Ocean acidification

Definition

Ocean acidification is the process whereby the ocean becomes more acidic due to the increased absorption of atmospheric carbon dioxide (CO2). As CO2 levels rise, it reacts with seawater to form carbonic acid, leading to a decrease in pH levels, which can adversely affect marine life and ecosystems.

5 Must Know Facts For Your Next Test

1. Ocean acidification has led to a significant decrease in the availability of carbonate ions, which are essential for calcifying organisms like corals and shellfish to form their shells and skeletons.
2. The current rate of ocean acidification is unprecedented in at least 300 million years, primarily driven by human-induced CO2 emissions from fossil fuel combustion.
3. By the end of this century, ocean acidity is projected to increase by 150% if current CO2 emission trends continue, which will have severe consequences for marine biodiversity.
4. Changes in ocean chemistry can disrupt marine food webs, as many species rely on calcifying organisms for habitat and as a primary food source.
5. Ocean acidification also poses economic risks for communities that depend on fisheries and aquaculture, as declining populations of shellfish and other marine species can affect livelihoods.

Review Questions

• How does ocean acidification impact marine ecosystems and what are some examples of affected organisms?
  • Ocean acidification primarily impacts marine ecosystems by lowering pH levels, which can harm calcifying organisms such as corals, mollusks, and certain plankton species. These organisms struggle to build their shells and skeletons due to reduced carbonate ion availability. This not only affects individual species but also disrupts entire food webs and ecosystem structures, leading to broader ecological consequences.
• Discuss the role of human activity in ocean acidification and its connection to the carbon cycle.
  • Human activities, particularly the burning of fossil fuels and deforestation, release significant amounts of CO2 into the atmosphere. A large portion of this CO2 is absorbed by the oceans, where it reacts with seawater to form carbonic acid. This process links ocean acidification directly to the carbon cycle, illustrating how anthropogenic emissions influence ocean chemistry and environmental health.
• Evaluate the potential long-term effects of ocean acidification on global fisheries and economies that depend on marine resources.
  • Long-term effects of ocean acidification on global fisheries could be devastating as key species like shellfish face population declines due to impaired growth and reproduction. This not only threatens biodiversity but also poses economic risks for communities reliant on fishing and aquaculture. As shellfish populations dwindle, prices could rise dramatically, affecting food security and livelihoods. The ripple effects could lead to increased competition for resources and changes in community dynamics as reliance on marine resources shifts.

Related terms

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

pH scale: A logarithmic scale used to specify the acidity or basicity of an aqueous solution, where lower values indicate higher acidity.

calcifying organisms: Marine organisms that build shells or skeletons from calcium carbonate, which can be adversely affected by lower pH levels.