WISRD Research & Engineering Journal

The top of the plug is approximately 6.4 mm in diameter with a stem that is approximately 31.8 mm long. The plugs are designed to fit into a plastic frag rack. Each plug was marked with a sharpie to keep the orientation facing the camera the same if the plug needed to be moved, or if it was moved by a wayfaring snail (Figure 3) or a water current and needed to be repositioned. Snails are a necessary component of the tank to mitigate algal growth, so their presence must be accommodated.

Figure 3 . Snail moving over the rack surface (cleaning off algae) bumps into a fragment and alters its position. 2.2 Frag Racks Initially, fragment plugs were supported by placing them in plastic micro test tube racks that were on hand in the lab (Figure 4) as our first so called “frag rack”. The test tube racks were useful, but they were easily bumped, which resulted in a change of camera angle, and they were hard to level in the sand due to their large surface area. To solve this problem, we chose a large off-the-shelf egg carton rack for its ability to be secured at a fixed point within the tank. It was crucial that fragments retained their positions for meaningful analysis of growth.

Figure 4 . Left: Microtest tube rack Initially used to hold ceramic plugs. Right: Population of propagated Green Star Polyps held in an egg carton frag rack as they grow.

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