Analysis of coastal sediment transport processes from Wrightsville Beach to Fort Fisher, North Carolina /

A comprehensive engineering analysis of the coastal sediment transport processes along a 42-kilometer segment of the North Carolina shoreline from Wrightsville Beach to Fort Fisher is presented. Included in the analysis is an interpretation of the littoral processes, longshore transport, and the behavior and success of beach nourishment projects at Wrightsville Beach and Carolina Beach, North Carolina. The historical position of the MLW, MSL, and MHW contours, relative to a fixed base line, is plotted for the period between 1964 and 1975. An equivalent volumetric erosion or accretion between successive surveys is determined by multiplying the average excursion distance of the contours by a constant of proportionality. The plots of excursion distance versus time for the MLW, MSL, and MHW contours also show the time response of the beach fills. This response is described by a mathematical function. The alongshore components of wave-induced energy flux are also determined within the study area through wave refraction analysis. This information, together with the information on volumetric change, is used in a sediment budget analysis to determine the coefficient of alongshore sediment transport and the inlet trapping characteristics. (Author).

Mineralcomposition of beach sediments from the area "Fähre Großenbrode-Kliff Wulfen" on Fehmarn

Um die Insel Fehmarn und an der Nordküste Wagriens wurden rund 2500 Strand-, Flachwasser- und Seesandproben zum Erkennen der Materialtransportwege sedimentpetrographisch untersucht. Für die Schwermineralbestimmung wurde hauptsächlich die Fraktion 0,2-0,1 mm herangezogen, da diese für die vorliegenden Sedimente charakteristisch ist. Da die Mineralzusammensetzung der Sedimente im gesamten Untersuchungsgebiet gleich ist, also nirgends örtlich sog. Leitminerale zugeführt werden, wurden bei der Auswertung der Analysenergebnisse die hydrographischen Verhältnisse der westlichen Ostsee und die Abhängigkeit des Sedimentes von der Kraft des bewegten Meerwassers beachtet. Bezüglich der Abhängigkeit des transportierten Materials von der Wasserkraft werden drei voneinander abweichende Systeme, nämlich der Strand, die Brandungszone und das tiefere Wassergebiet, erkannt. Am Strand ist die angewandte Untersuchungsmethode sowohl an langgestreckten Küsten als auch in stark untergliederten Ufergebieten zum Erkennen der Sandwanderbahnen geeignet. Erosion und Neuzuführung von Material auf dem Transportwege zeigen das gleiche mineralische Bild, und eine Entscheidung, welcher dieser beiden Fälle tatsächlich vorliegt, kann nur im Gelände getroffen werden. Die Korngrößenanalyse allein ist zur Beantwortung vorliegender Fragestellungen nicht brauchbar, weil durch gegebene hydrographische Bedingungen die Korngröße in Transportrichtung sowohl abnehmen als auch zunehmen kann. In Strandgebieten mit veränderter natürlicher Beschaffenheit der Sedimente und an Küsten mit ausgedehnten vorgelagerten materialliefernden Abrasionsflächen ist die Grenze der Methode aufgezeigt. Höfte, Haken und Sandinseln zeigen jeweils typische mineralische Zusammensetzungen ihres Strandes, aus welchen die Entstehung der betreffenden Anlandungsformen abgeleitet werden kann. Quer über die Brandungszone weisen die Sedimente auf engem Raum wechselnde Mineralzusammensetzung auf, aus der auf die örtlichen hydrographischen Verhältnisse geschlossen werden kann. Zum Vergleich sedimentpetrographischer Ergebniswerte sind nur Sande, die unter gleichen Ablagerungsbedingungen entstanden sind, geeignet. Zum Erkennen der Materialwanderwege wurden entweder Sandproben von den Riffkämmen oder aus den Rinnen zwischen zwei Sandanhäufungszonen untersucht. In beiden Fällen wurden die Transportrichtungen erkannt. In Gebieten, in denen die Strandsanduntersuchungen negativ verliefen, ließen die Riffsandproben Schlüsse auf die Materialschüttungsrichtungen zu. An exponierten Küsten mit mehreren wirksamen Windrichtungen darf jedoch nicht von dem einen auf das andere Wandersystem geschlossen werden. Eine Umkehr der Materialvertriftung zwischen Flachwasser und Strand kann vorliegen. Im tieferen Wasser ist es möglich, mit gleicher Methode unter Berücksichtigung der Morphologie des Meeresgrundes die Materialschüttungsrichtung zu erkennen. Zur Sedimentuntersuchung auf Linienprofilen sind nur Proben gleicher Wassertiefe geeignet; die Sonderung des Materials nach der Tiefe muß beachtet werden. Aus den ermittelten sedimentpetrographischen Werten lassen sich eine Reihe von Beziehungen ablesen, die zur Deutung der Mineralgesellschaft und für die Auswertung der Untersuchungsergebnisse herangezogen werden können. Als regionales Ergebnis der vorstehenden Untersuchung kann eine Karte der Küsten Fehmarns und Nordoldenburgs vorgelegt werden, in der die Sandwanderungswege am Strand, in der Flachwasserzone und in den daran anschließenden tieferen Wassergebieten dargestellt sind.

Texture and composition of the Rosa Marina beach sands (Adriatic coast, southern Italy): a sedimentological/ecological approach

Beach sands from the Rosa Marina locality (Adriatic coast, southern Italy) were analysed mainly microscopically in order to trace the source areas of their lithoclastic and bioclastic components. The main cropping out sedimentary units were also studied with the objective to identify the potential source areas of lithoclasts. This allowed to establish how the various rock units contribute to the formation of beach sands. The analysis of the bioclastic components allows to estimate the actual role of organisms regarding the supply of this material to the beach. Identification of taxa that are present in the beach sands as shell fragments or other remains was carried out at the genus or family level. Ecologi- cal investigation of the same beach and the recognition of sub-environments (mainly distinguished on the basis of the nature of the substrate and of the water depth) was the key topic that allowed to establish the actual source areas of bioclasts in the Rosa Marina beach sands. The sedimentological analysis (including a physical study of the beach and the calculation of some statistical parameters concerning the grain-size curves) shows that the Rosa Marina beach is nowadays subject to erosion.

Effect of sea water level rise on sandy beach profile

Study of batch profile evolution and scouring effect due to the wave and current impacts in the coastal zone has been one of the most important issues in coastal engineering research projects during the past decades .to construct the coastal protective structures such piers, breakwaters and seawalls, it is necessary to estimate the scouring depth and bed level changes in the vicinity of such structures. Furthermore, the time - dependent changes in the equilibrium profile of the surf zone can be of great importance in designing coastal structures. Because of the importance of coastal engineering study in Iran due to the existence of two important coastal area located in the north and south parts of the country, and due to the lack of classified data in this respect (particularly the effect of sea level rise on coastal morphology) in the present study, based on the available data of Bandar Anzali region, an analysis of the coastal zone behavior is made. Bed level elevations are measured and compared with the theoretical equilibrium profile. It is shown that the behavior of the coastal zone in the region is consistent with the dean (equilibrium profile . In the next stage, following extensive investigations, the bed level changes due to a rise in sea level at different locations in the surf zone are estimated. Finally based on the results obtained for profile evolution due to sea level rise, the conclusion is made for design of coastal structures located in the study area. The results obtained from the present study indicate that the sea level rise can have a significant effect on beach profile and resulting erosion in the study area. The results are graphically presented with can be used for design purposes and establishing a data base for the coastal zone in the study region. It is believed that the present work can be regarded as a contribution to the existing knowledge of coast process in the study area and referred to as a basis for the future coastal research projects.

Monitoring and modelling the morphodynamic evolution of a breached barrier beach system

Predicting the evolution of a coastal cell requires the identification of the key drivers of morphology. Soft coastlines are naturally dynamic but severe storm events and even human intervention can accelerate any changes that are occurring. However, when erosive events such as barrier breaching occur with no obvious contributory factors, a deeper understanding of the underlying coastal processes is required. Ideally conclusions on morphological drivers should be drawn from field data collection and remote sensing over a long period of time. Unfortunately, when the Rossbeigh barrier beach in Dingle Bay, County Kerry, began to erode rapidly in the early 2000’s, eventually leading to it breaching in 2008, no such baseline data existed. This thesis presents a study of the morphodynamic evolution of the Inner Dingle Bay coastal system. The study combines existing coastal zone analysis approaches with experimental field data collection techniques and a novel approach to long term morphodynamic modelling to predict the evolution of the barrier beach inlet system. A conceptual model describing the long term evolution of Inner Dingle Bay in 5 stages post breaching was developed. The dominant coastal processes driving the evolution of the coastal system were identified and quantified. A new methodology of long term process based numerical modelling approach to coastal evolution was developed. This method was used to predict over 20 years of coastal evolution in Inner Dingle Bay. On a broader context this thesis utilised several experimental coastal zone data collection and analysis methods such as ocean radar and grain size trend analysis. These were applied during the study and their suitability to a dynamic coastal system was assessed.

Provenance of Holocene beach sand in the Western Iberian

Detrital zircons from Holocene beach sand and igneous zircons from the Cretaceous syenite forming Cape Sines (Western Iberian margin) were dated using laser ablation – inductively coupled plasma – mass spectrometry. The U–Pb ages obtained were used for comparison with previous radiometric data from Carboniferous greywacke, Pliocene–Pleistocene sand and Cretaceous syenite forming the sea cliff at Cape Sines and the contiguous coast. New U–Pb dating of igneous morphologically simple and complex zircons from the syenite of the Sines pluton suggests that the history of zircon crystallization was more extensive (ca 87 to 74 Ma), in contrast to the findings of previous geochronology studies (ca 76 to 74 Ma). The U–Pb ages obtained in Holocene sand revealed a wide interval, ranging from the Cretaceous to the Archean, with predominance of Cretaceous (37%), Palaeozoic (35%) and Neoproterozoic (19%) detrital-zircon ages. The paucity of round to subrounded grains seems to indicate a short transportation history for most of the Cretaceous zircons (ca 95 to 73 Ma) which are more abundant in the beach sand that was sampled south of Cape Sines. Comparative analysis using the Kolmogorov–Smirnov statistical method, analysing sub-populations separately, suggests that the zircon populations of the Carboniferous and Cretaceous rocks forming the sea cliff were reproduced faithfully in Quaternary sand, indicating sediment recycling. The similarity of the pre- Cretaceous ages (>ca 280 Ma) of detrital zircons found in Holocene sand, as compared with Carboniferous greywacke and Pliocene–Pleistocene sand, provides support for the hypothesis that detritus was reworked into the beach from older sedimentary rocks exposed along the sea cliff. The largest percentage of Cretaceous zircons (erosion during Quaternary uplift. This work highlights the application of the Kolmogorov–Smirnov method in compar- ison of zircon age populations used to identify provenance and sediment recycling in modern and ancient detrital sedimentary sequences.

Abundância de ramos reprodutivos e produção de sementes em populações de Ipomoea pes-caprae (L.) R. Br. na Ilha de Santa Catarina, Brasil

The variation in the proportion of reproductive branches, fruit, and seed production of Ipomoea pes-caprae (L.) R. Br. (Convolvulaceae) were evaluated at ten beaches on Santa Catarina Island, state of Santa Catarina, Brazil. Three patches per beach of Ipomoea pes-caprae were monitored, involving two reproductive cycles. Ipomoea pes-caprae presented initially an average length of patches of 14 m, with 9.6 branches/m² and 39% of reproductive branches. The proportion of reproductive branches varied between the cycles, but there was not noticed an alternation of reproductive effort between the subsequent cycles. There was a reduction in the percentage of reproductive branches at six localities. In four beaches where Ipomoea pes-caprae populations declined, occurred reduction in the reproductive vigor, and in the seed production, being these declines associated to strong sea erosion. In another hand, in one beach with population increase, there were little reproductive branches due to the occurrence of young stolons. Four patches never maturated fruits, being three of these located at small beaches. The fruit and seed productions in the patches showed values up to 40 fruits/m² and up to 140 seeds/m², respectively. Populations with great seed production were localized in areas adjacent to great coastal plains, which may represent potential seed sources for areas with small seed production in the island.

Insights into preventive measures for dental erosion

Dental erosion is defined as the loss of tooth substance by acid exposure not involving bacteria. The etiology of erosion is related to different behavioral, biological and chemical factors. Based on an overview of the current literature, this paper presents a summary of the preventive strategies relevant for patients suffering from dental erosion. Behavioral factors, such as special drinking habits, unhealthy lifestyle factors or occupational acid exposure, might modify the extent of dental erosion. Thus, preventive strategies have to include measures to reduce the frequency and duration of acid exposure as well as adequate oral hygiene measures, as it is known that eroded surfaces are more susceptible to abrasion. Biological factors, such as saliva or acquired pellicle, act protectively against erosive demineralization. Therefore, the production of saliva should be enhanced, especially in patients with hyposalivation or xerostomia. With regard to chemical factors, the modification of acidic solutions with ions, especially calcium, was shown to reduce the demineralization, but the efficacy depends on the other chemical factors, such as the type of acid. To enhance the remineralization of eroded surfaces and to prevent further progression of dental wear, high-concentrated fluoride applications are recommended. Currently, little information is available about the efficacy of other preventive strategies, such as calcium and laser application, as well as the use of matrix metalloproteinase inhibitors. Further studies considering these factors are required. In conclusion, preventive strategies for patients suffering from erosion are mainly obtained from in vitro and in situ studies and include dietary counseling, stimulation of salivary flow, optimization of fluoride regimens, modification of erosive beverages and adequate oral hygiene measures.

Scanning electron microscopic study of the in situ effect of salivary stimulation on erosion and abrasion in human and bovine enamel

This in situ study investigated, using scanning electron microscopy, the effect of stimulated saliva on the enamel surface of bovine and human substrates submitted to erosion followed by brushing abrasion immediately or after one hour. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 minutes in 150 ml of a cola drink, 4 times a day (8h00, 12h00, 16h00 and 20h00). Immediately after the immersions, no treatment was performed in 4 specimens (ERO), 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice and the device was replaced into the mouth. After 60 min, the other 4 specimens were brushed. In the second phase, the procedures were repeated but, after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Enamel superficial alterations of all specimens were then evaluated using a scanning electron microscope. Enamel prism core dissolution was seen on the surfaces submitted to erosion, while on those submitted to erosion and to abrasion (both at 0 and 60 min) a more homogeneous enamel surface was observed, probably due to the removal of the altered superficial prism layer. For all the other variables - enamel substrate and salivary stimulation -, the microscopic pattern of the enamel specimens was similar.

The influence of residual salivary fluoride from dentifrice on enamel erosion: an in situ study

The objective of this study was to assess the salivary residual effect of fluoride dentifrice on human enamel subjected to an erosive challenge. This crossover in situ study was performed in two phases (A and B), involving ten volunteers. In each phase, they wore acrylic palatal appliances, each containing 3 human enamel blocks, during 7 days. The blocks were subjected to erosion by immersion of the appliances in a cola drink for 5 minutes, 4 times a day. Dentifrice was used to brush the volunteers’ teeth, 4 times a day, during 1 minute, before the appliance was replaced into the mouth. In phases A and B the dentifrices used had the same formulation, except for the absence (PD) or presence (FD) of fluoride, respectively. Enamel alterations were determined using profilometry, microhardness (%SMHC), acid- and alkali-soluble F analysis. The data were tested using ANOVA (p < 0.05). The concentrations (mean ± SD) of alkali- and acid-soluble F (µgF/cm²) were, respectively, PD: 1.27ª ± 0.70/2.24A ± 0.36 and FD: 1.49ª ± 0.44/2.24A ± 0.67 (p > 0.05). The mean wear values (± SD, µm) were PD: 3.63ª ± 1.54 and FD: 3.54ª ± 0.90 (p > 0.05). The mean %SMHC values (± SD) were PD: 89.63ª ± 4.73 and FD: 87.28ª ± 4.01 (p > 0.05). Thus, we concluded that the residual fluoride from the fluoride-containing dentifrice did not protect enamel against erosion.

Surface and subsurface erosion of primary enamel by acid beverages over time

This study evaluated the influence of a cola-type soft drink and a soy-based orange juice on the surface and subsurface erosion of primary enamel, as a function of the exposure time. Seventy-five primary incisors were divided for microhardness test (n=45) or scanning electron microscopy (SEM) analysis (n=30). The specimens were randomly assigned to 3 groups: 1 - artificial saliva (control); 2 - cola-type soft drink; and 3 - soy-based orange juice. Immersion cycles in the beverages were undertaken under agitation for 5 min, 3 times a day, during 60 days. Surface microhardness was measured at 7, 15, 30, 45 and 60 days. After 60 days, specimens were bisected and subsurface microhardness was measured at 30, 60, 90, 120, 150 and 200 µm from the surface exposed. Data were analyzed by ANOVA and Tukey’s test (a=0.05). Groups 2 and 3 presented similar decrease of surface microhardness. Regarding subsurface microhardness, group 2 presented the lowest values. SEM images revealed that after 60 days the surfaces clearly exhibited structural loss, unlike those immersed in artificial saliva. It may be concluded that erosion of the surfaces exposed to the cola-type soft drink was more accentuated and directly proportional to the exposure time.

Viability of using enamel and dentin from bovine origin as a substitute for human counterparts in an intraoral erosion model

This study ascertained whether under dental erosion models that closely mimics the real-life situation enamel and root dentin from bovine origin would be reliable substitutes for human counterparts. Through a 2x2 crossover design, in a first trial, 14 volunteers wore a palatal device containing slabs of bovine and human enamel. Half of the participants ingested (4x daily, for 10 days) orange juice first, crossing over to mineral water, while the remainder received the reverse sequence. In a second trial, volunteers wore devices with slabs of bovine and human root dentin. Except for the duration of each intraoral phase, which lasted 2 rather 10 days, the experiment with root dentin run exactly as for enamel. Dental substrates were analyzed for surface microhardness. Two-way ANOVAs (α=0.05) indicated no difference between the microhardness values recorded for human and bovine enamel (p=0.1350), but bovine root dentin had lower microhardness compared to its human counterpart (p=0.0432). While bovine enamel can reliably substitute its human counterpart in in situ dental erosion models, bovine root dentin does not seem to be a viable alternative to the corresponding human tissue.

Effects of temperature and salinity on the survival rates of coxicerberus ramosae (Albuquerque, 1978), an interstitial isopod of a Sandy Beach on the coast of Brazil

The tolerance to the combined effects of temperature and salinity was investigated in the interstitial isopod Coxicerberus ramosae (Albuquerque, 1978), a species of intertidal zone of sandy beaches in Rio de Janeiro, Brazil. The animals were collected on Praia Vermelha Beach. The experiments lasted 24 h and nine salinities and seven temperatures were used for a total of 63 combinations. Thirty animals were tested in each combination. The species showed high survival in most of the combinations. The temperature of 35 ºC was lethal and at 5 ºC, the animals tolerated only a narrow range of salinities. The statistical analyses showed that the effects of temperature and salinity were significant on the survival, which confirmed the euryhalinity and eurythermy of this species.