Ocean acidification

Definition

Ocean acidification refers to the process by which the pH of ocean waters decreases due to the absorption of excess atmospheric carbon dioxide (CO2). As CO2 dissolves in seawater, it forms carbonic acid, which lowers the pH and disrupts the natural chemistry of ocean ecosystems. This phenomenon significantly affects marine life, particularly organisms with calcium carbonate structures, and has broader implications for microbial communities within these environments.

5 Must Know Facts For Your Next Test

1. The increase in atmospheric CO2 due to human activities, like fossil fuel burning and deforestation, is the primary driver of ocean acidification.
2. Ocean acidification can lead to decreased growth and survival rates in calcifying organisms, impacting food webs and biodiversity.
3. Microbial communities in the ocean are affected by acidification, as changes in pH can alter their composition and function.
4. Some species may adapt to changing pH levels, but many others are at risk of extinction due to their inability to cope with rapid changes.
5. Ocean acidification can also affect ecosystem services provided by marine environments, such as fisheries and carbon cycling.

Review Questions

• How does ocean acidification impact microbial communities in marine ecosystems?
  • Ocean acidification impacts microbial communities by altering the pH levels in seawater, which can change the composition and functioning of these communities. As the acidity increases, certain microbial species may thrive while others decline, leading to shifts in nutrient cycling and energy flow. These changes can have cascading effects on larger marine organisms and overall ecosystem health.
• Discuss the implications of ocean acidification on calcifying organisms and their role in marine food webs.
  • Calcifying organisms, such as corals and shellfish, are particularly vulnerable to ocean acidification because they rely on calcium carbonate to build their structures. The decreased availability of carbonate ions due to lowered pH hampers their growth and survival. This decline not only affects these species but also disrupts marine food webs since many fish and other marine animals depend on these organisms for habitat and food, ultimately threatening biodiversity.
• Evaluate the potential long-term effects of ocean acidification on marine ecosystems and global climate processes.
  • The long-term effects of ocean acidification could be severe for marine ecosystems and global climate processes. As key species decline or go extinct, entire ecosystems may shift or collapse, leading to a loss of biodiversity and altered biogeochemical cycles. Additionally, disrupted marine environments can impact global carbon cycles by reducing the ocean's ability to act as a carbon sink. These changes could have far-reaching implications for food security, economic stability, and climate regulation on a global scale.

Related terms

pH:

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

carbon sequestration: The process of capturing and storing atmospheric CO2, often through natural processes like photosynthesis or artificial methods.

calcifying organisms: Marine organisms, such as corals and mollusks, that build their shells and skeletons from calcium carbonate and are vulnerable to changes in ocean acidity.