Radio Script
2002

Above water level, the ice surface is seen as an expansive white plane. Under the water, the scene is very different. (Courtesy NOAA Ocean Exploration.)

Life in Ice
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INTRO: For much of the past month, scientists have been exploring the sea beneath the Arctic Ocean ice pack. But as Doug Schneider reports in this week's Arctic Science Journeys Radio, the animals and plants that live within the ice itself are what most interest one scientist.

STORY: A team of American, Japanese, Canadian and Chinese scientists are now in the ice-covered Arctic Ocean, aboard a Canadian icebreaker. They're among the first to use high-tech remotely operated vehicles and digital cameras to explore the depths beneath the vast sheet of ice that covers the region. But one scientist is more interested in what lives inside the ice. Rolf Gradinger is a marine scientist at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. He says entire communities of animals and plants thrive in the tiny spaces between the ice crystals.

GRADINGER: "At first view, you might consider that hardly anything could live in ice. But sea ice is very special because of the salt in the ocean. When seawater freezes, there's no life in the ice crystals themselves. But between the ice crystals you have a high-salt solution called brine. And ten to thirty percent of the entire volume of the ice is filled with this solution, and this is the space where creatures live. You find bacteria, unicellular algae and even small animals. The largest ones, the giants living within the ice, are about the size of a millimeter."

Gradinger says hundreds of single-celled plant species, such as diatoms and other algae, live in the salty solution between individual ice crystals. Somehow the plants are able to carry on photosynthesis, even though they receive only about ten percent of the sunlight that reaches the ice surface.

Two divers explore the unique habitat beneath the Arctic Ocean ice pack. (Courtesy NOAA Ocean Exploration.)

GRADINGER: "The ice cover itself takes away a huge amount of light. So light availability is much lower where you have ice cover than in sea waters that are not covered by sea ice. Secondly, the availability of nutrients, of fertilizers for the plant to grow, is reduced within sea ice. But surprisingly, a lot of algae species have adapted to these conditions. Some even can't grow if you give them too much light."

In fact, Gradinger says these ice-bound plants are able to absorb enough sunlight to account for as much as a quarter of all the plant growth each spring and summer in the Arctic Ocean. The algae growth turns the underside of the ice pack into a lush pasture that's grazed by a surprising array of animals, including amphipod crustaceans and flatworms. Gradinger says fish like the Arctic cod ultimately owe their existence to the plants living among the ice crystals.

Small amphipods like this are the link between primary production in the ice and the fish species. (Courtesy NOAA Ocean Exploration.)

GRADINGER: "The link between primary production in the ice and the fish species are small amphipods. These are small crustaceans about the size of a centimeter up to five centimeters. They live on the underside of the ice and occur in abundance from ten to more than one thousand specimens per square meter."

Gradinger uses special cameras and even sends scuba divers under the ice to see firsthand how life is able to flourish beneath a layer of sun-blocking ice. But he says much still remains unknown about these hidden communities.

A diver emerges from a dive under the Arctic pack ice. Diving under the ice follows strict safety procedures and is done only by experienced divers. (Courtesy NOAA Ocean Exploration.)

GRADINGER: "The role of the sea ice communities is not well understood. This is one of the reasons why we have the opportunity to do this type of research during this Arctic exploration. It really is exploration. What we are doing is sampling different parts of the ice floes, from the surface, the bottom, in pressure ridges, and all different habitats. And we are looking into what kind of animals and plants live in these niches, and we try to get a handle on how active they are."

OUTRO: This expedition to the Arctic Ocean is funded by the National Oceanic and Atmospheric Administration's Ocean Exploration program. This is Arctic Science Journeys Radio, a production of the Alaska Sea Grant Program at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences. I'm Doug Schneider.

Thanks to the following individual for help preparing this script:

Rolf Gradinger, Assistant Professor
University of Alaska Fairbanks
School of Fisheries and Ocean Sciences
Institute of Marine Science
Fairbanks, AK 99775-7220
Email: rgradinger@ims.uaf.edu
Phone (907) 474-7407

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Related Web sites

NOAA Ocean Exploration: Canadian Basin Exploration

NOAA Ocean Explorer: Sea Ice Communities

NOAA Ocean Explorer Home Page

University of Alaska Fairbanks School of Fisheries and Ocean Sciences

Rolf Gradinger faculty profile

ASJ Hidden Ocean