Connecting sources, fractions and algal availability of sediment phosphorus in shallow lakes: An approach to the criteria for sediment phosphorus concentrations.

Although point and nonpoint sources contribute roughly equal nutrient loads to lakes, their relative role in supporting algae growth has not been clarified. In this research, we have established a quantitative relationship between algae-available phosphorus (P) and P chemical fractions in sediments; the latter indicates the relative contribution of point versus nonpoint sources. Surface sediments from three large shallow lakes in eastern China, namely, the Chaohu, Taihu and Hongzehu Lakes, were sampled to assess their algae-available P and chemically extracted P fractions.

Enrichment of bioavailable phosphorus in fine particles when sediment resuspension hinders the ecological restoration of shallow eutrophic lakes.

Sediment resuspension is one of the main factors impacting the ecological restoration of shallow eutrophic lakes, but the mechanisms connecting suspended particles and algal growth have not been clarified. Our research presents an innovative approach based on P reallocation among particles with various sizes, considering the changes in redox and pH conditions from the sediments to the overlying water during resuspension. A lab-scale experiment was conducted to simulate P reallocation in particles during sediment resuspension by periodically dosing the system with P and/or organic carbon.

Distribution and adsorption of metals on different particle size fractions of sediments in a hydrodynamically disturbed canal.

Sediment resuspension widely occurs in environments with hydrodynamic disturbances, where particles are sieved into different grain size groups. The particles of different grain size exhibit heterogeneity of their physical, chemical or biological features. This research addressed the association of metals on size fractional particles sieved by sediment resuspension in a canal of Taihu basin, a highly urbanized and human-impacted area.