In pictures: Scots-Norwegian polar winter study

Image copyright Geir Johnsen

Image caption A naked sea angel, one of the creatures encountered on a recently-completed research trip

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.

Image copyright Michael O Snyder

Image caption Scientists from Norway and Scotland collaborated on the research trip

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.

Image copyright Geir Johnsen

Image caption A stinging jellyfish on the move on a polar winter night

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.

Image copyright Geir Johnsen

Image caption Phosphorescence, a luminous glow created by millions of microscopic marine organisms

All images are copyrighted.