Aspects of the spatial distribution of the algae of the nant-y-moch reservoir,Ceredigion, Wales

The spatial distribution of algae in the Nant-y-Moch reservoir has been studied in relation to a number of factors. It was not possible to relate the variation in algal numbers to the wind parameters studied and it is postulated that water currents, set up by the abstraction of water, may be influencing the distribution. The variation of species composition in the different parts of the lake was summarised by means of diversity and heterogeneity indices. It was found difficult to relate the differences in diversity indices to the position of the transects sampled; which again was probably the result of the complex water patterns likely to exist in the lake. Average mean heterogeneity indices indicated that four transects were relatively different from each other and from the other transects studied; reasons for the differences are suggested.