Les sédiments d'un lac de haute montagne: Structure, nature et peuplement

Abstract

The vertical variations of physical and faunistic components in cores of sediment samples from the profundal zone of lake Port-Bielh (Central Pyrenees) were analysed. These sediments are particularly fine (100 % < 50 µ) and muddy. Their structure is formed by constant suspension and decantation as well as through the activity of benthic organisms. The nature of the sediment does not reflect the chemical composition of the surrounding basin, but is the product of an important movement of ions in solution.The maximal population density is found in the superficial layers but the vertical distribution varies among groups. The modalities of these distributions are described. © 1974 Masson.