Abstract
The rotifer populations of the algae of a large marine lagoon (the Fleet, which lies behind Chesil Beach, Dorset, England) were assessed from 1993 to 1998. Physical and chemical parameters were measured at different sites, including water and air temperatures, pH, and the ions NH4+, NO3-, PO43- and SiO44-. Significant differences were found between species, species richness and total abundances with both spatial and temporal variations. Granularity of some sites was measured. A new method of assessing water disturbance is described, using the loss of dye across a low-permeability membrane. An inverse correlation was found between on one hand species richness and total abundances, and on the other salinity. Some possible reasons for the distribution found include salinity, temperature, and the relationships between the morphology of the algae present and the rotifers’ behaviour and preferred habitat, with particular respect to the foot of Testudinella clypeata. Significantly larger populations of Proales reinhardti were found in the littoral pools containing mainly phaeophyte algae, than in those containing mainly chlorophyte algae. Laboratory experiments showed that sustained high temperatures are the probable cause of the populations of P. reinhardti in the littoral pools falling in late Spring. The identification and taxonomy of the species found are discussed. A new species - Proales fleetensis nov. sp. is described. This thesis also presents some approaches to overcoming the difficulties of quantitative sampling of littoral rotifers.