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Cabral, A.P. and Noernberg, M.A., 2024. Morphological characteristics of an open shelf ridge at Rio Grande do Norte continental shelf, NE Brazil. Journal of Coastal Research, 40(6), 1166–1181. Charlotte (North Carolina), ISSN 0749-0208. This paper describes for the first time the occurrence of an open shelf ridge (OSR) in the South Atlantic Ocean, evidencing morphological differences with respect to occurrences in other regions. The unique configuration of this OSR derives from the characteristics of the shallow continental shelf frontal to the Calcanhar Cape, Rio Grande do Norte State, Brazil, where it is located. It is a shallow, narrow, stepped shelf with an escarpment corresponding to a drowned shoreline around the 35 m isobath. There are extensive siliciclastic and carbonate sand deposits, sand ribbons, subaqueous dune fields, coral reefs, and calcareous algae patches. The high transparency of the water allows the use of multitemporal optical satellite images from remote sensors in the bathymetric modeling and morphodynamic description, in conjunction with echo sounder surveys, in situ sampling, and modeling. The metocean conditions of the region were determined from current and wind data obtained in situ, as well as data from the Hybrid Coordinate Ocean Model (HYCOM) and Regional Ocean Modeling System (ROMS) numerical models. Combining these data allowed the identification, characterization, and analysis of the metocean patterns over the OSR. Superimposed onto the OSR, there is a field of asymmetric subaqueous dunes transverse to the ridge axis with wavelengths between 150 m and 2 km and heights between 2.5 m and 9 m, with a tendency for sediment transport offshore northwestward of the OSR crest. The synergistic effect of the dominant NE winds and the North Brazil Current with tidal currents drives the main metocean forcings. The hydrodynamic pattern for the main sedimentary deposit areas is described, and the effect of the OSR on general subaqueous dune field configuration is presented. [ABSTRACT FROM AUTHOR]

Fuentes-Agueda, S.A.; Gallegos, M.E.; Mandujano, M.C., and Golubov, J., 2023. Contrasting growth and establishment of Thalassia testudinum along a cover gradient in the Gulf of Mexico. Journal of Coastal Research, 39(4), 653–662. Charlotte (North Carolina), ISSN 0749-0208. Seagrasses are important for coastal ecosystem health and have significant economic benefits; however, they are undergoing important negative changes worldwide. The seagrass Thalassia testudinum comprises one of the main elements in submerged aquatic vegetation (SAV) habitats, and it grows in monospecific and mixed meadows along the continental shelf of the Gulf of Mexico. In this study, T. testudinum monospecific and mixed meadows were monitored over a 2 year period to identify the abiotic and biotic conditions that may correlate with population parameters through the plastochron index (PI). Plants found in monospecific meadows had larger rhizomes and more flowers in comparison to those in mixed meadows, while the latter produced more leaves and larger shoots. The annual rate of change in biomass (Br) of T. testudinum in the monospecific meadow was 1.15 ± 0.03, which was slightly higher than that in the mixed meadow, with a value of 1.12 ± 0.03. T. testudinum in monospecific meadows tended to exhibit increased sexual reproduction, while vegetative growth and clonal reproduction were more common in mixed meadows. The results highlight that T. testudinum life-history strategies and establishment are affected by both biotic and abiotic factors like depth, temperature, and water nutrients. [ABSTRACT FROM AUTHOR]

Alfredini, P.; Martins, L.F.; Neves, R.C.; Martinez, F.A., and Arasaki, E., 2024. Statistical assessment of extreme storm events on the Brazilian Continental Shelf from 1940 to 2022. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 175-179. Charlotte (North Carolina), ISSN 0749-0208. The Brazilian Continental Shelf is the largest in Latin America and the South Atlantic Ocean, covering more than 8,500 km and stretching from Latitude S 34° to Latitude N 6°. The Rio de La Plata Delta discharges sediment over a wide area in the southern portion of this shelf. Submerged peaks of the Vitória-Trindade Chain have an influence on an intermediate region of the shelf. Northward, the Continental Shelf becomes thinner, until reaching its maximum width in the Maranhão Gulf and Amazon Mouth. In addition to the different wave climates along the Brazilian coast, around 55% of the country's population lives in the coastal region, with large population concentrations in metropolitan regions, such as Rio de Janeiro, Salvador, Recife and Fortaleza. The oil and gas industry has many offshore structures on the Continental Shelf, and the cargo throughput from ports reached 1.217 billion tons in 2023. Therefore, any change in meteo-oceanographic patterns in Brazilian Continental Shelf can have major impacts because maritime infrastructures and operations tend to be progressively affected by the increasing frequency and intensity of extreme meteorological phenomena due to climate change. Impacts like coastal erosion, augmented occurrence of storms and flooding can damage essential infrastructure in cities, ports, and other coastal and offshore scenarios. Therefore, understanding these changes is necessary for planning and executing actions to mitigate and adapt. The objective of this paper is to make a statistical assessment of a first approach to identify trends that may point changes in the extreme events of storm over the period from 1940 to 2022, assessing time series of wave data from the European Centre for Medium-Range Weather Forecasts ERA 5 Oceanographic Model, in twelve locations of Brazilian Continental Shelf, from the extreme south to the extreme north. The storm events were identified by the peak over threshold method and the statistical assessment employed moving averages for 5 years and was possible to identify an increasing frequency and severity of storm per year from 1980 in the south and a smaller increase in the northern area. [ABSTRACT FROM AUTHOR]

Long, J.H.; Hanebuth, T.J.J.; Alexander, C.R., and Wehmiller, J.F., 2021. Depositional environments and stratigraphy of Quaternary paleochannel systems offshore of the Georgia Bight, southeastern U.S.A. Journal of Coastal Research, 37(5), 883–905. Coconut Creek (Florida), ISSN 0749-0208. Paleochannels are common subsurface geological features beneath inner continental shelves and coastal plains and are important archives of ancient depositional environments. This study, focusing on a 450-km portion of the inner continental shelf of the SE United States, adds to understanding of the timing of paleochannel development, the paleoenvironments in which they formed, and the mechanisms that drove their formation. Integrated analysis of 1089 km of high-resolution seismic reflection data and 12 sediment cores reveals that (1) most paleochannels documented here formed in backbarrier environments (estuarine or lagoonal) and were subsequently filled during transgression or following avulsion, preserving mud-rich, tidally influenced deposits; (2) the preservation of nonmarine deposits is rare; (3) paleochannels are either solitary or amalgamated, forming paleochannel complexes within which they are arranged in multistory (vertically stacked) or multilateral (horizontally offset) configurations, a product of local hydrodynamic conditions, antecedent geology, glacioeustatic cycles, and regional isostatic adjustments; and (4) a general southerly increase in the overall degree of channelization is observed across the Georgia Bight, a function of long-term accommodation, interaction with underlying stratigraphy, and dominant coastal processes. The composition and spatiotemporal distribution of paleochannel systems has implications for understanding the long-term evolution and preservation of complex coastal systems and informing regional Quaternary sea-level reconstructions. [ABSTRACT FROM AUTHOR]

Pickens, B.A.; Taylor, J.C.; Finkbeiner, M.; Hansen, D., and Turner, L., 2021. Modeling sand shoals on the U.S. Atlantic shelf: Moving beyond a site-by-site approach. Journal of Coastal Research, 37(2), 227–237. Coconut Creek (Florida), ISSN 0749-0208. The demand for offshore marine sands has escalated worldwide as sediments are needed for increasingly frequent beach renourishment and barrier island restoration. Sand shoals are often used as a source for dredging material because of the high volume of sand per unit area. Yet, investigations of shoals are typically conducted on a site-by-site basis, and a broader understanding of shoal availability is needed for strategic decision-making, including the mitigation of ocean use conflicts. Here, the primary objective was to model shoal distribution across the U.S. Atlantic shelf, including the Gulf of Mexico. Publicly available bathymetry data were obtained at a relatively coarse 90-m resolution. Variables of depth, standard deviation of depth, slope, bathymetric position index, and distance to shoreline were used as predictors to identify shoals. Unsupervised classifications of the seafloor were conducted to distinguish shoals and swales. Classification accuracy was assessed with validation databases of identified sand resources and named shoals compared to random locations; a visual assessment was also conducted. Shoals were further characterized by their origin. The classifications showed shoals and swales differed from the seafloor. Shoals were more shallow, had higher slope, a higher standard deviation of depth, were closer to the shoreline, and had a more positive bathymetric position index. Shoals were classified on 4.7% of the U.S. Atlantic shelf, and validation showed a percent agreement of 65–93%. Classified shoals visually coincided with the shape and extent of known sand resources. Shoals were characterized as cape-associated, bedform, isolated shelf, or uncharacterized. For the continental shelf, multivariate predictors represented the heterogeneous sloping substrates and the flat, high relief crests of sand shoals. The ability to classify shoals with 90-m resolution bathymetry data in the U.S. Atlantic reveals the methodology may be applicable to identify sand shoals elsewhere in the world with currently available data. [ABSTRACT FROM AUTHOR]

de Souza, C.S.; da Conceição, L.R.; Freitas, T.S.S.; Aboim, I.L.; Schwamborn, R.; Neumann-Leitão, S., and Mafalda, P.d.O., Jr., 2020. Size spectra modeling of mesozooplankton over a tropical continental shelf. Journal of Coastal Research, 36(4), 795–804. Coconut Creek (Florida), ISSN 0749-0208. Size spectra analysis is a useful way of studying biomass and energy flow in ecosystems across trophic levels. The size spectrum reflects a balance of energy and matter between gains through growth and recruitment and losses though mortality in a size-structured community. Therefore, changes in biomass and normalized biomass size spectrum (NBSS) slope and intercept between time or environment can be used to assess the energy transfer efficiency within ecosystems. Linear models were developed to analyze zooplankton biomass and community size structure for the narrow continental shelf and shelf break off Salvador, Brazil, using samples that were collected during 10 oceanographic cruises, from April 2013 to October 2014, and analyzed with a ZooScan. Three descriptors of zooplankton size spectra were examined: size diversity, NBSS slope, and intercept. Copepods were always dominant in abundance. Size spectra varied considerably along a short coast-to-offshore transect of 17 km. The pattern of spatial change presented a predominance of larger size fractions nearshore (flat NBSS slope, –0.56) and the predominance of smaller sized organisms in oceanic waters (steep NBSS slope, –0.88). This gradient was mostly due to the higher abundance of large (>5 mm equivalent spherical diameter) gelatinous organisms (mainly hydromedusae) nearshore. The results suggest that the tropical zooplankton community at the continental shelf off Salvador was characterized by low productivity and low trophic efficiency, especially offshore. Although copepods were dominant in numbers, large-sized gelatinous predators were the key structuring zooplankton taxon in this area. [ABSTRACT FROM AUTHOR]

Mattheus, C.R.; Ramsey, K.W., and Santoro, J.A., 2020. Evaluating continental shelf seabed-elevation changes from archived sediment-core records: Issues with vertical positioning and implications for integration with subsurface geophysics. Journal of Coastal Research, 36(1), 41–53. Coconut Creek (Florida), ISSN 0749-0208. Sediment-core records from the sand ridge–dominated inner continental shelf of Delaware were studied to address impacts of seabed morphodynamics and positioning accuracy on data integration. Differences in vertical seafloor position were calculated for 366 point locations from core-report information (from 1984 to 2017) and a 2007 echo-sounding data set. Resulting net-change metrics were evaluated against seafloor geology and shelf zonation based on morphology. While gravelly units trended slightly towards net-elevation loss at an average of –0.2 m, shoal sand bodies averaged net-zero change. Almost 90% of change metrics fell within ±2 m, approximating the average relief of major shelf bed forms. A pairwise analysis of variance test revealed no statistically significant difference in vertical change at the 0.05 confidence level, based on geology, nor based on shelf zonation. Vertical positioning inaccuracies and reporting issues are primary concerns, even after quality control eliminated over 20% of available core records (total n = 466) because of undocumented tidal correction and vertical datum conversion procedures, which could have resulted in vertical offsets on the order of 2 m. Within the remaining data set, questionable values were recognized by a GIS-based buffer analysis, using core age and an assumed 10 m/y rate of bed-form migration to isolate metrics in disagreement with seafloor morphology. Data from three coring projects consistently overvalued net-change predictions, raising questions about their utility as stratigraphic benchmarks for ground-truthing seismic data. Accurate constraint of core depth is crucial for offshore resource allocation and infrastructure planning efforts, highlighting the importance of investigating vertical data resolution and addressing reporting inaccuracies. [ABSTRACT FROM AUTHOR]

Sediment mobilization, especially from offshore bay to the coast during the Holocene, along the inner continental shelf of Bay of Biscay is less understood. Acoustic and sediment sampling and surveys were conducted offshore of the Bay of Étel to define the shallow geologic framework and the sedimentology. Results of these campaigns are used to identify and map Holocene deposits, discuss sediment transport pathways and depth of closure using Hallermeier's approach in order to define the active sedimentary prism using the depth of closure on a meso-tidal and wave dominated coast. In the Bay of Étel, Holocene sediments are concentrated between rocky shoals and emerged rocks, passing from external zone by sand lobe, 20 m thick to the medium zone, 15 m thick, to the beaches of the Gâvres-Penthièvre beach dune system (modern coastal prism). This case study found that the thickest deposits of Quaternary sediments observed along the inner shelf have a strong dependence on coastal topography and structural heritage. The presence of offshore basement shoal has been determined to have exercised control over sediment transfers from offshore to landward regions during the last marine inundation. Due to the lack of any significant modern fluvial input of sand in the region, the Holocene deposits are inferred to have been derived by reworking of relict Pleistocene and older inner-shelf deposits. Sediment textural trends and seafloor morphology from the medium zone to the beach dune system indicate an absence of relationships (linking) between the modern sedimentary prism and the potential source of sediment to the shoreline. [ABSTRACT FROM AUTHOR]

Carassai, J.J.; Lavina, E.L.C; Chemale, F., Jr., and Girelli, T.J., 2019. Provenance of heavy minerals for the Quaternary coastal plain of southernmost Brazil (Rio Grande do Sul State). Journal of Coastal Research, 35(2), 295–304. Coconut Creek (Florida), ISSN 0749-0208. During the Quaternary, an extensive barrier system was developed in southern Brazil and northern Uruguay. The patterns of variation in the distribution and behavior of heavy minerals present in the aeolian and marine (upper shoreface-foreshore) facies of the four barriers formed in the Rio Grande do Sul costal plain were identified. Minerals were analyzed by scanning electron microscopy, including epidote, tourmaline, zircon, magnetite/ilmenite, polymorphs of aluminum silicates (andalusite, kyanite, and sillimanite), staurolite, rutile, amphibole, pyroxene, corundum, perovskite, chromite, garnet, apatite, monazite, xenotime, spinel, and titanite. In all of the barriers, zircon, magnetite, and ilmenite are the most important, followed by chromite, garnet, rutile, tourmaline, staurolite, and epidote. In total, heavy minerals indicate two primary sources in the coastal plain: (a) direct feeding from the rocks of Uruguay and Rio Grande do Sul Shield and Paraná Basin, drained by Rio Camaquã and Rio Jacuí; and (b) indirect feeding from rocks of the Andean province, drained by Rio Paraná and Rio La Plata estuary in northern Argentina. During low sea level, rivers flowed directly into the continental shelf, and their deposits were reworked during subsequent transgressive stages. Throughout this region, the atmospheric circulation pattern forms a NW oceanic swell, generating a longshore current with dominant northward direction. Thus, several transgressive-recessive pulses associated with Pleistocene glacial events pushed large volumes of sediments northward, giving rise to the present southern Brazil coastal plain. [ABSTRACT FROM AUTHOR]

Vassie, J. and Choi, B.H., 2018. Simulation of Normandy Invasion on 6th of June, 1944. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1071–1075. Coconut Creek (Florida), ISSN 0749-0208. Known as one of the greatest military secrets of "Operation Overlord," the cross- English Channel invasion of the northern coast of France on June 6, 1944, called for the Allies with accurate wave and tidal forecast for landing operation. Times of small wave and low tide were essential for successful landing. We are revisiting forecasts (hindcast simulation) via modern day updated numerical modeling based on coupled tide-wave-storm surge physics. The wind conditions are reproduced by using the meteorological conditions from ECMWF ERA-20C data of assimilation group. An integrally coupled tide-surge-wave model based on the identical, homogeneous and unstructured meshes were used for correct resolving the physics of tide-wave-surge interaction and performing for each transect, perpendicular to the beach, respectively. The model domain covers the wide Northwest European continental shelf and fine meshes with about 20m resolution in the Normandy invasion beaches. We performed the real time tidal simulation and compared with Kelvin (Doodson-Lege) tidal prediction. The tidal and wave prediction time sequential results are posted in the website, https://sites.google.com/site/bhchoiskku/dday, near the landing time, 6th of June 6:30 AM. [ABSTRACT FROM AUTHOR]

Jardim, K.A.; Santos, V.F., and Oliveira, U.R., 2018. Paleodrainage systems and connections to the southern lacustrine belt applying remote sensing data, Amazon coast, Brazil. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 671–675. Coconut Creek (Florida), ISSN 0749-0208. Paleodrainage systems mapped in many regions worldwide reveal important inactive fluvial systems that indicate changes in morphosedimentary, tectonic and environmental processes in different time scales. Two paleodrainage systems were identified north of the Amazon River mouth, associated with the Southern Lacustrine Belt at Cabo Norte. The analyses were performed using data from orbital remote sensors, validated by field information and overflights. The paleodrainage systems show predominant North-South (N-S) and Southwest-Northeast (SW-NE) directions. The N-S system may be connected to an ancient Pleistocene coastline. The SW-NE system is younger, with the same direction as the current river courses and is associated with the genesis of the Araguari River. The paleodrainage alignments of this system in the Northwest-Southeast direction (NW-SE) show the same direction as tectonic lineaments presented from the basement to the continental shelf. The identified paleodrainage systems indicate significant changes in the regional drainage of the Amazonian coastal plain and indicate intense riverbed aggradation processes, which may be associated with neotectonic movements and relative sea level variations during the Quaternary. These are important indicators for the understanding of environmental changes during the Late Pleistocene and Holocene, and may aid in the paleogeographic reconstitution of the Amazon river mouth. [ABSTRACT FROM AUTHOR]

Seo, J.; Ku, H.; Cho, K.; Maeng, J.H., and Lee, H., 2018. Application of SLOSH in estimation of Typhoon-induced Storm Surges in the Coastal Region of South Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 551–555. Coconut Creek (Florida), ISSN 0749-0208. SLOSH (Sea, Lake, and Overland Surges from Hurricane) is a dynamic tropical surge model forecasting real-time storm surges by solving two-dimensional Navier-Stokes equations with hydrostatic approximation. To apply this model SLOSH on estimating the typhoon-induced storm surges around Korean coastal regions, a two-dimensional hyperbolic domain covering the East, the West and the Southern Seas of Korea is developed. The grid resolution is as high as approximately 500m at the coast and extended to about 4.2km far away ocean. By adopting 30-m digital elevation map SKKU DEM which has an advantage on connectivity between land and ocean and KorBathy30s which is 30 seconds gridded bathymetry of Korea marginal seas, the local characteristics are considered on the shape of continental shelf of the East Sea, the West Sea, and the Southern Sea. This SLOSH input domain for Korea is examined by applying for three strong, historical typhoons, THELMA(1987), FAYE(1995), RUSA(2002), MAEMI(2003), MEGI(2004) and SANBA(2012) and comparing to observational storm surges at two tidal station located in southern coastal cities of Tongyeong and Yeosu, South Korea. The SLOSH reproduced well the typhoon-induced surge pattern which dramatically increased and suddenly drop as the typhoons are passing through the stations. In case of typhoon MAMEMI(2003) which recorded almost 170cm of typhoon-induced surge height, the model SLOSH estimates it with less 1% error. At this station, the root-mean-square is shown as 27.92. [ABSTRACT FROM AUTHOR]

Otosaka, S.; Hou, Y.; Wakita, M.; Yamashita, Y.; Nishioka, J.; Obata, H.; Miyairi, Y.; Yokoyama, Y., and Ogawa, H., 2023. Origin and transport of dissolved organic matter in the northwestern margin of the North Pacific inferred from radiocarbon signatures. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 181-185. Charlotte (North Carolina), ISSN 0749-0208. Distribution of Δ14C (an index of radiocarbon concentration/radiocarbon dating) in Dissolved Organic Carbon (DOC) was observed at four stations, one in the subarctic gyre and three in northwest marginal regions of the western North Pacific, to track the dynamics of organic matter. At all stations, Δ14C in DOC was explained by a two-component mixing model of "fresh" DOC produced in the surface layers and "old" DOC circulating in the deep layers. In the subarctic gyre, the estimated concentration of old DOC was the highest in the intermediate layer (200–800m). On the other hand, in the marginal regions, the concentrations of old DOC were particularly high in the upper layers of the connection region with the marginal sea. These results suggest that allochthonous dissolved organic matter from the marginal region was transported to the open ocean through the intermediate layer. The transport processes of dissolved organic matter inferred in this study provide an important basis for explaining the relationship between dissolved organic matter exports from land, coasts, and the continental shelf and biological production in the northwestern North Pacific. [ABSTRACT FROM AUTHOR]

Delgado, A.L.; Menéndez, M.C.; Piccolo, M.C., and Perillo, G.M.E., 2017. Hydrography of the inner continental shelf along the southwest Buenos Aires Province, Argentina: Influence of an estuarine plume on coastal waters. Estuarine plumes have a significant influence on the characteristics and biology of the adjacent inner shelf. In the sector occupied by the plume, several transformations occur to the sediment and nutrients exported from the continent to the oceans. The coastal zone of Pehuén Co (PC) and Monte Hermoso (MH) is located in a highly complex oceanographic and ecological regional system, which creates the basis of one of the most valuable Argentinean habitats for fishing of commercial species. In this work, the physical oceanographic characteristics of the inner shelf of the southwest Buenos Aires Province and the influence of the Bahia Blanca estuarine (BBE) waters are introduced. The in situ data obtained from oceanographic cruises included vertical profiles of water temperature, salinity, and turbidity. The spatial variability of the parameters was studied with a multivariate statistical analysis. Temperature and salinity presented high seasonal variability (6.1-22.9°C; 33.5-36, respectively). Maximum turbidity occurred throughout the summer (64 nephelometric turbidity units [NTU]) and showed a minimum during spring (24 NTU). The study area was characterized by a significant spatial variability, especially in terms of salinity and turbidity, while water temperature showed a more homogeneous pattern. Salinity and turbidity values decreased from PC (closer to BBE) to MH (further from BBE) stations, with the highest values located near the mouth of the BBE. The PC and MH (to a lesser extent) inner shelves are transitional environments between the estuary and the open beaches of Buenos Aires Province, creating a habitat where benthic and zooplankton estuarine and marine species are found. [ABSTRACT FROM AUTHOR]

Makowski, C.; Finkl, C.W., and Vollmer, H.M., 2017. Geoform and landform classification of continental shelves using geospatially integrated IKONOS satellite imagery. Geomorphological characterization of coastal environments along continental shelves depends on accurate interpretation of mesoscale lithic and clastic benthic geoforms and landforms. Using the Geospatially Integrated Seafloor Classification Scheme (G-ISCS), cognitive visual interpretations of seafloor geoforms and their associated landforms were conducted along a diverse segment of the southeast (SE) Florida continental shelf. GeoEye IKONOS-2 satellite imagery provided the remotely sensed visual medium on which interpretations were based. With ESRI ArcGIS® ArcMap software, classification maps were created from the cognitive interpretations to show spatial distribution results of geoform and landform features throughout the study area. Additionally, smaller-scale 'call-out figures' documented specific geomorphological associations among the classified units. Analysis attribute tables compared and contrasted the abundance ( i.e. number of classifying vector polygons) and calculated areas for each geoform and landform classified. It was determined that classification of geoform and landform benthic features along continental shelves can be achieved where water clarity conditions allow for the cognitive visual interpretation of such seafloor formations. Future studies may build upon the classification of continental shelf geoforms and landforms to integrate more transient biogeomorphological features of the marine environment ( e.g., sediment distribution, biological species identification, density of flora and fauna present), thus creating a more detailed and inclusive classification of a selected coastal region. [ABSTRACT FROM AUTHOR]

Otsuka, A.Y.; Feitosa, F.A.N.; Flores-Montes, M.J., and Silva, A., 2016. Dynamics of chlorophyll a and oceanographic parameters in the coastal zone: Barra das Jangadas-Pernambuco, Brazil. The Pernambuco shelf, inserted into the NE-E continental margin of Brazil, is about 187 km long and is characterized by reduced width, shallow depth, gentle slope, relatively warm water, and high salinity. It is influenced to some extent by translittoral rivers, the Jaboatão River being among these. This study aimed to analyze the dynamics of chlorophyll a and hydrological parameters on the Pernambuco inner continental shelf under the influence of the Jaboatão River plume. Bimonthly samplings were carried out during the rainy and dry seasons at one point in the estuarine area and four points along the adjacent inner continental shelf. The parameters evaluated were chlorophyll a, temperature, salinity, transparency, dissolved oxygen, suspended particulate matter, pH, depth, and inorganic nutrients. Most parameters had significant seasonal variation. In the dry period, chlorophyll- a ranged from 2.89 to 34.71 mg m−3 in the estuary and varied from 0.21 to 9.67 mg m−3 on the shelf. In the rainy period, it varied from 0.79 to 12.46 mg m−3 in the estuary and from 0.26 to 4.59 mg m−3 on the shelf. According to a principal components analysis, chlorophyll a showed a direct relationship with oxygen saturation rate and temperature and an inverse relationship with pH, salinity, and water transparency. Two points on the shelf (points 3 and 4) were most influenced by river outflow. The limiting factor for phytoplankton biomass was water turbidity due to the higher values reached in the dry period. The estuarine zone was in a stage of high eutrophication, thus sometimes affecting the waters of the inner shelf. A plataforma de Pernambuco está inserida na margem continental nordeste-leste do Brasil, possui cerca de 187 Km de extensão e se caracteriza por ter uma reduzida largura, pouca profundidade, declive suave, águas relativamente quentes, elevada salinidade. Recebe influência de alguns rios translitorâneos, dentre eles, o rio Jaboatão. O presente trabalho apresentou como objetivo analisar a dinâmica da clorofila a e parâmetros hidrológicos na plataforma continental de Pernambuco sob o efeito da pluma do rio Jaboatão. Foram realizadas coletas bimestrais, no período chuvoso e estiagem, em um ponto na zona estuarina e quatro ao longo plataforma continental adjacente. Os parâmetros avaliados foram: clorofila a, salinidade, oxigênio dissolvido, material particulado em suspensão e nutrientes inorgânicos dissolvidos. A maioria dos parâmetros apresentou variação sazonal significativa. A clorofila a no estuário variou de 2,89 à 34,71 mg.m−3 e na plataforma continental de 0,21 à 9,67 mg.m−3 no período de estiagem e, no período chuvoso, apresentou uma variação no estuário de 0,79 à 12,46 mg.m−3 e na plataforma de 0,26 à 4,59 mg.m−3. De acordo com ACP, a clorofila a apresentou uma relação direta com a temperatura e taxa de saturação do oxigênio e inversa com pH, salinidade e transparência da água. Os pontos da plataforma que mais sofreram influência do deságüe fluvial foram os pontos centrais P3 e P4. O fator limitante para a biomassa fitoplanctônica foi a turbidez da água e os maiores teores foram observados no período de estiagem. A zona estuarina encontra-se em um elevado processo de eutrofização antrópica e, desta forma, vem interferindo na qualidade das águas da plataforma continental. [ABSTRACT FROM AUTHOR]

Rosário, R.P., Borba, T.A.C., Santos, A.S., and Rollnic, M., 2016. Variability of Salinity in Pará River Estuary: 2D Analysis with Flexible Mesh Model. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 128-132. Coconut Creek (Florida), ISSN 0749-0208. This research aims to study the spatial and temporal variability of the salinity in the Pará River Estuary. The Pará River estuary is among the largest in Brazil, with a mouth of approximately 60 km wide. The Pará River is not a true river because it does not have a spring, but is a hydrographic mesh that receives outflow of several water bodies. There is an ingestion of salt in the Pará River Estuary, different of what occurs within Amazon River, that leads estuarine characteristics onto the continental shelf. The model was implemented based on flexible mesh in the estuarine area of the Amazon River and Pará River basin for one-year simulation. The software D-Flow FM was used to perform hydrodynamic model and, D3D-D-Waq to water quality model. These experiments support a conceptual description of haline dynamics of this system to produce information regarding different scenarios in the region. Fieldworks were made (25h - three points in estuary) in low, high, and transitional rivers discharge in order to evaluate the model performance. The main conclusions are: the numerical modeling showed an upstream saline intrusion about 130 km for the dry period (October to December) and about 70 km for the rainy period (January to May). 2D barotropic condition shows river discharge as the most important force that control the variation of saline intrusion due to the reduction of freshwater flow in the system. [ABSTRACT FROM AUTHOR]

Osborne, P.D. and Forest, A., 2016. Sediment dynamics from coast to slope - Southern Canadian Beaufort Sea. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 537-541. Coconut Creek (Florida), ISSN 0749-0208. Profound changes in cross-shelf sediment fluxes are anticipated in coming decades in the southern Canadian Beaufort Sea where an accelerated increase in temperature could lead to large changes in Arctic river hydrology and coastal-marine geomorphologic processes. In the past decade sediment exported to the Beaufort Shelf has increased while sea level pressure has increased accelerating the Beaufort Gyre, strengthening coastal upwelling and expanding the Mackenzie River plume offshore. Sea-ice extent has decreased while storminess has increased increasing wave action, coastal downwelling, current surge and resuspension and transport on the shoreface and shelf. This paper investigates mechanisms, quantities and rates of sediment transport operating in this cold continental shelf-slope environment. Past studies from more than 2 decades of research are compared with recent measurements to develop improved estimates of sediment sources, pathways, fate and fluxes across the shelf and slope. In particular, we explore connections between data from a long term mooring observatory deployed over the continental shelf and slope during the ArcticNet-Industry Partnership (2009-2011) and Beaufort Regional Environmental Assessment (BREA 2011-2015) to those acquired in studies focusing on nearshore and shoreface. Sediment fluxes from the Mackenzie River and erosion of permafrost coasts are compared with outer shelf-slope measurements of settling particles and near-bottom fluxes. In turn, the role of atmospheric and cryospheric processes in forcing sediment transfer from coast to slope is investigated to assess system response to changing climate and evaluate implications for marine hydrocarbon resource development along the continental margin of the Arctic Ocean. [ABSTRACT FROM AUTHOR]

Bahmanpour, M.H.; Pattiaratchi, C., Wijeratne, E.M.S., Steinberg, C., and D'Adamo, N., 2016. Multi-year observation of a boundary current along the shelf edge of North Western Australia. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 517-521. Coconut Creek (Florida), ISSN 0749-0208. Analysis of multi-year current meter data across North West shelf of Australia identified various aspects of the mean flow in a macro-tidal environment. Main features of the flow appear to be a continuous alongshore south-westward flow, i.e., Holloway current located along the continental shelf edge in depth 100-200 m. Annually, the current transports ∼ 1 Sv of lower salinity, higher temperature water from the tropical regions to North West Cape. The Holloway current is at its maximum intensity (up to 2 Sv) during autumn/winter (Apr-Jul) when the winds are either weak or the region is dominated by south-east trade winds. Unlike alongshore flow, cross-shore structure of the flow is fairly complex and shows variations with depth and season. A new mechanism is proposed to justify the observed intensification of the flow in austral autumn that is closely related to the seasonal cycle of sea level around Australia. Each year, due to the monsoon cycles there is a high sea level anomaly that peaks in February in the Gulf of Carpentaria in the upstream side of the Holloway current that manifests itself as southward progressive high sea level anomalies in the following months along the West Australian coastline. Observed onshore fluxes can also have some implications for the strength of the Holloway current. [ABSTRACT FROM AUTHOR]

Gallop, S.L.; Bryan, K.R.; Pitman, S.J.; Ranasinghe, R., and Sandwell, D., 2016. Pulsations in surf zone currents on a high energy mesotidal beach in New Zealand. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 378-382. Coconut Creek (Florida), ISSN 0749-0208. The exchange of material between the surf zone and continental shelf can be driven by pulsations in rip current velocities. However, there is a poor understanding of the relationship of these pulsations to surf zone morphology and material exchange. Moreover, understanding of rip current dynamics has focused mainly on single-barred beaches in an intermediate state, and there have been few studies on high energy beaches. Therefore, this paper undertakes preliminary research on surf zone current velocity pulsations, on a high energy beach in New Zealand. This initial analysis presents results from two days of measurements using Acoustic Doppler Velocimeters and Lagrangian GPS drifters. Drifters revealed pulsations in current velocities on the order of ∼0.5-2 m s−1 throughout the surf zone, whether inside a rip current circulation cell or not. More infragravity wave energy was associated with constant pulsations in current velocity, and lower infragravity energy with pulsation bursts, lasting 5-10 minutes, interspersed with periods of relatively constant velocity lasting 15-25 minutes. However, higher wave conditions also reduced the exit rate from the surf zone. [ABSTRACT FROM AUTHOR]

Mahjabin, T.; Pattiaratchi, C., and Hetzel, Y., 2016. Factors influencing the occurrence of Dense Shelf Water Cascades in Australia. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 527-531. Coconut Creek (Florida), ISSN 0749-0208. Transport of inshore waters and suspended material off the continental shelf by Dense Shelf Water Cascades (DSWC) has important ecological and biogeochemical implications in Australian waters. Because of high rates of evaporation, denser saline water occurs in the shallow coastal regions around Australia, setting up horizontal density gradients that can drive DSWC. Ocean glider data available from the Integrated Marine Observing System (IMOS), which is operated by the Australian National Facility for Ocean Gliders (ANFOG) located at the University of Western Australia, were used to measure cross-shelf density profiles under varying wind and tide conditions for seven contrasting regions around the entire continent. Overall 97 sets of spatial and temporal resolution data from year 2008 to 2015 collected by the ocean gliders and analysed with a subset presented here. Data from 19 transects covering the years 2012 to 2015 for the Pilbara region of Western Australia, indicated that cascades occur during the autumn and winter due to cooling of the coastal waters which already have higher salinity due to evaporation during the summer months. The cross-shelf density gradient in this continental shelf was found to be maximum in July with a value of 14.23×10−6 kg m−4. [ABSTRACT FROM AUTHOR]

Mascarenhas, A.C.C.; Gomes, G.S.; Lima, A.P.Y.; Silva, H.K.N.; Santana, L.S.; Rosário, R.P., and Rollnic, M., 2016. Seasonal variations of the Amazon River plume with focus on the eastern sector. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 532-536. Coconut Creek (Florida), ISSN 0749-0208. The Amazon Continental Shelf (ACS) is a highly dynamic environment as a result of physical processes (tidal, current and wind) and the large river discharge from Amazon and Pará Rivers. This research aims to determine seasonal variations of the plume of the Amazon River in the eastern sector, near the Pará River mouth. Five oceanographic campaigns were conducted on the ACS: April and October 2013; May, July and October 2014. The sampling line followed the shape of the Cabo Maguari (Marajo Island) to 260 km in the shelf break. Nine vertical profiles of conductivity, temperature and pressure and turbidity were collected. It reaches a perpendicular distance up to 200 km from the coast during period of maximum rivers discharge (April and May). During low river discharge (October 2013 and 2014), the plume was restricted to 30 km and presented relative high levels of salinity (20 PSU). The Coastal Water, characterized by high temperatures and low salinity was limited to about - 15 m deep. The Tropical Surface Water, which is considered a high value of salinity and water temperature, was identified in the last sample point to 260 km from the coast in 2014. This water body characteristics is commonly found in the North Brazil Current, then it can be concluded that water mass invades the Amazon continental shelf. Even in low discharge conditions, adjacent ocean water do not invade the the Amazon River mouth, only the Pará River estuary. Because of that, these estuaries present different physical and biological processes. [ABSTRACT FROM AUTHOR]

Park, J.-H.; Kim, Y.S.; Lee, H.J.; Lee, H.-Y.; Ha, H.K.; Park, Y.-G.; Jeon, C., and Hirose, N., 2016. Internal tide-induced enhancement of cold water intrusion on the continental shelf of the Korea Strait. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 542-546. Coconut Creek (Florida), ISSN 0749-0208. The Korea Strait bottom cold water (KSBCW), characterized by its temperature < 10°C, is believed to originate from the deep basin of the southwestern East/Japan Sea with a maximum transport in August/September. Although previous studies have suggested possible causes of the enhanced KSBCW intrusion in summer, its mechanism is not yet clear. Here we investigate if tides can affect the strength of KSBCW intrusion using numerical simulations. We utilize a high-resolution regional ocean model with 1/108° grids, covering the Korea Strait and the southwestern East/Japan Sea. Numerical simulations are conducted for several cases, which include semidiurnal tides (M2+S2), diurnal tides (K1+O1), and wind forcings differently to examine their effects on the intrusion. Simulation results reveal that the energetic semidiurnal internal tides, generated around the continental shelf in the northern part of the Korea Strait, can induce the KSBCW intrusion by the internal tidal pumping effect. Two cases including the four major tides reproduce at best a dome-shaped bottom cold water lower than 10°C impinging on the slope southeast coast of Korea, consistent with historical monthly-mean temperature fields. Long-term ferry boat ADCP measurements (> 10 years) across the Korea Strait show that southwestward KSBCW intrusions get stronger 2-3 days after spring tides in summer and fall when the semidiurnal internal tides are strengthened, supporting our simulation results. We therefore propose that the maximum KSBCW intrusion in August/September is caused by the energetic semidiurnal internal tides. [ABSTRACT FROM AUTHOR]

Kim, G.H.; Jin, S.B.; Hyun S.G., and Yoon, S.B., 2016. Resonance of 2011 East Japan Tsunami over Continental Shelf along Ibaraki Coast of Japan. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1137 - 1141. Coconut Creek (Florida), ISSN 0749-0208. From the wavelet analyses of the tsunami waveforms of the 2011 East Japan Tsunami measured at several stations it is found that the tsunami waves are resonated at the coast of Tokai-Daini nuclear power plant in Ibaraki bay of Japan. For the investigation of this phenomenon numerical simulations are conducted. From the numerical simulations it is understood that the trapping of incidence tsunamis due to the concave shape of the bay and the continental shelf near the entrance of the bay are responsible for the resonance of tsunami waves. The reflections of tsunami waves from land boundaries outside the Ibaraki bay contribute also to the long-lasting tsunami behavior in this bay. [ABSTRACT FROM AUTHOR]

Makowski, C.; Finkl, C.W., and Vollmer, H.M., 2016. Classification of continental shelves in terms of geospatially integrated physiographic realms and morphodynamic zones. The continental shelf off southeast Florida contains a range of benthic environments that are discernible via remote sensing platforms because of low turbidity in the water column. Using the Geospatially Integrated Seafloor Classification Scheme (G-ISCS), physiographic realms and associated morphodynamic zones were cognitively interpreted and classified at a nominal scale of 1:6000 across four remote sensing platforms ( i.e. GeoEye IKONOS-2, Landsat-5 Thematic Mapper [TM], Landsat-7 Enhanced Thematic Mapper [ETM], and National Agriculture Imagery Program [NAIP] high-resolution aerial orthoimagery). Attribute tables were created in conjunction with interpretations to quantify and compare spatial relationships between classificatory units and the different remote sensing platforms. Resultant maps exported from ESRI ArcGIS® ArcMap software showed that while IKONOS-2 satellite imagery and NAIP aerial orthoimagery provided the greatest detail, classification of physiographic realms and morphodynamic zones was still possible using TM and ETM satellite images. Overall, it was determined that IKONOS-2 provided the most beneficial imagery when applying such a classification of coastal and seafloor features. It is postulated that accurate delineation of physiographic realms and morphodynamic zones can provide a foundation for more in-depth biogeomorpholocial classification ( e.g., further subdivision into benthic geoforms, coastal landforms, biological cover) along continental shelves. [ABSTRACT FROM AUTHOR]

Stull, K.J.; Cahoon, L.B., and Lankford, T.E., 2016. Zooplankton abundance in the surf zones of nourished and unnourished beaches in southeastern North Carolina, U.S.A. Surf zones are poorly studied in comparison to adjacent estuarine and continental shelf ecosystems, partly owing to their dynamic, high-energy environment that is often difficult to sample. This study quantified zooplankton abundance in the surf zone at eight sites along three beaches in SE North Carolina between November 2008 and June 2010, encompassing a beach-nourishment cycle at four sites in early 2010. A Before-After/Control-Impact (BACI) sampling design tested the effects of beach nourishment on zooplankton abundance at both medium- (2-3 months) and short-term (2-3 weeks) time scales. Zooplankton abundances in the surf zone ranged from 386-54,900 zooplankters m−3 and averaged about 8240 individuals m−3, an order of magnitude higher than in nearby coastal ocean environments but not as high as in nearby rivers and estuaries. Changes in phytoplankton biomass in the surf zone had a significant effect on meroplankton but not on holozooplankton abundances. Beach nourishment did not have significant effects on zooplankton abundances in the surf zone during this study. The surf zone offers an important food resource for planktivorous fishes and may be an important link between coastal and estuarine communities. [ABSTRACT FROM AUTHOR]

Testut, L. and Unnikrishnan, A.S., 2016. Improving modeling of tides on the continental shelf off the west coast of India. Global tidal solutions are sometimes inaccurate in coastal regions. This is particularly true in some regions of the northern Indian Ocean, which are characterized by wide continental shelves and large tidal ranges. We show that these global solutions are inaccurate on the shelf region off Mumbai, off the west coast of India. In this region, the shelf is very wide, and it opens into the Gulf of Khambhat, where large tides are observed. Moreover, in regions of large semidiurnal tides in the Bay of Bengal, such as the head Bay, Gulf of Martaban, etc., global tidal solutions are not accurate. In the present work, we focus on the shelf region off the west coast of India. We used a new approach in developing a high-resolution hydrodynamic tidal model for the inner shelf region (8°N to 22°N). The open boundary of the model is aligned to the altimetry tracks, which allowed us to prescribe boundary conditions obtained directly from observations. We show that the tidal solutions at the coast are much improved compared with those obtained from the global solutions and that on the wide shelf portion and the Gulf of Khambhat the improvement has been considerable. [ABSTRACT FROM AUTHOR]

Luz Clara, M.; Simionato, C.G.; D'Onofrio, E., and Moreira, D., 2015. Future sea level rise and changes on tides in the Patagonian Continental Shelf. We investigate the effect of the future sea level rise (SLR) on the propagation of tides in the Patagonian Shelf by means of numerical simulations. Using a barotropic implementation of the Model for Applications at Regional Scales (MARS), we obtain solutions for scenarios which represent the present condition and potential future SLRs of 1, 2, and 10 m. The effect of flooding of low-lying areas is studied, and its influence on the propagation of tides in the region is discussed. Due to the coastal morphological features and the sense of tidal wave propagation in the Southern Hemisphere, inundation does not significantly modify the solution in the Patagonian Shelf; nevertheless, results are substantially changed in the much lower Northern Argentinean Shelf, north of 40° S, where dissipation is increased. The amplitude of M2 responds to SLR in a spatially nonuniform manner. The response is nonlinear, particularly in regions close to the amphidromic points. Tidal dissipation by bottom friction increases consistently by 16% for the more extreme scenario with a generalized increment of tidal amplitudes, and therefore currents, over the Patagonian Shelf. Changes in the extension and position of tidal fronts are also explored. The results suggest that changes will be significant, with a reduction of the mixed areas in Cabo Blanco and San Sebastián and an increment of them in the vicinity of Península Valdés. Physical mechanisms that explain the observed modifications in the tidal regime are the changes with SLR of the speed of the tidal wave, the Rossby radius of deformation, the energy dissipation by bottom friction, and the resonant properties of the basin. Similarly to numerical studies performed for other coastal areas of the world, results indicate that important changes in the characteristics of tides can occur if SLR is large. [ABSTRACT FROM AUTHOR]

Zhang, L.; Xu, J., and Peng, Y., 2015. Neotectonic movement and seismic activity in the East China Sea. The East China Sea region in this paper mainly includes the continental shelf of East China Sea and Okinawa trough. The geological structure in the region basically belongs to the extension part of China's east mainland to the sea area. In Cenozoic, this area developed the East China Sea shelf basin, Diaoyu uplift fold zone, and Okinawa trough basin. Since East China Sea is located in the bonded zone of continental plate and the Philippines Sea plate, the neotectonics and the geological structure generated since the Middle Miocene are unique and complex. Basing on fully interpreting the related data and research achievements of previous researchers, this study profoundly analyzed and studied the characteristics of the neotectonics in East China Sea region from a perspective of tectonic landform, geological structure, and seismic activity etc. On this basis, it further discussed the dynamic conditions and seismic activity characteristics of neotectonics in East China Sea area. [ABSTRACT FROM AUTHOR]

Finkl, C.W. and Makowski, C., 2015. Autoclassification versus cognitive interpretation of digital bathymetric data in terms of geomorphological features for seafloor characterization. The determination of seafloor geomorphological features has always been a difficult task, and it was not until the advent of marine remote sensing techniques that seafloor features could be accurately discerned. Airborne acquisition of digital bathymetric data provides a wealth of information that can be interpreted in different ways. This paper considers the pros and cons of computerized autoclassifications versus cognitive interpretations of seafloor features. The continental shelf off the southeast Florida coast contains LADS (laser airborne depth sounding) surveys that are here used to compare and contrast automated classifications of bathymetry with cognitive differentiation of marine geomorphological features. There are advantages and disadvantages associated with each approach, and the choice of methods depends on the purpose or goals of the project. Once seafloor features have been cognitively discerned from enhanced, color ramped, and vertically exaggerated bathymetry, machine classifications can be compared with known units. Using ArcGIS® ArcMap software, five- and seven-class unsupervised isocluster autoclassifications were found to moderately represent known bottom topography, whereas the interactive supervised autoclassification closely approximated cognitively discerned bathymetric patterns. Hand-drawn or digitized cognitively derived maps were more generalized than supervised computerized classifications based on training fields. Overall, both methods were found to be beneficial approaches, as they complement each other. [ABSTRACT FROM AUTHOR]

Schiller, R.V. and Kourafalou, V.H., 2014. Loop current impact on the transport of Mississippi river waters. River plume studies have traditionally focused on coastal and shelf circulation. Here, we examine novel interactions of a large river plume with offshore flows, which introduces additional export pathways for the riverine waters. We show the impact of the Loop Current System (LCS) on the offshore transport and fate of Mississippi River (MR) plume waters. The high-resolution Northern Gulf of Mexico (NGoM) model, nested in a data-assimilative, regional, Gulf of Mexico model, was employed for a 5-year, realistically forced simulation. Model results, in tandem with satellite data, demonstrate that the entrainment of MR waters by the LCS varies interannually and extends pathways of shelf cross-marginal transport to the basin interior and beyond. Plume-to-LCS interactions are determined by episodic northward intrusions of the LCS in the NGoM. If the intrusion is very close to the MR Delta, plume waters can be entrained with little contribution from winds. If the intrusion is farther offshore and lasts for months, LCS entrainment may be modulated by wind forcing because plume transport can change from an along-shelf to an exclusively across-shelf regime. Seasonal changes in river discharge did not have a direct influence on the transport induced by LCS intrusions. However, high-frequency (daily) variability of the river discharge induced by the Mississippi and 16 other major rivers was important and played a role in the overall NGoM freshwater transport. During the 5-year period, plume-to-LCS interactions corresponded on average to ∼11% of the yearly net offshore freshwater transport near the MR Delta. Model results were supported by satellite and in situ observations that demonstrate the far-reaching potential of MR waters as they are traced to the SE Gulf of Mexico and the Florida Keys. This study demonstrates how across-basin, connectivity pathways for riverine waters may be affected by local coastal-to-offshore interactions induced by a large-scale current system. [ABSTRACT FROM AUTHOR]

Summer and fall inner-shelf flow characteristics, including the vertical current structure, obtained from three WAVCIS (WAVE-Current-surge Information System) stations off the Louisiana coast were analyzed to delineate the hydrodynamic conditions that contribute to the formation of seasonal hypoxia at each station location. Two of the WAVCIS data stations used for analysis are located west of the Mississippi bird-foot delta, whereas the third is located east of the delta. Relatively small vertical gradients in the horizontal velocity current (i.e., u and v velocity components) were observed during summer (2009) for both CSI-6 and CSI-9 stations, which are located well inside the hypoxia-prone zone west of the delta. In contrast, the summertime vertical gradient of horizontal current at CSI-16 (located east of the delta) was significantly higher than that of western stations. Significant differences in the vertical gradient of flow velocities along with contrast in water column density gradient during the summer culminated in a strong stratification, which is considered the main physical requirement for the formation of hypoxia. A computed criteria based on the Richardson number also pointed to higher potential for stratification at both stations west of the delta, whereas the water column east of the delta still remained subject to vertical mixing. Furthermore, summertime current fields at CSI-6 and CSI-9 were significantly less compared with CSI-16, suggesting less reoxygenation driven by advection from surrounding waters. These conditions may exacerbate hypoxia. [ABSTRACT FROM AUTHOR]

Sánchez-Arcilla, A., González-Marco, D., Sospedra, J., Palomares, A., Sierra, J.P., Schuon, F., Espino. M., Grifoll, M., Pallarés, E., Jiménez, P.A. and Navarro, J. 2013. Meteo-oceanographic simulations and observations to assess the potential of offshore wind farm in a NW Mediterranean shelf. Renewable marine energy is important in squeezed Mediterranean coastal zones. Wind turbines deployed over the narrow Catalan continental shelf require accurate wind/wave/current fields for a reliable design, operation and maintenance. This paper presents the large (comparative to other open sea areas) errors in meteo-oceanographic predictions for semi enclosed domains such as the coastal sea off the Ebro Delta coast. The emphasis is on the sequence of high resolution coupled and nested models and the role of in situ collocated measurements for calibration and validation. [ABSTRACT FROM AUTHOR]

Teixeira, C. E.P. and Machado, G. T., 2013. On the temporal variability of the Sea Surface Temperature on the Tropical Southwest Atlantic Continental Shelf In this study, we used 29 years of daily 4-km AVHRR Pathfinder Version 5.2 (PFV5.2) data to study the SST temporal variability over the continental shelf in the Southwestern Tropical Atlantic Ocean (SWTA) (1 to 6° S and 41 to 35 W). Firstly, we evaluated the cloud cover and assessed the annual and semi-annual deterministic signals using a harmonic analysis. The annual plus the semi-annual cycles were removed from the original data and a low-pass filter was used to estimate the contribution of the inter-annual component. Finally, the inter-annual signal was also removed and the variance associated to the remaining residuals was calculated to address the intra-annual component. We show that the region is covered by clouds - and SST data unavailable - between 40% and 60% of the time. The annual signal explains most of the variability over the area with a coefficient of determination higher than 70% and amplitudes ranging from 1° to 1.5°C. The amplitudes increase eastwards and towards the coast. The phase of the annual cycle presents values between 40 and 60 days with respect to the 1st of January, occurring earlier over the eastern continental shelf. The semi-annual signals present amplitudes close 0.5 °C in most of the region decreasing towards offshore regions. The continental shelf as whole, experienced weak inter-annual variability with variance values around 0.2 °C. After the annual and semi-annual signals were removed, the inter-annual signal explains 30-45 % of the residual. The intra-annual variability presents variance values between 0.2 and 0.3°C and explains most of the residual variability. Both inter and intra-annual SST variability in the SWTA is spatially homogenous. For the first time, the SST temporal variability ranging from sub-seasonal to inter-annual was addressed in the SWTA continental shelf region. In light of the results, we have showed that the SST in the Tropical Southwest Atlantic continental shelf presents a small temporal and spatial variability. Most of the SST is explained by the annual cycle followed by the intra-annual variations. [ABSTRACT FROM AUTHOR]

Grifoll, M., Gracia, V., Fernandez, J. and Espino, M. 2013. Suspended sediment observations in the Barcelona inner-shelf during storms. This contribution describes in detail the Suspended Sediment Concentration (SSC) obtained from an observational set at 24 m depth in the Catalan inner-shelf (North-western Mediterranean Sea) analysing the dominant processes affecting sediment dynamics during storm events. A clear correlation between SSC, energetic waves, and along-shelf currents events has been found. Peaks in river discharge associated to rainy events are also correlated with SSC measurements. Measured conditions highlight the different sediment dynamic situations present during short-term events such as 'wet' and 'dry' storms with similar wave height. SSC observed during 'dry' conditions are correlated with wave action. On the other hand, SSC peaks during 'wet' conditions are primarily caused by wave action, along-shelf current, and river discharge. Observed sediment fluxes during storms are larger in spring than during fall. Although the observations present similar characteristics to other inner-shelf regions in the NW Mediterranean Sea, the results reveal a non-negligible influence of the along-shelf current in sediment dynamics. The results presented here contribute to advance in the understanding of sediment dynamics in wave-dominated regions such as the Catalan shelf. [ABSTRACT FROM AUTHOR]

Fine sediment (silt and clay) plays an important role in the physical, ecological, and environmental conditions of coastal systems, yet little is known about the dispersal and fate of fine sediment across coastal margin settings outside of river mouths. Here I provide simple physical scaling and detailed monitoring of a beach nourishment project near Imperial Beach, California, with a high portion of fines (~40% silt and clay by weight). These results provide insights into the pathways and residence times of fine sediment transport across a wave-dominated coastal margin. Monitoring of the project used physical, optical, acoustic, and remote sensing techniques to track the fine portion of the nourishment sediment. The initial transport of fine sediment from the beach was influenced strongly by longshore currents of the surf zone that were established in response to the approach angles of the waves. The mean residence time of fine sediment in the surf zone-once it was suspended-was approximately 1 hour, and rapid decreases in surf zone fine sediment concentrations along the beach resulted from mixing and offshore transport in turbid rip heads. For example, during a day with oblique wave directions and surf zone longshore currents of approximately 25 cm/s, the offshore losses of fine sediment in rips resulted in a 95% reduction in alongshore surf zone fine sediment flux within 1 km of the nourishment site. However, because of the direct placement of nourishment sediment on the beach, fine suspended-sediment concentrations in the swash zone remained elevated for several days after nourishment, while fine sediment was winnowed from the beach. Once offshore of the surf zone, fine sediment settled downward in the water column and was observed to transport along and across the inner shelf. Vertically sheared currents influenced the directions and rates of fine sediment transport on the shelf. Sedimentation of fine sediment was greatest on the seafloor directly offshore of the nourishment site. However, a mass balance of sediment suggests that the majority of the fine sediment moved far away (over 2 km) from the nourishment site or to water depths greater than 10 m, where fine sediment represents a substantial portion of the bed material. Thus, the fate of fine sediment in nearshore waters was influenced strongly by wave conditions, surf zone and rip current transport, and the vertical density and flow conditions of coastal waters. [ABSTRACT FROM AUTHOR]

The Gulf of Mexico (GOM) continental shelf, extending approximately 1600 km from the Florida west coast to the U.S.Mexico border, is a large sedimentary basin that has been the focus of much geologic study and surveys during the past 70 years, related mostly to oil and gas exploration. Relatively little attention has been focused on mapping and assessing offshore sediment character and resources, such as sand. It is increasingly recognized, however, that baseline scientific information on seafloor sediment character and composition is needed for managing and protecting natural resources and for providing information on sand availability and quality for potential use in a variety of coastal restoration and protection projects in all five of the states from Florida to Texas. The geomorphologic character and shallow sedimentary stratigraphy of the GOM shelf has been determined over geologic time by sediment inputs from rivers; sea-level fluctuations up to 120 m, resulting in transgressions and regressions of the shore; and frequent storms. These processes have resulted in deposition, reworking, and preservation of a variety of sand bodies, both on the seafloor and in buried, ancestral stream channels. Sand bodies of highly varying grain size, sorting, color, and composition are present throughout parts of the GOM inner shelf, varying greatly in size and number and often overlain or admixed with finer-grained, muddy sediment. The shelf sand bodies tend to be fine grained and are often mixed with muddy or organic detritus as well as carbonate shell material. The GOM shelf is mantled with sand mostly off the Florida shore, and sediments become progressively finer and muddier westward across the Alabama, Mississippi, Louisiana, and Texas shelf regions. The shelf off each state contains shoals that represent drowned paleoshoreline and buried, ancestral, stream-channel features that originated when sea level was lower than at present and the shore was farther seaward. These shoals offer the best promise as potential sand resources; however, further study is needed to refine these findings based on reconnaissance-scale work. [ABSTRACT FROM AUTHOR]

The oceans are density stratified because of vertical variations in temperature and salinity. Oceanic internal waves can form at the interface (pycnocline) between layers of different water density and propagate long distances along the pycnocline. Internal waves on continental shelves are important because they can attain large amplitudes and affect acoustic wave propagation, submarine navigation, nutrient mixing in the euphotic zone, sediment resuspension, cross- shore pollutant transport, coastal engineering, and oil exploration. Internal waves induce local currents that modulate surface wavelets and slicks, causing patterns of alternating brighter and darker bands to appear on the surface. The surface patterns can be mapped by satellites using synthetic aperture radar (SAR) or visible imagers. The objectives of this article are to discuss methods for remotely studying and mapping ocean internal waves and to present examples illustrating the application of satellite remote sensing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Sediment transport between the emerged land masses and deep marine basins is a fundamental process that affects the exploitation of resources and protection of the environment and its ecosystems. Sediment transport models on the continental shelf are often very complex and subject to semiempirical or empirical equilibrium transport equations that relate sediment fluxes and turbulence to physical properties such as velocity, depth, and characteristic bed-load sediment particle sizes. In engineering applications, errors in these physical properties affect the accuracy of the sediment fluxes. The present analysis details the importance of physical properties to the bed-load fluxes and suggests which parameters have more influence on the final result by providing insight into the relative strengths, weaknesses, and limitations of all the selected 52 bed-load equations for noncohesive particles (sand and gravel are treated separately). Various parameters were first investigated individually to pinpoint the key physical properties that control the errors. Because the existence of strong nonlinearity in most bed-load transport equations precludes analytical approaches, the multilinear regression (MLR) method was used to validate this analysis. Several graphs are presented to emphasize the influencing effect of those parameters that were either used directly or embedded in these equations. The most significant parameters that directly influence the sand particles are θ, ds, and vav, and the embedded parameters are sfτo, θds, and Sfθ. On the other hand, for gravel particles, the most significant parameters are θ, ds, and θcr and qs*, Sfθ, and sfτo, respectively. [ABSTRACT FROM AUTHOR]

During the last decade, global tidal models have spectacularly improved. However, they still have difficulties in resolving tides over continental shelves and near coastlines. This study of tidal propagation from the continental shelf to the North Patagonia Gulfs of Argentina applies a set of three nested high resolution models based on the Hamburg shelf ocean model (HamSOM), where particular attention was paid to the bathymetry and the coast line. The study is complemented by the use of all the tidal gauge and tidal current observations available. Simulations display good agreement with observations, permitting the construction of higher resolution and more reliable cotidal and corange charts. The tidal regime in the area is essentially semidiurnal and dominated by M2. This constituent propagates northward as a Kelvin wave and reaches the gulfs from the south. In their interior an important amplification is observed. Tidal currents are large at the mouths of the gulfs, and weaken toward their interior. The nonlinear transfer of energy from the semidiurnal to higher order harmonics was analyzed. This can be very important in the interior of the gulfs, particularly in Nuevo Gulf and in the northwestern San Matías Gulf, close to San Antonio. Energy flux and energy dissipation by bottom friction has been computed and indicate that this region dissipates 17% of the total energy dissipated on the Patagonian Shelf which, in turn, is one of the most dissipative areas of the world ocean. The Simpson-Hunter parameter computed from the simulations shows that in the mouth of the gulfs, particularly in San Matías and east of the Península de Valdés, the tides are energetic enough to overcome stratification and produce tidal fronts. The locations where tidal fronts are located are highly consistent with results from sea surface temperature and primary productivity data analyzed by other authors. [ABSTRACT FROM AUTHOR]

The North Sea is, to an increasing degree, subject to human activities and interests; a particular example of a user function of this environment is sand extraction. In order to satisfy the demand for sand, tidal sandbanks in some sectors of the North Sea act as a source of sediment, this may lead to the creation of large-scale pits on these bedforms. Sandbanks, which provide protection to adjacent stretches of coastline, are therefore worthy of investigation, especially when their potential as a source of aggregates is taken into account. To investigate seabed dynamics, in general, and to predict the long-term morphodynamics of tidal sandbanks subject to sand extraction, in particular, process-based modelling is a commonly-used method. Different approaches can be considered: (i) based on complex numerical simulations; (ii) or applying an idealised model, designed specifically to describe sandbank dynamics. Herein, the first approach is applied to a case study of the Kwinte Bank; this is a tidally- maintained sandbank, located on the Belgian continental shelf. The modelling is set up using the complex process- based model Delft 3D - Online, the waves were not taken into account. Numerical results and experimental data from a field campaign (undertaken in March 2004) arc compared and show good agreement. Analysis of residual currents indicates a predominance of ebb flow over the bank. However, the residual sediment transport pattern is flood-dominated. The predicted residual sediment transport pattern shows that the Kwinte Bank should be regarded as part of a system of swales and sandbanks. Finally, the long-term evolution is discussed, considering complementary approaches that combine the benefits from the complex numerical modelling with the idealised one. The evolution of a tidal sandbank, after removing an amount of sand, is difficult to predict. No clear tendency is evident in the evolution of the depression area on the basis of the long-term full process-based modelling. However, on the basis of idealised modelling, the anticipated long-term trend of an excavated area is the recovery of the depression, resulting in an equilibrium of the sandbank, over a time-span of a few centuries. [ABSTRACT FROM AUTHOR]

In recent years, the exploitation of marine aggregates is increasing. As an example, on the Belgian continental shelf-one particular sandbank (the Kwinte Bank) is exploited extensively; this has led to the creation of a 5 m deep depression along its central part. In the present contribution, the influence of these bathymetric changes, on erosion and sedimentation patterns are studied, using numerical modelling, in order to obtain an initial impression of the effect of such intense sand extraction on the stability of the sandbank. Different numerical models are utilised, two-dimensional and three-dimensional hydrodynamic models have been used to derive currents, whilst third generation wave models have been used to simulate the waves. Two different models are presented, which calculate the total load sediment transport as a function of the local currents and waves. These models have been used to investigate the erosional and depositional patterns. The use of two different sediment transport models has some advantages, since the results of sediment transport models are still subject to some important uncertainties. The hydrodynamic model results are validated using ADCP current data, confirming the good performance of the models. Likewise the wave models provide good results, comparing their results with data from a buoy. The sediment transport model results were compared to the residual transport patterns, derived from the asymmetry of dunes. The results obtained seem to he in general agreement with these observations. The numerical models are used to simulate the response of the sediment transport to extensive sand extraction from the sandbank. One `worst-case' scenario and two more realistic scenarios were simulated, whilst the effect of these bathymetric changes on sediment transport was studied. The results show that the intense sand extraction does not seem to influence extensively the stability of the sandbank, but that, as a consequence, there is less erosion and deposition. The model results show, for all of the scenarios, a small amount of deposition on the top of the sandbank; this could be an indication of a regeneration mechanism. A trench, created perpendicular to the crest of the sandbank, could be slowly refilled again. The time-scale of this regeneration and the influence of storms remain uncertain. Although the main emphasis of the paper relates to tidal forcing, a brief discussion is included on the influence of wave action, on sediment transport. [ABSTRACT FROM AUTHOR]

The origin and morphodynamic evolution of linear sand banks have been widely studied in recent years. Several investigations have been carried out in order to understand the influence of tide-related parameters, bathymetry and Coriolis force on sand bank formation and maintenance. However, the effect of waves on the net flux of sediments over the sand banks has often been neglected on grounds of the short duration of significant wave activity compared to that of tidal cycles. Nevertheless, the interaction between wave activity and tidal currents leads to a high increase of bottom shear stress, especially at the sand bank crests and, as a consequence, to an increase of sand tranport. This paper investigates the effects of wave activity on the morphology and morphodynamics of the Kwinte Bank (Belgian shelf). Numerical simulations were carried Out under different wave conditions to assess wave influence on sand bank evolution. Model verification involved analysis and comparison with field data collected during two different periods. The study shows that wave activity is not only responsible for a large increase in sediment transport hut also for a change in direction of the net flux of sediments. Moreover, the morphological analysis of several sand banks supports the idea that wave activity might also have an impact on the shape of these sand banks. Wave climate data can be used to study long-term sand bank dynamics. [ABSTRACT FROM AUTHOR]