Which microscopic plankton has a silica-based skeleton and is used in paleoceanography as indicators?

Which microscopic plankton has a silica-based skeleton and is used in paleoceanography as indicators?

• A. Nodule
• B. Sand
• C. Pteropod
• D. Radiolarian

Answer: (D)

Siliceous skeletons and their use in reading past oceans. Radiolarians are tiny marine protozoa that build intricate skeletons from silica. When they die, these silica tests fall to the seafloor and become well-preserved microfossils in sediments. Because different radiolarian species prefer different water masses, temperatures, and nutrient conditions, scientists analyze their species composition and abundances in sediment layers to infer past ocean conditions and circulation. This silica-based shell is a key reason radiolarians are especially useful in paleoceanography. The other options don’t fit: a nodule is a mineral lump on the seafloor, sand is a sediment, and pteropods have calcium carbonate shells rather than silica.

Siliceous skeletons and their use in reading past oceans. Radiolarians are tiny marine protozoa that build intricate skeletons from silica. When they die, these silica tests fall to the seafloor and become well-preserved microfossils in sediments. Because different radiolarian species prefer different water masses, temperatures, and nutrient conditions, scientists analyze their species composition and abundances in sediment layers to infer past ocean conditions and circulation. This silica-based shell is a key reason radiolarians are especially useful in paleoceanography. The other options don’t fit: a nodule is a mineral lump on the seafloor, sand is a sediment, and pteropods have calcium carbonate shells rather than silica.