Microbial activity facilitates phosphorus adsorption to shallow lake sediment

Abstract

Purpose The phosphorus (P) level in sediments is one of the major indicators of the eutrophication of lakes. Little information is available on the effect of microbial activity on P adsorption in shallow lake sediments. In this study, we evaluated the effect of microbial activity on the adsorption of P to sediments in a shallow lake. Materials and methods The effect of microbes on P adsorption by lake sediment was examined using an incubation experiment. Sediment samples were collected from a eutrophic lake and sterilized by autoclaving. The sediment samples were inoculated and then incubated at various temperatures. Organic fractions of adsorbed P were analyzed to investigate the distribution of P in sediment. Results and discussion Microbial inoculation resulted in greater P adsorption in the sediment than sterilization in oxic conditions. This microbe-enhanced effect increased with temperature. The contribution of microbial inoculation to the maximum P adsorption values of the sterilized sediment increased with temperature at increments of 0.2, 12.3, 22.9, and 33.0 mg/kg for temperatures of 4°C, 20°C, 28°C, and 36°C, respectively. The concentrations of NaHCO 3 -IP, NaHCO 3 -OP, and Microbe-P in the inoculated sediments were significantly higher than those in the sterilized sediments, particularly Microbe-P, which was increased by more than 80%, indicating that P adsorption in the sediment was strongly influenced by microbial activity. The microbes release parts of P when oxic conditions change to anoxic conditions. Conclusions Our results demonstrate that the microbial activity could increase the adsorption of P in the sediment, especially under warmer temperatures and oxic conditions. It shows that sediment microbes could play an important role in the cycling of P in shallow lakes. These findings may lead to the development of an alternative technique to restore water quality in shallow lakes through microbial facilitated eco-remediation. Further work is needed to better understand the importance and mechanisms of this P fixation in situ.

Facilitation of phosphorus adsorption onto sediment by aquatic plant debris

“…It has been demonstrated that microbial processes are involved in the P flux between sediment and overlying water [13][14][15]. In addition, Boström et al [33] found that microbial biomass P accounts for up to 13% of total P in the surface sediment of Lake Vallentunasjön.…”

“…Recently, there has been evidence that biotic processes mediated by microorganisms are also involved in P cycling [13][14][15]. Therefore, any factors affecting the growth of microorganisms should also be expected to influence P cycling at the sediment/water interface.…”

Characterizing nutrient distributions and fluxes in a eutrophic reservoir, Midwestern United States

“…A considerable amount of P can be taken up by microorganisms in oxic conditions and transformed to cell biomass, particularly polyphosphate, which is the stored form of P in microbial cells (Huang et al, 2011). This phenomenon would both encourage continued flux of P to the water column via diffusion, and return P to the sediment as algae die and fall to the lake bottom.…”

Recent advances and future directions in soils and sediments research

“…Studies have also investigated the role of microbial activity in the sorption of chemicals to sediment, and how this may change due to variations in, for example, temperature and redox (e.g. Huang et al 2011). Further research is likely to focus on improving our understanding of chemical sorption and desorption to sediment under changing environmental conditions, including the role of changing flow regimes such as floods (Wölz et al 2010), and the role of thermodynamic and kinetic processes.…”