Over the course of two years of C-DEBI support, I have investigated subseafloor microbial ecology in three separate environments; the basaltic crust aquifer underneath the sediments of North Pond, the sediments of North Pond, and the sediments of the Iberian Margin at IODP site U1385. At North Pond, my research was primarily cultivation-based, with enrichments for multiple metabolisms across basalt and sediment samples. Shallow and deep heterotrophic isolates from the sediment column at site U1382B offer an opportunity to ask unique research questions regarding the breakdown of fresher, more labile organic carbon vs. older, more refractory organic carbon. At the Iberian margin, my research was primarily molecular-based, with several enrichment and cultivation efforts initiated after compelling evidence for particular metabolisms associated with individual groups of microbes. Diversity studies using high-throughput sequencing of 16S/18S rRNA amplicons examined the distribution and abundance of bacteria, archaea, and microbial eukaryotes. To further investigate ecological trends and the biology of particular community members, metagenomes were generated from the same DNA pools as the amplicon data.