Biomineralization: Sponge Spicules and Skeletons

This lecture explores the biomineralization process in sponges, focusing on the diversity of spicules and the structural organization of their skeletons. It covers the classification of sponges, the composition of spicules (silica and calcium carbonate), the role of organic fibers like spongin, and the genetic determination of spicule shapes. The lecture also delves into the intricate process of spiculogenesis, the localization of spicules, and the unique properties of sponge skeletons. Additionally, it discusses the hypercalcified sponges, their massive basal skeletons, and the potential environmental archive they provide. The study of elemental and isotopic ratios in sponge skeletons offers insights into paleotemperatures and changes in oceanic calcium concentrations.