Interdisciplinary time series observations are important for understanding and predicting ocean variability on time scales from seconds to decades. Plans are being made to implement open ocean observatories at key sites in the world ocean (e.g., OceanSITES and ORION). The Bermuda Testbed Mooring (BTM), located southeast of Bermuda (BATS site), and the HALE-ALOHA (H-A) mooring, north of Hawaii (HOT site) are prototypes for autonomous sampling interdisciplinary open ocean observatories. Both moorings are located in the deep sea (over 4500 m water depth) and provide fundamental measurements of meteorological, physical, biogeochemical, biological, and optical variables. Many of the present national and international ocean observatory plans have benefited from BTM and H-A research and development. Both programs provide stimuli for many forward-looking ideas concerning ocean technologies and the synergistic use of observations and models. New measurement systems and scientific results from the BTM and H-A projects are leading to improved sampling relevant to global biogeochemical cycling, ecosystem dynamics, and climate change as well as to improved predictive modeling in these areas along with air-sea interaction and hurricanes