Ocean acidification

Definition

Ocean acidification refers to the process by which the ocean becomes more acidic due to increased carbon dioxide (CO2) emissions from human activities, such as fossil fuel burning and deforestation. This phenomenon is significant because as CO2 levels rise in the atmosphere, more of it is absorbed by the ocean, leading to chemical reactions that lower the pH of seawater. The impact of ocean acidification affects marine ecosystems, particularly organisms that rely on calcium carbonate for their shells and skeletons, and has implications for climate change and human-induced alterations in Earth systems.

5 Must Know Facts For Your Next Test

1. The ocean absorbs approximately 30% of the CO2 emitted into the atmosphere, leading to a decrease in pH levels.
2. Since the beginning of the industrial era, ocean surface pH has decreased by about 0.1 units, which corresponds to a 30% increase in acidity.
3. Coral reefs are particularly vulnerable to ocean acidification, as lower pH levels hinder their ability to produce calcium carbonate for their structures.
4. Ocean acidification can disrupt food webs by affecting the survival and growth of key species such as plankton, which serve as a primary food source for many marine organisms.
5. The economic implications of ocean acidification are significant, impacting fisheries and aquaculture industries that rely on shellfish and other marine life sensitive to changing pH levels.

Review Questions

• How does ocean acidification result from human activities, and what are its primary environmental impacts?
  • Ocean acidification is primarily caused by the increased levels of carbon dioxide produced from human activities such as burning fossil fuels and deforestation. As CO2 enters the ocean, it reacts with water to form carbonic acid, leading to lower pH levels. This shift in acidity significantly impacts marine environments, especially organisms that depend on calcium carbonate for their shells, like corals and shellfish, threatening biodiversity and altering ecosystem dynamics.
• In what ways does ocean acidification challenge marine ecosystem resilience, particularly concerning biodiversity?
  • Ocean acidification poses a direct challenge to marine ecosystem resilience by disrupting the delicate balance of species interactions and habitats. Many marine organisms are adapted to specific pH levels; when these levels drop, it can lead to reduced growth rates and increased mortality among vulnerable species. As foundational species like coral reefs and shellfish decline, the overall biodiversity of marine ecosystems may suffer, compromising their ability to recover from environmental stresses.
• Evaluate the long-term implications of ocean acidification on global climate change and human societies reliant on marine resources.
  • The long-term implications of ocean acidification on global climate change are profound, as changes in marine ecosystems can alter carbon cycling processes crucial for regulating atmospheric CO2 levels. As vital species decline or disappear due to acidic waters, human societies dependent on fisheries and aquaculture face economic challenges that could destabilize food security. Furthermore, a decrease in biodiversity can reduce the resilience of marine ecosystems against other stressors related to climate change, ultimately compounding the risks associated with rising global temperatures.

Related terms

Carbon Dioxide (CO2): A colorless gas that is produced by burning fossil fuels and biomass, as well as through respiration; it is a significant greenhouse gas contributing to global warming and ocean acidification.

Calcium Carbonate: A chemical compound (CaCO3) that is essential for the formation of shells and skeletons in marine organisms like corals and some shellfish, which are affected by changes in ocean acidity.

Ecosystem Resilience: The ability of an ecosystem to withstand disturbances and maintain its essential functions; ocean acidification poses threats to the resilience of marine ecosystems.