ALOHA Observatory

In 2002, the National Science Foundation funded a Major Research Instrumentation proposal from the University of Hawaii to design, construct and emplace infrastructure for a cabled ocean bottom observatory at Station ALOHA, a long-term, deep-ocean research site 100 km north of Oahu. Station ALOHA has been the location of ~monthly shipboard observations of water column physics, biogeochemistry, and ecosystems for over 18 years under the Hawaii Ocean Time-series (HOT) Program. During a five-day cruise, the 513-foot US Navy cable repair ship Zeus cut and recovered the retired HAW-4 electro-optical telecommunications cable, pulled aboard 20 km of cable, laid it back out to Station ALOHA, spliced the cable to the ACO cable termination frame, tested the system, and lowered the frame and Proof Module to the ocean floor in 4,700 m of water. At 3:00 AM, February 16, 2007, an acoustic release was fired, allowing the ALOHA Cabled Observatory (ACO) to settle to its new home on the ocean floor at Station ALOHA. Within minutes, observers at the AT&T Makaha Cable Station were listening to humpback whale song, inaugurating the beginning of data collection from the ACO. The Proof Module of the ACO is to remain operational in this configuration through October.

In early November 2007, the Proof Module is to be recovered and replaced with the full observatory module, using the Remotely Operated Vehicle (ROV) JASON II operating from University of Hawaii’s Research Vessel Kilo Moana. It will take several dives with JASON to install the full observatory infrastructure where the Proof Module is now plugged in. The full observatory will have eight connectors on it to power and supply a 2-way data path to for up to eight experiment systems. The Proof Module will then be cut free by JASON to float to the surface where it will be recovered and re-configured into an experiment to be plugged back into the ACO.

After the full installation of the ALOHA Cabled Observatory, periodic cruises to Station ALOHA will still be required to obtain water samples, to provide broader spatial coverage, and to install new systems at the observatory. Hower, the capabilities of the observatory will greatly expand the opportunities for research by allowing data from subsurface instruments to be retrieved continuously, to allow commands to be sent to the instruments to modify their sampling, and by providing power to instruments thus extending their duration. The ALOHA Observatory will provide power and broadband communications capability necessary for real-time continuous monitoring of the ocean environment for at least a decade. These capabilities will also support short-duration, state-of-the-art experiments.

Investigators from institutions around the world are encouraged to propose additional infrastructure and individual experiments. For example, a project led by UW/APL is developing cabled-moored-profiler infrastructure that will extend the reach of the ALOHA Observatory (and the Internet itself) from the seafloor to the ocean surface. Observatory investigators will be able to monitor their experiments and modify them remotely as conditions warrant via Internet connection. Web access will allow students and the public to observe the ocean alongside the researchers.

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This material is based upon work supported by the National Science Foundation under Grant No. OCE 0330294. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.