Their shells are made out of silica (radiolaria (a, 350µm) and diatoms (b, 50µm); or out of calcium carbonate (foraminifera (c, 400µm) and coccoliths (d, 15µm). Is radiolarians zooplankton or phytoplankton? Radiolarians are exclusively open ocean, silica-secreting, zooplankton. They occur abundantly in major oceanic sites worldwide. What are radiolarians usedRead More →