Climate change study heats up arctic soil
Climate change is a hot topic, and the issue is even “hotter” in the arctic since vast carbon stores make the north more sensitive to rising global temperatures.
Predictions for a global temperature increase within the next 100 years range anywhere from 2 to 10°C. In this warmer future, how will the planet maintain its delicate relationship with the atmosphere? What are the implications for agriculture on which humans depend for survival?
Researchers at the Bioforsk complex in the Pasvik valley just completed installation of a system to test this temperature flux and show what the effects might be on food production for populations in the high north and measure changes in greenhouse gas emissions.
“We want to find out how rising temperatures will affect soil processes and carbon dioxide emissions,” project manager Hanna Silvenoinnen told BarentsObserver. “There could be higher agricultural production, which would be a positive result, but there could also be higher emissions of greenhouse gases.”
The Svanhovd Bioforsk complex where the experiment takes place is located at the western edge of the Russian taiga and was established in 1934 as an agricultural research station to stimulate increased settlement in the area. Productive agriculture developed in the region over a century ago remains active today, with dozens of commercial farming companies producing food in the carbon-rich, although rocky, clay soils.
While farming in the area is a productive food source, the valley is also threatened by pollutants from the mining plant located in Nikel just 7 kilometers away. The Bioforsk study will assess not only the impact of climate change but also pollution-induced stress and build-up of heavy metals in the soil.
To find out what the changes look like, plots of meadow are heated up by three degrees Celsius and monitored by a complex system of sensors and imaging devices in the field, remote satellite imagery from above and laboratory tests of soil samples. A collaboration of a dozen scientists across Norway will keep track of plant production, soil moisture, nutrients, microbial communities, heavy metal concentrations and greenhouse gas emissions in the soil and in the air above the heated sites.
What they learn about the behavior of plants and soils in a warmer environment will help them understand how the earth’s net ecosystem carbon exchange will function in the future. The key is finding out if a heated plot of earth becomes a carbon sink or a carbon source.
Sink or Source?
The Earth’s carbon cycle is a constant transformation of carbon - whether by organisms, natural processes or human activity - from land and sea to the atmosphere and back to storage below the surface of the earth. Temperature is a major factor that affects the whole process.
Greenhouse gases that cause the temperature of the earth to rise are carbon dioxide, methane and nitrous oxide. Levels of carbon dioxide in the atmosphere depend on processes performed by plants and microbes, the tiny organisms that live in the soil. For instance, plants take carbon dioxide and turn it into oxygen through the process of photosynthesis. Microbe function varies depending on the species – some may use carbon dioxide, others may produce it, while others are more dependent on gases like oxygen or methane.
“Extreme temperature influences the activity of the microbes and what kinds can survive there. Who lives in the soil and what do they do? We want to measure both,” Silvennoinen says.
At the Svanhovd experiment, researchers measure the carbon dioxide emissions from the site in order to assess the change in how plants process carbon dioxide and how the microbes in soil react when the soil is heated. The overall carbon exchange on the sites - whether the sites do more to produce carbon dioxide or to store it – is an important indicator of whether climate change will turn the land into a system of helping or hurting.
“Will the higher temperature increase the microbial processes in the soil so that we get more carbon dioxide emissions, which further enhances climate change?” Silvennoinen asks in the experiment. “Once we measure the photosynthesis of the plants and the carbon dioxide emissions, then we have a picture of the total carbon exchange going on over the whole site – whether the plots function as a sink or a source of carbon dioxide.”
The researchers also want to look on top of the soil, at the plants themselves, to see how the heat affects production and whether different types of plants will grow. The Norwegian Institute for Nature Research will assist by using satellite imagery to look around the sites in the meadow as well as meadows in the area all the way to Nickel in order to see differences. The experiment also involves the use of an NDVI infrared camera and hyper spectral analysis to see different wavelengths of light reflected by the plants which offer clues about plant health.
What about carbon?
An additional element to the Meadow Warm experiment beyond measuring plant and soil activity is to test ways to proactively decrease carbon in the earth and air rather than leaving it to natural processes. Dead material such as grass clippings or woodchips becomes biomass as it decomposes, and it will eventually turn into carbon dioxide as it breaks down. A new technology under study around the globe is one that stops this process therefore decreasing carbon dioxide: bio char.
Bio char is essentially charcoal, and using it in farming is not a new technology. Natives in Latin America, Finland and the Amazon, for example, have used burned material to increase production, balance the pH in soils or increase water retention. New technology is creating the bio char in laboratories – burning biomass under oxygen-less conditions creates charcoal that is stable and does not break down in the environment as quickly, thus storing the carbon inside for longer periods of time.
Bio char has become popular over the last five years, and it can be made of a variety of materials with different results. Half of each plot of meadow at the Svanhovd experiment is also treated with bio char to measure its effects under heated conditions.
“We will also test if the bio char holds heavy metals so we don’t get them into circulation in the environment,” Silvennoinen said. Plant roots will be tested for heavy metal content, and the behavior of soil microbes in the presence of heavy metals will be assessed throughout the project. The project manager emphasizes that studies tailored to the high north region are increasingly important.
“There is a lot of carbon in the soils here in the Arctic, and they are very sensitive. Based on research, the effects of warming will be very high here,” she says. “What is the implication on agriculture and on climate change? It’s a rather interesting question: how can the farmer adapt?”