Research shows that shrinking sea ice has caused Arctic phytoplankton to bloom an average of 50 days earlier than 14 years ago.
Climate researchers have long warned that the Artic is particularly vulnerable to global warning. A new report finds that the disappearing ice has apparently triggered another dramatic event – one that could disrupt the entire ecosystem of fish, shellfish, birds and marine mammals that thrive in the harsh northern climate.
An oceanographer at the Scripps Institution of Oceanography in San Diego, Mati Kahru and his international team has studied worldwide phytoplankton blooms from 1997 through 2009. He states that the ice is retreating earlier in the Arctic and the phytoplankton blooms are also starting earlier. Observations from three American and European climate satellites can spot the blooms by their color, as billions of the tiny organisms turn huge swaths of the ocean green for a week or two.
In 11% of the areas where Kahru’s team was able to collect good data the blooms peaked earlier and earlier. Kahru has said that the impacted zone covers roughly 1 million square kilometers including portions of the Foxe basin and the Baffin sea, which belong to Canada, and the Kara Sea north of Russia.
The study shows that in the late 1990’s, phytoplankton blooms in these areas hit their peak in September, only after a summer’s worth of relative warmth had melted the edges of the polar ice cap. But by 2009 the blooms’ peak had shifted to early July.
“The trend is obvious and significant, and in my mind there is no doubt it is related to the retreat of the ice” said Kahru, who published the work in the journal Global Change Biology.
As the phytoplankton bloom explosion is timed into the reproductive cycles of many animals, the earlier blooming time can have cascading effects up the food web all the way to marine mammals. The Artic food web is poorly studied, so resulting decline in fish, seabirds and mammals is difficult to quantify. Other research has shown that in the northern Atlantic the cod population falls when plankton blooms early in that region.
Abstract from the article “A Changing Arctic Ecosystem Raises Concerns About Sustainability” by Brian Vastag in the Washington Post on March 7, 2011
[Information received from Paul Vesterstein, a relative of Mati Kahru]
