Life in the Arctic Ocean

29 October 2020
Join Dr Libby Logerwell on an expedition into the waters of the Arctic Ocean. Dr Logerwell is a marine biologist at the National Oceanic and Atmospheric Administration (NOAA), Co-Chair of the Ecosystem Approach Expert Group within our Working Group on the Protection of the Arctic Marine Environment (PAME) and one of the experts who joined the Arctic Council’s initiative to enhance marine coordination. Together with her we are exploring the rich life in the Arctic Ocean and the challenges it faces as the habitat changes.

There are two ways to join the expedition: Read your way through Dr Logerwell's interview or watch her recording on the Arctic Council Vimeo channel.

Once we embark on a journey into the Arctic Ocean, what are some of the marine dwellers that we can expect to find in the cold Northern waters?

I work mostly in the Chukchi Sea and I study things that you can catch with a net from a research or fishing vessel. I find that I catch a lot more at the bottom than in the water. And I catch a lot more invertebrates than fish, so things like sea stars, clams, snails of lots of different species, sand dollars, shrimps and crabs. This is important because many of these are prey for marine mammals such as walrus and also for seabirds, such as endangered sea eiders. This is a unique characteristics of Arctic ecosystems, having so much benthic invertebrate biomass (total weight) on the bottom.

Zooplankton. Photographer: Matt Wilson/Jay Clark, NOAA NMFS AFSC. (CC BY 2.0)

How are you able to investigate what lives in the depths of the Arctic Ocean?

I work with a large team of researchers and we study every aspect of the Arctic ecosystem. So, we all go out on boats for many weeks – sometimes for seven weeks at a time. Me and my team, we are deploying nets into the water, both at the bottom and in the water, to catch fish, invertebrates and also zooplankton (small animals), which can be microscopic, shrimp-like creatures like copepods or krill that are prey for many fish and even some marine mammals.

There are other members of our team that study the bottom sediments. So, they use grabs and cores to get samples of the sediments and of the creatures that live in the sediment. I have other colleagues that have instruments to measure water temperature, salinity, pH and catch phytoplankton or algae. These instruments are either cast from the ship and brought back on board, or they are actually put on fixed moorings that stay out all year long and collect data every day.

Other colleagues use their eyes or binoculars or ears to count sea birds and marine mammals out at sea. Because marine mammals emit sounds as they move through the water, acoustic listening devices can pick up a lot of those sounds. Sometimes we can take advantage of data from satellites that show ocean temperature and also color, which is an indication of how much algae growth or primary production is going on.

And finally, we are learning in the Arctic that Indigenous and local knowledge are really important and useful. This is knowledge and understanding that is coming from people that live in the villages around the Arctic. They have lived there for thousands of years and they are there every day. So, we can learn a lot from them when we can’t be there ourselves.

Sea ice, months of complete darkness, cold waters – how do organisms adapt to these conditions?

It’s amazing that as much lives up there as does. I find that fascinating. A couple of things that I can think of is that many of the fish that live there have anti-freeze in their blood and this allows them to survive temperatures below zero. Also a lot of other creatures deal with winter by basically going into hibernation – just like a bear. So, a lot of the zooplankton do what we call diapause; they go down to the bottom and into a resting state and stay there until spring comes, the water waters warm up and they come back into action.

Recovering a CTD (conductivity-temperature-depth) rosette. Credit: Collection of Dr. Pablo Clemente-Colon, Chief Scientist National Ice Center. (CC BY 2.0)

How is the Arctic Ocean changing, and what does that mean for marine organisms?

There’s a lot going on in the Arctic right now and it’s happening really fast. As far as warming water temperatures goes, it is possible that waters can get so warm that some animals’ physiology is not adapted to it any longer. Regarding loss of sea ice, sea ice is very important. It is a source of food, there’s actually phytoplankton or algae in the ice and when the ice melts that algae flows into the water and feeds the food web. And ice is also really important for marine mammals as a surface for resting or having pups.

Ocean acidification is a worry. It is possible that acidification could weaken the shells of benthic clams that are prey for walruses and ducks. Further, noise from shipping vessels could disturb marine mammals and disrupt their feeding behaviour or migrations. Vessel activity could also create noise and disturbance for humans who are subsistence hunters that rely on whales for their food.

And finally, thinking of species that are specially adapted to the Arctic, they might find it harder to survive. In addition, new species may move into the Arctic from the South and we don’t know what the outcome of that interaction will be, this invasion of new species. There’s a lot to learn, a lot of uncertainty.

Why should we care about the Arctic – even if we live much further South?

The Arctic is important, even if it’s not in your backyard. There are a lot of important organisms and a lot of unique human cultures that depend on the Arctic. And the processes that are happening in the Arctic will affect the whole planet. So, I think that we should all turn our eyes to the Arctic and do our best.