How do we move from the residue remaining after a round of acid digestions to an isolated denticle ready for measurement and identification? It’s not as easy as it sounds.
As I peered down through the ocular of my microscope at the diverse array of particles illuminated by the bright light above, I spotted countless sponge spicules (minuscule glassy spears that compose their porous skeletons), fish teeth, bone fragments, otoliths (fish ear bones), and the occasional strand of organic material or remnant chunk of calcium carbonate. These stood out against the black gridded background of my metal picking dish, recounting the history of the menagerie of creatures that left their mark on this particular patch of sediment before it was collected from the reef. Paintbrush in hand, I was ready to begin. However, I would be painting no masterpieces today.
I spread a small scoop – maybe equivalent to the size of a pinch of salt – of my sediment sample out over the area of the picking dish, trying to evenly distribute it and produce a single layer of particles. Now came the fun yet tedious part. I began to manually brush through the particles, visually scanning them with care in hopes that a denticle would catch my eye. Each time I found one, a little flurry of excitement would well up within me and I would suddenly feel like I had the endurance to pick for five more hours (as well as the inspiration to write a blog post). It’s a seemingly endless treasure hunt, but my tiny yet precious haul of denticles validates every minute of the search.