As rising global temperatures continue to melt Arctic sea ice, nitrogen is expected to play a larger role in supporting organisms in areas where it was never possible.
what’s going on
In a recent study first published in the journal Communications Earth and 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 usable fuel for algae growth. They made a remarkable discovery that could have a substantial impact on the planet.
Continued loss of Arctic sea ice is increasing nitrogen fixation, which can trigger algae blooms in the Arctic Ocean. Not only will this support the Arctic marine food web, but it could potentially increase the Arctic’s ability to absorb carbon dioxide. It can ultimately play a positive role in combating global warming in the future.
Why is the increase in 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 provided valuable insight into her team’s findings and explained why the discovery of nitrogen fixation under melting Arctic sea ice came as a surprise.
“Until now, it was believed that nitrogen fixation could not occur under sea ice because it was assumed that living conditions were too poor for nitrogen-fixing organisms. We were wrong,” von Friesen said in a news release.
As Arctic sea ice continues to melt, more algal blooms may be produced in the coming years. Non-cyanobacterial diazotrophs feeding on the dissolved organic matter produced by these algae can release certain nitrogen, particularly at the edges of ice sheets. This can create a symbiotic relationship that has the potential to support a stronger seafood web.
“In other words, the amount of available nitrogen in the Arctic Ocean is underestimated today and for future projections. This may mean that the potential for algal production is also underestimated as climate change continues to reduce sea ice cover,” von Friesen added.
What about predicting future global conditions?
Despite the potential benefits, the increased rate 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 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 algae production increases, the Arctic Ocean will absorb more CO2 because more CO2 will be bound in 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 are associated with more frequent and intense extreme weather events. Warmer temperatures have caused sea levels to rise, threatening coastal communities around the world.
“We don’t yet know if the net effect will be beneficial for the climate. But it’s clear that we need to include an important process like nitrogen fixation in the equation when we try to predict what will happen as sea ice declines in the Arctic Ocean in the coming decades,” Riemann added.
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