Sea urchin microbiomes vary with habitat and resource availability

Sea urchins are key grazers in coastal seas, where they can survive a variety of conditions and diets, enhancing their ecological impact on kelp forests and other ecosystems. Using 16S rRNA gene sequencing, we characterized bacterial communities associated with guts of the two dominant sea urchin species in southern California, the red urchin Mesocentrotus franciscanus, and the purple urchin Strongylocentrotus purpuratus. Our results show that the two urchin species have distinct gut microbiomes that vary with habitat. The taxonomic composition of their microbiomes suggests that they may facilitate digestion of food and be a source of nutrition themselves. These results highlight the role of microbiomes within macroorganisms as an extended ecological trait, and suggest that microbes may be crucial to resource use and partitioning in co-occurring species.

Automated summary

Sea urchins are important grazers in coastal seas, and through studying the gut microbiomes of two dominant species in southern California, it was found that they have distinct microbial compositions which may aid in digestion and act as a source of nutrition. This highlights the role of microbiomes as an extended ecological trait within macroorganisms and suggests that microbes play a crucial role in resource use and partitioning in co-occurring species.