Alcyoneus calidi
Alcyoneus calidi is a colonial single-celled photosynthetic producer. Most colonies live in shallow waters no deeper than 50m because they’re dependent on light for photosynthesis. A. calidi colonies excrete silica forming spires which contain suitable microclimates for A. calidi within the water. The silica is translucent so light can still reach the cells. The silica spires are formed from the top down, new silica is fixed on the bottom of a spire. The spires are formed in thin layers with the cells living between the layers. There are pores or openings left in the spire structure to allow water to flow in. The temperature within the spire usually stays around 22-24°C.
Individual A. calidi cells are 20μm long and the colonies are usually 5-10m tall by 1-2m wide. A. calidi have mitochondria, ribosomes, a nucleus, protein transport systems, a cell wall, thylakoids, and vacuoles. A. calidi reproduces by mitosis and new colonies will be formed from fragmentation.