Posted on June, 05 2017

A new paper suggests that the Arctic's rapidly disappearing older ice plays a larger role in Arctic ecology than previously thought. 
 
While an increasing percentage of Arctic sea ice melts each summer, a portion of the Arctic Ocean remains covered in ice year-round. New research on ice cores sampled from this multi-year ice show thriving communities of algae - tiny plants that form the basis of the Arctic food web.

Watch: Decline in multi-year sea ice

 
Because algae depends on sunlight, the underside of thick ice has not previously been considered important algal habitat. However, snow-free areas called hummocks frequently form on older ice, and these permit much more light to pass through to the water below.
 
According to the study's authors, "...our results indicate the loss of [multi-year ice] will also mean the loss of reliable ice-algal habitat during spring when food is sparse and many organisms depend on ice-algae."
 
The Arctic's sea ice is becoming younger and thinner each decade. Nearly all of the  remaining multi-year ice is found in the "Last Ice Area" - the northern coasts of Greenland and Canada, where sea ice is projected to last the longest. 
 
Read Pan-Arctic sea ice-algal chl a biomass and suitable habitat are largely underestimated for multiyear ice