Arctic Seas are among the fastest changing ecosystems on earth, with potentially vast implications for ocean health and its various services provided to humans. Predictions of the Ocean’s future will depend on the understanding of the status quo, including detailed knowledge of the Ocean’s diversity. This proposal will fill the major gap in our current understanding of Arctic Ocean biology. Microbes in general have been largely ignored in marine science, specifically in polar seas, with their wealth of charismatic megafauna. We propose to establish ‘metagenomic maps’ of Arctic microbial communities associated with sea ice, sediment, and host-associated communities to enable further discoveries of their diversity, ecological importance, and usefulness. Historically, the exploration of Arctic marine microbes has advanced at a pace comparable to mapping the seafloor using a sounding line – one hard-won data point at a time. New technologies are disrupting traditional approaches to marine microbiology and have opened up vast new expanses of biodiversity to our exploration – if we are willing to make the voyage. The rapid decline in Arctic sea ice gives further impetus to the importance of acting now. Our approach will combine 19th century collection of sea ice and sediment samples with 21st century next-generation analysis tools.