Water and sediment quality in Qinghai Lake, China: a revisit after half a century.

Qinghai Lake, situated on the Qinghai-Tibet plateau, is the largest lake in China. In this study, the water and sediment quality were investigated in Qinghai Lake, three sublakes, and five major tributaries. Both Na+ and Cl- were found to be the major ions present in Qinghai Lake and the three sublakes, while Ca2+ and HCO3- dominated the tributaries. Compared with historical data from the 1960s, the concentrations of NH4 (+), NO3 (-), and soluble reactive silica have increased considerably, likely caused by increased human activities in the area. Compared to the historical data, chemical oxygen demand has increased and lake water transparency has decreased, likely related to an increase in nutrient levels. Relatively high concentrations of total nitrogen (TN) and total phosphorus (TP) were observed in Qinghai Lake sediments, although P fraction types and low water concentrations of these two indicate low possibility of transfer into the water column. The ratios of C/N suggest that the organic matter in the sediments are primarily from autochthonous sources. TN and total organic carbon in the sediment cores increased slowly up the core while TP and total inorganic carbon have been fairly constant

Effects of sediment dredging on internal phosphorus: A comparative field study focused on iron and phosphorus forms in sediments

Sediment dredging is a controversial technology for eutrophication control. Its effects on phosphorus (P) cycling are still unclear. In this study, a long term 3 year field investigation was conducted at Dongqian Lake, China, following a sediment dredging project. The amount of iron (Fe) and P forms presented in the sediment from a dredged region (Y region) and a nearby un-dredged region (N region) were monitored and compared. The results showed that soon after the sediment dredging, there were no significant differences in NH4Cl extractable P (NH4Cl-P), NaHCO3/Na2S2O4 extractable P (BD-P) and residual P (Res-P) levels between the Y and N region. However, NaOH extractable reactive P (NaOH-rP) and non-reactive P (NaOH-nrP) were higher, and HCl extractable P (HCl-P) was lower, in the N region than in the Y region. Three years after dredging, considerable reduction in Fe (P < 0.01) was observed in the surface sediment from the N region, contrarily the amount of Fe (P < 0.05) accreted in the newly formed surface sediment from the Y region. Compared with the first year after the sediment dredging, TP increased by 35.2 and 42.3 mg/kg in the sediment of Y and N regions in the third year, respectively. The increased amount of TP in sediments may result from external loadings and existed primarily in two bioavailable forms (BD-P and NaOH-rP) in both the Y region and the N region. This result indicated that it is better to conduct dredging after external P loading has been blocked. In addition, more BD-P and NaOH-rP accumulated in the N region than the Y region. The observed increase in BD-P and NaOH-rP in the N region may result from Fe- and aluminum-adsorbed P from the water column. Our study suggests that Fe cycling in lakes following sediment dredging is an important factor for understanding the environmental effects of sediment dredging. (C) 2015 Elsevier B.V. All rights reserved

Effectiveness and Mode of Action of Calcium Nitrate and Phoslock (R) in Phosphorus Control in Contaminated Sediment, a Microcosm Study

Calcium nitrate and a lanthanum-modified bentonite (Phoslock(R)) were investigated for their ability to control the release of phosphorus from contaminated sediment. Their effectiveness and mode of action were assessed using microcosm experiments by monitoring the variation of physiochemical parameters and phosphorus and nitrogen species over time following the treatment for 66 days. Phoslock(R) was more effective reducing phosphorus in overlaying water and controlling its release from sediment. Calcium nitrate improved redox condition at the sediment-water interface and temporally reduce phosphorus in overlaying water but phosphorus level returned back in a long run. Phosphorus fractionation suggested that Phoslock(R) converted mobile phosphorus to more stable species while calcium nitrate increased the fractions of mobile phosphorus species. Phoslock(R) generally showed no effect on nitrogen species. Whereas calcium nitrate temporally increased nitrate, nitrite, and ammonium concentrations but their concentrations quickly reduced likely due to the denitrification process. Results suggested that Phoslock(R) can be more effective in controlling the release of phosphorus from sediment than calcium nitrate. However, calcium nitrate can improve the redox condition at the sediment-water interface, which may provide other benefits such as stimulating biodegradation

Analysis of Multiplicity of Hypoxia-Inducible Factors in the Evolution of Triplophysa Fish (Osteichthyes: Nemacheilinae) Reveals Hypoxic Environments Adaptation to Tibetan Plateau

HIF (Hypoxia-inducible factor) gene family members function as master regulators of cellular and systemic oxygen homeostasis during changes in oxygen availability. Qinghai-Tibet Plateau is a natural laboratory for for long-term hypoxia and cold adaptation. In this context, T. scleroptera that is restricted to >3500 m high-altitude freshwater rivers was selected as the model to compare with a representative species from the plain, P. dabryanus. We cloned different HIF-alpha and carried out a phylogenetic analysis from invertebrates to vertebrates for identifying HIF-alpha genes and analyzing their evolutionary history. Intriguingly, the HIF-alpha has undergone gene duplications might be due to whole-genome duplication (WGD) events during evolution. PAML analysis indicated that HIF-1 alpha A was subjected to positive selection acted on specific sites in Triplophysa lineages. To investigate the relationship between hypoxia adaptation and the regulation of HIF-alpha stability by pVHL in plateau and plain fish, a series of experiments were carried out. Comparison the luciferase transcriptional activity and protein levels of HIF-alpha s and the differing interactions of HIF-alpha s with pVHL, show clear differences between plateau and plain fish. T. scleroptera pVHL could enhance HIF-alpha transcriptional activity under hypoxia, and functional validation through pVHL protein mutagenesis showed that these mutations increased the stability of HIF-alpha and its hetero dimerization affinity to ARNT. Our research shows that missense mutations of pVHL induced evolutionary molecular adaptation in Triplophysa fishes living in high altitude hypoxic environments

Dredging project caused short-term positive effects on lake ecosystem health: A five-year follow-up study at the integrated lake ecosystem level

Sediment dredging is a controversial technology for lake eutrophication control. A lengthy and holistic assessment is important to understand the effects of a dredging project on a lake ecosystem. In this study, a dredging project was followed for 5 years. To understand the variations of lake ecosystems before, during and after the project, water quality, phytoplankton, zooplanklon and benthic animal biomass were monitored; Four subindicators, including eco-exergy (Ex), structural eco-exergy (Ex(st)), buffer capacity of total phosphorus for phytoplankton (beta((TP)(phyto))) and trophic level index (TLI) were calculated and developed to an integrated ecosystem health indicator (EHI). The monitoring results showed that the dredging project caused many short-term positive effects such as decreased total nitrogen, total phosphorus, permanganate index and phytoplankton biomass throughout the entire lake water, increased Secchi disk depth in the whole lake and increased benthonic animal biomass in the nondredged regions. However, these positive effects disappeared overtime. Water chemistry and biomass returned to the initial state before dredging. EHI showed that the dredging project caused negative effects on the lake health in the dredged region at first. Subsequently, the health status of the entire lake, including the dredged and nondredged regions, improved until 1-2 years after the project finished. Because of the lack of other timely ecological restoration measures, the lake gradually returned to its initial health status. However, the health status in the dredged regions was only slightly better than before dredging and often worse than that of the nondredged regions. Our study suggested that dredging projects may only cause short-term positive effects on lake ecosystem health. The external interception and dredging ratio were important. A dredging project should be combined with other ecological lake restoration measures when the project has caused positive effects in a lake. (C) 2019 Elsevier B.V. All rights reserved.</p

Water and sediment quality in Qinghai Lake, China: a revisit after half a century

Qinghai Lake, situated on the Qinghai-Tibet plateau, is the largest lake in China. In this study, the water and sediment quality were investigated in Qinghai Lake, three sublakes, and five major tributaries. Both Na+ and Cl- were found to be the major ions present in Qinghai Lake and the three sublakes, while Ca2+ and HCO3- dominated the tributaries. Compared with historical data from the 1960s, the concentrations of NH4+, NO3-, and soluble reactive silica have increased considerably, likely caused by increased human activities in the area. Compared to the historical data, chemical oxygen demand has increased and lake water transparency has decreased, likely related to an increase in nutrient levels. Relatively high concentrations of total nitrogen (TN) and total phosphorus (TP) were observed in Qinghai Lake sediments, although P fraction types and low water concentrations of these two indicate low possibility of transfer into the water column. The ratios of C/N suggest that the organic matter in the sediments are primarily from autochthonous sources. TN and total organic carbon in the sediment cores increased slowly up the core while TP and total inorganic carbon have been fairly constant. &copy; 2013 Springer Science+Business Media Dordrecht.Qinghai Lake, situated on the Qinghai-Tibet plateau, is the largest lake in China. In this study, the water and sediment quality were investigated in Qinghai Lake, three sublakes, and five major tributaries. Both Na+ and Cl- were found to be the major ions present in Qinghai Lake and the three sublakes, while Ca2+ and HCO3- dominated the tributaries. Compared with historical data from the 1960s, the concentrations of NH4 (+), NO3 (-), and soluble reactive silica have increased considerably, likely caused by increased human activities in the area. Compared to the historical data, chemical oxygen demand has increased and lake water transparency has decreased, likely related to an increase in nutrient levels. Relatively high concentrations of total nitrogen (TN) and total phosphorus (TP) were observed in Qinghai Lake sediments, although P fraction types and low water concentrations of these two indicate low possibility of transfer into the water column. The ratios of C/N suggest that the organic matter in the sediments are primarily from autochthonous sources. TN and total organic carbon in the sediment cores increased slowly up the core while TP and total inorganic carbon have been fairly constant

Synthesis, Aggregation-Induced Emission, and Liquid Crystalline Structure of Tetraphenylethylene<b>–</b>Surfactant Complex via Ionic Self-Assembly

A novel tetraphenylethylene material with liquid crystalline (LC) helical structure and aggregation-induced emission (AIE) property was prepared by ionic self-assembly (ISA). The AIE activity, phase behavior, self-assembly structure, and molecular packing behavior of the complex were then elucidated via a combination of different experimental techniques such as UV–vis absorption spectra, photoluminescence spectra, differential scanning calorimetry, polarized optical microscopy, one- and two-dimensional X-ray diffraction, and Fourier transform infrared spectroscopy. The experimental results reveal that the ISA complex possesses high-efficiency luminescent property with quantum yield as high as 46% in solid state. Meanwhile, the complex could self-assemble into different interesting structures which are sensitive to peripheral chain motions. During heating, the complex takes a low-ordered helical supramolecular structure at ambient temperature and then forms another LC phase with high-ordered helical molecular stacking. These ordered hierarchical structures, in combination with the liquid crystallinity and excellent AIE property of the ISA complex, make it a promising material for fabrication of luminescent devices

Initial data release and announcement of the 10,000 Fish Genomes Project (Fish10K)

Background: With more than 30,000 species, fish-including bony, jawless, and cartilaginous fish-are the largest vertebrate group, and include some of the earliest vertebrates. Despite their critical roles in many ecosystems and human society, fish genomics lags behind work on birds and mammals. This severely limits our understanding of evolution and hinders progress on the conservation and sustainable utilization of fish. Results: Here, we announce the Fish10K project, a portion of the Earth BioGenome Project aiming to sequence 10,000 representative fish genomes in a systematic fashion within 10 years, and we officially welcome collaborators to join this effort. As a step towards this goal, we herein describe a feasible workflow for the procurement and storage of biospecimens, as well as sequencing and assembly strategies. Conclusions: To illustrate, we present the genomes of 10 fish species from a cohort of 93 species chosen for technology development