Consequences of Ocean Acidification

Front

Ocean Acidification Noun

---

[oh-shun uh-sid-i-fi-kay-shun]

Back

Ocean Acidification

---

The ongoing decrease in the pH of the Earth's oceans, caused by the uptake of carbon dioxide from the atmosphere.

---

Example: This image compares a healthy sea snail shell to one damaged by acidic water, showing how ocean acidification dissolves shells and harms marine animals.

Front

Hydrogen ion (H+) Noun

---

[hy-druh-jen eye-on]

Back

Hydrogen ion (H+)

---

A positively charged ion whose concentration determines a solution's acidity, with more ions leading to a lower pH.

---

Example: A water molecule (H₂O) is shown splitting apart (dissociating) into a separate, positively charged hydrogen ion (H+) and a negatively charged hydroxide ion (OH-).

Front

Calcification Noun

---

[kal-si-fi-kay-shun]

Back

Calcification

---

The process by which marine organisms use calcium and carbonate ions to build their shells and skeletons out of calcium carbonate.

---

Example: This diagram shows how a coral polyp builds its hard skeleton in a process called calcification, by adding new material both vertically and laterally.

Front

Carbonate ion (CO32-) Noun

---

[kar-buh-neyt eye-on]

Back

Carbonate ion (CO32-)

---

An ion essential for shell and skeleton formation in marine life, which becomes less available as ocean acidity increases.

---

Example: This image shows how a carbonate ion (center) is used up when it reacts with carbon dioxide and water, a key process in ocean acidification.

Front

Calcite Noun

---

[kal-sahyt]

Back

Calcite

---

A common, stable crystal form (polymorph) of calcium carbonate used by many marine organisms to build their shells.

---

Example: Mussels build their protective shells by growing layers of calcite, a mineral that is vulnerable to dissolving in more acidic ocean water.

Front

Aragonite Noun

---

[uh-rag-uh-nahyt]

Back

Aragonite

---

A harder but less stable and more soluble crystal form of calcium carbonate used by some marine organisms for their shells.

---

Example: This diagram shows a cross-section of a mussel shell, revealing that the inner layer is made of aragonite, a material vulnerable to ocean acidification.

Front

Calcium Carbonate (CaCO3) Noun

---

[kal-see-um kar-buh-neyt]

Back

Calcium Carbonate (CaCO3)

---

The chemical compound used by marine organisms to form shells and skeletons, which can dissolve in more acidic conditions.

---

Example: This diagram shows that a calcium ion and a carbonate ion combine to form the compound calcium carbonate, the material used by marine life for shells.

Front

Carbonic Acid (H2CO3) Noun

---

[kar-bon-ik as-id]

Back

Carbonic Acid (H2CO3)

---

A weak acid formed when carbon dioxide dissolves in water, which releases hydrogen ions and drives ocean acidification.

---

Example: This diagram shows how a water molecule (H2O) and a carbon dioxide molecule (CO2) combine to form one molecule of carbonic acid (H2CO3).

Front

Hydrogen Carbonate ion (HCO3-) Noun

---

[hy-druh-jen kar-buh-neyt eye-on]

Back

Hydrogen Carbonate ion (HCO3-)

---

An ion, also known as bicarbonate, formed when carbonic acid loses a proton or when carbonate ions gain one.

---

Example: This image shows a model of a hydrogen carbonate ion (HCO3-), which is made of hydrogen, carbon, and oxygen atoms bonded together.

Front

Buffering Noun

---

[buf-er-ing]

Back

Buffering

---

The chemical process by which a solution resists changes in pH, such as the ocean's carbonate system slowing acidification.

---

Example: This diagram shows a buffer solution absorbing most of the added acid (H⁺ ions), which resists a large drop in the solution's pH.