Newly Freed Iceberg Could Still Waters Threatening Oxygen Levels Necessary to Support Underwater Life
What would happen if the ocean’s currents stopped flowing? If we’re lucky, that question will only be answered by Hollywood script writers or best-selling novelists. But what if we’re not? And what could cause such a thing anyway?
On February 12th or 13th, 2010, the B9B iceberg, which broke free in 1987, dislodged another monstrous iceberg from the Mertz Glacier Tongue. The newly freed iceberg covers 985 square miles and is 1300 feet thick. Now the two icebergs are drifting around the Southern Ocean and are expected to do so for many years.
The Southern Ocean is home to the Mertz Glacier Polynya. Polynyas, warm areas of water surrounded by ice, are responsible for the production of sea ice and the generation of ocean currents. When salt water freezes, much of the salt is left behind and a heavy brine forms and sinks to the bottom of the ocean. This dense water then flows from the Southern Ocean, carrying heat, nutrients, and gases including oxygen throughout the ocean basins of the world.
Unfortunately, if these thick icebergs drift over the Mertz Glacier Polynya, the production of sea ice and the dense brine water will cease, slowing the ocean currents, and preventing the nutrients and oxygen necessary to support life from flowing. While scientists are unsure if the iceberg broke away because of global warming, they can’t rule it out. According to Glaciologist Benoit Legresy, "obviously when there is warmer water, these ice tongues will become more fragile."