By Magda Cardozo |
The Fram Strait the major gateway between the Arctic and the Atlantic Ocean and is located in the Marginal Ice Zone. This means that during summer, Arctic sea ice travels southwards through the Strait. This makes the Fram Strait a rather unique area. However, our understanding of the Arctic Ocean is currently restricted to the summer season because active cruise work and sampling has largely only been possible during the summer months. The physical and chemical characteristics of the Arctic sea ice have been studied extensively, yet, the knowledge of microbes in the ice and their interaction with the sea water community that surrounds them is still sparse. This year, we visited the ice in the Marginal Ice Zone, and we collected samples of ice to conduct an experiment on board to answer some of these questions.
Visiting the ice in the Arctic Ocean requires some preparation and depends largely on the weather conditions. On a calm weather day, we flew by helicopter and landed on an ice floe big enough to land and to set our base camp. We explored the conditions of the ice by extracting different ice cores from different areas until we decided on a suitable floe for ice sampling. We worked, and at the same time, we enjoyed every minute of it. Like any ice-covered region on earth, the sunlight that reflects off of the ice can be harmful, so we had to wear sunglasses and sunscreen lotion to protect from UV rays. We observed the beauty of the white ice and the shades of blue frozen water ponds underneath. We could hear the sound of the cracking ice far in the distance, and this reminded us how in civilization, we are constantly surrounded by all sorts of anthropogenic noises that we forget the beauty of nature. The absence of sound is something I thought I would never experience so deeply. While sampling, we were constantly visited by Arctic birds that surveyed us from above to see what we were doing in their ecosystem. We said goodbye to the ice after three hours of hard work and headed back to RV Polarstern. During the flight back, we spotted a fin whale swimming beneath us in all its majesty, as if it was waving us goodbye.
Back on board of RV Polarstern, I performed an experiment in which I submitted the ice cores to melting in sea water at 1 -2 °C and collected samples every few hours until the ice was completely melted. These samples will be further analyzed back in Germany for bacterial DNA and other parameters that aim to address the connectivity between bacterial communities in sea ice and the surrounding water during ice melt. With every summer, we face new minimum ice records in the Arctic sea ice coverage due to climate change and ocean warming, and these samples are fundamental for us to understand what is occurring with the microbes in the Arctic sea ice, and how anthropogenic activities are affecting the Arctic ecosystem.
By Magda Cardozo, PhD student of Max Planck Institute for Marine Microbiology, Bremen