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Agglutinated foraminifera dominate in temperate salt marsh sediment, making them key indicators for monitoring sea level and environmental changes. Little is known about the biology of these benthic foraminifera because of difficulties in distinguishing live from dead specimens in laboratory cultures. We present data from 10 years of laboratory experiments using comparisons of the agglutinant trochamminids Trochammina inflata and Entzia macrescens and the miliolid Miliammina fusca with the calcareous rotalids Helenina anderseni and Elphidium williamsoni. Specimens were taken from a laboratory mesocosm representing Chezzetcook Inlet, a cool-temperate salt marsh in eastern Canada. We determined culture requirements for the agglutinated foraminifera in Petri dishes over 10–12 week periods. Five inexpensive, non-terminal ways of identifying live organisms were developed: spatial movement, detritus-gathering, attachment, clustering, and test opacity. Comparison with rose Bengal staining showed 30%. Terminal chambers of Trochammina inflata were examined by transmission electron microscopy to visualise food consumption and identify food in digestive vacuoles, both in specimens from mesocosm and in culture. Bacteria and unidentified detritus in the vacuoles establish that this agglutinated species is a saprophagous and bacterivorous detritivore. The adhesive secretions by these species apparently help them gather and possibly farm food while being relatively immobile in the sediments. Our observations of movement and feeding orientation in the agglutinants suggest links between form and function that underscore their value as ultra high resolution sea-level proxies. Mesocosm biomass and abundance counts show that foraminifera represent >50% of the meiofaunal biomass, emphasising their importance in the food web and energy-flow dynamics of temperate salt marsh systems.

Geophysical models propose that a former path of ice retreat can be divided into sea-level zones based on the thickness of ice over the region. The predicted position of these zones fits remarkably closely to the observed positions. Fifteen different, detailed curves of relative sea level have been obtained in the Atlantic Canadian area and three composite curves derived from these data are presented here. These data exhibit highest resolution in the last 4000 years but one area provides a complete record since deglaciation and two others from 7000 ybp to present. A clear trend is apparent in these data: relative sea-level rise is greater seaward of the former ice margin with no former shorelines above present sea level. As one moves towards the former ice center and across the former ice margin, there is evidence of early » sea-level fall but no raised marine features. Closer to the ice center old raised shorelines appear but present sea-level is rising. As one approaches the former ice center, relative sea level is still falling with no evidence of any past relative sea-level rise. Atlantic Canada demonstrates the complex inter-relationships which can develop over short distances between relative sea level and resulting sedimentation. For interpreting relative sea level and sedimentation history in glacial regions, it is critical to locate the position of maximum glacial advance. Finding this position helps delineate the boundary between original areas of erosion and deposition and determines sources and quantities of sediment as sea level modifies a coastline. It also determines whether glacial deposition will be concentrated in terrestrial, continental shelf or continental slope and rise environments. 312Resumen Los modelos geofisicos proponen que el antiguo camino de retroceso glacial puede ser dividido en zonas de nivel del mar, basandose en el espesor del hielo en una region. La posicion predicha de estas zonas encaja en forma remarcable con las posiciones observadas. Quince curvas de nivel del mar relativo han sido obtenidas en la zona atlantica de Canada y tres curvas compuestas derivadas de estos datos se presentan aqui. Estos datos exhiben la mayor resolucion en los ultimos 4000 anos, pero un area provee un registro completo desde la deglaciacion y otras dos desde 7000 AP hasta el presente. Una clara tendencia es aparente: el ascenso del nivel del mar relativo es mayor hacia el mar del antiguo margen glacial sin lineas de costa antiguas por encima del nivel del mar actual. A medida que se desplaza hacia el antiguo centro de la calota y a traves del margen glacial hay evidencia de caida temprana del nivel del mar pero no hay rasgos marinos elevados. Mas cerca del centro, lineas de costa antiguas y elevadas aparecen pero el nivel del mar actual se esta elevando. A medida que uno se acerca al antiguo centro de la calota, el nivel del mar relativo todavia esta cayendo, sin evidencia de ninguna elevacion de nivel del mar relativo en el pasado. El Canada Atlantico demuestra las complejas interrelaciones que pueden desarrollarse en cortas distancias entre nivel del mar relativo y la sedimentacion resultante. Para interpretar la historia del nivel del mar relativo y de la sedimentacion en las regiones glaciales es critico encontrar la posicion del maximo avance glacial. El encontrar esta posicion ayuda a delinear el limite entre las areas originales de erosion y depositacion y determinar fuentes y cantidades de sedimentos a medida que el nivel del mar modifica una linea de costa. Determina asimismo si la depositacion glacial estara concentrada en ambiente terrigeno, de plataforma continental o de talud.

The present study gathers pioneering taxonomical and community data on testate amoebae and agglutinated tintinnids, analyzing their seasonal and spatial distribution patterns in the mesotidal system of the Guadiana Estuary, southeastern Portugal. To evaluate both groups’ potential as bioindicators in climate monitoring and paleoenvironmental reconstructions, their abundance, diversity and living proportions were compared to elevation in relation to mean sea-level, marine influence and to periods of elevated water levels. The distributions of testate amoebae and tintinnid total assemblages were also related to major physicochemical variables by means of multivariate analysis. From 49 surface sediment samples collected in winter and summer 2010, 17 species (25 strains) of testate amoebae were identified (in the 63 m fraction). The Centropyxidae, mainly represented by Centropyxis aculeata, Centropyxis arcula and Centropyxis constricta, had the greatest density (71% of total individuals), while the Difflugidae represented the most species (82% of total species). Higher diversities and densities were observed in winter in the upper estuary, where salinity is negligible, and in the middle estuary where they are concentrated at the lower levels of the intertidal zone. Few or no individuals were observed in the highest marsh zones. In winter, dead testate amoebae were dominant, with empty tests accumulating in the sediments from post-mortem transport by high river discharge. In summer, an increase in the living fraction is observed, with living testate amoebae along the entire estuary, which could indicate that some species are able to live in the lower reaches of the estuary. Along with the testate amoebae, two species of agglutinated tintinnids (>63 m), Stenosemella ventricosa and Tintinnopsis cf. lata, were abundant in the sediments. Their highest abundances were observed in summer. Living individuals were only recorded in summer, mainly in the vicinities of freshwater and sewage outflows, where elevated nutrient concentrations may be expected. The present study demonstrates that both testate amoebae and tintinnids have well defined patterns in their temporal and spatial distribution, offering high bioindicator potential in environmental/climate monitoring studies as well as in paleoenvironmental reconstructions. info:eu-repo/semantics/publishedVersion

The present study analyzes the spatial distribution and seasonal distribution of live benthic foraminiferal communities in the estuary of Guadiana, the fourth largest river on the Iberian Peninsula, and establishes, through statistical analysis, their relationships with a series of environmental parameters. Forty-four superficial sediment samples were collected along distance-to-sea and elevation gradients in the winter and summer of 2010. Fifty-three foraminifera species were identified along the intertidal margins of the estuary. Foraminiferal distribution reflected seasonal variation of environmental factors, whose relative importance varied according to species tolerances. Elevation in relation to mean sea level appeared to be the most important parameter controlling foraminiferal distribution, probably because it combines the effects of a series of other variables (i.e. organic matter, sediment texture, pH and temperature). In the highest marsh areas, where environmental conditions approach survival thresholds, only some agglutinated species are able to survive. In the lower intertidal zone, where subaerial exposure is diminished and environmental conditions are generally less variable, more diverse faunas, mainly composed of calcareous species, prevail. During winter, when fluvial discharge peaks, agglutinated species represent more than 80% of the total individuals. In summer, when marine conditions prevail, calcareous species become more competitive, increase their densities and expand into higher marsh zones and estuarine upper reaches. In the estuary, three different foraminiferal assemblages are distinguished: i) Miliammina fusca assemblage, which dominates in unvegetated areas of the lower marsh and tidal flats of the mid-upper estuary; ii)Jadammina macrescens assemblage, which dominates in the highest marsh areas in the lower estuary; and iii) Ammonia aberdoveyensis assemblage, which dominates the areas of low marsh and tidal flats of the lower estuary. (C) 2014 Elsevier B.V. All rights reserved. Portuguese Foundation for Science and Technology (FCT) [SFRH/BD/28265/2006] info:eu-repo/semantics/publishedVersion

The McMurdo Dry Valleys comprise the largest relatively ice-free area in Antarctica and are characterized by low precipitation rates. Perennial ice cover on the dry valley lakes decreases the amount of solar radiation reaching the water column, thereby reducing the interaction between the atmosphere and the water column. However, the ice partly shelters the lake ecosystems from the harsh Antarctic climate. Two cores, collected from Lake Hoare in the Taylor Valley in 1995, contained testate rhizopods (mostly Arcella ) that have only chitinous organic tests with no agglutinated material, unlike other testate rhizopods that use detrital material to build a test. Additionally, a limited number of possible ostracod carapaces and possible rotifer resting-stage remains were present. The testate rhizopod concentration is generally higher in layers containing abundant bacterial/algal-mat fragments. This reflects the local sedimentation pattern in which layers of alternating mat growth and sediment accumulation on the ice surface subsequently fall to the lake bottom.

SUMMARY This paper examines the influence of fire damage on experimentally measurable modal parameters to explore the potential role of vibration-based structural identification in post-fire condition assessment. Experimental modal analysis of a precast, prestressed concrete roof comprised of modular double-tee joists was performed following exposure to an accidental fire. Empirical evidence of localized structural degradation is identified in the mode shapes, which suggests that modal parameters are sensitive to fire-induced damage in prestressed concrete members. Additionally, measured out-of-plane global modes are correlated with finite element simulations using a model of the as-built roof as well as a model updated using a large set of impact-echo measurements across the double-tee roof to spatially map localized reductions in stiffness. The comparisons support the experimental conclusions and further demonstrate that, by coupling nondestructive techniques, it is possible to construct a validated analytical model of structural components with sufficient fidelity to assess suitability for rehabilitation and reuse. With further development, vibration-based monitoring and structural identification may be an attractive alternative to physical load testing, particularly when the risk of structural collapse under proof testing loads is high. Copyright © 2014 John Wiley & Sons, Ltd.

Reinforced concrete is important for nuclear related structures. Therefore, the integrity of structural members consisting of reinforced concrete is germane to the safe operation and longevity of these facilities. Many issues that reduce the likelihood of safe operation and longevity are not visible on the surface of reinforced concrete material. Therefore, an investigation of reinforced concrete material should include techniques which will allow peering into the concrete member and determining its internal state. The performance of nondestructive evaluations is pursuant to this goal. Some of the categories of nondestructive evaluations are electrochemical, magnetism, ground penetrating radar, and ultrasonic testing. A specific ultrasonic testing technique, namely ultrasonic shear wave tomography, is used to determine presence and extent of voids, honeycombs, cracks perpendicular to the surface, and/or delamination. This technique, and others similar to it, has been utilized in the nuclear industry to determine structural conditions.

In this paper, we reconstruct the Holocene paleoenvironmental evolution of the Guadiana Estuary, southwestern Iberian Peninsula. Two previously studied boreholes (CM3 and CM5) were revisited and analyzed in the light of a foraminifera modern analog approach. Cluster analyses define four assemblages with different biocenotic, taphonomic, elevation and distance-to-sea settings, which serve as a baseline for paleoassemblages interpretation. Faunal changes along the sedimentary sequences, together with previous sedimentological and chronological data, redefine the different phases of environmental evolution in the Guadiana Estuary since ca. 13 kyr cal. BP, with special emphasis on the Holocene marine highstand. Estuarine flooding began synchronously in both locations (ca. 9 kyr cal. BP) but manifested differently in each sedimentary sequence. The most seaward borehole records a more evident and longer highstand (ca. 8.8–3.8 kyr cal. BP), characterized by the occurrence of subtidal environments and by the presence of open marine species (Pararotalia cf. spinigera, planktic forms and a significant number of exotic/allochthonous tests), indicating warmer and more marine conditions than today. In the most landward borehole, the highstand is shorter (ca. 8–7.6 kyr cal. BP) and less intense, characterized by the presence of a diverse, mainly autochthonous, open estuary assemblage, dominated by Ammonia aberdoveyensis and Haynesina germanica. At 4.4 kyr cal. BP, during a long deceleration phase of regional sea-level rise, a short but well-defined pulse of marine influence is recorded in CM5, when open estuarine assemblages reappear and replace marsh agglutinated assemblages, suggesting a new submergence phase. This short event is not identified in the previous works carried out in the same area, thus further data are needed to understand whether it is consequent from a global, warming period or whether it resulted only from local and ephemeral forcing effects. info:eu-repo/semantics/publishedVersion

Short-term monitoring of benthonic foraminifera in Halifax Harbour conducted before, during, and after implementation of an enhanced, municipal pollution-abatement program showed that foraminiferal distribution correlated strongly with the amount of pollution flowing into the harbor. Before enhanced treatment the confined, highly polluted inner harbor and North West Arm contained a fauna of low abundance and diversity, dominated by non-calcareous species with a high percentage of shell deformities and organic inner linings. In contrast the foraminiferal assemblage in the outer harbor, where currents carry away waste material to the ocean, had high diversity and abundance, few shell deformities and organic inner linings, and contained calcareous species. During treatment the composition of the inner harbor assemblage changed dramatically to resemble that of the outer harbor fauna, only to revert to its former characteristics after treatment stopped. This study once again shows that benthonic foraminifera are accurate, quick, and cost effective proxies to monitor continuous environmental changes in polluted environments.

The recent report from Working Group II of the Intergovernmental Panel on Climate Change (IPCC) called for an increased understanding of how groundwater interacts with the ocean-atmospheric system. This remains a prerequisite to better understand how groundwater will respond to climate change. However, achieving this goal is hampered by several problems, including: (1) our minimal understanding of how current groundwater conditions evolved and responded to previous climatic perturbations, and (2) the scarcity of techniques available for evaluating prehistoric groundwater. Subfossil benthic foraminifera in underwater caves are an overlooked method of evaluating prehistoric groundwater on coastal carbonate terrain because they provide a proxy for groundwater salinity and circulation. Twelve radiocarbon dates and foraminiferal paleoecology from two sediment cores obtained from Green Bay Cave (GBC), Bermuda, provide the first Holocene-scale groundwater reconstruction. First, the cave floor (− 20.7 mbsl) was flooded at 7.7 ka as North Atlantic sea level and groundwater rose in near synchrony. Over the Holocene, groundwater conditions (salinity, circulation and degree of oxygenation) shifted a minimum of five times, primarily in response to sea-level rise. Most importantly, we provide evidence that a prehistoric meteoric lens collapsed at 1.6 ka as sea-level rise breached a local sill and completely altered Bermudian coastal circulation. The complete loss, or retreat, of a groundwater mass associated with a minor sea-level change validates some numerical predictions that small changes in sea level can destabilize coastal groundwater resources, when coastal geometry and circulation are considered.

Supersonic ejectors have been used in cooling/refrigeration applications since the early 1900s. Interest in supersonic ejectors has been rekindled by recent efforts to reduce energy consumption; ejector refrigeration systems can be powered by solar energy or by waste heat generated by another process. This paper describes an experimental test bench using R245fa that was assembled and operated at CanmetENERGY in Varennes. The results from this test bench provide a source of reference data that may be used to validate numerical models of ejectors that could be used in refrigeration applications. Limited results from two numerical models are presented for comparison; global results from a 1D model and results from a detailed CFD model that show the flow field inside the ejector.

Quaternary climate and sea-level research in coastal karst basins (caves, cenotes, sinkholes, blueholes, etc.) generally focuses on analyzing isotopes in speleothems, or associating cave elevations prior sea-level highstands. The sediments in coastal karst basins represent an overlooked source of climate and sea-level information in the coastal zone, but to accurately interpret these sediments first requires an understanding of the forcing mechanisms that emplace them. In this study, we hypothesize that coastal karst basins transition through vadose, littoral, anchialine, and finally into submarine environments during sea-level rise because groundwater and sea level oscillate in near synchrony in the coastal zone, causing each environment to deposit a unique sedimentary facies. To test this hypothesis, the stratigraphy in twelve sediment cores from a Bermudian underwater cave (Green Bay Cave) was investigated and temporally constrained with twenty radiocarbon dates. The results indicate that we recovered the first succession spanning the entire Holocene from an underwater cave (~ 13 ka to present). The sediments were characterized with X-radiography, fossil remains, bulk organic matter, organic geochemistry (δ13Corg, C:N), and grain size analysis. Four distinct facies represent the four depositional environments: (i) vadose facies (> 7.7 ka, calcite rafts lithofacies), (ii) littoral facies (7.7 to 7.3 ka: calcite rafts and mud lithofacies), (iii) anchialine facies (7.3 to 1.6 ka: slackwater and diamict lithofacies), and (iv) submarine facies (

Three paleoecological studies were conducted on five lagoons and marshes in San Diego County in 1973–1975 and initial results were published in 1976. This paper integrates the earlier results with new palynological evidence, microfossil, and sedimentological data to provide a regional perspective of lagoon, salt-marsh, and climate changes in southern California over the past 8000 years. Foraminiferal species are illustrated and a revised taxonomy is presented. Ostracodes in the surface samples and boreholes of this region are illustrated for the first time. Surface sample data show the relation between microfossil faunal assemblages, modern salinity, tidal exchange, water depth, and salt-marsh elevation in open lagoons at Tijuana estuary, San Diego and Mission bays, and Agua Hedionda, and for hypersaline-to-brackish marshes in the Los Penasquitos wetlands. Drillhole lithofacies in Los Penasquitos, Tijuana, and Mission Bay marshes were dated with seven radiocarbon ages in addition to those published in 1976. The microfossil surface sample data were used to interpret the drillhole records, showing the paleoecological evolution of the wetlands and the variation within and between lagoons located less than 40 km apart. Abundances of planktonic and other nearshore foraminifera show that Los Penasquitos lagoon was much more open in the mid-Holocene compared to today. Palynological data provide the first documentation of mangrove migration as far north as San Diego in the mid-Holocene, which implies warmer winters and wetter summers at that time. Palynostratigraphic data also permit refined timing of recent changes (past 300 years) in lagoonal environments based on use of historical dates for introduced plant species.

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Geological features supporting cold-water coral habitat in Atlantic Canada are reviewed and exemplified using qualitative field observations from the Scotian margin and Southwest Grand Banks, Newfoundland, in the context of regional geology of the Atlantic Canadian continental margin. Coral habitats are concentrated in areas of shelf-crossing troughs and trough-mouth fans associated with glacial ice streams. Most habitat types are supported by glacial or glaciomarine depositional features, although some are supported by erosional features, probably related to subglacial meltwater erosion. Shelf-break and upper continental slope moraine deposits, subject to strong currents, form current-swept cobble-boulder pavements, forming the principal habitats for the large gorgonian corals Primnoa resedaeformis and Paragorgia arborea . At greater depths, upper slope till tongues are upper continental slope gravelly mud deposits, exposed at the surface as isolated cobbles and boulders in a muddy sand matrix. Common skeletal corals in these environments include the large long-lived gorgonian Keratoisis ornata , the smaller gorgonian Acanthogorgia armata , and, in muddy sand between rocks, the small gorgonian Acanella arbuscula . Erosional environments including friable Tertiary mudstones and semi-consolidated Quaternary sediments, colonized by large gorgonians and other corals, were observed in The Gully, the Stone Fence, and the Southwest Grand Banks. Weak bedrock strength may limit the size of large gorgonian coral colonies. Authigenic carbonate crusts, possibly related to cold seeps, may be locally important in supporting coral growth. Predictive models of coral distribution should consider Quaternary and surficial geology.

Despite the importance of the nitrogen (N) cycle on marine productivity, little is known about variability in N sources and cycling in the ocean in relation to natural and anthropogenic climate change. Beyond the last few decades of scientific observation, knowledge depends largely on proxy records derived from nitrogen stable isotopes ( δ 15 N) preserved in sediments and other bioarchives. Traditional bulk δ 15 N measurements, however, represent the combined influence of N source and subsequent trophic transfers, often confounding environmental interpretation. Recently, compound-specific analysis of individual amino acids ( δ 15 N-AA) has been shown as a means to deconvolve trophic level versus N source effects on the δ 15 N variability of bulk organic matter. Here, we demonstrate the first use of δ 15 N-AA in a paleoceanographic study, through analysis of annually secreted growth rings preserved in the organic endoskeletons of deep-sea gorgonian corals. In the Northwest Atlantic off Nova Scotia, coral δ 15 N is correlated with increasing presence of subtropical versus subpolar slope waters over the twentieth century. By using the new δ 15 N-AA approach to control for variable trophic processing, we are able to interpret coral bulk δ 15 N values as a proxy for nitrate source and, hence, slope water source partitioning. We conclude that the persistence of the warm, nutrient-rich regime since the early 1970s is largely unique in the context of the last approximately 1,800 yr. This evidence suggests that nutrient variability in this region is coordinated with recent changes in global climate and underscores the broad potential of δ 15 N-AA for paleoceanographic studies of the marine N cycle.

The foraminifera from a Lower Cretaceous cored interval of Cohasset A-52 well (located on the Scotian Shelf) were used to interpret the depositional environments of these sediments. Paleoenvironmental interpretation was based on the analysis on 41 samples from four cored intervals of the well collected between 2069 and 2219 m below seafloor. The interval consists of 25 m of interbedded gray-black shale, mudstone and sandstone belonging to the Cree Member of the Logan Canyon Formation. The foraminiferal association recorded in the studied samples is comprised mainly of agglutinated specimens of Trochammina, Haplophragmoides, Ammobaculites and Verneuilinoides . A scattered occurrence of calcareous benthic foraminifera and thecamoebians is also recorded. A comparison of these microfauna with modern foraminiferal associations from paralic environments suggests that these sediments were deposited in a Cretaceous marsh–estuarine environment.

Two hypotheses have been proposed to explain the origin of marine isotope stage (MIS) 11 deposits in small Bermudian caves at +21 m above modern sea level: (1) a +21 m MIS 11 eustatic sea-level highstand, and (2) a MIS 11 mega-tsunami event. Importantly, the foraminifera reported in these caves have yet to be critically evaluated within a framework of coastal cave environments. After statistically comparing foraminifera in modern Bermudian littoral caves and the MIS 11 Calonectris Pocket A (+21 m cave) to the largest available database of Bermudian coastal foraminifera, the assemblages found in modern littoral caves – and Calonectris Pocket A – cannot be statistically differentiated from lagoons. This observation is expected considering littoral caves are simply sheltered extensions of a lagoon environment in the littoral zone, where typical coastal processes (waves, storms) homogenize and rework lagoonal, reefal, and occasional planktic taxa. Fossil protoconchs of the Bermudian cave stygobite Caecum caverna were also associated with the foraminifera. These results indicate that the MIS 11 Bermudian caves are fossil littoral caves (breached flank margin caves), where the total MIS 11 microfossil assemblage is preserving a signature of coeval sea level at +21 m. Brackish foraminifera (Polysaccammina, Pseudothurammina) and anchialine gastropods (∼95%, >300 individuals) indicate a brackish anchialine habitat developed in the elevated caves after the prolonged littoral environmental phase. The onset of sea-level regression following the +21 m highstand would first lower the ancient brackish Ghyben-Herzberg lens (

This paper presents new data on distribution patterns of modern benthic foraminifera and other microfossils from the Canadian Arctic, specifically the Beaufort Shelf and slope. The material was collected in June to August of 2004 and is the first of its kind in this area to be collected since 1970. We examined the smaller sizes (45–63µm) as well as N 63µm and discovered that many species had been severely underrepresented in previous studies. Deep sea forms, that had been overlooked previously, were common on the shelf; two species (Elphidiella arctica and Ammotium cassis) appeared in preliminary results to be indicators of methane seepage; and it was possible to make determinations of sea-ice coverage using a combination of foraminifera and tintinnids (planktic ciliates). Our data indicated the presence of many of the same species as previous studies from this area, but improved techniques of sample processing greatly increased the number of specimens and species found (particularly the small deep sea arctic species Buliminella hensoni and Bolivina arctica) which provide much more reliable data for paleoceanographic determinations. One of the primary objectives for this work was to provide baseline data to help determine paleo-ice cover; these data cover a broad range of conditions on the Beaufort Shelf that make it possible to achieve this objective as well as improving

Fossil testate amoebae and their non-marine finds are rare so their ecological importance through Earth history is poorly understood. The Lower Jurassic shallow water black-shales of Trento Platform (north-east Italy) are rich in micro-organisms and contain a thecamoebian and ostracod assemblage representing the first known record of Early Jurassic oligohaline forms from the European mainland. The thecamoebians are represented by the genera Difflugia, Pontigulasia and Centropyxis. The present discovery of Lower Jurassic thecamoebians in fine carbonate organic-rich deposits indicates, for the first time, that these sediments can preserve testate amoebae very well. The occurrence of difflugid testate amoebians confirm a transitional marine-terrestrial habitat, outside large bodies of water, and suggests occasional eutrophication in ephemeral restricted aquatic environment in the Sinemurian–Pliensbachian Trento Platform.

The Mackenzie Trough provides a high resolution signal for paleoceanography as a result of high sedimentation rates at the mouth of the Mackenzie River. Three cores were collected along a transect covering a depth range of 58–671 m and the time period of the last 11 500 cal BP. Prior to the last ∼10 000 cal BP, the distal core is characterized by laminated sediment and a foraminiferal fauna of Arctic Bottom Water calcareous species and abundant planktic foraminifera suggesting little freshwater runoff and (or) perennial sea-ice cover. This occurs at a similar time as laminated sediments from the west of this site, which have been suggested to be part of the Lake Agassiz flood outburst and (or) cold period. If this outburst occurred, the very positive oxygen isotope values from our core (PC3; >+3.0 ppm) indicate that it did not flow through the Mackenzie Trough. After 9000 cal BP, the faunas in the three cores differ because of timing and different water depths. However, it is possible to see a progression of cold saline water prior to 10 000 cal BP, with a freshening of surface water after 10 000 cal BP where tintinnids (brackish water ciliates) occur with incursions of deep water Arctic calcareous species to ∼3000 years BP. A sequence of mixed faunas appears as sea ice returns, at least periodically in the last 3000 cal BP; but (in core PC2 only) a return to more sea ice is recorded by both foraminifera and dinocysts in the last few hundred years.

Deep-sea gorgonian corals secrete a 2-part skeleton of calcite, derived from dissolved inorganic carbon at depth, and gorgonin, derived from recently fixed and exported particulate organic matter. Radiocarbon contents of the calcite and gorgonin provide direct measures of seawater radiocarbon at depth and in the overlying surface waters, respectively. Using specimens collected from Northwest Atlantic slope waters, we generated radiocarbon records for surface and upper intermediate water layers spanning the pre- and post-bomb- 14 C eras. In Labrador Slope Water (LSW), convective mixing homogenizes the pre-bomb Δ 14 C signature (− 67 ± 4‰) to at least 1000 m depth. Surface water bomb- 14 C signals were lagged and damped (peaking at ∼ + 45‰ in the early 1980s) relative to other regions of the Northwest Atlantic, and intermediate water signals were damped further. Off southwest Nova Scotia, the vertical gradient in Δ 14 C is much stronger. In surface water, pre-bomb Δ 14 C averaged − 75 ± 5‰. At 250–475 m depth, pre-bomb Δ 14 C oscillated quasi-decadally between − 80 and − 100‰, likely reflecting interannual variability in the presence of Labrador Slope Water vs. Warm Slope Water (WSW). Finally, subfossil corals reveal no systematic changes in vertical Δ 14 C gradients over the last 1200 yr.

This paper reviews some new data on distribution patterns of modern benthic foraminifera and related organisms from the Canadian Arctic, specifically the Beaufort Shelf and slope. The smaller sizes—45–63 μm as well as >63 μm—were examined, and it was discovered that many species had either been overlooked altogether or severely underrepresented in previous studies. Not surprisingly, the deep-sea forms in particular had been overlooked even though they are present in the shallow shelf sediments in significant numbers. Although the data show many of the same species as previous studies, improved techniques of sample processing greatly increased the numbers of specimens and species found, enhancing the spatial and faunal relationships. These new data change the known faunas and will allow a much more precise indication for paleoenvironmental studies than was previously available. However, the major focus of this paper is taxonomy and illustration of most of these species to update the taxonomy last done in the 1990’s. One new species is reported, Cyclogyra distincta Cole and Scott, and Komokiacea (excluding Rhizammina algaeformis Brady) are reported from the Arctic for the first time as well as a southern immigrant, Elphidiella hannai (Cushman and Grant), which appears to thrive in methane-rich environments in the Arctic.

This study reports and describes fossil thecamoebians from early Cretaceous deposits of Cohasset A-52 well located on the Scotian Shelf. In this paper we illustrate and discuss fossil thecamoebians to provide additional data to the few published reports on this fossil group. The identified taxa are attributed to the genera Cucurbitella, Difflugia and Heleopera , showing a strong similarity with recent thecamoebians. Several other forms with an uncertain generic characterization are are described.

Prestressed concrete exhibits resistance to damage induced by fire and associated elevated temperatures, often permitting reuse of structural elements following exposure to accidental fire. However, prudent determination of suitability for reuse or rehabilitation of fire-damaged prestressed concrete requires a post-fire structural evaluation, which can be greatly aided by application of nondestructive testing for quantitative assessment of residual material properties, structural strength, and serviceability. In this study, a suite of nondestructive inspection and evaluation methods including visual documentation, camber surveying, penetration resistance testing, and impact-echo are applied to fire-damaged and unaffected double-tee joists of a precast, prestressed roof system. Qualitative and quantitative measures of fire damage obtained through the nondestructive tests are presented and strong correlations, in particular between longitudinal wave speed estimates obtained in impact-echo testing an...

This study analyses the taxonomy, ecology and biogeography of the species of benthic foraminifera living on the intertidal margins of the Guadiana Estuary (SE Portugal, SW Spain). Of the 54 taxa identified during sampling campaigns in winter and summer, 49 are systematically listed and illustrated by scanning electron microscope (SEM) photographs. Ammonia spp. were the most ubiquitous calcareous taxa in both seasons. Morphological analysis and SEM images suggested three distinct morphotypes of the genus Ammonia, two of which proved to be Ammonia aberdoveyensis on the basis of partial rRNA analyses. Jadammina macrescens and Miliammina fusca were the most ubiquitous agglutinated taxa in the estuary. Jadammina macrescens dominates the upper-marsh zones almost exclusively, occurring at very high densities. Ammonia spp. are the most abundant in the low-marsh and tidal-flats of the lower reaches of the Guadiana Estuary, but are widespread throughout the estuary, especially during summer when environmental conditions favor their proliferation. Miliammina fusca dominates the sparsely vegetated low-marsh and tidal-flat zones of the upper reaches, where it is associated with calcareous species. Due to its geographical position, the Guadiana system shares characteristics of both Atlantic and Mediterranean estuaries. This is reflected in the foraminiferal assemblages, with a dominance of thermophilous species and an ecological zonation typical of the Mediterranean climatic zone. info:eu-repo/semantics/publishedVersion

Corrosion assessment of embedded steel in concrete structures is generally performed by electrochemical methods that are not fully nondestructive because the device requires connection to the steel. For practical applications, the development of a truly nondestructive technique for the detection of corrosion is desirable. This paper presents an experimental study of a wideband microwave three-dimensional synthetic aperture radar imaging technique applied to reinforced concrete specimens subjected to corrosion. Two orthogonal wave polarization directions were used for this purpose. Two-dimensional microwave image slices were analyzed and compared with the actual loss of steel measured during the destructive testing. As expected, the results indicated that higher-frequency images have higher spatial resolution, while the signal penetration became more limited at these frequencies. Though the relatively high moisture content significantly increased the dissipative properties against electromagnetic propagation, the technique was capable of differentiating between corroded and non-corroded steel bars.

Primnoa resedaeformis is a deep-sea gorgonian coral with a two-part skeleton of calcite and gorgonin (a fibrillar protein), potentially containing long-term records of valuable paleo-environmental information. For various reasons, both radiocarbon and U/Th dating of these corals is problematic over the last few centuries. This paper explores aspartic acid racemization dating of the gorgonin fraction in modern and fossil specimens collected from the NW Atlantic Ocean. Radiocarbon dating of the fossil specimen indicates a lifespan of 700 ± 100 years, the longest yet documented for any octocoral. Gorgonin amino acid compositions were identical in the fossil and modern specimens, indicating resistance to organic diagenesis. Similar to bone collagen, the fibrillar protein of gorgonin may impose conformational constraints on the racemization of Asp at low temperatures. The rate of racemization of aspartic acid ( d / l -Asp) was similar to previously published results from an 1800 year old anemone (Gerardia). The age equation was: age (years BP 2000 AD) = [( d / l − 0.020 (±.002))/.0011 (±.0001)]2 (r2 = 0.97, p d / l -Asp was marginally better than that for 14C dating over the most recent 50–200 years, although the dating error may be improved by inclusion of more samples over a broader time range. These results suggest that d / l -Asp dating may be useful in augmenting 14C dating in cases where 14C calibrations yield two or more intercept ages, or in screening samples for further 14C or U/Th dating.

This short paper summarizes some of the techniques that have been developed and perfected over the last 30 years for use as environmental indicators. Very few fossil groups provide the information that benthic foraminifera and thecamoebians can supply because their distributions and environmental preferences are fairly well known from a large amount of work that has been done on modern distributions and these associations can be used as proxies. In this brief paper several examples are given and briefly described where foraminifera and thecamoebians have been used for detecting sea-level change, pollution detection and monitoring, hurricane periodicity, earthquake precursors, paleoclimate studies and freshwater/marine transitions.

A high-resolution record of sea-level change spanning the past 1000 years is derived from foraminiferal and chronological analyses of a 2 m thick salt-marsh peat sequence at Chezzetcook, Nova Scotia, Canada. Former mean tide level positions are reconstructed with a precision of ±0.055 m using a transfer function derived from distributions of modern salt-marsh foraminifera. Our age model for the core section older than 300 years is based on 19 AMS 14C ages and takes into account the individual probability distributions of calibrated radiocarbon ages. The past 300 years is dated by pollen and the isotopes 206Pb, 207Pb, 210Pb, 137Cs and 241Am. Between AD 1000 and AD 1800, relative sea level rose at a mean rate of 17 cm per century. Apparent pre-industrial rises of sea level dated at AD 1500-1550 and AD 1700-1800 cannot be clearly distinguished when radiocarbon age errors are taken into account. Furthermore, they may be an artefact of fluctuations in atmospheric 14C production. In the 19th century sea level rose at a mean rate of 1.6 mm/yr. Between AD 1900 and AD 1920, sea-level rise accelerated to the modern mean rate of 3.2 mm/yr. This acceleration corresponds in time with global temperature rise and may therefore be associated with recent global warming. © 2005 Elsevier Ltd. All rights reserved.

We have looked at a series of living and total assemblages of foraminifera in cores from two well-studied salt marshes (Chezzetcook Inlet, Canada, and North Inlet, South Carolina) and replotted data from a marsh in Nanaimo, British Columbia. The data from the three sites indicate that: 1) the infaunal living specimens appear to have little impact on the total assemblages at depth; 2) there is little evidence of test breakdown except for the well-known dissolution of calcareous tests that occurs in these acidic marsh sediments, although there is an inexplicable taphonomic breakdown of specimens in the southeastern USA; 3) the upper 1-cm slice of sediment provides a representative assemblage to use as a modern analogue for fossil benthic foraminiferal assemblages (as opposed to larger segments); and 4) foraminifera do not migrate vertically in the sediment to escape seasonal ice. We also include a taxonomic discussion of the most common Trochammina species, since some new names have been assigned to various formae of Trochammina macrescens.

Small vertical variations in occurrences of mangrove foraminifera and arcellaceans (thecamoebians) provide a zonation scheme that is applicable to the study of short-term sea-level change. Sampling along transects was carried out at three sites in southern Brazil and four sites along the Rio de Janeiro lagoon system. The Sai-Guacu fluvial-estuarine point bar that divides the states of Santa Catarina and Parana, and the Capinzal and Veiga islands at the ancient flood tidal delta of the Guaratuba Bay, were sampled during two summers for a total of 42 samples. In the state of Rio de Janeiro, the seaward borders of the Urussanga, Boqueirao and Fora lagoons, which comprise the incipient brackish mangroves of the Saquarema Lagoon system, were sampled in both summer and winter for a total of 17 samples. Three samples were collected during the summer at the freshwater marsh of Jacarepia Lake. These coastal sedimentary environments differ in latitude, climate, physio-chemical conditions, vegetation, and sediment type. Altitude, rate of sediment transport and salinity influence the distribution of three faunal zones: higher, middle, and lower. Statistics on the dead foraminiferal distribution and ecological indications given by live occurrences showed that Haplophragmoides sp. is the dominant species at the uppermost stations (higher high water—HHW, with a 6-cm vertical range) in both Guaratuba and Rio de Janeiro transects, whereas Trochammina inflata dominates the southernmost Sai-Guacu site. The Haplophragmoides - Trochammina association was also the most consistent in both dead and live HHW assemblages. Trochammina inflata and two forms of T. macrescens were found to be salinity-sensitive HHW assemblages, as were Polysaccammina hyperhalina and Miliammina fusca in the Guaratuba intertidal zone. In Saquarema, the intertidal zone is marked by T. macrescens, and Centropyxis aculeata predominates in Jacarepia. The subtidal zone in Parana contains Arenoparrella mexicana, Tiphotrocha comprimata, Trochammina macrescens f. macrescens, and Difflugia oblonga, whereas in Rio de Janeiro, T. macrescens f. polystoma predominates. Similar HHW assemblages are also observed in Oregon, British Columbia, Maritime Canada, and New England. Thus, the assemblages found in Brazil are potentially applicable to the study of sea-level variation as recorded in Quaternary deposits, like their counterparts in temperate marshes. These transects are the first well-constrained vertical transects of mangrove faunas in South America.

Both surface and core studies from two highly impacted estuaries (New Bedford Harbor, Massachusetts, USA and Halifax Harbour, Nova Scotia, Canada) were carried out to determine if benthic foraminifera could be used to detect changes through time in these areas. New Bedford Harbor is in a highly industrialized area that has undergone severe environmental stresses from a variety of sources for almost 400 years, and has been declared an U.S. Environmental Protection Agency (EPA) Superfund site (i.e., a site so impacted that a special EPA fund is set up to clean it up in designated time frame). Halifax Harbour has been subjected mostly to domestic pollution (i.e., organic carbon produced by human wastes), rather than industrial (chemical) pollution since the founding of the city in 1749. Although many geochemical studies have been done in both estuaries, there are few baseline data on the biota. In this paper we use benthic foraminiferal assemblages retrieved from sediment cores to reconstruct biotic changes of the recent past. It is then possible to correlate faunal changes with already known geochemical parameters. The character of the pollution has changed in New Bedford Harbor as remediation efforts have taken hold. This change was detected with the foraminifera. One outcome is that deformities among one species, Haynesina orbiculare, appear to occur simultaneously with high polychlorinated biphenyls (PCB's) in the sediments. In Halifax Harbour, where the largest impact is due to high organic input from domestic sources, species tolerant of low-oxygen conditions are most prominent at present. Core studies show that prior to the rapid growth of Halifax (in the 1960s) the organic input was much lower than at present. The higher input of organic carbon (OC) at present is indicated by foraminiferal species tolerant of high OC in cores since 1960, generally those with agglutinated as opposed to calcareous tests. We define industrial vs. OC pollution in sediments using foraminifera as proxies, and further, the environmental history is accurately depicted without original baseline data. Data from these two estuaries can be compared to other sites where degradation may be in different stages, which can be assessed by looking at foraminiferal faunas in those areas.

The deep-sea gorgonian octocoral Primnoa resedaeformis is distributed throughout the Atlantic and Pacific Oceans at depths of 65-3200 m. It has a two-part skeleton of calcite and gorgonin. Towards the inside of the axial skeleton gorgonin and calcite are deposited in concentric growth rings, similar to tree rings. Colonies were collected from the Northeast Channel (northwest Atlantic Ocean, southwest of Nova Scotia, Canada) from depths of 250-475 m. Radiocarbon was measured in individual rings isolated from sections of each colony, after dissolution of calcite. Each {Delta}{sup 14}C measurement was paired with a ring age determined by three amateur ring counters. The precision of ring counts averaged better than {+-} 2 years. Accurate reconstruction of 20th century bomb-radiocarbon shows that (1) the growth rings are formed annually, (2) the gorgonin is derived from surface particulate organic matter (POM) and (3) useful environmental data are recorded in the organic endoskeletons of deep-sea octocorals. These results support the use of Primnoa resedaeformis as a long-term, high resolution monitor of surface ocean conditions, particularly in temperate and boreal environments where proxy data are lacking.

The deep-sea gorgonian coral Primnoa spp. live in the Atlantic and Pacific Oceans at depths of 65 to 3200 m. They have an arborescent growth form with a skeletal axis composed of annual rings made from calcite and gorgonin. Lifespans may exceed several hundreds of years. It has been suggested that isotope profiles from the gorgonin fraction of the skeleton could be used to reconstruct long-term, annual-scale variations in surface productivity. We tested assumptions about the trophic level, intra- and inter-colony isotopic reproducibility, and preservation of isotopic signa- tures in a suite of modern and fossil specimens. Measurements of gorgonin δ 15 N indicate that Prim- noa spp. feed mainly on zooplankton and/or sinking particulate organic matter (POMsink), and not on suspended POM (POMsusp) or dissolved organic carbon (DOC). Gorgonin δ 13 C and δ 15 N in specimens from NE Pacific shelf waters, NW Atlantic slope waters, the Sea of Japan, and a South Pacific (South- ern Ocean sector) seamount were strongly correlated with surface apparent oxygen utilization (AOU; the best available measure of surface productivity), demonstrating coupling between skeletal iso- topic ratios and biophysical processes in surface water. Time-series isotopic profiles from different sections along the same colony, and different colonies inhabiting the same area were identical for δ 13 C, while δ 15 N profiles were less reproducible. Similarity in C:N, δ 13 C and δ 15 N between modern and fossil specimens suggest that isotopic signatures are preserved over millennial timescales. These results support the use of Primnoa spp. as historical recorders of surface water processes such as bio- logical productivity and the isotopic composition of source nutrients.

Singleton Swash on the South Carolina coast provides an extended record of storm events for this coast. We used experience gained by looking at storm traces detected as layers of offshore foraminifera intercalated with marsh sediments from a known storm in the area ( Hugo, which occurred in 1989) to detect storm horizons from the sediments that have been accumulating in Singleton Swash since 5700 yr B.P. We suggest here that the most intense storm activity occurred in the 0–1000 yr B.P. interval (six storms); only three occurred in the 1000–2000 yr B.P. interval and two in the 2000–3000 yr B.P. time interval (calibrated radiocarbon years). There was one giant storm in the pre–5000 yr B.P. interval; a sea-level oscillation in the 3500–5000 yr B.P. interval appears to have destroyed most records during that period. Previous work suggests that the position of the Bermuda (or Azores) High influences the direction of general storm paths for major North Atlantic hurricanes: a position of the Bermuda High farther to the south tends to force storms into the Gulf of Mexico, whereas a northern position allows them to track up the Atlantic Coast. Results here combined with results of other workers on the Gulf Coast suggest a more southern position for the Bermuda High, causing more storms on the Gulf Coast in the interval of 1000–3400 yr B.P. Conversely, a more northern position during the past 1000 yr is suggested to have contributed to higher frequencies of storms on the Atlantic Coast in that period. To test this hypothesis, modern records of the movement of the North Atlantic Oscillation (NAO, which controls the position of the Bermuda High) have been compared with historical records of hurricane tracks over the twentieth century. There does appear to be a strong correlation between the position of the NAO and the track the storms have pursued in modern times.

Key points All wetland ecosystems provide valuable services to local people and influence global carbon budgets; climate delimits four major ecosystems: arctic and subpolar marshes, temperate marshes, subtropical tidal wetlands and tropical mangrove swamps; wetlands worldwide have specialized plant forms adapted to physical extremes of soil salinity, instability and low oxygen; global biogeographic studies are the tools of wetlands biodiversity studies; primary regional differences in species composition reflect ancient paleogeographic changes; plate tectonics and icesheets isolated tropical ‘Old World’ from ‘New World’ biological provinces; coastal wetlands are azonal vegetation types highly influenced by soil conditions; differences in temperature and precipitation regimes shift the ecosystem boundaries north or south on different coasts of continents; seasonal variations in temperature–precipitation conditions drive subregional soil water salinity differences. In this chapter, general distinctions (both physical and biological features) of major latitudinal and climatic zones are outlined, so the reader can appreciate the broad similarities and dramatic differences in coastal wetlands across the globe (Chapters 7 to 11). We also look at the phytogeographical variations found on different coasts of the same continent and explain why the tropical floras of Atlantic and Pacific regions often are different, even within the same latitudinal range. Climate zones and coastal wetland ecosystems On a worldwide basis, there are four broad latitudinal zones of tidal wetlands (Figure 1.1). These world coastal wetland zones are: arctic and subpolar marshes; temperate zone marshes; subtropical marshes and mangroves; and tropical mangrove swamps. Each of these major ecosystems comprises a set of biological components interacting with their physical environment and providing characteristic wetland services (Figure 6.1) These services are defined by the Ramsar Convention as ‘the benefits people obtain from ecosystems, including provisions (food and water), regulating functions (buffering from floods and storms), nutrient cycling, and cultural needs (recreation, spiritual, and esthetic qualities)’. The vital services for human wellbeing include water purification and nitrate detoxification, climate regulation through sequestering and releasing of carbon in the biosphere, and mitigation of climate-driven sea level rise and storminess, which can result in erosion and devastating coastal floods (Millennium Ecosystem Assessment, 2005). Barbier et al . (2011) provide further details of the quality of estuarine and coastal ecosystem services and they estimate the financial losses to be expected from elimination of these services.