Mediterranean aegagropiles from Posidonia oceanica (L.) Delile (1813): a first complete description from macroscopic to microscopic structure

摘要: Aegagropiles are round-shaped conglomerations of Posidonia oceanica debris commonly found along the coasts Mediterranean Sea. This study presents a detailed description composition aegagropiles in terms their internal organisation different layers (and orientation fibres these layers), proportion constituent elements (fibres and minerals) histological (by way microscopic observations) nature all elements. The aim this work is to take interest structure determine process that forms them. an assemblage two types from P. meadow: (1) plant-based: more or less degraded shoots (leaves rhizomes) (2) mineral particles such as silicates biotic Ca-carbonate debris. On basis structural compositional observations, we proposed elucidation cycle several phases: initiation “roll” by aggregation litter sand ripple marks, growth, breakdown roll into small balls (microbial mechanical degradation) export down (into abyss) on beaches. Calculations estimate considering its density 0.2 g/cm3, aegagropile represents accumulation approximately 25 oceanica.