An image of a multicoloured turtle embryo has been awarded first prize in the Nikon Small World Photomicrography Competition.

The image was created by microscopy technician Teresa Zgoda and university graduate Teresa Kugler using fluorescence and stereo microscopy.

"Microscopy lets us zoom in on the smallest organisms and building blocks that comprise our world — giving us a profound appreciation for the small things in life that far too often go unnoticed," Ms Kugler said.

"It allows me to do science with a purpose."

The pair's image was described by Nikon judges as a "masterful" example of image-stitching, with Ms Zgoda and Ms Kugler stacking hundreds of photos to create the final product.

"We are inspired by the beautiful images we see through the microscope," Ms Zgoda said.

"It's humbling and deeply fulfilling to be able to share that science with other people."

Igor Siwanowicz came second for his image of three single-cell freshwater protozoans, using confocal microscopy to capture the tiny details.

Igor Siwanowicz gave a close, technicolour insight to three single-celled organisms. ( Supplied: Igor Siwanowicz, courtesy of Nikon Small World )

Third place went to Daniel Smith Paredes's photo of an alligator embryo at 20 days of development.

It was created with immunofluorescence, a laboratory technique that uses fluorescent dyes, illustrating the formation of the tiny reptile's nerves and bones.

The alligator image was created using florescent dye. ( Supplied: Daniel Smith Paredes and Bhart-Anjan S. Bhullar, courtesy of Nikon Small World )

The competition is in its 45th year, attracting thousands of entries from scientists and artists internationally.

The male mosquito's face makes quite an impact under 6.3 magnification. ( Supplied: Jan Rosenboom, courtesy of Nikon Small World )

"Our goal has always been to show the world how art and science intersect," Nikon Instruments communications manager Eric Flem said.

"As new imaging and microscopy techniques develop over the years, our winners showcase these technology advances more and more creatively."

Caleb Foster managed to capture this close-up of a snow flake before it melted. ( Supplied: Caleb Foster, courtesy of Nikon Small World )

Nikon Small World's judging panel picked out the top 20 winners, with the competition honouring dozens of other photographers in the Images of Distinction category.

This spider's close-up was created in Spain, using a combination of image stacking and reflected light techniques. ( Supplied: Javier Ruperez, courtesy of Nikon Small World )

The entire gallery of winners and distinctions can be viewed at the Nikon Small World website.