Western Coast Of Africa Research Articles

The recent colonization of south Brazil by the Azores chromis Chromis limbata.

The damselfish Chromis limbata is native to the Macaronesian Archipelagos (Azores, Madeira and Canaries) and the western coast of Africa between Senegal and Angola. During the austral summers of 2008 and 2009 the species was recorded for the first time in the south-western Atlantic Ocean around Campeche and Xavier Islands, in Florianópolis, Santa Catarina State, Brazil. Here, the progression of C. limbata in southern Brazilian waters is described using visual counts and genetic surveys and changes in the density of the native congener Chromis multilineata were also investigated. Underwater visual censuses of both Chromis species were carried out from 2009 to 2014. Chromis limbata tissue samples were collected and the mtDNA control region was sequenced and compared with mtDNA haplotypes from the natural range to confirm species identity, compare genetic diversity and to infer connectivity between newly established Brazilian populations. The Brazilian population of C. limbata increased significantly over the past 5 years and the effect on C. multilineata is still an open question, longer time-series data will be necessary to clarify possible interactions. The molecular analyses confirmed species identity, revealed strong haplotype connectivity among Brazilian study sites and showed a low genetic diversity in Brazil when compared with the native populations, suggesting few individuals started the invasion. Four hypotheses could explain this colonizing event: C. limbata was released by aquarium fish keepers; larvae or juveniles were transported via ship ballast water; the species has rafted alongside oil rigs; they crossed the Atlantic Ocean through normal larval dispersal or naturally rafting alongside drifting objects. The rafting hypotheses are favoured, but all four possibilities are plausible and could have happened in combination.

New records of king crabs (Decapoda, Anomura, Lithodidae) from southern Brazil

Until now only six species of lithodids have been found occasionally in the Brazilian coast. Most king crabs are accidentally caught during fisheries targeting other species. Herein we report new records for Lithodes confundens and Neolithodes aff. asperrimus from the south of Brazil, from the states of Rio Grande do Sul and Santa Catarina, respectively. Lithodes confundens is found in the western Atlantic with a previous northern limit in the Province of Buenos Aires, Argentina. Neolithodes aff. asperrimus is known to occur only along the western coast of Africa in the eastern Atlantic and this is the first record of the species in the western Atlantic.

NASA’s Hurricane and Severe Storm Sentinel (HS3) Investigation

Abstract The National Aeronautics and Space Administration’s (NASA) Hurricane and Severe Storm Sentinel (HS3) investigation was a multiyear field campaign designed to improve understanding of the physical processes that control hurricane formation and intensity change, specifically the relative roles of environmental and inner-core processes. Funded as part of NASA’s Earth Venture program, HS3 conducted 5-week campaigns during the hurricane seasons of 2012–14 using the NASA Global Hawk aircraft, along with a second Global Hawk in 2013 and a WB-57f aircraft in 2014. Flying from a base at Wallops Island, Virginia, the Global Hawk could be on station over storms for up to 18 h off the East Coast of the United States and up to about 6 h off the western coast of Africa. Over the 3 years, HS3 flew 21 missions over nine named storms, along with flights over two nondeveloping systems and several Saharan air layer (SAL) outbreaks. This article summarizes the HS3 experiment, the missions flown, and some preliminary findings related to the rapid intensification and outflow structure of Hurricane Edouard (2014) and the interaction of Hurricane Nadine (2012) with the SAL.

CABO VERDE: GEOPOLÍTICA E PROJEÇÃO DE UM PEQUENO ESTADO INSULAR NA ÁFRICA OCIDENTAL

The article seeks to understand the geopolitics of Cape Verde in the context of West Africa, and its projection as a small island State. The central argument is that Cape Verde needs to make pragmatic use of the Western African coast region for its regional projection. The article focus on a qualitative methodological analysis, based on an interpretative approach and a bibliographical revision in order to address the international phenomena that configure the Cape Verdean geopolitics in West Africa.

The western coast of Africa in Ptolemy's <i>Geography</i> and the location of his prime meridian

Abstract. A controversial question concerning ancient geography is the location of the prime meridian which underlies the position data in Ptolemy's Geography and runs through the Fortunate Islands. An answer to this question is derived by means of a localisation of the places given by Ptolemy at the African western coast, i.e. in Mauritania Tingitana and Libya Interior, whose modern identifications are often uncertain or unknown. The origination of Ptolemy's positions from the distance data of seafarings is considered. A comparison of his data with distances reported by Pliny yields a satisfactory agreement. The localisation of Ptolemy's places is based on distances derived from Ptolemy's coordinates and partly on further information by ancient authors. Through it previous identifications are confirmed and new identifications are found. It shows that the Fortunate Islands correspond to several eastern islands of the Canary Islands. Explanations are given for the errors of Ptolemy's position data. A likely error by Ptolemy barely considered is his repetition of a part of Mauritania Tingitana in his description of Libya Interior. The existence of this repetition is confirmed by an adjustment of a transformation between the positions of the duplicated places and a statistical test of the arranged model. A comparison of longitudinal distances in different ancient sources reveals that the position of Ptolemy's prime meridian is based on distances given by Marinos and Eratosthenes.

The Influence of African Easterly Waves on Convection over Tropical Africa and the East Atlantic

Abstract Using data from the Tropical Rainfall Measuring Mission (TRMM), the modulation of convection by African easterly waves (AEWs) is investigated over regions of the east Atlantic and tropical Africa. To explain the modulation of convection, the large-scale environment (lift, moisture, conditional instability, and shear) is also examined as a function of AEW phase in each region. Over semiarid portions of tropical Africa, unconditional rain rates are greatest in the northerly phase of AEWs due to the strong adiabatic forcing for ascent. Along the Guinea Coast, the western coast of Africa, and over the east Atlantic—where forcing for ascent is weaker—rainfall is shifted toward the trough where the air is moist. Significant contrasts in the characteristics of convection as a function of AEW phase—comparable in magnitude to regional contrasts—are also observed. In all regions, large and high echo-top convective systems are more sensitive to AEW phase than small and low echo-top systems. In semiarid regions, deep convection and large high echo-top convective systems account for a large fraction of the rainfall in the ridge and northerlies. Stratiform and small low echo-top convective systems dominate in the trough and southerlies. Convective system height and conditional rain rates increase with conditional instability and system sizes may increase with shear. Over the east Atlantic, stratiform fractions and convective system sizes and echo-top heights are greatest in the trough while the ridge is dominated by shallow convection. This is primarily related to the presence of moist air in the trough and dry air in the ridge.

Review ofPugilinafrom the Atlantic, with Description of a New Species from Brazil (Neogastropoda, Melongenidae)

The anatomy of Brazilian and African specimens of Pugilina morio, a supposedly amphi-Atlantic species, is described in detail in this paper. Two different entities are recognised. The first is the true Pugilina morio, which is now restricted to the western African coast, from Senegal to Congo. The remaining species is Pugilina tupiniquim sp. n., described herein as the single Brazilian melongenid species known so far, distributed from the Caribbean to Brazil (Para to Santa Catarina states). The two species showed important anatomical discrepancies, and differ in the position of the tentacles, size of the neck, diameters of the aortas, diameter of the posterior oesophagus, and other features described below. A bursa copulatrix and rachidian teeth bearing a central cusp are both exclusive to P. morio.

In-Depth Review: The Formation of Candomblé: Vodun History and Ritual in Brazil, by Luis Nicolau Parés

The Atlantic slave trade extracted kidnapped populations from the entirety of the western African coast between what are now Senegal and Angola, as well as parts of the east African coast in what is now Mozambique. Western slave traders and buyers regularly classified their human merchandise in terms of the African region, coastal town, or commercial fortress from which they had embarked, or in terms of an ethnic group that presumably derived from that place. With such presumptions, ethnic groupings such as Congo, Angola, Carabalí, Ibo, Nagô, Lucumí, Mina, Arará, Koromantee, and so forth were called “nations.”

Regional fishery management organizations and large marine ecosystems

Regional fisheries management organizations (RFMOs) addressing the management of living marine resources have a long history, beginning in 1811 with the North Pacific Fur Seal Convention followed by the International Pacific Halibut Convention in 1924. Following the expansion of fisheries after WWII RFMOs proliferated and after the general acceptance of a 200 mile extended jurisdiction in the mid-1970s many more nations became involved. There are approximately 17 RFMOs, (depending on the definition of “management”) of the over 40 marine Regional Fisheries Bodies(RFBs) identified by FAO. The Large Marine Ecosystem (LME) approach has roots in the experience of the International Commission for the Conservation of Northwest Atlantic Fisheries (now defunct and replaced by the Northwest Atlantic Fisheries Organization (NAFO)) which pioneered ecosystem based fisheries management. The LME approach was fleshed out in the 1980s and initiated as both the Global Environment Facility (GEF) and country projects, beginning in the mid-1990s. LMEs have fisheries as a major component to be addressed under the LME five-module concept. As LME Programs enter the stage where they need to move to develop their governance responsibilities, the relationship with existing RFMOs is critical. This paper examines possibilities for this interaction with special attention to, but not exclusively, the Western coast of Africa. Possible inferences from the US east coast experience are also addressed, considering the Atlantic States Marine Fisheries Commission as a pseudo RFMO with the states assuming a role similar to countries.

Software package for reconstructing reflective properties of the Earth’s surface in the visible and UV ranges

A description of a software package for reconstructing the distribution of the reflection coefficient of the Earth’s surface, as well as procedures developed for a considerable reduction of the computation time, is presented. By an example of a test region in the western coast of Africa, a comparison has been performed for results obtained by the proposed algorithm, the algorithm of homogeneous correction, and the standard MOD09 NASA algorithm. The correlation coefficients of results for this test region are as follows: between the new algorithm and homogeneity correction algorithm, 0.999; between the new algorithm and the MOD09 algorithm, 0.984.

Individual consistency and sex differences in migration strategies of Scopoli’s shearwaters Calonectris diomedea despite year differences

Abstract Recently-developed capabilities for tracking the movements of individual birds over the course of a year or longer has provided increasing evidence for consistent individual differences in migration schedules and destinations. This raises questions about the relative importance of individual consistency versus flexibility in the evolution of migration strategies, and has implications for the ability of populations to respond to climatic change. Using geolocators, we tracked the migrations of Scopoli’s shearwaters Calonectris diomedea breeding in Linosa (Italy) across three years, and analysed timing and spatial aspects of their movements. Birds showed remarkable variation in their main wintering destination along the western coast of Africa. We found significant individual consistency in the total distance traveled, time spent in transit, and time that individuals spent in the wintering areas. We found extensive sex differences in scheduling, duration, distances and destinations of migratory journeys. We also found sex differences in the degree of individual consistency in aspects of migration behaviour. Despite strong evidence for individual consistency, which indicates that migration journeys from the same bird tended to be more similar than those of different birds, there remained substantial intra-individual variation between years. Indeed, we also found clear annual differences in departure dates, return dates, wintering period, the total distance traveled and return routes from wintering grounds back to the colony. These findings show that this population flexibly shifts migration schedules as well as routes between years in response to direct or indirect effects of heterogeneity in the environment, while maintaining consistent individual migration strategies.

Evolution at a different pace: distinctive phylogenetic patterns of cone snails from two ancient oceanic archipelagos.

Ancient oceanic archipelagos of similar geological age are expected to accrue comparable numbers of endemic lineages with identical life history strategies, especially if the islands exhibit analogous habitats. We tested this hypothesis using marine snails of the genus Conus from the Atlantic archipelagos of Cape Verde and Canary Islands. Together with Azores and Madeira, these archipelagos comprise the Macaronesia biogeographic region and differ remarkably in the diversity of this group. More than 50 endemic Conus species have been described from Cape Verde, whereas prior to this study, only two nonendemic species, including a putative species complex, were thought to occur in the Canary Islands. We combined molecular phylogenetic data and geometric morphometrics with bathymetric and paleoclimatic reconstructions to understand the contrasting diversification patterns found in these regions. Our results suggest that species diversity is even lower than previously thought in the Canary Islands, with the putative species complex corresponding to a single species, Conus guanche. One explanation for the enormous disparity in Conus diversity is that the amount of available habitat may differ, or may have differed in the past due to eustatic (global) sea level changes. Historical bathymetric data, however, indicated that sea level fluctuations since the Miocene have had a similar impact on the available habitat area in both Cape Verde and Canary archipelagos and therefore do not explain this disparity. We suggest that recurrent gene flow between the Canary Islands and West Africa, habitat losses due to intense volcanic activity in combination with unsuccessful colonization of new Conus species from more diverse regions, were all determinant in shaping diversity patterns within the Canarian archipelago. Worldwide Conus species diversity follows the well-established pattern of latitudinal increase of species richness from the poles towards the tropics. However, the eastern Atlantic revealed a striking pattern with two main peaks of Conus species richness in the subtropical area and decreasing diversities toward the tropical western African coast. A Random Forests model using 12 oceanographic variables suggested that sea surface temperature is the main determinant of Conus diversity either at continental scales (eastern Atlantic coast) or in a broader context (worldwide). Other factors such as availability of suitable habitat and reduced salinity due to the influx of large rivers in the tropical area also play an important role in shaping Conus diversity patterns in the western coast of Africa.

Unravelling migration routes and wintering grounds of European rollers using light-level geolocators

We used light-level geolocators to track the migratory journey of a globally near-threatened trans-Saharan migrant, the European roller Coracias garrulus, from its breeding grounds in Iberia to its wintering grounds in southern Africa. During autumn migration, birds followed the western African coast with lengthy stopovers within sub-Saharan countries before crossing the equatorial rainforests towards the wintering areas, mainly in Angola. Although based in only two tracked birds, comparison of our results with other studies suggests that western European rollers use distinct migration routes and stopover sites towards shared wintering grounds. Time spent in widely separated and ecologically disparate countries highlights the vulnerability of the species facing the cumulative risks of each area used along their journey.

“The United States of Africa”: Liberian Independence and the Contested Meaning of a Black Republic

Historians have primarily examined the African colonization movement within the context of domestic anti-slavery politics; however, because colonizationists often promoted Liberia as a nascent “United States of Africa,” it can also be understood as one of the United States’ first attempts to engineer republicanism abroad. This article examines the symbolic realization of this republican ideal by investigating the often-overlooked moment in 1847 when Liberia declared itself the world’s second black republic. Some white colonization supporters in the United States viewed Liberia’s realization of independence as validation of the idea that a black colony, through U.S. tutelage, could be elevated to become a sovereign, self-governing nation. At the same time, several African American critics argued in pamphlets, abolitionist newspapers, and black political conventions that Liberia’s independence would do little to earn international respect for African Americans and that the event was primarily aimed at garnering support for a colonization movement which had, in fact, contributed to the erosion of black rights in the United States. This article argues that U.S. observers both championed and dismissed Liberian independence as an expression of the United States’ ability to shape the world in its own image at a moment when many Americans were preoccupied with expanding onto new territory as well as policing the boundaries of racialized citizenship within the nation.

Short‐term upwelling events at the western African coast related to synoptic atmospheric structures as derived from satellite observations

Satellite scatterometers provide continuously valuable surface wind speed and direction estimates over the global ocean on a regular grid both in space and time. The Level 3 data derived from the Advanced Scatterometer (ASCAT), available at 1/4° spatial resolution (hereafter AS25), and Quick Scatterometer (QuikSCAT), available on 1/2° and 1/4° horizontal grids (QS50 and QS25, respectively), are studied at regional scales in both the Benguela and Canary upwelling systems. They are compared to the European Center for Medium‐Range Weather Forecast surface wind analysis, with insight into their intrinsic and actual spatial resolutions. In the coastal band, the finest spatial patterns are found in the QS25 winds and are O(75 km). This demonstrates the sensitivity of the high‐resolution satellite‐derived winds to coastal processes related to sea surface temperature (SST) perturbations and land‐sea transition. Next, short‐lived upwelling episodes (SUEs) calculated from SST anomalies are defined consistently with the QS25 actual resolution. These cold events refer to local, short‐lived perturbations that add to seasonal upwelling variability. We characterize concomitant atmospheric synoptic conditions for SUEs identified at chosen latitudes and highlight two subregions in both upwelling systems, with contrasted patterns for the alongshore wind stress component and curl. The complexity of the latter patterns is closely linked to local, short‐term SST variability. Closer to the shore, numerical sensitivity experiments show that the imbalance between Ekman transport and Ekman pumping has an impact on ocean dynamics: wind reduction in the coastal QS25 forcing, partially induced by orography, tends to reduce coastal SST cooling.

Decadal changes in the structure of Cymodocea nodosa seagrass meadows: Natural vs. human influences

Seagrass meadows are deteriorating worldwide. However, numerous declines are still unreported, which avoid accurate evaluations of seagrass global trends. This is particularly relevant for the western African coast and nearby oceanic archipelagos in the eastern Atlantic. The seagrass Cymodocea nodosa is an ‘ecological engineer’ on shallow soft bottoms of the Canary Islands. A comparative decadal study was conducted in 21 C. nodosa seagrass meadows at Gran Canaria Island to compare the structure (shoot density, leaf length and cover) between 2003 and 2012. Overall, 11 meadows exhibited a severe regression, while 10 remained relatively stable. During this period, natural influences (sea surface temperature, Chlorophyll-a concentration and PAR light, as well as the number of storm episodes detaching seagrasses) had a low predictive power on temporal patterns in seagrass structure. In contrast, proximity from a range of human-mediated influences (e.g. the number of outfalls and ports) seem to be related to the loss of seagrass; the rate of seagrass erosion between 2003 and 2012 was significantly predicted by the number of human-mediated impacts around each meadow. This result highlights promoting management actions to conserve meadows of C. nodosa at the study region through efficient management of local impacts.

The House on Bayou Road: Atlantic Creole Networks in the Eighteenth and Nineteenth Centuries

In 1813 a free man of color named Charles Decoudreau living in New Orleans went to court to repossess a house on the edge of town he had sold two years before to Charles Lamerenx, a white man from Saint Domingue. Despite being on opposite sides of a racial divide, the men and their families had much in common as “Atlantic creoles.” In this study, I test the meaning and explanatory power of Ira Berlin's concept of “Atlantic creole” by telling the story of two families, one “black” and one “white,” whose paths briefly crossed in New Orleans in 1811. Berlin's work on “Atlantic creoles” is a powerful intervention in this field because it begins by telling a familiar story and proceeds with a much less familiar one. The familiar story is that of Africans being forcibly taken to America and stripped of their African identities, and developing a new creole or African American culture that was the product of their experience as slaves working in the plantations. Important as this story is, it captures “only a portion of the history of black life in colonial North America, and that imperfectly.” The story as usually told begins with an unadulterated “African” identity that was somehow erased or transformed by the experience of slavery and gave way to a creole identity that was a mix of various African, European, and Native American components. Inverting this story of origins, Berlin shows that the Africans of the charter generations were always already creole: their experiences and attitudes “were more akin to that of confident, sophisticated natives than of vulnerable newcomers.” Atlantic creoles originated in the encounters between Europeans and Africans on the western coast of Africa, starting in the fifteenth century, well before Christopher Columbus sailed to America. In a few coastal enclaves, groups of multilingual Eurafricans acted as intermediaries between Europeans, North African Muslims, and inland Africans. The first generations of slaves brought to America came from these enclaves. Atlantic societies predating the plantation system were societies with slaves rather than slave societies, and there were important social and cultural similarities between the European enclaves on the western coast of Africa (Elmina and Saint-Louis, for example) and the European enclaves in North America and the Caribbean (New Orleans, Charleston, Cartagena, and Cap-Français, for example). Those who circulated among these enclaves, whether slave or free, were likely to be multilingual and highly skilled. Manumissions were frequent, and, no matter how brutal master-slave relations may have been, the distance between master and slave was not incommensurable. Berlin explains his choice of the term creole by referring to the etymology of the Portuguese term crioulo meaning, according to him, “a person of African descent born in the New World.” Among the competing and mutually exclusive definitions of the term, he uses creole to mean “black people of native American birth,” while Atlantic creole includes “those who by experience or chance, as well as by birth, became part of a new culture that emerged along the Atlantic littoral—in Africa, Europe, or the Americas—beginning in the 16th century.”1

Estimating the hydrogen isotopic composition of past precipitation using leaf-waxes from western Africa

The hydrogen isotopic composition of plant leaf-wax n-alkanes (δDwax) is a novel proxy for estimating δD of past precipitation (δDp). However, vegetation life-form and relative humidity exert secondary effects on δDwax, preventing quantitative estimates of past δDp. Here, we present an approach for removing the effect of vegetation-type and relative humidity from δDwax and thus for directly estimating past δDp. We test this approach on modern day (late Holocene; 0–3 ka) sediments from a transect of 9 marine cores spanning 21°N–23°S off the western coast of Africa. We estimate vegetation type (C3 tree versus C4 grass) using δ13C of leaf-wax n-alkanes and correct δDwax for vegetation-type with previously-derived apparent fractionation factors for each vegetation type. Late Holocene vegetation-corrected δDwax (δDvc) displays a good fit with modern-day δDp, suggesting that the effects of vegetation type and relative humidity have both been removed and thus that δDvc is a good estimate of δDp. We find that the magnitude of the effect of C3 tree – C4 grass changes on δDwax is small compared to δDp changes. We go on to estimate δDvc for the mid-Holocene (6–8 ka), the Last Glacial Maximum (LGM; 19–23 ka) and Heinrich Stadial 1 (HS1; 16–18.5 ka). In terms of past hydrological changes, our leaf-wax based estimates of δDp mostly reflect changes in wet season intensity, which is complementary to estimates of wet season length based on leaf-wax δ13C.

Dispatches

Dispatches

First record of a gravid female and neonate of the Lusitanian cownose ray, Rhinoptera marginata, from the eastern Mediterranean Sea

Elasmobranch populations within the eastern Mediterranean Sea are in decline because of both direct and indirect fishing pressure from bottom trawl fisheries. Unfortunately biological information pertaining to these cartilagenous fish within this region is extremely limited and the harvest of these species is unregulated (Basusta et al., 2008; Cek et al., 2009; TFS, 2009; Ceyhan et al., 2010). This combination of factors has led to the depletion of many elasmobranchii throughout the worlds oceans (e.g. Dulvy and Reynolds, 2002; Sulikowski et al., 2007) and continues to limit the development of management plans (e.g. Hoff and Musick, 1990; Leaman, 1991; Munk, 2001). The Lusitanian cownose ray (Rhinoptera marginata) is a large epibenthic ray that inhabits sandy and muddy substrate at depths between 20 and 100 m along the western coasts of Africa and the Mediterranean Sea (Whitehead et al., 1984; Golani et al., 2006). R. marginata is the only Rhinopterid species in the Mediterranean Sea where this batiod is considered rare (Basusta and Erdem, 2000). Information pertaining to this species has thus been limited to systematic and distribution studies (Basusta and Erdem, 2000; Quignard and Tomasini, 2000; Bilecenoglu et al., 2002). The rarity of R. marginata coupled with the lack of biological data has led to its designation by the IUCN as Near Threatened (Abdul Malak et al., 2011). Owing to the recent commercial interest in this elasmobranch species and a potentially small population size, information on the life history of R. Marginata is both timely and imperative. Information herein provides the first account of the reproductive biology of this species in the Mediterranean Sea, a fundamental aspect essential for the proper management of this species (Walker, 2005).