
Planet Ocean is a 2013 documentary which attempts — and largely succeeds — to provide a glimpse at the many ways, both large and small, that the oceans drive populations and processes all across our planet. With roughly 70% of our planet covered in water, it stands to reason that the oceans would have a dramatic influence on the ways in which our planet operates. One of the most important but largely invisible ways the oceans influence our world is through their role in the carbon cycle.
It’s estimated that there are about 38,000 gigatons of carbon sequestered in the world’s ocean. For comparison, we release only about 42.2 gigatons per year globally. That’s only about a tenth of one percent of what the oceans are holding. That process, however, has occurred over millions of years and recent human activities have thrown it all out of whack. Suddenly, on a planetary scale, we’re dumping way more carbon than the oceans can quickly soak up.
The oceans store carbon in two primary ways. The first is through chemical processes in which gaseous CO2 essentially carbonates the oceans, though at nowhere near the same level as a can of soda. This process also makes the water more acidic, something which is a particular concern as climate change progresses. Most fish don’t like swimming in increasingly acidic waters, and we don’t blame them. The second way is through carbonate sediments which gather on the seafloor over long stretches of time. In order for that to happen, CO2 has to be converted to bicarbonate ions through interactions between rainwater and certain rocks.
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Cassidy Ward, SYFY, 3 October 2022. Full article.