Double effects of mitigating cyanobacterial blooms using modified clay technology: regulation and optimization of the microbial community structure.

Harmful algal blooms (HABs) are global hazards under global climate change and eutrophication conditions. Modified clay (MC) method is widely used to control HABs in Asian and American coastal waters. However, little research has been conducted on the underlying mechanisms by which MC controls blooms in freshwater environments.

Insights into the differential removal of various red tide organisms using modified clay: Influence of biocellular properties and mechanical interactions.

In recent years, red tides have increased worldwide in frequency, intensity, involving a higher number of causative species during the events. As the most commonly used method for control of red tides, modified clay (MC) was found to have differential ability to remove various red tide species. However, the underlying mechanisms have not yet been completely elucidated.

Insights into how characteristics of dissolved algal organic matter affect the efficiency of modified clay in controlling harmful algal blooms.

Dissolved algal organic matter (dAOM) originating from harmful algal blooms (HABs) can deteriorate the quality of municipal water supplies, threaten the health of aquatic environments, and interfere with modified clay (MC)-based HABs control measures. In this study, we explored the composition of dAOM from Prorocentrum donghaiense, a typical HAB organism, and assessed the influence of dAOM on MC flocculation. Our results suggested that dAOM composition was complex and had a wide molecular weight (MW) distribution.

Harvesting of Microcystis flos-aquae using chitosan coagulation: Influence of proton-active functional groups originating from extracellular and intracellular organic matter.

Algogenic organic matter (AOM) produced by Microcystis cells inhibits coagulation harvesting; however, the harvesting inhibitory mechanisms at the functional groups level remain to be determined. This study fractionated extracellular organic matter (EOM) and intercellular organic matter (IOM) from Microcystis flos-aquae into five different hydrophilic and hydrophobic fractions and investigated their inhibition of chitosan coagulation harvesting. The proton-active functional groups in the inhibitory fractions were further analysed by potentiometric titration, and the interaction between these functional groups and chitosan was elucidated.

Effect of shear rate on floc characteristics and concentration factors for the harvesting of Chlorella vulgaris using coagulation-flocculation-sedimentation.

Coagulation-based separation has been increasingly applied to microalgal harvesting because of its competitive cost and high scalability. The characteristics of flocs formed during coagulation/flocculation are critical for efficient harvesting. However, few studies have been devoted to systematically investigating the structural characteristics of microalgal flocs and their influences on subsequent settling performance.

[Responses of the Benthic Diatom Community to Nutrients and the Identification of Nutrient Thresholds in Three Aquatic Ecoregions of the Huntai River, Northeast China].

Benthic diatom communities and nutrient gradients were investigated from 287 sampling sites in three aquatic ecoregions (AE) of the Huntai River to characterize the spatial distribution of nutrients and the benthic diatom communities. Locally weighted scatterplot smoothing (LOWESS) was used to analyze the thresholds for nitrogen and phosphorus. The results showed that:① The concentration of ammonia nitrogen and total phosphorus significantly differs in the three AEs, and shows a tendency of AEⅠ < AE Ⅱ < AE Ⅲ.

[Impact of Talc Ore Mining on Periphyton Community Structure and Water Environment].

In order to explore the impact of Talc ore mining on aquatic ecosystems, periphyton communities and environmental factors from control portion, impacted portion and recovery portion separately were investigated and analyzed. Samples were collected from upstream Tanghe River (an important tributary of Tazi River) in November 2015, April 2016, and July 2016. Mann-Whitney U test was applied to compare the differences in environmental factors and periphyton community structures among three portions.

[Community Structure Characteristics of Eukaryotic Planktonic Algae in Liaohe River Through High-throughput Sequencing].

Eukaryotic phytoplankton plays an important ecological function in river ecosystem. The 18S rRNA gene V4 variable region of the environmental samples in Liaohe river was sequenced by using 454 pyrosequencing technology. The reprehensive sequences of OTUs were annotated, and then the OTUs list was compared to the species list obtained by microscope observation.

Evaluation of potential factors affecting deriving conductivity benchmark by utilizing weighting methods in Hun-Tai River Basin, Northeastern China.

Specific conductivity is an increasingly important stressor for freshwater ecosystems. Interacting with other environmental factors, it may lead to habitat degradation and biodiversity loss. However, it is still poorly understood how the effect of specific conductivity on freshwater organisms is confounded by other environmental factors.