A beautiful oak leaf portrait won the 2021 Nikon Small World photography contest

Annual competition features snapshots of the world hidden from the naked eye

A closeup of a southern live oak leaf, shown at 60 times magnification, with the leaf's trichomes in white, vessels in cyan and stomata in purple

In this closeup view of a southern live oak leaf, shown at 60 times magnification, protective structures called trichomes are colored white, vessels are in cyan and stomata in purple.

Jason Kirk/Baylor College of Medicine, Nikon Small World

A closeup view of even the most common objects can make the mundane look spectacular.

A glimpse of the underside of a southern live oak tree leaf, which won first place in the 2021 Nikon Small World photomicroscopy competition, is just one example. Jason Kirk, director of Baylor College of Medicine’s Optical Imaging and Vital Microscopy Core in Houston and a self-described microscope enthusiast, snapped the prizewinning photo with a microscope that he finished building in the early days of the coronavirus pandemic. He tested his homemade device with a variety of objects from his yard, including tree leaves.

“A lot of times, you stick weird stuff under the microscope and see what it looks like,” Kirk says. “That’s what happened with this.”   

His daughter remarked that the leaf’s trichomes — structures that help protect plants and other organisms from extreme weather and insects — looked like sea anemones. That comment inspired Kirk to craft a photo that made the leaf’s underside look like an underwater landscape.

The picture is a composite of around 200 images stacked together. The leaf’s trichomes are colored white and stick out of cyan-colored vessels, which carry water. Surrounding stomata, colored purple, regulate the flow of gases such as carbon dioxide.

The oak leaf was one of 100 stunning images recognized in this year’s competition, the results of which were announced September 13. Here are a few of our favorites.

A sky full of neurons

close-up of 300,000 nerve cells stained to fluoresce green or orange , with nuclei in blue
Around 300,000 nerve cells stained to fluoresce green or orange illuminate this snapshot, shown at 20 times magnification. The cells’ nuclei are blue.Esmeralda Paric and Holly Stefen/Macquarie University, Nikon Small World

It took a month of work for Esmeralda Paric and Holly Stefen, both of Macquarie University in Sydney, to capture this striking scene. Though at first glance it might look like a peek at galaxies, those glowing “stars” are mouse brain cells — part of an experiment that could help researchers understand the mechanisms behind neurogenerative diseases such as dementia.

The image, which earned second place in the competition, shows around 300,000 nerve cells, or neurons, separated by inky black fluid. The researchers coaxed some of the cells to extend spindly structures called axons, which allow neurons to send electrical signals, across the fluid.

“I named [the image] ‘The Jedi and the Sith’ … because when I look at it, I am compelled to reflect on [the] balance and connections that exist between otherwise seemingly isolated or opposing sides,” Paric says.

Her friends, however, had another name for the image. They “lovingly dubbed it ‘The Neuroverse,’” she says.

A menacing louse

a microscopic close-up of a hog louse's claw
This claw, shown at five times magnification, belongs to a hog louse (Haematopinus suis).Frank Reiser/Nassau Community College, Nikon Small World

Is it a scorpion’s tail? Or perhaps a crab’s claw?

No, this menacing, microscopic snapshot shows a side view of the rear leg and claw of a hog louse (Haematopinus suis). The hog louse lives primarily on swine, where the insect feeds on blood, and is one of the largest sucking lice. Severely infested pigs can go bald.

Retired biology professor Frank Reiser of Nassau Community College in Garden City, N.Y., captured this picture, which won third place, using dark-field microscopy to make the inner workings of the transparent louse clearly visible. The tubes running along the louse are respiratory tubes, called tracheae, carrying oxygen to tissues.  

An embryonic rat’s whirl of nerves

cluster of nerve cells from a rat embryo. The major structural component of the cells, the outside of the whirl, is green. The supporting structure is red. The nuclei are blue.
This photo shows a cluster of nerve cells called a dorsal root ganglion, shown at 10 times magnification, from a 16-day-old rat embryo. The major structural component of the cells, the outside of the whirl, is colored green, and the supporting structure is red. Cells’ nuclei are blue.Paula Díaz Cespedes/MinusPain, Pontificia Universidad Católica de Chile, Nikon Small World

As part of a doctoral thesis project, Paula Díaz Cespedes of Pontificia Universidad Católica de Chile in Santiago, who studies injury-related nerve pain, snapped this stunning picture of nerve cells from a 16-day-old rat embryo. The photograph earned fourth place in the competition.

The colorful whirl is a dorsal root ganglion, a cluster of sensory nerve cells, including ones that detect pain. These clusters are found close to the spinal cord in many animals. The major structural component of the cells is colored green, with supporting cells that keep the neurons alive colored red. The nuclei of cells are blue.

Studying how the dorsal root ganglion changes after a painful injury can help researchers better understand chronic pain, Díaz Cespedes says.

A kaleidoscope of dinosaur bone

a magnified slice of dinosaur bone in vibrant colors
This closeup view of a thin slice of mineralized dinosaur bone, shown at five times magnification, showcases a dizzying display of color, thanks to how polarized light interacts with the mineral that fills the bone’s pores.Bernardo Cesare/University of Padua, Nikon Small World

This work of art isn’t a stained-glass window. It’s a zoomed-in view of a tiny piece of dinosaur bone.

Geologist Bernardo Cesare of the University of Padua in Italy stitched together 25 images to create the picture. The black blobs are fossil remnants of the bone tissue that hosted a single bone cell. The different colors come from polarized light passing through mineral-filled pores within the sliver of bone. As the light moves through the mineral — called chalcedony, a type of quartz — the thickness and orientation of the crystals in relation to the light emit a rainbow of colors.

The small bone fragment, which was unearthed in Utah, inspired many photos such as this one, Cesare says.     

A sea of villi

Villi from mouse intestine lining shown at 63 times magnification in blue and green
Millions of tiny projections called villi coat the lining of our intestines to help absorb nutrients and keep us healthy. This image depicts mouse villi, shown at 63 times magnification, that were manipulated to fluoresce blue and green.Caleb Dawson/Walter and Eliza Hall Institute of Medical Research, Nikon Small World

Caleb Dawson of the Walter and Eliza Hall Institute of Medical Researcher in Parkville, Australia wants to know how the intestine handles the myriad microbes living there. To do that, he plans to image immune cells in the gut. Those immune cells live among and inside tentacle-like structures called villi, shown in this striking picture of a mouse’s intestine.

Showing the villi in their three-dimensional glory was difficult, Dawson says. The task required compiling thousands of images taken in different positions while scanning intestinal tissue. Dawson added antibodies and dyes to the tissue to make parts of the villi fluoresce blue or green under certain types of light.

Erin I. Garcia de Jesus is a staff writer at Science News. She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.