RÉSUMÉObjectif : L'objectif de cette étude est d'évaluer la qualité de l'eau des puits à partir de ses caractéristiques physico-chimiques dans la commune de Pobè. Méthodologie et résultats : L'étude entreprise entre juin 2012 et mars 2013 a permis de mesurer au niveau de quinze puits les paramètres physiques tels que le pH, la conductivité électrique (CE) et la température (T) de l'eau ainsi que les paramètres chimiques suivants : bicarbonates (HCO3 -), chlorures (Cl -), calcium (Ca 2+ ), magnésium (Mg 2+ ), titre hydrotimétrique ou dureté totale (TH), ammonium (NH4 + ), nitrates (NO3 -), nitrites (NO2 -), sulfates (SO4 2-), phosphates (PO4 3-) et fluorures (F -). Les valeurs moyennes annuelles sont comparées aux normes relatives à la qualité de l'eau de boisson. L'analyse statistique multivariée dont l'Analyse en Composantes Principales (ACP) et la Classification Hiérarchique Ascendante (CHA) a été également appliquée à l'ensemble des paramètres mesurés. L'eau des puits est légèrement acide avec un pH moyen de 5,83 ± 0,6. Elle est faiblement minéralisée et légèrement dure avec une conductivité moyenne de 236,62 ± 135,54 µS/cm et une dureté totale moyenne de 107,8 ± 40,63 mg/L. La pollution azotée est un indicateur majeur de la qualité de l'eau des puits étudiés. Cette pollution se traduit par des taux élevés en nitrates et en ammonium dans plus de 50 % des puits. Une forte corrélation est signalée entre la conductivité électrique et les paramètres suivants : pH, NO3 -, NO2 -, SO4 2-, TH, Cl -, HCO3 -et Ca 2+ . La typologie est principalement gouvernée par cette conductivité qui permet de classifier les puits selon leur qualité physico-chimique. Conclusion et applications : L'eau des puits est soumise à une pollution organique dans la commune de Pobè. Cette pollution d'origine anthropique serait liée à l'infiltration des eaux usées et des engrais chimiques. Les fortes teneurs en nitrates et en ammonium montrent que cette eau est chimiquement non appropriée à la consommation humaine et nécessite dans la majorité des puits un traitement préalable. Mots clés : Physico-chimie, eau de puits, pollution, analyses multivariées, Pobè. Physicochemical characteristics of well water in Pobè municipality, Benin, West Africa ABSTRACT Objective : The aim of this study is to evaluate the quality of well water for its physical and chemical characteristics in the municipality of Pobè. Methodology and Results: The study conducted from June 2012 to March 2013 measured in fifteen wells the level of physical parameters such as pH, electrical conductivity and water temperature as well as the following chemical parameters: bicarbonate (HCO3 -), chloride (Cl -), calcium (Ca 2+ ), magnesium (Mg 2+ ), total hardness (TH), ammonium (NH4 + ), nitrate (NO3 -), nitrite (NO2 -), sulphate (SO4 2-), phosphate (PO4 3-) and fluoride (F -). The annual mean values are compared to standards for drinking water quality. Statistical multivariate analysis including Principal Component Analysis and hierarchical clustering was also applied to all measured ...
This paper presents a new species of cavernicolan planarian from the African continent, which enabled us to determine the position of the suborder Cavernicola within the order Tricladida on a molecular basis. A recent paper suggested a sister-group relationship between Cavernicola and marine triclads. However, our work is the first molecular study to demonstrate unequivocally that the Cavernicola does not group with either the freshwater planarians or the land planarians, i.e. is not closely related to the suborder Continenticola, and corroborates the suggested sister-group relationship with the marine triclads or Maricola. Two possible scenarios are proposed for the evolution of the Cavernicola from marine ancestors. The new species is assigned to the genus Novomitchellia and is characterized by the absence of eyes. Testicular follicles are numerous and only dorsal, extending from behind the ovaries to the posterior end of the body. The vasa deferentia separately penetrate the penis bulb and the seminal vesicle. The penis papilla is very short and blunt, and the penis bulb musculature is weak. A long and narrow copulatory bursa is situated behind the gonopore. The common oviduct is orientated perpendicularly to the short bursal canal.
Ovaries of Haplotaxis sp. were studied in active and nonactive states, that is, in a sexually mature specimen and in specimens outside of the reproductive period. Two pairs of ovaries were found in segments XI and XII. Especially in the nonactive state, they were in close contact with copulatory glands. Each ovary was composed of germ cells interconnected with syncytial cysts, which were enveloped by a layer of somatic cells. Within cysts each germ cell had one ring canal connecting it to the common anuclear cytoplasmic mass called a cytophore. During oogenesis clustering germ cells differentiated into nurse cells and oocytes; thus, the oogenesis was recognized as meroistic. Vitellogenic oocytes were detached from the ovaries and continued yolk absorption within the body cavity. Because recent studies have shown the variety of ovaries and germ line cyst organization in clitellates and suggest their evolutionary conservatism at the family or subfamily level, the data presented here can be valid in understanding the phylogenetic relationships among Clitellata. In this context, ovaries found in Haplotaxis sp. resembled those of the "Tubifex" type. "Tubifex" ovaries are characteristic for numerous microdrile taxa (tubificines, limnodriloidines, propappids, lumbriculids, and leech-like branchiobdellids) and can be regarded as the primary character for these Clitellata in which germ-line cysts are formed during early oogenesis. As the family Haplotaxidae is currently considered to be paraphyletic and the species studied here belongs to Haplotaxidae sensu stricto, our results support the close relationship of Haplotaxidae sensu stricto to the clade consisting of Lumbriculidae, Branchiobdellida, and Hirudinida, in which lumbriculids are sister to the latter two.
This study performed in South-Eastern Benin aims to correlate the regional subterranean aquatic fauna, still poorly unknown, with the main physico-chemical characteristics of well-water used by human populations. Two kinds of descriptors are used. Physicochemical analyses of water and faunistic sampling were consequently performed for one year at 15 stations. Multivariate analyses show different groups of stations depending on the kind of descriptor. Thus it appears that, in the Pob e region, the water quality, very variable from one station to another, is certainly not the main determinant of the wellwater fauna distribution. Among the subterranean crustaceans, species belonging to genera Allocyclops and Metastenasellus have never been described before. These results are a contribution to the knowledge of the regional biodiversity and suggest that this biodiversity can be used as an indicator for better protection of regional groundwater.
Citation: Fiers F, Lagnika M (2015) Four new representatives of the genus Allocyclops Kiefer, 1932 from semi-consolidated subsoil aquifers in Benin (Copepoda, Cyclopoida, Cyclopidae). Subterranean Biology 16: 1-36. Abstract Several species of cyclopoid copepods were collected from improved and unimproved hang-dug-wells in the Republic of Bénin over the years 2009-2014. Fifty five wells located in seven different districts were sampled: 15 wells in the district of Pobè (Department Plateau) and 1 well in Kétou (Department Plateau), 4 wells in Porto-Novo District (Department Ouémé) and, 15 wells in Lokossa District (Department Mono),18 wells in Parakou District (Department Borgou), 1 well in Abomey-Calavi District (Depart-ment Atlantique) and 1 in Zogbodomè District (Department Zou). Among them, 4 new species of the genus Allocyclops Kiefer, 1932 were found and are described herein: Allocyclops spinifer sp. n., A. nudus sp. n., A. pilosus sp. n. and A. sakitii sp. n. They are compared with the three African species previously described. Allocyclops appears to be a sub-Saharan taxon specialized to thrive in the variable environment of subsoil aquifers in laterite deck beds. An identification key to the 7 different African Allocyclops species is provided.
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