The world’s oceans are home to some of the most profound ecological processes on Earth.
The world is home to more than 30 billion species of marine life.
The oceans, and the creatures that inhabit them, are a key focus of research, conservation and political discourse.
But what exactly is the role of the ocean?
How are we seeing the impacts of climate change on the oceans?
Al Jazeera’s Heather Halsey reports from Sydney.