In pictures: Scots-Norwegian polar winter study
Scientists have returned from a research trip to the Arctic with images of some of the sea life active during the region's dark polar winters.
UiT The Arctic University of Norway and Oban's Scottish Association for Marine Science - which is part of the University of the Highlands and Islands - collaborated on the study of the unusual and colourful creatures.
They include luminescent fish and plankton.
The animals use the long dark polar winters to lay eggs, spawn and grow.
Self-propelled and remote-controlled underwater robots and divers equipped with cameras were used to capture many of the images.
Film-maker Michael O Snyder and Geir Johnsen from the Norwegian University of Science and Technology were among those who took the photographs.
The imagery features in a new documentary about the Arctic's polar winters, Into the Dark.
All images are copyrighted.