Modern and abandoned Pleistocene rocky shores are described for several of the Seychelles Islands in order to examine the range of erosional features typical of granite shores in a tropical setting and to gauge the prospects for their preservation at unconformities in the rock record. The proportion of sandy beaches to rocky shores is estimated for each of the various islands under consideration, including Mahé, Praslin, Ronde, La Digue, Grande Sœur, and Cocos. Aspects of physical geography related to the position of reefs and the variable width of lagoons that surround and buffer the islands is considered with respect to the regional pattern of prevailing winds and oceanic circulation. Literature on the erosion of granite landforms is reviewed and applied to the Seychelles Inner Islands and the Seychelles Bank on which they sit. Outcrops of Pleistocene limestone closely associated with granite surfaces were searched for body fossils that represent an intertidal rocky-shore biota. Coralline red algae and vermetid gastropods are the primary components of laminated limestone attached directly to granite surfaces as protective bioconstructions. Cemented limestone rubble includes the body fossils of a dozen different kinds of invertebrates also found extant on modern granite shores in the Seychelles. Among them are gastropods that represent a range of different life styles, as well as corals.

This article examines the seasonal variability of nontidal contributions of the sea level oscillations off Tikkavanipalem coast in Andhra Pradesh (India), which is located on the western boundary of the Bay of Bengal. The analysis is based on simultaneous observations of tidal and surface meteorological parameters in four temporal segments of 1-month duration each during a 1-year period in 1997–98. Sea level oscillations along the Tikkavanipalem segment of the central east coast of India contain contributions from tidal and set-up/set-down motions. Local wind pattern, coastal current, and air pressure variations particularly influence the residual sea level elevation (difference of the measured and astronomically induced daily mean sea level) in this region. Observed response of the sea level elevation to the barometric pressure represents an amplified/delayed inverted barometer effect. The relative importance of tidal and nontidal contributions to the sea level is found to be seasonal, as the coastal current and the meteorological forcing suffer large seasonal variations.

Measurements of cross-shore velocity (u) at z = 3 cm and suspended sediment concentration (SSC) at z = 1–33 cm were collected from the swash zones of gently sloping (Perranporth, UK) and steep (Sennen, UK) beaches, during morphodynamic conditions ranging from highly dissipative to almost reflective and breaker heights ranging from 0.8 to 2.2 m. Nine swash-zone data collection runs were used to compare the performance of simplified versions of Bagnold-type energetics sediment transport models on the two different beaches. Models originally designed for suspended load, where the sediment transport (I) is approximately proportional to u⁴, showed no apparent improvement over those intended for bedload, where I ∝ u³. It is suggested that the lowest SSC sensors could be measuring high concentrations in the sheet-flow layer, where previous laboratory results suggest a u³ model is most appropriate. The overall performance of the model is better (average r² = 76%) on the gently sloping beach than on the steep beach (average r² = 49%). Modifications to account for processes, such as bore turbulence, may improve the model's performance, particularly on steep reflective beaches.

The three-dimensional circulation, salinity distribution, and overall transport pattern were simulated in the Pearl River Estuary, China, using a modified version of the Princeton Ocean Model (POM). The circulation in the estuary is mainly driven by tide, wind, and river runoff in a complex manner, where the relative importance of the different forcing factors varies over the year. Field data on currents from several locations in the estuary taken at different elevations through the water column were employed to validate the model together with measurements of the salinity distribution in the surface layer. Also, satellite images were utilized to qualitatively confirm the simulated overall transport pattern. Comparisons between measurements and calculations showed that the POM yielded satisfactory predictions without any particular calibration. However, for some events the coastal current outside the estuary induced by the large-scale circulation in the South China Sea affected the flow in the estuary, making it necessary to employ a more sophisticated boundary condition on the ocean side than what was initially implemented. The long-term objective of the numerical modeling of the flow and material transport in the Pearl River Estuary is to utilize the validated model for forecasting the circulation and water quality in the estuary in a comprehensive system where in-situ measurements and remote sensing are the other main components.

A port complex was implanted in the coast region of Suape, PE-Brasil, in 1979–80, which altered the geomorphological and hydrodynamic conditions of the area, mainly in the estuary of the Ipojuca River. Water samples were collected from the surface and the deep layer to determine the salinity, pH, dissolved oxygen, transparency, and temperature from three fixed stations in the estuary of the Ipojuca River during the summer and winter before (1978) and after (1986–87) the port's construction, in order to evaluate the effects of the port-induced changes. The data were subjected to a principal component analysis and to individual t tests. The first principal component, the axis of maximum information, alone explained 50% of the total variance, being associated with the generalized increase of the chemical parameters after the port's construction, mainly the salinity. Despite the fact that the results of the t tests presented significant differences only for the dissolved oxygen, pH, and temperature, the increased salinity produced the greatest ecological effects in the estuary. The water flow of the Ipojuca River was diverted toward the ocean, decreasing the river-flow velocity at the mouth. This decrease in flow caused a sedimentation in the area, a decrease in the circulation and depth, and a transformation of the mouth of the river into a coastal lagoon with an increase in evaporation and salinity. A delay of more than 2 hours was observed in the dynamic tide in relation to the normal 6-hour cycles. Despite an increase in the concentration of dissolved oxygen and transparency values, effects that theoretically improve environmental conditions, a morphological transformation occurred that caused drastic changes in the estuary's circulation and in the tidal currents.

Measurements of longshore sediment transport rate were conducted on a reflective to intermediate sandy beach during energetic sea breeze activity. The suspended load transport was obtained with optical backscatter sensors, current meters, and streamer traps, whereas the total load rate was measured with fluorescent sand tracer. The streamer trap measurements revealed an exponential vertical distribution of the suspended sediment flux, with the degree of vertical mixing decreasing in the onshore direction. A continuous time series of longshore suspended sediment flux across the surf zone was obtained by combining streamer trap measurements with data collected with surf zone instruments. Comparison of the suspended longshore flux with the total longshore flux derived from the dispersal of fluorescent tracer indicated that the relative contribution of suspended load to total load was ca. 35%. The movement of sand tracer further demonstrated that nearshore sediments were transported obliquely across the surf zone, challenging our conventional view of dividing nearshore sediment transport into cross-shore and longshore components. Sand tracer was found to move onshore as well as offshore, indicating a bi-directional sediment exchange between outer surf zone and swash zone. Equations from previous studies predicted the suspended longshore transport rate rather well, but underestimated the total longshore transport rate by a factor of two. The Kamphuis formula underestimated both suspended and total longshore transport rates.

This article examines the vulnerability of US coastal counties to erosion by combining a socioeconomic vulnerability index with the US Geological Survey's physically based coastal vulnerability index. The end product is a county-based index of overall coastal place vulnerability. The results indicate that place vulnerability along the coast is highly differentiated and influenced by a range of social, economic, and physical indicators. Regionally, Gulf Coast vulnerability is more of a product of social characteristics rather than physical attributes. The opposite is true of Pacific and Atlantic coastal counties, where physical characteristics are more influential in determining erosion-hazard vulnerability. It is clear that overall vulnerability of coastal counties cannot be determined without the union of social, economic, built-environment, and physical characteristics. Yet the methods for combining these components are not widely used at present by coastal scientists and policy makers, rendering hazards assessments incomplete and mitigation plans untenable for many places.

Lithostratigraphy of the Holocene Lake Illawarra barrier estuary on the New South Wales coast, Australia, adds details to previous models of barrier estuary evolution. Establishment of a detailed chronology, with the use of 121 aspartic acid–derived ages and six radiocarbon ages, has allowed the definition of a five-stage geomorphic model for the infill of the barrier estuary. A broad incised valley formed during the sea level lowstand represents the initial stage. Stage two is represented by a basal transgressive marine sand sheet deposited in response to rising sea levels associated with the last postglacial marine transgression, which inundated the shallow incised valley ca. 8000–7500 years ago. This feature is not present in the deeper and narrower incised valleys used to establish previous barrier estuary models. The more open marine conditions, with a diverse assemblage of estuarine and marine mollusc species, persisted until ca. 5000 years ago when the barrier started to become emergent and resulted in the development of a low-energy back-barrier lagoonal environment (stage 3). A late Holocene regression (1–2 m) of sea level between 3200–2500 years ago (stage 4) further restricted oceanic circulation and increased the rate of fluvial bay-head delta progradation. The final stage has seen a rapid extension of the fluvial deltas and increased rates of lagoonal sedimentation during the past 200 years as a result of land clearing for agriculture and urban and industrial development. This five-stage evolutionary model of barrier estuary evolution developed for Lake Illawarra can be applied to other shallow estuaries on tectonically stable, wave-dominated coastlines.

The current system in the Strait of Singapore is fairly complicated and variable because it is under the influence of major currents driven by trade winds as well as the Asian monsoons. In addition to tidal forcing, circulation in the Strait is governed by a strong hydrodynamic pressure gradient which reverses direction semi-annually and coincides with seasonal monsoon changes. In this investigation, we examine the mechanism that controls the circulation in the Strait of Singapore by using a three-dimensional circulation model forced by hydrodynamic pressure gradient, tides and winds. Model results delineate in detail the characteristics of circulation and hydrodynamic structure in the strait. These results compare favourably with the available field measurements and agree, in general, with observations. It is shown that: (1) the low frequency net transport across the strait correlates well with the seasonal hydrodynamic pressure gradient, and (2) the tidal variation across the strait have a significant effect on the circulation in the Strait.

Marine water quality is one of the priorities among contemporary Black Sea environmental issues. Its major importance and complex implications are evinced by international and national concerted concern and actions, such as the control of eutrophication and the financing of nutrient reduction supported by the Global Environment Facility (GEF), the continued European Union (EU) commitment to the Black Sea, the Strategic Action Plan for the Rehabilitation and Protection of the Black Sea with related National Action Plans for the entire region.

Coastal water quality along the Romanian Black Sea coast will be considerably improved by the full operation of four wastewater treatment plants at Constantza Nord, Constantza Sud, Eforie Sud and Mangalia until the end of 2008: following main achievements are expected from the modernization of mentioned facilities:

A total of 54 sites were sampled with pitfall traps in order to investigate the distribution of epigeal (soil-surface) beetle (Coleoptera) assemblages along the coast of north-east England. Classifications of ground, rove and phytophagous beetles showed that the species assemblages on saltmarsh sites differed considerably from those on dunes and slacks and had far fewer species. The variables affecting the distribution of assemblages were soil water and vegetation cover for ground and phytophagous beetles but only vegetation cover for rove beetles. It is likely that sea level rise on the east coast of England would change species-rich dune slack and low-lying farmland habitats into species-poor saltmarsh-type habitats, with a considerable change in species assemblage composition. This has implications for coastal site restoration.

To assess the possibility of restoring the original plant community of grey dune from a pine plantation, a synchronic study of the seed banks of three habitats, the grey dune, the pine plantation, and a clearing, was conducted at Quiberon (France). Five stations were selected: a Grey dune, Pine plantation 1, Pine plantation 2, Clearing 1, and Clearing 2. In contrast to the pine plantations, clearing 1, subject to heavy human disturbance, had a great similarity between its seed banks and its established vegetation. The larger clearing (C2) tend to resemble the grey dune, whereas the other was dominated by ruderal species.

The analysis of the seed banks demonstrated differences between the clearings and the pine plantations from which they were derived. The potential vegetation of the clearings was closer to that of the grey dune and had a larger number of species with a short life cycle than the pine plantations.

The seed banks of the pine plantations were not similar to that of the grey dune, but also differed from that of closed vegetation. This study suggested that it may not be possible to obtain a short term restoration of a grey dune after just clear felling only with the help of seed banks. On the other hand, seed dissemination could facilitate a restoration in a larger time scale as for clearings.

Optically stimulated luminescence ages were done on beach ridge samples from the Cape Peninsula, Merritt Island, and a mainland location in Brevard County, Florida. Age estimates on the peninsula ranged from 4000 to 150 years ago; while on Merritt Island, a beach-ridge sample yielded an age of about 43,000 years ago. The mainland sample, near Titusville, gave an age of about 8000 years. Using the age estimates for four ridges on the Canaveral Peninsula, average land accretion rates and beach-ridge accumulation rates were determined by measuring distances perpendicular to strike of the ridge sequences and counting ridges along these trends. The average ridge spacing was found to be 109 ± 20 m, the average ridge accumulation rate was 80 ± 8 y/ridge, and the average land accretion rate was found to be 135 ± 12 m per hundred years. We suggest that the ridge accumulation rate can be used to determine storm recurrence intervals on the peninsula. The peninsular age estimates show the problems associated with radio-carbon dating of shell, which overestimate burial ages by several thousand years due to reworking of older shell into younger deposits.

Algal blooms, often associated with eutrophication, are common in temperate regions in coastal lagoons and estuarine areas as well as in open seas. However, because of recent changes in water flows and sediment and nutrient loads in most rivers, eutrophication phenomena are now occurring in areas previously non affected. One of its most widespread and easily recognized effects in a coastal marine ecosystem is the excessive growths and drifts of macroalgae, to such a degree that the biomass becomes a significant problem.

The nutrients, notably from anthropogenic origin, constitute a significant factor in the appearance of the blooms in coastal waters. Besides a background originating from natural areas and precipitations, nutrients come from agriculture, sewage, industry, and aquaculture, in very various proportions following the local conditions.

At first, the development of opportunist and tolerant seaweeds acts as a purifying system. Then, when the seaweed is stranded or the environmental conditions become unfavourable, the plants die and decompose. The degradation of the chemical equilibrium induces the break-down of the biological balance in the ecosystem. At this stage, a large biomass can become troublesome, resulting in an increase in the herbivore population, competition or toxicity towards flora and fauna, alteration of the sediment, recycling of nutrients and pollutants in the ecosystem, nuisance for local residents and reduction of tourism (beaches degradation, chironomids, odors). Sooner or later, the water deteriorates, which may have a toxic effect on fauna including the commercial fish stocks.

Eutrophication problems have thus become a matter of major concern. Its management is neither a simple nor a cheap task. But, environmental and sustainability concerns may, in a not too distant future, override the lack of financial benefit. At any rate, underlayed action is required because in estuarine and potamologic milieus, potential land disposal arrangements are becoming rarer and costlier.

Control of eutrophication can only be reached effectively by drastic reduction of the total nutrient load of an overloaded water system. In order to be successful, only an integrated approach, based on a water body's nutrient mass balance and taking into consideration specific geographical, climatological and ecological conditions, can be effective. Moreover, it may take many years before recovery of a eutrophicated ecosystem, because the sediments constitute a complementary source of nutrients for macroalgae. But, prevention will prevent the nutrients from being discharged in the lagoons or in the sea. It will concern the waste treatment, agricultural mode change and treatment of gaseous effluent from polluting human activities.

Caleta Valdés is an area constituted by a set of Holocene and Pleistocene gravel beach ridges, which form part of a barrier spit system. Longshore drift has been predominantly north to south for the last 5700 years. Evolution of the area has been monitored during the last 28 years. In this period, the northern spit has been growing southward, and its rate has increased from 25-meter per annum (1971–87), to 89-meter per annum (1987–96). During the 1996–9 time span, growth has increased up to 167-meter per annum. This growth rate implies an average movement of approximately 1400 metric tons of gravel a day during the last four years. The growth rate during the time span under study can be represented by a polynomial equation of the third order. Spit evolution can be predicted from this equation. It is thus possible to suggest that Caleta Valdés is likely to close by 2002 (±). Such a morphological change will cause drastic changes in hydrodynamics, and environmental conditions due to changes in both water salinity and temperature.

In order to probe anisotropy of magnetic susceptibility (AMS) characteristics of tide-influenced sediments, AMS analyses and primary sedimentary structure observation and description were conducted on the borehole CM-97 samples from Changjiang delta, China. Primary sedimentary structure (cross-laminations) observation and description were based on a detailed examination of X-ray photographs of samples. Primary cross-laminations were found on 19 of 35 subcores, among which five subcores, A6, A7, B17, B30, and B38, have bidirectional cross-laminations. We found a total of 35 cross-laminations on the subcore sections of tide-influenced sediments, of which 14 were distributed on the five subcores with bidirectional cross-laminations. By their bidirectional dipping foreset laminae, the primary cross-laminations clearly showed bidirectional flow features of the environments in which these sediments formed. Comparing the paleocurrent directions shown by these cross-laminations with those indicated by the in situ AMS data, we found that more than 64% exhibited similar current directions, demonstrating that AMS can supply us with the true paleocurrent directions for such sediments. From the downhole paleocurrent changes inferred from the in situ AMS data, it was also clear that there were bidirectional flows during the deposition of these sediments and that sediments deposited in different environments had different change characteristics with respect to downhole paleocurrents. These differences among the muddy intertidal- to subtidal-flat sediments (unit 5), the Changjiang estuary central basin sediments (unit 6), and the delta front sediments (unit 8) may have resulted from the different hydrodynamic conditions of these sedimentary environments. Furthermore, stratigraphic unit 5 was subdivided into three parts based on downhole AMS characteristics, which may correlate with those subdivided according to downhole paleocurrent changes. Therefore, besides its long recognized role in paleocurrent determination, AMS can also be used to determine stratigraphic divisions and to reconstruct sedimentary paleoenvironments in detail.

The international data on tidal prism and cross-sectional area of tidal inlets and estuaries are examined as a basis for exploring the variability in the comparable UK data. The data are then used to evaluate the existing classification of estuary types; to present a number of relationships between the key bulk parameters of estuary volume, plan area, and cross-sectional area; and to test some theoretically derived relationships. The results suggest that the degree of Holocene sedimentation, and hence Holocene development, may explain much of the variability seen in the data, and this is not, as yet, fully accounted for in the theoretical relationships.

We conducted field and culture experiments to study the effects of arbuscular mycorrhizal (AM) fungi on the establishment of the alien plant Oenothera laciniata (Onagraceae) in a coastal sand dune in Japan. We examined the distribution of plants, AM fungal colonization of their roots, and fungal spore density in the soil of a coastal sand dune at Keinomatsubara, Hyogo Prefecture, western Japan. Of the nine dominant plant species at the study site, six species, including O. laciniata, were heavily colonized by AM fungi. The spore density tended to decrease from inland toward the shoreline, but there were no significant relationships between the level of AM fungal colonization and spore density. Seedlings of O. laciniata inoculated with AM fungi, as well as uninoculated seedlings, were transplanted to the study site. No significant difference in survival rates was detected between the two groups of seedlings. We also examined the effects of AM infection and nutrient (N and P) application on plant growth in a pot culture experiment. The results suggested that the growth of O. laciniata was limited mainly by N availability and that AM mycorrhizae had little effect on the establishment of the plant on the coastal sand dune.

The generation of tidal asymmetries in estuaries is analyzed by examining the differences in celerity at high and low tide. An analytical expression for the difference between ebb and flood durations is introduced and applied to a cross section composed of a channel flanked by tidal flats. The expression depends on the cross-sectional average of the celerity, for which two approximations are proposed and verified with a numerical model. Results confirm that tidal flats enhance ebb dominance, whereas large tidal amplitudes promote flood dominance. Maximum ebb dominance occurs for tidal flats at or above mean water level, depending on tidal amplitude and the extent of the tidal flats. Finally, qualitative arguments indicate that friction also enhances flood dominance.

“Sabkha” is a term used to describe the coastal flats and salt marches deposited in lagoonal areas under arid conditions. In this study, water and sediment samples (n = 51 and 182, respectively) were collected from sabkhas systems of the Red Sea coast, which extends between Jeddah city and the town of Yanbu Al-Bahar and is bounded by latitudes 21°30′ and 24°00′N and longitudes 38°00′ and 39°30′E. The collected sediment samples were subjected to sedimentological and mineralogical analyses using grain size and X-ray diffraction techniques. The water samples were subjected to hydrochemical analyses using several standard procedures. The study found that climatic conditions in the Red Sea coastal plain sabkhas lead to the formation of marine brines of magnesium-sodic to chloride type with neutral pH value. Because of the evaporation of the groundwater, the evaporite minerals, especially aragonite, halite, and gypsum, were precipitated. The present study shows that this resulted in an increase in the Mg ²/Cl⁻¹ ion concentrations and the formation of protodolomite mainly in the sediments of the supratidal flats. The reported results indicate that the precipitation of the evaporite minerals and the early diagenetic dolomitization caused decrease in sulfate concentration and the Mg ²/Ca ² ratios in the water of the supratidal flats. The study also found that more than 50% of the Na ¹ ions were precipitated as halite as indicated from the average value of Na ¹/Cl⁻¹ ratios, which is lower than 0.75. The absence of clay beds in the sediments overlying the water table is probably the reason for the similar potassium ion concentrations in both upper intertidal and supratidal flat waters in addition to the Red Sea water. The relatively low concentrations of sulfates in the water of the supratidal flats of the studied sabkhas in comparison with their concentrations in the water of the upper intertidal flats are probably due to the precipitation of gypsum in the sediments of the supratidal flats of these sabkhas. The slightly high concentrations of bicarbonates in the water of the studied sabkhas are due mainly to the precipitation of carbonates, especially aragonite, as well as to the low pH values of these waters. The reported results can be considered as documentation of the hydrogeochemical characteristics of the Red sea sabkhas and could be useful for planners and researchers interested in the Red Sea coastal systems.