Atlantic Coastline Research Articles

Anthropogenic Stressors on Mangrove Ecosystem and the Emergence of Mangrove Refugia on Parts of the Eastern Atlantic Coastline of Cameroon

The Atlantic coastline that adjoins Mount Cameroon is facing an ecological crisis as its mangrove ecosystem is progressively being depleted. Main stressors relate to inherent human activities notably; uncontrolled mangrove extraction for fuel, the creation of touristic/recreational sites, settlement expansion and agricultural development. As a corollary, the two dominant species of mangrove-Avicennia germinans and Rhizophora racemosa that once flourished over a large area now appear in refugia particularly in the south western coastline of Fako Division. In this region, thirty eight mangrove refugia were identified. Their mean altitudinal location is 11m above sea level as they range from five to nineteen metres. The degradation of the mangrove is accompanied by a savanisation process. In order to enhance the ecological resilience and sustainability of the mangroves in the region, a simple management plan has been developed based on the concept of close area management. This plan, groups the mangroves into six principal lots wherein, each of them calls for a particular management system. Consequently, zonation, sensitization program and the creation of a participatory management plan to mention but these will enhance sustainable growth and exploitation of mangroves along the coastline of Cameroon.

Determining the use of Late Archaic shell rings using lithic data: “ceremonial villages” and the importance of stone

ABSTRACTLate Archaic shell rings have been the focus of archaeological research for decades, yet their history, use, and function are debated. Relying on an evidentiary line rarely used in shell ring studies – the analysis of stone tools and debitage – we test prevailing theories and find that models describing the rings as circular dams intended to hold freshwater are incorrect. Instead, by tracing the origins of stone and its distribution within two shell rings on St. Catherines Island, Georgia, we posit that shell rings were places of both daily residence and intermittent gatherings. Because they have proven useful in interpreting the St. Catherines Island shell rings, we suggest archaeologists shift their sampling and recovery techniques so that representative lithic assemblages can be attained from other rings, thereby providing a better understanding of ring-builders and the Late Archaic occupation of the South Atlantic coastline.

The intertidal zones of the South Atlantic Bight and their local and regional influence on astronomical tides

Astronomical tides in the South Atlantic Bight are simulated with a fine-resolution (down to ∼10 m), shallow-water equations, finite element model that fully represents the contiguous geometry of the system, including the: width- and depth-variable continental shelf; inlet-punctuated coastline; and riverine and intertidal character of the estuaries. Tidal levels are analyzed for the entirety of the South Atlantic Bight which produces highly detailed maps (resolution of 10–100 m) of tidal datums (MLW—mean low water, MHW—mean high water) throughout the estuarine rivers and intertidal zones. Model skill (performance) when evaluated over 142 gaging stations is R2 = 92% for tidal datums (MLW and MHW) and less than 10% error for the full astronomical tide signal inside the estuaries, and within 0.01 m s–1 error for M2 shelf velocities. Tidal analysis reveals a sensitivity of the M2-resonant shelf circulation in the South Atlantic Bight with respect to the tidal inlets, estuarine rivers and intertidal zones, primarily from the Florida/Georgia border to Winyah Bay (South Carolina). The inlets generate an ‘openness’ the South Atlantic Bight coastline, but more important are the geometric-dynamic influences of the estuarine rivers (the cause-effect being enhanced resonance due to extended effective shelf width) and intertidal zones (the cause-effect being tidal decay due to energy dissipation). The riverine and intertidal features of the coastline subtly change the mode of tidal propagation over the continental shelf. Dynamically, the standing wave behavior (resonance) of astronomical tides in the South Atlantic Bight is a function of the shelf and coastline geometries. Modeling and assessment of coastal and shelf circulation should consider the domain as a continuum, including high-resolution definition of the coast's estuaries and intertidal zones.

Effects of bioturbation on the erodibility of cohesive versus non-cohesive sediments along a current-velocity gradient: A case study on cockles

Soft-bottom bioturbators are ecosystem engineers in the sense that they can have considerable effects on sediment erodibility and resuspension. The common cockle Cerastoderma edule is a bioturbating filter feeder that is widespread along the European Atlantic coastline. Its presence and activity can decrease sediment erosion thresholds in cohesive sediments but little is known about its effect on non-cohesive sediments. Using controlled annular flume experiments, we investigated the relative effects of different cockle densities on sediment resuspension in cohesive vs. non-cohesive sediments by assessing the following: (i) the mud and sand burrowing behavior of cockles, (ii) critical erosion thresholds, (iii) the mass of eroded sediment and (iv) erosion rates. Our results show that cockles were more active in non-cohesive sediment compared with cohesive sediment. Despite their lower activity, the presence of cockles in cohesive sediment increased sediment erodibility by reducing the critical erosion threshold (Ucrit) and increasing both the mass of eroded sediment and erosion rate. In contrast, cockles had no effect on erodibility in non-cohesive sediment, especially on the eroded sediment mass and erosion rate. The mass eroded was not significantly different between cohesive and non-cohesive sediments when cockles were present. Our experiments show that the increased erodibility of cohesive sediment due to the bioturbation by cockles is density dependent: higher cockle density results in stronger effects on erodibility. Moreover, this increase in cohesive sediment erosion due to cockle bioturbation was positively correlated with current velocity. In contrast, the erosion of non-cohesive sediment only depended on the current stress and was unaffected by cockle density. Considering the high abundance of C. edule, its widespread distribution and its extensive activities, the results of this study could be widely applicable to intertidal mud flats around the world.

A benevolent invader?

Ecology Plant and animal species introduced into non-native localities by humans sometimes become invasive, often with damaging ecological and economic consequences. However, Ramus et al. report an unusual case where an invasive species can be beneficial. Gracilaria vermiculophylla is a seaweed from the West Pacific that has been introduced to North Atlantic coastlines, where it has become invasive. In experimental manipulations of its abundance in North Carolina, USA, the seaweed enhanced an array of ecosystem functions by assuming the role of a “foundation” species that provides habitat for others. Benefits accrued to the abundance and species richness of gastropods and crustaceans and, through the attenuation of water flow, to coastal protection. Hence, toleration rather than eradication may be a pragmatic management strategy in this case. ![Figure][1] An invasive West Pacific seaweed proves protective on the U.S. eastern seaboard. PHOTO: LARS BRAMMER NEJRUP/NOBANIS, [HTTP://WWW.NOBANIS.ORG][2] Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1700353114 (2017). [1]: pending:yes [2]: http://WWW.NOBANIS.ORG

Fatty acid compositions associated with high-light tolerance in the intertidal rhodophytes Mastocarpus stellatus and Chondrus crispus

The rhodophytes Mastocarpus stellatus and Chondrus crispus occupy the lower intertidal zone of rocky shores along North Atlantic coastlines, with C. crispus generally occurring slightly deeper. Consequently, M. stellatus is exposed to more variable environmental conditions, related to a generally higher stress tolerance of this species. In order to extend our understanding of seasonal modulation of stress tolerance, we subjected local populations of M. stellatus and C. crispus from Helgoland, North Sea, to short-term high-light stress experiments over the course of a year (October 2011, March, May and August 2012). Biochemical analyses (pigments, antioxidants, total lipids, fatty acid compositions) allowed to reveal mechanisms behind modulated high-light tolerances. Overall, C. crispus was particularly more susceptible to high-light at higher water temperatures (October 2011 and August 2012). Furthermore, species-specific differences in antioxidants, total lipid levels and the shorter-chain/longer-chain fatty acid ratio (C14 + C16/C18 + C20) were detected, which may enhance the tolerance to high-light and other abiotic stress factors in M. stellatus, so that this species is more competitive in the highly variable upper intertidal zone compared to C. crispus. Since the high-light tolerance in C. crispus seemed to be affected by water temperature, interactions between both species may be impacted in the future by rising mean annual sea surface temperature around the island of Helgoland.

Spatial Variation of Sea Level Rise at Atlantic and Mediterranean Coastline of Europe

The inundation impact of sea level rise (SLR) is critical, since coastal regions of Europe house important critical infrastructures and large population centers. According to International Panel on Climate Change (IPCC) studies, the analysis of the SLR problem is complicated. Beyond the reported complexities involved in the analysis of this phenomenon, the expected spatial variability of SLR in oceans further complicates this analysis. Spatial variability of SLR in oceans is both observed and also expected, according to IPCC studies. Estimation of spatial variation of SLR in oceans is necessary to identify the level of potential threats that may impact different coastline regions. Identification of geographic patterns of SLR based on local coastal data has been reported in the literature. Unfortunately, these estimates cannot be used in predictive analysis over a century. Thus, the solution of this problem using mathematical models is the other alternative that can be employed. Modeling solutions to this problem is currently in its infancy, and further studies in this field are needed. In this study, a methodology developed by the authors is used to estimate the SLR for the Atlantic and the Mediterranean coastline of Europe that also includes the other oceans. This effort utilizes the dynamic system model (DSM) with spatial analysis capability (S-DSM) to predict the regional sea level change. Results obtained provide consistent assessment of spatial variability of SLR pattern in oceans as well as the temperature changes over the 21st century. This approach may also be used in other coastal regions to aid management decision in a timely manner.

Investigating added value of regional climate modeling in North American winter storm track simulations

Extratropical Cyclone (EC) characteristics depend on a combination of large-scale factors and regional processes. However, the latter are considered to be poorly represented in global climate models (GCMs), partly because their resolution is too coarse. This paper describes a framework using possibilities given by regional climate models (RCMs) to gain insight into storm activity during winter over North America (NA). Recent past climate period (1981–2005) is considered to assess EC activity over NA using the NCEP regional reanalysis (NARR) as a reference, along with the European reanalysis ERA-Interim (ERAI) and two CMIP5 GCMs used to drive the Canadian Regional Climate Model—version 5 (CRCM5) and the corresponding regional-scale simulations. While ERAI and GCM simulations show basic agreement with NARR in terms of climatological storm track patterns, detailed bias analyses show that, on the one hand, ERAI presents statistically significant positive biases in terms of EC genesis and therefore occurrence while capturing their intensity fairly well. On the other hand, GCMs present large negative intensity biases in the overall NA domain and particularly over NA eastern coast. In addition, storm occurrence over the northwestern topographic regions is highly overestimated. When the CRCM5 is driven by ERAI, no significant skill deterioration arises and, more importantly, all storm characteristics near areas with marked relief and over regions with large water masses are significantly improved with respect to ERAI. Conversely, in GCM-driven simulations, the added value contributed by CRCM5 is less prominent and systematic, except over western NA areas with high topography and over the Western Atlantic coastlines where the most frequent and intense ECs are located. Despite this significant added-value on seasonal-mean characteristics, a caveat is raised on the RCM ability to handle storm temporal ‘seriality’, as a measure of their temporal variability at a given location. In fact, the driving models induce some significant footprints on the RCM skill to reproduce the intra-seasonal pattern of storm activity.

Changes in the US hurricane disaster landscape: the relationship between risk and exposure

This research appraises how residential built environment growth influences coastal exposure and how this component of societal vulnerability contributes to tropical cyclone impact and disaster potential. Historical housing unit data and future demographic projections from a high-resolution, spatial allocation model illustrate that the area within 50 km of the US Atlantic and Gulf Coastlines has the greatest housing unit density of any physiographic region in the USA, with residential development in this region outpacing non-coastal areas. Tropical cyclone exposure for six at-risk metropolitan statistical areas (MSAs) along the US Atlantic and Gulf Coasts are assessed. All six MSAs evaluated are distinct in their development character, yet all experienced significant growth from 1940 through the contemporary period; projections from the model under various socioeconomic pathways reveal that this growth is anticipated to continue during the twenty-first century. Using a worst-case scenario framework, the historical and future residential data for the six MSAs are intersected with synthetic hurricane wind swaths generated from contemporary landfalling events. The New York City MSA contains the greatest residential built environment exposure, but Miami is the most rapidly changing MSA and has the greatest potential for hurricane disaster occurrence based on the juxtaposition of climatological risk and exposure. A disaster potential metric illustrates that all six MSAs will experience significant increases in disaster probability during the twenty-first century. This analysis facilitates a detailed spatiotemporal assessment of US coastal region vulnerability, providing decision makers with information that may be used to evaluate the potential for tropical cyclone disasters, mitigate tropical cyclone hazard impacts, and build community resilience for these and other hazards in the face of environmental and societal change.

Population structure of Purple Sandpipers (Calidris maritima) as revealed by mitochondrial DNA and microsatellites.

The Purple Sandpiper (Calidris maritima) is a medium‐sized shorebird that breeds in the Arctic and winters along northern Atlantic coastlines. Migration routes and affiliations between breeding grounds and wintering grounds are incompletely understood. Some populations appear to be declining, and future management policies for this species will benefit from understanding their migration patterns. This study used two mitochondrial DNA markers and 10 microsatellite loci to analyze current population structure and historical demographic trends. Samples were obtained from breeding locations in Nunavut (Canada), Iceland, and Svalbard (Norway) and from wintering locations along the coast of Maine (USA), Nova Scotia, New Brunswick, and Newfoundland (Canada), and Scotland (UK). Mitochondrial haplotypes displayed low genetic diversity, and a shallow phylogeny indicating recent divergence. With the exception of the two Canadian breeding populations from Nunavut, there was significant genetic differentiation among samples from all breeding locations; however, none of the breeding populations was a monophyletic group. We also found differentiation between both Iceland and Svalbard breeding populations and North American wintering populations. This pattern of divergence is consistent with a previously proposed migratory pathway between Canadian breeding locations and wintering grounds in the United Kingdom, but argues against migration between breeding grounds in Iceland and Svalbard and wintering grounds in North America. Breeding birds from Svalbard also showed a genetic signature intermediate between Canadian breeders and Icelandic breeders. Our results extend current knowledge of Purple Sandpiper population genetic structure and present new information regarding migration routes to wintering grounds in North America.

Potential environmental drivers of a regional blue mussel mass mortality event (winter of 2014, Breton Sound, France)

In the context of global change, increasing mariculture production has raised particular concerns regarding its environmental impact and sustainability. Molluscs and particularly blue mussel account for a significant part of this total production. Although blue mussels are considered to be pretty resilient to environmental disturbances, we report in this study an unprecedented mussel mortality event that occurred during the winter of 2014 in the Breton Sound. 9000metrictonnes of mussels were lost and mortality rates up to 100% were recorded at some farming areas. Through a coupling approach, the present work aims to better understand the potential environmental drivers associated with those mortalities. Firstly, we analysed long-term in situ and satellite data from environmental monitoring networks (available since 1998) to characterize the variability of seawater masses of the sound during the winter of 2014. Secondly, we used modelling simulations to study the possible relationship between seawater hydrodynamics and observed spatio-temporal patterns of mussel mortalities. From January to April 2014 at the long-line culture site where mortalities started, seawater temperatures ranged from 8.3 to 13.3°C (10.2±0.8°C). Salinity and turbidity values showed successive and short drops (below 16; 29.3±2.3) and numerous peaks (above 70 NTU; 17.4±13.4 NTU) respectively. Winter conditions of 2014 were encountered along the entire French Atlantic coastline and linked to the sixth highest positive North Atlantic Oscillation (NAO+) index recorded since 1865. These particular environmental variations characterized the winter of 2014 but also others whereas no comparable mussel mortality rates were reported. Exact causes of the 2014 mortality event are still unknown but we showed these environmental variations could not alone be responsible. These have likely affected the sensitivity of the blue mussel populations that were already weakened by early spawning. Meanwhile, these may have facilitated the apparition of a pathogenic strain of Vibrio splendidus isolated on moribund mussels at that time. Our modelling simulations suggested that this pathogenic strain could spread through hydrodynamic patterns and drive the observed mussel mortalities. If this pathogenic strain recurs in future years, particularly with the added stress associated with climate change, mussel mass mortality events may exceed the resilience of this species.

Phylogeographic insights into Artemisia crithmifolia (Asteraceae) reveal several areas of the Iberian Atlantic coast as refugia for genetic diversity

The study of fragmentation processes should be tackled using different approaches, in order to obtain solid and robust evidence that could help in identifying potential barriers and threats for species. In this study, we have evaluated the spatial fragmentation patterns in Artemisia crithmifolia (Asteraceae) along its current distribution along the Atlantic coastlines of Europe, from Portugal to the Netherlands and the UK. Niche modelling analyses considering current and past climatic conditions, combined with plastid markers, have been used to evaluate the disconnected distribution pattern of the species, genetic flow between populations and habitat suitability for present and past populations. Plastid markers showed very low variability, while suggesting that the westernmost populations from the Atlantic coast of the Iberian Peninsula are partially genetically isolated, due to the existence of a potential barrier for gene flow on the northern Spanish coast. However, niche models identify this area as a potential habitat for the species, even during the last glacial maximum (20,000 years ago). The combination of both techniques allows identification of potential refugia for the species, highlighting the most likely recolonisation routes and distribution patterns which resulted in the overall low levels of genetic diversity. Anthropogenic activities (urban sprawl, beach expansions, etc.) are most likely behind local extinctions, thus preventing the establishment and expansion of new populations.

The Planisphere of Juan de la Cosa (1500): The First Padrón Real or the Last of Its Kind?

The chart drawn by Juan de la Cosa in 1500 contains an important innovation that distinguishes this planisphere from the other nautical charts produced at the time: the depiction of the equator and the Tropic of Cancer. This is a sign that astronomically observed latitudes may have been incorporated into the representation. In order to investigate such a possibility, the results of a cartometric analysis focused on the representation of the Atlantic and Indian Ocean coastlines are presented and discussed in this article, and several revealing conclusions will be drawn from the resulting analysis.

Nuevas investigaciones arqueológicas subacuáticas en el área de La Caleta (Cádiz, España). Estudio de las evidencias de época púnica (siglos VI-III a.C)

La zona costera de La Caleta, en el extremo noroccidental de la isla de Cádiz, constituye desde los inicios de la investigación subacuática en la bahía gaditana uno de los principales escenarios de investigación a partir tanto de destacados hallazgos puntuales como de actuaciones geo-arqueológicas científicas. La interpretación de este conjunto de datos ha sido muy dispar, tanto como el grado de publicación de las campañas arqueológicas realizadas, y la información disponible se encuentra actualmente muy dispersa. Asimismo, algunas cuestiones como la aparición de materiales que han sido tradicionalmente considerados como evidencias cultuales (anforillas, quemaperfumes, terracotas, etc.) y su relación con los templos citados en las fuentes literarias clásicas han focalizado hasta ahora la mayor parte de estudios, dejando en segundo plano temas de gran importancia histórica. Se propone en estas páginas una revisión panorámica de la documentación generada por hallazgos casuales y campañas precedentes, conjugando estas evidencias con las proporcionadas por actuaciones sistemáticas desarrolladas recientemente (2008-2010), atendiendo especialmente a los restos materiales relativos a la etapa púnica (siglos VI-III a.C.). Adicionalmente, se plantearán algunas nuevas propuestas de interpretación de La Caleta en este periodo, acerca de su configuración geo-arqueológica y su relación con actividades portuarias, comerciales, cultuales o funerarias prerromanas.

Movement patterns of striped bass (Morone saxatilis) in a tidal coastal embayment in New England

Striped bass (Morone saxatilis) are important in commercial and recreational fisheries along the western Atlantic coastline. Although there is a good understanding of their seasonal migration patterns, less is known about the short-term movements of striped bass once they have reached New England coastal embayments during the summer months. Movement patterns were assessed by tagging 35 striped bass (38.5–80.5cm TL) with acoustic transmitters and tracking them within a fixed array (n=34 receivers) in Plymouth, Kingston, Duxbury (PKD) Bay, MA. The majority of tagged striped bass took up residency within PKD Bay for the summer months. Large juvenile through sub-adult (21–46cm) and adult bass (>46cm) remained residents of PKD Bay for periods of 6–75days and appear to use the estuary as a vital summer foraging area before emigrating from the bay for their southward migration. Changes in activity space estimates were significant over the course of the season and increased with water temperature. There was a general increase of activity space preceding emigration where presence of striped bass was significantly related to water temperature and photoperiod. Various environmental factors influence striped bass movement, and it is important to understand individual patterns and behavioral ecology to make the most educated management decisions.

Epigean Tenebrionids (Coleoptera: Tenebrionidae) from Leones and Tova-Tovita Islands (Chubut, Argentina) and Its Comparison with the Mainland Assemblage

The Parque Interjurisdiccional Marino Costero Patagonia Austral (PIMCPA) protects over 180 km of Patagonian Atlantic coastline of northern San Jorge gulf, including an archipelago that comprises more than 39 islands. In this work, we studied the darkling beetles (Coleoptera: Tenebrionidae) of the two largest islands in the PIMCPA archipelago: Leones and Tova-Tovita. Tenebrionids are reported for first time in these islands, in addition, we described their species assemblage. Likewise, a comparison between the islands and the mainland was also performed. The GLM, MDS, ANOSIM and PCA methods were employed. Islands share the same tenebrionid species assemblage but they differ from that displayed on the mainland. Considering both islands as a whole, the insular assemblage shows lower species richness and diversity than those seen in the mainland. We identified eight species in the islands which belong to eight genera and four tribes. We also found that six of these species were shared among islands. Psectrascelis punctipennis Kulzer was exclusively recorded from the Tova-Tovita, while Platesthes kuscheli Kulzer from the Leones island. The island assemblage is mainly composed of nocturnal or crepuscular species [including Praocis (Hemipraocis) sellata bergi Burmeister, Patagonogenius quadricollis (Fairmaire), Emmallodera crenaticostata crenaticostata Blanchard and Scotobius akidioides akidioides Waterhouse], while several diurnal species of Nyctelia Berthold are the most common and diverse darkling beetles among mainland fauna. Additionally, we discuss the effects of the mainland distance, paleoclimate, and the origin of insular assemblages. Finally, other insular implications of tenebrionid beetles are discussed.

Fish Names Variability Traces the Geo-Historical Dynamics of Moroccan Fishermen Communities

INTRODUCTIONThe knowledge related to fish names is an integral part of being a fisherman and considered as a proof of competence within fishermen communities. This local knowledge is designated as folk taxonomy, and is in some ways predictably similar to the scientific (Linnaean) naming system (Berkes et al. 2001; Berlin 1992; Jernudd and Thuan 1984). Such knowledge is local in scope and thus highly variable by geographic region, language, and ethnic group depending on local culture, biodiversity patterns, and fishing practices. It is also assumed to vary in time. Due to widespread anthropogenic pressure causing the collapse of fishing stocks and local extinctions of species, young fishermen will have had little probability to meet as many species and in such numbers as have their predecessors. This folk taxonomy knowledge in its different dimensions is intimately associated with Local Ecological Knowledge (LEK), and its description is often a prerequisite to gather local biological and ecological knowledge (Berkes et al. 2001; Eugene Hunn 2011; Freire and Pauly 2003; Haggan et al. 2007). The relevance of ecological information is likely to be anecdotal if the accuracy of taxonomic identification is not guaranteed (Albuquerque et al. 2014). Local ecological knowledge has become an essential source of information for conservation ecology (Ruddle and Davis 2013), especially in data-poor ecosystems.Morocco presents an interesting case for examining variability in fish naming due to great diversity of species, as well as long and varied sociolinguistic traditions. Bordered by both Mediterranean and Atlantic coastlines of Northwestern Africa, Morocco is the center of the transition zone between temperate and tropical waters, populated with diverse species communities (Masski and Tai 2014; Tai et al. 2013). For bony fish alone, FishBase (Froese and Pauly 2011) lists more than 766 species for Morocco. Fishing activity is widespread along the Moroccan coast, involving culturally diverse populations. Cultural diversity, an additional variable to consider, has its origin in the geopolitical situation of the country, which has always put indigenous people in close interaction with the people of Europe, Africa, and Arabia.What is considered by one as a diversity of local knowledge is seen by others as a variability in seafood labelling and represents a central issue in trade control and regulation, and in fisheries science and conservation (Fraser 2012; Leunda Urretabizkaia et al. 2009). In developing countries, where the adoption of a standard for naming fish is uncommon, vernacular (folk) and common names are also used in national fisheries statistics systems (Previero et al. 2013). Due to the high variability in folk taxonomy, the same fish species can be named differently in different regions, and one name can be attributed to different fish species (Berlin 1973, 1992). Furthermore, the use of fishery statistics databases for scientific purposes is therefore restricted to well-identified species, which impedes fisheries management procedures (Kifani et al. 2008). The usual answer to such a situation is the adoption of a standard, which is the goal of the Moroccan fisheries management agencies.The success of the targeted standardization is, in our opinion, dependent on the strength of reflection and research previously conducted. Thus, and far from wanting to carry out a comprehensive inventory of vernacular names, the present study aims to 1) build correspondence lists between folk and scientific names for a set of species in different locations along the Moroccan coast and, on this basis, 2) to analyze the structure and variability of the Moroccan folk taxonomic system. We hope that the results from our study will help to improve the use of folk taxonomy in formal management procedures, facilitate local ecological knowledge gatherings, and clarify the view for the ways to achieve a standardization process. …

Biological effects of gold mine tailings on the intertidal marine environment in Nova Scotia, Canada

From 1861 to the 1940s, gold was produced from 64 mining districts in Nova Scotia, where mercury amalgamation was the dominant method for the extraction of gold from ore until the 1880s. As a result, wastes (tailings) from the milling process were contaminated by mercury and were high in naturally occurring arsenic. In 2004 and 2005, sediments, water and mollusc tissues were collected from 29 sampling stations at nine former gold mining areas along the Atlantic coastline and were analysed for arsenic and mercury. The resulting data were compared with environmental quality guidelines. Samples indicated high potential risk of adverse effects in the intertidal environments of Seal Harbour, Wine Harbour and Harrigan Cove. Arsenic in Seal Harbour was bioavailable, resulting in high concentrations of arsenic in soft-shell clam tissues. Mercury concentrations in tissues were below guidelines. This paper presents results of the sampling programs and implications of these findings.

Surface water subduction during a downwelling event in a semienclosed bay

AbstractThe Ría de Vigo is a bay strongly influenced by upwelling‐downwelling cycles along the adjacent coast of NW Iberia. Moored and ship‐board observations during September 2006 showed that subduction, initially associated with an estuarine circulation, strengthened when a strong downwelling circulation, resulting from northward wind over the coastal ocean, was generated in the outer Ría causing ambient waters to be advected outward in the lower layer. Incoming surface waters confined the estuarine circulation to the shallow interior and displaced isopleths downward through the water column at ∼10 m d−1. As the estuarine circulation retreated inward, strong flow convergence developed between middle and inner ria in the layer above 15 m, while divergence developed beneath. The convergence increased through the period of downwelling‐favorable wind at a rate consistent with the observed isopleth displacement velocities. The coefficient of turbulent diffusion Kt, from a microstructure profiler, indicated that mixing was strong in the estuarine circulation and subsequently in the downwelling zone, where localized instabilities and temperature‐salinity inversions were observed. During the downwelling, concentrations of phytoplankton, including potentially harmful species, increased, especially in the middle and inner ria, as a result of inward advection, subduction, and the ability of the dinoflagellates to maintain their position in the water column by swimming. In the course of the 5 day event, the water mass of all but the innermost Ría was flushed completely and replaced by waters originating in the coastally trapped poleward flow along the Atlantic coastline.

Exploring hurricane wind speed along US Atlantic coast in warming climate and effects on predictions of structural damage and intervention costs

This paper proposes a methodology for the rational assessment of lifetime costs on tall buildings due to hurricane-induced damage along the US Atlantic coastline accounting for plausible future warming climate scenarios. The hurricane simulation is based on Vickery’s empirical model. Initially, regression errors in Vickery’s model are discussed; some adjustments are proposed to enable hurricane simulation in future climates. After verification of the hurricane model’s ability to simulate the results of the United States historical hurricane database, simulation of hurricane activity in future climates is examined. The warming climate scenarios are reproduced from the results of the community earth system model, maintained by the National Center for Atmospheric Research (NCAR). Three different future climate scenarios, RCP2.6, RCP4.5 and RCP8.5, are considered. The influence of warming climate on two quantities, relevant to wind engineering, is examined: hurricane frequency and hurricane intensity. It is found that, in a warming climate environment, the hurricane frequency and hurricane intensity may vary depending on the RCP scenario. Therefore, the probability distribution of the wind speed in hurricane-prone areas of the United States, both coastal and interior areas, will also be influenced by the RCPs.The numerical methodology for computing wind speed probability distribution in a future warming climate, influenced by the various RCP scenarios, is subsequently coupled with an existing approach for structural performance analysis against wind hazards to predict the indirect effect of future warming climate on the structural intervention costs (i.e. repair costs), induced by the damaging winds. A 180-m tall benchmark building, located in Miami (Florida, USA), is used as one example of application in conjunction with a series of structural fragility curves, derived from a recent study for the same structure. The evaluation of lifetime intervention costs is later expanded to demonstrate the ability of the proposed methodology to predict hurricane wind damage, if the location of the structure is moved to several other cities along the Atlantic coast of the United States.