Rolf Gradinger – Scientists

Rolf GradingerRolf Gradinger
Associate Professor
School of Fisheries and Ocean Sciences
University of Alaska Fairbanks

What questions related to the Arctic are you trying to answer? I have been working in the Arctic since my first expedition as a graduate student in 1984. Since my first trip, I was fascinated by sea ice. I was amazed to see that sea ice harbors such an abundant flora and fauna. Millions of tiny bacteria, plants and animals live within each square foot of the sea ice, forming the base of an ice-associated food web. The ice algae are the food of amphipods, which are the food of Arctic cod, which again is the main food for Arctic birds and mammals.

I try to improve our understanding of how these organisms have adapted to their ice habitat, why we find them in certain concentrations, and what the contribution of this entire sea ice community is for the food web in different Arctic regions. This requires not only a detailed understanding of the diversity of life in the sea ice but also an understanding of the productivity of the ice regime. I also want to know, which organisms…benefit from the ice-associated biology.

How will answers to those questions help us understand more about our world?

There are several aspects of relevance:

  1. Food for native communities

Native communities in the Arctic rely on marine food (fish, whales, seals) as an important component of their diet. Sea ice is an important part of the life cycle of these species and we try to understand the complexity of interactions relevant for the Arctic ecosystem.

  1. Species diversity

Although sea ice has been studied for more than 100 years, we still do not know how many species occur in this habitat. This might provide important baseline information if we want to follow the expected change in community composition over the next decades. Which species will grow better under a warming climate? Are they ones that have been there before, or will sub-polar species invade certain parts of the Arctic? Are these new species suitable food for animals like fish, birds or mammals? Will we find toxic phytoplankton species in a warming Arctic? There are many questions for which we need reliable baseline information. That is why we started the Arctic Ocean Diversity project, a contribution to the Census of Marine Life (

  1. Potential for new physiological pathways.

Living conditions in sea ice can be extreme – extremely cold (down to –30deg C) and extremely salty (more than five times more than sea water). How can organisms grow under such conditions? Can we use some of these [special] characteristics (e.g. cold adapted enzymes) for producing substances useful for humans and/or commercial applications?

How are you trying to find the answers to those questions? To a large extent, we need to go to the field, take samples, start experiments and follow the natural cycle. Adding it up, I have spent more than a year in the Arctic, collecting ice material and trying to analyze the diversity and activity of the ice communities. Many of these expeditions lasted for several weeks to months. Other trips (like to Barrow) are more on a time scale of a week. The lab analyses include understanding the chemical composition of the ice biota, counting them under a microscope and keeping them alive in a climate controlled chamber.

Recount for us one of your field days in the Arctic. I love being in the Arctic. Each expedition is different, the ice conditions differ from year to year and the weather and climate changes as well. Being on an icebreaker for three weeks with a group of colleagues is exciting, as I can learn more about what they study. I was very excited about the 2005 Ocean Exploration expedition with the US icebreaker Healy into the Beaufort Sea. We had divers studying the under-ice environment; we took ice samples and looked for all different life forms. Here is an excerpt from the log of scientist Katrin Iken, a colleague and experienced under-ice diver:

Most different from regular diving operations, under-ice divers are tethered to the surface. On the surface, a dive tender holds on to the tether and can communicate with the diver via a code of short pulls on the rope. Every diver under the ice always has to be tethered to the surface because it is very hard to keep orientation under the ice. During regular diving, maintaining orientation is not much of a problem because the diver can just come to the surface, re-orient, and continue the dive or surface-swim back to land or the boat. During under-ice diving this is not possible. The sea ice creates a solid lid on the surface and does not allow the diver to come up at any location. Using a tether is the main safety measure during ice diving. (Source: This website has many pictures, logs and videos)

But the most exciting aspect for me in recent times was the [discovery] of a new species. My colleague Bodil Bluhm and I found a small jellyfish related animal in the sea ice, and we sent samples to our Italian colleague Stefano Piraino – it turned out to be a new genus and new species and we are currently working on publishing these results. One first paper has already been published (Bluhm BA, Gradinger R, Piraino S. 2007. First record of sympagic hydroids (Hydrozoa, Cnidaria) in Arctic coastal fast ice. Polar Biology, 30:1557-1563.)

What do you find most rewarding about being a scientist? I believe it is a great privilege to can do the kind of work I do. I interact with wonderful colleagues including very talented students. We are involved in many projects, where I meet people from other disciplines and other research foci – maybe with our involvement in the Census of Marine Life as a highlight of my career. But most of all, I can do what I really enjoy and what I want to do – this gives me all the motivation I need to keep going and stay involved in the scientific world.


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