Phytoplankton calcareous

In addition to undigested organic matter, fecal pellets also contain fragments of calcareous and siliceous hard parts and clay-sized grains of clay minerals. Fecal pellets can harbor viable bacterial and phytoplankton cells. Because of their fast sinking rates, fecal pellets reach the seafloor relatively intact. Their organic matter represents the major source of food for the benthos. 

Coccolithophorids Phytoplankton that deposit calcareous plates called coccoliths. 

Coccoliths Calcareous plates deposited by phytoplankton called coccolithophorids. 

Of all the phytoplankton species introduced to the Sea of Azov, only Pseudosolenia calcar-avis may cause negative effects on the sea ecosystem during its bloom. 

A shift in community composition may also be important to the biological pump if it is from a calcareous to a noncalcareous phytoplankton, as precipitation of CaCOs diminishes the ocean s ability to hold dissolved CO2. DIC (XCO2) is present in seawater as several species, dissolved CO2, carbonic acid, and the dissociated forms, bicarbonate ion, and carbonate ion ... 

Perhaps the best known of the mass extinctions is that associated with the demise of the dinosaurs at the Cretaceous—Tertiary boundary, which has been attributed to a meteorite impact (Alvarez et al. 1980 Kruge et al. 1994 Skelton et al. 2003), although natural climate change may also have been a factor. Planktonic organisms (particularly foraminiferans, calcareous phytoplankton and radiolarians) were also severely affected. On land, trees seem to have been devastated, with the recovery period marked by the proliferation of ferns. The pollen record is dominated by fern spores, and hence known as the fern spike, which is observed... 

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