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Abstract: The coastal area of Samborombón Bay ends in a short cliff which, during the last decades, has been undergoing an increased retrogression of approximately 8.2m decade−1. The aim of this paper is to investigate whether this accelerated erosion can be related to an apparent wind-wave climate change, which has been recently reported for the Río de la Plata region. A numerical study with SWAN wave model for the period 1971–2005 drives to positive trends in the frequency of occurrence and heights of waves propagating from the E and ESE. Particularly, the number of cases of high waves from those directions displays a significant increment. In addition, previous papers have reported an increment of the frequency, height and duration of the storm surges in the Río de la Plata, so as a rise of the mean sea level in the region. It is concluded that the combination of those three factors acting together constitutes a powerful and effective mechanism which is likely responsible for the observed increasing erosion in Samborombón Bay. [Copyright &y& Elsevier]

Abstract: This paper investigates the effect of future sea-level rise (SLR) on the tides of the northwest European Continental Shelf. The European shelf tide is dominated by semidiurnal constituents. This study therefore focuses primarily on the changes in the M2 tidal constituent and the spring and neap tidal conditions. The validated operational Dutch Continental Shelf Model is run for the present day sea-level as well as 2 and 10m SLR scenarios. The M2 tidal amplitude responds to SLR in a spatially non-uniform manner, with substantial amplitude increases and decreases in both scenarios. The M2 tidal response is non-linear between 2 and 10m with respect to SLR, particularly in the North Sea. Under the 2m SLR scenario the M2 constituent is particularly responsive in the resonant areas of the Bristol Channel and Gulf of St. Malo (with large amplitude decreases) and in the southeastern German Bight and Dutch Wadden Sea (with large amplitude increases). Changes in the spring tide are generally greater still than those in the M2 or neap tides. With 2m SLR the spring tidal range increases up to 35cm at Cuxhaven and decreases up to −49cm at St. Malo. Additionally the changes in the shallow water tides are larger than expected. With SLR the depth, wave speed and wave length (tidal resonance characteristics) are increased causing changes in near resonant areas. In expansive shallow areas SLR causes reduced energy dissipation by bottom friction. Combined these mechanisms result in the migration of the amphidromes and complex patterns of non-linear change in the tide with SLR. Despite the significant uncertainty associated with the rate of SLR over the next century, substantial alterations to tidal characteristics can be expected under a high end SLR scenario. Contrary to existing studies this paper highlights the importance of considering the modification of the tides by future SLR. These substantial future changes in the tides could have wide reaching implications; including for example, correctly calculating design level requirements for flood defences, the availability of tidal renewable energy and dredging requirements. [Copyright &y& Elsevier]

Abstract: This paper provides estimates of rates of change in mean sea level around the English Channel, based on an extensive new hourly sea level data set for the south coast of the UK, derived from data archaeology. Mean sea level trends are found to vary by between 0.8 and 2.3mm/yr around the Channel. The rates of mean sea level change are calculated by removing the coherent part of the sea level variability from the time series of annual mean sea level before fitting linear trends. The improvement in accuracy gained by using this approach is assessed by comparing trends with those calculated using the more traditional method, in which linear trends are fitted directly to the original records. Removal of the coherent part of the sea level variability allows more precise trends to be calculated from records spanning 30 years. With the traditional approach 50 years is required to obtain the same level of accuracy. Rates of vertical land movement are approximated by subtracting the mean sea level trends from the most recent regional estimate of change in sea level due to oceanographic processes only. These estimated rates are compared to measurements from geological data and advanced geodetic techniques. There is good agreement around most of the UK. However, the rates estimated from the sea level records imply that the geological data suggest too much submergence along the western and central parts of the UK south coast. Lastly, the paper evaluates whether the high rates of mean sea level rise of the last decade are unusual compared to trends observed at other periods in the historical record and finds that they are not. [Copyright &y& Elsevier]

Many estuaries worldwide are modified, primarily driven by economic gain or safety. These works, combined with global climate changes heavily influence the morphologic development of estuaries. In this paper, we analyze the impact of human activities on the morphodynamic developments of the Scheldt Estuary and the Wadden Sea basins in the Netherlands and the Yangtze Estuary in China at various spatial scales, and identify mechanisms responsible for their change. Human activities in these systems include engineering works and dredging activities for improving and maintaining the navigation channels, engineering works for flood protection, and shoreline management activities such as land reclamations. The Yangtze Estuary is influenced by human activities in the upstream river basin as well, especially through the construction of many dams. The tidal basins in the Netherlands are also influenced by human activities along the adjacent coasts. Furthermore, all these systems are influenced by global changes through (accelerated) sea-level rise and changing weather patterns. We show that the cumulative impacts of these human activities and global changes may lead to exceeding thresholds beyond which the morphology of the tidal basins significantly changes, and loses its natural characteristics. A threshold is called tipping point when the changes are even irreversible. Knowledge on such thresholds or tipping points is important for the sustainable management of these systems. We have identified and quantified various examples of such thresholds and/or tipping points for the morphodynamic developments at various spatial and temporal scales. At the largest scale (mega-scale) we consider the sediment budget of a tidal basin as a whole. A smaller scale (macro-scale) is the development of channel structures in an estuary, especially the development of two competing channels. At the smallest scale (meso-scale) we analyze the developments of tidal flats and the connecting channels. [ABSTRACT FROM AUTHOR]

Rigorous assessments of ecological classification schemes being applied to submerged environments are needed to evaluate their utility as management tools. Verification that a scheme can quantitatively capture habitat and community variation would be of considerable value to individuals responsible for making difficult management decisions relevant to widespread environmental challenges including those in fisheries, preservation or restoration of critical habitats, and climate change. In this paper, an assessment approach that evaluates a scheme by treating it like a quantitative statistical model is presented. It couples two direct gradient, multivariate statistical techniques, multivariate regression trees (MRT) and redundancy analysis (RDA), with a modelling protocol involving model formulation, model selection, parameter estimation, and measurement of precision to produce a very flexible strategy for analyzing structure in ecological data. To illustrate the proposed approach, the assessment focused on benthic infauna and evaluating the Folk grain size classification scheme, along with some alternative grain size models. Analysis of data sets revealed that while it was fairly easy to uncover biotic-environmental relationships that were over-fitted, the community structure inherent in the data tended to be robustly discernible and preserved across all grain size models, but rigidly parameterized models (i.e., a one size fits all approach for grain size characterization with fixed boundaries) were generally ineffective. The proposed approach provided a clear, detailed, and rigorous assessment of Folk and several alternative models and can be used for the quantitative evaluation of existing ecological classification schemes and/or in the development of new schemes. [ABSTRACT FROM AUTHOR]

This paper describes the fauna associated with the gorgonians Paragorgia arborea (530 colonies), Primnoa resedaeformis (370 colonies) and Paramuricea placomus (68 colonies) and the sea pens Kophobelemnon stelliferum (584 colonies), Virgularia mirabilis (114 colonies), Funiculina quadrangularis (278 colonies) and Pennatula phosphorea (36 colonies) recorded by video from 18 locations on the Norwegian continental margin. The fauna associated with gorgonians was more diverse than that of the sea pens, with 21 and 12 taxa recorded. P. arborea had the highest number of associates; in total ~38% of the colonies had associates on them. Amphipods dominated numerically contributing with 72% to the total number of taxa observed. Shrimps and the basket star Gorgonocephalus sp. were frequently observed on all gorgonian species. Rarefaction analysis indicated that the number of associated taxa was richest for P. resedaeformis . The fauna associated with the sea pens consisted mainly of shrimps and ophiuroids, for which the sea pens play a key role as a shelter and/or as a feeding platform. The ophiuroid Asteronyx loveni was only observed on F. quadrangularis , which is used as a platform to reach better feeding conditions. The squat lobster Munida sp. was often observed close to the sea pen K. stelliferum which presumably offer shelter against predators. We argue that both sea pens and gorgonians play an important role as a habitat, and that a better understanding of their ecological importance is essential to develop sound scientific advice on sustainable habitats and fisheries management of deep-water ecosystems. [ABSTRACT FROM AUTHOR]

The paper documents dynamics of the middle Adriatic region, and is based on computation of relative geostrophic currents from temperature and salinity data taken along the Palagruža Sill transect between 1957 and 2010. The strongest westward current is found in the central part of the sill, corresponding to the offshore deflected Eastern Adriatic Current (EAC). The Western Adriatic Current (WAC) is, as expected, found in the southern part of the measured transect. The WAC is most significant during the summer season and exhibits stronger variability than the EAC due to the frequent growth of eddies within it. Long-term trends in both the central and southern parts of the sill oppose mean currents, indicating the weakening of the EAC and WAC and therefore of the entire Adriatic thermohaline cell. These opposing trends have not been reproduced by a climate model. [ABSTRACT FROM AUTHOR]

Recent improvements in satellite altimetry data correction terms are encouraging studies of the remote sensed sea level anomalies (SLA) progressively closer to the coast and over shallow continental shelves. In this paper we describe and discuss the SLA trend and variability at seasonal and interannual time scales in the southeastern South American continental shelf influenced by the Río de la Plata estuary and the Patos Lagoon fresh waters. The spatio-temporal coverage of the gridded altimetry SLA data allows identify several variability patterns and the associated physical processes. On seasonal time scales, the combination of the solar radiation and wind forcing cycles accounts for up to 98% of the variability. Seasonal variability of the wind is responsible for a difference of up to 16 cm between the southern (Argentinean) Río de la Plata estuary coast and the Uruguayan and southern Brazilian coasts. On interannual time scales, positive/negative SLA anomalies are coherent with El Niño/La Niña events. Finally, a significant positive trend of up to 5 mm yr −1 is found in all the study area except in the region around the Patos Lagoon (Brazil) and part of the Río de la Plata. Besides the local relevance of the results, this study indicates that satellite altimetry data are accurate enough to unveil SLA spatio-temporal patterns close to the coast and over continental shelves in the mentioned time scales. [ABSTRACT FROM AUTHOR]

This paper describes the work of sea level data rescue, digitization, reduction to a common vertical reference and quality control leading to the reconstruction of a time series for the Atlantic NW coast of France (Pertuis d’Antioche). A total of 14 sea level data sets were merged to build a consistent composite time series of monthly and annual mean sea levels spanning 188 years (1824–2011). The estimation of a linear trend for this time series yields a relative mean sea level rise for the region of 1.3±0.1mmyr−1 for the whole study period, and 1.9±0.2mmyr−1 for the 20th century, consistent with previous studies in the region. This work evidences the importance of data archaeology in the pursuing of historical information useful for sea level studies, which can be relevant for climate research and coastal management amongst other applications. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, it was hypothesized that coastal upwelling increases in western boundary current influenced regions due to global warming. A state-space decomposition of the alongshore wind stress time-series exhibited an intensification during the “upwelling season” in the last 20 years (1988–2008), which agrees well with the above hypothesis. However, when applying the same decomposition to a temperature time-series at Qinglan station (located at the eastern Hainan coast) over the past 50 years (1960–2006), a negative trend was found. This indicates that the simple relation between alongshore wind stress and upwelling strength is not valid in the study area, but that other non-local factors might influence the inter-annual variability of the upwelling significantly. To identify these possible non-local effects, results of a model simulation were analyzed. From these model data an acceptable relationship between the non-locally driven western boundary current and the strength of the upwelling can be inferred. Furthermore, an “SST (sea surface temperature) upwelling index” was introduced, calculated by the simulated offshore–onshore temperature difference. This index exhibits a good correlation with the Qinglan “observational upwelling time-series”, demonstrating that the latter is a good indicator of the upwelling trend. Finally, it is shown that inter-annual oscillations of employed temperature records correlate well with the El Niño signal. [Copyright &y& Elsevier]

Abstract: An assessment of the complex evolution of climate change signals in the Irish Sea over the 21st century is presented in this paper. Potential impacts of climate change on the local hydrography are explored and interrelationships between fundamental oceanographic shelf sea phenomena investigated. A regional ECOMSED ocean model is used to downscale a 120-year period (1980–2099) of the SRES A1B scenario experiment from a global ocean model. A detailed regional analysis shows that local climate changes may be significantly different from the expected global changes. This research suggests that in the future the Irish Sea will be warmer with sea surface temperature increase of around 1.9°C. Maxima and minima annual temperatures will occur around 2 weeks later each year relative to the present climate. Geographically, shallow waters along the coastline and in the eastern Irish Sea will exhibit strongest warming due to increased heat uptake during summer and autumn and reduced heat loss in spring and winter. Warming in the deep channel in the western Irish Sea will be generally weaker with seasonal variability subdued due to a large heat storage capacity. The warming will be largely stored in the surface layer of the water column leading to strengthening of stratification and a considerable decrease in the thickness of the mixed layer. The western Irish Sea gyre will become stronger and result in substantial reinforcement (>30%) of southward currents along the east coast of Ireland. Net northward flow in future predicted climate conditions will be maintained at the current annual rate. Steric sea level is projected to rise by 0.31m during the 21st century, leading to an overall projected sea level rise of approximately of 0.47m. Future changes to oceanographic parameters, flushing times and hydrodynamics of the Irish Sea are likely to alter the habitat and distribution of marine species; the finding of this research are therefore of great interest to ecologists and the fishery industry. [Copyright &y& Elsevier]

Abstract: Changes in the ocean tide during the 20th century have been reported for several parts of the world by different authors. However, it has not always been clear whether the observed changes have been local or regional in scale. This paper reports on a survey of tidal changes in recent decades using a quasi-global data set of tide gauge information. Little evidence has been found in Europe or the Far East (including Australasia and Asia) for the extensive regional changes to the main tidal constituents reported recently for N America. However, evidence for change in smaller regions can be identified wherever the density of tide gauge information allows. Therefore, it seems that tidal changes may be commonplace around the world, although not necessarily with large spatial scales. All of the reported changes have been difficult to explain. However, it is hoped that quasi-global surveys such as the present one may eventually provide further insights. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the role of atmospheric forcing in modifying the pathways of riverine water on the Laptev Sea shelf, using summer-to-winter hydrographic surveys from 2007 to 2009. Over the two consecutive winter seasons of 2007–2008 and 2008–2009 in the area of the winter coastal polynya, our data clearly link winter surface salinity fields to the previous summer conditions, with substantially different winter salinity patterns preconditioned by summer atmospheric forcing. In the summer of 2007, dominant along-shore westerly winds in the cyclonic regime force the Lena River runoff to flow eastward. In contrast, in the summer of 2008, dominant along-shore easterly winds over the East Siberian Sea and on-shore northerly winds over the Laptev Sea in the anticyclonic regime lock the riverine water in the vicinity of the Lena Delta. Over the coastal polynya area in the southeastern Laptev Sea these patterns precondition a surface salinity difference of 8–16psu between the winters of 2008 and 2009. Overall, this indicates a residence time of at least half a year for riverine water on the Laptev Sea shelf. Future climate change associated with an enhanced summer cyclonicity over the eastern Arctic may turn more riverine water eastward along the eastern Siberian coast, resulting in weaker vertical density stratification over the Laptev Sea shelf, with possible impact on the efficiency of vertical mixing and polynya dense water production. [ABSTRACT FROM AUTHOR]

The Lagoon of Nador (Morocco) has been subject to relevant man-made changes in recent years, which consisted of closing the inlet and opening a new one, wider and deeper, with long lateral jetties. In this paper, we study some of the consequences of this modification, using a 3D hydrodynamic model that allows a comparison of the two configurations (old and new inlet). This would be not possible analysing only the observations and the approach we followed is a general method that can be applied wherever man-made or natural changes affect a coastal system. We have created two numerical grids, one with the old inlet and one with the new inlet, both covering the entire lagoon and a wide part of the coastal area. Using these two configurations, fully baroclinic simulations were run for one year. The results show a significant increase of the tidal amplitude and of the water circulation inside the lagoon, with a tidal prism four times larger. The change of the tidal asymmetry from positive to negative values (−0.7 in the inlet) causes a shift toward the ebb dominance, with implications for the mid-term morphological evolution. With the new inlet the water renewal time of the lagoon decreased from 57 to 15 days and the water temperature got warmer in winter (+1 °C) and colder in summer (−2 °C). As a consequence of this, the evaporation lowered and the salinity reduced by 0.8 PSU. The seasonal variability of the water renewal time shows that the tidal forcing, the baroclinic circulation and the wind contribute to the mixing processes. The mixing capacity of the lagoon (0.7) did not change because it is an intrinsic property of the lagoon morphology and of the atmospheric forcing. Finally, we found that the change of the water renewal time, with the new inlet, is higher than the change predicted, with the old inlet, under the RCP8.5 climate change scenario. • The opening of the new inlet lowers significantly the water renewal time, increases the exchange with sea so that the thermohaline characteristics of the lagoon are more similar to the sea. • The mixing efficiency of the lagoon did not change significantly, because it depends much more on the surface boundary conditions (wind forcing), rather than the lateral boundary conditions. • The new inlet changed the characteristic of the tidal signal from flood dominated (with the old inlet configuration) to ebb dominated. • The residual circulation is significantly influenced by the tidal jet that expands into the lagoon and the dominant N-E wind. • This anthropogenic change lowers the renewal time of the lagoon as like the climate change, but in a much shorter time and with higher magnitude. [ABSTRACT FROM AUTHOR]

Global and climate changes are subject to scientific, societal and political debates. Recent observational evidence and results of global climate models have identified the circumpolar North as a region particularly susceptible to future climate change. To understand and assess the consequences of these changes for environmental and societal components of the European Arctic, the Barents Sea Impact Study (BASIS), an EU-funded integrated regional impact study (IRIS) has been carried out (ENV4-CT-97-0637). In common with global integrated assessments (IAs), IRISs also take a holistic view on climate change and its impact. Contrary to IAs, however, IRISs adopt a regional to sub-regional spatial scale. BASIS was carried out by an interdisciplinary team of specialists from 13 institutions in 6 countries. Major results pertain to impacts of possible climate change on marine and terrestrial ecosystems, freshwater hydrology, marine trace gas budgets, forestry and fishery. However, in this paper we focus on the major methodological aspects of an IRIS in general and on methods applied in BASIS in particular. [Copyright &y& Elsevier]

Abstract: This paper discusses the application of a simple algorithm for the buffering of fines in a sandy seabed. A second layer is introduced in which fines may be stored during calm weather and from which fines may be resuspended during storms. The algorithm is applied first in a one-dimensional vertical (1DV) point model at a location in the North Sea, Noordwijk 10, 10km offshore. It is able to reproduce the observed temporal variability of suspended particulate matter satisfactorily. Apart from the second layer, also the applied first order erosion rate is an important element of the algorithm. This allows for an equilibrium sediment mass per unit area for any combination of bed shear stress climate and sediment supply. The classical Partheniades–Krone formulation with zero-order erosion (i.e. an erosion rate that is independent from the sediment mass per unit area) does not have such equilibrium. As a next step, the algorithm is incorporated into a 3D model for suspended particulate matter (SPM) transport in the Dutch coastal zone. It is demonstrated that the model is able to reproduce the observed spatial and temporal variability reasonably well. An essential feature of the 3D mud model is that it is sufficiently fast to compute equilibrium bed composition. This implies that the results are completely independent from the applied (uniform) initial conditions. Finally, the mud model is applied to assess the impact of a large-scale release of fines in the Dutch coastal zone. The computed impact turns out to be very sensitive to the assumed buffer capacity of the seabed. However, information on transient system response (such as the dissipation of a sediment pulse in the system) from which the buffer capacity may be estimated is most often lacking. For the time being, estimates on the residence time of fines in the seabed and its mixing depth are derived from the literature. Additional field and laboratory test on the exchange mechanisms of fines between the water column and a sandy seabed are recommended. [Copyright &y& Elsevier]