MERISTE, M.; KIRSIMÄE, K., and FREIBERG, L. 2012. Relative sea-level changes at shallow coasts inferred from reed bed distribution over the last 50 years in Matsalu Bay, the Baltic Sea.

Reed bed growth dynamics within the shallow Matsalu Bay, Baltic Sea, was studied over the last 50 years. There was expansive reed growth from the 1950s until the end of the 1970s, while over the last few decades the growth rate of the reed beds (establishment of new clones) has been considerably reduced or even ceased. Our results suggest that the distribution of the reed beds is controlled by mean sea-level variation superposed on a background of postglacial isostatic uplift. The reduced growth rate over the last decades is probably caused by an increase in the intensity of cyclonic activity (storminess) resulting in an increase of the average sea level, which has limited the suitable growth zones for the reed weakened by eutrophication.

Roostike levik Matsalu lahes ja Kasari deltas, Lääne-Eestis on viimase viiekümne aasta jooksul teinud läbi olulisi muutusi. 1050ndatest kuni 1970ndate aastateni iseloomustas Matsalu roostike kiire laienemine, kuid viimastel kümnenditel on roostike laienemine peatunud ning osades piirkondades võib täheldada juba roostiku taandumist. Roostike levikupilt Matsalu lahes viitab, et selle meresuunalist levikut kontrollib keskmine veesügavus Roostiku leviku peatumise arvatavaks põhjuseks on tänu pehmetele talvedele ja kasvanud (lääne-)tsüklonite aktiivsusele tõusnud keskmine veetase, mis piirab peamiste roostikuliikide efektiivset paljunemist.

FORD, M., 2012. Shoreline changes on an urban atoll in the central Pacific Ocean: Majuro atoll, Marshall Islands.

Majuro is the capital and most populated atoll in the Republic of the Marshall Islands and is located approximately 3700 km W–SW of Oahu, Hawaii. Like other atolls, Majuro is considered highly vulnerable to sea level rise. One of the widely perceived impacts of sea level rise on atoll islands is widespread chronic erosion. Using a combination of aerial photos and satellite imagery, this study presents an analysis of shoreline change over a 34- to 37-year study period, characterized by rapidly increasing population, coastal development, and rising sea level (3.0 mm y⁻¹). Results show most (93%) urban and rural villages have increased in size over the study period. Shoreline change analysis indicates the urban area has expanded both toward the lagoon and onto the ocean-facing reef flat. Shoreline change within the urban area of Majuro has been largely driven by widespread reclamation for a mix of residential, commercial, and industrial activities. Rural areas of the atoll typically have lower rates of shoreline change relative to those of urban areas. Analysis indicates that the rural lagoon shore is predominantly eroding, whereas the ocean-facing shore is largely accreting. Any shoreline response to sea level rise along the Majuro coast is likely masked by widespread anthropogenic impacts to the coastal system.

MONSERRAT, A.L.; CELSI, C.E., and FONTANA, S.L., 2012. Coastal dune vegetation of the Southern Pampas (Buenos Aires, Argentina) and its value for conservation.

Vegetation structure and species composition of southern Pampas coastal dunes were studied to evaluate their significance for conservation. The vegetation was described in 41 plots of 100 m² along four transects perpendicular to the coast. The floristic dataset was classified by two-way indicator species analysis. Vegetation distribution patterns were analysed in relation to the geomorphology and environmental factors. Fifty-one taxa (19 families) of vascular plants were recorded, with Asteraceae, Poaceae, and Fabaceae being the most abundant. The main vegetation groups obtained from the classification are related to distinctive geomorphology. (1) Upper beach and active dunes are habitats with extreme conditions, characterized by species-poor associations with low vegetation cover; group dominated by few shrubs and gramines like Panicum urvilleanum, Calycera crassifolia, and Senecio bergii. (2) Fixed/semifixed dunes are habitats with more stable substrate, characterized by dense vegetation, high species richness, and woody life forms; group dominated by Poa lanuginosa, Hyalis argentea var. latisquama, Oenothera mollissima, and Glycyrrhiza astragalina. (3) Hygrophilous communities are mostly associated with dune slacks with high herbaceous vegetation cover; group largely dominated by Cortaderia selloana, Typha sp., and Imperata brasiliensis. Detrended correspondence analysis shows that the major floristic variation follows a gradient from the beach inland. Also, there is a clear zonation pattern strongly associated with geomorphologic heterogeneity. The occurrence of threatened species (e.g., Adesmia filipes, Neosparton ephedroides) and endemic taxa (S. bergii and Baccharis divaricata) plus the high habitat diversity and plant species richness confers to the area special value for conservation. The ecological role of dune vegetation is discussed in conservation and management context.

La estructura de la vegetación y la composición de especies de las dunas costeras australes de la Región Pampeana fueron estudiadas para evaluar su importancia para la conservación de la biodiversidad. La vegetación fue descrita en 41 cuadrantes de 100m2 cada uno, a lo largo de cuatro transectas lineales perpendiculares a la costa. El set florístico fue clasificado mediante un análisis de dos vías de especies indicadoras (TWINSPAN). Los patrones de la distribución de la vegetación fueron analizados en lo referente a la geomorfología y a los factores ambientales. Dentro de los cuadrantes, se registraron 51 taxa (19 familias) de plantas vasculares, con Asteraceae, Poaceae y Fabaceae siendo los más abundantes. Los grupos principales de vegetación obtenidos de la clasificación se relacionan con distintivas localizaciones geomorfológicas: (1) playa superior y dunas activas son ambientes con condiciones extremas, caracterizados por asociaciones pobres en especies con baja cobertura vegetal; el grupo es dominado por pocos arbustos y gramíneas, como Panicum urvilleanum, Calycera crassifolia y Senecio bergii; (2) dunas fijas/semifijas son ambientes con un substrato más estable, caracterizado por vegetación densa, alta riqueza de la especie y formas de vida leñosas; el grupo fue dominado por Poa lanuginosa, Hyalis argen

LARSEN, P.F. 2012. The macroinvertebrate fauna of rockweed (Ascophyllum nodosum)–dominated low-energy rocky shores of the northern Gulf of Maine.

Sheltered, rockweed-dominated rocky shores are one of the most characteristic habitats of the northern Gulf of Maine. Rockweed, Ascophyllum nodosum, provides essential ecological services and recently has been subject to increasing commercial harvesting. This communication documents the associated macroinvertebrate fauna (>1.0 mm) of six characteristic rockweed shores along a 350 km gradient across the northern Gulf of Maine. Seventy-four putative taxa were identified. Numbers of species at each site ranged from 21 to 40. Arthropods, predominantly the barnacle Semibalanus balanoides, accounted for 70% of the individuals encountered. Densities per station ranged from 132 to 48,023 per m². Numerical analyses demonstrated that rockweed-dominated rocky shores of the northern Gulf of Maine are characterized by nine widely distributed taxa that represent 88.6% of the individuals. These nine are S. balanoides, oligochaetes, the isopod Jaera marina, the periwinkles Littorina obtusata and Littorina littorea, nematodes, the blue mussel Mytilus edulis, the amphipod Gammarus obtusatus, and nemerteans. Seven other taxa occurred widely at low densities. Cluster analysis of sites suggests a possible faunal break in midcoast Maine.

KAMBEKAR, A.R. and DEO, M.C., 2012. Wave prediction using genetic programming and model trees.

Wave predictions at specified locations can some times be conveniently made using empirical methods in preference to numerical ones in view of the empirical method's computational efficiency and lack of requirement for any exogenous information. This article describes one such attempt in which the time series prediction of waves was made through two alternative data driven methods: genetic programming and model trees. The significant wave height, H_s, and average zero-cross wave period, T_z, over different time steps in the future have been modeled as functions of a preceding sequence of the causal wind vector. The unknown functions have been captured in computer programs yielded by the genetic programming technique and also alternatively in the set of linear models produced by the technique of model trees. The measurements made by wave rider buoys at two locations along the Indian coastline have been analyzed to build and validate the models. Predictions have been made over the intervals of 1 to 4 days in the future based on a sequence of preceding wind vectors going back in time by the similar period as the prediction horizon. Applicability of such predictions at a nearby observation station is also explored. Although the overall performance of genetic programming was more attractive than that of model trees, both approaches performed well during the model testing exercise as evidenced by the high values of the correlation coefficient and the coefficient of efficiency and the low values of the mean absolute error, root mean square error, and scatter index.

WATSON, E.B. and BYRNE, R., 2012. Recent (1975–2004) vegetation change in the San Francisco Estuary, California, tidal marshes.

The establishment and monitoring of vegetation plots provide unique information on the spatiotemporal dynamics of plant distributions. In 1975, U.S. Geological Survey (USGS) scientists Atwater and Hedel established vegetation transects at six tidal marshes spanning the salinity gradient of the San Francisco Estuary, California, to establish a baseline against which future vegetation changes could be measured. Since 1975, estuarine salinity has increased because of water diversion, whereas sea level has risen at rates that exceed late-Holocene background levels. During the summers of 2003–04, we reoccupied these transects and measured plant composition to better understand the response of marsh vegetation to these hydrologic changes. Our results indicate that during the past 30 years, Sarcocornia pacifica, the most salt-tolerant plant species, increased in cover, whereas Schoenoplectus californicus, the least salt-tolerant plant species, decreased in cover. We hypothesize that increasing estuarine salinity resulted in these shifts. Additionally, Distichlis spicata has experienced large-scale replacement, predominantly by Schoenoplectus americanus. Because Distichlis spicata was found to be associated most strongly with high relative marsh elevations, we hypothesize that the decline in this species is a consequence of accelerated sea level rise. The vegetation changes observed in San Francisco Estuary marshes reported here are consistent throughout the estuary and have been observed in other studies and, therefore, serve as a guide to better understand the consequences of anthropogenically driven environmental change to estuarine wetlands.

ARIS, A.Z.; PRAVEENA, S.M., and Abdullah M.H., 2012. The influence of seawater on the chemical composition of groundwater in a small island: the example of Manukan Island, East Malaysia.

Manukan Island in Sabah, Malaysia, is characterized as a small, unique island where groundwater is a major source for domestic water and other water-related activities. Hydrochemical studies were carried out in the island with the objective of identifying the influence of seawater on the chemical composition of groundwater in Manukan Island via ionic ratios and saturation states. From the calculated ionic ratios, the chemical composition of groundwater in the study area in general is influenced by seawater intrusion. The Na/Cl ratios ranged from 0.10–2.70, implying that the fresh groundwater in Manukan Island was affected by the seawater signature. Values close to ratio of seawater indicate a recent intrusion of seawater into the aquifer. Saturation index values show that the cation exchange process is found to control the concentration of calcium, magnesium, and sodium in the groundwater by precipitation of carbonate minerals as an extended effect from the mixing of seawater and fresh groundwater from its aquifer. The findings show that even though the Manukan Island aquifer is surrounded by seawater and is vulnerable to seawater intrusion attributed to its physical characteristics, it is also heavily affected by human activity related to groundwater abstraction. The data clearly indicate that seawater intrusion is the main contributor to salinity enrichment in the study area.

KRATZMANN, M.G. and HAPKE, C.J., 2012. Quantifying anthropogenically driven morphologic changes on a barrier island: Fire Island National Seashore, New York.

Beach scraping, beach replenishment, and the presence of moderate development have altered the morphology of the dune–beach system at Fire Island National Seashore, located on a barrier island on the south coast of Long Island, New York. Seventeen communities are interspersed with sections of natural, nonmodified land within the park boundary. Beach width, dune elevation change, volume change, and shoreline change were calculated from light detection and ranging (LIDAR), real-time kinematic global positioning system (RTK GPS), and beach profile data sets at two ∼4 km long study sites. Each site contains both modified (developed, replenished, and/or scraped) and nonmodified (natural) areas. The analysis spans 9 years, from 1998 to 2007, which encompasses both scraping and replenishment events at Fire Island. The objectives of this study were to quantify and compare morphological changes in modified and nonmodified zones, and to identify erosional areas within the study sites.

Areas of increased volume and shoreline accretion were observed at both sites and at the western site are consistent with sand replenishment activities. The results indicate that from 1998 to 2007 locations backed by development and that employed beach scraping and/or replenishment as erosion control measures experienced more loss of volume, width, and dune elevation as compared with adjacent nonmodified areas. A detailed analysis of one specific modification, beach scraping, shows distinct morphological differences in scraped areas relative to nonscraped areas of the beach. In general, scraped areas where there is development on the dunes showed decreases in all measured parameters and are more likely to experience overwash during storm events. Furthermore, the rapid mobilization of material from the anthropogenic (scraped) dune results in increased beach accretion downcoast.

National park lands are immediately adjacent to developed areas on Fire Island, and even relatively small human-induced modifications can affect park resources and beach–dune response to storms. This study is the first to conduct a systematic analysis on how anthropogenic modifications affect resources at Fire Island National Seashore and provides essential information for effective management and preservation of coastal resources within the park.

BRAMATO, S.; ORTEGA-SÁNCHEZ, M.; MANS, C., and LOSADA, M.A., 2012. Natural recovery of a mixed sand and gravel beach after a sequence of a short duration storm and moderate sea states.

Using time-averaged images collected by a high-resolution camera, this paper examines the natural recovery of a mixed sand and gravel beach (Carchuna, Spain) after the passing of a westerly storm (significant wave height, H₀ > 3 m; significant wave period, T₀  =  7–9 s; 0.19% occurrence per year; duration 36 h), followed by mild to low-energy (H₀ < 1 m, T₀  =  4–6 s, 33.78%) and moderate-energy (H₀  =  1–3 m, T₀  =  6–9 s, 15.80%) sea conditions. The response of the beach after two storms approaching from the east (0.28%) is also examined. The analysis focuses on one of the beach horn-embayment cells characterized by a bimodal sediment distribution, which is representative of the beach coastline.

The most significant morphological changes occurred after the westerly storm episode and consisted of a shoreline erosion in the order of 5 m/d with a reduction in the beach slope and the cusp horn cross-shore dimension. In conditions of erosion, the sand on the coastline was rapidly transported cross-shore, exposing the underlying gravel sediments which were dragged a short distance seaward to create a longshore bar. The bar subsequently acted as a natural barrier, which helped to protect the beach from further erosion.

During the mild to low-energy and moderate sea states which followed, the beach rapidly recovered and the coastline morphology showed a visible seaward advancement of the horn with an increase in the width of the cross-shore section in comparison to the initial prestorm profile. Through conditions of accumulation, the sand was resuspended and mobilized onshore, creating a layer of sand along the shoreline and rapidly recuperating the beach to its original state.

Morphologic evolution of Carchuna is further investigated through several parameterizations on the forcing condition and in consideration of sediment distribution and beach bathymetry. The results provide insight into the interrelation between the sand and gravel of a mixed beach, showing that bimodal beaches respond differently to commonly accepted empirical sandy-beach relationships.

ISLA, F. I.; QUEZADA, J. F.; MARTÍNEZ, C.; FERNÁNDEZ, A.; and JAQUE, E. 2012. The evolution of the Bío Bío delta and the coastal plains of the Arauco Gulf, Bío Bío region: The Holocene sea-level curve of Chile.

Mid-Holocene highstands are characteristic of the Southern Hemisphere. The Chilean coast extends from 17°S to 56°S in a dominant microtidal regime; thus, it is an ideal place to test ages and altitudes of this highstand with minimal errors. However, coseismic events, the dynamic phenomena they triggered (tsunamis), and the behaviour of land in relation to the overriding of the South American Plate over the oceanic Nazca Plate, make it necessary to distinguish these effects from purely eustatic changes. To the south, the glacioisostatic uplift has been approximately measured. At 37°S, the Coronel coastal plain extends several kilometres inland. Its sediment availability has been related to the supplies of the Bío Bío River. From this beach-ridge plain, shell remains gave a radiocarbon age of 4370 ± 90 years before present (YBP), indicating a highstand not higher than 5 m. Further south, at the Carampangue coastal plain, southern coast of the Arauco Gulf, a radiocarbon age of 8010 ± 90 YBP marks the oldest age of this transgression. Some consequences of the earthquake and tsunami of February 27, 2010, are reported here. The radiocarbon ages of these plains permit completion of a Holocene sea-level curve. These Holocene sea-level data were compared to other regions of South America.

Niveles altos del nivel el mar son característicos del Holoceno medio del Hemisferio Sur. La costa chilena se extiende desde 17 a 56°S en un régimen dominado por micromareas, por lo que resulta ideal para testear con buena precisión edades y alturas de este nivel alto del mar. Sin embargo, episodios cosísmicos, los eventos dinámicos que generan (tsunamis), y el comportamiento del continente en relación a la Placa de Nazca, hacen necesario distinguir estos efectos de los cambios puramente eustáticos. Hacia el sur, el levantamiento glacioisostático ha sido medido aproximadamente. A 37°S, la planicie costera de Coronel se extiende varios kilómetros hacia el interior. Su abundancia de sedimento ha sido relacionada a los aportes del río Bio Bio. De esta planicie de cordones de playa restos de conchilla dieron una edad radiocarbónica de 4370 ± 90 años AP, indicando un nivel alto del mar no mayor de 5 m. Algo más al sur, en la costa sur del Golfo de Arauco, una datación radiocarbónica de 8010 ± 90 años AP está registrando la edad máxima de esta transgresión. Se informan además algunas de las consecuencias del terremoto y tsunami del 27 de febrero de 2010. Las edades radiocarbónicas de estas planicies permiten completar una curva del nivel del mar holocénico. Estos datos del nivel del mar durante el Holoceno fueron comparados con otras regiones de Sudamérica.

HART, A.T.; HILTON, M.J.; WAKES, S.J., and DICKINSON, K.J.M., 2012. The impact of Ammophila arenaria foredune development on downwind aerodynamics and parabolic dune development.

Ammophila arenaria (marram grass) is highly invasive in temperate, southern hemisphere dune systems. Ammophila arenaria is known to form relatively large, uniform foredunes. However, the impact of A. arenaria invasion on adjacent transgressive dune systems is relatively poorly understood. This study (1) documents foredune and parabolic dune development and A. arenaria invasion at Mason Bay, New Zealand and (2) investigates the impact of A. arenaria foredune development on aerodynamic flow patterns and resultant parabolic dune sedimentary dynamics.

Over a period of 40 years, A. arenaria invasion in Mason Bay transformed foredune morphology from an irregular and hummocky morphology to a continuous, densely vegetated foredune complex up to 11 m high. An incipient parabolic dune, initiated from a large blowout, was present prior to A. arenaria invasion. Parabolic dune development occurred through downwind migration of the depositional lobe at an average of 24 m y⁻¹ between 1958 and 1978. Subsequent parabolic development occurred through decreased depositional-lobe migration (0.79 m y⁻¹ between 1989 and 2002) and deflation surface enlargement as A. arenaria increased in extent and density across the dune. Significant vertical accretion and increased stability of the foredune occurred during this period.

Computational fluid dynamics was used to model flow over foredune topographies associated with the native sand binder Desmoschoenus spiralis and the exotic A. arenaria. Ammophila arenaria foredune development has significantly altered the aerodynamic and sedimentary dynamics of the parabolic dune. During onshore SW flows, higher sheltering was modelled in the lee of the A. arenaria foredune with velocities reduced to between 60% and 70% of ambient across the deflation surface. Flow recovery downwind of the A. arenaria high foredune was 81%, compared to 94% for the D. spiralis low foredune with flow influenced up to 40–45 times the A. arenaria foredune height. Reduced flow velocities, increased foredune stability, and stabilisation of the parabolic dune have resulted in a transition from a highly mobile to a highly stable dune.

NORIEGA, R.; SCHLACHER, T.A., and SMEUNINX, B., 2012. Reductions in ghost crab populations reflect urbanization of beaches and dunes.

Coastal management is being challenged to develop and implement measures that safeguard the ecological values of beach and dune ecosystems, particularly in urban settings. Monitoring the efficacy of such interventions requires reliable indicators of ecological change. Here, we tested the efficacy of ghost crabs (Genus Ocypode) to reflect changes in the degree of human beach use and habitat modifications. This was done across six beaches that differed in the degree of “urbanization” on Australia's Gold Coast, which ranks amongst the country's most intensively developed coastal areas. Population densities of crabs closely match the levels of beach use and human disturbance: Beaches with fewer visitors are less likely to be raked mechanically, thereby, supporting significantly higher numbers of crabs than do beaches with more visitors, which are cleaned more frequently. These spatial differences were consistent across eight surveys. Beaches backed by wider dunes that were more densely vegetated were better habitats than were the beaches with severely modified dunes. From a management perspective, our findings emphasize the critical role of maintaining—and possibly restoring—all remnant dune habitats. A premium on conserving dunes should be complemented by continued visitor management and new initiatives to develop and use more ecologically sensitive beach cleaning techniques.

MOHANTY, P.K.; PATRA, S.K.; BRAMHA, S.; SETH, B.; PRADHAN, U.; BEHERA, B.; MISHRA, P., and PANDA, U.S., 2012. Impact of groins on beach morphology: a case study near Gopalpur Port, east coast of India.

Gopalpur Port is being developed as an all-weather open seaport from a fair-weather port which has existed since 1987. Two groins, a 530-m south groin and a 370-m north groin, were constructed during the periods from August 2007 to November 2009 and October 2007 to September 2008, respectively, on the north and south of the 500-m jetty which existed earlier. Port authorities are planning to construct a southern breakwater and a series of seven northern groins. Therefore, it is essential to assess the impacts of coastal structures on beach morphology and shoreline change in the present context and to predict future trends. To achieve this, a long-term observational programme has been conducted since May 2008. Observations include beach profile, shoreline change (berm position), littoral environment observations, and sedimentological characteristics at monthly intervals north and south of the port, covering a total distance of about 5 km. From the analysis of results, erosion is observed north of the northern groin, particularly during the monsoon season. From October to January, deposition is observed mostly in the foreshore which replenishes the erosive environment observed during monsoon. On the other hand, a constant depositional trend is noticed south of the southern groin for 1.5 km. To assess the impacts of the present groins, beach profile and sediment characteristics were compared with observations made from February 2002 to February 2003. The comparison distinctly shows the impact of groins on erosion and deposition on the north and south beaches of the port. Volume, beach width, and beach area estimates indicate that the rate of deposition on the south beach is much faster than the rate of erosion on the north.

ALARI, V. and RAUDSEPP, U., 2012. Simulation of wave damping near coast due to offshore wind farms.

Two hundred wind turbines with an annual productivity of 2.3 TWh, which could produce up to 30% of the energy Estonia needs, are scheduled to be constructed on separate shallows in the NW Estonian coastal waters (the Baltic Sea), 5–20 km off shore. With numerical modeling, we have established a potential impact of the wind farms on wave heights. We concluded that the impact exists in terms of the reduction of significant wave height, but it is very marginal, not more than 1% below 10-m isobaths. This is due to a very small ratio between the turbine diameter and dominant wavelength and the favorable setup of turbines with respect to each other and the coast.

THEENADHAYALAN, G.; KANMANI, T., and BASKARAN, R., 2012. Geomorphology of the Tamil Nadu coastal zone in India: applications of geospatial technology.

The world's coastal environment is made up of a wide variety of landforms manifested by a spectrum of sizes and shapes, ranging from gently sloping beaches to high cliffs. Despite the diversity, coastal landforms are best considered in two broad categories: erosional and depositional. In reality, the overall nature of any coast may be described in terms of one or the other of these categories. An attempt is made in this paper to describe the areal extent of coastal morphology along the entire Tamil Nadu coast, within a 3 km buffer zone. In fact, the Tamil Nadu coast has now become a topic of considerable interest due to the threat of tsunamis and other devastating processes prevailing in this area. Thirty-three geomorphologic features covering an area of 2765 km² and spread over the length of 1117 km were identified and studied spatially and temporally to assess their past and present status. Moreover, the effect of tsunamis on these features was investigated and is discussed in detail. Analysis of the results shows that any one of the relief features present along a given coast is the result of a combination of processes, sediments, and the geology of the coast itself. Beaches, for example, were located only in the central-northern and southern parts of the study area, while the central part is devoid of beaches. Before the last tsunami in 2004, the measurable extent of beaches throughout the study area was increasing due to continuous sedimentation process occurring during 1992–2003. However, the tsunami of 2004 had a major impact on the Tamil Nadu beaches, resulting in their modification. Similarly, other features are treated in this paper.

KETTLE, N.P., 2012. Exposing compounding uncertainties in sea level rise assessments.

Coastal communities and ecosystems, including those along the Carolina coast of the eastern United States, are at risk to permanent or episodic inundation, contamination of freshwater supplies, and a host of other climate change related environmental hazards due to sea level rise. In order to guide development of mitigation and adaptation strategies, stakeholders will require information on baseline conditions and projections of change. However, the interpretation of impact assessments is not always straightforward given the uncertainties in measuring relative sea level rise, the challenges in predicting the magnitude of change, and the difficulty in acquiring appropriate data and methodologies for quantifying impacts. In addition, many sea level rise assessments are not at spatial or temporal scales most relevant for decision makers. In the context of sea level rise assessments, this study presents a model to describe the various sources of compounding uncertainty that can compromise evaluations and complicate interpretations. Sea level trends and impacts along the Carolina coastline—a region at risk to significant economic and environmental losses—are then reviewed as a means of (1) illustrating the compounding sources of uncertainty and (2) testing the state of our knowledge and identifying information gaps and processing limitations that impede understanding adaptation to sea level rise.

KALLOUL, S.; HAMID, W.; MAANAN, M.; ROBIN, M.; SAYOUTY, E. H., and ZOURARAH, B., 2012. Source contributions to heavy metal fluxes into the Loukous estuary (Moroccan Atlantic Coast).

Aluminum, iron, mercury, lead, copper, cadmium, chromium, zinc, manganese, and nickel concentrations were determined in surface and core sediment samples collected in the Loukous estuary (Atlantic Coast, Morocco) to evaluate their levels and spatial distribution. For various metals, the enrichment factor was calculated as a criterion to assess whether their concentrations represented contamination levels or could be considered background levels.

Analytical results were processed using Geographical Information System software to show areas of metal accumulation. Using multivariate statistical analysis, the possibility of distinguishing the sampling stations in relation to their geographical position was evaluated. The radiolead (²¹⁰Pb) and cesium 137 (¹³⁷Cs) profiles in sediment core retrieved from the Loukous estuary were used to study the temporal variations in sedimentation rate and to reconstruct historical trends of heavy metal input and the effects of human activities.

The results show that the distribution of metals in the Loukous estuary is principally influenced by industrial and urban wastes located mostly in the northern coastal area. Marine currents are additional factors influencing metal accumulation in sediments.

OLIVEIRA, A.P.; CABEÇADAS, G., and PILAR-FONSECA, T., 2012. Iberia coastal ocean in the CO₂ sink/source context: Portugal case study.

Carbon fluxes were calculated for the Portuguese western inner continental shelf region (adjacent waters off Douro, Tagus, and Sado estuaries, and Tagus estuary) and the southern outer shelf (Algarve). The role played by the described ecosystems in terms of CO₂ source/sink functioning is compared with other coastal Atlantic systems off the Iberian Peninsula. Overall, the Portuguese western near-shore ecosystems emit 0.3 Tg C yr⁻¹ to the atmosphere, which corresponds to an additional source of approximately 0.1% to the CO₂ emissions of worldwide near-shore ecosystems. In these systems the CO₂ water–air fluxes varied temporal and spatially. From 1999 to 2007, a trend of decreasing fluxes was observed. While annually the Iberia continental shelf is a sink for atmospheric CO₂, roughly at a rate between −2.9 and −0.2 mol C m⁻² yr⁻¹, the Iberia near-shore ecosystems are sources of CO₂ to the atmosphere, displaying fluxes from 0.01 to 76 mol C m⁻² yr⁻¹. An insight into the controlling factors and mechanisms for the CO₂ flux variability for the distinct coastal ecosystem is provided. The Portuguese water–air CO₂ fluxes presented in this work are a contribution to the European CO₂ budgets.

PENTNEY, R.M. and DICKSON, M.E., 2012. Digital grain size analysis of a mixed sand and gravel beach.

A new technique to estimate the properties of sediment from digital images is investigated. Sediment was obtained from mixed sand and gravel beaches in Hawke Bay, New Zealand. Samples were manually sieved, and grain size distributions were compared to those obtained from digital images. Digital image analysis provided variable estimates of the grain size distribution (R²  =  0.21−0.74), with much poorer estimates obtained when images contained grain sizes beyond the range of sediments imaged for the calibration catalogue. A reasonable approximation of the mean grain size of a sample was returned from digital analyses when compared with the mean grain size obtained from sieving (R²  =  0.68), provided all sediment sizes within images fitted within the calibration catalogue. This paper discusses limitations of the technique when applied to mixed sand and gravel beaches, and possibilities for overcoming these (e.g., increasing sampling quantity). It is clear that a deeper understanding of the morphodynamics of mixed sand and gravel beaches requires methods capable of detailing the dynamic fluctuations of grain assemblages. Digital image analysis provides a very promising alternative to laborious and time-consuming manual sieving, and it is hoped that this paper provides a useful additional data set to help in the further refinement of methods for digital image analysis.

PRAVEENA, S.M.; ABDULLAH, M.H.; BIDIN, K., and ARIS, A.Z., 2012. Modeling of water balance components in a small island via a numerical model application.

A numerical model (SEAWAT-2000) was selected to estimate the water balance components in the low-lying area of Manukan Island. The water balance components of the current situation have shown that decreasing freshwater storage is due to irregularities in the patterns of recharge rate and overpumping. Scenarios 1 and 2 were selected for factors that affect the water balance components in the current situation. The water balance components in Scenarios 1 and 2 have illustrated sustainable management and utilization of groundwater resources in the study area. A valuable tool to restore groundwater storage has been demonstrated in Scenario 2, which represents the impact of future El Niño events. The best artificial recharge method must be selected with consideration given to other important factors. Extra meteorological and water usage data will aid sustainable management and utilization of groundwater resources, as well as further reduction of the pumping rate. The results of this study provide a management foundation for restoration of the groundwater resources of Manukan Island. The management foundation can also be used with other small islands that have similar hydrogeological conditions for the purpose of groundwater resource protection.

BACKUS, D.H.; JOHNSON, M.E., and RIOSMENA-RODRÍGUEZ, R., 2012. Distribution, sediment source, and coastal erosion of fan-delta systems on Isla Cerralvo (lower Gulf of California, Mexico).

Located near the tip of the Baja California peninsula, Isla Cerralvo is the sixth largest island in the Gulf of California. Although surrounded by some of the most productive waters in the world, field surveys show that Isla Cerralvo's shelf is largely devoid of biogenic carbonates, especially rhodolith beds, which are found in abundance elsewhere within the region. In counterpoint, a series of prominent fan deltas extend from the mouths of arroyos on Isla Cerralvo, despite the fact that the island has a granitic core, suggesting that the island's bedrock is severely weakened. Field observations suggest that the fracture pattern (submeter), hydrothermal alteration, as well as the orientations of metamorphic foliation, fracture sets, and fault planes all play a role in the accelerated rate of erosion on the island. The role of hydrothermal alteration is illustrated by a principal components analysis of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Short Wave Infrared (SWIR) bands, which links heavily eroded areas at the south end of the island to areas with high concentrations of clays.

A synthetic drainage system created using a 30-m-resolution digital elevation model (DEM) generated from an ASTER image was used to model the Isla Cerralvo drainage basins and stream channel networks. Analyses of basin and stream network information, including basin slope values and channel slope values, were used to identify islandwide differences in basin morphology and erosion characteristics. Stream channel profiles and slope-area data supported by limited uplift data indicate that Isla Cerralvo has not been uplifted as a single block, but it is broken into at least two major structural blocks with different uplift histories.

Due to the arid climate and low annual precipitation, we find that sediment removal from the interior of Isla Cerralvo can only be accomplished by episodic, but very short (hours to days), catastrophic rainfall events caused by hurricanes or chubascos (winter storms). Subsequently, the sediment is eroded from fan deltas and transported southward by longshore currents and wind-generated waves, choking carbonate production along Isla Cerralvo's shore and shelf.

JOHNSON, M.E.; PEREZ, D.M., and BAARLI, B.G., 2012. Rhodolith stranding event on a Pliocene rocky shore from Isla Cerralvo in the lower Gulf of California (Mexico).

Controls on present-day sedimentation around Isla Cerralvo in the southern Gulf of California provide a model for restricted Pliocene limestone distribution. The 10.46-km² island is elongate and roughly parallel to the direction of prevailing north winds. Debris washed from deeply dissected valleys build fan deltas of sand-to-boulder size igneous clasts. These are transported south by long-shore currents, but the fans also create leeward zones with less agitated water. Remnants of a large Pliocene fan are exposed during low tide at Los Carillos on the SE side of the island. Adjacent is an unconformity between granite and granite-derived conglomerate with Nerita scabricosta. This extant gastropod is typical of the high intertidal rocky shore. The conglomerate is capped by a sandstone ramp with Argopecten abietus as an offshore facies. Basalt dikes exhumed from the granite formed natural groins that captured sediments and shells in the sand ramp. Whole rhodoliths, mostly 3.5 cm in diameter and 15-cm deep, covered 150 m² within the ramp, now partly exposed among boulders in the basal conglomerate. Many rhodoliths encrust pea-sized rock cores. Accretion occurred in shallow water protected from extreme agitation by the nearby fan delta. Stranding of rhodoliths on the rocky shore was a storm-induced event.

EMHOFF, K.F.; JOHNSON, M.E.; BACKUS, D.H., and LEDESMA-VÁZQUEZ, J., 2012. Pliocene stratigraphy at Paredones Blancos: Significance of a massive crushed-rhodolith deposit on Isla Cerralvo, Baja California Sur (Mexico).

A white blaze across coastal cliffs is the hallmark of Paredones Blancos on Isla Cerralvo, Mexico. Cliff-forming strata include three roughly 10-m-thick units with a lateral coherence of only 0.75 km. The middle unit is a massive deposit of crushed rhodoliths. The other two units consist of matrix-supported conglomerate with cobbles and boulders of granodiorite, basaltic andesite, and hornblende diorite. By volume, the matrix accounts for >80% of those units, mostly composed of grus from weathered granite. Thin sections were studied from samples collected at five levels through the middle rhodolith unit to determine carbonate purity as a ratio between organic CaCO₃ and inorganic minerals. The bottom and top margins of the deposit show higher levels of mixed clastics, with 37% inorganic mineral content, as compared with 11% toward the middle. Original depositional environments are interpreted as a rhodolith bank adjacent to a large fan delta built seaward from a wide canyon mouth. The stratigraphic sequence records a rise in sea level that brought rhodolith debris to the flooded canyon mouth above the basal conglomerate, and a drop that emplaced another conglomerate above the rhodolith deposit. A Middle Pliocene age is based on co-occurrence of Clypeaster bowersi and Argopecten revellei within the carbonates.

TIERNEY, P.W. and JOHNSON, M.E., 2012. Stabilization role of crustose coralline algae during Late Pleistocene reef development on Isla Cerralvo, Baja California Sur (Mexico).

Crustose coralline algae played a fundamental role in reef establishment during the Late Pleistocene (122,143 ± 175 YBP) on Isla Cerralvo in the southern Gulf of California. Transported cobbles with a generally elongated clast shape (mean sphericity: 0.6) were encrusted by coralline red algae before locking in a N–S alignment (mean N2°W) and providing a fixed substrate for colonization by Porites and Pocillopora corals. A fringing reef grew on this pavement of clast-encrusting rhodoliths and was succeeded by additional cobble-coral cycles. Out of five stratigraphically repetitive cycles, only the second and third offer sufficient exposure to be quantified with any confidence. Census data, cobble orientations, and measurements of algal rinds were collected to characterize the transition from rhodoliths to corals. Clasts in the second cycle (mean dimensions 7.4 × 4.6 cm) have rinds that average 5.4 mm (standard deviation, or SD, 4.2 mm) at their thickest and 0.9 mm (SD 0.8 mm) at their thinnest. Directly overlying corals reflect an average height of 16.2 cm. Clasts within the third cycle (mean dimensions 7.2 × 4.6 cm) have rinds that average 3.1 mm (SD 2.5 mm) at their thickest and 0.9 mm (SD 0.8 mm) at their thinnest. Directly overlying corals reflect an average height of 15.4 cm. Coralline algae helped cement both underlying cobble pavement and reef corals.

RIOSMENA-RODRÍGUEZ, R.; LÓPEZ-CALDERÓN, J.M.; MARIANO-MELÉNDEZ, E.; SÁNCHEZ-RODRÍGUEZ, A., and FERNÁNDEZ-GARCIA, C., 2012. Size and distribution of rhodolith beds in the Loreto Marine Park: their role in coastal processes.

Size, species, growth form, and rhodolith-bed distribution in the Loreto Marine Park were evaluated, based on sampling undertaken in June and December 2009 and 2010. Extensive surveys on nine major beds were performed using global positioning system and scuba methodologies with the goals of determining (1) the size and distribution of rhodolith beds along the central Loreto Marine Park area, (2) the physical structure of the beds, and (3) the species and growth-form composition. We found a total of 732.8 ha of the seafloor covered by rhodolith beds, of which several islands (Coronado and Carmen) and some coastal areas (between Ensenada Blanca and Puerto Escondido) represented the most extensive accumulations. Most of the studied beds were composed by living material, but in the bed located off the south end of Carmen Island a ratio of 50∶50 living-to-dead rhodoliths was discovered. Three species were found commonly to compose the beds (Lithophyllum margaritae, Neogoniolithon trichotomum, and Lithothamnion muellerii), whereas only two growth forms were present (fruticose and incrusting) dominating the beds. Branch density, rhodolith density, and sphericity were found to be similar in all sampling areas. This suggests that the various beds are related to main currents within the park. However, incrusting growth forms and densely branched fruticose plants were only present in the bed from the Danzante area. This suggests that the presence of a rocky bottom is relevant to the composition of growth forms. Results of this study strongly suggest that rhodolith beds contribute to coastal processes by constantly producing sand derived from broken material. In addition, the extensive cover by rhodoliths is significantly high for the shallow areas surveyed. Future surveys into deeper waters and other areas to more fully understand the role of rhodoliths and their taphonomy in coastal areas are needed.

PEREIRA-FILHO, G.H.; AMADO-FILHO, G.M.; MOURA, R.L.; BASTOS, A.C.; GUIMARÃES, S.M.P.B.; SALGADO, L.T.; FRANCINI-FILHO, R.B.; BAHIA, R.G.; ABRANTES, D.P.; GUTH, A.Z., and BRASILEIRO, P.S., 2012. Extensive rhodolith beds cover the summits of southwestern Atlantic Ocean seamounts.

Calcium carbonate production by marine organisms is an essential process in the global budget of , and coralline reefs are the most important benthic carbonate producers. Crustose coralline algae (CCA) are well recognized as the most important carbonate builders in the tropical Brazilian continental shelf, forming structural reefs and extensive rhodolith beds. However, the distribution of CCA beds, as well as their role in mineralization in mesophotic communities and isolated carbonate banks, is still poorly known. To characterize the bottom features of several seamount summits in the Southwestern Atlantic (SWA), side-scan sonar records, remotely operated vehicle imagery, and benthic samples with mixed-gas scuba diving were acquired during two recent research cruises (March 2009 and February 2011). The tops of several seamounts within this region are relatively shallow (∼60 m), flat, and dominated by rhodolith beds (Vitória, Almirante Saldanha, Davis, and Jaseur seamounts, as well as the Trindade Island shelf). On the basis of abundance, dimensions, vitality, and growth rates of CCA nodules, a mean CaCO₃ production was estimated, ranging from 0.4 to 1.8 kg m⁻² y⁻¹, with a total production reaching 1.5 × 10⁻³ Gt y⁻¹. Our results indicate that these SWA seamount summits provide extensive areas of shallow reef area and represent 0.3% of the world's carbonate banks. The importance of this habitat has been highly neglected, and immediate management needs must be fulfilled in the short term to ensure long-term persistence of the ecosystem services provided by these offshore carbonate realms.

DIAS, G.T.M., and VILLAÇA, R.C., 2012. Coralline algae depositional environments on the Brazilian central–south-eastern shelf.

The Brazilian central shelf along the State of Espirito Santo features several palaeochannels eroded into deposits of coralline algae. Seismic profiles and jet-probe cores have shown a layer of calcareous sediments over 10 m thick that is formed mainly by the fragmentation of coralline algae. Video and scuba-diving observations demonstrate that dense aggregations of rhodoliths often change position on the sea bottom as a result of being dragged (“sail” effect) by foliose algae such as Sargassum, Dictyopteris, and Zonaria. The benthic fauna associated with rhodoliths or foliose macroalgae (Hydrozoa and Amphipoda) is dominated by polychaetes, ophiuroids, and molluscs. The sessile fauna is poorly represented, consisting of some sponge species. It was possible to verify the following dynamics: (i) in summer, foliose macroalgae and zoobenthos (phytal) are established upon the rhodoliths; (ii) in early and midwinter, epiphytic macroalgae are senescent; (iii) in late winter, storms disturb sediments on the sea bottom, burying living rhodoliths and removing the foliose algae; and (iv) in spring, a bloom of the bivalvia Pinctata pectinata occurs, overgrowing the bottom. The rhodoliths tend to remain on the seafloor (with 10% to 20% estimated buried and becoming permanently incorporated to the sediment mass). The sediment dynamics are strongly dominated by erosive phases related to storms.

MEIHOUB BERLANDI, R.; FIGUEIREDO, M.A.O., and PAIVA, P.C., 2012. Rhodolith morphology and the diversity of polychaetes off the southeastern Brazilian coast.

Rhodoliths modify the physical characteristics of their environment, producing a habitat that can support diverse, associated fauna, where polychaetes often achieve high richness expressed in density and trophic diversity. Nevertheless, there are few studies that describe and identify the fauna associated with this habitat. In this research, specimens were collected from 6 to 18 m depth in Brazilian rhodolith beds: two off the southern coast of Espírito Santo, Brazil, and one in the Abrolhos bank, Brazil. The most common rhodoliths were Lithophyllum corallinae, Neogoniolithon sp., and Mesophylum erubescens. The rhodoliths ranged from large with short branches to small with long branches. Polychaetes at Espírito Santo, Brazil were predominately infaunal, whereas in Bahia, Brazil, they were mainly epifaunal living among finely branched structure. Twenty-six families were identified, four exclusive to Espírito Santo, Brazil, and nine in the Abrolhos, Brazil. The most common families registered different species composition in both rhodolith beds, except for Eunice multicylindris and Arabella mutans found in both regions. Syllidae was the most abundant and species-rich family in Abrolhos, Brazil. Rhodoliths off Espírito Santo, Brazil, hosted polychaetes dominated by burrowers, such as the Lumbrineridae, which were favored by their boxwork structure, built of invertebrates and inorganic material. Rhodoliths on the Abrolhos, Brazil, hosted polychaetes dominated by carnivorous or herbivores families, such as the Syllidae. There is a significant difference between Espírito Santo, Brazil, and the Abrolhos, as reflected by the polychaete taxocoenosis. This is demonstrated by a clear differentiation in species and family composition and also by feeding guilds, indicating how different rhodolith morphologies can affect community structure.

BASSI, D.; IRYU, Y., and NEBELSICK, J.H., 2012. To be or not to be a fossil rhodolith? Analytical methods for studying fossil rhodolith deposits.

The past environment is often reconstructed by measuring certain proxy data, such as changes in oxygen isotopes, taxonomic assemblages, and taphonomic signatures in a palaeoenvironmental archive (e.g., rhodoliths, corals, invertebrate shells, trees, ice cores, speleothems, etc.). Proxy analysis usually yields a record that has to be compared with present-day analogues to yield meaningful results. This also holds true for the interpretation of the palaeoenvironment of rhodolith deposits. The characteristics of Recent rhodoliths and the environments in which they are formed, thus, need to be known to interpret their fossil counterparts. The comparison of fossil and Recent rhodoliths and their environment is, however, not straightforward because the respective analytical methods applied to them are usually different and often difficult to reconcile. To reduce the uncertainties of this problem and to facilitate direct comparisons, we describe a number of analytical methods applied to fossil rhodoliths that can also be performed on Recent material. The analytical methods introduced here correspond to three different scales of analysis: (1) the outcrop scale as completed in field studies and the study of (2) isolated specimens and (3) thin sections in the laboratory.

BAARLI, B.G.; SANTOS, A.; DA SILVA, C.M.; LEDESMA-VÁZQUEZ, J.; MAYORAL, E.; CACHÃO, M., and JOHNSON, M.E., 2012. Diverse macroids and rhodoliths from the Upper Pleistocene of Baja California Sur, Mexico.

Small multitaxonomical nodules, characterized as rhodoliths, balanuliths, coralliths, bryoliths, and nodules composed of vermetids “vermetuliths,” are described from one horizon in carbonate sand from the Upper Pleistocene Mulegé Formation at Playa La Palmita, Baja California Sur, Mexico. Such a diversity of fossil, free-rolling biota is seldom described in the literature. This is the first time vermetuliths are reported in the fossil record; in addition, the coral Astrangia has not been reported to constitute coralliths before. These nodules and their associated firm-ground were generated in a shallow bay near rocky shores. Break up of a firm-ground during a sedimentary hiatus provided fragments of loosely consolidated, carbonate sandstone for organic nucleation. Fast growers, like balanids, vermetids, and bryozoans, settled on these sandstone fragments or on bioclasts. Initial rapid growth of pioneer organisms was succeeded by a period of bioerosion, and finally, encrustation with a thin, crustose to lumpy cover of coralline red algae in the climax stage of succession. These were insipient rhodoliths, where the thin cover of coralline red algae reflects a short residence time. Also evident is a rich crypto- and endofauna that lived within and an epifauna that lived on the nodules.

LEAL, R.N.; BASSI, D.; POSENATO, R., and AMADO-FILHO, G.M., 2012. Tomographic analysis for bioerosion signatures in shallow-water rhodoliths from the Abrolhos Bank, Brazil.

Bioerosion at all scales is now recognized as playing a major role in facies interpretation. Macroscopic and microscopic borings can provide an indication of water depth, if they can be attributed to the action of specific borers. Tomographic analysis is a new method for assessing bioerosion, for identifying boring taxa, as well as for calculating the volume and porosity in present-day rhodoliths. The tomographic system provides also a quantification of the calcium carbonate produced by bioerosion. Recent rhodoliths collected at 20-m water depth on the Abrolhos Bank, Brazil, have been multiscann analyzed. The study shows that rhodoliths from this site are characterized by a highly diversified assemblage of boring bivalves and sponges associated producing the ichnogenera Gastrochaenolites and Entobia. The fauna from this boring assemblage can remove up to 10% of the rhodolith volume. The method can be expected to yield similar results as applied to both modern and fossil rhodoliths from other localities and time frames.