As rising global temperatures continue to melt more Arctic sea ice, nitrogen is expected to play a greater role in supporting organisms in regions never thought possible.
What’s going on?
In a recent study published for the first time in the journal Communications Earth & Environment, a team of researchers from the University of Copenhagen took a closer look at nitrogen fixation, a process in which bacteria convert atmospheric nitrogen gas into fuel that can be used to grow algae. They uncovered a remarkable discovery that could have a substantial impact on the planet.
The persistent loss of Arctic sea ice is increasing nitrogen fixation, which can cause algal blooms in the Arctic Ocean. This would not only support the Arctic marine food web, but could also potentially increase the Arctic’s capacity to absorb carbon dioxide. This could ultimately play a positive role in the fight against future global temperature rise.
Why is increased nitrogen fixation important in the Arctic Ocean?
The study was led by Lisa W. von Friesen, a postdoctoral researcher in marine ecology at the University of Copenhagen. She offered valuable insight into her team’s findings and explained why the discovery of nitrogen fixation under melting Arctic sea ice was a surprise.
“Until now, it was believed that nitrogen fixation could not take place under sea ice because it was assumed that the living conditions for organisms that carry out nitrogen fixation were too poor. We were wrong,” said von Friesen in a news release.
As the melting of Arctic sea ice continues, more algal blooms may be produced in the coming years. The non-cyanobacterial diazotrophs that feed on dissolved organic matter produced by these algae can then release fixed nitrogen, especially along the edges of the ice sheets. This can create a symbiotic relationship that has the potential to support an even more robust marine food web.
“In other words, the amount of available nitrogen in the Arctic Ocean has probably been underestimated, both today and for future projections. This may mean that the potential for algae production has also been underestimated as climate change continues to reduce sea ice cover,” added von Friesen.
What is being done about predicting future global conditions?
Despite the potential benefits, the increased rates of nitrogen fixation under melting Arctic sea ice may also create some uncertainty for researchers. Now equipped with a more detailed understanding of nitrogen fixation, climate researchers will likely need to adjust future climate models for more accurate predictions of changing conditions in and around the Arctic.
“For the climate and the environment, this is probably good news. If the production of algae increases, the Arctic Ocean will absorb more CO2 because more CO2 will be bound in the algae biomass,” said Lasse Riemann, professor of biology at the University of Copenhagen and senior author of the study. “But biological systems are very complex, so it’s hard to make firm predictions, because other mechanisms can pull in the opposite direction.”
Currently, rising global temperatures have been linked to more frequent and intense extreme weather events. Warmer temperatures have also led to sea level rise, threatening coastal communities around the world.
“We still don’t know if the net effect will be beneficial for the climate. But it’s clear that we have to include an important process like nitrogen fixation in the equation when we try to predict what will happen to the Arctic Ocean in the coming decades as the sea ice recedes,” added Riemann.
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