The Lake CHAd Deep DRILLing project (CHADRILL) - targeting ~ 10 million years of environmental and climate change in Africa

At present, Lake Chad ( ~13°0 N, ~14° E) is a shallow freshwater lake located in the Sahel/Sahara region of central northern Africa. The lake is primarily fed by the Chari-Logone river system draining a ~600 000 km2 watershed in tropical Africa. Discharge is strongly controlled by the annual passage of the intertropical convergence zone (ITCZ) and monsoon circulation leading to a peak in rainfall during boreal summer. During recent decades, a large number of studies have been carried out in the Lake Chad Basin (LCB). They have mostly focused on a patchwork of exposed lake sediments and outcrops once inhabited by early hominids. A dataset generated from a 673m long geotechnical borehole drilled in 1973, along with outcrop and seismic reflection studies, reveal several hundred metres of Miocene-Pleistocene lacustrine deposits. CHADRILL aims to recover a sedimentary core spanning the Miocene-Pleistocene sediment succession of Lake Chad through deep drilling. This record will provide significant insights into the modulation of orbitally forced changes in northern African hydroclimate under different climate boundary conditions such as high CO2 and absence of Northern Hemisphere ice sheets. These investigations will also help unravel both the age and the origin of the lake and its current desert surrounding. The LCB is very rich in early hominid fossils (Australopithecus bahrelghazali; Sahelanthropus tchadensis) of Late Miocene age. Thus, retrieving a sediment core from this basin will provide the most continuous climatic and environmental record with which to compare hominid migrations across northern Africa and has major implications for understanding human evolution. Furthermore, due to its dramatic and episodically changing water levels and associated depositional modes, Lake Chad's sediments resemble maybe an analogue for lake systems that were once present on Mars. Consequently, the study of the subsurface biosphere contained in these sediments has the potential to shed light on microbial biodiversity present in this type of depositional environment. We propose to drill a total of ~1800m of poorly to semi-consolidated lacustrine, fluvial, and eolian sediments down to bedrock at a single on-shore site close to the shoreline of present-day Lake Chad. We propose to locate our drilling operations on-shore close to the site where the geotechnical Bol borehole (13°280 N, 14°440 E) was drilled in 1973. This is for two main reasons: (1) nowhere else in the Chad Basin do we have such detailed information about the lithologies to be drilled; and (2) the Bol site is close to the depocentre of the Chad Basin and therefore likely to provide the stratigraphically most continuous sequence

The Study of Airborne Pollen Precipitation in the University of Nigeria (Nsukka) Botanic Garden)

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Pollen Contents Of Commercial Honeys Of Opi, Nsukka, Enugu State, Nigeria

Pollen analyses of seven honey samples from Opi-Nsukka Mini market were evaluated for their pollen composition. The results yielded a total of 77 plants belonging to 40 families of flowering plants. Thirty-three plants were identified to the generic level, while thirty-two plants were identified to the specific levels. The pollen types belonging to members of the plant families of Poaceae, Agavaceae and Combretaceae/ Melastomataceae were classified only to their respective source plant families. The composition of the contributing plant species shows that the honey samples were multifloral honeys derived from a wide range of nectar and pollen sources. Also, pollen types of trees and shrubs of entomophilous plants were predominant in the samples. The qualitative and quantitative composition of pollen grains in the samples were very low in some of the honey samples indicating that some of the honey samples were diluted (adulterated) with non-floral substance (syrup). Some important honey plants identified which are characteristic of Nsukka vegetation and also reflecting common pollen load and nectar sources include Lannea microcarpa, Senna spp, Daniellia oliveri, Parkia biglobosa, Hymenocardia acida, Lophira lanceolata, Syzygium guineense, Parinari spp, Elaeis guineensis, Alchornea cordifolia and members of Combretaceae/Melastomataceae. Keywords: Adulteration, Entomophilous Plants, Multifloral Honey, Pollen. Plant Product Research Journal Vol. 11 2007: pp. 5-1

Airborne pollen and spore survey in relation to allergy and plant pathogens in Nsukka, Nigeria

Airborne bio-particles of allergic significance were recorded at a height of 15m in Nsukka during September 1999 – February 2000. Spores of fungi and pollen grains, which are important part of the exposure that may lead to allergic discomfort and plant diseases, dominated the particles. Other primary sources of the allergic counted included spores of ferns, diatom frustules, algal fragment, insect's parts and charred graminae cuticles. Thirty plant families consisting of 33 pollen types were identified to 10 generic and 23 specific levels. The common pollen grains counted included those of Poaceae, Elaeis guineenis, Casuarina equisetifolia, Asteraceae, Combretaceae/Melastomataceae, Alchornea cordifolia and Amaranthaceae/Chenopodiaceae. The pollen grains of anemophilous plants such as those of Poaceae, Elaeis guineensis, Asteraceae and Casuarina equissetifolia that are regarded among the important causes of allergic rhinitis were commonly counted in the atmosphere. Thirteen spore types of fungi were identified and they belong to three classes: Deuteromycetes, Ascomycetes, and Basidiomycetes. The spores of species of Nigrospora, Ustilago, Cladosporium, Drechelera/Helminthosporium, Fusarium, Alternaria, Puccinia and Curvularia were among the important allergic and pathogenic fungal spore types counted in the study. Bio-Research Vol. 3(1) 2005: 77-8

The Study Of Airborne Pollen And Spores Circulating At “Head Level” In Nsukka Environment

The quantitative air spora investigation at “head” level in the dry season (November-February) revealed a substantial presence of pollen grains, fungal spores and such other component as fern spores, diatom frustules and plant debris. The trapped pollen grains are representative of trees, shrubs, weeds/herbs and grasses of both indigenous and introduced species. Trees and grasses (Poaceae) contributed 49.07% and 30.91% of total pollen, respectively. The qualitative pollen record indicates that more species of entomophilous plants were dominant in the pollen count, whereas pollen grains of anemophilous plants were found to predominate quantitatively. The most frequent and abundant pollen types include those of Poaceae (grasses), Elaeis guineensis, Casuarina equisetifolia, Alchornea cordifolia, Milicia excelsa, and Amaranthaceae / Chenopodiaceae. Fungal spores were found to dominate the entire component of the airborne spora counted. The most common fungal spores encountered include those of Cladosporium, Ustilago, Nigrospora, Drechslera /Helminthosporium and Pithomyces. Bio-Research Vol.2(2) 2004: 7-1