Résumé
Les observations limnologiques régulières dans la partie Sud du Lac Volta révélaient des changements significatifs dans la transparence, la couleur, la quantité totale de fer et l'oxygène dissout pour la période de 1965 à 1966 mais rien de semblable pour celle de 1966 à 1967. Ces facteurs montraient aussi des corrélations si significatives que beaucoup d'entre eux pouvait être estimé à partie de la simple mensuration de la seule transparence. La densité de phytoplancton ne changeait pas de manière significative que ce soit de 1965 à 1966 ou de 1966 à 1967. Toutefois, les principaux constituants passaient par une série de changements allant des algues vertes (Actinatrum) au début de 1965, aux flagellates (Cryptomonas et Peridinium) de 1965 à 1966 puis aux diatomées (Nitzschia et Synedra) de 1966 à 1967. La densité de phytoplancton presentait une corrélation significative uniquement avec l'oxygène dissout duquel il pouvait être grossièrement estimé.
Summary
Regular limnological observations at the lower reaches of the Volta Lake revealed significant changes in the transparency, colour, total iron and dissolved oxygen from 1965 to 1966 but not from 1966 to 1967. These factors also showed correlations of such a significance that many of them could be estimated from a simple measurement of the transparency alone. The density of phytoplankton did not change significantly either from 1965 to 1966 or from 1966 to 1967. The chief constituents, however, passed through a series of changes from a green alga (Actinastrum) in early 1965, through the flagellates (Crytomonas and Peridinium) during 1965–1966, to the diatoms (Nitzschia and Synedra) during 1966–1967. The density of phytoplankton correlated significantly only with the dissolved oxygen from which it could be roughly estimated.
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Biswas, S. Ecology of Phytoplankton of the Volta Lake. Hydrobiologia 39, 277–288 (1972). https://doi.org/10.1007/BF00047189
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DOI: https://doi.org/10.1007/BF00047189