Algae of the Arctic Ocean and their importance for the food web

Today was cloudy, which we were not used to , and we are heading for the eastern side of Banks Island, in the Amundsen Gulf. Since my arrival on the ship, we have traveled hundreds of nautical miles, starting at Cape Perry and going as far as Mclure Strait, north of Banks Island. The main objective for our team is to measure the primary production of the Arctic Ocean. But why is this so important?

A lot of Inuit communities are depending on the ocean either for food, health or work. Global warming might have a great impact on the Arctic ecosystem, which may alter their lifestyle and well-being. The algae, which are microorganisms, are the most important ones in the ocean. They are the beginning of the food web, which means that the bigger organisms, like copepods and other zooplankton species, are feeding on algae.

The primary production of the algae is quite important, but sometimes difficult to quantify. With the rosette (fig. 1, left & right), we are collecting water at different optical depths (light intensity at different depths) measured with a natural light profiler.

Fig. 1: The rosette with CTD (Conductivity, temperature, depth) sensors

After getting the water, we add a radioactive tracer (Carbon 14) to measure the carbon uptake rate of the algae. We incubate the algae in situ for 24 hours (fig. 2) in approximately the same environmental conditions of light and temperature. To control the light intensity, we add filters on different plexiglass tubes and we measure the light inside of them.

Fig. 2: The incubator on the foredeck of the Amundsen

Then, we go back into the lab where we filter the samples in a green environment. Why’s that? Because the algae contain different pigments able to absorb different light wavelengths. However, the green is reflected by the algae, which explains their greenish color (Fig. 3).



With the radioactive products, we have to be careful and safe and we need to wear gloves and a lab coat. When the filtration is done, we analyze our samples by counting the amount of carbon 14 in each sample to determine the production rate.

With global warming affecting mostly the polar regions, this study will help our understanding of the impacts of these climate changes on the Arctic Ocean ecosystem. After starting my masters at the University of Québec at Rimouski one year ago, I can say that I have learned and am still learning a lot about the Arctic and its fragile environment. Every person should be involved in protecting our environment, which is full of many challenges, from 100 years ago into the future.