To paraphrase Forrest Gump: “Diatom samples are like a box of chocolates. You never know what you’re gonna get.”

An image arranged to look like a box of chocolates, with brown diatom shapes against a purple background.
Imagine a sample box of diatom-shaped “chocolates.” Image: Joe Holmes © Canadian Museum of Nature

Researchers in the Botany section at the Canadian Museum of Nature recently discovered five new Canadian diatom species. Four were from a stream in the VanDusen Botanical Garden (VDBG), a beautiful green space located in central Vancouver, British Columbia. The fifth was from Gibson Lake in Renfrew County, Ontario, just north of Algonquin Provincial Park.

Diatoms are microscopic, photosynthetic algae with special shells made of silica, known as frustules. Found in freshwater and marine environments, as well as soil, they’re used by biologists to study water quality and climate change.

Senior Research Assistant Paul Hamilton runs a diatom research program at the Museum. He assists students and scientists by sharing his expertise and providing access to equipment and collections.I work with Paul as a volunteer and so-called citizen scientist, helping him with fieldwork, processing, microscope photography and analysis.

Four images. The top left shows the author sitting at a microscope with computer screens and diatom books open on a desk. The top right image shows a scanning electron microscope and several large computer screens. The bottom right shows a molecular biology laboratory with different types of equipment and supplies on the counters and shelves. The bottom left image shows a library shelf filled with diatom-related books.
Clockwise from the top left: Joe Holmes with a Leica light microscope (LM) (1,600x magnification); FEI Apreo Scanning Electron Microscope (SEM) (350,000x magnification); lab for DNA sequencing; algae lab library. Image: Joe Holmes © Canadian Museum of Nature

In December 2016, I visited my daughter in Vancouver, collecting 17 samples from nearby rivers and lakes. Back in the lab, and after “looking inside” the samples, we observed four potentially new species from the VanDusen Botanical Garden. Paul took more light microscopy photos and scanning electron microscopy images. Several months later, the botanical garden sent a live sample for DNA extraction. After further analyses, Paul co-authored a paper describing the new species, which you can read here.

The new species all belonged to the genus Neidium and were named: 1) N. vandusenense, for the VanDusen Botanical Garden; 2) N. collare, from the Latin for “neck band”; 3) N. lavoieanum, honouring scientist Dr. Isabelle Lavoie; and 4) N. beatyi, honouring the Beaty Foundation, generous supporters of the Museum.

Three images arranged in a grid. The top left shows a wintery scene with trees and a frozen stream. A red arrow indicates where the sample was taken. The top right image shows three black and white electron micrographs of diatoms; they are oval-shaped with pointy ends and are oriented with the longer axis running vertically. The bottom image shows two black and white electron micrographs of diatoms; they resemble long surfboards, with the longer axis running horizontally.
VanDusen Botanical Garden, December 28, 2016. Sample from a frozen stream between Victoria Pond and Livingstone Lake (background): 1) N. vandusenense (97 µm x 20 µm); 2) N. collare (98 µm x 20 µm); 3) N. lavoienum (70 µm x 19 µm); 4) N. beatyi (180 µm x 25 µm); and large known species, 5) N. iridis (205 µm x 30 µm). Image: Joe Holmes & Paul Hamilton © Canadian Museum of Nature.

Finally, a fifth species was recently discovered from Gibson Lake in northwestern Renfrew County, Ontario by Andréanne Bouchard, a graduate student at the University of Ottawa. After extensive verification, she co-authored a paper with Paul, describing the new species as Frustulia gibsonea.

Two images side-by-side. The left image is of a lake in summer, with blue water and green grass. A red arrow indicates where a sample was taken. The right image shows three electron micrographs of diatoms; they are an angular oval shape, with the longer axis arranged vertically.
Frustulia gibsonea, found at Gibson Lake, Renfrew County. Examples: 1) (112 µm x 22 µm); 2) (95 µm x 19 µm); 3) (92 µm x 18 µm). Image: Joe Holmes & Andréanne Bouchard © Canadian Museum of Nature.
This image is a black and white electron micrograph of a single diatom. It is oval-shaped, with the longer axis arranged diagonally. There is a dark groove in the centre of the diatom.
Detailed SEM image of Frustulia gibsonea (66 µm x 16 µm), magnified 3,500x. Image: Andréanne Bouchard © Canadian Museum of Nature

Finding multiple new species in one sample is exciting and rare. As diatom researchers continue to collect fresh and marine water samples from across Canada and around the world, new diatom species will no doubt be discovered.