Mapping the Seafloor

One of the goals of this expedition is to investigate if water from the Southern Ocean with temperatures above the melting point of glaciers could reach the glaciers in East Antarctica, and if there are any obstacles on the seafloor of the shelf that impact the ability of such water to reach the glaciers and ice streams.

By
Frank Nitsche
April 20, 2015
In addition to depth, we can identify many features in the high-resolution multibeam data that we produce. Most of the seafloor near the shelf break (where the water is between 300 and 500 meters deep) is covered with these irregular furrows that are created when large icebergs are grounded here.
In addition to depth, we can identify many features in the high-resolution multibeam data that we produce. Most of the seafloor near the shelf break (where the water is between 300 and 500 meters deep) is covered with these irregular furrows that are created when large icebergs are grounded here.

One of the goals of this expedition is to investigate if water from the Southern Ocean with temperatures above the melting point of glaciers could reach the glaciers in East Antarctica, and if there are any obstacles on the seafloor of the shelf that impact the ability of such water to reach the glaciers and ice streams.

The continental shelf in our study areas along the East Antarctic margin has been mapped in the past, but the existing data are very sparse and have many gaps. However, it is important to know the actual water depth of the continental shelf if we want to understand if water from the Southern Ocean with temperatures above the melting point could reach any glaciers and ice streams in this part of Antarctica.

We use a multibeam echosounder system installed on the Nathaniel Palmer to map the depth of a wide swath of the seafloor along our ship track. Access to the continental shelf is often limited by dense ice cover, but using the multibeam, we have managed to determine detailed depths in several areas. We will later analyze the depth data together with measurements of water column properties that will tell us exactly how deep the “warmer” Southern Ocean water is.

Follow @FrankatSea for additional updates and images from the Southern Ocean.