Distributions of rare earths and heavy metals in field-grown maize after application of rare earth-containing fertilizer

Macroalgal blooms have been considered to be an indicator of eutrophication. A new and rapid method is described for the assessment of macroalgal cover in the intertidal zone of estuaries. Macroalgal cover in the intertidal of the nutrient-enriched River Deben estuary was found to reach a maximum of 50% coverage, but this varied seasonally with the highest percentage cover during June and July. Macro-algae mats were particularly associated with areas of hard substrata providing suitable attachment points, rather than with the nutrient concentrations along the estuary. The occurrence of macroalgae may be more related to the substrate than to the nutrient status of the estuary.