Ocean acidification

Definition

Ocean acidification refers to the ongoing decrease in the pH levels of the Earth's oceans, primarily caused by the absorption of excess carbon dioxide (CO2) from the atmosphere. As CO2 levels rise due to human activities, more of it dissolves in ocean water, leading to a series of chemical reactions that increase hydrogen ion concentration, thus lowering pH. This process has significant implications for marine ecosystems, impacting species diversity and food webs, which are essential for ecological balance and human livelihoods.

5 Must Know Facts For Your Next Test

1. Ocean acidification has increased since the Industrial Revolution, with ocean surface pH dropping by about 0.1 units since 1750.
2. The ocean absorbs approximately 30% of the CO2 released into the atmosphere, acting as a buffer for climate change but causing detrimental effects on marine life.
3. Calcifying organisms, such as corals and mollusks, struggle to maintain their calcium carbonate structures in more acidic waters, leading to weaker shells and compromised ecosystems.
4. Ocean acidification can disrupt food webs by affecting the survival and growth rates of key species like plankton, which are foundational to marine food chains.
5. The impacts of ocean acidification are expected to worsen with continued fossil fuel emissions and climate change, posing risks to global fisheries and coastal communities.

Review Questions

• How does ocean acidification relate to the greenhouse effect and anthropogenic climate change?
  • Ocean acidification is directly linked to the greenhouse effect because it results from increased carbon dioxide emissions from human activities like burning fossil fuels. As CO2 accumulates in the atmosphere due to these activities, a significant portion is absorbed by the oceans, leading to a decrease in pH levels. This connection highlights the interdependence of atmospheric changes and oceanic conditions, as both are driven by the same root causes of climate change.
• What are some ecological consequences of ocean acidification on marine biodiversity?
  • Ocean acidification poses severe threats to marine biodiversity by negatively impacting calcifying organisms such as corals, mollusks, and some plankton species. As these organisms struggle to form their calcium carbonate structures in more acidic waters, entire ecosystems that depend on them for habitat and food sources may collapse. This disruption can lead to a loss of biodiversity as species that rely on these foundational organisms are affected, causing cascading effects throughout marine food webs.
• Evaluate potential conservation strategies that could mitigate the impacts of ocean acidification on marine ecosystems.
  • To address the challenges posed by ocean acidification, various conservation strategies can be implemented. These include reducing CO2 emissions through renewable energy sources and sustainable practices that minimize further atmospheric carbon buildup. Additionally, protecting critical habitats like coral reefs and mangroves can enhance ecosystem resilience against changing conditions. Restoration projects that focus on enhancing populations of calcifying organisms may also help counteract some effects of acidification. Ultimately, an integrated approach combining emission reductions and habitat protection is essential for preserving marine biodiversity in an era of climate change.

Related terms

pH: A measure of how acidic or basic a solution is, with lower values indicating higher acidity.

carbon cycle:

The biogeochemical cycle by which carbon is exchanged among the Earth's biosphere, pedosphere, geosphere, hydrosphere, and atmosphere.

calcifying organisms: Marine species that build shells or skeletons from calcium carbonate, such as corals and some types of plankton, which are highly vulnerable to ocean acidification.