NUMERICAL SIMULATION OF TSUNAMI HAZARDS IN SOUTH ATLANTIC COAST: CASE OF THE CITY OF AGADIR – MOROCCO: PRELIMINARY RESULT

The coastal zone is a highly complex area because of its location at the interface between land and sea and as a preferred location for many forms of development. A mega tsunami from the Canary Islands will hit not only the Atlantic coasts of Morocco, but also Spain, Portugal, Great Britain and even reach US shores.A slight earthquake or possible volcanic eruption can trigger one of the most violent natural disasters in history. Indeed, according to Steven Ward and Simon Day (2001) the west flank of the Cumbre Vieja volcano, located on the island of Palma is unstable and could, as a result of a future eruption, collapse into the ocean. It would be in the worst scenario of a huge piece of 25 km long, 15 wide and 1,400 meters thick that would come off, a total of 500 cubic kilometers of land and rocks. This wave could reach 50 meters of height, once arrived on the Moroccan coasts. In this study, a numerical inundation and vulnerability models are used to identify the location and nature of current and future hazards and risk on the Moroccan coast to better understand the tsunami hazard and vulnerability along the Moroccan coast. We have worked on the correction of coastlines from satellite imagery on Google Earth and the digitization of bathymetric and topographic maps, in order to create digital elevation models (DEM). We have also studied the vulnerability assessment of the buildings by using the BTV model (Building Tsunami Vulnerability) such as a combination of tsunami inundation numerical modelling, field survey data and geographic information system.

Whimbrel populations differ in trans-atlantic pathways and cyclone encounters

Each year hundreds of millions of birds cross the Atlantic Ocean during the peak of tropical cyclone activity. The extent and consequences of migrant-storm interactions remain unknown. We tracked whimbrels from two populations (Mackenzie Delta; Hudson Bay) to examine overlap between migration routes and storm activity and both the frequency and consequence of storm encounters. Here we show that Mackenzie Delta and Hudson Bay whimbrels follow different routes across the ocean and experience dramatically different rates of storm encounters. Mackenzie Delta whimbrels departed North America from Atlantic Canada, made long ($$\bar{x}$$ x ¯ = 5440 ± 120.3 km) nonstop flights far out to sea that took several days ($$\bar{x}$$ x ¯ = 6.1 ± 0.18) to complete and encountered storms during 3 of 22 crossings. Hudson Bay whimbrels departed North America from the south Atlantic Coast, made shorter ($$\bar{x}$$ x ¯ = 3643 ± 196.2 km) nonstop flights across the Caribbean Basin that took less time ($$\bar{x}$$ x ¯ = 4.5 ± 0.29) to complete and encountered storms during 13 of 18 crossings. More than half of Hudson Bay storm encounters resulted in groundings on Caribbean islands. Grounded birds required longer ($$\bar{x}$$ x ¯ = 30.4 ± 5.32 days) to complete trans-Atlantic crossings and three were lost including 2 to hunters and 1 to a predator. One of the Mackenzie Delta whimbrels was lost at sea while crossing the Intertropical Convergence Zone. Whimbrels use two contrasting strategies to cross the Atlantic including (1) a long nonstop flight around the core of storm activity with a low likelihood of encountering storms but no safety net and (2) a shorter flight through the heart of Hurricane Alley with a high likelihood of encountering storms and a safety network of islands to use in the event of an encounter. Demographic consequences of storm encounters will likely play a role in the ongoing evolution of trans-Atlantic migration pathways as global temperatures continue to rise.

New records of red seaweeds to the coast of Ceará State, northeastern Brazil

ABSTRACT A recent floristic survey of Rhodophyta from Ceará State, Brazil (02º46'30''-07º52'15''S and 37º14'54''-41º24'45''W), revealed the occurrence of 113 species distributed into 14 orders, 28 families and 63 genera. Of these, 18 species belonging to seven orders are new records; some of them poorly described and illustrated in the literature or cited only checklists. Therefore, aiming to expand the taxonomic knowledge about these poorly known species, we present detailed descriptions, illustrations, and comments on related taxa. The occurrence of Ceratodictyon scoparium is confirmed for the South Atlantic coast. The male gametophytes of Dohrniella antillarum var. brasiliensis and tetrasporophytes of Gracilariopsis silvana are illustrated for the first time. Ceramium fujianum is a new addition to northeastern Brazil. Among the new records, Callithamnion corymbosum, Ceramium clarionense, C. fujianum and C. scoparium showed a significant expansion of their geographic distribution along the Brazilian coast. Most of the newly recorded species are filamentous, small-sized or tufted algae, highlighting the need for new collections to detect the presence of these components.

A NEW METHODOLOGY FOR EXTREME WAVES ANALYSIS BASED ON WEATHER-PATTERNS CLASSIFICATION METHODS

Extreme Value Analysis is usually based on the assumption that the data is independent and homogeneous. Historically the hypothesis of independence has received more attention than the hypothesis of homogeneity. The two most common ways of ensuring independence is to use annual maxima or peaks over threshold approaches. In wave and wind extreme analysis, the usual approaches to achieve homogeneous series have been to work to differentiate according to type of process generating the extreme value (e.g. differentiate between hurricanes and cyclones) and conduct directional analyzes. In this work an alternative approach is proposed, based on the use of cluster analysis methodologies to identify weather circulation patterns that results in extreme wave conditions. The proposed methodology is successfully applied to a case study in the Uruguayan South Atlantic coast. From the obtained results it seems that the proposed methodology is able to differentiate the data in homogenous subsets, not only in terms of the target variable (significant wave height) but also in terms of relevant covariables, like wave direction or sea level, and that the extreme value distribution of the whole data, obtained from the distributions fitted to each subset, is fairly insensitive to the number of weather patterns used in the analysis.

New morphological data and first description of gravid female of Cucullanus bagre Petter, 1974 (Seuratoidea: Cucullanidae) from Bagre bagre (Linnaeus, 1766) (Siluriformes: Ariidae) off Brazil

Cucullanus bagre Petter, 1974 (Cucullanidae) is redescribed based on the examination of newly collected material and the revaluation of type specimens, using light and for the first time scanning electron microscopy. Parasite specimens were collected from the intestine of the coco sea catfish Bagre bagre (Linnaeus) (Ariidae) off the South Atlantic coast, State of Rio de Janeiro, Brazil. Detailed morphological analysis revealed the presence of an unpaired papilla just anterior to the cloacal protrusion in male, that was overlooked in the original description. Descriptions of the adult female and eggs are provided for the first time; these gravid specimens have the general morphometry quite similar to that of juveniles. Additionally, detailed description and illustration of sclerotized plates present on the oesophastome is provided. The far posterior location of the excretory pore with thick-walled excretory duct, the conspicuous protrusions present on both anal and cloacal regions and the number and arrangement of caudal papillae in males are considered to be important diagnostic features for C. bagre. All the specimens from type material were together in one vial and not separated in two vials as stated in the original description, making it impossible to determine which is the holotype, allotype or paratypes. This is the first report of C. bagre in Brazil, which expands its geographical distribution to South Atlantic waters.

Occurrence of Magellanic Penguins along the Northeast Brazilian Coast during 2008 Austral Winter

During the austral winter of 2008, thousands of penguins traveled to low latitudes along the South Atlantic coast of South America. The atmospheric and oceanic conditions from April to July 2008 may account for the penguins' unusual geographic distribution. During that period, South Atlantic coastal waters were cooler; the wind anomalies had northward and onshore components; the ocean's coastal region presented northward currents that favored the penguins to travel toward lower latitudes. This anomalous climate regime resulted from extreme meteorological frontal systems that occurred mainly during June 2008. Three consecutive extreme midlatitude cyclones produced strong wind shear that resulted in the northward oceanic flow along the South American eastern shoreline favoring the penguins to be spotted in northern tropical waters.