Microscopic Marvels

Thousands of tiny species discovered in seawater, sand, and soil.

This is not a tiny, deformed pineapple. It’s a kind of amoeba (Hyalosphenia papilio), a type of single-celled protist found on the BC Central Coast. Photo by Thierry Heger

Humans like to think big. But if we look closer, a whole miniature world full of infinitesimal creatures is revealed. Tiny, single-celled organisms of all shapes and sizes are hiding in every habitat we explore from seawater to sand to soil. And genetic technologies are giving Hakai researchers a new window into this microscopic world where they are discovering a plethora of new species, sometimes in unexpected places.

“It’s very exciting. You can find something which has never been described before,” says Thierry Heger, a Hakai post-doctoral scholar at the University of British Columbia.

Heger’s research focuses on protists, a group of single-celled creatures that includes amoebas and diatoms. Protists may only have one cell, but their internal structure is more complex than bacteria.

How many protist species live in one area?

It was not previously possible to study the myriad species of protists across a whole area like a watershed. There were just too many species for taxonomists to describe. However, now scientists like Heger don’t need the whole creature to describe them. He just needs a piece of their DNA.

“We didn’t [used to] have the tools to study the enormous diversity of protists. Now [with genetic technologies] we have the possibility to do that,” says Heger.

Heger collects samples from up and down the Kwakshua watershed on the Central Coast of British Columbia from the bog to the forest to the ocean. Genetic material from these samples is analyzed using a technique called “high-throughput DNA sequencing.” By using their DNA, Heger can identify what protist species live in each habitat in the watershed—a comprehensive study that has never been done before in the region.

Thierry Heger, a Hakai post-doctoral scholar at the University of British Columbia, shows a patch of soil that contains countless microscopic protists representing thousands of species. Many of these species are new to science. Photo by Thierry Heger

A spiky amoeba (Placocista spinosa) found in moss. Photo by Thierry Heger

Remarkable diversity

Among Heger’s findings were some species surprises. One protist group, the opisthokonts (pronounced o-piss-toe-kahnts), were thought to be exclusively found in aquatic ecosystems. Heger was amazed to discover an abundance of species in this group outside of water living in the soil. The “exclusively aquatic opisthokonts” is unfortunately no longer a valid tongue-twister.

Protists’ role in the ecosystem

Now, the next step is piecing together how this microscopic realm interacts with the world visible to the human eye. Protists and other microscopic creatures often carry out some of an ecosystem’s biggest tasks. Heger has found protists doing important work in every ecosystem he’s sampled, from photosynthesizing and producing nutrients to preying on bacteria and other single-celled creatures.

By looking closer at these single-celled marvels, Heger and his colleagues are discovering new species, and finding out how they are contributing to every section of the watershed. To fully understand the ecosystem, we’ll have to think small.

Acknowledgments

Thierrys research would not be possible without the collaboration of several members of the Keeling lab, as well as financial support from the Tula Foundation and the Swiss National Science Foundation. Thierrys research is part of Hakai InstituteKwakshua Watersheds Program, a long-term study investigating the flux of terrestrial materials from land to sea.