The microbial shift that has the potential to permanently alter the Arctic

The microbial change that could change the Arctic forever

Small microorganisms in the Arctic react to the warming climate - and this could have consequences for life all over the world.

microbial change that could change the Arctic forever

Martin Nielsen reaches over the side deck of the Porsild and grabs the 100-meter long bongo net that is pulled out of the arctic water. He is supported in this by the crew member Eli Martensen, an Inuit fisherman who is regularly on these monthly trips.

The net is designed to capture some of the ocean's smallest organisms: zooplankton. After it has been pulled on board, molecular biologist Nielsen - the current scientific director of the Arctic station on Disko Island off the west coast of Greenland - transfers the catch into a sample container and holds it up. Countless transparent, cancerous animals float in the water like in a snow globe.

“When you talk about microorganisms in the ocean, you have to realize that there are so many of them,” explains Nielsen. "[They] are an important part of the food chain."

Besides bacteria and viruses, zooplankton (animals) and phytoplankton (plants) are the most common living things in the ocean. They are a primary source of food for fish and marine mammals, including large whales such as humpback whales and northern right whales. 

In a single day, these giants can eat almost a thousand kilograms of krill, a type of zooplankton, and small fish like capelin that feed on it.

For years scientists have been collecting samples of microorganisms in Disko Bay off the coast of West Greenland and studying them. “The Arctic station has been here for more than 100 years,” explains Martin. "When doing science, it is really important to have access to such long continuous measurements."

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Researchers here have been carefully logging data on everything from soil composition to cloud cover to climate since 1906. 

And while scientists are careful to draw conclusions from these data, two things are certain: the Arctic is warming faster than any other place in the world, and its ecology is undergoing major changes in extremely short periods of time.

Back at the Arctic station, Nielsen looks through a microscope at a Petri dish with copepods. These tiny crustaceans make up most of the pelagic zooplankton. 

A group of icebergs can be seen through the window. The whales usually gather here to forage during the summer, but they haven't appeared this year, suggesting that the capelin they eat are also absent. “We're seeing a change in population dynamics,” says Martin. "A shift in the existing and dominant species."

Much of it has to do with the changing climate. "Phytoplankton and zooplankton are very dependent on climate ... so up here we can see that the amount of Arctic ice is really important to these small communities."

According to Nielsen, some types of phytoplankton and zooplankton can thrive in the changing conditions while others disappear. This creates a chain reaction for living things whose nutrition depends on them, from fish to whales to humans. 

Current research in the Fram Strait between East Greenland and the Norwegian Svalbard Archipelago suggests that as the ice melts accelerated, nutrient-rich ice-dwelling algae can be replaced by phytoplankton that thrives in open water in the summer months. 

The latter has lower fat content than their ice-bound relatives, which are more nutritious for krill and fish, on which the whales depend. "Everything is just too unstable and difficult to predict," says Martin.

Birgitte Danielsen is a geographer who specializes in soil science and climate change. She is also Martin's friend. “I moved to the Arctic to begin field research for my Ph.D. on subterranean gas dynamics in the Arctic,” she explains. 

This fieldwork involves a 45-minute hike to a location on the tundra just below a glacier. Here it carefully records CO2 and methane levels at various depths. "We want to investigate how these extreme winter warming events affect the soil and the microorganisms and how much carbon they will release into the atmosphere as CO2."

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As with marine microorganisms, it is difficult to draw firm conclusions from these data. However, it is entirely possible that warming creates a feedback loop that increases microbial activity in the soil and increases greenhouse gas emissions. “I think that the microorganisms in the soil could be the most numerous on the planet after the microorganisms in the sea,” says Birgitte. "And you can see that the temperature has a big impact here."

What all this means for Greenland and the Arctic is still unclear. But in such an extreme environment, on the frontline of climate change, the unpredictability is very worrying. "The data and scientific research show that the amount of sea ice is decreasing and becoming unstable, and we hear the same thing from the locals who actually use the sea ice on a daily basis," says Martin.

Greenland's ice sheet is the second largest in the world after Antarctica. The island is currently the largest contributor to global sea-level rise and lost 3.8 trillion tons of ice between 1992 and 2018, according to a study by NASA and the European Space Agency. Researchers estimate that by 2100 the sea level will rise by 8 to 13 cm due to the waning Greenland Ice Sheet alone, which will affect 100 million people annually by flooding.

Birgitte and Martin have been on Disco Island for more than a year, where the sun barely rises above the horizon in winter and hardly sets in summer. 

Their bungalow near the laboratories and research facilities of the Arctic station is a small oasis full of plants that they brought back from Denmark. But staying here has made them aware of the environmental impact of their own behavior.

“Through our life here we have recognized that our daily habits actually have an impact on [the] climate,” says Birgitte.

“So we try to live sustainably. We try to save energy whenever we can, ”continues Martin. These include turning off lights, reusing and recycling when possible, composting organic waste, and washing clothes in shorter washes at lower temperatures.

Martin looks out of the window at an ocean full of microorganisms, the basis of the sea's food chain. "Little things are really important," he muses. “The climate is warming up. That is a fact and we must do something about it. "

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In Europe, on average, up to 60% of greenhouse gas emissions caused by washing cycles come from heating water in washing machines - more than from packaging or ingredients. If you lower the temperature by just a few degrees, you can drastically reduce energy consumption.

Photos Credit: National Geographic
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