Researchers have just discovered that animals in the Arctic Ocean are responsible for more nitrogen cycling than previously believed. Organisms on the Arctic seafloor remove unexpectedly large amounts of nitrogen from the ocean. The details are in a paper that was published in the journal Nature Communications.
Nitrogen is removed from the environment through a process called nitrogen cycling. Beneficial bacteria convert the nitrogen into forms that can be released into the atmosphere or used by plants. As human activity results in an excess of nitrogen, these processes become especially critical. Sewage, run-off from fertilizers, and the use of fossil fuels all contribute to global nitrogen concentrations. High amounts can harm living organisms, including fish and other aquatic animals. Most nitrogen cycling occurs on the continental shelves in the ocean.
A team of researchers from The University of Texas at Austin collected data from the Chukchi Sea, part of the Arctic Ocean. They found that microbes in the area were removing huge concentrations of nitrogen, much more than expected. The team discovered that seafloor animals played a large role. Burrowing invertebrates, including worms and clams, create ideal spaces for denitrifying bacteria to colonize. A worm species called Maldane sarsi, for example, builds tubes and increases the overall surface area available for bacteria. This was the first major study to link these animals with nitrogen cycling microbes.
The team’s findings highlight the importance of the Arctic region in global nitrogen cycling. As climate change continues to melt Arctic ice, critical microbes and animals may be impacted. The same areas are rich in gas and oil reserves but are currently protected by law. The study shows why these protections are necessary, especially as humans release excess nitrogen into the environment. The research team emphasizes that these regions need to be monitored as global warming begins to affect local species.
McTigue ND, Gardner WS, Dunton KH, Hardison AK. Biotic and abiotic controls on co-occurring nitrogen cycling processes in shallow Arctic shelf sediments. Nature Communications (2016).