Obtaining long term data series in polar regions is becoming increasingly important to better understand and model ongoing environmental changes. However, the duration of current projects rarely exceed 5 years. Engineers at the KTH Royal Institute of Technology in Stockholm and oceanographers at the University of Gothenburg recently formed a collaboration to develop an autonomous sensing platform designed for long-term underwater operation.

LoTUS bottom lander mounted on the CTD rosette for depth rating testing. Phot: Jari Krützfeldt

LoTUS bottom lander mounted on the CTD rosette for depth rating testing. Phot: Jari Krützfeldt

The LoTUS, Long Term Underwater Sensing, bottom lander system is a new and innovative temperature probe, designed for operations in remote regions for up to 10 years in water depths up to 2,000 m, including a secondary drift function, that transmits the buoys GPS coordinates at pre-set intervals. Currently in a prototype phase, the Petermann 2015 project aimed at conducting tests under realistic conditions. A set of ten LoTUS buoys were deployed at strategic positions in the Petermann area to track warm Atlantic water entering the fjord, water which is suspected to cause basal melting of the Petermann glacier.

Just as scheduled, two bottom landers have surfaced in the Petermann area and have transmitted valuable temperature data. The remaining bottom landers will surface in the coming months and hopefully contribute to a better understanding of the Petermann glacier system.

The CTD and Bottom Lander team. Photo:  Jari Krützfeldt

The CTD and Bottom Lander team. Photo: Jari Krützfeldt

LoTUS bottom lander mounted on the CTD rosette for depth rating testing. Photo: Jari Krützfeldt

LoTUS bottom lander mounted on the CTD rosette for depth rating testing. Photo: Jari Krützfeldt

LoTUS bottom landers ready to be deployed. Photo: Jari Krützfeldt

LoTUS bottom landers ready to be deployed. Photo: Jari Krützfeldt

LoTUS bottom lander deployment from IB Oden. Photo: Jari Krützfeldt

LoTUS bottom lander deployment from icebreaker Oden. Photo: Robert Holden

Carefully lowering a LoTUS bottom lander for deployment. Photo: Jari Krützfeldt

Carefully lowering a LoTUS bottom lander for deployment. Photo: Robert Holden