NanoSIMS data from sponges collected in Summerland Key in Florida between July 27 - August 19, 2021

Sponges represent one of the oldest extant animal phyla, and their associations with microbial symbionts have likely played a critical role in their success on oligotrophic coral reefs. For example, variation in the abundance, diversity, and community composition of microbiomes across host species may drive niche partitioning due to differential assimilation and recycling of nutrients across sponge species. With Nanoscale secondary ion mass spectrometry (NanoSIMS), we evaluated the respective roles of host and microbial symbiont cells in the uptake and recycling of three resource pools (dissolved organic matter: DOM, particulate organic matter: POM, and inorganic nutrients: NaHCO3 and NaNO3) over 72 hr. NanoSIMS analysis revealed enrichment of individual host and symbiont cells over time and highlighted the differing roles of host and symbiont cells in the uptake and recycling of diverse sources of carbon and nitrogen within two of these species. For instance, dissolved organic matter uptake was mediated by microbial symbionts in one species and by host cells in another species. Together , these results demonstrate that associations with microbial symbionts have facilitated niche partitioning by allowing host sponges to acquire and recycle diverse nutrient pools via unique mechanisms. Field and lab work for this research was carried out in the Florida Keys during June/August of 2021.