Utilizing sponge spicules in taxonomic, ecological and environmental reconstructions: a review

Abstract

Most sponges produce skeletons formed by spicules, structural elements that develop in a wide variety of sizes and tridimensional shapes. The morphologies of spicules are often unique to clade- or even species-level taxa which makes them particularly useful in taxonomic assignments. When dead sponge bodies disintegrate, spicules become incorporated into sediments and sometimes accumulate into enormous agglomerations called spicule mats or beds, or fossilize to form special type of rocks called the spiculites. The record of fossil and subfossil sponge spicules is extraordinarily rich and often serves as a basis for far-reaching reconstructions of sponge communities, though spicules are also bearers of significant ecological and environmental information. Specific requirements and preferences of sponges can be used to interpret the environment in which they lived, and reconstruct oscillations in water depths, pH, temperatures, and other parameters, providing snapshots of past climate conditions. In turn, the silicon isotope compositions in spicules (δ30Si) are being increasingly often used to estimate the level of silicic acid in the marine settings throughout the geological history, which enables to reconstruct the past silica cycle and ocean circulation. This contribution provides a review of the use of sponge spicules in reconstructions of sponge communities, their ecology, and environments, and aims to detect the pertinent gaps in their utilization. Even though spicules are well known for their significance as bearers of taxonomic, ecological, and environmental data, their potential remains to be fully exploited.

A 36,200-year-old carving from Grotte des Gorges, Amange, Jura, France

“…The 3D reconstruction shows it is filled with thin, homogenous sediment containing randomly oriented tubular features (SOM Data S1 ). These features are identified as spicules of fossil sponges, some of which taking the form of 4-pointed stars 44 , 45 . This observation and consideration of its outer morphology indicate the object is a fragment of an ammonite inner mold consisting of a partially preserved septum of the phragmocone.…”

Solid State Fermentation of Shrimp Shell Waste Using Pseudonocardia carboxydivorans 18A13O1 to Produce Bioactive Metabolites

“…Sponge 18A13 (Figure 2) was shaped like a ball with reddish-purple exterior color, and yellowish internal color. This sponge has long tubular spicules with two pointed ends, characteristic of Demospongiae [19]. It was identified as Rhabdastrella globostellata, which is common along the Indonesian coast.…”

A morphological guide of neotropical freshwater sponge spicules for paleolimnological studies

“…Similarly, freshwater sponge spicules preserved in lake sediments have been used as ecological tools in paleoenvironmental studies (Harrison, 1988). Since then, significant progress has been made by applying freshwater sponge spicules to answer paleoenvironmental, paleoecological, evolutionary, and taxonomic questions (Pronzato et al, 2017;Łukowiak, 2020;Docio et al, 2021;Łukowiak et al, 2022).…”

“…However, few guides for sponge morphology are available to assist researchers and students, which presents a roadblock to fully gaining insights into paleoecology and paleolimnology from these fossils. A few studies are available on the use of sponges as a proxy in paleoenvironmental studies (Docio et al, 2021), taxonomy, geographic distribution, and critical review of the fossil freshwater sponges (Pronzato et al, 2017;Łukowiak, 2020), and more recently the terminology of sponge spicules (Łukowiak et al, 2022). This stands in contrast to those available 10.3389/fevo.2022.1067432 for other siliceous microfossils such as diatoms and phytoliths (e.g., Neumann et al, 2019;Spaulding et al, 2021).…”