Nitrogen is necessary for all life on Earth, but like many things, its possible to have too much of it.
For most of the Earth’s history, there was a careful nitrogen balance maintained between land, sea, and atmosphere. This was done through a process called denitrification. However, human activity has caused high levels of nitrogen in the earth’s oceans.
When fertilizer and sewage make their way into the ocean, it produces areas where there is simply too much nitrogen. This produces fish kills, toxic algae blooms, shellfish poisoning, and loss of coral reefs, seagrass meadows, and other coastal habitats.
One of the denitrification processes is handled by microbes found on seabeds of continental shelves. Interestingly the Arctic, which only accounts for 1 percent of these shelves, is actually responsible for 5 percent of global ocean nitrogen removal.
“The role of this region is critically important to understand as humans put more nitrogen into the ocean,” says Amber Hardison of the University of Texas at Austin, one of the authors of the paper. “The Arctic is also undergoing dramatic changes linked to climate change, including a rapid decline in sea ice. As sea ice shrinks, it disrupts the natural functioning of the ecosystem, including potentially limiting the vital nitrogen removal process.”
Animals living on and in the seafloor also play a role in denitrifiation. These creatures, including worms and clams, make tubes and burrows in the seabed, which makes a space for the microbes to do their job.
This new information might help us to better understand how ocean nitrogen removal works, as well as how our on actions impact it. By studying the microbes in the Arctic seabed, scientists can get a better understanding of how this denitrification process works. Then, by comparing them to other, similar microbes, they can get an idea of why Arctic microbes are so much better at denitrification. This could help them come to a conclusion about how to assist that process, which could help us offset the extra nitrogen that we’ve been leaking into the ocean.
This also means that protecting the Arctic is even more important. Oil and gas companies have been eyeing Arctic waters as a possible place to find untapped quantities of fossil fuels. They can only do because global climate change, brought about by the use of fossil fuels, has made those waters more accessible, but numerous scientists have argued that tapping such reserves could be bad for the Arctic and the world at large.