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Where do microscopic ice organisms go after Arctic's annual melt?

  • Author: Hannah Heimbuch
  • Updated: September 27, 2016
  • Published May 14, 2012

Many people who live in the Lower 48 aren't familiar with the Arctic's long growing season. The region's reputation for darkness and cold usually dominates Outsiders' perception of the northernmost climate.

But under those sprawling floes, packed into the heart of the sea ice environment, a world of phytoplankton curls its fate round the sun — as much as any California tomato or Florida orange. Frozen though it may be, sea ice is not stagnant.

"There is a whole community of organisms that live inside of the sea ice. That includes a lot of microscopic algae," said Columbia University microbiologist Andrew Juhl.

Sea-ice core samples

This summer, Juhl is leading a team based out of Barrow, which will spend a month taking sea-ice core samples and studying its plant-matter contents, starting at the end of May.

Organic matter starts its rapid bloom almost as soon as the sun returns to the Arctic. It spends the spring expanding and growing, looking like a layer of brown ice stretched along the bottom of the ice pack.

In mid-to-late May, the annual melt releases that matter. What Juhl and his team will be studying is what happens next. Where does that matter go? What eats it? And how is it connected to the larger ecosystem?

Once the matter is released into the water column, its fate depends on how fast it sinks, Juhl said. That determines what kind of larger organism will feed on the ice-bred phytoplankton, bottom dwellers or mid-ocean inhabitants.

By studying the matter found in the ice core samples, Juhl and his colleagues establish a DNA fingerprint for the unique algae. They can then identify that fingerprint in other locales — gut contents of Arctic fishes, bottom samples, and so on. They can also bring that matter back to their lab at Columbia and test its sinking rates.

It's important to know where this matter ends up, Juhl said. "(There are) a whole lot of organisms near the base of the food chain that have their life cycles timed to take advantage of this boom. (They are) one of the reasons that the Arctic is so productive."

Scientists descend on Barrow

Up to 20 percent of all Arctic marine plant productivity happens inside of the sea ice every year, Juhl said, making this tiny ecosystem a bigger player than the naked eye can take in.

This is Juhl's fifth research trip to Barrow, and along with his scientific team he is bringing a New York high school science teacher, Fran Hess.

One goal of the study, originating with Columbia's Earth Institute, is to produce educational materials available online.

A number of other Earth Institute studies will taking place in Alaska later in the summer, including ecologist Natalie Boelman's climate change study of plants, insects, birds, caribou and peat. That project, a five-year study, will take place in June and July, based out of Toolik Lake.

Paleoecologists Dorothy Peteet and Jon Nichols will conduct a study in early July, pulling up ancient tundra peat to study carbon storage and seek clues to past climate changes.

More on these projects and others done under the auspices of the Earth Institute can be found here.

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