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[Display omitted] • We studied the diversification of monogenean gill parasite Dolicirroplectanum lacustre infecting introduced Nile perch. • Parasite co-introduction led to reduced morphological and genetic diversity in Lake Victoria. • High morphological diversity in Lake Albert indicates a phenotypic plasticity of D. lacustre. • Intraspecific diversification in D. lacustre was demonstrated by the presence of two morphotypes. • Mitonuclear discordance indicates an incomplete reproductive barrier between the morphotypes. The Nile perch (Lates niloticus) is a notorious invasive species. The introductions of Nile perch into several lakes and rivers in the Lake Victoria region led to the impoverishment of trophic food webs, particularly well documented in Lake Victoria. Additionally, its parasites were co-introduced, including Dolicirroplectanum lacustre (Monogenea, Diplectanidae). Dolicirroplectanum lacustre is the single monogenean gill parasite of latid fishes (Lates spp.) inhabiting several major African freshwater systems. We examined the intra-specific diversification of D. lacustre from Lates niloticus in Lake Albert, Uganda (native range) and Lake Victoria (introduced range) by assessing morphological and genetic differentiation, and microhabitat preference. We expected reduced morphological and genetic diversity for D. lacustre in Lake Victoria compared with Lake Albert, as a result of the historical introductions. We found that D. lacustre displayed high morphological variability within and between African freshwaters, with two morphotypes identified, as in former studies. The single shared morphotype between Lake Albert and Lake Victoria displayed similar levels of haplotype and nucleotide diversity between the lakes. Mitonuclear discordance within the morphotypes of D. lacustre indicates an incomplete reproductive barrier between the morphotypes. The diversification in the mitochondrial gene portion is directly linked with the morphotypes, while the nuclear gene portions indicate conspecificity. Based on our results, we reported reduced genetic and morphological diversity, potentially being a result of a founder effect in Lake Victoria. [ABSTRACT FROM AUTHOR]

The early Pliocene fan delta complex developed in the south of Lake Albert Basin which is located at the northern end of the western branch in the East African Rift System. The stratigraphy of this succession is composed of distributary channels, overbank, mouthbar and lacustrine shales. Limited by the poor seismic quality and few wells, it is full of challenge to delineate the distribution area and patterns of reservoir sands. Sedimentary forward simulation and basin analogue were applied to analyze the spatial distribution of facies configuration and then a conceptual sedimentary model was constructed by combining with core, heavy mineral and palynology evidences. A 3D geological model of a 120 m thick stratigraphic succession was built using well logs and seismic surfaces based on the established sedimentary model. The facies modeling followed a hierarchical object-based approach conditioned to multiple trend constraints like channel intensity, channel azimuth and channel width. Lacustrine shales were modeled as background facies and then in turn eroded by distribute channels, overbank and mouthbar respectively. At the same time a body facies parameter was created to indicate the connectivity of the reservoir sands. The resultant 3D facies distributions showed that the distributary channels flowed from east bounding fault to west flank and overbank was adhered to the fringe of channels while mouthbar located at the end of channels. Furthermore, porosity and permeability were modeled using sequential Gaussian simulation (SGS) honoring core observations and petrophysical interpretation results. Despite the poor seismic is not supported to give enough information for fan delta sand distribution, creating a truly representative 3D geomodel is still able to be achieved. This paper highlights the integration of various data and comprehensive steps of building a consistent representative 3D geocellular fan delta model used for numeral simulation studies and field development plan. [ABSTRACT FROM AUTHOR]

The Holocene turbidite systems of Lake Kivu and the Pliocene turbidite systems of Lake Albert in the East African Rift were examined using high-resolution 2-D and 3-D seismic reflection data and sediment core information. Based on investigations of seismic facies and lithofacies, several key turbidity-flow depositional elements were observed, including channels, overbank levees with sediment waves, and depositional lobes. Analyses of the sources of the recent and ancient turbidite systems in these two extensional basins suggest that flood-induced hyperpycnal flows are important triggers of turbidity currents in lacustrine rift basins. From source to sink, sediment dispersal, facies distribution, and depositional thickness of the turbidite systems are strongly influenced by rift topography. The Lake Kivu and Lake Albert rifts serve as excellent analogues for understanding the sedimentary patterns of lacustrine turbidites in extensional basins. [ABSTRACT FROM AUTHOR]

Micronutrient deficiencies and food insecurity constitute major threats to human health across Africa. With decreasing availability of large-bodied fishes (>20 cm), strategies have developed to target small pelagic fish (SPF) species (<20 cm total length) to improve the food availability; yet little is known regarding their nutritional content. Three species of SPFs - Engraulicypris bredoi (muziri), Brycinus nurse (ragoogi) and Rastrineobola argentea (mukene) - were collected from lakes Albert, Victoria, and Nabugabo in Uganda, East Africa. The content of essential elements (Ca, Fe, K, Mg, Na, P, Se, and Zn) and non-essential, potentially toxic elements (Cd and Pb) were measured and compared in fishes across landing sites within lakes Victoria (R. argentea) and Albert (B. nurse, E. bredoi) and between lakes (R. argentea). Rastrineobola argentea was the most nutritious of the fishes examined, although some variation was present in their elemental concentration among landing sites. Overall, all three species contain high levels of essential nutrients and fall within a safe range for non-essential, toxic elements based on current consumption habits. These SPFs can play an important role in addressing nutritional deficiencies in Uganda, and effort should be made to increase the availability, accessibility, and consumption of these under-utilized small fishes. • Quantification of the content of elements in small fishes in Uganda. • Species analyzed provide high levels of vital elements (Ca, Fe, Zn). • Some differences are apparent in elemental concentrations within and between lakes. • Species analyzed are low in non-essential elements (Cd, Pb). • Nutritional value of species is highly relevant for human health and food security in East Africa. [ABSTRACT FROM AUTHOR]

Abstract: New biomarker analyses from Lake Albert, East Africa spanning ~15–9ka show the most extreme, abrupt, multi-stage climate and environmental shifts during the last deglacial transition of anywhere in Africa. Records of hydroclimate expressed in compound specific δD values from terrestrial leaf waxes and a TEX86 paleotemperature record support multiple stages of pronounced drying and cooling from 13.8 to 11.5ka and demonstrate the dynamic behavior of the low latitude tropics during the deglaciation. The vegetation response, illustrated by compound specific δ13C values and fossil pollen records, was an expansion of C4 grassland when the region was cool and arid. These results advance our understanding of a spatially and temporally complex regional response to global climate forcing, suggesting weakening of the Indian Ocean monsoon at the end of the Pleistocene that coincides with a minor decrease in the rate of the Atlantic Meridional Overturning Circulation (AMOC) and during a time of stepwise cooling in the northern high latitudes. [Copyright &y& Elsevier]

Abstract: In order to investigate the capacity of being intermediate host for Schistosoma mansoni, the Ugandan F1 generation of Biomphalaria snail species that were laboratory-bred from parent populations originally collected from either Lake Victoria or Lake Albert was challenged with sympatric and non-sympatric S. mansoni isolates. After a prepatent period of 20 days, a daily 10-hourly snail shedding for cercariae was done to determine the infection rate, cercarial production per hour and survival period of infected snails. The study suggests that when parasite strains from a different geographical origin is used for infection, survival of infected snails increase, leading to an increased transmission potential. Although earlier literature had indicated that the Lake Victoria Biomphalaria sudanica is refractory to S. mansoni, we showed that all Ugandan Biomphalaria spp., including B. sudanica from all locations, were highly susceptible to the S. mansoni isolates. Thus if B. choanomphala, which is an efficient intermediate host in Lake Victoria, is given an opportunity to occupy Lake Albert, it will most likely be compatible with the Albertine S. mansoni parasites. Equally, if B. stanleyi, currently restricted to Lake Albert invades Lake Victoria, it is likely to act as an efficient intermediate host. Future work should concentrate on intraspecific population-level differences in compatibility. [Copyright &y& Elsevier]