Science – Publications – Rúna Magnússon

For a recent overview of my work, find me on google scholar, researchgate or linkedin.

2023

Magnússon, R. Í., Groten, F., Bartholomeus, H., van Huissteden, K., & Heijmans, M. M. Tundra browning in the Indigirka Lowlands (North‐eastern Siberia) explained by drought, floods and small‐scale vegetation shifts. Journal of Geophysical Research: Biogeosciences, e2022JG007330. LINK.

Many Arctic regions show a so-called “greening”, which means that they appear greener in satellite images or show more abundant vegetation. Satellite records so far show one big exception: my former research area in Siberia is “browning” rapidly! We compared greenness of satellite images to local vegetation data, weather data and hydrological / geomorphological maps, and found that both drought and heavy rain- and snowfall were associated with a loss in greenness.
Magnússon, R. Í., Sass-Klaassen, U., Limpens, J., Karsanaev, S. V., Ras, S., van Huissteden, K., Blok, D., & Heijmans, M. M. P. D. (2023). Spatiotemporal variability in precipitation-growth association of Betula nana in the Siberian lowland tundra. Journal of Ecology, 00, 1– 23. LINK.

We compared tree-ring records of Betula nana (dwarf birch) from Kytalyk and weather data, and found that precipitation can be an important factor in the growth of this common Arctic shrub, but that its role depends very much on other factors, such as temperatures, position in the landscape (high and easily drained or low and easily inundated) and probably also conditions in the preceding years. This has important consequences, because it means that relations between growth and precipitation that are found for shrubs in one particular spot during a particular period do not necessarily translate well to other adjacent spots or future decades.
Hamm, A., Magnússon, R. Í., Khattak, A. J., & Frampton, A. (2023). Continentality determines warming or cooling impact of heavy rainfall events on permafrost. Nature Communications, 14(1), 3578. LINK.

Using a combination of literature review and thermal-hydrological modelling, Alex and I found that the impact of heavy rainfall events on permafrost is not so straightforward. In some of our earlier experimental work we found strong warming and thawing of permafrost, but not all studies report the same effect. We found out that this is likely strongly determined by a region’s baseline climate. Permafrost in continental regions, where summers get warmer but the permafrost is shallow, show warming, whereas more maritime sites with colder summers do not show much of an effect of rainfall at all.

PHD THESIS

“Greening, Browning or Drowning?” Permafrost – Vegetation – Climate Interactions in the Siberian Lowland Tundra. LINK.

2022

Magnússon, R.Í., Hamm, A., Karsanaev, Limpens, J. Kleijn, D., Frampton, A., Maximov, T.C. & Heijmans, M.M.P.D. (2022). Extremely wet summer events enhance permafrost thaw for multiple years in Siberian tundra. Nature Communications, 13, 1556. LINK.

We simulated heavy rain events using an irrigation set up on the Siberian tundra. Heavy rain is expected to occur more often as the Arctic is warming. We found that permafrost thawed much deeper and faster when the ground was irrigated, even in the years after the irrigation experiment.
Frost, G. V., M. J. Macander, U. S. Bhatt, L. T. Berner, J. W. Bjerke, H. E. Epstein, B. C. Forbes, S. J. Goetz, M. M. P. D. Heijmans, M. J. Lara, R. Í. Magnússon, T. Park, G. K. Phoenix, J. E. Pinzon, S. P. Serbin, H. Tømmervik, C. J. Tucker, D. A. Walker, and D. Yang. 2022. Tundra greenness [in “State of the Climate in 2021”]. Bulletin of the American Meteorological Society 103:S291–S293. LINK.

Since scientists have started monitoring the Arctic from above using satellite images, it became apparent that the Arctic is “greening”. Vegetation productivity seems to be increasing in a warmer climate. However, some regions show pronounced decreases in productivity (“browning”), among which the Indigirka Lowlands in Siberia, where I did my PhD research.
Heijmans, M. M. P. D., Magnússon, R. Í., Lara, M. J., Frost, G. V., Myers-Smith, I. H., van Huissteden, J., Jorgenson, M. T., Fedorov, A. N., Epstein, H. E., Lawrence, D. M., & Limpens, J. (2022). Tundra vegetation change and impacts on permafrost. Nature Reviews Earth & Environment, 3(1), 68-84. LINK.

Both plant communities and permafrost are changing rapidly as the Arctic is warming. The one affects the other very much: permafrost literally forms the foundation on which plants grow and determines local water flows. Plants in turn regulate air temperatures close to the ground and temperatures of the soil through insulating properties and effects on snow distribution. We summarized current knowledge on changes in plant growth across the Arctic, and how this can in turn affect the thawing of permafrost.
Vuorinen, K., Austrheim, G., Tremblay, J. P., Myers-Smith, I. H., Hortman, H. I., Frank, P., … Magnússon, R. Í., … & Speed, J. D. M. (2022). Growth rings show limited evidence for ungulates’ potential to suppress shrubs across the Arctic. Environmental Research Letters, 17, 034013. LINK.

Across the Arctic, shrubs are expanding their range and growing more vigorously in a warmer climate. Can larger herbivores such as reindeer or sheep suppress this “shrubification”? Tree ring evidence shows that these grazers have a limited effect on shrub growth, and mostly at intermediate temperature ranges within the Arctic biome. I contributed tree ring and climate data from our Siberian tundra site.

2021

Magnússon, R.Í., Limpens, J., Kleijn, D., van Huissteden, J., Maximov, T. C., Lobry, S. & Heijmans, M.M.P.D. (2021). Shrub decline and expansion of wetland vegetation revealed by very high resolution land cover change detection in the Siberian lowland tundra. Science of the Total Environment, 782, 146877. LINK.

I used several highly detailed satellite images taken between 2010 and 2019, combined with ground vegetation surveys, to assess changes in the occurrence of different types of plants in our Siberian tundra site. I found a decline in shrub area, contrary to what is happening in many other Arctic sites. Wetland species such as sedges and peat moss, as well as small open water features, were expanding. This likely implies that the permafrost soils are collapsing and ponding locally, and that methane emissions may be increasing in this area.
Van Huissteden, J., Teshebaeva, K., Cheung, Y., Magnússon, R.Í., Noorbergen, H., Karsanaev, S. V., Maximov, T.C., & Dolman, A. J. (2021). Geomorphology and InSAR-Tracked Surface Displacements in an Ice-Rich Yedoma Landscape. Frontiers in Earth Science, 9. LINK.

Using radar image processing techniques, colleagues from the VU Amsterdam quantified local elevation changes in our Siberian study site in high detail. Elevation changes appeared to result from thawing of ice rich permafrost, accelerated by flooding in early summer, but also from other processes such as sedimentation and shrinking and swelling of soils. I provided recent satellite images and contributed (a little bit 🙂 ) to the writing.

2020

Magnússon, R.Í., Limpens, J., van Huissteden, J., Kleijn, D., Maximov, T.C., Rotbarth, R., Sass-Klaassen, U. & Heijmans, M.M.P.D. (2020). Rapid vegetation succession and coupled permafrost dynamics in Arctic thaw ponds in the Siberian lowland tundra. Journal of Geophysical Research: Biogeosciences, 125(7), e2019JG005618. LINK.

The first published paper of my PhD! This paper evaluates results from my first field season on the tundra, where we assessed the plant community composition and abiotic conditions (such as wayter table depth and thaw depth) in thaw ponds of various ages. These thaw ponds form when ice-rich permafrost thaws and the ground surface collapses. We found that the ponds show a vegetation succession trajectory towards pest moss dominated states. Over this trajectory, thaw depths and surface subsidence are also reduced and small shrubs seem appear on the peat moss. Indications that the ground surface can likely recover, although this seems to require much more time (over 20 years) than the rapid, initial formation of the ponds.
Magnússon, R.Í., Cammeraat, E., Lücke, A., Jansen, B., Zimmer, A., & Recharte, J. (2020). Influence of glacial sediments on the chemical quality of surface water in the Ulta valley, Cordillera Blanca, Peru. Journal of Hydrology, 125027. LINK.

During my master’s in Earth Science at the University of Amsterdam, I sampled water and glacial sediments in the Peruvian Andes. In this area rock material is locally rich in pyrite, which can cause acidification and harmful levels of heavy metals in surface water that local communities rely on. As glaciers recede and glacial sediments are left exposed, surface water and ground water can flow through these sediments, which appears to alter the water’s chemical fingerprint. This makes pyrite-rich (fluvio)glacial sediments an overlooked but potentially important source of natural contamination.

2016

Magnússon, R.Í., Tietema, A., Cornelissen, J.H.C., Hefting, M.M., & Kalbitz, K. (2016). Tamm Review: Sequestration of carbon from coarse woody debris in forest soils. Forest Ecology and Management, 377, 1-15. LINK.

My very first published paper was a review article that I wrote for my master’s in Earth Science at the University of Amsterdam, evaluating whether leaving dead wood in the forest could enhance the storage of carbon in forest soils. Forests can be important sinks for carbon. As dead wood is left on the forest floor, carbon from the wood can enter the atmosphere as CO2, or enter the soil as dissolved carbon, via microbial biomass or physical mixing of dead wood fragments into the soil. Since so little was known about the exact magnitudes of such carbon pathways in different kinds of forests, we tried to use the review as a stepping stone towards a research proposal. Sadly, this proposal did not receive funding, and I went on to look for PhD positions elsewhere. I was very happy with this opportunity though and it is by far my most cited work.