Bryozoans, turntables, and 3D printing – oh my!

Latitude: -62 17.4243 Longitude: -058 08.3450

Many of the scientists onboard have their own specialties – animals that they research, prefer to handle, or know how to identify – anywhere from small critters that live between sand grains to those that are magnitudes of scale larger. My favorite group are the bryozoans, or moss animals, which are colonial and can form substantial structures from many, many individuals called zooids. For most marine bryozoans, each zooid is a U-shaped gut and a mouth surrounded by a ring of tentacles all inside a calcified box.

For me, one of the fascinating things about bryozoans is that they are hugely diverse! Colonies can encrust rocks, be flexible plant-like fronds, or grow into big ruffled structures. In Antarctica, many different genera have developed similar growth forms. This may make it a bit more difficult to do a quick identification by eye (without aid of a microscope), but it brings up the question – why? There are a few different possible causes, like ice scour, low metabolism, and food availability, but a small group of the science team are interested in questions regarding current and flow. Since bryozoans feed by filtering food out of the water, orientation of colony surfaces is important. What better way to investigate this than by scanning bryozoans we collect on the trip?

I’m using what’s called photogrammetry to do just that! Photogrammetry is done by taking photos of a specimen at different angles, then putting all the photos into software that will translate overlapping areas from 2D images into points that form a 3-dimensional structure. Luckily, our Marine Technicians have made this somewhat easier by fashioning a turntable, reducing the time it takes to get the images needed for modeling.

Not only does this allow us to have a digital version of various growth forms, it also opens up the possibility of making a 3D print of representative whole colonies. Prints can be used to see how water flows through and around the colony, perhaps giving additional insight into why Antarctic bryozoans grow like they do. Check out the pictures for a taste!\
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Megan McCuller
Collections Manager, Non-molluscan Invertebrates
North Carolina Museum of Natural History