The 18.6-year nodal tide is a component of all tide gauge records. It can affect estimates of sea level acceleration, in particular for tide gauge records with lengths of less than 60 years. We provide an analytic solution that shows the effect of the nodal tide on estimates of sea level trend and acceleration. By adding a term to the least squares formulation used to estimate sea level trend and acceleration, we can account for the nodal tide and eliminate its effect on the estimate. Using representative world-wide tide gauge records, we demonstrate that accounting for the nodal tide can improve estimates, particularly of acceleration.

Analyses of the progressive multidecadal trends and climate-controlled annual variations in mean sea levels are presented for nine tide-gauge stations along the coast of the U.S. Pacific Northwest: Washington, Oregon, and Northern California. The trends in relative sea levels are strongly affected by the tectonics of this region, characterized by significant alongcoast variations in changing land elevations measured by benchmarks and global positioning system data. These combined data sets document the existence of both submergent and emergent stretches of shore. The Pacific Northwest sea levels are also affected by variations in the monthly mean seasonal cycles, with its extreme water levels occurring in the winter during strong El Niños. To quantify this climate control and to derive improved multidecadal sea-level trends, separate evaluations of the winter and summer-averaged measured water levels have been undertaken. The resulting pair of linear regressions for each tide gauge shows a consistent difference in the mean water levels over the years, at their highest during the winters, reflecting the total magnitude in the seasonal cycle of water levels. Of importance, the degree of scatter in the summer averages is reduced compared with the annual averages, yielding sea-level trends that generally have the highest statistical significance. In contrast, the winter records emphasize the extreme water levels associated with strong El Niños, yielding a predictive correlation with the Multivariate El Niño/Southern Oscillation Index. Both trends in relative sea levels and extremes in the winter monthly elevations produced by El Niños are important to the Pacific Northwest coastal hazard assessments, combining with the multidecade increase in wave heights measured by buoys. With these multiple processes and their climate controls, the erosion hazards are projected to significantly increase in future decades.

The characteristics of tidal constituents along the nearshore waters of Karnataka, west coast of India, are described. These are based on the sea level data measured at three locations by the Valeport wave and tide gauge during the presummer monsoon period. The objective of the study is to identify the tidal and nontidal variations along the coast. Analysis shows that astronomical tides are responsible for most of the observed sea level variability along the Karnataka coast. Ninety-seven percent of the variation in measured sea level at Honnavar and Malpe and 96% of the sea level variation at Kundapur was due to tide. The observed nontidal sea levels were related to local wind forcing. The study shows that when the wind from the south was strong, a rise in sea level was observed, and when the wind from the north was strong, a fall in sea level was observed. Correlation between the alongshore component of wind and nontidal sea level was 0.54 at Malpe and 0.48 at Honnavar. The nontidal sea level variation was found to vary according to the significant wave height. High residuals of sea level were found during high waves. Amplification of shallow-water constituents were relatively high compared with other constituents from south to north along the study area.

Sea surface salinity (SSS) is critical for studying biological and physical processes in the ocean, such as the global water balance, ocean currents, and evaporation rates. The water and heat fluxes associated with precipitation and evaporation over global oceans are fundamental in regulating climate and weather. Yet measurements of global SSSs are sparse and do not show the required temporal and spatial variability of SSS distributions. Airborne microwave radiometers, such as the Scanning Low-Frequency Microwave Radiometer (SLFMR) and the Salinity, Temperature, and Roughness Remote Scanner (STARRS), have been used successfully to map SSS and its variability, but only in estuaries and coastal waters. Since 2009, SSS has been measured from satellite orbit by the European Soil Moisture and Ocean Salinity satellite, which is designed to provide synthesized SSS maps with a high accuracy. Other salinity-related satellites are being developed, such as Aquarius, which will provide the global view of salinity variability needed for climate studies. The objectives of this paper are to review remote sensing techniques for mapping SSS and to demonstrate the application of microwave radiometry by presenting two case studies.

Shoreline change rates of Point Pelee National Park, Ontario are estimated for the period 1959–2004 using orthoair photos. The eastern side of the park had varying recession regardless of Lake Erie water-level changes, especially in Northeast Beach, where it averaged −3.14 m/y. The western side of the park generally exhibited accretion and had an inverse relationship with Lake Erie water levels. Longer duration of ice coverage during winter, favourable topography, and sedimentary conditions led to the observed difference in shoreline response. Future climate change patterns are expected to result in lower lake levels and less winter ice coverage, both of which will likely result in a net loss to the park's land habitat.

We monitored salinity and temperature in pools at different elevations in two marshes on the Bay of Fundy to assess variability in pool environments and how climate change might affect these ecosystems. Water temperatures reached a maximum of 36.1°C, and ice covered pools in the winter. Ice lifting out of ponds in the spring scoured bottoms. Salinity ranged from 4 to 41. Environmental variability was mainly driven by weather. Variability in pool temperature declined with decreasing elevation. Regular tidal flooding at lower elevations moderated both temperatures and salinity. Variability in pool salinity was greatest in the middle marsh region, since proximity to groundwater also moderated salinity at high elevations. Projections of milder winters should reduce formation of ice in pools, resulting in decreased scour, and possibly shallowing of pools. This, accompanied by projected increases in extreme weather, will increase salinity variability, thus increasing stress to organisms in an already stressful environment.

This study presents results of a human impact investigation of large-scale construction projects on sedimentation trend and morphologic changes in the Ganghwa tidal flats over 10 years using time-series waterlines from Landsat thematic mapper/enhanced thematic mapper. Waterlines were extracted from remotely sensed images. These images are useful for studying changes in coastlines and tidal flat topography. A reference digital elevation model (DEM) was constructed; then actual waterlines from satellite images were compared with modeled waterlines from the reference DEM. Systematic comparison with respect to horizontal differences between the two waterlines provided information on local conditions of sediment trends within the study area. Seaward or landward migration of waterlines was a clear indication of the change in sedimentation pattern. Deposition has been dominant at the main channel between the southern Ganghwa and the Yeongjong tidal flats, whereas erosion has been dominant at the eastern lower tidal flat. These sedimentation patterns complied with field observations along two survey lines and with the result from depth-sounding data. Deposition narrowed the channel and created a slightly more meandering shape. A hydrodynamic model anticipated a significant change of ocean current as a result of the coastal construction projects, and the modeling result matched well in terms of current conditions with the present sedimentation pattern analyzed by waterline comparison. A series of coastal construction projects in this area clearly affected the local hydrodynamics of tide and currents to a large extent and resulted in the changes of sedimentation trends during a decade, and it is necessary to keep the monitoring area to understand long-term impacts initiated by human activities within a relatively short period. Although it was not possible to estimate the total volume of sediment transportation with this method, trends of sedimentation processes within tidal flats can be effectively deduced.

Future sea-level rise will increase coastal flood risk in the U.K., yet the hazard uncertainties associated with such future risk estimates have not been fully explored. The sensitivity of coastal flood-risk mapping to future uncertainties was investigated by propagating ranges of plausible parameters through a LISFLOOD inundation model of a significant historic flood event to the North Somerset (U.K.) coast. Mean sea-level rise (including land movement) was found to have the greatest effect on the extent of flood inundation. Analysis of the latest research into the future storm-surge climate of the U.K. indicates no change above natural variability, thus, future, extreme water-level estimates (for the U.K.) should be based on observations and not Regional Circulation Models until research indicates otherwise. Evidence suggests that the current approach of forcing the inundation model with an extreme water level of a constant return period is incorrect. This uncertainty of the peak storm tide height along the coastline had a significant effect on our results. We present a new boundary-forcing technique to force the inundation model with (method C), based on the spatial characteristics of real events, which can account for the natural storm-surge variability. Indeed, if sea-level rise is included with method C, a great deal of the uncertainty surrounding such a future flood-hazard estimate can be quantified and communicated clearly and effectively.

Besides protection, the variability of assemblages in a marine reserve can result from the geographical features of the locations. Islands present within a marine protected area (MPA) offer an extremely valuable system to test the hypotheses of large-scale spatial patterns in assemblages, particularly when patterns on the islands were contrasted with those of the mainland. In fact, besides the natural causes of variability, insular locations are generally less accessible to humans than those on the mainland, with changing levels of accessibility, on the basis of the distance from the coast. This study examined the interactive effect of protection and geographical siting at Tavolara–Punta Coda Cavallo MPA in Sardinia, Italy, on gastropod species subjected to human harvest. Rocky-shore gastropod assemblages were sampled at locations with different level combinations of protection and accessibility. Results highlighted that assemblages in the MPA have been more significantly influenced by the geographical siting of the locations rather than by protection, as the larger dissimilarities were observed between the mainland and island locations. These results can have important implications for the conservation of marine coastal assemblages, and provide important quantitative information for future estimation of the effects of protection of MPAs. Further, they indicate that the inclusion of representative assemblages within the MPA systems requires targeting rocky shores both on the mainland and on islands, thus providing important tools to improve conservation strategies.

The Darss-Zingst Peninsula on the southern Baltic Sea was formed after the Littorina transgression onset about 8000 cal. y BP. It originated from several discrete islands, has been reshaped by littoral currents and wind-induced waves during the last 8000 y, and evolved into a complex lagoon system as seen today; thus, it may serve as an example to study coastal evolution under long-term climate change. A methodology for developing a multiscale process-based morphodynamic model for simulation of decadal to centennial evolution of a wave-dominated coastal environment is presented here. The model consists of eight main modules. The two-dimensional vertically integrated current module, the wave module, the bottom boundary layer module, the sediment transport module, the cliff erosion module, and the nearshore storm module are real-time calculation modules that aim to solve the short-term processes. A bathymetry update module and a long-term control function set, in which the “reduction” concepts and techniques for acceleration of morphological update are implemented, are integrated to extend the effects of short-term processes to a longer-term (yearly) scale. Successful model validation demonstrates that it is capable of simulating the long-term morphological evolution of the southern Baltic coast. Model results indicate that coastline change of the Darss-Zingst Peninsula is dominated by mechanisms that act on different timescales. The coastlines of Darss and Hiddensee Island are mainly reshaped by long-term effects of waves and longshore currents, while coastline change of the Zingst area is a combination of long-term effects of waves and short-term effects caused by extreme wind events.

Interactions between human manipulations and landscape processes can form a dynamically coupled system because landscape-forming processes affect humans, and humans increasingly manipulate landscape-forming processes. Despite the dynamic nature of sandy barrier islands, economic incentive and recreational opportunities attract humans and development. Storm-driven sediment-transport events that build barrier islands constitute hazards to humans and infrastructure, and manipulations aimed at preventing or mitigating such events link human actions and long-term island morphodynamics. To explore how the behavior of a natural barrier island differs from one in which humans are dynamic system constituents, we use a numerical model of storm-driven sediment redistributions within the shoreface/island/back-barrier system and human rearrangements of sediment within the subaerial barrier island. In a modeled natural system, periods of dune growth and island stability, initiated by stochastic lulls in storm activity, alternate with stormy periods, in which shoreline erosion and frequent overwash regulate dune heights. When humans are included in the model, overwash deposits are removed from the island, and artificially high dunes are rebuilt. These manipulations tend to filter moderate overwash events. However, with shoreline erosion and rising sea level, these manipulations promote lower and narrower islands in the long term, so that when dunes are overtopped, the sediment redistributions are more severe. Thus, the coupled human/barrier system exhibits wider swings between increased island stability and sudden island displacements. Increasing the height of artificially maintained dunes increases the rate of island narrowing and, therefore, infrastructure relocation, and increases the need for sediment to be imported from outside the system.

Tsunamis are rarely generated along passive continental margins and infrequently found in shallow shelf seas. However, a thorough study of old reports, newspapers, and other sources provided useful hints that a tsunami occurred in the North Sea Basin on June 5, 1858, with run-up values of up to 6 m along the W coast of Denmark. Reports by official authorities and eyewitnesses, mostly published directly after the event, refer to all the phenomena known from ancient and modern tsunamis: single waves approaching with a loud noise, wave groups separated by longer time spans, extremely long wave crests, withdrawal of the sea in front of the first wave, extraordinary wave/run-up heights during calm weather and sea, and much more. The arrival time of the first wave in an area from the southern English Channel to the W coast of Denmark hints at a tsunami source in the wider Biscay region or south of it, the tsunami waves travelling around the British Isles and entering the North Sea both from the NW, around Scotland, and from the SW, through the English Channel and Straits of Dover. Many wave events in the North Sea region are well known, but nothing similar has happened in the last 150 years or long before 1858, so there is no doubt that this extraordinary event was a tsunami and not another type of wave phenomenon.

The present contribution aims to provide an insight into the sediment dynamics of the Bay of Marseille (BoM), France, an area characterised by a mostly rocky, steep-sloped, and protected shoreline. In terms of sediment composition, the northern part of the study area is dominated by fines, whereas sands of mean grain size 0.2 < d₅₀ < 1 mm occur at most other locations. Posidonia oceanica meadows occupy many nearshore areas. Critical bed-shear stress was determined through tests in a unidirectional flume using 15 natural cores. Measured values ranged from 0.04 N/m² to 0.46 N/m² and were expressed as a function of the logarithm of d₅₀. Mud content had no observable effect on sediment cohesion, whereas a weak positive trend between critical shear stress and clay content was discerned. Autonomous benthic stations (Acoustic Doppler Current Profiler/Conductivity, Temperature, Depth/Turbidity/ALTUS Data Collection System) were deployed for periods of 2–3 months, and several suspension and erosion events were identified for significant wave heights exceeding 1.5 m. Grain-size trends showed that the protected BoM appeared to favour accumulation of sediments advected from the surrounding areas. The southern sector of the BoM was found to be the area with the highest sediment agitation and erosion rates but with weak transport trends. The northern sector, exposed to dominant SW waves, was shown to be the second most active area in terms of sediment dynamics, whereas the several Posidonia oceanica meadows and sheltered locations along the study area appeared to be possible sediment sinks. The latter included locations close to port installations and the western part of the Cortiou area, known to have water quality issues, which, according to the present findings, are linked to low sediment mobility and/or dispersion of pollutants.

Coastal areas of ecological importance, like tidal flats and salt marshes, are gradually decreasing because of large-scale coastal development projects, land reclamation, and so on. The Nakdong estuary is the most developed estuary in South Korea. The development of artificial tidal flats and salt marshes has been promoted as mitigation countermeasures. Previous studies evaluated artificial tidal flats and salt marshes for their degree of restoration of natural sites. In this paper, an in situ pilot plant of a tidal flat and a salt marsh was conducted to monitor and quantify bio-chemical indicators (biodiversity, population, and biomass of macro benthos; survival ratio of reeds; number of heterotrophic bacteria) and physicochemical characteristics. The content of dredged soil was varied to assess the difference and similarity between the natural and dredged soil. The degree of restoration and creation of ecological environmental zones is evaluated quantitatively with the use of a restoration index. The utility of this restoration index and the beneficial use of dredged soil are demonstrated for this pilot plant.

Habitat change of coastal wetlands caused by natural and anthropogenic factors is an important issue facing China. Large areas of coastal habitat are disappearing, and those remaining become vulnerable to anthropogenic impacts from industry, agriculture, aquaculture, urban development, and domestic waste. A question is whether the change of habitat area has an influence on boundary adjustments of natural reserves. The study reported in this paper applied remote-sensing images, and environmental and socioeconomic data to analyse the change of land use and land cover and habitat quality in an estuarine area and to identify the driving forces for these changes from 1988 to 2008. The results show that land use has changed significantly over this period. Cultivated lands occupying total area 35.96% decreased from 36,879.0 ha to 35,313.7 ha from 1988 to 1999. The area of settlements expanded from 11,305.1 ha in 1988 to 16,661.3 ha in 1999 and further to 23,258.6 ha in 2008. The areas of settlement, saltwater bodies, and unused land increased by 47.38%, 33.51%, and 16.66%, respectively, from 1988 to 1999. These trends continued from 1999 to 2008. The total average biomass in 2003 was far below the biomass of the same region in 1983 and the biological density also decreased sharply. The gross domestic product and population of the Dagang District grew continuously from 1993 to 2006 and was the main driving force of habitat change. The habitat quality of coastal wetlands is associated with natural reserve boundaries, which should be modified according to the actual protection status. The suggestion of boundary adjustment has also assisted the enhancement of habitat quality of coastal wetlands. This research emphasises the improvement of coastal environments through implementation of boundary adjustments.

The Holocene evolution of the Cabo Raso bay (Atlantic Patagonian coast) was reconstructed by means of geomorphological, stratigraphic, and palaeontological analyses, assisted by radiocarbon dating. Six beach ridges were individuated and mapped in the field, as well as some rocky erosional landforms, e.g., inner margins of marine terraces. Thanks to quarry sections, the internal structure of beach ridges, their relationship with continental deposits, and the fossil contents were determined. Two specimens of Aulacomya atra and Brachidontes purpuratus were radiocarbon dated at 6055 and 4500 ± 20 YBP, respectively. The bedrock outcrops at the base of an analysed section allowed us to associate the age of the samples collected to the elevation of the marine transgression surface upon which the entire deposit rests. Because a beach ridge is a regressive form, the elevation of the base of the dated deposit was assumed to be equivalent to or slightly lower than the maximum sea-level stationing, represented by the inner margin of the coheval marine terrace. The altimetric correlation between the base of the beach ridge dated at 6055 ± 20 YBP and the inner margin of the corresponding marine terraces allowed us to constrain the maximum Holocene marine transgression to about 3 to 2 m above sea level. This elevation for the maximum Holocene transgression is lower than that shown by most of the previous data for Patagonian coast, but it shows a crude agreement with recent estimates coming from geophysical models that report, for this area, a departure from the eustatic value of sea level, mainly caused by glacioisostatic process. This means that the employment of marine erosional landforms, associated with other multisource field data, proved to be determinant for reconstructing the sea-level variation in the Patagonian coast.

Uniola paniculata C. Linnaeus is a New World, tropical-, subtropical-, and temperate-zone, rhizomatous grass that is often a dominant species on foredunes and on the primary dune complex. Uniola paniculata L. has low freshwater-moisture requirements, tolerates aerosol salt spray, has low nutrient level requirements, tolerates high sand temperatures, and provides extensive sand coverage. Also known as sea oats, this grass inhabits mobile and semistable dune systems and plays a significant role in trapping sand and building primary dunes. Caryopsis production is low. However, germination is enhanced by cutting into the endosperm and leaching the caryopses. Northern populations require cold treatment before germination, but southern populations are not dependent on cold treatment before exposure to a germination protocol with a 35/25°C thermoperiod.