This image may look like a Christmas tree decoration, but it was actually taken using a microscope. It shows eight individual diatoms arranged in a star shape.
Diatoms are a large group of unicellular algae. They are found all around the world from the poles to the tropics and are found in both fresh and salt water.
They are very important as they form the basis of the aquatic food chain, so many organisms ultimately rely on them to survive. They are highly sensitive indicators of environmental change and used extensively in routine environmental monitoring of watercourses.
This image is taken from a slide from the botany collection at World Museum.
Accession number LIV.2001.71.845
Frustulia rhomboides (Ehrenberg) De Toni, from Monmouth USA