Phaeodarian skeletons: their role in silica transport to the deep sea.

The skeletons of phaeodarian Radiolaria transport and redistribute silica to the tropical deep oceans by dissolving in the water column and on the sea floor. The skeletons are initially solid but within a few days to months become progressively more porous while settling through the water column. Phaeodarian Radiolaria are rarely preserved in the bottom sediments; in contrast, polycystine Radiolaria are the dominant Radiolaria preserved in the fossil record. This preservational difference may be due to differences in skeletal constituents.

Variable porosity in siliceous skeletons: determination and importance.

Gas adsorption data were used to obtain the specific surface area and specific pore volume for a variety of biogenically precipitated silica semples. The results suggest that this material is finely divided and porous. This interpretation was corroborated by the use of transmission electron microscopy at magnifications up to 180,000.