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Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems
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Groundwater controls on colloidal transport in forest stream waters
N Gottselig1, J Sohrt2, D Uhlig3
1Institute of Crop Science and Resource Conservation, Soil Science and Soil Ecology, University of Bonn, Nussallee 13, 53115 Bonn, Germany.
The Science of the Total Environment
|December 16, 2019
Summary
Seasonal variations in natural nanoparticles (NNP) and fine colloids in stream water reveal their sources. Groundwater significantly contributes to streamflow year-round, influencing elemental composition.
Area of Science:
- Environmental Science
- Geochemistry
- Hydrology
Background:
- Biogeochemical changes in catchments are reflected in stream water composition.
- Natural nanoparticles (NNP; 1-100 nm) and fine colloids (<300 nm) play a role in element transport.
- Understanding seasonal dynamics of colloids is crucial for catchment science.
Purpose of the Study:
- To investigate seasonal variations in NNP and fine colloids in stream water.
- To determine the origin of NNP and fine colloids based on catchment inflow parameters.
- To assess the role of different water compartments in NNP and fine colloid composition.
Main Methods:
- Annual monitoring of elemental composition of NNP and fine colloids in stream water, precipitation, groundwater, and subsurface flow.
- Analysis of meteorological and hydrological parameters.
- Quantification of org C, Al, Si, P, Ca, Mn, and Fe using Asymmetric Flow Field Flow Fractionation (AF4).
Main Results:
- Colloid-bound elements constituted up to 55% of total element concentrations.
- Highest NNP and fine colloid loads were observed during winter.
- Groundwater was identified as a consistent source of colloidal Ca in stream water.
Conclusions:
- Different water compartments exhibit distinct NNP and fine colloid compositions.
- NNP and fine colloids serve as effective indicators for identifying stream colloid sources.
- This study highlights the under-explored significance of NNP and fine colloids in forest watersheds.
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