Contrasting effects of MgAl- and MgFe-based layered double hydroxides on phosphorus mobilization and microbial communities in sediment.

The effects of two types of layered double hydroxides (LDH) in-situ treatment on sediment phosphorus (P) mobilization and microbial community's structure were studied comparatively. The results presented that magnesium/aluminum-based (MA) and magnesium/iron (MF)-based LDH displayed great phosphate uptake ability in aqueous solution in a broad pH range of 3-8. The maximum phosphate sorption capacity of MA was 64.

Improving in-stream nutrient retention potential through factitious manipulation: the stepping stone structures of flying-geese pattern and their reinforcement structures.

Small streams are essential parts of water ecosystems, such as rivers, lakes, and reservoirs, performing vital functions in the attenuation of nutrient pollution. As eutrophication becomes an increasingly severe problem in waters, it is necessary to investigate how to improve nutrient retention potential in streams. In this study, the effect of artificial manipulation was examined on transient storage and nutrient uptake in streams by setting up the stepping stone structures of flying-geese pattern (SG) and the combination mode of SG and bilaterally staggered spur dikes (SG+SD) in the channel.

[Contamination Assessment and Source Apportionment of Soil Heavy Metals in Typical Villages and Towns in a Nonferrous Metal Mining City].

To investigate the soil contamination degree and potential ecological risk level of heavy metals in villages and towns in Tongling City, we collected 67 surface soil samples (including surface dusts and river sediments) from the typical districts, namely Shun'an Town, Zhongming Town, and Yi'an Economic Development Zone, and measured the contents of heavy metals including Cu, Zn, Pb, Cr, Cd, As, and Ni. Then, spatial distribution characteristics of heavy metals were analyzed, and their contamination degree and potential ecological risk were assessed. Finally, source apportionment of soil heavy metals was conducted using factor analysis.

Nutrient retention in agricultural headwater stream: artificial manipulation of main-channel morphology and hydrologic condition.

To make up for the deficiency of transient storage and nutrient retention capacity of some headwater streams, some effective artificial measures have been developed to improve the stream ecosystem functions. But few studies have focused on the effects of artificial manipulation on nutrient retention in hydrologic and non-hydrologic processes of streams. In response, we selected an agricultural headwater stream in the Banqiao River tributary of Chaohu Lake Basin, artificially altered the flow pattern in the main-channel by introducing barriers which were composed of soil, coarse sand, and stones, and used the tracer experiment and OTIS (one-dimensional transport with inflow and storage) model to assess the transient storage potential of stream and the nutrient retention of hydrologic and non-hydrologic processes.

[Release Risk of Phosphorus by Sediments and Its Influencing Factors in Ponds and Ditches of a New Urban District Park].

This study examined five ponds and three ditches in the Shufengwan Sports Park in a new urban district of Hefei City, from which surface-layer sediments and overlying water samples were collected during autumn, winter, and summer. The equilibrium phosphate concentrations (EPC) of the sediments and its response to exogenous carbon or nitrogen were then measured. The resulting EPCvalues were used to assess the risk of phosphorus release by the sediments.

Assessing the potential and kinetics of coupled nutrients uptake in mesotrophic streams in Chaohu Lake Basin, China.

Interactions among multiple nutrients uptake certainly have a great effect on their retention in headwater streams, yet little research has been made to explore the quantitative characteristics of their interactions, especially in mesotrophic streams. In response, we conducted an identical series of instantaneous nutrient addition experiments, using ammonium nitrogen (NH-N) and phosphate phosphorus (PO-P) alone or together, in two mesotrophic agricultural headwater streams in Chaohu Lake Basin, China, to quantify the relationships between nutrient concentrations and uptake rates, and examine how NH-N and PO-P interact to affect their individual uptake. Both the Michaelis-Menten (M-M) equation and response surface model were utilized to analyze coupled NH-N and PO-P uptake patterns across a range of nutrient concentrations, by fitting the kinetic processes of NH-N and PO-P uptake in single- and dual-nutrient additions.

Revealing the hydrological transport and attenuation of 14 antibiotics in a low-flow stream.

The fate of antibiotics has mostly been studied in lab-scale systems. Few studies have precisely evaluated the attenuation of antibiotics in natural streams. We used Lagrangian sampling combined with a tracer test and one-dimensional transport with inflow and storage model (OTIS) to reveal the effects of dilution and self-attenuation processes, and diurnal variation of light on the degradation of 14 antibiotics in a 3.

[Phosphorus Forms and Release Risk of Sediments in Urban Sewage Treatment Plant Effluent and Receiving Stream Reach].

From October 2018 to April 2019, the surface sediment and overlying water samples were collected every two months from the upstream and downstream of the effluent outlet of the Caitianpu sewage treatment plant in the Banqiao River, Hefei City. The effects of the sewage treatment plant effluent on both phosphorus forms and the equilibrium phosphate concentration (EPC) in sediments were analyzed. The response of equilibrium phosphate concentration to external carbon (sodium acetate) and the release risk of phosphorus in sediments were investigated.

[Sediment Denitrification Rate and Its Response to Exogenous Carbon and Nitrogen in the Ponds and Bottomland of the Chaohu Lakeshore Zone].

From October 2018 to August 2019, three typical ponds and bottomland were selected in the Chaohu lakeshore zone, where surface sediments and overlying water samples were collected simultaneously. A set of incubation experiments, along with exogenous carbon and nitrogen concentration gradients, were conducted to analyze sediment denitrification rates and its response to carbon and nitrogen limitation. Moreover, the main influencing factors for the sediment denitrification process were identified using correlation analysis method.

Evaluating transient storage and associated nutrient retention in a nutrient-rich headwater stream: a case study in Lake Chaohu Basin, China.

Transient storage has been studied intensively in small streams, but some processes and mechanisms are not yet entirely understood regarding this issue, especially in chronically nutrient-enriched streams. The exploration of transient storage dynamics in nutrient-rich headwater streams has great significance for stream nutrient management in China and other developing countries, which are suffering from eutrophication. In the present study, we conducted five instantaneous slug additions composed of a conservative tracer dissolved with two nonconservative nutrients injections in a suburban small stream (Guanzhen Creek), Lake Chaohu Basin, China.

[Potential for Phosphorus Uptake by Bed Sediments and Its Response to Carbon Additions in the Shiwuli River, Chaohu Lake Basin].

Surficial sediments were collected from five sampling sites in the mainstream of the Shiwuli River along an urban-rural gradient in the Chaohu Lake basin during July 2017 (summer) and January 2018 (winter). The total uptake (SPU), abiotic uptake (SPU), and biotic uptake (SPU) of phosphorus by sediments were measured, and uptake responses to different carbon sources (i. e.

A genome-wide analysis of pentatricopeptide repeat (PPR) protein-encoding genes in four Gossypium species with an emphasis on their expression in floral buds, ovules, and fibers in upland cotton.

Cotton is the most important natural fiber used in textiles. Breeding for "three-lines", i.e.

Effects of channel morphology on nitrate retention in a headwater agricultural stream in Lake Chaohu Basin, China.

Five field tracer experiments and relevant detailed investigations of physical characterizations were conducted to investigate the effects of channel geomorphic settings on nitrate uptake efficiency on a 310-m long geomorphically distinct stream reach in a headwater agricultural stream in Hefei District, Lake Chaohu Basin. The model-fitted parameters from the one-dimensional transport with inflow and storage model were used to estimate the transient storage metric ([Formula: see text]) and determine the total nitrate uptake coefficient (k) for the study reach. And then, a nutrient spiraling approach was applied to reach-scale nitrate uptake estimates (S, V, and U).

[Nitrification Rates and Pollution Characteristics of Sediments with Different Geomorphic Features in the Shiwuli Stream, Chaohu Lake Basin].

Sediment and overlying water samples were collected seasonally from five different geomorphic structures (i.e., pools, riffles, gravel bars, point bars, and runs) from two urban reaches of the Shiwulihe River in the Chaohu Lake Basin dominated by high ammonia concentration between July 2017 and March 2018.

[Nitrate Uptake Kinetics and Correlation Analysis in an Agricultural Drainage Ditch].

To investigate the whole-reach nitrate (NO-N) uptake dynamics in a headwater agricultural stream, we performed five pulse tracer additions of a reactive solute (as KNO) and a conservative solute (as NaBr) in an agricultural drainage ditch in Hefei district, Chaohu Lake basin, from October 2016 to April 2017. The TASCC (tracer additions for spiraling curve characterization) approach and Michaelis-Menten (M-M) method were applied for the simulation of NO-N uptake dynamics. Results showed that the ambient areal rate of total NO-N uptake varied from 11.

[Nitrification and Denitrification Potential of Benthic Sediments in a Suburban Stream under Intense Human Disturbance Scenarios].

Water and benthic sediment samples were collected monthly from six sites over a 2-km reach in a first-order stream located in the northeastern rural-urban fringe of Hefei City, from May 2016 to January 2017. These sites were scattered in three stream reach types as natural pattern sections (Scenario 1), point source pollution sections (Scenario 2), and severe soil erosion sections (Scenario 3). The potential rates of nitrification and denitrification in the sediments were measured and variable characteristics were evaluated quarterly.

[Biotic and Abiotic Uptake of Phosphorus in Benthic Sediments of Suburban Streams Under Intense Human Disturbance Scenario].

To reveal the impact of land use change on the phosphorus uptake in benthic sediments of suburban streams, a headwater stream in the urban fringe of Hefei City was selected and a set of benthic sediments was collected monthly from the chosen stream reach from June to November 2016. An incubation method was applied to explore the biotic and abiotic uptake of phosphorus in benthic sediments under intense human disturbance scenario. Results showed that the uptake potentials in summer were higher than those in autumn, both for total (including biotic and abiotic) and abiotic uptake of phosphorus.

Expression profiles of a cytoplasmic male sterile line of Gossypium harknessii and its fertility restorer and maintainer lines revealed by RNA-Seq.

The Gossypium harknessii background cytoplasmic male sterility (CMS) system has been used in cotton hybrid breeding in China. However, the mechanism underlying pollen abortion and fertility restoration in CMS remains to be determined. In this study, we used RNA-seq to identify critical genes and pathways associated with CMS in G.

[Pollution Characteristics and Nitrification and Denitrification Potential of Superficial Sediments from Streams in an Urban-Rural Fringe].

From May 2015 to June 2016, seasonal sediment samples were collected from three headwater streams in the urban-rural fringe of Hefei, Chaohu Lake basin, China. The nitrogen pollution characteristics of sediments were preliminarily investigated for the three streams. Three metrics, that is, potential nitrification rate (PNR), areal nitrification rate (ANR) and rate of denitrification were quantitatively determined, and their spatial and temporal variations were discussed subsequently.

Cloning and Expression Analysis of Eight Upland Cotton Pentatricopeptide Repeat Family Genes.

The pentatricopeptide repeat (PPR) gene family is one of the largest gene families in plants. Most PPR genes are localized in mitochondria and chloroplasts functioning in regulation of plant growth and development, fertility restoration for cytoplasmic male sterility (CMS), and stress defense. In this study, using in silico cloning and PCR amplification with degenerate primers based on Arabidopsis PPR genes, we cloned eight new full-length PPR genes encoding protein sequences ranging from 458 to 875 amino acids, with 8 to 16 repetitive PPR elements in upland cotton and all of them lack introns.

[Fractions and Release Risk of Phosphorus in Surface Sediments of Three Headwater Streams with Different Styles of Water Supply].

From May to September 2015, seasonal sediment samples were collected from three headwater streams and ditches which were discharged from sewage plant tail water, food processing wastewater and agricultural drainage-groundwater seepage, respectively, in Hefei, Chaohu Lake basin. The stream-bed sediments were analyzed for phosphorus fractions. The risk assessment on phosphorus release from sediments was conducted using the phosphorus sorption index (PSI), degree of phosphorus saturation (DPS) and the phosphorus release risk index (ERI).

[Transient Storage Characteristics of Artificial Pool Geomorphic Structure in an Agricultural Headwater Stream].

From November 2015 to February 2016, five short-term tracer injections were performed with a conservative tracer (NaCl) in an agricultural headwater stream, Lake Chaohu basin. Thus the data sets of tracer experiments were finally employed for calculating the physical characteristics and transient storage metrics. Through the comparisons between the artificial pool reach and straight reach, characteristics of transient storage for the artificial pool geomorphic structure were interpreted and explored.

[Phosphorus Fractions and Release Risk in Surface Sediments of an Agricultural Headwater Stream System in Hefei Suburban, China].

A typical water system of agricultural headwater stream in Chaohu Lake basin was selected as the study area, and 17, 16, 14 and 13 surface sediments were collected from the four styles of stream, respectively, including ponds, branches, main channel and mainstream deep pools, in October 2014 (in autumn) and April 2015 (in spring). The forms and space-time variations of phosphorus in the sediments were analyzed. Clustering and variance analysis were conducted on the phosphorus forms data from the four styles of stream by means of multivariate statistical analyses.