Ocean acidification is a reduction in the ocean's pH over an extended period, caused by the ocean absorbing roughly 30 percent of the carbon dioxide released into the atmosphere. As seawater absorbs more CO2, chemical reactions raise hydrogen ion levels and reduce the carbonate ions that shell- and skeleton-building organisms such as oysters, clams and corals need to build and maintain their structures.
Facts
PeriodicityOngoing and cumulative since the Industrial Revolution, tracking more than two centuries of rising atmospheric carbon dioxide from fossil fuel burning and land use change, rather than a discrete or recurring event. 1 ScaleGlobal: affects the entire world ocean, including coastal estuaries and waterways, not one region alone. 1 First DescribedThe ocean has grown about 26 percent more acidic over the past 250 years, but ocean acidification became a named, actively studied field only in the early 2000s as CO2 monitoring and carbonate chemistry research matured; NOAA now runs a dedicated Ocean Acidification Program to track the trend. 2 Connections
Demonstrated By
Reef-building corals are among the organisms most cited as vulnerable to reduced carbonate availability from acidification.
Source Ocean Acidification (NOAA Ocean Service)
Source What Is Ocean Acidification (NOAA OA Program)
Open Questions
Source Ocean Acidification (NOAA Ocean Service)
In the Other Atlases
Same As
Also in Earth and Environment Atlas: the same subject.
Sources
1. Ocean Acidification (NOAA Ocean Service)
National Oceanic and Atmospheric AdministrationIntroduction
The ocean absorbs about 30 percent of the CO 2 that is released in the atmosphere, and as levels of atmospheric CO 2 increase, so do the levels in the ocean.
main content section
Ocean acidification is affecting the entire world's oceans, including coastal estuaries and waterways.
- In Category: Natural Phenomena
- Demonstrated By: Coral Reef Systems
View the Source 2. What Is Ocean Acidification (NOAA OA Program)
NOAA Ocean Acidification ProgramA Timeline of Evidence sectionQuote, A Timeline of Evidence section
Over the past 250 years, the ocean has become about 26% more acidic on average globally.
Ocean Acidification (NOAA PMEL)
NOAA Pacific Marine Environmental Laboratorysection headingQuote, section heading
Ocean Acidification: The Other Carbon Dioxide Problem
Open Questions (1 open question)
How severely and how quickly will continued ocean acidification affect shell- and skeleton-building marine life across different species?
The chemistry of ocean acidification is well established, but how various calcifying species and food webs will respond as pH continues to drop is still being actively researched.
What would resolve this Long-term, multi-species experiments and field observation tracking calcification rates and population effects as ocean pH continues to fall.
Marine chemistry and marine biologyOcean Acidification (NOAA Ocean Service)
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