Several studies have assessed the effects of the released oil on microbes, either during or immediately after the Deepwater Horizon accident. However, little is known about the potential longer-term persistent effects on microbial communities and their functions. In this study, one water column station near the wellhead (3.78 km SW of the wellhead), one water column reference station outside of the affected area (37.77 km SE of the wellhead), and deep-sea sediments near the wellhead (3.66 km SE of the wellhead) were sampled one year after the capping of the well.