Background/Question/Methods The National Ecological Observatory Network (NEON) is a national-scale research platform for analyzing and understanding the impacts of climate change, land-use change, and invasive species on ecology. NEON features sensor networks and experiments, linked by advanced cyberinfrastructure to record and archive ecological data for at least 30 years. Using standardized protocols and an open data policy, NEON will gather essential data for developing the scientific understanding and theory required to manage ecological challenges. NEON data will be gathered from the level of the gene and organism to populations and communities, which shall be extrapolated to the continental scale. The scaling strategy requires a mixture of human and instrumental measurements. The Fundamental Sentinel Unit is responsible for the field observations and analyses of biological specimens that will provide data on biodiversity, population dynamics, productivity, phenology, infectious disease, biogeochemistry and ecohydrology. The observatory will track patterns in communities including: microbes, plants, algae, insects, aquatic invertebrates, birds, fish and small mammals. Results/Conclusions The FSU design is intended to reflect the best available science, be compatible with existing programs, be flexible across a range of environmental gradients, and facilitate research across a broad range of areas. FSU measurements will be standardized across all NEON sites and, wherever possible, sampling will be co-located across taxa. The data collected by the FSU will enable research across several disciplines. Here we present a few examples of the type of research NEON will enable using FSU data including infectious disease, invasive species, phenology, and ecohydrology.