International Letters of Natural Sciences Vol. 78

Abstract: The study aimed at identifying and mapping groundwater potential zones in agricultural intensive Sarada river basin using Remote sensing and GIS technology. Zones of water potentiality were mapped integrating various information layers in GIS environment which eventually helped weighted modeling to arrive at the final outcome. Hydrogeomorphic units such as alluvial plains, valley fills, shallow weathered pediplains and deeply weathered pediplainswere mapped. Eventually water potential zones in the basin were mapped and categorised them in to ‘excellent’, ‘good’, ‘moderate’ and ‘poor’. The study highlighted the effective use of Remote sensing and GIS technology for integrated analysis, identification and mapping of the groundwater potential zones in the Sarada river basin.

Abstract: The atricle is devoted to the study of the cultivation of cyanobacteria Microcystis aeruginosa (Kützing) Kützing, Microcystis pulverea (H.C.Wood) Forti. in the presence of basalt tuff. The possibility of using basalt tuff as an adsorbing material for regulating the number of cyanobacteria and preventing toxic “water bloom” in fluid circuits. The study analyzes the change in the biomass amount and the dynamics of the proportion of dead cyanobacteria in response to the presence of basalt tuff in the culture medium. It is noted that the use of basalt tuff leads to a decrease in the growth activity of cultures of Microcystis aeruginosa, Microcystis pulverea, manifested in an increase in the number of dead cells and slowdown the accumulation of cyanobacterial biomass. These effects are the result of a decrease in the amount of available nitrogen in the nutrient medium.

Abstract: The study of feeding ecology and reproductive biology ensures that the right management measures are applied for best output of fish stocks. Selection of good fish species for culture is also made possible through feeding and reproductive studies. Ghana over-relies on the culture of Nile tilapia and African catfish because there is no reliable scientific information on potential fish species that can be included for fish farming. The current study sought to investigate food habits and reproductive characteristics of economically important fish species in the Tono Reservoir of Northern Ghana. Monthly sampling was carried out from January, 2015 to December, 2016 (24 months). Specimens were obtained using cast net and gillnets of varying mesh sizes. Specimens were immediately transported to the laboratory in a chilled iced chest of temperature 4 for morphometric measurements and microscopic analysis of gut content and gonads. Thirty-three (33) individual food items were identified from all the fish species. Phytoplankton was the most important diet (Index of Relative Importance, IRI = 1923) whereas zooplankton was the least important diet (IRI = 35) out of the five major categories of food items identified from all the fish species. The major peaks of gonadosomatic index (GSI) of females were noted in February – March and June – July. Over 80 % variation of fecundity was explained by the predictors (standard length, fish weight and gonad weight) for Clarias gariepinus and Auchenoglanis occidentalis. All the fish species were classified as omnivores and they spawned more than once in a year making all of them good candidates for aquaculture. Management measures should focus on regulating agricultural activities close to the reservoir and fishing activities in the reservoir for sustainable fish production and exploitation.

Abstract: Tree species differ in litter quality and belowground biomass, thereby exerting species-specific impact on soil properties and microbial biomass. A study was conducted to find out the comparative effects of Podocarpus falcatus and Croton macrostachys on basic soil characteristics and microbial biomass, in the Munessa forest, Ethiopia. Four experimental plots under the canopies the respected tree species (two from each) were established for sample collection. From these plots, soil samples were collected from a depth 0-10 cm and 10-25 cm. The results showed that, from the depth 0-10 cm, concentration of organic carbon (C) and nitrogen (N) was larger under C. macrostachys and from the depth 10-25 cm these values were greater under P. falcatus. There was significant difference (p < 0.05) in cation exchange capacity being larger under C. macrostachys. There were no differences in microbial composition between the plots. However, the total phospholipid fatty acids (PLFA) concentration as an entry for microbial biomass determination tended to be significantly larger in soil under Podocarpus plots (382.7 ± 60.9 nmol PLFA g^-1 dry soil) vs. 262.2 ± 32.8 nmol PLFA g^-1 dry soil (Croton plots). The varying impacts of tree species on soil characteristics and microbial biomass may be partly explained by differences in functional traits related to life-history strategy of the respected species.