Andrus, T.M. and Bentley, S.J., 2023. Capture timescale of an uncontrolled Mississippi–Atchafayala bifurcation with future lower river strategy implications. Journal of Coastal Research, 39(6), 1001–1020. Charlotte (North Carolina), ISSN 0749-0208.

The most recent and currently active delta lobe of the Mississippi River (MR) is the Atchafalaya–Wax Lake lobe, which was initiated approximately 400 years ago as a result of MR stream capture by the Atchafalaya River (AR). This capture process accelerated in the early to mid-1900s but further development was prevented by construction and operation of the Old River Control Structure (ORCS) complex in 1962. Because the initial research to warrant the construction of the ORCS was undertaken nearly 70 years ago, this study revisits the basis of the resulting predictions and evaluates how both branches could evolve moving forward both with and without ORCS controls. This study uses the Delft3D software suite to retest the capture hypothesis by accounting for complex hydrodynamic interactions from the MR/AR bifurcation to the Gulf of Mexico. A 150-year model duration was used to adequately characterize bifurcation evolution, stream capture life cycle, and long-term river management concerns. Results of modeled flow evolution with the ORCS removed indicate a rapid period of channel adjustment followed by a long and gradual increase in flow ranges and magnitudes in the AR similar to those currently in the MR. In this hypothetical scenario, the AR captures 50% of the MR very quickly (∼17 y) to become the dominant stream and then the capture rate begins to decelerate. One-hundred-fifty-year results with ORCS controls remaining unchanged reveal increased sedimentation, rising stages, and decreased stream power in the MR. Conversely, AR results indicate channel deepening, stage lowering, and increased sediment-transport efficiency. These trends suggest that although the flow split at the MR/AR bifurcation continues to be regulated by the ORCS, the geologic evolution toward capture gradually continues. This study presents a long-term view of an uncontrolled MR/AR avulsion, and capture results reiterate the ORCS's importance to socioeconomic factors such as flood control and navigation. However, results also reveal long-term sustainability concerns for the MR system associated with current ORCS flow regulation. Predictive modeling tools such as those developed in this study could be used to optimize ORCS management strategies and potentially enhance ecosystem restoration plans.

Greenheck, E.M.; Andres, M.J.; Fox, D.A.; Kiene, D.; Kreiser, B.R.; Nelson, T.R.; Peterson, M.S.; Powers, S.P.; Rider, S.J., and Slack, W.T., 2023. Gulf Sturgeon (Acipenser oxyrinchus desotoi) in the Mobile Bay Estuary, Alabama: Documentation of use outside of designated critical habitat. Journal of Coastal Research, 39(6), 1021–1043. Charlotte (North Carolina), ISSN 0749-0208.

Gulf Sturgeon (GS) are an anadromous, federally threatened subspecies of Atlantic Sturgeon that feed primarily in estuarine and marine systems in the northern Gulf of Mexico from October to April. All extant natal river systems and adjacent estuarine and marine environments were designated as critical habitat for GS in 2003, excluding the Mobile River Watershed because of lack of data indicating an extant spawning population at the time of listing. Previous studies had identified that GS from river systems east of Mobile Bay use habitats within the Mississippi Sound, suggesting GS must at least traverse Alabama waters. Therefore, this study's objective was to quantify the use of the Mobile Bay Estuary by GS. GS were acoustically tagged in all extant natal river systems and detected by an array of receivers deployed in the Mobile Bay Estuary during 2016–21. A total of 210 adult and subadult GS from western (n = 97) and eastern (n = 113) river systems were detected in the Mobile Bay Estuary for up to 4 months, with 110 individuals detected from 2 to 6 years during the monitoring period. The sustained use of the Mobile Bay Estuary by GS from western and eastern river systems strongly indicates that Alabama's waters are suitable habitat despite extirpation of the natal spawning population in the Mobile River Estuary. Foraging in the Mobile Bay Estuary is probable because previous sediment and benthic macroinvertebrate sampling in this system indicated relatively low-percent sand content and high polychaete richness, which are characteristic of foraging habitats previously identified in the Pascagoula River delta. The Mobile Bay Estuary is not designated as critical habitat for GS; however, this study indicates nonanomalous use of this habitat by GS during the foraging period, so inclusion of this system under the critical habitat designation should be considered.

Cayer, D. and Hatvany, M., 2023. Complexity, variance, and nonlinearity: A multisite, multiseasonal study of tidal marsh sedimentation processes in the St. Lawrence Estuary, Canada. Journal of Coastal Research, 39(6), 1044–1067. Charlotte (North Carolina), ISSN 0749-0208.

A review of the international literature demonstrates the high potential of intertidal marshes for sediment sequestration and growth over time. Surprisingly few studies, however, discuss the sediment pathways that occur both seasonally and annually or the magnitude of such transits. Using a multifactorial approach that accounts for asymptotic evolution, this study examines and compares four marsh sites in the maximum turbidity zone of the St. Lawrence Estuary. The aim is to determine the role of intrinsic and extrinsic factors, ecogeomorphologic feedbacks, and coastal configuration on sediment dynamics. The hypothesis is that multiagency results in nonlinear evolution trends that are site specific. The methodology comprises interannual and intersite surface-height measures, sediment concentration values, tidal inundation frequency, relative sea-level data, and a weather activity index. The results reveal variable sediment deposition rates and surface-height evolution across the marsh profile over multiple seasons and between sites. They also conform with the understanding of asymptotic evolution and illustrate a multifactorial agency driving current dynamics. As hypothesized, the evolution of the studied marshes was highly variable and nonlinear across time and space, demonstrating complex sediment pathways. Recognition of this variability brings into question the generalizability of tidal marsh dynamics in large systems. Ultimately, modelling the trajectories and predictability of future marsh evolution in large systems such as the St. Lawrence Estuary requires a multifactorial approach over multiple seasons and at multiple sites.

Marland, F.C.; Kjerfve, B., and Smith, J.S., 2023. Emergent sandy barriers formed Sapelo Island (Georgia, U.S.A.) during Heinrich events and in the Holocene. Journal of Coastal Research, 39(6), 1068–1081. Charlotte (North Carolina), ISSN 0749-0208.

Sapelo Island's core consists of five separate barrier islands corresponding to five Heinrich events, H5–H1. During the present interglacial rise of the sea, Holocene barriers (H0) were attached to the most recent paleo-barrier, H1. All barriers have a recurved spit with an intervening backbay tidal marsh. Each barrier is composed of several dune ridges. Beach ridge editions were not formed at their present locations. Sand and other materials emerged from below sea level on the shelf in transgressive, elevated H seas and in the last post-glacial rise of the Holocene interglacial. Fourteen spurious increases of higher sea levels of warmer water in Dansgaard-Oeschger (D-O) events were followed by cooling H intervals with extreme waves during gales, hurricanes, and possibly tsunamis. Deltaic surplus materials on the shelf rolled shoreward. Storms drove deposits onshore in predominant wave episodes of overwash. Pliocene and Pleistocene sand surpluses on the continental shelf in relict river channels and deltas were and are source deposits. The preserved varved chronology is based on analyses of pollen and microfossils from Lake Tulane, Florida. Lake Tulane provides a continuous timeline of comparable radiocarbon ages to Sapelo. Both sites are considered coeval. Overwash deposits on the dry sand beach above average tides were forerunners of dune formation. After storms, backshore sand was trapped within strandlines of Spartina marshwrack. Materials caught in the straw mulch on the dry sand produced aeolian dune ridges during windswept Nor'easters. High dunes grew from low and coalesced into a series of barriers to form Sapelo Island.

Liu, H.; Deng, J., and Wu, J., 2023. Benthic turbulence affected by various wave conditions in the surf zone. Journal of Coastal Research, 39(6), 1082–1093. Charlotte (North Carolina), ISSN 0749-0208.

To understand turbulence and associated sediment transport in the surf zone, it is of crucial importance to explore the effect of wind waves consisting of non-breaking (low) and breaking (moderate) waves. A bottom-mounted instrumental tripod was deployed on a dissipative beach in the surf zone in the south China coast to examine the relative importance of wave-induced turbulence and bed-induced turbulence in the different hydrodynamic conditions. The data were collected in 0.5–3 m water depth from 20–29 July 2016. During the survey, a tropical storm attacked the nearby coast from 26–27 July. The Synchrosqueezed Wavelet Transform method was used to decompose the wave and turbulent data. The results show that the bed-generated turbulence dominated with weak wind waves during neap tide. The Reynolds shear stresses and turbulent kinetic energy was almost vertically uniform in this period. On the contrary, the degree of turbulence anisotropy became weak and various turbulence properties or scaling (e.g., Reynolds shear stresses, turbulent kinetic energy, dissipation rate, Froude-scaled turbulence) enhanced significantly with moderate waves during spring tide and storm period. The turbulent properties increased in magnitude away from the bed beneath waves breaking. The observations suggest that breaking waves are the dominant source of turbulence under strong onshore winds, which are significant and may dominate over bottom boundary layer process in the surf zone.

Ghosh, S., 2023. Reproductive biology and feeding habits of razorbelly scad, Alepes kleinii (Bloch, 1793), in the northeastern Arabian Sea. Journal of Coastal Research, 39(6), 1094–1104. Charlotte (North Carolina), ISSN 0749-0208.

Alepes kleinii is subject to a commercial fishery in the northern Indian Ocean. The present study provides new information on the diet and reproductive biology of this species, based on the examination of 1109 specimens caught by gillnet off the coast of Veraval (north-eastern Arabian Sea). These samples ranged from 8.6–16.9 cm fork length (L_F), and the sex ratio (male:female) was 1:1.45. Females and males reached sexual maturity at 12.25 cm and 12.57 cm L_F, respectively. A. kleinii spawn throughout the year, though the peak spawning period was January–March. Monthly percentage of spawning capable individuals ranged from 11.8–60.4% (females) and 12.5–52.6% (males). The gonadosomatic index of females varied from 2.55–6.93, and absolute batch fecundity ranged from 30,653 to 70,275 eggs. Egg diameter (ranging from 230–720 µm) distribution was bimodal with the dominant peak at 601–700 µm, indicating group-synchronous ovarian development. In relation to the diet, A. kleinii <10.0 cm L_F were zooplanktivorous, with zooplanktonic crustaceans the predominant prey category; whereas crustaceans were the principal diet of larger (≥10.0 cm L_F) individuals followed by juvenile teleosts. Variations in feeding preferences were insignificant with respect to three climatological seasons (18.14%–18.50%) and two length classes (17.73%). Feeding intensity was low, although it increased with fish length, and was at a minimum during the peak spawning months.

Windom, H.L. and Palmer, J.D., 2023. Fluvial transport of suspended sediments in the Apalachicola Basin to Apalachicola Bay: Implications to salt marsh sustainability. Journal of Coastal Research, 39(6), 1105–1113. Charlotte (North Carolina), ISSN 0749-0208.

Modifications of the Apalachicola, Chattahoochee, and Flint (ACF) River Basin, including construction of dams, reservoirs, and navigation channels, were made prior to 1960. This, along with increased water withdrawal occurring primarily in Georgia and Alabama to meet increasing agriculture and municipal water supply demands, has significantly affected the fluvial transport of water and suspended sediments to Apalachicola Bay, located along the Gulf coast of Florida. Using suspended sediment load (SL) data from the most down-basin U.S. Geological Survey gauging, suspended-sediment input to the Apalachicola Bay during the 21st century was estimated to be 0.51 metric tonnes per year. At the present time, this supply is sufficient to maintain the vertical integrity of Bay salt marshes at the rate of sea-level rise. Based on historic SL data for river reaches in the lower ACF Basin, the suspended-sediment discharge to Apalachicola Bay will likely decline.

Nabhan, A.; Widinly, N.; Memesh, A.; Khorsheed, M.; El-Sorogy, A.S., and Tawfik, M., 2023. Sedimentological and geomorphological characteristics of Jabal Kudumbul Island, southeast Red Sea, Saudi Arabia. Journal of Coastal Research, 39(6), 1114–1123. Charlotte (North Carolina), ISSN 0749-0208.

A marine geological survey of the Quaternary volcanic island of Jabal Kudumbul in the rifted southeastern Red Sea in Saudi Arabia has been conducted for the first time. The survey aimed to document sedimentological and geomorphological characteristics from sample collection and interpretation of high-resolution satellite images taken in the last decade. Beach, sand dune, and sand sheet sedimentary facies types were identified. The volcanic mountain in the western zone of the island and the low-lying sandy shorelines in the eastern zone represent the main geomorphic landforms related to wave and current processes in the study area. The volcanic cone showed three volcano-stratigraphic facies units: basalt rocks, phreatomagmatic lapilli tuff, and vesicular basalt/scoria, indicating that they might have been formed during eruption and interaction between rising magma and shallow seas. The coastline constantly changes over time due to longshore processes and spring tides. A suite of complex wind, wave diffraction, longshore current, and biological processes and episodic synrifting in the area played dominant roles in facies and landscape creation and the overall development of Jabal Kudumbul Island. These findings provide important information for future studies on the arid islands in the Red Sea region beyond modern surficial deposits.

Vasseur, P.L.; Collins, S.A., and Selman, W., 2023. Effects of tropical cyclones and other severe weather events on Reddish Egret (Egretta rufescens) populations in Louisiana, U.S.A. Journal of Coastal Research, 39(6), 1124–1136. Charlotte (North Carolina), ISSN 0749-0208.

Tropical cyclones (i.e. tropical depressions, tropical storms, and hurricanes) and other extreme weather events directly impacting Louisiana from 2016–21 were examined to determine their effects on adult Reddish Egrets equipped with satellite transmitters in SE (n = 11) and SW (n = 14) Louisiana. Fourteen tropical cyclones (six hurricanes, five tropical storms, one tropical depression, and two extratropical cyclones) impacted Louisiana during the study, and telemetry data were reviewed immediately on and around (±1 day) the arrival of each storm to monitor any movements and individual survival. As many as nine of 25 (36%) transmittered Reddish Egrets presumably died from the direct impacts of five tropical cyclones; seven of nine mortalities were associated with three major hurricanes. Mortality was presumed based on stationary GPS fixes for multiple days or the termination of data transmission following a storm. All mortalities were presumed, as no carcasses were recovered. Previous telemetry studies reported Reddish Egrets often survived intense tropical cyclones and direct impacts were not appreciable at the population level. Yet, more than one-third of the transmittered birds in the sample population potentially died from storm-related impacts, and the population may have declined drastically, assuming some unmarked individuals also likely died. Because the Reddish Egret is restricted to coastal habitats, the species appears to be particularly vulnerable to tropical cyclone effects. If predictions of increased frequency and intensity of tropical cyclones by the end of this century are accurate, these storms pose a significant threat to Reddish Egret populations. With accelerated loss and degradation to suitable coastal habitats, protection and restoration of key foraging and nesting sites for sensitive species similar to the Reddish Egret are needed in Louisiana and other disturbance-prone areas along the Gulf Coast.

Manjunathan, M.; Ravikumar, T.; Chandran, S.; Neethiselvan, N.; Jawahar, P.; Arisekar, U., and Karthy, A., 2023. Catch efficiency and economic analysis for traditional fishing gear (troll lines) operated along the Coromandel and Gulf of Mannar coasts (southeast India). Journal of Coastal Research, 39(6), 1137–1145. Charlotte (North Carolina), ISSN 0749-0208.

This study evaluated the effects of three different J hook types, single hook no. 6, double hook no. 6, and triple hook no. 8, on catch rate, catch composition, and economics of two traditional troll-line methods used along the southeast coast of India. Traditionally, the hand- and leg-held troll line has been used in the Gulf of Mannar (GoM), and the outrigger boom-held method has been used on the Coromandel (CoM) coast. The studies were conducted at fortnightly intervals between June 2020 and January 2021. The overall catch rate (no. h²¹) was found to be highest with the double hook (0.6 fish h²¹) and lowest with the triple hook (0.04 fish h²¹) on the CoM coast, while the single hook (0.34 fish h²¹) and triple hook (0.02 fish h²¹) showed the highest and lowest catch efficiency along the GoM coast, respectively. The catch composition was constituted by Scomberomorus commerson (36%), Auxis thazard (18%), Euthynnus affinis (16%), Caranx ignobilis (13%), Thunnus albacares (9%), Scomberomorus guttatus (7%), Coryphaena hippurus (0.8%), and Istiophorus platypterus (0.2%) in the GoM, while it was Thunnus albacares (45%), Euthynnus affinis (18%), Auxis thazard (14%), Istiophorus platypterus (7%), Coryphaena hippurus (6%), Acanthocybium solandri (5%), Scomberomorus commerson (3%), and Caranx ignobilis (2%) on the CoM coast. The chi-square test showed a significant correlation between hook type and fish composition (χ² = 9650.6, df = 16, p < 0.05). The current study demonstrated a net profit improvement of 3313 rupees/trip at GoM and 2093 rupees/trip at CoM. The benefit-cost ratio (B:C) for GoM and CoM was calculated to be 1.84 and 1.76, respectively.

de Freitas, A.S.; Oliveira Santos, A.D.; dos Santos, R.F.; Nascimento, M.T.L.; da Fonseca, E.M.; Félix, L.C.; Bila, D.M.; Aguiar, V.M.C., and Baptista Neto, J.A., 2023. Chemical and biological indicators of environmental pollution in the Canal do Cunha (Guanabara Bay, Rio de Janeiro, Brazil): Analysis and determination of toxins. Journal of Coastal Research, 39(6), 1146–1157. Charlotte (North Carolina), ISSN 0749-0208.

Pollutants and biological data were assessed in surface sediments from an urbanized and hypereutrophic bay in Brazil. The surface sediment samples contained coarse to fine grains. The samples were analysed using four tools that followed standard methodologies. Pollutants were observed in several sediment samples, as was observed with the pseudototal trace elements. Dinoflagellate cysts showed an indication of a eutrophic environment with the presence of L. machaerophorum. On the other hand, the Vibrio fischeri bioassay demonstrated high toxicity in this area. The obtained data demonstrate the high level of pollution in the area due to a high input of untreated sewage and a large number of industries close to the collection points. Therefore, the Canal do Cunha basin can be considered an outflow area for different pollutant residues being transported into Guanabara Bay.

Chen, S.; Jiang, C.; Wang, Z.; Zhang, F.; Xia, J., and Li, F., 2023. Intelligent prediction method for linear wave load based on deep neural network. Journal of Coastal Research, 39(6), 1158–1169. Charlotte (North Carolina), ISSN 0749-0208.

To more efficiently and accurately calculate the linear wave load response of a ship at any section position under different speeds, wave periods, wave heights, and wave directions, a linear wave load intelligent prediction (LWLIP) method is established by combining the experimental design, data processing and analysis, strip theory, and deep neural network methods. Taking a ship as an example, the LWLIP analysis was carried out, and the application of the LWLIP method was verified. The results show that, under any sea conditions, the LWLIP method is an alternative to the strip theory program for wave load prediction with high accuracy, it expands the calculation limitations of strip theory, such as section position and wave angle, and it improves the calculation efficiency. The prediction time of the model is 1 ms. The results of this study are of great significance for the rapid assessment of ship global wave loads.

Altinay, Z.; Morris, L.L., and Reams, M.A., 2023. Information needs of coastal residents in Louisiana, U.S.A.: Implications for risk communication. Journal of Coastal Research, 39(6), 1170–1179. Charlotte (North Carolina), ISSN 0749-0208.

This study aims to address the gap between communication practices and adoption of hazard-mitigation behavior in a deltaic land that experiences chronic coastal hazards, including storm surges and shoreline erosion. Focusing on Louisiana's coastal crisis, first, an online questionnaire was distributed to identify hazard mitigation patterns and information needs of a subset of southern Louisiana residents. A follow-up focus-group discussion sought to delve deeper into residents' experiences with community communication practices as well as the obstacles with dissemination of hazard-mitigation information to nontechnical audiences. Participants recommended the establishment of stronger public-private partnerships, increased use of visual information, and the necessity of providing clear and comprehensive details regarding funding and financial assistance programs to communicate hazard mitigation strategies. Findings provide a starting point for building local knowledge through extension engagement related to the delivery of hazard-mitigation information and discuss how to engage in proactive outreach methods to raise awareness about risk and hazard mitigation for both technical and nontechnical audiences. It combines the theoretical framework of community resilience with principles of communication. Results of this study contribute to an understanding of the barriers to household-level mitigation actions within the community; provide community feedback for extension agents and state and local officials; and suggest discussion points in the context of the Louisiana Coastal Master Plans.

Wang, M.-F., 2023. The application of marine customs, traditions, and beliefs into Hakka culture-based creative product design. Journal of Coastal Research, 39(6), 1180–1193. Charlotte (North Carolina), ISSN 0749-0208.

The government and civil groups in Taiwan have long dedicated themselves to the design of creative Hakka products. Although there has been some progress, originality and distinctiveness are lacking when it comes to the use of Hakka cultural elements and product attributes. The design model for the present study is based on national and international literature that analyzed symbolism, metaphysics, three layered culture, reverse-triangular cultural space, Zen aesthetics, etc., and honest feedback based on the actual feeling toward the culture. The difference of Laozi's philosophy in this model can contribute to the different cognition of the culture in various aspects in the time axis and provide diverse views of the culture. Therefore, this study proposed the theory of cultural realism and virtualism by introducing philosophical and mathematical methods and applying the concepts of realism and virtualism to deconstruct and construct cultural elements and implement the design of marine culture and belief in Hakka cultural-based creative products. Therefore, by constructing and optimizing the design processes and incorporating the oceanic culture and religious beliefs, it is possible to increase the value of creative Hakka products, leading to better understanding of the Hakka culture and greater self-identification, it contributes to the multiple theories and thinking modes of design education.

Stalter, R. and Lonard, R.I., 2023. Biological flora of coastal mid- and high marshes: Juncus roemerianus Scheele. Journal of Coastal Research, 39(6), 1194–1205. Charlotte (North Carolina), ISSN 0749-0208.

Juncus roemerianus Scheele, black needlerush, is a rhizomatous salt marsh species that often forms dense monotypic stands in the mid- and high marshes along the mid- to SE Atlantic coastline and southward to the upper Texas coast in the United States. A dense rhizome complex allows this taxon to reproduce asexually and to exclude potential competitors. Juncus roemerianus has numerous ecosystem functions, including carbon sequestration, control of erosion, protection from storm surges, and as a nursery for numerous marine organisms. This species tolerates a range of salinity generally less than 5.0 ppt to as high as 35 ppt in a few marshes. Juncus roemerianus is noted for its high levels of productivity in below- and aboveground biomass values. Black needlerush is highly sensitive to oil pollution, much more so than its closest associate in the salt marsh community Sporoblus alterniflorus. Juncus roemerianus plays an important role in revegetating disturbed marshes and has a potential role for preventing the re-invasion of Phragmites australis in newly created marshes.

From 25 to 27 April 2023, the Institution of Civil Engineers (ICE) hosted again the Coasts, Marine Structures, and Breakwaters conference (CMSB)—or Breakwaters for short, as it is sometimes named—at the Marriott Hotel in Portsmouth, UK. The CMSB conference series, held by the ICE for more than 30 years, is one of the leading international forums for the presentation of the latest developments in coastal and maritime engineering. Its previous edition, already the 11th conference in the series, took place in Liverpool from the 5 to 7 September 2017, and set the bar once again very high for its successor. The conference focused on the latest developments across maritime engineering topics from coasts to ports and waterfronts to breakwaters, while concentrating on the full spectrum of research, study, design, construction, and operations. In view of the ever-increasing attention on climate change, an additional spotlight was also placed on how resilience and adaptability are being addressed by the maritime sector. This communication reports on the 2023 CMSB conference, some of the insights and impressions gathered at the conference by the author, and the relevance of the presented material to the tackling of some of the important issues facing our coastal communities and broader environment today.