The importance of phytoplankton in fresh water environment cannot be over emphasized. This study was designed to determine the phytoplankton diversity and abundance in water bodies exposed to different anthropogenic pressures. Water samples were collected from 19 water sources in four categories: Car wash, Municipal wastes, Car wash + Municipal wastes and Drinking water. Phytoplankton species were determined following standard procedures. Palmer's pollution index was used to evaluate the status of organic pollution. A total of 66 phytoplankton were identified belonging to 44 genera, 34 families and six phyla. There were 52, 32, 11 and 38 species recorded for Car Wash, Municipal Waste, Car wash + Municipal wastes and Drinking water sources, respectively. Nine species cut across the four categories while 22, three and two species were unique to car wash, municipal wastes and drinking water sources, respectively. Nitzschia and Chlorella were the most abundant genera in the different water sources. While phytoplankton abundance correlated positively with nutrients, diversity correlated negatively. The highest and lowest organic pollution indices (24 and 8 respectively), were recorded in the drinking water category. Car wash activity did not only encourage the growth and diversity of algae but also influenced the establishment of unique species, some which are harmful. Human activities in and around water sources in Buea are thus degrading water quality, putting the population at risk. There is therefore need to protect the water resources of Buea.

Macrophytes can occur as submerged, floating or emergent. They provide not only important structural supports in streams and river habitats, but also absorb and sequester pollutants, provide primary food production, nutrients and habitats to a wide range of macro and micro-organisms living in and around lotic sites. Their existence is however threatened by both anthropogenic and natural stresses. This study aimed to document macrophyte diversity and abundance in streams under different anthropogenic influences in Buea, southwestern Cameroon. Floristic surveys were carried out using 500 m long transects laid along the different streams. Plants encountered were identified and confirmed at the Limbe Botanic Garden Herbarium. One hundred and ten species belonging to 38 families and 83 genera were recorded. There were no floating species and only one stream had submerged species (Vallisneria spiralis L and Crinum calamistratum Bogner & Heine). The highest number of families (26), genera (58) and species (70) were obtained in Ndongo while the least of these taxa were obtained in Bulu (16, 35 and 39, respectively). Overall, Asteraceae and Poaceae were the most abundant, suggesting anemophilic dispersals. However, individual species abundances varied with streams. The highest diversity index (0.945) was in Wongangjio while the least (0.760) was in Nange, suggesting that waste discharge from car wash might influence species diversity negatively. The macrophyte composition was made up of obligate and non-obligate species as a consequence of anthropogenic influences. These results constitute baseline data for the area that can be exploited for further research and monitoring.

Mangrove forests are among the most productive natural ecosystems in the world and offer invaluable ecological functions, yet are seriously threatened. Anthropogenic activities within mangroves can cause alteration of physicochemical parameters of sediments which in turn affect the assemblage of biological communities. This study was designed to assess the impact of anthropogenic disturbances within the Tiko mangroves on the benthic algal community. Perturbations were assessed through questionnaires. Two sets of composite sediment samples were collected for physicochemical and algal analyses from seven sites within the mangroves following standard methods. Seven drivers of change were identified (agriculture, human settlement, logging, fuel wood collection, fishing, fish smoking and petty trading) as the main perturbations of the ecosystem. A total of 141 benthic species were identified at the different sites. The Bacillariophyta were the most abundant with 60 algal species followed by Chlorophyta with 38 algal species. The most dominant species were Chlorobotrys regularis (50) and Microcytis sp (38).Site 3 (settlement site) was the most diversed with 72 species. The mean abundance of benthic algae ranged from 0.59 ± 0.17 to 2.08 ± 0.58. High concentrations of nutrients and the presence of Bacillariophyta and Microcystis suggest pollution. There is a need to monitor activities carried out around the mangrove ecosystem with respect to quantity and quality of waste discharged into the environment since this is a highly sensitive environment.

Pot experiments were carried out to evaluate the effects of supplementing soil nutrients with different levels each of NPK (20:10:10) and poultry manure on the growth and biomass production of Roselle (Hibiscus sabdariffa L.). Soil supplemented with 20 ton ha -1 poultry manure significantly ( = 0.05) increased growth, partitioning over 80 % of dry weight to shoots. Treated plants flowered at 10 weeks after sowing. Anthocyanin was more concentrated in the leaves of plants treated with chemical fertilizer than in manure-treated and control plants, but the trend reversed at 18 weeks. It was concluded that 20 ton ha -1 poultry manure significantly increased growth, biomass, and economic yield of Roselle.

Phytoremediation is a cheap and environmentally friendly technique in which green plants in situ are used to clean the soil, sediments and water of heavy metals. This study investigated the phytoremediation potential of six naturally occurring macrophytes from Nange (a stream in Buea municipality where cars have been driven into and washed for over 20 years). Plant samples were collected before and after car wash, then analysed for copper, zinc, lead and cadmium accumulation. There was an increase in concentration of all the four heavy metals in water after carwash point, with Zn having the highest concentration (0.27 mg/L). Mean concentration of the heavy metals in the water showed that Zn and Pb had the highest concentrations (0.24 mg/L each) while the least concentration was obtained in Cu (0.12 mg/kg). Heavy metal concentrations in the sediments were higher after car wash point than before. Cadmium had the highest concentration (5.58 mg/kg) while Cu had the least (0.75 mg/kg). Ludwigia peruviana had the highest BAFs for all the heavy metals (22.95 for Cu, 33.41 for Zn, 21.79 for Pb and 7.85 for Cd).Species with the leasts were: Anubias barteri for Cu (7.16), Polygonum persicaria for Zn (14.28), Rorippa nasturtium-aquaticum for Pb (11.60) and Vallisneria spiralis for Cd (1.98). L. peruviana had the highest BAC values (Cu = 10.11, Zn = 14.73, Pb = 11.39, Cd = 3.85) and BCF values (Cu = 12.84, Zn = 18.67, Pb = 10.40, Cd = 4.00). A. barteri had the highest TF (Cu = 1.49, Zn = 1.27, Cd = 1.99) except for Pb where both A. barteri and L. peruviana each had a TF of 1.10. While all the six plants were found to be good accumulators of the heavy metals, L. peruviana showed remarkable efficiency indicating that the species is a good candidate for cleaning such environments. # This article is dedicated to the loving memory of Afui M. Mih who passed away before this article was published.