---
title: "Calcium Carbonate — AP Enviro Definition & Exam Guide"
description: "Calcium carbonate (CaCO₃) is the compound corals and shellfish use to build skeletons, and ocean acidification threatens it. Learn how it shows up on the AP Enviro exam."
canonical: "https://fiveable.me/ap-enviro/key-terms/calcium-carbonate"
type: "key-term"
subject: "AP Environmental Science"
---

# Calcium Carbonate — AP Enviro Definition & Exam Guide

## Definition

Calcium carbonate is a chemical compound that is commonly found in rocks, shells, and the skeletons of marine organisms. It is an important component of many natural structures and plays a crucial role in various biological processes.

## Related Study Guides

- [1.4 The Carbon Cycle](/ap-enviro/unit-1/carbon-cycle/study-guide/DgNVtqUbzmk6j54jVo7q)
- [9.7 Ocean Acidification](/ap-enviro/unit-9/ocean-acidification/study-guide/F3GVfuEfIQERLREg0lk4)

## Review

### Related Terms

- [Marine Life](/ap-enviro/key-terms/marine-life): Marine life refers to all living organisms that inhabit oceans, seas, and other saltwater environments. These include fish, whales, dolphins, corals, and many other species.
- [Corals](/ap-enviro/key-terms/corals): Corals are marine animals that belong to the phylum Cnidaria. They form colonies made up of individual polyps that secrete calcium carbonate skeletons which contribute to coral reefs.
- [Carbon Cycle](/ap-enviro/key-terms/carbon-cycle): The carbon cycle is the process by which carbon moves between living organisms (through photosynthesis and respiration) and non-living components (such as rocks or the atmosphere) on Earth. It plays a vital role in regulating Earth's climate system.