capítulos de libros
Epipelic biofilms as indicators of environmental changes in lowland fluvial systems
GÓMEZ, NORA; SIERRA, MARÍA V.; COCHERO, JOAQUÍN; LICURSI, MAGDALENA; BAUER, DELIA E.
Biofilms: Formation, development and Properties
Nova Science Publishers
Año: 2011; p. 260 - 290
The epipelic biofilm is a biologic complex of autotrophs (algae) and heterotrophs (fungi, bacteria, microinvertebrates) embedded in a polysaccharide matrix that develops on the fine sediments (silt and clay) of many aquatic ecosystem worldwide of lowland fluvial streambeds. Biofilms play a key role in the energetic balance of the fluvial systems, contributing to the recycling of organic matter and, therefore, to their self-depuration. The structure and function of a biofilm are affected by a variety of factors, both natural and anthropogenic, that, in turn, determine the physical and chemical conditions of the water. The characteristics of biofilms on episammic and epilithic substrates have been widely described in the literature, but the features of epipelic biofilms have been only scarcely documented. In this chapter, we present a review of the use of the structural and functional parameters of epipelic biofilms in order to assess changes in water and habitat quality as a result of human impact. Methodologies for the sampling and analysis of biofilms are described; and selected study cases are discussed in order to provide information about specific composition, density, biomass, biological indices, primary production, respiration, and enzymatic activities of the epipelon in relation to different uses of the surrounding land. The structural and functional parameters of biofilms should be made an integral component in the routine assessment of stream health as well as in the establishment of baseline values for both disturbed and undisturbed systems to be incorporated into monitoring and compliance guidelines.