A groundbreaking study from NYU Tandon School of Engineering uncovers how climate change is drastically altering nitrogen composition in Arctic rivers, posing a threat to marine ecosystems and Indigenous communities. The research calls for urgent climate adaptation measures.
Climate change is depriving the Arctic Ocean of critical nutrients as the region’s largest rivers deliver much less of the essential nitrogen that marine ecosystems need. This alarming trend has been highlighted in a new study led by Bridger J. Ruyle of NYU Tandon School of Engineering, which has been published in Global Biogeochemical Cycles.
“This is a red flag for the Arctic,” Ruyle said in a news release.
Ruyle conducted the study as a postdoctoral fellow at the Carnegie Institution for Science and joined NYU Tandon in the summer of 2025 as an assistant professor in the Civil and Urban Engineering Department.
The research emphasizes that rapid changes in river nitrogen chemistry could drastically transform the functioning of marine ecosystems in the Arctic, posing a grave threat to coastal food webs that have sustained Indigenous communities for millennia.
Based on 20 years of data from six major Arctic rivers — Yenisey, Lena, Ob’, Mackenzie, Yukon and Kolyma — the study found a significant decline in inorganic nitrogen between 2003 and 2023.
Inorganically-bound nitrogen, essential for the region’s primary production, was replaced by a form less available to marine life, potentially triggering cascading effects throughout the Arctic ecosystem.
The advance of rising temperatures and thawing permafrost are altering the chemical makeup of Arctic river water, resulting in a shift from inorganic to dissolved organic nitrogen.
Using advanced statistical modeling, the researchers pinpointed permafrost loss as a key driver behind these changes. Ruyle’s team combined observational water chemistry data with factors such as temperature, precipitation and land cover to uncover how climate is impacting nitrogen cycles in these waterways.
“Whether we’re looking at PFAS contamination in drinking water or nitrogen cycling in Arctic rivers, the common thread is understanding how environmental changes propagate through water systems,” Ruyle added.
The changes in nitrogen composition have significant implications for the region’s marine food webs, which depend heavily on nutrient input from rivers and are crucial for the food security of Indigenous communities.
The research underscores the urgent need for ecosystem management and climate adaptation strategies. As Ruyle noted, we must consider water quality and climate change as interconnected challenges.
“This work demonstrates why we need to think about water quality and climate change as fundamentally linked challenges,” added Ruyle. “As climate change intensifies, we must understand these interconnections to protect both human health and ecosystem integrity.”
Ruyle’s work extends beyond the Arctic, aiming to understand the broader implications of human activity and climate change on global water quality. This includes tracking contaminants such as “forever chemicals” and pharmaceuticals in wastewater, further illustrating how climate-driven changes affect water systems around the world.
Other co-authors of the study are Julian Merder of the University of Canterbury, New Zealand; Robert G.M. Spencer of Florida State University; James W. McClelland of the Marine Biological Laboratory, Woods Hole; Suzanne E. Tank of the University of Alberta and Anna M. Michalak of Carnegie Institution for Science.
Source: NYU Tandon School of Engineering