The delicate stability of the arctic soils is seriously threatened as a result of rising global temperatures. Several recent studies, led by international and Spanish research teams, show how the Heat is rapidly depleting nitrogen reserves present in these soils, which ultimately impacts plants' ability to grow and, above all, to absorb the carbon dioxide emitted by the ecosystems themselves. Traditionally, it was assumed that increased biological activity in the heat could offset some of the soil's CO2 emissions, but according to the most recent research, the reality is much more worrying.
The phenomenon has been studied in depth for a decade in Iceland, where the scientific team has taken advantage of natural geothermal gradients that simulate the conditions of increasing warming. It has been found that, far from improving, the soil loses storage capacity for essential nutrients, with nitrogen being the most affected. This has led to a significant decrease in fertility and a notable reduction in plant growth, preventing vegetation from compensating for the high levels of CO2 released by the action of soil-dwelling microorganisms.
A loss of nitrogen that makes a difference
Experts detail that by each degree that the ambient temperature increases Between 1,7% and 2,6% of soil nitrogen is lost. This is critical because it implies that as global warming progresses, the ability of Arctic soils to maintain their ecological functions will be increasingly reduced. Fertility decreases and vegetation is limited, accentuating the vicious circle of higher emissions and lower absorption of carbon dioxide.
Under normal conditions, Soil microorganisms are most active in spring and summer. They transform nitrogen into forms usable by plants, such as ammonium and nitrates. However, Rising temperatures cause these microorganisms to begin their activity much earlier., even in the middle of winter, when vegetation remains dormant due to low light. As a result, Nitrogen is released at a time when plants cannot absorb it, which causes their loss and, in part, their filtration into underground layers, with the risk of water contamination. To better understand the consequences of the change in these ecosystems, we recommend reading the article on Permafrost and its importance in the Arctic.
Part of Lost nitrogen can end up as nitrous oxide, a potent greenhouse gas. In fact, Nitrous oxide has a much greater impact than CO2 on the atmosphere, which represents an additional environmental challenge to the already complex situation in the Arctic in the context of climate change.
Thawing: the critical point of "leaks"
The most delicate moment of this process occurs during the thaw season. Just when nitrogen reserves are at their peak after winter, The plants have not yet begun to grow and absorb nutrients, facilitating the loss of much of this nitrogen. It is during this period that the greatest transfer of nitrogen out of the system occurs, both to deep waters—with the risk of eutrophication—and in the form of greenhouse gases into the atmosphere.
Heat not only reduces the amount but also the size of the microorganisms responsible for storing nitrogen and, in addition, reduces the presence of fine roots, which function as natural pantries of the element. In this way, Every year there are fewer reserves available for the next biological cycle, which accentuates the imbalance.
The importance of these investigations lies in the fact that, contrary to what was believed, the ability of Arctic ecosystems to offset emissions due to their own biological activity is much lower than estimated. The scientific community warns that if measures are not taken to limit global warming, Fertility losses and increased emissions could reach a point of no return.
Everything indicates that The Arctic is losing the battle against climate change and that the ability of these regions to function as carbon sinks could be seriously reduced if the current trend is not halted. Understanding this process is key to predicting how the planet's cold soils will evolve in the coming decades and to anticipating their effects on the global climate.
