Posted on 10/24/2025 12:29:54 PM PDT by Red Badger
Measurements were taken at 13 different locations in the Arctic Ocean. Credit: Lisa W. von Friesen
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As Arctic sea ice melts, new life may emerge from the thaw. Researchers have discovered that bacteria beneath and along the melting ice are converting nitrogen gas into a form that fuels algae.
The rapid loss of Arctic sea ice is widely seen as a catastrophe. Yet, in an unexpected twist, the melting ice may actually boost the foundation of Arctic marine ecosystems: algae.
Algae serve as the essential food source for most ocean life, but their growth depends on nitrogen, a nutrient that is scarce in the Arctic’s frigid waters. Now, a new international study led by the University of Copenhagen suggests that future levels of nitrogen in the Arctic Ocean may be higher than previously estimated. This finding could have major implications for marine ecosystems in the High North and for the global carbon balance.
For the first time, scientists have identified nitrogen fixation occurring beneath the Arctic’s sea ice, even in its most central regions. This process involves certain bacteria that transform nitrogen gas (N2) dissolved in seawater into ammonium. The ammonium supports bacterial growth while also nourishing algae and the many organisms that depend on them throughout the marine food web.
Measurements of Nitrogen Fixation Arctic
“Until now, it was believed that nitrogen fixation could not take place under the sea ice because it was assumed that the living conditions for the organisms that perform nitrogen fixation were too poor. We were wrong,” says Lisa W. von Friesen, lead author of the study and former PhD student at the Department of Biology.
Less ice could mean more algae Whereas in most other oceans it is cyanobacteria that perform nitrogen fixation, the study shows that in the Central Arctic Ocean, it is a completely different type of bacteria that converts nitrogen: the so-called non-cyanobacteria.
The researchers have measured the highest rates of nitrogen fixation at the ice edge, where the ice melts most actively. Although the bacteria can perform nitrogen fixation under the ice, it is easier for them to do so along the ice edge. So as the sea ice retreats and the area of melting expands, larger amounts of nitrogen are expected to be added through nitrogen fixation.
“In other words, the amount of available nitrogen in the Arctic Ocean has likely been underestimated, both today and for future projections. This could mean that the potential for algae production has also been underestimated as climate change continues to reduce the sea ice cover,” says Lisa W. von Friesen.
“Because algae are the primary food source for small animals such as planktonic crustaceans, which in turn are eaten by small fish, more algae can end up affecting the entire food chain,” adds Lisa W. von Friesen.
May affect the ocean’s CO2 uptake In addition, the newly discovered source of nitrogen could also be beneficial for the uptake of CO2 – at least regionally. More algae make the ocean better at absorbing CO2.
“For the climate and the environment, this is likely good news. If algae production increases, the Arctic Ocean will absorb more CO2 because more CO2 will be bound in algae biomass. But biological systems are very complex, so it is hard to make firm predictions, because other mechanisms may pull in the opposite direction,” says Lasse Riemann, professor at the Department of Biology and senior author of the study.
Nevertheless, the researchers believe that nitrogen fixation should be included in forecasts for the Arctic Ocean.
“We do not yet know whether the net effect will be beneficial for the climate. But it is clear that we should include an important process such as nitrogen fixation in the equation when we try to predict what will happen to the Arctic Ocean in the coming decades as sea ice declines,” says Lasse Riemann.
Reference:
“Nitrogen fixation under declining Arctic sea ice”
by Lisa W. von Friesen, Hanna Farnelid, Wilken-Jon von Appen, Mar Benavides, Olivier Grosso, Christien P. Laber, Johanna Schüttler, Marcus Sundbom, Sinhué Torres-Valdés, Stefan Bertilsson, Ilka Peeken, Pauline Snoeijs-Leijonmalm and Lasse Riemann, 20 October 2025, Communications Earth & Environment.
DOI: 10.1038/s43247-025-02782-4
If they get too much Algae they can post pictures of Greta around the overgrowth to kill it.
Whoever these brilliant scientists are, they didn’t discover jack.
N2- nitrites- nitrates- ammonium <— that cycle and the organisms that drive it have been known for years.
Anyone who understands aquaponics knows it real well.
#trust the science my @$$.
The maximum Arctic summer ice melt has been smaller - last three years in a row.
In other words, in spite of alleged global warming, we had more Northern Hemisphere ice, three years in a row.
Perhaps the article us above your paygrade?
More lies from “science” about life “springing forth”.🙀
We were wrong....
About so many things
I think that the trend is less melt/more accumulation since 2012.
We best be CAREFUL. If we PUSH the Earth's inborn natural NATURE to SURVIVE to EXTREMES then the Earth is liable to retaliate by SHAKING US OFF like a bad case of fleas.
To put it SIMPLY... "Don't SCREW with Mother Nature" because she is UNCONTROLLABLE.. and can be MERCILESS!
This article begins with the lie that Arctic Ocean sea ice is declining. It is not. Ice coverage varies widely. Some years ago eco freaks were lamenting the sea ice was almost gone. The next year, there was near record ice coverage.
doubt that. Undergrad in marine physiology for Marine Science.
“doubt that. Undergrad in marine physiology for Marine Science.”
Then, read the article ...
FWIW I was writing to this cycle: Ammonium to nitrite (nirosomonas bacteria)) -> Nitrite to nitrate (Nitrobacter) -> plant food.
WRT aquaponics, this is accomplished in an extant tank, or in media beds.
Diazotrophs that fix N2 have been known to science for some time.
That’s what I was harrumphing about.
LAst point and I’ll let it go. “We” have known about the cyanobacter that fix N2 in warmer marine environments for a long time.
Scientists started to understand diazotrophs in the 60s, and in the 70s when I was in school “we” were just beginning to dive deep into the chemistry of their metabolism.
HEre’s a decent paper from 2011 on the topic, if you care. https://website.whoi.edu/gfd/wp-content/uploads/sites/14/2018/10/Sohm_et_al_2011_Nat_Rev_Microbiol_262065.pdf
Diazotrophs that fix N2 have been known to science for some time.”
That is in the article referring to cyanobacteria.
But these are NOT cyanobacteria.
Looks like the article is above your paygrade.
What do you think I got wrong? I read the article.
I’m always willing to learn if I got something wrong.
See my #16.
See my #14 re diazotrophs.
Let it go.
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