A Clionid Overview with Regards to Biology, Abundance, and Distribution: Including a Comparison of Case Studies of Symbiosis, Bioerosion, and Eutrophication

Sponges from the phylum Porifera, Latin porus, “pore”; ferous, “bearing”(Borror 1988) are essential yet often overlooked in coral-reef ecosystems. Marine sponges are among the oldest, structurally simplest multicellular sessile animals that bridge the gap between single celled organisms (protists) and more complex Metazoans (Kaplan 1988, Taylor et al 2007). Although they lack complex tissues and organs seen in higher Metazoa, they are nevertheless a highly successful group of animals due to their aquiferous filtering system, cell totipotency, and plasticity of their body (Brusca and Brusca 2003). As a prolific producers of bioactive metabolites, they have considerable ecological importance due to their abundance and ability to filter enormous volumes of seawater (Taylor et al 2007). In each section of this report, I will discuss a topic relating to all sponges, dive further into explination specifically for Clionid sponges, and lastly compare two case studies for the topic involving Clionids exclusively. The aim of this review is to examine recent developments in the understanding of a variety of sponge aspects and to help others understand basic sponge biology and lifestyles while further explaining why Clionid sponges specifically are of importance and how they impact the worlds oceans. A coral reef is a tropical shallow-water photosynthetic scleractinian coral community colonized and strongly affected by octocorals, algae, and other invertebrates such as sponges, that secrete calcium carbonate (Rutzler 2004). The entire reef system operates through different animal-plant symbioses which construct limestone through secretion and cementation (Rutzler 2004). The health of different coral reef communities have been attributed to how fast limestone is created versus eroded within certain vicinities, along with many other factors. Sponges participate in all aspects of these processes thus playing an especially important role (Neumann 1966, Diaz and Rutzler 2001, Rutzler 2004). Rutzler (2004) claims that modern sponges can no longer be solely included with coral reef framework builders because they clearly impact the coral reef stabilization as well as its destruction due to the major processes of bioerosion and lithification (Goreau et al. 1979). After Diaz and Rutzler (2001) studied sponge diversity, abundance, productivity and nutrient cycling from Carrie Bow Caye on the barrier reef in Belize, they explained that sponges have multiple properties that make them influential part of coral reef ecosystems. These characteristics include high diversity, high abundance, calcification capabilities, acting as primary producers of nitrification through symbioses, having different chemical and physical adaptations for space competition with the potential to change the chemistry of the water column. Sponges are of particular interest in the medical field and researchers have looked specifically at the sponge-bacteria relationship as a possible source of natural medicines after isolating antimicrobial compounds (Stierle and Stierle 1992, Imamura et al 1993, Jayatilake et al 1996, Bultel-Ponce et al 1997, Webster et al 2001b). Also, many sponges produce and release antibiotics that play a role in their own defense by warding off hungry predators, being encroached on by aggressive neighbors, or overgrown by fouling organisms. (Ruppert and Fox 1988, Stierle and Stierle 1992, Imamura et al 1993, Jayatilake et al 1996, Bultel-Ponce et al 1997, Webster et al 2001b). Recently, a collection of important bioactive compounds have been discovered as antibiotics in sponges, many having potential pharmacological significance (Brusca and Brusca 2003). Specifically, two different Clionid species; Cliona celata (Keyzers et al 2008), Cliona patera (Sawangong et al 2008). I will not discuss these in this report, but they are noted for completeness sake. The discovery of these natural products in sponges has led to a renewed interest in and a desire to understand sponges. Sponges of the family Clionidae have long been known for the ecological impact they cause by riddling limestone objects which they inhabit in most marine environments (Rutzler 1975). Clionid sponges are one of the most important framework bioeroders on coral reefs. They have the ability to out compete stressed corals, so any dramatic increases in the area or abundance of these sponges could lead to an increase in the breakdown of the reef framework and reduce the opportunity for reef recovery (Callahan et al 2005). They are extremely strong reef space competitors aggressively undermining and displacing live coral tissue (Rutzler 1975, 2002a; Lopez Victoria et al 2003, Lopez-Victoria & Zea 2005). Researchers also find boring sponges of importance when reconstructing paleoenviromental records by measuring the size of bore holes in reefs compared to the geological record (Edinger and Risk 1996, Zundelevich et al 2007)