Mineral dust as a driver of carbon accumulation in northern latitudes

Malin Kylander (1) , A. Martínez-Cortizas (2) , Richard Bindler (3) , Joeri Kaal (2) , Jenny K Sjöström (1) , Sophia V. Hansson (4) , Noemí Silva-Sánchez (2) , Sarah L Greenwood (1) , Kerry Gallagher (5) , Johan Rydberg (3) , Carl-Magnus Mörth (1) , Sebastien Rauch (6)

1 Department of Geological Sciences [Stockholm]
2 USC - Universidade de Santiago de Compostela [Spain]
3 Department of Ecology and Environmental Science [Umeå]
4 Department of Bioscience [Roskilde]
5 GR - Géosciences Rennes
6 Chalmers University of Technology [Göteborg]

Peatlands in northern latitudes sequester one third of the world's soil organic carbon. Mineral dusts can affect the primary productivity of terrestrial systems through nutrient transport but this process has not yet been documented in these peat-rich regions. Here we analysed organic and inorganic fractions of an 8900-year-old sequence from Store Mosse (the " Great Bog ") in southern Sweden. Between 5420 and 4550 cal yr BP, we observe a seven-fold increase in net peat-accumulation rates corresponding to a maximum carbon-burial rate of 150 g C m −2 yr −1 – more than six times the global average. This high peat accumulation event occurs in parallel with a distinct change in the character of the dust deposited on the bog, which moves from being dominated by clay minerals to less weathered, phosphate and feldspar minerals. We hypothesize that this shift boosted nutrient input to the bog and stimulated ecosystem productivity. This study shows that diffuse sources and dust dynamics in northern temperate latitudes, often overlooked by the dust community in favour of arid and semi-arid regions, can be important drivers of peatland carbon accumulation and by extension, global climate, warranting further consideration in predictions of future climate variability.

Domaines: Sciences de la Terre

Malin Kylander, A. Martínez-Cortizas, Richard Bindler, Joeri Kaal, Jenny K Sjöström, et al.. Mineral dust as a driver of carbon accumulation in northern latitudes. Scientific Reports, 2018, 8 (1), pp.6876. ⟨10.1038/s41598-018-25162-9⟩. ⟨insu-01783713⟩