Flocculated meltwater particles control Arctic land-sea fluxes of labile iron

Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our result...

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Bibliographic Details
Published in:Scientific Reports
Main Authors: Markussen, Thor Nygaard, Elberling, Bo, Winter, Christian, Andersen, Thorbjørn Joest
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Online Access:https://curis.ku.dk/portal/da/publications/flocculated-meltwater-particles-control-arctic-landsea-fluxes-of-labile-iron(27bd6b82-6117-458b-8dd1-c09d13a41869).html
https://doi.org/10.1038/srep24033
https://curis.ku.dk/ws/files/167888269/srep24033.pdf
Description
Summary:Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our results reveal how flocculation (particle aggregation) involving labile iron may increase horizontal transport rather than enhance deposition close to the source. This is shown by combining field observations in Disko Fjord, West Greenland, and laboratory experiments. Our data show how labile iron affects floc sizes, shapes and densities and consequently yields low settling velocities and extended sediment plumes. We highlight the importance of understanding the flocculation mechanisms when examining fluxes of meltwater transported iron in polar regions today and in the future, and we underline the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters.