Question

Organic limestone forms when marine organisms such as corral, clams, oysters and plankton remove chemical components of the minerals ------- and ---------- from organic water

Answer 1

Marine organisms like coral and clams form organic limestone by removing calcium and bicarbonate ions from seawater to create calcium carbonate, which then accumulates and lithifies into limestone over geological timescales.

Step-by-step explanation:

Organic limestone forms when marine organisms such as coral, clams, oysters, and plankton extract chemical components from seawater to construct their shells and skeletons. The two primary components these organisms remove from the seawater are calcium (Ca2+) and bicarbonate (HCO3−) ions. These ions combine to form calcium carbonate (CaCO3), which is the main constituent of limestone.

Over time, as these organisms die, their calcareous skeletal fragments accumulate on the ocean floor, forming sedimentary layers. With further geologic processes such as lithification, these layers harden and turn into limestone rock. Chalk limestone is a notable example, consisting of microscopic marine organisms like foraminifera and coccoliths.

Marine organisms play a crucial role in the carbon cycle by converting bicarbonate ions in the ocean into solid calcium carbonate forms, thereby creating significant carbon reservoirs in the form of limestone.