Ocean acidification

Definition

Ocean acidification refers to the process by which the ocean becomes more acidic due to increased levels of carbon dioxide (CO2) absorbed from the atmosphere. This phenomenon is a direct result of human activities, such as burning fossil fuels, which elevate CO2 levels. As the oceans absorb this excess CO2, a chemical reaction occurs that lowers the pH of seawater, leading to detrimental effects on marine ecosystems, particularly organisms that rely on calcium carbonate for their shells and skeletons.

5 Must Know Facts For Your Next Test

1. Ocean acidification has increased the acidity of surface ocean waters by about 30% since the beginning of the Industrial Revolution.
2. As seawater becomes more acidic, it becomes more challenging for calcifying organisms to produce their calcium carbonate structures, leading to weaker shells and skeletons.
3. The effects of ocean acidification can disrupt marine food webs, impacting fish populations and human communities that rely on these resources for food and income.
4. Coral reefs are particularly vulnerable to ocean acidification as they struggle to maintain their calcium carbonate structures, which could lead to widespread reef degradation.
5. Long-term ocean acidification poses significant risks to biodiversity, with potential changes in species distribution and declines in marine biodiversity.

Review Questions

• How does ocean acidification impact calcifying organisms in marine ecosystems?
  • Ocean acidification negatively affects calcifying organisms by making it more difficult for them to form their calcium carbonate shells and skeletons. As the acidity of seawater increases, the availability of carbonate ions decreases, which are essential for these organisms to build their structures. This can lead to weaker shells and a decline in populations of species such as corals and mollusks, ultimately impacting the entire marine ecosystem that relies on these organisms.
• Discuss the broader implications of ocean acidification on marine biodiversity and fisheries.
  • Ocean acidification poses serious threats to marine biodiversity by altering habitats and disrupting food webs. Species that are sensitive to changes in pH may decline or face extinction, while others may thrive, leading to shifts in species composition. Fisheries that depend on healthy populations of fish and shellfish could be severely affected as key species struggle to survive or reproduce in more acidic conditions. This imbalance can have economic repercussions for communities reliant on fishing as a source of livelihood.
• Evaluate the relationship between human activities contributing to ocean acidification and climate change, and propose potential solutions to mitigate these effects.
  • Human activities such as fossil fuel combustion and deforestation significantly contribute to increased carbon dioxide levels in the atmosphere, which in turn leads to ocean acidification. Both climate change and ocean acidification stem from elevated CO2 levels, creating a dual threat to marine environments. To mitigate these effects, solutions could include reducing carbon emissions through renewable energy sources, improving energy efficiency, promoting sustainable fishing practices, and enhancing marine protected areas. These strategies aim not only to address climate change but also to safeguard marine ecosystems from further degradation.

Related terms

carbon dioxide (CO2): A colorless gas that is produced by burning fossil fuels and is a significant contributor to climate change and ocean acidification.

calcifying organisms:

Marine species such as corals, mollusks, and some plankton that build their shells and skeletons from calcium carbonate, which is affected by changes in ocean acidity.

marine ecosystem: An interconnected system of living organisms, their environment, and the physical and chemical conditions of the ocean.