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You are here : eLibrary : IAHR World Congress Proceedings : 36th Congress - The Hague (2015) ALL CONTENT : Sediment management and morphodynamics : Anthropogenic nutrient leaching alters the size distribution of suspended particle matter
Anthropogenic nutrient leaching alters the size distribution of suspended particle matter
Author : FIONA H.M. TANG(1) & FEDERICO MAGGI(1)
ABSTRACT
The increased mineral fertilizer application rate in agriculture has been identified to result in the leaching of excessive
nutrients from land into natural water bodies, to promote growth of aqueous micro-organisms, and to cause eutrophication.
These processes not only have large scale repercussions on the ecosystems, but their effects also scale down to the
small-scale dynamics of suspended particle matter (SPM), eventually affecting the deposition and transport of SPM. The
understanding of the SPM response to an increased nutrient load and rapid microbial growth is crucial in monitoring and
managing water quality and tracking chemicals and microbially-derived compounds in natural waters. Hence, we present
here an experimental facility newly-designed and recently built in the School of Civil Engineering at the University of
Sydney, which has been used to investigate the effects of nutrient load on the biological phase of the SPM and,
consequently, on SPM flocculation dynamics. This facility is unique as it was designed to allow full control of sediment
concentration, nutrient concentration and turbulent shear, and was equipped with an automatic ¦ĚPIV system to acquire
micro photographs of suspended aggregates. In this study, we tested the effects of suspension type (biomass-free or
biomass-affected), turbulence and sediment concentration on SPM size distribution. Our results show that the presence of
nutrients and biological matter in SPM resulted in larger average floc size and higher standard deviation compared to
mineral SPM alone. The differences in SPM characteristic between biomass-free and biomass-affected SPM were found
to be less pronounced with increasing turbulent shear rate and decreasing sediment concentration.
File Size : 1,529,509 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 36th Congress - The Hague (2015) ALL CONTENT
Article : Sediment management and morphodynamics
Date Published : 19/08/2015
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