Spicules are the ” bricks of sponge architecture.” And as i quote ” architecture is the biggest fractal system”, thus this structure of sponge also exhibits magnified fractal pattern as structural inspiration for some architectural buildings. Few world renowned architects have used sponge structure and research is still going on as the expected result is stable and very strong geometry for architecture.The exoskeleton of sponges (so, the parts that you see) are composed of a mixture of spongin and/or spicules.
Spongin is a modified type of collagen protein, and forms the “fibers” or “mortar” that hold spicules together. Generally, species are identified based on the presence or absence of spongin in a sample
In sponges, spicules are structural elements that provide support and rigidity to their bodies. They are often composed of either silica (siliceous spicules) or calcium carbonate (calcite or aragonite spicules). The type of spicules present in a sponge species can be used as a characteristic feature for identification and classification.
Siliceous Spicules
Siliceous spicules are the most common type of spicules found in sponges. These spicules are composed of silica, which is a hard and durable mineral. Siliceous spicules can take various forms, such as needle-like, rod-like, star-shaped, or even more intricate shapes. Different sponge species have distinct types of siliceous spicules, allowing scientists to differentiate between them based on spicule morphology.
Calcite Spicules
Some sponges have spicules made of calcium carbonate, specifically in the form of calcite. These calcite spicules are usually needle-like or rod-like in shape. Examples of sponges with calcite spicules include some species within the class Calcarea.
Aragonite Spicules
Another form of calcium carbonate spicules found in sponges is aragonite spicules. These spicules, composed of the mineral aragonite, can also be needle-like or rod-like. Sponges with aragonite spicules are typically found in shallow tropical waters.
It’s important to note that not all sponge species possess spicules. Some sponges lack spicules altogether and instead rely on a protein-based matrix called spongin for structural support. Sponges that lack spicules and have a body composed primarily of spongin are referred to as “sponginous” sponges.
The study of spicules, their morphology, and their distribution among different sponge species is valuable for taxonomic classification and understanding the evolutionary relationships between sponge groups. Spicules can be analyzed through microscopic examination, and their characteristics contribute to the identification and classification of sponge species.