Spain’s first seafloor laboratory, the Expandable Seafloor Observatory (OBSEA), located three miles off the coast of Vilanova i la Geltrú at a depth of 20 meters, has begun real-time transmissions to the laboratories of the Universitat Politècnica de Catalunya (UPC) and the Spanish National Research Council (CSIC). The data it collects will make it possible to study the Mediterranean seafloor via the Internet. This pioneering underwater platform, installed in March with the help of the CSIC’s oceanographic research ship Sarmiento de Gamboa, has successfully completed its two-month test period.

The platform will make it possible to assess water quality by studying slight variations in temperature and/or salinity, determine the level of noise pollution by studying acoustic signals from natural or manmade sources, and evaluate the degree of pollution caused by waste and sea transport. The Observatory will be able to record underwater processes uninterruptedly, thanks to a 4.5-km optical-fiber power supply cable that eliminates the need for limited-life energy sources such as batteries. The project forms part of the European Seafloor Observatory Network (ESONET).

This scientific facility is made up of two cylinders: one housing electronic components and another housing the system’s power supply cables. The first cylinder also houses connections to three sensors: an IP camera that records images of the seafloor, which can be moved and focused from the land station and accessed via the Internet; a hydrophone, which records underwater acoustic variations; and a CTD (conductivity, temperature and depth) device, which measures salinity, temperature and depth.

A series of optical-fiber power supply cables connects the OBSEA to a management unit located at the Vilanova i la Geltrú Technology Center (CTVG). The land-based cables were installed in 2008 and cover a distance of 1.5 km: from the power supply unit at the School of Engineering of Vilanova i la Geltrú, along the course of various stream beds, to the lighthouse bridge. An underground anchorage chamber installed at the lighthouse bridge connects the land-based cables to the underwater cables, which start at the lighthouse beach and run along the seafloor for three miles.

These optical-fiber cables provide energy and transmit information (data and images recorded by the Observatory’s equipment) without interruption. The entire system (optical-fiber cables, power supply and electronics) is duplicated so that malfunctions can be fixed without interrupting the OBSEA’s work. The Observatory also has a system of controls and alarms designed to prevent technical problems in the operation of the infrastructure.

In the future, the laboratory will be moved to a greater depth, more nodes will be added, and the platform will be made accessible to the wider scientific and industrial community. As a result, the laboratory will be able to carry out longer-term observations and serve as a test site for the development of new underwater sensors. Because this high-tech unit will be able to help other groups around the world with their research, it could help Vilanova i la Geltrú to become an important oceanographic research hub in the Mediterranean region.

Antoni Mànuel, a researcher from the UPC, and Juanjo Dañobeitia, the director of the CSIC’s Marine Technology Unit, lead the two research groups that have worked on this project. Mànuel and Dañobeitia consider that the OBSEA will open up a wide range of opportunities for both marine research and Spanish industry.

Future research

The OBSEA is capable of various kinds of studies, depending on the types of sensors enabled and the location of the platform on the seafloor; if a different kind of study needs to be carried out, the appropriate sensor can be installed. As a result of this set-up, the facility offers a wide range of possibilities. It can be used to identify geological risks; detect earthquakes and tsunamis; monitor active seismic faults, volcanic eruptions and underwater landslides; and study ocean currents, sea-level variations and meteorological phenomena.

The Observatory will provide relevant data for the study of climate change; the physical, chemical and biological interactions that affect marine organisms and ecosystems; the environmental impact of sea transport and port traffic; and the safety of cargo shipping.

Source: redOrbit