What is the pH level of ocean water usually around?

The pH level of ocean water typically ranges from about 8.1 to 8.3, indicating that ocean water is slightly basic. This slight alkalinity is primarily due to the presence of bicarbonate ions formed from the dissolution of carbon dioxide in seawater, which buffers the changes in pH and helps maintain a stable environment for marine organisms.

Understanding ocean pH is crucial because it impacts marine life, especially organisms that rely on calcium carbonate for their shells and skeletons, such as corals and some shellfish. When the ocean absorbs atmospheric CO2, it can lower pH levels, leading to ocean acidification, which poses significant risks to the health of ocean ecosystems.

The other pH ranges listed in the options do not accurately reflect the typical state of ocean water. The intervals of 7.4-7.6 and 6.5-7.0 indicate a more acidic environment, which is generally not representative of ocean conditions, while the 9.0-9.5 range suggests an excessively alkaline environment, which is also uncommon in natural ocean settings.