Nanoparticles and colloids as vectors of P-losses and -redistribution during forest ecosystem development

Nanoparticles and colloids (NPCs) act as vectors of P losses and redistribution in forest ecosystems, but key quantitative information linking environmental drivers to the fate, transport, composition of NPCs and associated P in forest systems is still missing. It is proposed that hydrologically driven NPCs losses and redistribution induce a long term ability for forest systems to sustain their biogeochemical P recycling flux and hence ecosystem nutrition.

It is hypothesized that colloids formed in forest ecosystems are mainly derived from organic surface layers, that lateral flow of colloidal P during storm flow events limits the maximum P recycling efficiency of forest ecosystems and that P is predominantly associated with organic colloids and largely bioavailable. Transport pathways are to be confirmed through stream water analysis. Further the transfer of colloids create a redistribution of P in forest stands from elevated terrain positions to depressions and from organic surface layers to mineral subsoils; with a lockdown of P in the latter horizons. The concentrations and composition of colloids will be analyzed in water samples collected in forest streams, in trenches capturing lateral flow of water, in soil column leachates and water dispersible colloids of soils at the Bad Brückenau, Conventwald, Vessertal and Mitterfels sites. Colloids will be fractionated and isolated using Field Flow Fractionation (FFF) in combination with inductively coupled plasma mass spectroscopy (ICP-MS), organic carbon analysis, and transmission electron microscopy in combination with energy dispersive spectroscopy (TEM-EDX).

For further information, see:
Jülich Forschungszentrum - Institute of Bio- and Geosciences
Forschungszentrum Jülich - Biogeochemical interfaces and colloids