Ocean acidification

Definition

Ocean acidification refers to the process where the ocean becomes more acidic due to increased levels of carbon dioxide (CO2) in the atmosphere, which is absorbed by seawater. This change in pH affects marine ecosystems, altering the chemical composition of seawater and impacting marine life, particularly organisms that rely on calcium carbonate for their shells and skeletons.

5 Must Know Facts For Your Next Test

1. Since the beginning of the Industrial Revolution, the oceans have absorbed about 30% of the emitted CO2, leading to an approximate 0.1 decrease in ocean pH, making it more acidic.
2. Ocean acidification poses a threat to coral reefs, as higher acidity hampers their ability to produce calcium carbonate, essential for their growth and structure.
3. The decrease in pH can disrupt marine food webs by affecting the survival rates of plankton, which serve as a foundational food source for many marine species.
4. Some fish species may also be impacted by ocean acidification as it can affect their behavior and sensory functions, making them more vulnerable to predators.
5. The impacts of ocean acidification are not uniform globally; different regions may experience varying degrees of acidity based on local environmental factors such as temperature and salinity.

Review Questions

• How does the increase in atmospheric carbon dioxide contribute to ocean acidification, and what are its immediate effects on marine ecosystems?
  • The increase in atmospheric carbon dioxide results from human activities like fossil fuel combustion, leading to higher CO2 levels being absorbed by oceans. This process lowers the pH of seawater, making it more acidic and affecting marine ecosystems. Immediate effects include disruptions to organisms that rely on calcium carbonate for their shells and skeletons, as well as potential changes in species distribution and food web dynamics.
• Discuss how ocean acidification could impact coral reef health and biodiversity in marine ecosystems.
  • Ocean acidification negatively affects coral reef health because increased acidity impairs coral's ability to produce calcium carbonate, which is crucial for maintaining their structure. As corals struggle to grow and thrive, this can lead to diminished biodiversity since many marine species depend on coral reefs for habitat and food. The decline of coral reefs can result in a cascading effect on the entire marine ecosystem, impacting various species reliant on healthy reefs.
• Evaluate the long-term consequences of ocean acidification for global fisheries and coastal communities dependent on marine resources.
  • The long-term consequences of ocean acidification could severely affect global fisheries due to declining fish populations and alterations in species distribution caused by changing ocean chemistry. Coastal communities that rely heavily on fishing for their livelihoods may face economic challenges as fish stocks diminish. Additionally, these changes could impact local food security and alter traditional fishing practices, requiring adaptation strategies to manage these new challenges effectively.

Related terms

Carbon dioxide: A greenhouse gas produced by human activities such as burning fossil fuels, which contributes to climate change and ocean acidification when absorbed by oceans.

pH scale: A measure of how acidic or basic a solution is, where lower values indicate higher acidity; ocean acidification typically lowers the pH of seawater.

Calcium carbonate: A chemical compound that forms the shells and skeletons of many marine organisms, which can be affected by changes in ocean acidity.