4.7 Article

Adsorption of humic acids to lake sediments: Compositional fractionation, inhibitory effect of phosphate, and implications for lake eutrophication

Journal

JOURNAL OF HAZARDOUS MATERIALS
Volume 433, Issue -, Pages -

Publisher

ELSEVIER
DOI: 10.1016/j.jhazmat.2022.128791

Keywords

Functional group; Two-dimensional FTIR correlation spectroscopy (2D-FTIR-CoS); Eutrophication; Internal loading of phosphorus; Excitation-emission matrix fluorescence coupled with parallel factor analysis (EEM- PARAFAC)

Funding

  1. National Natural Science Foundation of China [41971139, 41930760, 41671099]

Ask authors/readers for more resources

This study investigates the interactions between humic acid (HA) and phosphate in the biogeochemical cycle of lakes. The results show that the functional groups of organic compounds not only control their fractionation and burial in sediments, but also their ability to replace phosphate. The study proposes a novel mechanism for the legacy effect of lake eutrophication, suggesting that increasing algae-derived organic compounds can promote the release of phosphate from sediments, sustaining internal phosphorus loading and lake eutrophication.
Humic acid (HA) and phosphate interactions play a vital role in the biogeochemical cycle of carbon and nutrients and thus the trophic state of a lake. The adsorption behavior of HAs to sediments in the absence and presence of phosphate was investigated in this study. Three types of HAs were used, AHA from algae-dominated lake sediments, MHA from macrophyte-dominated lake sediments, and a reference HA (RHA) with terrestrial sources. The adsorption capacity of lake sediments was highest for AHA, which can be explained by that AHA contained more carboxyl-containing molecules, proteinaceous compounds and polysaccharides that were preferentially adsorbed by minerals. Phosphate showed a stronger inhibitory effect on MHA adsorption than on AHA adsorption, suggesting that AHA can more effectively replace phosphate adsorbed to sediments. Our findings show that the functional groups of organic compounds control not only their fractionation and burial but also their ability to replace phosphate in sediments. We propose a novel mechanism to explain the legacy effect of lake eutrophication. That is, as lakes shift from a macrophyte-dominated state to more eutrophic, algae dominated state, increasing algae-derived organic compounds can promote the release of phosphate from sediments, forming a positive feedback loop that sustains internal phosphorus loading and hence lake eutrophication.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.7
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available