Taking a 4,000-Meter-Deep Profile of Antarctic Waters
In addition to understanding potential pathways for “warmer” circumpolar deep water to reach the ice shelf, we are also measuring what the structure and properties of the water column are and determining if there is already warmer water on or near the continental shelf that could already interact with the glaciers of East Antarctica today.
To measure water properties, we are using an instrument that can be lowered through the water column that measures conductivity, from which we calculate the salinity of the water, temperature, pressure (i.e. water depth), oxygen, and fluorescence, which is an indicator for phytoplankton or algae in the water. This system is called a CTD for short.
This system can also take water samples from different depths that can be used for further analysis or for calibration and verification of the sensors. When we lower this system in deep water, e.g. 4000 meters, (about 2.5 miles), the measurements take over three hours.
We have measured the water properties at 42 different locations during our expedition and will analyze the results carefully when we are back.
Follow @FrankatSea for additional updates and images from the Southern Ocean.