The sponge microbiome within the greater coral reef microbial metacommunity

Area of Science:

• Marine microbiology
• Coral reef ecology
• Microbial ecology

Background:

• Marine microbial research has increasingly focused on sponges.
• The integration of sponge microbiomes into the broader coral reef microbial metacommunity remains poorly understood.

Purpose of the Study:

• To conduct an extensive survey of prokaryote communities across diverse Indo-Pacific coral reef biotopes.
• To investigate the specificity and environmental sharing of sponge-associated prokaryotes.

Main Methods:

• Survey of prokaryote communities in various coral reef biotopes (sponges, algae, corals, sea cucumbers, chitons, sediment, seawater).
• Analysis of operational taxonomic unit (OTU) richness and shared OTUs across different biotopes.
• Phylogenetic analysis to identify dominant microbial groups, including Planctomycetes.

Main Results:

• Significant variation in OTU richness was observed, with algae, chitons, stony corals, and sea cucumbers exhibiting the most diverse prokaryote communities.
• These diverse biotopes shared a higher percentage and number of OTUs with sediment and were enriched in Planctomycetes.
• Sponges, despite lower OTU richness, shared over 90% of abundant OTUs with the surrounding environment (sediment and/or seawater), with notable interspecies variation.

Conclusions:

• Prokaryote microorganisms are shared among multiple coral reef biotopes.
• The sponge prokaryote community, while compositionally distinct, is not as sponge-specific as previously assumed.
• This study enhances understanding of microbial exchange and community structure within coral reef ecosystems.