Microorganisms in exposed sandy beaches: importance, methodological aspects and state of art for the southem Brazilian coast

Abstract

We adopt a wide concept of marine microorganisms (bacteria, microalgae, protozoan, fungi, and virus), and present their general characteristics, controlling factors and information on the role of these organisms as primary producers, mineralizers and consumers. Methodological aspects regarding the sampling program, sample conservation, counting and biomass estimation are also discussed. At the exposed sand beaches of the southern Brazilian coast, high primary production occurrs due to surf zone diatom accumulation. This is a poorly studied phenomenon, and detailed research is necessary in order to quantify the production and consumption processes, and to determine the fate ofthe organic matter produced in these environments. Key-words: diatom, protist, bacterium, microbenthos, surf-zone, southern Brazil