Although chlorinated organophosphate esters (Cl-OPEs) have been reported to be ubiquitously distributed in various anoxic environments, little information is available on their fate under anoxic conditions. In this study, we report two Dehalococcoides-containing enrichment cultures that transformed 3.88 ± 0.22 μmol tris(2-chloroethyl) phosphate (TCEP) and 2.61 ± 0.02 μmol tris(1-chloro-2-propyl) phosphate (TCPP) within 10 days. Based on the identification of the transformed products and deuteration experiments, we inferred that TCEP may be transformed to generate bis(2-chloroethyl) phosphate and ethene via one-electron transfer (radical mechanism), followed by C−O bond cleavage. Ethene was subsequently reduced to ethane. Similarly, TCPP was transformed to form bis(1-chloro-2-propyl) phosphate and propene. 16S rRNA gene amplicon sequencing and quantitative polymerase chain reaction analysis revealed that Dehalococcoides was the predominant contributor to the transformation of TCEP and TCPP. Two draft genomes of Dehalococcoides assembled from the metagenomes of the TCEP-and TCPP-transforming enrichment cultures contained 14 and 15 putative reductive dehalogenase (rdh) genes, respectively. Most of these rdh genes were actively transcribed, suggesting that they might contribute to the transformation of TCEP and TCPP. Taken together, this study provides insights into the role of Dehalococcoides during the transformation of representative Cl-OPEs.
Poyang Lake is an essential natural wetland in the Yangtze River basin
and plays a vital role in maintaining the ecosystem function and
ecological security in the middle and lower reaches of the Yangtze
River. However, the relative importance and spatial heterogeneity of the
impacts of human activities and land use changes on ecological security
needs to be further explored. Here, we analyzed the habitat quality
level around Poyang Lake in 2022 and explored the factors of habitat
quality change from a geographical perspective. The land use structure
changes around the Poyang Lake basin from 2000 to 2022 were
quantitatively analyzed, and then the relative importance and spatial
heterogeneity of each factor on ecological security changes were
investigated using geographic probes. The results show that (1) The
worst quality habitat (0–0.1) consists mainly of construction land
(1624.9 km2) with an area of 1634.64 km2; (2) Construction land
continues to increase with the most significant change, and the dynamic
land use attitude is 0.47. Grassland and mudflats have the greatest
decrease. The increase in cultivated land in different periods is mainly
due to the shift of water surface and forest land; (3) Wetland land use
change drivers are more influenced by the interaction of socioeconomic
factors. The explanatory degrees of the interaction between population
density and total year-end population and population density and
administrative area are greater than 0.84. The data are greater than the
explanatory degrees of every single factor, indicating that the land use
change is mainly coupled with population density, total year-end
population, and administrative area. These results reveal that human
activities influence the degradation of wetlands around the Poyang Lake
area. This study has significant reference value for coordinating
human–land relationships in Poyang Lake, optimizing land management
policy, and improving the sustainable development of cities
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