Autonomous deep-sea robot at work
Deep on the Arctic seabed, an autonomous deep-sea robot has been hard at work, having recently started its one-year mission to measure oxygen levels at the seabed on a weekly basis. Designed by a team of scientists and engineers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, the crawler has been christened Tramper.
Its functions – sleeping, moving, taking photographs and measurements – appear pretty easy. However, the team is a little more cautious, since all these take place underwater at temperatures near freezing point. Hence, Tramper kicked off its mission with a little test run, in which it travelled 123 metres and completed seven measuring cycles over two days at a 1,500-metre depth – this test Tramper had passed with flying colours.
This paved the way for the crawler to be deployed on its maiden mission on 11 July 2016. A video-guided launcher system conveyed the device safely to the seabed at a depth of 2,500 metres. To perform its mission, Tramper moves 15 metres to an undisturbed location, then an image recognition will survey the area. If any stone or object is recognised, it will move two metres away from its current spot before taking another photograph. Then, the measurements at the site begin, in which sensors are placed in the sediment at increments of 0.1 millimetres to measure the oxygen distribution in the seabed.
After taking the measurements, Tramper goes into a sleep mode for a week to conserve energy. “Ultimately, it should perform more than 52 such measurements cycles – and at a temperature of minus 1.8 degrees Celsius, which places a strong demand on the batteries,” said Dr Frank Wenzhöfer, a scientist at the Helmholtz Max Planck Joint Research Group for Deep-Sea Ecology and Technology.
At the end of the project, the scientists will use the measurements to investigate the activity of microorganisms at the seabed. Microorganisms like bacteria are mainly responsible for the degradation of organic matter in the seabed, while consuming the oxygen within it. The amount of dead algae at the seabed determines the level of bacterial activity and hence the oxygen consumption.
The scientists will use the measurements provided by Tramper to identify the natural variation over the course of the year. “Statements can also be made about how the ecosystem of the Arctic seabed responds to environmental changes. Such data about the Arctic are still incomplete,” said Dr Wenzhöfer.
The research team is already looking forward to their next expedition in 2017, in which they will return to the Arctic on board the RV Polarstern and retrieve the Tramper – hopefully “safe and sound, and full of valuable data!”
More information: www.awi.de
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