Glossary
Calcium Carbonate (CaCO3)
A crucial mineral compound used by many marine organisms, such as corals, mollusks, and plankton, to build their shells, skeletons, and other protective structures.
Example:
Coral reefs, vital marine ecosystems, are primarily built from calcium carbonate secreted by tiny coral polyps.
Carbon Dioxide (CO2)
A greenhouse gas released into the atmosphere, primarily from human activities like burning fossil fuels, that dissolves in seawater and initiates ocean acidification.
Example:
The increased amount of carbon dioxide released from industrial processes is the main driver behind the ocean's decreasing pH.
Carbonic Acid (H2CO3)
An acid formed when carbon dioxide (CO2) dissolves in seawater, which then dissociates to release hydrogen ions (H+).
Example:
When atmospheric CO2 enters the ocean, it reacts with water to form carbonic acid, a key step in the acidification process.
Deforestation
The clearing of forests for other land uses, which contributes to increased atmospheric CO2 by reducing the number of trees that absorb carbon dioxide through photosynthesis.
Example:
Extensive deforestation in tropical regions not only destroys biodiversity but also diminishes the Earth's natural capacity to remove CO2 from the atmosphere.
Food Chain
A hierarchical series of organisms each dependent on the next as a source of food, illustrating the flow of energy and nutrients within an ecosystem.
Example:
The decline of shell-building organisms at the base of the marine food chain due to ocean acidification can have cascading negative effects on higher trophic levels.
Fossil Fuels
Carbon-rich energy sources, such as coal, oil, and natural gas, formed from the remains of ancient organisms, whose combustion is a major contributor to increased atmospheric CO2.
Example:
The burning of fossil fuels for transportation and electricity generation is a primary human activity contributing to ocean acidification.
Hydrogen Ions (H+)
Ions released by carbonic acid in seawater, which increase the acidity of the ocean by lowering its pH and reducing the availability of carbonate ions.
Example:
The rising concentration of hydrogen ions in the ocean makes it more challenging for marine organisms to build and maintain their calcium carbonate structures.
Hypoxic Environments
Areas in aquatic ecosystems characterized by very low levels of dissolved oxygen, often resulting from excessive plant growth (eutrophication) and subsequent decomposition.
Example:
While some marine plants may thrive in CO2-rich waters, their eventual decay can lead to hypoxic environments, creating 'dead zones' harmful to most marine life.
Ocean Acidification
The ongoing decrease in the pH of the Earth's oceans, primarily caused by the absorption of excess atmospheric carbon dioxide (CO2).
Example:
Scientists are observing that the Pacific Northwest's oyster farms are struggling due to ocean acidification, which makes it harder for young oysters to form their shells.
Physiological Stress
Adverse internal conditions experienced by organisms due to environmental changes, such as increased acidity, affecting their overall health, behavior, and survival.
Example:
Fish in more acidic waters can experience physiological stress, impairing their sense of smell and making them less able to find food or avoid predators.
Pteropods
Tiny sea snails, also known as 'sea butterflies,' that form a critical base of the marine food web and whose calcium carbonate shells are highly vulnerable to dissolution in acidic waters.
Example:
The potential collapse of pteropod populations due to ocean acidification poses a severe threat to the many species, including whales and salmon, that rely on them for food.
Shell Formation
The biological process by which marine organisms create and maintain their calcium carbonate shells or skeletons, which is hindered by increased ocean acidity.
Example:
Ocean acidification makes shell formation more difficult for organisms like clams and oysters, leading to weaker or malformed shells.
pH Scale
A logarithmic scale ranging from 0 to 14 that measures the acidity or alkalinity of a solution, where lower numbers indicate higher acidity.
Example:
Even a small drop in the ocean's pH scale represents a significant increase in acidity, impacting marine life profoundly.