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Algae Blooms in Antarctic Waters: Earth Image of the Week March 23, 2012
Satellite Image of Antarctic algae bloom.
Swirls of green ice are visible in this image from NASA's Terra satellite, taken on February 27, 2012.
NASA satellite image analysts were puzzled by a pale green tint that appeared during late February in the sea ice off the coast of East Antarctica.

And since there was no immediate way to place “eyes on the ground” in the extremely remote region, NASA enlisted several experts around the world to help determine what was causing the green color.

Oscar Schofield, a biological oceanographer at Rutgers University, had his own long-distance interpretation: “From the imagery I have seen, it does look like an ice edge bloom, though it is unlikely we can say what species. Ice edge blooms are not unusual there, though it is late in the season.”

Researchers at the Antarctic Climate and Ecosystems Cooperative Research Center previously examined the MODIS image and declared on their web site: “Wind blowing snow off the Amery Ice Shelf in East Antarctica appears to have released nutrients which have triggered a massive algal bloom (believed to be phaeocystis).”

Jan Lieser, a scientist with that Australian research group, added by email: “I witnessed this bloom in East Antarctica at about the same time. The largest single patch was in the Cape Darnley region, between the Amery Ice Shelf and Mawson Station. I have also seen smaller blooms to the west of the West Ice Shelf and off the Mertz Glacier region in recent weeks. Blooms are not unusual in Antarctica and have been reported before, but usually at a different time of year (early December).”

But the final word came from Lieser’s colleagues, who were able to redirect the Australian research vessel Aurora Australis to take a few surface water samples of the bloom en route from Antarctica’s Mawson Station to Hobart, Tasmania: “Reports from the ship as it was sampling and traversing through the bloom indicate that the region was covered by small pancakes of sea ice with algae visible on the sides and undersides, apparently floating in a sea of greenish brown.”

Samples of the algae will be further analyzed when they arrive in Hobart in late March.

Full story and image: NASA