Episode 1 – The Living Breathing Ocean

Marine Snow

By Nicola Temple, Australian Marine Conservation Society.
Life on this planet is completely dependent on the oceans, and it is in the oceans that most life on this planet exists. It is the oceans that drive our weather patterns and climate, produce at least half of the oxygen we breathe, and absorb the carbon dioxide we pump into our atmosphere. Roughly one third of the atmospheric carbon dioxide that humans produce is absorbed into the ocean.

A portion of this carbon is captured by organisms that integrate it into their tissues. Reef-building corals are the best example of this, producing calcium carbonate structures that can be seen from space. Other organisms, like plankton, integrate carbon into their tissues, skeletons and shells and when they die, they fall down to the ocean floor as marine snow, sometimes taking weeks to reach the bottom. It is through this basic process that our oceans act as a net sink for carbon dioxide, locking the carbon into the organic sediments of the ocean floor.

Some of this carbon will dissolve over time and be cycled up into shallower waters through ocean currents where they will be reabsorbed by other organisms, however, some will remain locked up in the sediments deep on the ocean floor.

The chemistry of our oceans is interlinked with the chemistry of our atmosphere. As we continue to increase carbon emissions, we are changing the chemistry of our oceans, thereby altering our planet as we have known it.