Backgrounder: World's Largest Ocean Observatory Nears Completion

THE INFRASTRUCTURE:

Nodes supply power and two-way communications between the instruments and shore-based scientists. The nodes step voltage down from 10,000 volts to 400 volts. The nodes and their yellow trawl-resistant frames (TRF) were designed and built by Alcatel-Lucent with their subcontractors Texcel Technology (London, UK) and L-3 MariPro (Santa Barbara, California). Each node assembly, with TRF, is worth about $5 million, weighs 13 tonnes and is the size of three mini-vans parked together. Six nodes have been built; one is a spare.
Junction boxes control and distribute power from the node to the instruments. They step voltage down from 400 volts to 48, 24 or 15 volts to more than 400 instruments. Each junction box can support multiple instrument platforms, individual instruments and sensors. All 14 junction boxes were designed and built by OceanWorks International in Vancouver, BC.
Spur cables connect nodes to the cable backbone. They can be up to 20 km long.
Branching units split the cable power and communication signals from the main backbone cable through a spur cable to a node.
Repeaters are required at intervals on the cable to maintain the optical signals and prevent data loss. There are five repeaters along the 800-km loop.
The 800-km loop of powered fibre-optic backbone cable was installed on or under the seafloor in 2007. Also installed at that time were 100 km of spur cables leading to node locations. Some of the cable is buried under the seafloor to protect it against trawlers and ship anchors. The cable contains two fibres for rapid data transmission and a copper electrical conductor, and is typically protected by spiral wire “armour” up to 4 cm thick, depending on the seabed conditions.
The cable loop connects to land at UVic’s shore station in Port Alberni, BC. The shore station provides power to the cable network and manages two-way communications and data flow between the subsea cable network and NEPTUNE Canada headquarters at the University of Victoria, 200 km away.
At UVic, a sophisticated data management and archive system (DMAS) collects and archives all data gathered by NEPTUNE Canada instruments and sensors, makes the data available to scientists and the public via the Internet, and allows scientists to remotely control their instruments.

THE INSTRUMENTS:

A wide variety of instruments and integrated instrument platforms have been provided or developed by companies and researchers. Many involve breakthrough technology being used in the field for the first time.
Instruments range from simple temperature probes, to seismometers and hydrophones, to complex multi-instrument systems and remotely operated vehicles equipped with cameras, probes and chemical analysis units. Instruments and sensors will evolve over time, with old instruments being removed and new instruments added.
Developed for NEPTUNE Canada by scientists at Jacobs University in Bremen, Germany, the ATV-sized Bremen crawler, aka “Wally,” is the world’s first Internet-operated deep-sea crawler. It will be used to study gas hydrate deposits by collecting data on temperature, salinity, methane content and sediment and ecosystem characteristics. It weighs 275 kg out of water but only 40 kg underwater due to attached flotation blocks. Its dual tractor treads allow a full range of forward, backward and turning movements. One of its unique features is its control interface, which plugs directly into the web.
The $1-million vertical profiler system (VPS)—NEPTUNE Canada’s largest instrument platform—was developed by Nichiyu Giken Kogyo (NGK) in Japan and consists of a 2-tonne seafloor platform and a tethered float filled with a dozen instruments. A winch in the platform raises and lowers the float through the water column so that the instruments can take measurements at various depths. The VPS is currently at the Marine Technology Centre in Sidney, where it is being tested by NGK technicians prior to deployment.

NEPTUNE CANADA NODE SITES:

Folger Passage – Located on the inner continental shelf near the entrance to Barkley Sound. Instruments will be placed in two clusters—one on a rocky pinnacle that rises up to 17 metres below the sea surface, the other 95 metres down on the seafloor. Studies at the site will look at biological productivity and seafloor communities. It will also support learning opportunities for students, researchers and the public at the nearby Bamfield Marine Sciences Centre.
ODP 889 – Depth 1.3 km. This site on the continental slope is rich in buried gas hydrates. Scientists will monitor changes in the hydrates, particularly in relation to earthquakes, slope failures and regional plate motions. The site name refers to a borehole drilled by the international Ocean Drilling Program, which studies the history of ocean basins and the nature of the crust beneath the ocean floor.
Barkley Canyon – This site—with the node at 650 metres and instruments positioned as deep as 900 metres—is ideal for the study of seafloor ecology and nutrient and sediment transport between the continental shelf, through a submarine canyon and into the lower continental slope. A prominent mid-canyon outcrop of gas hydrates will also be explored. Equipment includes the vertical profiler system and “Wally,” the world’s first Internet-operated deep-sea crawler.
ODP 1027 – Depth 2.7 kms. This is the deepest site, located on the abyssal plain. Here, NEPTUNE Canada connects to existing Ocean Drilling Program borehole monitoring systems to study changes in Earth crust temperature and pressure as they relate to earthquakes and tectonic plate activity. The site will also host a key array in a plate-wide tsunami detection system that uses sensitive bottom pressure recorders to measure tsunami speed, height and direction. The data will complement information gathered by other tsunami sensors around the North Pacific.
Endeavour Ridge – Depth 2.3 kms. This is the most remote site, about 300 km from the BC coast, where new volcanic seafloor is being created at the spreading boundary between the Juan de Fuca and Pacific tectonic plates. A network of seismometers will provide high-resolution information on tectonic processes across the Juan de Fuca plate. Four regional moored instrument buoys extending 250 metres above the seafloor will document the ocean currents and chemical fluxes. Scientists will also observe the unique deep-sea “black smoker” ecosystems that flourish in the main hydrothermal vent field. Note: due to time constraints, instrument deployment at this site will not be completed until 2010.

GENERAL FACTS

To combat the effects of saltwater on metal and sensitive electronics, the casing of key NEPTUNE Canada components is made of corrosion-resistant titanium.
How do you connect a node to the power supply when it’s submerged in saltwater? You design a “wetmate” connector, which triggers vegetable oil to displace the saltwater so that the electrical connection can safely be made.
The nodes and junction boxes would quickly overheat if they operated on land. On the seafloor, the 2 degrees C water temperature helps keep them cool.
Nodes can be lifted in and out of their TRFs for maintenance and replacement by the ROPOS submersible.
Each node communicates through the fibre-optic network using its own dedicated wavelength (colour) of light.
Each node is designed to handle the 10,000 volts of direct current that is constantly flowing along the 800-km cable loop. The average household socket handles 120 volts.
The high bandwidth Internet connection between the Port Alberni shore station and UVic, contracted from Shaw Business Solutions, carries up to 10 billion bits per second—the equivalent of a simultaneous broadcast of 500 HDTV channels.
The data management and archive system used by NEPTUNE Canada also supports the VENUS (Victoria Experimental Network Under the Sea) ocean observatory, also based at UVic. It has two instrumented cable networks already in operation—one in Saanich Inlet near Victoria, BC, and the other in the Strait of Georgia near Vancouver, BC. For more information on VENUS visit www.venus.uvic.ca.
Ocean Networks Canada (ONC) is a not-for-profit society created in 2007 by the University of Victoria to develop and manage the VENUS and NEPTUNE Canada ocean observatories, to position Canada as an international leader in the science and technology of ocean observing systems, and to maximize associated economic and societal benefits through commercialization and outreach. For more information, visit www.oceannetworks.ca.
For more information on NEPTUNE Canada visit www.neptunecanada.ca