for mangrove areas in northwestern Mexico.

Impacts of climate forcing on mangrove ecosystems have been highlighted by several authors. Nowadays, free access to Landsat imagery represents an opportunity to explore the likely impacts of climate variability on mangrove ecosystems using extended time series of vegetation indices—such as the Normalized Difference Vegetation Index—as proxies of health status. A comparison of time series of Normalized Difference Vegetation Index for mangrove areas located in La Paz (Baja California Sur, Mexico) was performed and the linear trend was evaluated for statistical significance. A significant and negative trend was observed for mangroves located in areas with limited freshwater inputs. In addition, a low but still significant correlation was observed between Normalized Difference Vegetation Index anomalies and the Multivariate El Niño Index for the 1993–2011 period. Analysis of time series suggested that mangroves located in areas with hydrologic stress are responding with a health decline and a weak response to El Niño Southern Oscillation events.

Naseem, S.; Husain, V., and Bano, S., 2018. Origin of salinity and other constituents in Indus deltaic plain groundwater, Thatta District, Pakistan.

Physico-chemical and microbiological analyses of 32 groundwater samples from the Sujawal and Makli areas of Thatta District, Sindh Province, Pakistan, were carried out to reveal the source of major ions and high salinity. Data reveal that aquifers in the study area show high salinity due to various geochemical phenomena, including cation exchange, mineral dissolution, evaporation, seawater intrusion, and anthropogenic activities. Shallow wells in the area are highly polluted due to unlined sanitation ponds, fish ponds, and waste dumps, as shown by microbiological data. Minerals found in subsurface soil are quartz, calcite, calcian-albite, muscovite, and phlogopite, which could be sources of high salinity and fluoride in groundwater. High arsenic in subsurface soil can be related with Holocene aquifers. However, the alkaline pH and oxic nature of the aquifers are not favorable for the release of arsenic in the groundwater of the study area. Therefore, most of the aquifers in the area are free from arsenic.

Far, S.S.; Wahab, A.K.A., and Harun, S.B., 2018. Determination of significant wave height offshore of the Federal Territory of Labuan (Malaysia) using generalized Pareto distribution method.

Probabilistic evaluation of surface waves was undertaken to estimate extreme wave heights for several return periods to use them in coastal and offshore constructions in the Labuan region. Generalized Pareto distribution (GPD), which is the standard practice in mainstream extreme statistics, was developed in MATLAB programming. Several diagnostic plots were drawn to ensure the validity of the GPD model. Extreme wave heights were estimated for several return periods and the confidence intervals band was determined for the estimated extreme wave heights. The wave height data set used in the modeling was observed during a 41-year period from 1949 to 1989, in the South China Sea, inside the offshore area of the Federal Territory of Labuan, off the coast of Sabah, Malaysia. The results highlight the merits associated with the model and formulas. The comparison of results of this study with preceding studies over the same data set represents the credibility of the GPD. The GPD model was successfully fitted for the data, and the obtained extreme wave height is 4.71 m for the return period of 100 years.

Tobing, S.L.; Thetford, M., and Miller, D.L., 2018. Germination and predation of Quercus geminata and Quercus myrtifolia acorns on Santa Rosa Island, Florida.

Scrub oak species are an important component of barrier island and xeric mainland scrub ecosystems. Limited recruitment of scrub oaks has been noted on barrier islands. This study evaluated several factors believed to alter germination of the scrub oak species Quercus geminata (sand live oak) and Quercus myrtifolia (myrtle oak) along interior dune fields and swales of Santa Rosa Island in the western panhandle of Florida. Influences of dune-field microrelief (interdunal swale or low-lying dune), vegetation cover (vegetated and unvegetated), and seed placement (buried and surface) on germination of acorns were analyzed. Predation of acorns with and without protection from nonburrowing herbivores (open-bottom cage and no cage) was also evaluated. Acorn predation was high. Less than 1% of Q. myrtifolia acorns were recovered outside cages. Only 33% of Q. geminata acorns were recovered outside of cages, with acorn loss reduced only by burial. Burrowing beach mice were able to access acorns within cages. Recovery inside cages was also greater when acorns were buried. Germination of Q. geminata acorns was 15% and was greatest when acorns were buried but was not influenced by microsite or vegetation cover. Germination of Q. myrtifolia was 74% and greater when buried but similar regardless of microsite and vegetation cover. Scrub restoration strategies to increase germination of these two scrub oak species would benefit from an approach that implements direct seeding (burial) in mesic microsites, while sites with strong predator pressure would further benefit from addition of physical protection from seed predators.

Tereszkiewicz, P.; McKinney, N., and Meyer-Arendt, K.J., 2018. Groins along the northern Yucatán coast.

Coastal erosion is a global issue, putting increasing physical and socioeconomic stresses on coastal communities. While shoreline protection structures are typically seen as potential solutions, negative environmental impacts often result. Groins, a shore-normal type of structure, can successfully impound sediment; however, improper design can lead to downdrift erosion and create hazardous rip currents. Widespread construction of groins on the northern coast of the Yucatán Peninsula is thought to have caused significant morphologic change to the shoreline, raising questions as to their effectiveness. The objective of this regional survey was to collect geodata on shoreline position and existing shoreline protection structures. Methods included (1) GPS mapping of the shoreline and groin structures along a 13-km stretch of coastline; (2) developing a classification for groin construction, condition, and attachment to the present shoreline; and (3) analyzing surface area difference 5 m immediately updrift and downdrift from each structure. Results showed that (1) since 1994, 127 additional structures were built, perhaps in response to the 128 structures detached from the shoreline that were observed in this study; (2) the 305 surveyed groins, classed into various types, had largely lost their effectiveness; and (3) greater surface area difference precedes an area of chronic erosion referenced by previous researchers. This survey provided a greater understanding of structure usage and impact on the regional scale and showed that coastal management approaches must rely upon more than groins to maintain a sustainable coastal environment.

Guevara-Guillén, C.; Shirasago-Germán, B.; Pérez-Lezama, E.L., and Obeso-Nieblas, M., 2018. Variability of chlorophyll a concentration and Halocline depth in La Paz Bay (Gulf of California, Mexico) and the relationship to Pacific large-scale climatic phenomena.

Variability of the chlorophyll a (Chl a) concentration and halocline depth in La Paz Bay were analyzed and compared against the variability of North Pacific (NP) large-scale phenomena and local winds during 1999–2009. Chl a data were obtained from satellite images, and halocline depth was obtained from in situ data. Eight large-scale phenomenon climate indices and satellite wind data were also used in this work. Chl a was processed on three timescales—interannual, mean annual cycle, and monthly time series. The halocline depth was processed as a time series. The Chl a interannual analysis revealed a high variability in the study period, with the highest concentration in 2001 and the lowest in 2005. The Pacific Decadal Oscillation (PDO) was the dominant phenomenon in this timescale. The Chl a mean annual cycle showed two concentration periods, a higher one during December to March and lower one during April to November. The El Niño Southern Oscillation (ENSO) and PDO were the most determinant phenomena in the mean annual cycle. The monthly time series also showed high variability with the highest anomalies during 2000–01 and the lowest anomalies in 2003 and 2005. The ENSO and PDO were the most influential phenomena on the monthly timescale. The halocline depth analysis revealed high and noncyclic variability, contrasting depths of 90 m during February 2002 and November 2005 with other sampling dates such as July 2001 and July 2002, when the halocline reached the surface. The NP and local winds were the main factors that influenced the halocline depth.

Mohapatra, S.C.; Fonseca, R.B., and Guedes Soares, C., 2018. Comparison of analytical and numerical simulations of long nonlinear internal solitary waves in shallow water.

This study compares the results of long nonlinear internal waves between analytical and numerical wave models in shallow water. To present the analytical solutions, the (G′/G) expansion method is applied to obtain the exact and explicit nonlinear solitary wave solutions of the generalized Gardner equation of any order in the presence of dispersive coefficient. The internal waves are demonstrated by analysing the solutions of the classical Gardner equation, modified Korteweg-de Vries equation, and Korteweg-de Vries equations from the generalized solution. The shape and characteristics of the three-dimensional solitary waves are studied by analysing different numerical results of the nonlinear analytical solutions. The Gardner equation basically behaves with the same properties as the Boussinesq equations of travelling wave solutions in shallow water. The present analytical results are compared with ones recently obtained to verify the accuracy of the peak amplitude of the velocity profiles. Then, the obtained analytical solutions have been used in the MIKE 21 BW numerical wave model to compare the internal solitary waves by imposing parametric values associated in wave speed of the solitary wave. The effects of sign of nonlinearities and dispersive coefficient on the internal solitary wave transformations are analyzed. The results show similar peak amplitudes between the present and ones recently obtained. Further, the present solution is step-profile solitary wave. The solitary wave amplitude of the analytical model is the equilibrium position of the wave displacement of the numerical model.

Schiebel, H.N.; Gardner, G.B.; Wang, X.; Peri, F., and Chen, R.F., 2018. Seasonal export of dissolved organic matter from a New England salt marsh.

The seasonality of dissolved organic matter (DOM) export from a New England salt marsh was investigated using multiple estuary transects along with laboratory plant leaching experiments. From 2001 through 2013, 35 transects of the Neponset Estuary in Boston, Massachusetts, were conducted to measure high-resolution in situ chromophoric dissolved organic matter (CDOM) fluorescence, along with other standard oceanographic parameters, via sensors incorporated into an undulating depressor wing known as the mini-shuttle. Water samples were collected during each cruise for discrete dissolved organic carbon (DOC) and CDOM fluorescence analyses. Seasonal salt marsh DOC export rates ranged from 1.1 × 10⁷ to 15 × 10⁷ mol C season⁻¹ (10–140 mol C m⁻² season⁻¹). The total export was found to be 23 ± 17 × 10⁷ mol C y⁻¹ (210 mol C m⁻² y⁻¹) with river discharge, temperature, and day length significantly affecting this rate. Results from seasonal salt marsh vegetation (Spartina alterniflora, Spartina patens, and Phragmites australis) incubation experiments showed that the leaching of DOC and CDOM from plant biomass was a rapid process occurring over several days. Sunlight exposure, biomass type (above- versus belowground biomass), and microbial activity had significant effects on DOC leaching rates from plant matter. These incubations, in conjunction with the cruise data, support the fall dump hypothesis, in which a pulse of DOC leaches from plants during the fall as marsh plants begin to senesce for winter. The long-term trend in salt marsh DOM contributions to the estuary suggested a decrease in the in situ inputs from the marsh to the estuary during the length of this study.

Messaros, R.C.; Rosati, J.D.; Buonaiuto, F.; Rasmussen, C.; Vega, A.M., and Bocamazo, L., 2018. Assessing the coastal resilience of Manasquan Inlet to Sea Bright, New Jersey: Regional sediment budget 1992–2003.

Assessing the resilience of regional coastal systems requires analysis of the short- and long-term erosion and accretion characteristics of beach material, including natural and anthropogenic sources and sinks. A regional sediment budget provides that accounting and is pivotal to successful management practices that enhance the resilience of coastal systems. The U.S. Army Corps of Engineers, New York District, updated the regional sediment budget for Manasquan Inlet to Sea Bright, New Jersey, for 1992–2003, which reflects the effects of various beach replenishment projects. The study area is approximately 33.8 km long and encompasses two inlets, mainland beaches from Manasquan Inlet to Long Branch, and a barrier-spit landform from Long Branch to Sea Bright. The previous sediment budgets represented a relatively eroded and limited source beach condition. This updated sediment budget is the first to analyze the with-project condition incorporating periodic beach nourishments/renourishments. The shore protection project consisted of an initial fill of approximately 17 Mm³ (million cubic meters) between 1994 and 2002 and additional fill/renourishment of 11 Mm³ between 2008 and 2016. Data for the sediment budget were based on volumetric change of the beach as developed from digitized, historical, aerial shoreline images as well as volumes and location of sediment replenishment (nourishment) activities in this region of the shoreline. Results from this budget indicate a net longshore transport of sediment northward from Manasquan Inlet toward Sea Bright, increasing from 106,000 m³/y just north of Manasquan Inlet to 343,000 m³/y north of Monmouth Beach. This updated sediment budget establishes a good understanding of the beach processes over time, which will enhance the ability to provide better coastal management and resilience for the northern New Jersey shoreline.

Liu, S.; Ju, Q.; Huang, W.; Hu, X.; Qi, D., and Zhong, G., 2018. Effects of crown wall and berm on wave-overtopping discharge over a seawall.

Reliable estimation of wave-overtopping discharge over a seawall is important in the crest-height design and safety assessment of coastal structures. Crown wall and berm have been widely used to reduce the wave overtopping over a seawall. According to recent literature, the influence of crown wall under breaking wave conditions has not been discussed precisely, and the reductive effect of an intermediate berm has not been clarified under nonbreaking wave conditions. In this study, 650 experiments have been conducted to investigate the influence of crown wall in breaking wave conditions and the influence of berm under breaking and nonbreaking wave conditions on the wave-overtopping discharge. New empirical equations have been derived from the analysis of experimental data to provide more accurate estimations of the reduction of wave overtopping on a seawall by crown wall or berm. The formula for crown wall is applicable under breaking waves, and formulas for berm can be applied to both break and nonbreak wave conditions. The empirical equations can be used in coastal seawall design to quantify the effects of sea-wall height, water depth on the berm, and berm width.

Ochoa-Gómez, J.G.; Serviere-Zaragoza, E.; Lluch-Cota, D.B.; Rivera-Monroy, V.H.; Oechel, W.; Troyo-Diéguez, E., and Lluch-Cota, S.E., 2018. Structural complexity and biomass of arid zone mangroves in the southwestern Gulf of California: Key factors that influence fish assemblages.

Arid zone mangroves of the southwestern Gulf of California provide ecosystem services because of their habitat heterogeneity, structure, and functions, which are important for the formation of fish assemblages. Structure, litterfall production, and leaf decomposition in three mangrove communities located at La Paz Bay, Mexico, were analyzed. Litterfall production was found to be within the range reported for the region. Leaf decomposition rate was similar between communities and species. The structural complexity and biomass of mangroves were inversely correlated with fish size, suggesting that they are key features, providing shelter and nursery for fish assemblages. Laguncularia racemosa appears to play an important role in providing greater habitat heterogeneity within mangroves, favoring fish species richness. Avicennia germinans is the most important mangrove species in the region, having the highest leaf decomposition rate, thus providing an important input of carbon to food webs and potentially stimulating fish biomass. Thus, mangroves with lower structural complexity and higher dominance of A. germinans likely have a higher potential for artisanal fisheries in the southwestern Gulf of California.

Cao, Y.; Zhen, Y.; Liu, C.; Zhang, S., and Meng, Z., 2018. Parametric study of stress concentration factors (CSFs) on tubular X-joints used in offshore platform structures.

Accurate information on stress distributions along an intersection is required for fatigue strength assessment of tubular joints subjected to cyclic loading. An X-joint is widely used on offshore platforms because its strength is very important for the safety evaluation of platforms. On the basis of ANSYS, three-dimensional elements were used to model the structure with welding seams. According to the thermo effect of the welding process, using birth–death element technology, a numerical simulation was performed for the welding process by coupling the temperature field and stress field. Considering that an annealing treatment is generally performed for joints after welding, the annealing treatment process was also simulated in this paper and the influence of it on welding residual stress was analysed. Considering the influence of welding residual stress, 81 models of X-joints with different geometric parameters and loading conditions were generated and their effects on the distribution of hot-spot stress around welding seams and stress concentration factors are discussed. Results presented in this paper provide references for the safety analysis of X-joints and thus help the design of offshore platforms for exploration and development of coastal gas and oil.

Kolokythas, G.A.; Grigoriadis, D.G.E., and Dimas, A.A., 2018. Dynamic friction coefficient in formulas of bed-load transport induced by waves over vortex orbital ripples.

Empirical formulas for the computation of bed sediment transport induced by wave propagation over sand ripples often depend on, among other parameters, the dynamic friction coefficient, μ_d, of the sand grain motion. Here, a new approach is presented for the determination of μ_d based on the physics of the interaction between flow and sediment transport. Specifically, the correlation of μ_d to the wave, ripple, and sand grain characteristics was obtained using coupled numerical simulations of the flow over the rippled bed, the bed-load transport, and the bed morphology evolution. Flow results were obtained by two different numerical methods, one for wave boundary layer flow and one for purely oscillatory flow, both based on the solution of the Navier-Stokes equations. The bed-load transport rate, which drives the bed morphology evolution, was computed using three different empirical formulas. The value of μ_d that leads to an equilibrium of the rippled bed profile after many wave periods was found to depend almost linearly on (L_r/a_o)·(h_r/a_o), where, L_r is the ripple length, h_r is the ripple height, and a_o is the wave orbital motion amplitude.

Xiong, C.; Li, Z.; Sun, X.; Zhai, J., and Niu, Y., 2018. An effective method for submarine pipeline inspection using three-dimensional (3D) models constructed from multisensor data fusion.

Submarine pipelines are of great importance to resource delivery in the oceans, but they are sensitive to a wide variety of damage and defects. In submarine resource development, life cycle monitoring is the most effective solution to ensure normal operation of pipelines, and periodic surveying and inspection are adopted as the main maintenance tasks. Recently, approaches based on acoustic surveys have been widely used for submarine inspection. However, most existing methods are based on simple parameters that cannot precisely detect the actual status of submarine pipelines under complex conditions. In this paper, to resolve the shortfalls of conventional methods, an effective method is proposed for submarine pipeline inspection based on multisensor data fusion, wherein the survey data collected by side-scan sonar, subbottom profiler, and multibeam bathymetric systems are integrated to make three-dimensional (3D) models of submarine pipelines, and a safety assessment is then conducted on the 3D models to evaluate the reliability of the pipelines at different positions. Compared with the traditional approach, the reliability of the pipeline inspection results are greatly improved, and the effectiveness and merits of the proposed method are clearly demonstrated.