For life in the oceans to flourish, microscopic plants called phytoplankton - the lowest rung on the food chain - need nutrients to thrive. The world's rivers normally carry this material out into the oceans. But Antarctica has no rivers. Don't worry though, it's got another trick up its freezy sleeve to seed the ocean with nutrients: icebergs.
According to new research published this week in the journal Science, icebergs carry a tremendous amount of terrestrial material - dust, pollen, and other nutrients for microscopic organisms. As the iceberg melts in the southern oceans, it releases its nutritional cargo to a hungry ecosystem.
The phytoplankton start the food chain, working with the nutrients and the Sun. Krill and shrimp eat the tiny plants, and in turn become food for larger and larger animals, right up to whales.
Satellite photos and local sampling have shown that these chunks of floating ice are surrounded by a halo of life, extending out for many kilometers. Scientists counted up more than a thousand icebergs in just Antarctica's Weddell Sea. They estimate that 40% of the region is covered by one of these halos, boosting the biological productivity.
Scientists studied two icebergs in detail, getting as close as 100
meters (300 feet) from the chunks of ice. This is dangerous work, considering that an iceberg can shed huge chunks or just turn over without notice. They worked out to a distance of 9 km (5.6 miles) at which point the influence of the iceberg was no longer detectable.
And here's an added benefit. These regions may soak up a tremendous amount of carbon dioxide. Microscopic plants are eaten by krill, and then the carbon-rich waste (use your imagination here), sinks down to the bottom of the ocean; out of sight, out of mind, out of the atmosphere.
