Benthic foraminifera off West Africa (1°N to 32°S)

Recent benthic foraminifera (> 125 µm) were investigated from multicorer samples on a latitudinal transect of 20 stations between 1°N and 32°S along the upper slope off West Africa. Samples were selected from a narrow water depth interval, between 1200 and 1500 m, so that changes in water masses are minimized, but changes in surface productivity are important and the only significant environmental variable. Live (Rose Bengal stained) benthic foraminifera were counted from the surface sediment down to a maximum of 12 cm. Dead foraminifera were investigated in the top 5 cm of the sediment only. Five live and five dead benthic foraminiferal assemblages were identified using Q-mode principal component analysis, matching distinct primary productivity provinces, characterized by different systems of seasonal and permanent upwelling. Differences in seasonality, quantity, and quality of food supply are the main controlling parameters on species composition and distribution of the benthic foraminiferal faunas. To test the sensitivity of foraminiferal studies based on the uppermost centimeter of sediment only, a comparative Q-mode principal component analysis was conducted on live and dead foraminiferal data from the top 1 cm of sediment. It has been demonstrated that, on the upper slope off West Africa, most of the environmental signals as recorded by species composition and distribution of the 'total' live and dead assemblages, i.e., including live and dead foraminifera from the surface sediment down to 12 cm and 5 cm, respectively, can be extracted from the assemblages in the top centimeter of sediment only. On the contrary, subsurface abundance maxima of live foraminifera and dissolution of empty tests strongly bias quantitative approaches based on the calculation of standing stocks and foraminiferal numbers in the topmost centimeter.

Organic and inorganic geochemical measurements of sediment core GeoB7702-3

It has long been known that extreme changes in North African hydroclimate occurred during the late Pleistocene yet many discrepancies exist between sites regarding the timing, duration and abruptness of events such as Heinrich Stadial (HS) 1 and the African Humid Period (AHP). The hydroclimate history of the Nile River is of particular interest due to its lengthy human occupation history yet there are presently few continuous archives from the Nile River corridor, and pre-Holocene studies are rare. Here we present new organic and inorganic geochemical records of Nile Basin hydroclimate from an eastern Mediterranean (EM) Sea sediment core spanning the past 28 ka BP. Our multi-proxy records reflect the fluctuating inputs of Blue Nile versus White Nile material to the EM Sea in response to gradual changes in local insolation and also capture abrupt hydroclimate events driven by remote climate forcings, such as HS1. We find strong evidence for extreme aridity within the Nile Basin evolving in two distinct phases during HS1, from 17.5 to 16 ka BP and from 16 to 14.5 ka BP, whereas peak wet conditions during the AHP are observed from 9 to 7 ka BP. We find that zonal movements of the Congo Air Boundary (CAB), and associated shifts in the dominant moisture source (Atlantic versus Indian Ocean moisture) to the Nile Basin, likely contributed to abrupt hydroclimate variability in northern East Africa during HS1 and the AHP as well as to non-linear behavior of hydroclimate proxies. We note that different proxies show variable gradual and abrupt responses to individual hydroclimate events, and thus might have different inherent sensitivities, which may be a factor contributing to the controversy surrounding the abruptness of past events such as the AHP. During the Late Pleistocene the Nile Basin experienced extreme hydroclimate fluctuations, which presumably impacted Paleolithic cultures residing along the Nile corridor.

Communities and microhabitats of living benthic foraminifera from the tropical East Atlantic

Living (Rose Bengal stained) benthic foraminifera were collected with a multicorer from six stations between 2°N and 12°S off West Africa. The foraminiferal communities in the investigated area reflect the direct influence of different productivity regimes, and are characterized by spatially and seasonally varying upwelling activity. At five stations, foraminiferal abundance coincides well with the gradient of surface productivity. However, at one station off the Congo River, the influence of strong fresh water discharge is documented. Although this station lies directly in the center of an upwelling area, foraminiferal standing stocks are surprisingly low. It is suggested that the Congo discharge may induce a fractionation of the organic matter into small and light particles of low nutritional content, by contrast to the relatively fast-sinking aggregates found in the centers of high productivity areas. Quality and quantity of the organic matter seem to influence the distribution of microhabitats as well. The flux of organic carbon to the sea-floor controls the sequence of degradation of organic matter in sediment and the position of different redox fronts. The vertical foraminiferal stratification within sediment closely parallels the distribution of oxygen and nitrate in porewater, and reflects different nutritive strategies and adaptation to different types of organic matter. The epifauna and shallow infauna colonize oxygenated sediments where labile organic matter is available. The intermediate infauna (M. barleeanum) is linked to the zone of nitrate reduction in sediments where epifaunal and shallow infaunal species are not competitive anymore, and must feed on bacterial biomass or on metabolizable nutritious particles produced by bacterial degradation of more refractory organic matter. The deep infauna shows its maximum distribution in anoxic sediments, where no easily metabolizable organic matter is available.

Les lois organiques des colonies; documents officiels précédés de notices historiques.

t.1. Colonies britanniques.--t.2. Colonies françaises.--t.3. Colonies françaises (suite) Colonies néerlandaises: Indes orientales néerlandaises; Surinam. Colonies allemandes. Colonie italienne de l'Érythrée. État indépendant du Congo.

Peace handbooks /

Contents cont'd.--v. 18. German African possessions (late), no. 110-114.--v. 19. Portuguese possessions, no. 115-121.--v. 20. Spanish and Italian possessions : Independent states, no. 122-130.--v. 21. North, Central and South America : Atlantic Islands, no. 131-138.--v. 22. Pacific Islands, no. 139-147.--v. 23. International affairs, no. 148--152.--v. 24. Congresses : German Opinion, no. 153-157.--v. 25. Indemnities, Plebiscites, etc., no. 158-161.

Annuaire statistique de la Belgique.

Mode of access: Internet.

Annales.

Series 1: Iconographies; series 2: Varia; series 3: Missions; series 4: Katanga; series 5: Congo-Kasai (v.3, no. 1, 3 called "Flore du Bas-et du Moyen-Congo," v. 3, no. 2 called "Baset Moyen-Congo. Flore du Bas-et du Moyen-Congo"; v.4, no. 1 called "Bas-et Moyen-Congo. Notes botaniques sur la région du Bas-et Moyen-Congo"); series 6: Monographies.

La question africaine,

Le Portugal.--L'État indépendent du Congo.--Le Congo belge.--L'avenir de l'Afrique.

Histoire générale des voyages, ou, Nouvelle collection de toutes les relations de voyages par mer et par terre, qui ont été publiées jusqu'à présent dans les différentes langues de toutes les nations connues : ce qui'il y a de plus remarquable, de plus utile et de mieux averé dans les pays ou les voyageurs ont penetré, avec les moeurs des habitans, la religion, les usages, arts, sciences, commerce, manufactures, &c, pour former un systême complet d'histoire & de géographie moderne, qui représente l'état actuel de toutes les nations : enrichi de cartes géographiques et de figures; Tome quinziéme.

Contiene: Premiere partie, Suite du Livre Xe. contenant la description des costes depuis rio da Volta jusqu'au cap Lope Consalvo. - Premiere partie, Livre onziéme, Voyages dans la Guinée et au Royaume de Benin, contenant la description du Royaume de Benin & de toute la cote, jusqu'a Royaume de Congo. - [Se incluye el relato de D'Elbée en 1669-70].

Histoire générale des voyages, ou, Nouvelle collection de toutes les relations de voyages par mer et par terre, qui ont été publiées jusqu'à présent dans les différentes langues de toutes les nations connues : ce qui'il y a de plus remarquable, de plus utile et de mieux averé dans les pays ou les voyageurs ont penetré, avec les moeurs des habitans, la religion, les usages, arts, sciences, commerce, manufactures, &c, pour former un systême complet d'histoire & de géographie moderne, qui représente l'état actuel de toutes les nations : enrichi de cartes géographiques et de figures; Tome seiziéme.

Premiere partie, Livre douziéme, Voyages dans les Royaumes de Congo et d'Angola. - Premiere partie, Livre treiziéme, Description des Royaumes de Loango, de Congo, d'Angola, de Benguela & des pays voisins. - Table des chapitres et paragraphes contenus dans [volumes XIII, XIV, XV, XVI]. - Avis aux relieurs pour placer les cartes. - [Se incluyen los viajes de Lopez en 1578, Battel en 1589, Angelo en 1666, Carli en 1667, Merolla en 1682-88, Barbot le Jeune en 1700].

Histoire générale des voyages, ou, Nouvelle collection de toutes les relations de voyages par mer et par terre, qui ont été publiées jusqu'à présent dans les différentes langues de toutes les nations connues : ce qui'il y a de plus remarquable, de plus utile et de mieux averé dans les pays ou les voyageurs ont penetré, avec les moeurs des habitans, la religion, les usages, arts, sciences, commerce, manufactures, &c, pour former un systême complet d'histoire & de géographie moderne, qui représente l'état actuel de toutes les nations : enrichi de cartes géographiques et de figures; Tome dix-septiéme.

Contiene: Premiere partie, Suite du Livre XIIIe et de la description des Royaumes de Congo, d'Angola, de Benguela, et des pays voisins. - Premiere partie, Livre quatorziéme, Description des pays qui bordent la cote orientale d'Afrique, depuis le cap de Bonne-Esperance jusqu'au cap de Guardasu. - [Se incluye el relato de Kolben de 1713].