Stretch Of Beach Research Articles

Elevated Calf Mortality and Long-Term Responses of Wild Bottlenose Dolphins to Extreme Climate Events: Impacts of Foraging Specialization and Provisioning

As demands for wildlife tourism increase, provisioning has become a popular means of providing up-close viewing to the public. At Monkey Mia, Shark Bay, Australia, up to five adult female Indo-Pacific bottlenose dolphins (Tursiops aduncus) visit a 100 m stretch of beach daily to receive fish handouts. In 2011, a severe marine heatwave (MHW) devastated seagrass and fish populations in Shark Bay. Offspring survival declined precipitously among seagrass specialists (dolphins that forage disproportionately in seagrass habitat). As all provisioned dolphins at the site are seagrass specialists, we examined how provisioned and non-provisioned seagrass specialists responded to the MHW. Using 27 years of data we compare habitat use, home range size, calf mortality, and predation risk between provisioned and non-provisioned females and their offspring before and after the MHW. Our results show that provisioned females have extremely small home ranges compared to non-provisioned females, a pattern attributable to their efforts to remain near the site of fish handouts. However, weaned offspring (juveniles) born to provisioned females who are not provisioned themselves also had much smaller home ranges, suggesting a persistent maternal effect on their behavior. After the MHW, adult females increased their use of seagrass habitats, but not their home range size. Provisioned females had significantlylowercalf mortality than non-provisioned females, a pattern most evident pre-MHW, and, in the first 5 years after the MHW (peri-MHW, 2011–2015), calf mortality did not significantly increase for either group. However, the ecosystem did not recover, and post-MHW (2016–2020), calf mortality was substantially higher, regardless of provisioning status. With few survivors, the impact of the MHW on juvenile mortality post-weaning is not known. However, over three decades, juvenile mortality among offspring of provisioned vs. non-provisioned females did not statistically differ. Thus, the survival benefits accrued to calves in the provisioned group likely cease after weaning. Finally, although shark attack rates on seagrass specialists did not change over time, elevated predation on calves cannot be ruled out as a cause of death post-MHW. We discuss our results as they relate to anthropogenic influences on dolphin behavioral plasticity and responses to extreme climate events.

Species determination based on head scutes, carapace, and plastron of turtle hatchlings at Boom Beach, Banyuwangi

A comprehensive study on the determination of species is important for the turtle conservation program. The external characteristics of turtles were identified based on the pattern of the head scutes, carapace and plastron. This study aimed to investigate the dead hatchling species at Boom Beach, Banyuwangi. Boom Beach is a 3 km stretch of beach in northeast Banyuwangi. We investigated 15 dead hatchlings from 4 different nests. Patrols were carried out all night and morning on the surface of the nest and excavated to collect dead hatchlings. All hatchlings were cleaned of epibion and dried to avoid reflection. The hatchlings were placed on a white table and photographed with a digital camera (Nikon D3100) from above. Figures were taken at a distance of 1 m to reduce the effects of visual distortion. As a result, the pattern of head scutes consisted of more than one pair of prefrontal scales; carapace consisted of six lateral scutes and six vertebral scutes; and plastron consisted of four intramarginal scutes with pores, respectively. It can be concluded that all the dead hatchlings were species of olive ridley turtle (Lepidochelys olivacea).

VARIAÇÃO DA LINHA DE COSTA NO LITORAL LESTE DO ESTADO DO CEARÁ: O CASO DA RESEX DA PRAINHA DO CANTO VERDE

A zona costeira, área de extrema dinamicidade devido à interação entre os sistemas marinhos e continentais e aos também fenômenos climáticos, tem passado por consequentes alterações em decorrência das mudanças climáticas cada vez mais recorrentes e severas, implicando diretamente na linha de costa, seja na forma de erosão, seja na progradação. Dessa forma, utilizando-se das metodologias associadas às técnicas de geoprocessamento, foi possível verificar que nos últimos 13 anos o trecho de praia que compreende a Resex da Prainha do Canto Verde, localizada no litoral leste do Ceará, apresentou taxas de erosão que variamentre -4,14 m/ano e -2,33 m/ano (EPR) e de -3,66 m/ano a -1,77 m/ano (LRR). Em termos totais, isso representa um recuo da linha de costa que variou entre pouco mais de 50 m, no máximo, e mínimo de 23 m de acordo com as estatísticas utilizadas pela extensão DSAS.
 Palavras-chave: erosão costeira, linha de costa, gerenciamento costeiro.

Marine debris on two Arctic beaches in the Russian Far East

In August 2005, marine debris was counted on two Arctic beaches in the Russian Far East. On the north coast of the Chukchi Peninsula east of Kolyuchin Bay, a beach stretch of ca. 2.4 km held a total of 736 items, 0.024 items m‑2, while no more than 0.0011 items m‑2, 12 items in total, were found on a beach stretch of ca. 1.2 km on southern Wrangel Island. The likely explanation for this difference is that the area around the mainland beach is ice-free for a longer period each year, but a contributing factor may be that late spring ice movement removed plastic from the beach on Wrangel Island. The language on the few items with identifiable labels was for the most part Russian or English, making the Chukchi Sea a possible source region. Beaches at the same latitude in the Atlantic may hold more debris on account of the higher human population density, more shipping and transport of floating debris unhindered by a narrow strait that is ice-covered much of the year. Fishing gear blown across the tundra is suggested as a potential threat to reindeer and other terrestrial wildlife.

What Happens to a Mediterranean Microtidal Wave-dominated Beach During Significant Storm Events? The Morphological Response of a Natural Sardinian Beach (Western Mediterranean)

Trogu, D.; Buosi, C.; Ruju, A.; Porta, M.; Ibba, A., and De Muro, S., 2020. What happens to a Mediterranean microtidal wave-dominated beach during significant storm events? The morphological response of a natural Sardinian beach (western Mediterranean). In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 695-700. Coconut Creek (Florida), ISSN 0749-0208.The short-term effects of storm events on the coastline morphology of natural, microtidal, wave dominated beaches located in the western Mediterranean are still poorly documented. Since one of the most visible consequences of a warming climate is an increase in the intensity and frequency of extreme weather conditions, it appears important to know the response of natural and urban beaches to these storm events.The spatial shoreline variability of a natural Sardinian beach was assessed in our study, based on video camera monitoring data from August 2013 to August 2015 along a 0.3 km stretch of sandy beach. This methodology has been applied in the SW coastal sector of Sardinia where severe storm events mainly related to southwesterly winds (about 50 km/h on average) can induce important morphological changes. These include shoreline retreat/progradation, erosion, beach rotation, reconfiguration of nearshore bars and the deposition of significant seagrass beach-cast litters. Our study showed an erosion and a consequent accretion of the studied beach of about 20 m in two days after the event (SW wind and waves) as a result of the deposition of the Posidonia oceanica beach-cast litter. This morphological response induced by storm events is crucial for coastal managers to plan beach management (for example beach cleaning practice), to prevent coastal risk and to understand the importance of seagrass berm deposition in the formation of natural Mediterranean beaches.

Marine litter on the Albanian coastline: Baseline information for improved management

Beach litter surveys represent a fundamental tool for monitoring marine litter pollution in the marine environment and have been used worldwide to quantify the amounts of litter deposited on the coastline and detect its sources. This study investigated the abundance, composition and sources of marine litter stranded on five beaches located at the bay of Durres and the Bay of Lalzi in Albania. During April 2018, a total of 3,321 marine litter items were collected, classified and recorded. Within this study the mean litter density was found to be 0.14 items/m2 and 333 items/100m stretch of beach. The sites investigated differed in terms of human-induced pressures with 2 sites being classified as semi-urban; 2 sites as urban and 1 as semi-rural. Artificial/anthropogenic polymer materials accounted for the majority of marine litter items found, with a percentage of 65%. The most abundant type of items was glass and ceramic fragments accounting for 19.7%, followed by cigarette butts and filters accounting for 17.9% of all litter collected. The vast majority of litter items (58.5%) originated from shoreline sources including poor waste management practices, tourism and recreational activities. Single-use plastics (SUPs) accounted for 48% of all items recorded ranging from 16.8% to 69.1% for the different beaches.

Mortality of the Atlantic ghost crab Ocypode quadrata (Fabricius, 1787) due to vehicle traffic on sandy beaches: A road ecology approach

Sandy beaches are not roads, but they have been used as such worldwide, threatening endemic fauna such as ghost crabs (Crustacea: Ocypodidae). The objective of the present study was to identify the spatial factors influencing the incidence of ghost crabs (Ocypode quadrata) killed by vehicles. This study included a systematic study of carcasses with clear signals of crushing by cars on beaches with distinct urbanization levels and on dirt roads crossing low-urbanized beach stretches. Predictive variables (e.g., tyre tracks on the sand, proxies of urbanization, distance from coastal lagoons and beach width) were obtained for the kill points and random points. Generalized linear models with binomial distributions showed that the number of tyre tracks nearby (positive correlation) and indicators of urbanization in the environment (negative correlation) were the main variables explaining ghost crab kills on the beach. Similarly, the likelihood of finding crabs killed by vehicles on the dirt road was associated with the areas with the densest ghost crab populations (higher beach width and low-urbanized areas). Therefore, as an important conservation strategy and mitigation action, vehicle traffic must be severely controlled mainly on low-urbanized beaches, both on the sand and dirt roads crossing natural beach vegetation.

Short-term movement patterns, population estimates and breeding biology of an island endemic bird, the Tristan Thrush

The Tristan Thrush Turdus eremita is the only land bird that survived human colonisation of the main island of Tristan da Cunha and is listed as “Near Threatened”. Population estimates are confounded by the thrushes’ inquisitive and gregarious nature as well as limited information on their movements. We report the first measures of nest densities on Nightingale Island: 6 nests·ha-1 in Phylica arborea woodland and 4–5 nests·ha-1 in tussock habitat, which suggests that the population is approximately double the previous estimate. At Inaccessible Island, we individually color ringed 110 thrushes over two months to track their short-term movements and estimate the local population size. Individuals moved up to 950 m along the coast, but 96% of resightings were < 100 m. A Bayesian data augmentation approach estimated that some 260 thrushes visited the core study area, a 200-m stretch of cobble and boulder beach where birds come to drink, bathe and forage. This result suggests that the population on Inaccessible Island also is substantially larger than reported previously. We estimate the total population to be 8000–15,000 Tristan Thrushes. The main need is a population estimate for the nominate subspecies on the main island of Tristan.

Comparison of beach temperatures in the nesting range of Kemp’s ridley sea turtles in the Gulf of Mexico, Mexico and USA

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 40:31-40 (2019) - DOI: https://doi.org/10.3354/esr00977 Comparison of beach temperatures in the nesting range of Kemp’s ridley sea turtles in the Gulf of Mexico, Mexico and USA Elizabeth M. Bevan1,*, Thane Wibbels1, Donna Shaver2, Jennifer Shelby Walker2, Francisco Illescas3, Javier Montano4, Jaime Ortiz4, Jaime J. Peña4, Laura Sarti5, Blanca M. Z. Najera5, Patrick Burchfield4 1University of Alabama at Birmingham, Department of Biology, Birmingham, AL 35249, USA 2National Park Service, Padre Island National Seashore, Division of Sea Turtle Science and Recovery, Corpus Christi, TX 78480, USA 3CDEN, Ciudad Madero, Tamaulipas, C.P. 89514, Mexico 4Gladys Porter Zoo, Brownsville, TX 78520, USA 5CONANP, Ciudad Victoria, Tamaulipas, C.P. 87000, Mexico *Corresponding author: bevan.em@gmail.com ABSTRACT: Rising environmental temperatures associated with climate change can adversely affect sea turtles whose hatchling sex determination is temperature-dependent. One hypothetical response of sea turtles to near-future elevated temperatures is a shift in nesting distribution to maintain suitable thermal conditions. Assessing sea turtle responses to climate warming involves evaluating (1) how temperatures will be altered, (2) a species’ capacity to respond to changes, and (3) whether responses can mitigate the impacts of warming. We evaluated sand temperatures across nesting habitat of the Critically Endangered Kemp’s ridley sea turtle Lepidochelys kempii in the western Gulf of Mexico. Most nesting now occurs on a 30 km stretch of beach in Tamaulipas, Mexico, but was historically more widely distributed. Applying conservative projections, we assessed whether a shift in the epicenter of nesting to the northern extent of the present distribution would maintain incubation temperatures below lethal levels and suitable to produce hatchlings of both sexes. Coupling temperature measurements with known impacts of temperature on the reproductive physiology of L. kempii, we predict that northern beaches will initially support the production of mixed sex ratios. However, the rapid rate of warming and long generation time for L. kempii make a shift in nesting unlikely to ultimately mitigate the effects of elevated temperatures on hatchling sex ratios and mortality. The limited thermal profile of the restricted L. kempii nesting range, and temperature-dependent sex determination, make this sea turtle particularly vulnerable to climate change. This vulnerability provides the opportunity to gain insights on strategies for the survival of thermally sensitive species in a warming world. KEY WORDS: Lepidochelys kempii · Climate change · Temperature-sensitive sex determination · TSD · Incubation temperatures · Nesting range · Gulf of Mexico Full text in pdf format PreviousNextCite this article as: Bevan EM, Wibbels T, Shaver D, Walker JS and others (2019) Comparison of beach temperatures in the nesting range of Kemp’s ridley sea turtles in the Gulf of Mexico, Mexico and USA. Endang Species Res 40:31-40. https://doi.org/10.3354/esr00977 Export citation Mail this link - Contents Mailing Lists - RSS Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 40. Online publication date: October 02, 2019 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2019 Inter-Research.

Unusual Beach Changes Induced by Hurricane Irma with a Negative Storm Surge and Poststorm Recovery

Cheng, J. and Wang, P., 2019. Unusual beach changes induced by Hurricane Irma with a negative storm surge and poststorm recovery. Journal of Coastal Research, 35(6), 1185–1199. Coconut Creek (Florida), ISSN 0749-0208.The coast of west-central Florida, facing the Gulf of Mexico, experienced Hurricane Irma with a negative surge of 1.1 m and a highly oblique northerly approaching wave in September 2017. This unusual hydrodynamic condition provides an opportunity to investigate the effect of surge and incident wave direction on morphology changes. Beach profiles, spaced at 300 m apart, along a 15-km stretch of beach were surveyed 2 weeks prior to the passage of Hurricane Irma and 1 week after and continued for up to 5 months after the passage to obtain Irma-induced erosion as well as post-Irma recovery. Owing to the occurrence of negative surge, the profile volume of the dune field remained mostly stable. The majority of beach erosion occurred below mean sea level, with a considerable amount of sediment transported seaward of the depth of closure. This is opposite to the conservation of beach profile volume above depth of closure under several earlier storms with a positive surge. The alongshore variation of overall beach profile volume erosion demonstrates a southward decreasing trend, due to a southward decreasing wave height as controlled by the northerly incident wave. After the passage of Irma, minor beach volume recovery occurred during the calm period of the fall season. Opposite to the typical erosive beach in winter, the most substantial beach accretion and onshore bar movement were observed during the following peak winter season as beach/bar evolved toward equilibrium. The profile volume in the dry beach region experienced a complete recovery in the first 5 months after Hurricane Irma. Shoreline change is a valid proxy for beach volume change during both the erosive and the recovery phase of Irma. The systematically measured beach profiles provide a solid dataset to calibrate process-based models to study beach morphodynamics.

An evaluation of nest predator impacts and the efficacy of plastic meshing on marine turtle nests on the western Cape York Peninsula, Australia

Nest predation is considered to be one of the most significant biotic threats to marine turtle populations globally. The introduction of feral predators to nesting beaches has dramatically increased nest predation, reaching near total egg loss in some regions. We monitored a 48 km stretch of beach along western Cape York Peninsula, Australia, from June – November 2018. We recorded a total of 360 nests comprising 117 flatback and 243 olive ridley nests. We installed plastic meshing (90 cm × 100 cm) on 110 olive ridley nests (45.2% of total olive ridley clutches laid) within the study area. We classified all nest predation attempts into three categories: complete, partial, or failed predation events. In total, 109 (30.2%) of all marine turtle nests were depredated by a variety of predators, including feral pigs, dingoes, goannas, and humans. The addition of plastic meshing reduced the likelihood of dingoes gaining access to eggs, but not goannas or feral pigs. Further, we found no difference in the proportion of hatchling emergence between meshed and un-meshed nests. Additionally, while hatchling emergence was reduced in nests that had been partially depredated, these nests still produced live hatchlings and contributed to recruitment. The success of particular predator control methods is often predator, and/or regionally, specific. Our findings highlight a thorough understanding of predator guilds and their relative impacts is required to deploy targeted and predator-specific strategies to maximize conservation results. We present a strong case for data-driven adaptive management that has implications for designing optimal predator management plans.

Application of UAV techniques to expand beach research possibilities: A case study of coarse clastic beach cusps

Abstract: Unmanned aerial vehicles (UAVs) have widely been documented as accessible, low cost, high-resolution coastal monitoring platforms. To date, however, UAVs have primarily been employed in coastal research as an alternative to traditional survey methods, such as beach profiling, despite their capabilities far exceeding such uses. In this contribution, we present UAV surveys as a technique to expand upon previous research possibilities through a case study on coarse clastic beach cusps. Currently no consensus exists regarding the primary mechanism responsible for development of these rhythmic features, not least due to the need for more comprehensive and timely observational data. Previous research on beach cusps is limited to repeat monitoring of a small number of cusps, or monitoring large cusp sets at relatively coarse spatial resolution. Here, repeat UAV surveys along a 600 m stretch of composite beach in New Zealand are employed to produce the most comprehensive characterisation of cusp parameters (spacing, amplitude, depth) available to date. Furthermore, the use of UAVs in this mixed sediment environment has made it possible to link cuspate morphology, such as horns and bays, to surface sediment texture. This critical advance provides new opportunities for coupling textural and topographic data in future analyses and modelling approaches. We argue that the enhanced, but still nascent, opportunity to observe morphodynamics using UAV survey methods can be critical to advancing our understanding of complex coastal zone features and changes.

Estimating the Mass of Chemicals Associated with Ocean Plastic Pollution to Inform Mitigation Efforts.

Plastic pollution in the marine environment is well documented. What remains less recognized and understood are the chemicals associated with it. Plastics enter the ocean with unreacted monomers, oligomers, and additives, which can leach over time. Moreover, plastics sorb organic and inorganic chemicals from surrounding seawater, for example, polychlorinated biphenyls (PCBs) and metals. Thus, interception and cleanup of plastics reduces the amount of chemical contaminants entering or reentering the oceans and removes those already present. Here, we estimate 1) the mass of selected chemical additives entering the global oceans with common plastic debris items, and 2) the mass of sorbed chemicals (using PCBs as a case study) associated with microplastics in selected locations. We estimate the mass of additives that entered the oceans in 2015 as constituents of 7 common plastic debris items (bottles, bottle caps, expanded polystyrene (EPS) containers, cutlery, grocery bags, food wrappers, and straws or stirrers). We calculate that approximately 190 tonnes (t) of 20 chemical additives entered the oceans with these items in 2015. We also estimate the mass of PCBs associated with microplastics in 2 coastal (Hong Kong and Hawaii) and 2 open ocean (North Pacific and South Atlantic gyres) locations, as comparative case studies. We find that the mass of chemicals is related to the mass of plastics in a location, with greater mass of PCBs closer to the source (i.e., land), where there is more plastic per unit area compared to the open ocean. We estimate approximately 85 000 times more PCBs associated with plastics in an average 4.5-km stretch of beach in Hong Kong than from the same size transect in the North Pacific gyre. In conclusion, continuing efforts for plastic interception and cleanup on shorelines effectively reduces the amount of plastic-related chemicals entering and/or reentering the marine environment. Integr Environ Assess Manag 2019;15:596-606. © 2019 SETAC.

DESIGNING BEACHSIDE RESORT AT PANTAI INDAH KALANGAN, CENTRAL TAPANULI WITH VERNACULAR ARCHITECTURE APPROACHMENT

Central Tapanuli is known for many stunning tourist locations, mainly its stretch of beach so that it becomes a great potential as an area of tourism with adequate accommodation as well as resorts. Some problems in the design resort that attract the attention and interest of tourist to come, how to design space programs according to human needs in it, and how to design buildings that are responsive to local climate, cultural and social conditions. From these problems, it is intended to create resorts with a variety of recreational facilities, design inner spaces and outdoor spaces according to resorts needs and local wisdom, and can introduce local culture to foreign tourists through resort design. Therefore, the research conducted by collecting existing location information, literature studies, comparative studies, and field surveys. After doing each step above, the result obtained, namely the design of the Beachside Resort using vernacular architecture, which is applied to each form of resort building, ranging from hotel, restaurant, cottages, spa and sauna, and other supporting facilities, using the types of the Central Tapanuli household, combined with the application of “Dalihan Natolu”. By obtaining these result, it is expected to become tourism locations and become a positive response in bringing back the traditional architecture of Central Tapanuli.

Size, age, growth and site fidelity of anadromous cutthroat trout Oncorhynchus clarkii clarkii in the Salish Sea.

Pacific salmon Oncorhynchus spp. have been the focus of scientific research for over a century, but anadromous trout in this genus, in particular anadromous coastal cutthroat trout Oncorhynchus clarkii clarkii, have been neglected. Oncorhynchus clarkii clarkii occupy a diverse range of habitats including fresh water, brackish estuaries and marine water, but have a relatively small home range making them ideal for studies of behaviour and movements during ocean residency. In 2015, we sampled O. c. clarkii monthly along a small stretch of beach (47.08° N, 122.98° W) in Eld Inlet, south Puget Sound, Washington using a beach seine. We collected tissue for genetic tagging and stock identification and scales for aging from 427 O. c. clarkii, ranging in size from 118 to 478 mm fork length. Additionally, we enumerated redds in natal streams of those fish tagged to describe inter-habitat movement patterns and investigate site fidelity of juvenile and adult O. c. clarkii in the marine environment. Consistent with other anadromous salmonids, O. c. clarkii captured at our study beach exhibited rapid growth rates, particularly in spring following dispersal into the marine environment (mean ± SD = 0.61 ± 0.29 mm-d ). Genetic tag data revealed that while O. c. clarkii undergo inter-estuarine migrations, O. c. clarkii of all life stages exhibited site fidelity in the marine environment. Twenty-one percent (64/305) of sampled O. c. clarkii were recaptured at least once during the course of the study while multiple fish (n = 3) were recaptured up to five times. These results suggest that O. c. clarkii occupying south Puget Sound reside in or regularly return to a small geographic area in the nearshore environment for much of their life and therefore may be particularly vulnerable to anthropogenic disturbance (development, angling, etc.).

The Model of Tourism Management at Malalayang Beach in Manado using AHP Approach

Malalayang beach is one of the tourism and recreation place for the people of Manado and its surroundings. Although morphologically coastal tourism at Malalayang Beach classified as rocky beach, but this beach has always been a favorite for the people of Manado for recreation, especially on Sundays and holidays. The strategic location of this Malalayang beach is located near the highway and also located on the border between Manado city and Minahasa district. In its development, Malalayang beach for tourism has several problems in management. One of the problems faced is the frequent congestion caused by the lack of space for parking of visitors vehicles, In addition, inadequate facilities such as a place to rinse and toilet and the absence of a lifeguard that oversees the safety of visitors. From the various problems that arise required research for the selection of malalayang coastal tourism manado city with AHP method to know the right results. This research was conducted in Malalayang as coastal tourism area in Malalayang Dua Village, Malalayang District, Manado City. The length of this Malalayang tourist beach stretches approximately 1.25 km. using the quantitative method is elaborated using the AHP method. The study indicates that the Choice for Malalayang Coastal Tourism Manager is an alternative to the community with the highest priority value of 0,509. With a 0.08 inconsistency value that is below 0.1 then the results of this study may be accepted. Choice of Community as Malalayang Coast Tour manager get high priority value on Safety and Comfort criteria as well as criteria of Coastal Environment Quality. For tourist attraction criteria the highest value is private and for the criteria of facilities and infrastructure the highest value is the government. Suggestions that need to be considered is the need for collaboration both from the government and the private sector to manage the Malalayang Beach as tourist attraction. It also needs further research to find out the collaborative management model of Malalayang beach to be applied into tourism attraction management practices.

Small-scale changes of an arthropod beach community after hard-engineering interventions on a Mediterranean beach

Sandy beaches and their resident communities are subjected to increasing impacts of human interventions and activities. Still, very little is known about the effects of hard engineering interventions on sandy beach ecosystems. This study analysed the arthropod community on a beach stretch of about ten kilometres in the western Mediterranean coast of Italy. This is a microtidal and exposed sandy beach at the delta of Ombrone River, long since subjected to coastal erosion. Aiming at contrasting erosion dynamics, a seawall of about one thousand metres was constructed landwards at one side of the river mouth, and several perpendicular groynes were made in the sublittoral zone in front of the wall and one thousand metres further. The objectives of this study were to (1) identify the main drivers defining the arthropod community structure on a changing Mediterranean sandy beach and (2) evaluate whether the anti-erosion hard-engineering interventions had any effects on the arthropod community along the beach continuum, at the two sides of the river mouth. Arthropods were sampled on the beach every three months, over a two year period, during and after the hard-engineering works. Individuals were counted and identified when possible to the species level; data were analysed with multivariate factor analysis, which was used as an exploratory tool to reveal relationships among variables. The results proved a correlation of the community composition with coastal erosive–accretive dynamics, climatic (seasonal) changes and beach width. Biotic interactions seem to have assumed a major role in defining the community composition in the beach stretch where the seawall has already affected the coastal dynamics by producing beach accretion.

Dynamic equilibrium of sandbar position and height along a low wave energy micro-tidal coast

Nearshore sandbars play an essential role in dissipating incident wave energy and protecting the beach landward. Thus, understanding the dynamic equilibrium of nearshore bars is valuable to beach management and shore protection. This study examines the sandbar equilibrium in terms of bar height and cross-shore bar location, in order to assess how the dynamic equilibrium is maintained and influenced by storms along a low wave energy micro-tidal coast. The bar height and bar position were extracted from 51 beach profiles surveyed every two months, spaced at 300 m along a 15-km stretch of beach from October 2010 to August 2014. For the studied coast, alongshore variation in equilibrium bar position measured from the shoreline ranges between 40 and 80 m and equilibrium bar height between 0.20 and 0.70 m. Greater equilibrium sandbar height tends to occur around a headland, where waves are higher. Alongshore variations of bar behavior were observed during storms, with both onshore and offshore bar migration observed during one storm. Water depth over the pre-storm sandbar crest is a major factor controlling the storm-induced onshore or offshore bar migration. On average, the depth over the onshore migrating sandbar is found to be 0.20 m deeper than that over the offshore migrating bar during both summer and winter storms. There is no significant correlation between incident wave angle and sandbar height changes, while significant correlation exists between wave angle and sandbar movement under certain wave conditions, with more oblique waves being associated with further offshore movement of the sandbar. Energetic storm conditions tend to make the bar higher than the equilibrium height, while post-storm adjustment would restore the equilibrium height within 4–6 months. Although the exact values may vary at different locations, the concept of dynamic equilibrium of bar height and distance to shoreline could apply at many locations.

Coastal protection by a small scale river plume against oil spills in the Northern Gulf of Mexico

The Deepwater Horizon oil spill damaged some beaches along the Northern Gulf of Mexico (NGoMex) coast more than others, possibly related to the presence of natural protection mechanisms. In order to optimize future mitigation efforts to protect the coast, these mechanisms should be understood. The NGoMex coast is characterized by relatively long stretches of sandy beach interrupted by tidal inlets creating ebb-tidal river plumes featuring frontal zones that may act as transport barriers. This research investigates to what extent these plumes are capable of protecting the adjacent coast. This is done by means of a combination of a 3D Eulerian flow model and a Lagrangian particle model to track oil pathways and visualize Lagrangian Coherent Structures located at the plume front. The models are verified with measurements from a field experiment adjacent to Destin Inlet, Florida. The effects of wind, tidal range and river discharge on the oil fate are discussed. It was found that wind is the dominant parameter. Offshore wind prevents oil from beaching. During onshore winds, oil is pushed to shore, but near the inlet the plume is effective in reducing the amount of oil washing ashore during the ebbing tide. In general, the plume redistributes the oil but is not capable of preventing oil from beaching. For strong winds, the influence of the plume is reduced.

Short-time analysis of shoreline based on RapidEye satellite images in the terminal area of Pecém Port, Ceará, Brazil

ABSTRACTCoastal environments are highly dynamic and sensitive to interference and variations caused by the numerous natural and anthropogenic agents. The northern coast of Northeastern Brazil has undergone intense erosion in recent years. However, the construction of the Pecém Port modified the beach and shoreline features differently from the adjacent areas. This article describes using remote-sensing images integrated with a Geographic Information System to evaluate the sedimentary balance and morphological changes observed in the sandy beach area that was affected by the construction of Pecém Port. Two methods were applied to the RapidEye images to quantify the short-time changes that occurred on the coast. The Digital Shoreline Analysis System method showed that the beach width increased west to the port, which was calculated by the Change Polygon Approach determined by intersecting and uniting polygons to estimate the difference between the areas over time. The short-time analysis results showed changing coastal morphology, demonstrating that the anthropic interventions in the region are transforming significantly the natural elements that make up the region landscape. Between 2011 and 2014, the investigated beach stretch of approximately 3 km suffered an accretion process of more than 102,000 m2 over 3 years. The high spatial resolution of satellite images, digital processing imaging techniques and geostatistical methods were effective in this study, allowing understanding the recent changes in the area.