Beneath Arctic ice, life blooms spectacularly

Oceanus - 

Scientists have discovered a massive bloom of phytoplankton beneath ice-covered Arctic waters.

Until now, sea ice was thought to block sunlight and limit the growth of microscopic marine plants living under the ice.

The amount of phytoplankton growing in this under-ice bloom was four times greater than the amount found in neighboring ice-free waters.

The bloom extended laterally more than 100 kilometers (62 miles) underneath the ice pack, where ocean and ice physics combined to create a phenomenon that scientists had never seen before.

Reporting in the June 8, 2012 edition of the journal Science, a multi-institutional team of scientists concluded that ice melting in summer forms pools of water that act like transient skylights and magnifying lenses.

These pools focused sunlight through the ice and into waters above the continental shelf north of Alaska, where currents steer nutrient-rich deep waters up toward the surface.

Phytoplankton under the ice were primed to take advantage of this narrow window of light and nutrients.

“Way more production is happening under the ice than we previously thought, in a manner that’s very different than we expected,” said Sam Laney, a biologist from Woods Hole Oceanographic Institution (WHOI).

Just as a rainstorm in the desert can cause the landscape to explode with wildflowers, this research shows that events like pooling melt water can happen on very short timescales in the Arctic yet have major effects on the ecosystem.

“If you don’t catch these ephemeral events, you’re missing a big part of the picture.” Laney was part of the team that made the unexpected discovery on a 2011 expedition led by chief scientist Kevin Arrigo of Stanford University aboard the U.S. Coast Guard icebreaker Healy.

It was part of the NASA-funded ICESCAPE program to investigate the impact of climate change in the polar Chukchi and Beaufort seas.

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