‘twas a dark and stormy night. The OOI Argentine Basin Array swayed gently in the water column recording observations and streaming the data back to shore. Then from the briny depths came…THE KRAKEN!!…and dragged the moorings one at a time down to its lair.
In early June 2016 the two Flanking Subsurface Moorings on the OOI Global Argentine Basin Array experienced extreme pressure changes wherein the pressure recorded by the CTDs affixed to the mooring riser at a depth of 30m slowly began to increase until registering maximum pressures around 500 dbar. The other CTDs deployed at various depths on the moorings also recorded similar increases in pressure, though only the data from the 30m CTDs are shown here. At the same time, Acoustic Doppler Current Profile (ADCP) data from the moorings show a shift from an eastward current to a westward one, in addition to a substantial increase in pressure.
Looking at the satellite data, it is clear that the cause of this extreme pressure change and dragging of these two moorings downward was not the Kraken, but rather downwelling eddy activity in the area as a warm core ring can be seen breaking off from the Brazil current and moving west through the array. For more information on warm core rings, check out this OOI Pioneer Array nugget.
It is easy to see how ocean folklore developed hundreds and thousands of years ago from Charybdis in ancient Greece to Jules Verne’s giant squid in “20,000 Leagues Under the Sea.” These tales help to explain the unexplained and humans have relied on the ocean for food and transport much longer than we have had a detailed understanding of its physical properties. In many ways, the ocean still continues to be the next frontier of discovery.