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8. As global temperatures continue to increase, is there anything that can be done in these arctic regions to mitigate the effect of GHG emissions?
I am not sure which human activities in the Arctic could mitigate GHG emissions. Temperatures in the Arctic are predicted to increase, and together with local moisture and vegetation changes, this will affect greenhouse gas exchange. It’s comparably easy to predict changes in temperature, but to determine changes in soil moisture is connected to large uncertainties. Yet, soil moisture and local hydrological conditions play a huge role in regulating greenhouse gas exchange. Greenhouse gas exchange is also connected to vegetation. I would say that, besides temperature, moisture and vegetation are the key factors regulating future Arctic greenhouse gas emissions. Future research should focus on improving projections of moisture and vegetation changes.
Source: University of Eastern Finland
measurements, for example a weather station logging the meteorological conditions at the site. We are collecting water samples to determine the concentration of nutrients and carbon in the soil pore water, and we are also measuring soil temperature, moisture and other surrounding parameters that help us to put the fl ux data into context later on and help us to explain the patterns we are observing.
the fi rst study that has found this warming-induced increase in nitrous oxide emissions from Arctic tundra
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4. Do you face any challenges whilst working in the Arctic conditions that make this research diffi cult?
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In the fi eld we are living without running water or electricity so the conditions are very basic. I have to say, I was worried when I was fi rst going out there to be living under these conditions, but I was really surprised by how quickly one can adapt to living like that, even within just a couple of days. I can’t say that I missed much other than certain kinds of food! Otherwise it was fairly easy to adapt.
You do have to be physically fi t, the work involves lots of walking. The tundra landscape has no roads or paths so there is a lot of walking with quite heavy backpacks. Other than that I found living out there quite easy.
It’s quite amazing to be living in nature with the feeling of freedom that you get from being so far away from everything. On top of that we were working in the North of Russia, which I think was an additional factor in the feeling of being in the wild, even feeling like an outlaw in a way!
5. What where the results of this study?
We have measured over two years, two summer growing seasons that we have been in the Arctic, mainly during July and August as this is the main growing period. We measured fl uxes of carbon dioxide, methane and nitrous oxide.
What we saw was that warming of only a few degrees centigrade increased fl uxes of all three greenhouse gases, not just carbon dioxide and methane but also nitrous oxide which was quite surprising - to our knowledge this is the fi rst study that has found this warming-induced increase in nitrous oxide emissions from Arctic tundra.
6. You say this was surprising, so can we assume these results weren’t completely what you were expecting?
to our knowledge this is
It’s surprising because nitrous oxide isn’t measured much in tundra. It’s quite a recent fi nding that Arctic soils might emit nitrous oxide – usually there are lots of monitoring stations in the Arctic that only focus on carbon dioxide and methane emissions, and nitrous oxide is generally not included in those measurements. Therefore there are only a few studies that have observed nitrous oxide emissions from tundra and now we showed that warming might increase those emissions. It was also surprising that just gentle surface warming increased the emissions of all three gases. For carbon dioxide and methane in particular, we observed increased concentrations of those gases even in the deeper soil profi le, where the warming treatment did not reach.
oxide, there is still a lack of knowledge about where throughout the Arctic nitrous oxide emissions occur, and
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under what particular current and future conditions.
7. What do the results of this research mean for the way we try to study and limit climate change?
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Even gentle warming, as is predicted for the short-term, can obviously promote emissions of all three greenhouse gases from tundra, including nitrous oxide. The response of vegetation to temperature played a large role in the changes in emissions that we observed. In terms of nitrous oxide, there is still a lack of knowledge about where throughout the Arctic nitrous oxide emissions occur, and under what particular current and future conditions. There are very few sites where nitrous oxide emissions have been measured. With this study we are hoping to encourage other research teams to include nitrous oxide fl uxes in their greenhouse gas budgets. It’s quite clear that arctic soils can be a source of nitrous oxide, but we need to identify those nitrous oxide emitting surfaces. In our study the main source of nitrous oxide were peatlands, uplifted permafrost peat soils, which store large amounts of nitrogen in the peat or in the organic soil layer. That is why, under favourable environmental conditions, these surfaces are sources of nitrous oxide.
It would be helpful to establish an extended network of measurement sites that measure nitrous oxide emissions from various surfaces in the Arctic, to generate further knowledge on Arctic nitrous oxide emissions.
In terms of nitrous
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nitrous oxide emissions are an unknown in Arctic biogeochemical cycling, and require further investigation.
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9. What is next for this research/your department? Have you any plans for expanding upon this study?
We have studies going on alongside this one – we have, for example, conducted detailed process studies, and are investigating the microbial communities at the site and how they are affected by warming. This will provide a valuable insight into soil processes that govern the changes we have observed above ground. We are also conducting lab studies focussing not only on what happens when the soil column is warming, but also what happens when the permafrost is starting to thaw, and how that, in turn, is affecting greenhouse gas production, consumption, or release.
10. And why do you think that up till now no-one has looked at nitrous oxide? A lack of technology, too much focus on carbon dioxide?
It’s not the technology as it’s fairly easy to measure, and measurements could easily be integrated into studies from existing measurement sites. But nitrous oxide emissions from tundra were only fi rst observed in 2009/2010. Not all surfaces emit nitrous oxide, so you do have to recognize the potential sources. The basis for nitrous oxide production in soils is a suffi cient supply of mineral nitrogen. Often Arctic soils are nitrogen limited. Organic soils and peatlands, however, store large amounts of nitrogen.
11. It mentions in your recent press release that nitrous oxide emissions are not incorporated in Arctic biogeochemical climate models, so in terms of modelling I assume you feel it should be taken
into account.
Yes, it should be, because in our studies we found a high potential of Arctic soils to emit nitrous oxide. Surely carbon dioxide and methane are the dominant greenhouse gases emitted in tundra, as nitrous oxide emissions might be small on a mass basis. But nitrous oxide is a strong greenhouse gas, about 300 times stronger than carbon dioxide on a 100-year time horizon, so even a small Arctic nitrous oxide source could be of importance. In any case, nitrous oxide emissions are an unknown in Arctic biogeochemical cycling, and require further investigation.
For further information, please contact:
M.Sc. Carolina Voigt (PhD student, main author), tel.: +358 505628735,
carolina.voigt@uef.fi , Dr. Christina Biasi (Research Director), tel: +358 403553810,
christina.biasi@
uef.fi Dr. Maija Marushchak (Postdoctoral Researcher), tel: +358 504135442,
maija.marushchak@
uef.fi
Research article: Voigt, C., Lamprecht, R. E., Marushchak, M. E., Lind, S. E., Novakovskiy, Alexander, Aurela, M., Martikainen, P. J., Biasi, C. 2016: Warming of subarctic tundra increases emissions of all three important greenhouse gases – carbon dioxide, methane and nitrous oxide. Global Change Biology. DOI: 10.1111/gcb.13563
www.envirotech-online.com AET Annual Buyers Guide 2017
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