At KTH, Long-Term Underwater Sensing platforms (LoTUS buoys) have recently been developed in collaboration between natural scientists and engineers as the solution to a specific need: to measure water temperature accurately for extended periods of time (up to 10 years) at depths of down to 2000 meters, for deployment e.g. in the harsh environment of Polar Oceans. Production costs are kept relatively low, and robustness kept high. It is planned, in other projects, to extend the capabilities of the LoTUS buoys so that they can collect more in-situ – e.g. conductivity, depth, and current velocity and direction. The development of LoTUS to include new sensors is part of a proposal submitted recently to the Swedish Research Council.

In this proposed project, we aim to pilot-study the use of the existing version of LoTUS buoys in a ”vertical array configuration”, and collect data at discrete heights through the watercolumn. Vertical profiling is key to understanding the dynamics of watermasses.

The researchers involved in this study suggest manufacturing and testing handling and performance of a prototype of a vertical array of LoTUS buoys, at different locations in the Baltic Sea. Because the proposed project is technology focused, it can easily be conducted jointly with other R/V Electra science missions.

In order to keep this as cost-efficcient as possible, R/V Electra’s high-resolution multibeam echosounder will be used together with a midwater column mapper (”fishfinder”) to retrieve the one vertical LoTUS array after short test periods. The proposed tests are expected to be of key importance prior to deployment of vertical LoTUS arrays in the framework of science projects devoted to improving understanding of a number of submarine Earth Science and Environmental processes, by providing much needed long-term in situ dataseries.

Researchers and departments:

Nina Kirchner, Department of Physical Geography
Jakob Kuttenkeuler, KTH Centre for Naval Architecture