The Australian Ocean Microbiome (AOM) project, and the Australian Marine Microbial Biodiversity Initiative (AAMBI) are two ongoing initiatives that aim to elucidate the composition of microbial communities in Australian marine provinces over long-term temporal and large spatial scales. The AOM, a cruise-based endeavor, combines high-resolution lagrangian sampling with large spatial transects. The AAMBI aims to establish a sustained microbial sampling program at the nine coastal marine National Reference Stations of the Integrated Marine Observing System (IMOS). Both projects use standardized sampling and sequencing methods, and, to-date, have resulted in a combined dataset comprising > 600 samples and > 10 million 16S rRNA sequence reads. This data cover multiple depth profiles from the Indian Ocean and the Arafura, Timor, Coral and Tasman Seas, along with time-series data from ~5 years at the Port Hacking NRS in NSW and 1 year at Maria Island, Tasmania and North Stradbroke Island, Queensland. I will discuss preliminary patterns emerging from this dataset, such as highly repeatable seasonal cycling in diversity and community composition. I will also discuss recent efforts to describe ecologically relevant units of selection and to employ species distribution modeling to predict microbial geographic range profiles.