[text] Opposites. Wet & Dry.
[narrator] The Canadian Museum of Nature's natural history collection contains over 14.6 million specimens.
Most of these come from terrestrial or aquatic environments.
Wet or dry, they both need to be prepared and cared for in a very specific manner.
Let's take a peek inside the collections and discover some of these amazing specimens and preservation techniques.
[Jean-Marc Gagnon, Ph.D. Chief Scientist and Currator, Invertebrate Collections] A good contrast that we find in our collection is the preservation of specimens between dry and wet.
So dry specimens, like for example these shells, is easy to preserve. Not a big issue to store.
But when the animal is still in the shells, the tissue—the meat, if you want—then we have to preserve it with a chemical.
In most cases, what we use is ethanol. Ethanol is perfect for keeping the animal—the tissue—for a long time.
And we also use formaldehyde. Formaldehyde is more of a fixative, which will make the meat, the muscle, a little bit stronger, will be more resistant.
The main challenge with these two chemicals is that we cannot preserve DNA.
[Marie-Hélène Hubert, Collections Technician, Vertebrates] One of the challenges here at the museum is getting whole, fleshy specimens into dry skeletons.
We use different techniques in order to do that. We use hot and cold maceration, a process in which we
cover the specimens in water, cook them really slowly and extract oil that might be hidden inside the bones.
Or dermestid colonies as well can help. The dermestid colony is an insect colony that cleans the bones by eating the flesh off of the specimen.
One of the most problematic specimens to clean are the whale bones. It's a very fine balance to get the oil out so that it doesn't
have too much accumulated on top and becomes moist and attracts pests, or that it becomes too dry and becomes brittle.
A good example of the processes we used here at the museum is the blue whale downtown.
It was buried for eight years and treated with enzymes for six months and it's still seeping oil.
[Jennifer Doubt, Curator, Botany] Whether our plant and lichen specimens are stored wet, in liquid preservative, or dry,
on herbarium sheets, in envelopes or in boxes, doesn't necessarily match up with where they grew in nature.
We have a lot of marine and freshwater micro-algae in liquid. That's because they're so small you can't even see them without a microscope.
On the other hand, these seaweeds were once anchored in the ocean. We dried them out
in a plant press, or in a paper bag, and we're keeping them dry so they'll be useful for centuries.
These days, when museum researchers collect plants for the herbarium, they also collect a few leaves or stems from the same plant in silica gel.
The silica gel dries them out even faster than they would dry in a press, preserving DNA and other molecules for lab analysis.
[Aaron Lussier, Ph.D. Research Scientist, Mineralogy] What I have here is an example of a mineral that we might consider wet and a mineral that we might consider dry.
This mineral here is pryoxene, whereas this one is an amphibole.
Their compositions are fairly similar. Their atomic structures are fairly similar as well.
But they contain one key difference. This one (amphibole) has water inside of it, and this one (pyroxene) does not, making this one wet and this one dry.
And that's significant because as we all know, water is very sensitive to temperature.
At high temperatures, it prefers to be a gas. At low temperatures, it prefers to be a solid like ice.
When a magma crystallizes at depth in the Earth, it can do this over a very long period of time.
And it starts to crystallize the high-temperature minerals faster. The high-temperature minerals (pyroxene) are usually lacking in water,
whereas the lower temperature minerals (amphibole) tend to incorporate more water.
So what we know by looking at these two minerals is the amphibole likely crystallized at a slightly lower temperature than did the pyroxene.
[narrator] Wet or dry, museum staff take great pride in caring for Canada's natural-history collection, ensuring that it retains its scientific value for centuries to come.