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Electrochemical water splitting for hydrogen production is a promising solution for the production of renewable and environmentally friendly energy sources, but it is hindered by the sluggish kinetic process of oxygen evolution reaction (OER). Here, a novel hierarchical core-shell nanoarray NiCo/Ni/CuO/CF was synthesized by assembling Ni–Co hydroxide nanosheets directly on the metallic nickel coated CuO nanowires, as a highly efficient electrocatalyst for alkaline OER. This NiCo/Ni/CuO/CF anode exhibited low overpotentials of 246 mV and 286 mV at current densities of 10 mA cm−2 and 100 mA cm−2, respectively, and a small Tafel slope of 37.9 mV dec−1. Moreover, NiCo/Ni/CuO/CF showed robust durability at least 60 h at a current density of 100 mA cm−2. Detailed investigations verified that the unique nanosheets/nanowires architecture with high conductivity metallic nickel layer can expand the exposure of active sites and accelerate the transport of electrons. Image 1 • NiCo/Ni/CuO/CF electrode was prepared with CuO nanowires as supporting framework. • The nickel metal layer was employed to increase conductivity of the electrocatalyst. • Ni-Co electrode showed a low overpotential of 246 mV at 10 mA cm−2 towards OER. • NiCo/Ni/CuO/CF electrode exhibited robust durability under alkaline environment. [ABSTRACT FROM AUTHOR]

Mango is attracting increasing global attention for its superior flavor and nutritional benefits. However, the use of pesticides has resulted in a threat to its quality, safety, and human health due to their inevitable residue. There is an urgent need for advanced technologies that can efficiently and sensitively analyze a wide range of pesticides. In this study, a high-throughput screening and quantification method for 345 pesticides in mango was established by applying a modified QuEChERS method combined with liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF/MS). A response surface methodology (RSM) optimized the critical parameters for extracting various pesticides in 1% acetic acid-acetonitrile (v/v) using MgSO 4 , PSA, C 18 , and GCB as the adsorbents. The proposed method was successfully validated and applied to the quantitative detection of pesticide residues in 73 mango samples from Hainan. The study found pesticide residues in 95.9% of mango samples, of which 3 samples had residue concentrations in excess of the Chinese maximum residue limit. A total of 24 pesticides were detected, with detection percentages ranging from 1.4% (Thiabendazole) to 41.1% (Pyraclostrobin). Considering the possible health risks related to pesticide residues, risk assessment of human exposure to pesticides via intake of mango was evaluated. The acute and chronic dietary exposure risks related to pesticide residues in mango were accepted. In conclusion, this study provides a powerful platform for monitoring multiple pesticides in mango. First, it can promote the rational use of pesticides, and second, it can help consumers to assess the risk of dietary exposure to pesticide residues. [Display omitted] • QuEChERS based LC-Q-TOF/MS method was developed to detect 345 pesticides in mango. • The method showed satisfactory validation performance according to SANTE guideline. • The simplicity, high throughput, reliability of results were the advantage of method. • 95.9% of the mango samples were detected with one or several pesticide residues. • The chronic and acute risk assessment of mango from Hainan province were acceptable. [ABSTRACT FROM AUTHOR]

A new ionic liquid functionalized graphene-pipette-tip solid-phase extraction method coupled with high-performance liquid chromatography was established for the simultaneous extraction and determination of three auxins in soybean sprouts. The graphene adsorbent, with multiple adsorption mechanisms, was first synthesized by functional modification of pentafluorobenzyl imidazolium bromide ionic liquid through thiol-ene click chemistry. The ionic liquid was applied to prevent the aggregation of graphene; it also imbued graphene with the ability for π-π interactions, ionic exchange, electrostatic interactions, as well as hydrogen bonding (which is stronger than the interaction between water and analytes), by augmenting the adsorption mechanisms between the adsorbent and analytes. Under optimized conditions, linearity was achieved in the ranges 0.03–5.00 µg/g for indole-3-acetic acid and 1-naphthaleneacetic acid and 0.09–5.00 µg/g for 2,4-dichlorophenoxyacetic acid, with a detection limit of 0.004–0.026 µg/g; this adsorbent has been successfully applied for the determination of auxins in soybean sprouts. [ABSTRACT FROM AUTHOR]

Species of the genus Microcystis are among the most notorious cyanobacteria in eutrophic lakes worldwide, with ability present adverse effects on many aquatic organisms. In the surface sediments, Microcystis can be ingested by benthic macroinvertebrates such as Chironomus. However, the potential negative effects of Microcystis on Chironomus life history traits remain unclear. In the present study, we investigated the effect of different Microcystis diets on specific behaviors (burrowing activity, locomotion ability) and life history traits of Chironomus pallidivittatus (Diptera, Chironomidae). We also studied the interactive effects of microcystin-producing M. aeruginosa and temperature (15, 20, and 25 °C) stress on chironomid larvae. The results showed that the inhibitory effect on the cumulative emergence and burrowing activity of larvae was more severe when they were fed M. aeruginosa among the three Microcystis diets groups. Locomotion ability (i.e., locomotor distance and velocity) and adult dry weight decreased significantly in the group fed M. aeruginosa. Locomotion was significantly inhibited and mortality increased when the larvae were fed a mixture of M. aeruginosa and M. wesenbergii , which may have been the result of additive or synergistic effect of the toxins. Under the stress of lower temperature, C. pallidivittatus larvae exhibited weaker locomotion and growth ability, and the emerging adults were mostly male. At both the lower and higher temperature conditions, M. aeruginosa cause cumulative emergence decreased, and sex ratio imbalance, which inhibited the reproduction of larvae from the population perspective. The fourth-instar larvae showed better adaption to Microcystis than did the other instars. This study thus highlights the adverse effects of microcystin-producing M. aeruginosa on Chironomus. It also provides a novel perspective on how environmental factors may influence the behavior and life history traits of chironomid larvae, and how they may respond to cyanobacterial blooms and global warming. [Display omitted] • Emergence of adult and burrowing of larvae were inhibited when fed M. aeruginosa. • A mixture of Microcystis inhibited larval locomotion and increased mortality. • Fourth-instar larvae adapted relatively well to Microcystis stress at 15–25 °C. • Low temperature (15 °C) adversely affects larval behavior and development. [ABSTRACT FROM AUTHOR]

Cyanobacteria and their toxins present potential hazard to consumers of water from lakes, reservoirs and rivers, thus their removal via water treatment or at the source, is essential. Here, we report that alkyltrimethylammonium (ATMA) surfactants, such as octadecyltrimethylammonium (ODTMA) bromide, act as cyanocides that efficiently inhibit photosynthesis and growth of cyanobacteria. Green algae were found less sensitive than cyanobacteria to ATMA compounds. Fluorescence measurements and microscopic observations demonstrated that cyanobacteria cells (Aphanizomenon or Microcystis) disintegrate and lose their metabolic activity (photosynthesis) upon exposure to ATMA bromides (estimated ED 50(1hr) ranged between 1.5 and 7 μM for ODTMA-Br or hexadecyltrimethylammonium (HDTMA) bromide). Other ATMA compounds, such as tetradecyltrimethylammonium (TDTMA) or dodecyltrimethylammonium (DDTMA) bromides had similar inhibitory effect but their toxicity to cyanobacteria (measured as ED 50(1hr) for photosynthetic efficiency) decreased, as the length of the alkyl chain decreased. All ATMA compounds used in this study showed lower toxicity to green algae than to cyanobacteria. A toxicity mechanism for ATMA cations is proposed, based on real time fluorescence signals and on alteration of cell ultra-structure revealed by electron microscopy. The present study sheds light on the toxic effect of ATMA surfactants on cyanobacteria and its potential application for controlling the occurrence of cyanobacterial bloom in lakes, reservoirs or rivers to secure the safety of drinking water and to mitigate and manage bloom events. • Alkyltrimethylammonium (ATMA) surfactants inhibit photosynthesis. • Cyanobacteria show higher sensitivity to ATMA surfactants than green algae. • Toxicity of ATMA surfactants decreases with the shortening of the alkyl chain length. • Long chain ATMA surfactants can be used as effective and selective cyanocides. [ABSTRACT FROM AUTHOR]

• High cell concentration of Microcystis colonies promote surface scum formation. • Self-shading of Microcystis constitutes a positive feedback regulation of surface scum. • Larger and tighter colonies promote surface scum formation. • Small and loose colonies increase stability and persistence of surface scum. Light availability is an important driver of algal growth and for the formation of surface blooms. The formation of Microcystis surface scum decreases the transparency of the water column and influences the vertical distribution of light intensity. Only few studies analysed the interactions between the dynamics of surface blooms and the light distribution in the water column. Particularly the effect of light attenuation caused by Microcystis colonies (self-shading) on the formation of surface scum has not been explored. In the present study, we simulate the effect of variable cell concentration of Microcystis colonies on the vertical distribution of light in the water column based on experimental estimates of the extinction coefficient of Microcystis colonies. The laboratory observations indicated that higher cell concentration of Microcystis enhance the light attenuation in water column and promotes surface scum formation. We extended an existing model for the light-driven migration of Microcystis by introducing the effect of self-shading and simulated the dynamics of vertical migration for different cell concentrations and different colonial morphologies. The simulation results show that high cell concentrations of Microcystis promote surface scum formation, as well as its persistence throughout diel photoperiods. Large and tight Microcystis colonies facilitate scum formation, while small and loose colonies increase scum stability and persistence. This study reveals a positive feedback regulation of Microcystis surface scum formation and stability by self-shading and provides novel insights into the underlying mechanisms. [Display omitted] [ABSTRACT FROM AUTHOR]

• MIP allowed selective recognition of atrazine and its degradation products. • MIP were used in miniaturized SPE equipment to clean-up samples. • The proposed ASE-(MIP-PTSPE)-UPLC method can be applied to real samples detection. • This novel method was proved to be effective, simple and low cost. The Chinese Yam (Dioscorea opposita) is cultivated widely in China. However, there are potential safety risks associated with herbicide residues in Chinese Yam because of its characteristics and unregulated use of pesticides. We developed an efficient sample preparation technique for simultaneous analysis of atrazine and its degradation products in Chinese Yam using accelerated solvent extraction and pipette tip solid-phase extraction followed by UPLC-DAD analysis. Molecularly imprinted polymer (MIP) were used as the adsorbent material. Method performance was evaluated and our results showed the limit of quantification was 1–3 μg/ kg, with recoveries in the range 79.2–103.8%. When compared with other methods, this method provided superior performance in terms of sensitivity, accuracy, and precision. This method is, therefore, expected to be useful in supervised residue analysis. [ABSTRACT FROM AUTHOR]

• Strain IHB602 was identified and removed almost all inorganic nitrogen within 24 h. • Strian IHB602 presented biofilm formation properties. • Strian IHB602 showed better bioagumentation performance on biofilm-formation and nitrogen-removal in SBBR. A strain with efficient biofilm-formation and aerobic denitrification capabilities was isolated and identified as Pseudomonas mendocina IHB602. In pure culture, strain IHB602 removed almost all NO 3 −-N, NO 2 −-N, and NH 4 +-N (initial concentrations 50 mg/L) within 24 h. The strain produced large amounts of extracellular polymeric substances (maximum 430.33 mg/g cell dry weight) rich in protein but containing almost no humic acid. This, and strong autoaggregation (maximum 47.09%) and hydrophobicity (maximum 85.07%), imparted strain IHB602 with biofilm forming traits. A sequencing batch biofilm reactor bioaugmented with strain IHB602 (SBBR1) had more rapid biofilm-formation than the control without strain IHB602 inoculation (SBBR2). During the stabilization period, the effluent removal ratios for NH 4 +-N (95%), NO 3 −-N (91%) and TN (88%) in SBBR1 were significantly higher than those in SBBR2 (NH 4 +-N: 91%, NO 3 −-N: 88%, TN: 82%). Microbial community structure analysis revealed that strain IHB602 successfully proliferated and contributed to nitrogen removal as well as biofilm formation. [ABSTRACT FROM AUTHOR]

Cyanobacterial surface scum (here defined as visible Cyanobacteria colonies accumulating at the lake surface) is a harmful phenomenon that negatively affects water quality, human and animal health. Colony-forming Microcystis is one of the most important and ubiquitous genera that can suddenly accumulate at water surfaces. Turbulent water motion, e.g., generated by wind, can vertically disperse this scum layer, which later can re-establish by upward migration of Microcystis colonies. However, the role of wind-generated turbulence in scum formation and development is still poorly understood. Here we present results from a laboratory mesocosm study where we analysed the processes of scum formation and its response to wind-generated turbulence at low wind speed (≤3.6 m s−1). Microcystis colony size and flow velocity at the water surface and in the bulk water were measured using a microscope camera and particle tracking velocimetry. The surface scum formed by aggregation of colonies at the water surface, where they formed loose clusters of increasing size. The presence of large colony aggregations or of a surface film determined the stability of the scum layer. For the largest applied wind speed, most of the aggregations were broken down to sizes <2 mm, which were dispersed to the bulk water. The surface scum recovered quickly from such disturbances after the wind speed decreased. We further observed reduced momentum transfer from wind to water with the growing scum layer. The presence of the scum increased the threshold wind speed for the onset of flow and reduced the flow velocities that were generated above that threshold. This effect was likely caused by the presence of a film of surface-active material at the water surface (surface microlayer), which is related to the presence of Microcystis. Both the small-scale turbulence and surface microlayer might play an important, yet largely unexplored role in Microcystis surface scum development in aquatic ecosystems. Improved understanding of the interplay of both processes will be instrumental for improving current mechanistic models for predicting surface bloom dynamics. Image 1 • First laboratory observations of interactions between Microcystis scum and wind. • Colony aggregation facilitated by the viscous sublayer at the water surface. • Strong reduction of momentum transfer from wind to water by surface scum. [ABSTRACT FROM AUTHOR]

Global climate change as well as human activities have been reported to increase the frequency and severity of both salinization and harmful algal blooms (HABs) in many freshwater systems, but their co-effect on benthic invertebrates has rarely been studied. This study simultaneously examined the joint toxicity of salinity and different cyanobacterial diets on the behavior, development, select biomarkers, and partial life cycle of Chironomus pallidivittatus (Diptera). High concentrations of salts (e.g., 1 g/L Ca2+ and Mg2+) and toxic Microcystis had synergistic toxicity , inhibiting development, burrowing ability and causing high mortality of C. pallidivittatus , especially for the Mg2+ treatment, which caused around 90% death. Low Ca2+ concentration (e.g., 0.01 g/L) promoted larval burrowing ability and inhibited toxin accumulation, which increased the tolerance of Chironomus to toxic Microcystis. However, low Mg2+ concentration (e.g., 0.01 g/L) was shown to inhibit the behavior, development and increase algal toxicity to Chironomus. Toxic Microcystis resulted in microcystin (MC) accumulation, inhibited the burrowing ability of larvae, and increased the proportion of male adults (>50%). The combined toxicity level from low to high was verified by the weight of evidence and the grey TOPSIS model, which integrated five lines of evidence to increase the risk assessment accuracy and efficiency. This is the first study that provided insights into ecological risk arising from the joint effect of salinity and harmful algae on benthic organisms. We suggest that freshwater salinization and HABs should be considered together when assessing ecological threats that arise from external stress. [Display omitted] • Joint toxic assessment was evaluated by weight of evidence and grey TOPSIS model. • Low Ca2+ concentration (0.01 g/L) promoted larva tolerance level to harmful algae. • Low concentration of Mg2+ can increase the algae toxicity to Chironomus than Ca2+. • High salts levels (1 g/L) inhibited larva development and caused higher mortality. • Higher MC accumulation can lead to higher male adult ratio in benthic Chironomus. [ABSTRACT FROM AUTHOR]

• LISST can well applied to monitor the mean cell size and colony size of cyanoHABs. • Cell density of algae can be estimated reliably based on total and mean cell biovolume. • The protocol for in-situ tracking migration of cyanoHABs was validated in the tank. • The 3D section views of cyanoHABs in Dianchi lake were well obtained by LISST-HAB. Cyanobacterial harmful algal blooms (cyanoHABs) are becoming increasingly common in aquatic ecosystems worldwide. However, their heterogeneous distributions make it difficult to accurately estimate the total algae biomass and forecast the occurrence of surface cyanoHABs by using traditional monitoring methods. Although various optical instruments and remote sensing methods have been employed to monitor the dynamics of cyanoHABs at the water surface (i.e., bloom area, chlorophyll a), there is no effective in-situ methodology to monitor the dynamic change of cell density and integrated biovolume of algae throughout the water column. In this study, we propose a quantitative protocol for simultaneously measurements of multiple indicators (i.e., biovolume concentration, size distribution, cell density, and column-integrated biovolume) of cyanoHABs in water bodies by using the laser in-situ scattering and transmissometry (LISST) instrument. The accuracy of measurements of the biovolume and colony size of algae was evaluated and exceeded 95% when the water bloom was dominated by cyanobacteria. Furthermore, the cell density of cyanobacteria was well estimated based on total biovolume and mean cell volume measured by the instrument. Therefore, this methodology has the potential to be used for broader applications, not only to monitor the spatial and temporal distribution of algal biovolume concentration but also monitor the vertical distribution of cell density, biomass and their relationship with size distribution patterns. This provides new technical means for the monitoring and analysis of algae migration and early warning of the formation of cyanoHABs in lakes and reservoirs. [Display omitted] [ABSTRACT FROM AUTHOR]

• Strain DC-1 was identified and removed 98.4% NO 3 –-N and 80.7% TOC under aerobic condition. • Strian DC-1 showed complete nitrogen removal pathway. • Strian DC-1 owed zero N 2 O-emitting and high auto-aggregation properties. A novel aerobic denitrifying strain Methylobacterium gregans DC-1 was isolated and identified. Strain DC-1 removed 98.4% of nitrate-nitrogen (NO 3 −-N) and 80.7% of total organic carbon with initial concentrations of 50 and 2400 mg/l, respectively. The N balance showed that most NO 3 −-N was converted to N 2 (62.18%) without nitrous oxide (N 2 O) emission. Response surface analysis showed that the optimal conditions for total N removal were carbon (C):N ratio of 18.7, temperature of 26.8 °C, pH of 6.5 and shaking speed of 180 rpm. In combination with the N balance and successful amplification of napA , nirK and nosZ genes, the metabolic pathway was as follows: NO 3 −NO 2 − → NO → N 2 O → N 2. Strain DC-1 had strong auto-aggregation rate (maximum 38.7%), produced large amounts of extracellular polymeric substances (EPS; maximum of 781.4 mg/g cell dry weight) and had corresponding strong hydrophobicity (maximum 83.2%). Pearson correlation analysis showed that EPS content and hydrophobicity were significantly positively correlated with auto-aggregation. [ABSTRACT FROM AUTHOR]

[Display omitted] • An instant and reversible flocculation method was developed for microalgae harvest. • Complexation of CTS and XG deduced the formation of centimeter-sized flocs. • Flocs were formed within 20 s and could resist strong hydraulic shear. • Harvesting efficiency exceeded 95% when filtered with 500-μm-pore-sized sieves. • CTS and XG could be recovered and reused by the adjustment of pH or salinity. An instantaneous and reversible flocculation method for Scenedesmus harvesting was developed, based on the complexation of Chitosan (CTS) and Xanthan Gum (XG). Under rapid stirring, Scenedesmus cells formed centimeter-sized flocs within 20 s using binary flocculants of 4 mg/L CTS and 16 mg/L XG. These flocs exhibited a remarkable harvest efficiency exceeding 95 % when filtered through 500-μm-pore-sized sieves. Furthermore, the flocs could be completely disintegrated by using alkaline or NaCl solutions (pH > 11 or NaCl concentration > 1.5 mol/L). Adjusting pH allowed recovery of 50 % CTS and 75 % XG, resulting in microalgae biomass with lower flocculant content and reducing reagent costs. Electrostatic interaction of –COO– of XG and –NH 3 + of CTS deduced the formation of polyelectrolyte complexes (PECs), which shrink and wrap the coexisting algal cells to form the flocs under stirring. CTS and XG complexation was instantaneous and reversible, explaining quick flocculation and disintegration. [ABSTRACT FROM AUTHOR]

• Low light intensity can promote the persistent floatation of microcystis colony. • High light intensity can induce high growth rate and large size of colonies. • Loose and large colonies can easy sink after a long term exposure to high light. • Light attenuation inside colonies restricts the maximal colony size. Light is an important driver of algal growth and for the formation of surface blooms. Long-term buoyancy maintenance of Microcystis colonies is crucial for their aggregation at the water surface and the following algal bloom development. However, the effect of light-mediated variations of colony morphology on the buoyancy regulation of Microcystis colonies remains unclear. In this study, growth parameters, colony morphology and floatation/sinking performance of Microcystis colonies were determined to explore how variations in colony morphology influence the buoyancy of colonies under different light conditions. We quantified colony compactness through the cell volume to colony volume ratio (VR) and found different responses of colony size and VR under different light intensities. Microcystis colonies with higher VR could stay longer at the water surface under low light conditions, which was beneficial for the long-term growth and buoyancy maintenance. However, increased colony size and decreased compactness were observed at a later growth stage under relatively higher light intensity (i.e., >108 µmol photons m−2 s−1). Interestingly, we found a counterintuitive negative correlation between colony size and buoyancy of Microcystis under high light intensity. Additionally, we found that the influence of colony morphology on buoyancy was stronger at high light intensity. These results indicate that light could regulate the buoyancy via colonial morphology and that the role of colony morphology in buoyancy regulation needs to be accounted for in further studies under variable environmental conditions. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Aerobic biodegradation has been considered to be the main attenuation mechanism for microcystins, but the role of anoxic biodegradation remains unclear. We investigated the potential for anoxic biodegradation of microcystin and the effects of environmental factors on the process through a series of well-controlled microcosm experiments using lake sediments as inocula. Microcystin LR could be degraded anoxically from 5mgL−1 to below the detection limit at 25°C within 2 days after a lag phase of 2 days. The rate was highly dependent on temperature, with a favorable temperature range of 20–30°C. The addition of glucose or low levels of NH4-N had no effect on the anoxic biodegradation of microcystin, whereas the addition of NO3-N significantly inhibited the biodegradation at all experimental concentrations, and the inhibition increased with increasing amount of NO3-N-amended. Adda (3-amino-9-methoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid), a previously reported nontoxic product of aerobic degradation of microcystin, was identified as the anoxic biodegradation product. This is the first report of Adda as a degradation product of microcystin under anoxic conditions. No other product containing Adda residue was detected during the anoxic degradation of microcystin. These results strongly indicated that anoxic biodegradation is an effective removal pathway of microcystin in lake sediments, and represents a significant bioremediation potential. [Copyright &y& Elsevier]

• The bioaugmentation-assisted coaggregation was a suitable treatment strategy. • Three aerobic denitrifiers together showed optimal coaggregation trait. • Coaggregation strains colonized successfully in biofilm system. • Applying coaggregation strains improve nitrogen-removal and biofilm-formation. To promote efficiency nitrogen-rich wastewater treatment from a sequencing batch biofilm reactor (SBBR), three aerobic denitrifiers (Pseudomonas mendocina IHB602, Methylobacterium gregans DC-1 and Pseudomonas stutzeri IHB618) with dual-capacities of strong auto-aggregation and high nitrogen removal efficiency were studied. The aggregation index analysis indicated that coaggregation of the three strains co-existed was better when compared with one or two strains grown alone. Optimal coaggregation strains were used to bioaugmente a test reactor (SBBR T), which exhibited a shorter time for biofilm-formation than uninoculated control reactor (SBBR C). With different influent ammonia-N loads (150, 200 and 300 mg·L-1), the average ammonia-N and nitrate-N removal efficiency were all higher than that in SBBR C , as well as a lower nitrite-N accumulation. Microbial community structure analysis revealed coaggregation strains may successfully colonize in the bioreactor and be very tolerant of high nitrogen concentrations, and contribute to the high efficiency of inorganic nitrogen-removal and biofilm-formation. [ABSTRACT FROM AUTHOR]

Cyanobacterial blooms are a major problem in many lakes and can negatively impact public health and ecosystem services. The bioflocculation technique has proven to be a cost-effective, environmentally friendly technique with no secondary pollution to harvest multiple microalgae; however, few studies have focused on its effect on and potential for controlling cyanobacterial blooms in eutrophic lakes. In this study, the bioflocculation efficiencies of different Microcystis species under Glyptotendipes tokunagai (Diptera, Chironomidae) stress conditions and the interactions between secreted silk from Chironomid larvae and extracellular polymeric substances (EPS) from Microcystis were compared. The results indicated that G. tokunagai presented better bioflocculation efficiency on M. wesenbergii than on M. aeruginosa. The formation of "Large Algal Aggregate" flocs was promoted by the derived-soluble extracellular polymeric substances (i.e., proteins and polysaccharides, sEPS) from M. wesenbergii and silk from G. tokunagai. Both M. wesenbergii and midge silk had abundant functional groups, which was beneficial to the formation of the large aggregate. G. tokunagai secreted a large amount of silk to bridge with the sEPS of M. wesenbergii , forming a network structure via interaction between filamentous substance (i.e., complex of sEPS and silk) that plays an important role in the aggregation of Microcystis and the removal of the Microcystis biomass in the water column. The findings provide further insights that will benefit the existing efforts of combating Microcystis blooms in the water column via bioflocculation and will provide a new sustainable approach for inhibiting early bloom formation from the perspective of its provenance in the sediment-water interface. [Display omitted] • G. tokunagai exhibited better bioflocculation efficiency on M. wesenbergii. • Midge silk plays an important role in the aggregation of Microcystis via adhesion. • M. wesenbergii EPS contributed to the formation of the "Large Algal Aggregate". • The silk bridge with the EPS forms a network structure to adhere to Microcystis. [ABSTRACT FROM AUTHOR]