Ecophysiological perspectives of blue-green algal blooms

Blue-green algae (cyanobacteria) have had a profound and unparalled impact on the aquatic environment because of the phenomenon of bloom formation. In many countries, water management is threatened with extensive and persistent noxious blooms of blue-green algae in surface and near-surface mesotrophic and eutrophic waters. In view of this, ecological and physiological factors responsible for blue-green algal dominance are discussed. The implications of cyanobacterial blooms are highlighted and recommendations made to combat this menac

Productivity estimation of Ologe Lagoon, Lagos

One of the paradigms in the management of fish resources is that annual yield is a function of water quality. Consequently, the use of shorthand methods for predicting yields from morphological and /or edaphic factors of the water body are most appropriate for tropical multi-species fisheries. In this study, the morpho-edaphic index (MEI) was used to estimate the productivity of Ologe lagoon (Nigeria). The predicted yield was 73.8 kg ha super(-1) yr super(-1) and a comparison with yields in other African waters showed that Ologe lagoon is highly productive. However, its potential is not fully harnessed due to the traditional nature of the fishin

Cumulative impact of effluents on plankton dynamics in Awba Reservoir, Ibadan

The assessment of changes in the biological community of water is a very sensitive measure of its quality. The plankton community structure of Awba reservoir in the University of Ibadan, Nigeria was monitored between April and October 1989 to determine the impact of natural eutrophication and effluent discharge on its dynamics. Generally, the dissolved oxygen content, pH, conductivity and ammonia-nitrogen values indicated a deterioration in water quality at stations receiving organic or chemical effluents. The plankton structure was characterized by a blue-green algae - Protozoa dominated community. The Simpson's diversity index at all stations was less than one implying a heterogeneous community where a few species dominated. Tropical Freshwater Biology VOL. 8 1999, pp. 1-15 KEY WORDS: effluents - water quality - Simpson's diversity index - plankton community structur

Detection and quantification of toxins in cultures of microcystis aeruginosa (pcc 7820) by hplc and protein phosphatase inhibition assayffect of blending various collectors at bulk

Increasing anthropogenic eutrophication in lakes, drinking water reservoirs and coastal waters is a world-wide phenomenon leading to the formation of blooms of toxic cyanobacteria. These pose a significant threat to human and animal health hence the need for sensitive methods for their detection, identification and quantification. This report presents two methods: analytical high power liquid chromatography coupled with photo-diode array detection and protein phosphatase inhibition assay for the analysis of the most frequently encountered cyanobacterial hepatotoxins – the microcystins. Four microcystin variants: microcystin - LR, - LY, - LW and - LF were identified and quantified by HPLC in cells and growth media of cultured Microcystis aeruginosa PCC 7820. The protein phosphatase inhibition assay was used to estimate potential toxicity of cyanobacterial extracts and both methods showed good correlation (R2 = 0.91). Although HPLC provides accurateand specific information on the identity and quantity of each microcystin variant, it is quite expensive. The assay method on the other hand is relatively cheaper and can be modified to measure milligrammequantities of sample on a benchtop spectrophotometer but individual microcystin variants cannot be identifie