SCIENTISTS based near Oban will use custom-built robots, capable of operating at depths of seven miles, to explore the deepest parts of the ocean in a bid to discover how life is sustained there.

The research team led by Professor Ronnie N. Glud, who is based at the University of Southern Denmark, and the Scottish Association for Marine Science (SAMS) at Dunstaffnage will take the unique step of studying and sampling organisms in their own deep sea environment.

These extreme ocean regions, known as 'hadal zones', occur where one plate of the earth's geological crust is sliding underneath a neighbouring plate, forming deep trenches in the seafloor.

The Hades Project requires three purpose-built robots to operate at extreme depths.

Previous expeditions led by Professor Glud, most notably to the Mariana Trench in the western Pacific Ocean the deepest part of the ocean, revealed surprisingly high levels of biological activity.

Professor Glud said: "It is extremely difficult to investigate what actually happens in the extreme deep."

The three trenches to be visited by the researchers are in the Pacific Ocean: the Atacama Trench off Chile (max depth five miles), Japan Trench south and east of Japan (5.9 miles) and Kermadec Trench north of New Zealand (6.24 miles).

Dr Robert Turnewitsch, Principal Investigator in Marine Geochemistry at SAMS, part of the University of the Highlands and Islands, was on the team that explored the Mariana Trench and his expertise has been called upon again.

He said "I want to be surprised; I want to find something that challenges our views and perceptions of the deep sea and we now have a great opportunity to do that."

Meanwhile a team of scientists from St Andrews University has developed a new computer modelling tool for assessing the impact of noise from the likes of offshore wind farms on marine mammal populations such as porpoises and dolphins.

Shipping, oil and gas exploration, defence activities and port, harbour and renewable energy construction all create noise.

Offshore wind turbines are installed using a method called 'pile driving', a large hammer driving foundation posts into the seabed generating short pulsed sounds every few seconds. The potential risk of injury and/or disturbance to marine mammals has been identified as a key consideration during planning for offshore wind projects in UK waters, but many other noise sources are less stringently regulated.

Dr Stephanie King, Honorary Research Fellow in the School of Biology, said: "The effects of noise on animal populations are a current global concern for policy-makers. We have developed a novel framework that can be used to broadly forecast the consequences of man-made disturbance on animal populations, which in principal, can be applied to a range of marine and terrestrial species and different types of disturbance."