M.S. Biological Sciences
Jose V. Lopez
Diverse and ecologically important microbial communities (microbiomes) are symbiotic within marine sponges. In this study, the microbiome of Amphimedon compressa from three sample locations (Broward and Dade Counties, Southeast Florida, USA and the Southern Caribbean, Bocas del Toro, Panama) is characterized using 16S rRNA Illumina sequencing. The predominant taxa are Proteobacteria and Cyanobacteria, as expected for Low Microbial Abundance sponges, accounting for over 53% of the total microbiome community. The numbers of Operational Taxonomic Units (OTUs) decrease from Broward County (2,900) to Dade County (2,300) and then Bocas del Toro (1,200). The correlates to a decreasing north-south gradient of sponge microbiome richness and diversity. Sponge microbiome richness and Alpha diversity are nearly identical from the two closest locations (37 km), both in Southeast Florida (Tukey HSD/ANOVA; p=0.999). However Panama sponge microbiome richness and Alpha diversity are distinctly lower, with the primary driver being distance, ~1,850 km from Southeast Florida. Abiotic factors driving this trend of decreased richness and diversity include increased temperature, and deceased salinity in relation to precipitation-based seasons. Sponge microbiome Beta diversity as determined by Bray-Curtis Dissimilarity and Non-Metric Multidimensional Scaling documents the clustering of Panama samples as distinct from the Broward and Dade County samples. In a seasonal comparison, Broward County sponge microbiome richness (p=0.026, r2=0.92) and Alpha diversity (p=0.007, r2=0.98) are significantly different, documenting robust effects of temperature. This comparison confirms lowest microbiome OTU diversity in the season with highest precipitation and highest temperatures of 29.8 °C. These results are consistent with prior studies that report decreasing microbiome OTU richness and diversity under conditions of environmental stress such as decreased salinity and increased temperatures.
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Renee Michelle Potens. 2016. Characterization of the Marine Sponge Amphimedon compressa Microbiome Across a Spatial Gradient. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, . (413)
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