Cyanobacteria-Mediated Arsenic Redox Dynamics Is Regulated by Phosphate in Aquatic Environments

Studies of cyanobacteria in environments where arsenic (As) and phosphate (P) both occur in significant concentrations have so far only focused on the effect of P on As­(V) toxicity and bioaccumulation, with little attention to the influence of P on As redox transformations. Our study revealed that As­(III) oxidation by <i>Synechocystis</i> appeared to be more effective with increased P levels. We demonstrated that the higher As­(III) percentage in the medium under P-limited conditions was due to enhanced As­(V) uptake and the subsequent efflux of intracellularly reduced As­(III) which in turn contributed to higher As­(III) concentrations in the medium. Arsenic redox changes by <i>Synechocystis</i> under P-limited conditions is a dynamic cyclic process that includes the following: surface As­(III) oxidation (either in the periplasm or near the outer membrane), As­(V) uptake, intracellular As­(V) reduction, and As­(III) efflux. These observations not only expand our understanding of how P influences microbial As redox metabolisms but also provide insights into the biogeochemical coupling between As and P in As contaminated eutrophic aquatic environments and artificial wetland-paddy fields

Testing Results of Precision Ratio of TGB Based-on SPOT5 Image.

<p>Testing Results of Precision Ratio of TGB Based-on SPOT5 Image.</p

Factors loading rotation matrix of varimax.

<p>Note: B1, B2 are visible bands, where B1 can detect absorption and reflectance of plant green hormone, and B2 belongs to the red light zone capable of distinguishing the color of different types of vegetation from the color difference; Where B3 is near-infrared bands, which can reflect the sensitivity of plants to chlorophyll by the correlation between some acquired strong information and factors like leaf area index and biomass; SWIR (short-wave (length) infrared (band)); NDVI (Normalized Difference Vegetation Index); SAVI (Soil-Adjusted Vegetation Index); MSAVI (Modified Soil-Adjusted Vegetation Index).</p

Cumulative probability distribution map.

<p>Cumulative probability distribution map.</p

Mimic diagram of three-dimensional laser scanning method for measuring the crown volume.

<p>Mimic diagram of three-dimensional laser scanning method for measuring the crown volume.</p

3D point cloud data.

<p>3D point cloud data.</p

Correlation coefficient of broadleaf tree volume and RS factors.

<p>Correlation coefficient of broadleaf tree volume and RS factors.</p

Mimic diagram of measuring crown cross-sectional area.

<p>Mimic diagram of measuring crown cross-sectional area.</p

Interpretation signs.

<p>Coniferous forest, Broad-leaved forest, Grass, Farmland, Water, Building land and other lands are signed in the figure.</p

Correlation coefficient of conifer volume and RS factors.

<p>Correlation coefficient of conifer volume and RS factors.</p