Research Plans for a Mid-Depth Cabled Seafloor Observatory in Western Canada
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Special Issue—Ocean Observations Research Plans for a Mid-depth Cabled Seafloor Observatory in Western Canada Verena Tunnicliffe, Richard Dewey and Deborah Smith 5912 LeMay Road, Rockville, MD 20851-2326, USA. Road, 5912 LeMay The Oceanography machine, reposting, or other means without prior authorization of portion photocopy of this articleof any by Copyrigh Society. The Oceanography journal 16, Number 4, a quarterly of Volume in Oceanography, This article has been published VENUS Project University of Victoria • Victoria BC Canada As the first cabled seafloor observatory that Primary review, conducted by CFI, was based on the involves a geographically distributed network struc- quality of science proposed and the ultimate researcher ture, the Victoria Experimental Network Under the Sea group. It is, however, only the infrastructure that is fund- (VENUS) will oversee the deployment of three pow- ed and an initial operating stage. A major challenge for ered fiber-optic cable lines in British Columbia’s (B.C.) VENUS is to find subsequent operational funds and to southern waters. The funded infrastructure will offer encourage the development of user groups. Thus, to two-way high-speed communication access and inter- write the proposal we involved the users. Over 30 scien- action in 24-hour real time from the ocean floor and tists defined the mandate for VENUS and a subset craft- water column to a land based location. With an expect- ed the proposal that requested funding for cable and ed life of at least 20 years, each cable line will have a seafloor node installations, shore stations and data man- unique set of instrument suite combinations that will agement development plus some instruments to initiate reflect the environmental processes being studied by research activity. The primary objective of VENUS is to participating scientists and researchers. Internet access support research into seafloor and water column to data will be available for all: collaborators, scientists, processes at three locations. Data and user policies are in students and the public. This new approach to sharing development but our expectation is: i) to provide a 24- data will undoubtedly change the pace of understand- hour datastream to users; ii) to promote array access for ing about the oceans for both the scientific community additional instrumentation to funded researchers from and the general public. any country; and iii) to allow web access to near real- time data from community instruments and as many The Vision for VENUS investigator instruments as possible. The concept for VENUS was derived from discus- sions of Canadian involvement with the NEPTUNE Development of the Installation project. We link closely with NEPTUNE developments VENUS is a cabled ocean exploration project. but VENUS has separate goals, clientele and funding. VENUS cables will provide two-way full-time access Our incentive is twofold: i) the need for better access to and interaction to ocean and subsea environmental the dynamic ocean between Vancouver Island and the conditions for twenty years. Three separate cable lines Society is strictly prohibited. Send all correspondence or Society is strictly to: [email protected], mainland and ii) the desire to entrain Canadian scien- will be laid in Saanich Inlet, Strait of Georgia, and Juan t 2003 by The Oceanography Society. All rights reserved.Reproduction Society. The Oceanography t 2003 by tists into the cabled observatory concept. Impetus for a de Fuca Strait (Figure 1) with landfalls in British large regional cabled observatory off North America Columbia. With general sites selected by science is growing but it will take time to develop new obser- groups to address issues of greatest interest; actual vational and data processing techniques. VENUS pro- routing needs are under examination as science proj- vides a learning base. ects are reassessed and site surveys conducted. The first The Canadian Foundation for Innovation (CFI), VENUS cable will be laid in Saanich Inlet in early 2004. provided initial funding to 40%. This government cor- Strait of Georgia and Juan de Fuca Strait cables will be poration invests in Canadian research infrastructure. laid with one cable ship deployment with nodes Funding decisions reflect capacity for innovation, installed at depths of 300 and 170 m respectively. These training, and research collaborations. 40% of the proj- second and third cables are planned for 2005. This ect is funded from the British Columbia Knowledge aggressive schedule will see about 30 km cable laid Development Fund, which examines potential for eco- across the Strait of Georgia from B.C.’s largest delta nomic enhancement from research infrastructure, and towards Vancouver Island. The funded Juan de Fuca 20% came as in-kind contributions from industry and Strait line will extend from Pedder Bay, B.C. southward government partners. VENUS has a Can$10.2 million to the border. Ongoing discussions with U.S. partners budget over four years that is overseen by the are assessing extension of the line to complete the University of Victoria. crossing into Washington State—about another 10 km. Oceanography • Vol. 16 • No. 4/2003 53 Figure 1. VENUS will consist of three cables deployed in the waters between Vancouver Island and the mainland. The Saanich Inlet cable (a) is sched- uled for a 2004 deployment. The remaining two cable lines (b) (c) will likely be deployed in late 2005. However, funding for the Juan de Fuca Strait cable (c) that crosses into U.S. waters is not yet secure. Figure 2. A cross-section of Strait of Georgia reveals the challenges in cable lay: first, through an active deltafront and secondly, over exposed bedrock ridges. The dynamic conditions that cause these features also attract researchers. A vertical profiler is planned for mid channel deployment as is an extension cable to a seismometer at an active fault 4 km to the north. Oceanography • Vol. 16 • No. 4/2003 54 A standard Alcatel telecommunications cable with networking with resource users such as trawlers to eight optical fibers and a single power conductor has gain support for protection of the cables and instru- been purchased (Figure 2). Armoring varies dependent ments. Similarly, local public awareness and support of on bottom lay conditions. Up to ten kilowatts of shore the cable locations/landings is considered important. power will be stepped down on the seafloor to deliver In both cases, we argue that the long-term benefits of 48 volts DC to instruments (Howe et al., 2002). Multiple the results will benefit both the resource and society. ports will be available for wet mateable connections to We intend to promote support in the long term by instruments that may extend several kilometers from seeking funding for public outreach programmes. the conversion node. Communication to seafloor instrumentation will be via stand Ethernet protocols Oceanographic Features of the Region with an IP address for each instrument using an optical Amajor factor in siting VENUS in Canada was the transport layer. Saanich Inlet array will be the test bed rich suite of ocean processes and ecosystems around for the telecommunications and power systems allow- Vancouver Island. Deglaciation created the numerous ing for further development of the data management sounds and inlets along the British Columbia coast and control systems. Eventually, three shore stations including the deep, broad channel of Juan de Fuca will link with land lines (either directly or microwaved) Strait that joins the inland basins of Puget Sound and to connect to the VENUS Data Management and Strait of Georgia with the Pacific Ocean. A marine tem- Archive System. This developmental system will begin perate climate provides ample rain and snowmelt to with standardized file transfer protocols but build to a coastal mountain rivers that drain into these basins formatting, display and interrogation design compati- with seasonal variability. Driven by this buoyant dis- ble with other ocean observing systems. charge, a large estuarine circulation is established Each cable array will have a different combination through the Gulf and San Juan Islands before emptying of instrument packages reflecting the studies envi- through Juan de Fuca Strait onto the continental shelf sioned for that location: fish tag receiver, shoebox node, west of Vancouver Island. This exchange is moderated sediment dynamics package, major bottom package, by vigorous tidal currents and mixing, as the Strait of vertical profiler and piezometer and/or seismometer. Georgia and Puget Sound respond to the mainly semi- The Saanich Inlet cable will have one scientific node diurnal tidal forcing at the western entrance to Juan de that will support multiple scientific packages; the Strait Fuca Strait (Thomson, 1981). of Georgia and Juan de Fuca Strait will each have two Wind and tidal mixing enhances the estuarine nodes (or three if extended). While it will be possible to exchange, which grows from 105 m3 s-1 at the river lift the node to the surface for repair, that operation will mouths, to nearly 106 m3 s-1 in Juan de Fuca Strait. A not be routine for connecting instruments. Either a sub- deep, saline inflow balances this flux and carries abun- mersible will plug a new instrument in on the seafloor, dant nutrients, enhanced during the summer months or a capped extension cord will be raised (by grappling by large-scale coastal upwelling over the continental or release) to the surface for ship-based deployment. shelf. High productivity throughout the region sup- VENUS installation and maintenance will rely heavily ports salmon and herring fisheries, as well as eco- on ROV access to the array. One such vehicle is operat- tourists who seek the resident marine mammals. ed locally by the Canadian Scientific Submersible Circulation on the broad continental shelf west of Facility: ROPOS is a 40 hp ROV with two manipulators. Vancouver Island varies seasonally, with northward, Major steps of the VENUS cable installation downwelling conditions during the winter, and south- sequence include: define instrument locations in con- ward, upwelling conditions during the summer.