Ocean acidification

Definition

Ocean acidification refers to the process by which the ocean becomes more acidic due to increased levels of carbon dioxide (CO2) in the atmosphere. When CO2 is absorbed by seawater, it reacts with water to form carbonic acid, leading to a decrease in pH levels. This phenomenon is closely linked to climate change, as rising global temperatures and increased CO2 emissions are driving both ocean acidification and broader environmental shifts.

5 Must Know Facts For Your Next Test

1. Since the Industrial Revolution, ocean surface pH has decreased by about 0.1 units, indicating a significant increase in acidity.
2. Ocean acidification can negatively affect marine organisms, particularly those with calcium carbonate shells or skeletons, such as corals and some shellfish, making it harder for them to grow and survive.
3. The process can also disrupt marine food webs, as many species rely on calcifying organisms for food and habitat.
4. In addition to biological impacts, ocean acidification can influence global carbon cycling by affecting how much CO2 is stored in oceans.
5. Efforts are being made to mitigate ocean acidification by reducing carbon emissions and increasing awareness of its potential impacts on marine life and human economies.

Review Questions

• How does ocean acidification occur and what role does carbon dioxide play in this process?
  • Ocean acidification occurs when carbon dioxide (CO2) emitted from human activities is absorbed by seawater. This CO2 reacts with water to form carbonic acid, which dissociates into bicarbonate and hydrogen ions, leading to a decrease in pH levels. The increase in hydrogen ions results in a more acidic ocean environment, negatively affecting marine life that relies on stable pH levels for survival.
• Discuss the implications of ocean acidification on marine ecosystems and the organisms that inhabit them.
  • Ocean acidification poses serious threats to marine ecosystems by affecting organisms that rely on calcium carbonate for their shells and skeletons, such as corals, mollusks, and some plankton species. As pH levels drop, these organisms struggle to calcify, impacting their growth and survival. This disruption can lead to shifts in species composition and biodiversity within marine habitats, ultimately influencing the entire food web and ecosystem stability.
• Evaluate the potential socioeconomic impacts of ocean acidification on coastal communities and industries reliant on marine resources.
  • Ocean acidification can have significant socioeconomic impacts on coastal communities that depend on fishing, aquaculture, and tourism related to healthy marine ecosystems. Declines in shellfish populations due to increased acidity can threaten livelihoods in fishing industries, while coral reef degradation can reduce tourism revenue. Additionally, changes in marine biodiversity may disrupt local fisheries and food security, making it essential for communities to adapt and develop strategies for resilience against these changing conditions.

Related terms

carbon cycle: The series of processes through which carbon compounds are interconverted in the environment, including the absorption of CO2 by oceans.

pH scale: A logarithmic scale used to measure the acidity or alkalinity of a solution, with lower values indicating higher acidity.

marine ecosystems: Complex communities of organisms and their physical environment in oceans and seas, which are impacted by changes in water chemistry due to acidification.