First high-res look at microbial ballistics: Harpoons, spears, Gatling guns

Enlarge / A close-up of Polykrilos kofoidii. (credit: Urban Tillmann.)

When you think of plankton, you might think of docile, intricately shaped microbes gently swaying in ocean currents while generously providing food for all manner of sea creatures. Serene. Charming. In reality, they’re little savages who constantly take each other out with sophisticated ballistic weapons.

In a new study published in Science Advances, researchers nabbed the first high-resolution images of those impressive arsenals. The militarized microbes are packing spears, harpoons, and miniaturized versions of a Gatling gun, complete with up to 15 barrels. The images and analysis provide the most detailed assessment yet of plankton’s elaborate weaponry. Those ballistics were hypothesized by some to be the evolutionary root of similar ballistics seen in other, distantly related sea creatures, such as jellyfish. But with the new data, the authors, led by researchers at the University of British Columbia, suggest that the microbes’ arms evolved separately and are uniquely complex.

To get the money shots, the researchers used focused ion beam scanning electron microscopy and assembled the images to create 3D reconstructions. They started with Polykrikos kofoidii, a single-celled eukaryote in a group called dinoflagellates. They’re known to use a harpoon-like weapon to hunt down other plankton critters, including ones that cause toxic algae blooms.