CTD Castaway

Sontek Castaway is the Arctic Eider Society's latest industry sponsor, and we're very pleased with how this innovative salinity, temperature and depth profiling equipment integrates into our community-driven research programs.

CTD stands for Conductivity (a proxy for salinity or salt levels of the water), Temperature and Depth (measured using a pressure sensor). This oceanographic equipment provides details of the layers of fresh and salt water in the marine environment and their dynamics that are critical to understanding sea ice ecosystems.

With integrated GPS units, and an ability for community-based researchers to review results on site, the equipment ensures high accuracy of results and usability in the field.

Results include graphs showing both salinity and temperature by depth at the site - a snapshot of the water column. The units for salinity are PSU, roughly equivalent to parts per thousand of salt. Normal winter sea water in Hudson Bay is around 30PSU. Over large parts of east-Hudson Bay, layers of freshwater from 23-26PSU can be seen from 15 m to more than 25m deep, layer on top of deeper salt water (which is closer to the typical 30PSU salinity.

The Temperature graph is important as fresh water and salt water layers also have different temperatures than can affect mixing as well as salinity. The freezing point of fresh water is also warmer than that of salt water, so it is important to keep track of both salinity and temperature when considering how oceanography affects sea ice formation. [Coming soon: a reference scale for Salinity and Temperature!]

More Photos and Video's about the CTD Castaway coming soon. For now, this video shows how Inuit hunters deploy our CTDs from RBR which operate in a similar way with similar results.