Ocean acidification

Definition

Ocean acidification is the process whereby the pH levels of the ocean decrease due to the absorption of excess carbon dioxide (CO2) from the atmosphere. This phenomenon leads to a more acidic ocean environment, impacting marine life, particularly organisms that rely on calcium carbonate for their shells and skeletons. The effects of ocean acidification are significant, especially during periods of mass extinction, as they disrupt marine ecosystems and food webs.

5 Must Know Facts For Your Next Test

1. Ocean acidification is primarily driven by increased atmospheric CO2 levels due to human activities such as fossil fuel combustion and deforestation.
2. The decrease in pH levels can hinder the ability of marine organisms like corals and shellfish to produce their calcium carbonate structures, leading to weaker shells and skeletons.
3. As ocean acidity increases, it can disrupt marine food webs by affecting phytoplankton growth, which serves as a foundational food source for many marine species.
4. The End-Triassic extinction was partly influenced by volcanic activity that released large amounts of CO2, contributing to both global warming and ocean acidification during that time.
5. Long-term consequences of ocean acidification include potential loss of biodiversity in marine ecosystems and altered fishery dynamics due to changes in species composition.

Review Questions

• How does ocean acidification affect marine organisms, specifically those with calcium carbonate structures?
  • Ocean acidification negatively impacts marine organisms that depend on calcium carbonate for their shells and skeletons. As pH levels decrease, it becomes more difficult for these organisms to extract the necessary calcium carbonate from seawater. This can lead to thinner shells and weaker structures, making them more susceptible to predation and environmental stressors. Ultimately, this can result in reduced populations and biodiversity within marine ecosystems.
• Discuss the relationship between volcanic activity during the End-Triassic extinction and its impact on ocean chemistry.
  • During the End-Triassic extinction, extensive volcanic activity released significant amounts of CO2 into the atmosphere, which was subsequently absorbed by the oceans. This led to increased ocean acidity as pH levels dropped dramatically. The shift in ocean chemistry created hostile environments for many marine species, particularly those reliant on calcium carbonate, contributing to their decline and further exacerbating the extinction event.
• Evaluate the long-term ecological implications of ocean acidification on marine biodiversity and fisheries.
  • The long-term ecological implications of ocean acidification on marine biodiversity and fisheries are substantial. As acidic conditions persist, species that cannot adapt may face extinction, leading to a decrease in biodiversity. Additionally, alterations in species composition can disrupt existing food webs and ecosystem functions. Fisheries reliant on vulnerable species may also suffer economically as their populations decline or shift geographically, creating challenges for food security and livelihoods dependent on healthy marine ecosystems.

Related terms

calcium carbonate: A chemical compound (CaCO3) that is essential for the formation of shells and skeletons in marine organisms like corals, mollusks, and some plankton.

carbon cycle:

The natural process through which carbon is exchanged among the atmosphere, oceans, soil, and living organisms, influencing climate and ocean chemistry.

pH scale: A logarithmic scale used to specify the acidity or basicity of an aqueous solution, ranging from 0 (very acidic) to 14 (very basic), with 7 being neutral.