Ocean processes don’t start and stop with the arrival and departure of an oceanographic research vessel. Currents are ceaselessly moving, plankton constantly bloom, the seafloor is continually being built—all of it happening over months, years, and decades.
In order to collect long-term views of these and other processes at work in the ocean, scientists and engineers have devised ways to leave instruments out in the environment. Moorings—secured by wires, buoys, weights, and floats—are platforms which allow us to observe how the ocean and seafloor change.Most of us are familiar with common moorings, which use anchors and cables or ropes to secure boats, channel markers, and other floating objects in fixed places in our waterways. Fixed oceanographic moorings work on the same principles, but the lines can be thousands of meters long and may or may not poke above the surface of the water. Scientific instruments can be attached to the mooring line, mounted on a surface buoy, or made to climb up and down the underwater line.
Coastal and Global Scale Nodes Moorings
CGSN moorings are innovative and more capable mechanically and electronically than previous oceanographic designs.
The moorings use a combination of nylon-jacketed steel wire rope, various types of synthetic line, electromechanical (EM) cable with copper conductors and electro-optical mechanical (EOM) cable with copper conductors and optical fibers. Steel wire rope can be used not only for strength and resistance to fish-bite but also for inductive telemetry of data from moored instrument packages.
With inductive telemetry, a controller on the mooring (usually at the buoy) can receive data and send commands to instruments on the mooring line below. The wire rope also provides the pathway for wire-following profilers to ascend and descend by traction motors or buoyancy control.