The inhaling and exhaling of the northern deciduous forests can be traced in historical carbon records, and the carbon impacts of tearing down the equatorial rainforests are well established. But a third, massive natural carbon sink has not been nearly as well studied as these other two—and some scientists fear its future is in question.

The Southern Ocean—a loosely defined body of water around Antarctica and below Australia—plays a massive role in collecting atmospheric carbon. Its rough seas churn tiny bubbles of air down into the water, trapping a good portion of these bubbles in deep transoceanic currents. The ocean also supports a sizable population of phytoplankton, tiny carbon-dioxide breathing animals that drift to the ocean floor as they die, trapping their carbon footprint down there with them.

But due to a lack of research in the region, scientists are unaware what impacts warming temperatures and other environmental changes will have on this invaluable carbon-catching resource. If warmer temps bring calmer seas and decrease phytoplankton counts, it could create a devastating positive feedback cycle, with warming caused by carbon leading to the release of more carbon.