ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Why carbon dioxide in the oceans is a problem

Updated on May 20, 2016

Is there CO2 in the oceans?

Carbon dioxide (CO2) is a greenhouse gas (GHG) that has been implicated in causing climate change. We generally know this but what is less known is that increasing CO2 in the oceans is a big a problem as climate change. Perhaps not many people realize that oceans absorb atmospheric CO2. Even less realize that increasing CO2 in the oceans is actually a big problem.

Oceans and the carbon cycle

When CO2 is released into the atmosphere (whether it is a natural emission or human-induced emission) some of it stays there but some of it is cycled to other areas of the globe. Organisms, especially plants, uptake some of this CO2. Forests, for example, are carbon sinks where they can absorbed more carbon than they emit. Soils also act as a carbon sinks leading to some governments undertaking programs for farmers to take up carbon in their soil for carbon credits. This is also known as carbon farming.

But the oceans actually absorbed a very significant proportion. Approximately one third, or 30%, of the CO2 that is emitted into the atmosphere is absorbed by oceans. Therefore, with increasing amount of CO2 in the atmosphere, there is also an increasing amount of CO2 in the oceans.


The process of ocean acidification

Ocean acidification is explained in detail elsewhere. Briefly, CO2 entering the ocean becomes dissolved and changes the water chemistry. When CO2 reacts with water it forms carbonic acid which then dissociates into hydrogen ions and bicarbonate ions. When hydrogen ions increase in a solution, the pH decreases or becomes more acidic. So increasing CO2 in the ocean is decreasing the pH and leading to ocean acidification.

More precisely, increasing CO2 is leading the oceans to become less alkaline. In pre-industrial times, the pH of the ocean was 8.2. Today, the pH of the oceans is approximately 8.1. By the year 2100 it is predicted to be approximately 7.8. Therefore, the oceans are not becoming a sea of acid, rather a sea of less alkalinity.

Ocean acidification explained in 2 minutes

Small changes, big problems

Oceans with less alkalinity doesn’t sound as scary as ocean acidification. Additionally, a change in pH from 8.2 to 7.8 seems rather trivial. But scientific evidence shows that even this small shift in ocean pH can lead to big problems.

Ocean acidification is leading to a decrease in carbonic ions in the oceans. This ion is critical for many marine organisms to form their hard shells and skeletons. Developing a strong body for organisms such as corals, molluscs and crustaceans will become a problem. If these organisms cannot survive, then it could lead to wider ecological and ecosystem issues. For example, thousands of species, including humans, depend on corals. If corals should collapse, then this will lead to significant environmental problems.


Research shows ocean acidification is already a problem

Scientists have been performing many experiments on how future changes in ocean acidification will impact on marine organisms, although some caution has been expressed over the validity of experimental parameters in certain experiments. For example, in near-shore ocean environments, particularly where there is extensive seagrass vegetation, pH can vary quite widely.

Recently, the journal Nature published research showing that current levels of ocean pH is already having a significant impact on coral reefs. The unique experiment was conducted on a naturally occurring coral reef on the Great Barrier Reef off the coast of eastern Australia. As most ocean acidification experiments in the laboratory decrease pH, in this instance the scientists actually increased pH (that is, they made the oceans more alkaline). The motivation to increase the alkalinity of the ocean was to return the pH to levels that were observed prior to the industrial revolution.

The scientists found that the marine organisms in the pre-industrial ocean grew better skeletons and were more robust than the marine organisms in the modern ocean. The experiment demonstrated that changes in the oceans caused by an increase in atmospheric CO2 is not something that will occur in the future. Rather, the process of ocean acidification is occurring now.

Coral reefs and climate change

Reef building corals are the most vulnerable

Ocean acidification will affect many different types of species. However, emphasis has been given to reef building corals and their vulnerability to changes in ocean pH. As already described, a decrease in the ocean's pH will make it harder for corals to form skeletons. But other changes, occurring along with ocean acidification, are increasing the possibility of reef building coral extinction.

Temperature is another big environmental change in the oceans that will affect corals. Increasing temperature leads to organism stress and events such as coral bleaching. Direct human impacts, such as dredging for coal mines, as well as the impacts of invasive species, such as the crown of thorns star fish, are also making coral reefs vulnerable.

Coral bleaching - before and after



CO2 is not only a problem for climate change, but it is also a problem for the earth's oceans. Increasing CO2 is leading to ocean acidification which, in turn, is causing a range of ecological and environmental problems for marine life.


Submit a Comment

No comments yet.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)