Project 12

Changes in river transport of Fe and other metals due to permafrost thawing

Lead partner: Swedish Museum of Natural History, Sweden
Marie Curie fellow: Catherine Hirst, UK (ESR, PhD student)

Organic material derived from peat has strong chelating ligands that enhance the weathering rates of iron-silicate minerals and greatly increase the solubility and transport of metals, such as iron, in river water. Vast areas of the Northern Hemisphere are covered by peatland. Much of these areas are underlain by permafrost and increased temperature will induce thawing and subsequent release of carbon into rivers.

The project will determine how thawing affects delivery of metals both from natural sources and from sites affected by the mining industry. Through investigation of larger particles, colloids, and dissolved phases in rivers, and considering the effects of photoreduction and bacterial degradation, the importance of organic phases for iron and trace metal transport will be evaluated. Samples from Northern Scandinavia and Siberia will be compared using state of the art size-fractionation for phase separation as well as the application of high-precision isotope and elemental analyses to formulate fingerprints for particular forms of metal association and transport. This data will be essential for monitoring the changes already occurring.