When talking about nitrogen in the ecosystem, the problem is usually an excess caused by human activity, such as runoff into New Hampshire waterways. But on a global scale, the problem might be too little nitrogen entering the ecosystem due to the usual culprit: the burning of fossil fuels. In turn that could cut crop yields and plant output worldwide.
That’s a conclusion from a study co-authored by Scott Ollinger, a professor of natural resources at UNH. UNH Today has a full story here. A snippet:
Ollinger has been keeping tabs on nitrogen levels in the northeastern U.S. forests for decades, and he joined forces with international scientists to pore through data from the past 250 years for this study. Using samples from tree rings and plant foliage, lake sediments, gas fluxes from soils, and various other indicators, they compiled the nitrogen trends and saw a steady decline over the last century in regions as seemingly disparate as the central U.S. grasslands, northeastern forests, the Arctic and portions of Africa and Eurasia.
Ollinger is not completely shocked by the study results; 20 years ago, he worked on an ecological computer model that predicted the possibility of nitrogen decline due to rising atmospheric carbon dioxide levels. He believes that is now playing out on a wider scale. “This is yet another reason why we should focus on decreasing our emissions of carbon dioxide into the atmosphere, so we can help our ecosystems to behave like they are supposed to, like they once did,” he notes.
Did Ollinger supply any numbers? The atmosphere is roughly 78% nitrogen, 21% oxygen, and 1% other gases, mostly argon. Carbon dioxide, at only about 0.04%, could not displace appreciable amounts of any gas by any process, chemical or biological, or could it? Where is the nitrogen going, and how much of it? What are the implications of his findings? Too many questions unanswered here.
The full study is linked from the UNH story – I should have linked to it, as well. Like any good study that breaks ground it raises a lot of new questions – that’s how science works.