Sulfide inhibition on polyphosphate accumulating organisms and glycogen accumulating organisms: Cumulative inhibitory effect and recoverability.

Sulfate in wastewater can be reduced to sulfide and its impact on the stability of enhanced biological phosphorus removal (EBPR) is still unclear. In this study, the metabolic changes and subsequent recovery of polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) were investigated at different sulfide concentrations. The results showed that the metabolic activity of PAOs and GAOs was mainly related to H2S concentration. Under anaerobic conditions, the catabolism of PAOs and GAOs was promoted at H2S concentrations below 79 mg/L S and 271 mg/L S, respectively, and inhibited above these concentrations; whereas anabolism was consistently inhibited in the presence of H2S. The phosphorus (P) release was also pH-dependent due to the intracellular free Mg2+ efflux from PAOs. H2S was more destructive to the esterase activity and membrane permeability of PAOs than those of GAOs and prompted intracellular free Mg2+ efflux of PAOs, resulting in worse aerobic metabolism and subsequent recovery of PAOs than GAOs. Additionally, sulfides facilitated the production of extracellular polymeric substances (EPS), especially tightly bound EPS. The amount of EPS in GAOs was significantly higher than that in PAOs. The above results indicated that sulfide had a stronger inhibition to PAOs than GAOs, and when sulfide was present, GAOs had a competitive advantage over PAOs in EBPR.

Development of methods for quantitative determination of the total and reactive polysulfides: Reactive polysulfide profiling in vegetables.

Alliaceous and cruciferous vegetables are rich in bioactive organosulfur compounds, including polysulfides, which exhibit a broad spectrum of potential health benefits. Here, we developed novel, accurate, and reproducible methods to quantify the total polysulfide content (TPsC) and the reactive polysulfide content (RPsC) using liquid chromatography-electrospray ionization-tandem mass spectrometry, and analyzed the reactive polysulfide profiles of 22 types of fresh vegetables, including onions, garlic, and broccoli. Quantitative analyses revealed that onions contained the largest amounts of polysulfides, followed by broccoli, Chinese chive, and garlic. A strong positive correlation was observed between the TPsC and RPsC, whereas only a moderate positive correlation was found between the total sulfur content and TPsC. These results suggest that reactive polysulfide profiling can be a novel criterion for evaluating the beneficial functions of vegetables and their derivatives, which may lead to an understanding of the detailed mechanisms underlying their bioactivities.

Assessing the enhanced reduction effect with the addition of sulfate based P inactivating material during algal bloom sedimentation.

The typical harm effect of algal bloom sedimentation is to increase sulfides level in surroundings, threatening aquatic organisms and human health; whereas, P inactivating materials containing sulfate are commonly attempted to be used to immobilize reactive P or to flocculate excessive algae in water columns for eutrophication control. In this study, variations in sulfate reduction during algal bloom sedimentation with the addition of sulfate based inactivating materials was comprehensively assessed based on using Al2(SO4)3 with comparison to AlCl3. The results showed that addition of Al2(SO4)3 had more substantial effect on overlying water and sediment properties compared to those of ACl3. Al2(SO4)3 can enhance sulfate reduction, resulting in temporary increase of sulfides (p < 0.01) and quick decrease of various Fe (p < 0.01) in overlying water and then promoting the formation of FeS and FeS2 (determined by EXAFS analysis) in sediments. Most importantly, the increased sulfides, as well as the physical barrier on sediment formed due to Al2(SO4)3 addition, enhanced the transformation of sulfides to odorous contaminants, increasing odorous contaminants (especially methyl thiols) production by approximately one order of magnitude in overlying water. Furthermore, the increased sulfides facilitated to the enrichment of microorganisms related to S cycles (Thiobacillu with relative abundance of 23.8%) and even promoted to enrich bacterial genus potentially with pathogenicity (Treponema) in sediments. The impacts of sulfate tended to be regulated by algae concentration; however, careful management was recommended for sulfate based inactivating materials application to control eutrophication with algal blooms.

Unravelling in-situ hardpan properties and functions in capping sulfidic Cu-Pb-Zn tailings and forming a duplex soil system cover.

Developing alternative approaches to cap and rehabilitate the large areas of tailings landscapes is critical for sustainable development of mining industry. This study revealed the potential of an in-situ hardpan-based duplex soil system as an un-conventional approach to rehabilitate sulfidic Cu-Pb-Zn tailings. Under a shallow silicious soil cover, a massive and consistent hardpan horizon had been formed in-situ at the surface layer of tailings across the trial area, which physically separated root zones (i.e., silica soil cover) from the un-weathered tailings underneath, prevented capillary enrichment of acidity and soluble solutes into the root zones, and sustained native plant growth for more than a decade. Precipitation of Si-rich ferric complexes were attributed to the stabilisation/solidification of the sulfidic tailing. The hardpan layer possesses a highly compacted texture, a low-percolating pore network, and extreme resistance to water movement in the hardpan horizon. Further, the hardpans directly interfacing with plant roots in the soil cover were geochemically stabilised and attenuated, with very low levels of soluble metal(loid)s and a circumneutral pH condition. This case study would serve as a good incentive to develop bio-chemical engineering methodology building on current knowledge for achieving sustainable rehabilitation of sulfidic and metallic tailings in future.

Enhancing the retention of phosphorus through bacterial oxidation of iron or sulfide in the eutrophic sediments of Lake Taihu.

Microbial activity can enhance the sequestration of phosphorus (P) in sediments, but little is known about the mechanisms behind it. In this study, sediment cores were sampled from the most eutrophic Meiliang Bay of Lake Taihu, and three treatments were set up in a laboratory incubation experiment, involving (a) the non-treated sediment cores, (b) inoculation, and (c) sterilization. The dissolved and labile iron (Fe) and P were obtained by high-resolution dialysis and the diffusive gradients in thin films (DGT) technique, respectively. AgI-based DGT was used for measuring the 2D distribution of labile sulfide. The bacterial community was investigated using a scanning electron microscope and 16S rRNA high throughput sequencing technique. The results showed that sterilization reduced the capacity of sediment to immobilize P, and that the critical sediment depth layer for microbial P sequestration was 0-10 mm. In addition, sterilization or inoculation significantly changes the structure of bacterial communities. Fe or S oxidation under micro-aerobic or anaerobic conditions played an important role in bacterial retention of P in the sediments. Nitrate-reducing coupling Fe(II)-oxidizing bacteria (Acidovorax) in the inoculated sediment and electrogenic sulfur-oxidizing bacteria (Candidatus Electronema) in the non-treated sediment were identified as the key bacterial genera responsible for the retention of P in sediments. This implies that bacterial communities could quickly establish the ability for negative feedback regulation by inoculation once the function and structure of indigenous sediment bacteria are seriously impaired, although this needs further validation in the field.

In vitro and In vivo toxicity analysis of zinc selenium/zinc sulfide (ZnSe/ZnS) quantum dots.

Despite the versatility of quantum dots (QDs) in optoelectronics and biomedical field, their toxicity risks remain a considerable hindrance for clinical applications. Cytotoxicity of Cadmium containing QDs is well documented and reveals that they are toxic to cells. Reports suggest that the presence of toxic elements at the QD core (e.g., cadmium, selenium) is responsible for its toxicity in in vivo and in vitro levels. Hence, here the toxicity of heavy metal free ZnSe/ZnS QDs on two scenarios were assessed, (i) HEK cells as in vitro system and (ii) Swiss Albino mice as in vivo model. Before toxicity analysis, QDs subjected to various optical and physico-chemical characterization methods such as absorption and emission spectra analysis, observation under U.V light, TEM, DLS, Zeta potential, FTIR, Raman and XPS spectra, ICP-OES, TGA and DTG curve. It is very necessary to characterize the synthesized QDs because their toxicity greatly influenced by the physico-chemical properties. On checking the vulnerability of HEK cells on exposure to ZnSe/ZnS QDs, the obtained results disclose that ZnSe/ZnS QDs showed merest impact on cellular viability at a concentration less than 100 µg/ml. Acute toxicity of 10 mg/kg ZnSe/ZnS QDs was studied in mice and no clinical or behavioural changes were observed. It did not induce any changes in haematological parameters and any loss of body or organ weight. Moderate pathological changes were evident only in the liver, all others organs like kidney, spleen and brain did not show any manifestations of toxicity. Current work lays substantial bedrock for safe biomedical and environmental application of ZnSe/ZnS QDs in near future.

Selenium Enrichment in Pore Water of Estuarine Sediments Subject to Salt Marsh Vegetation Bioirrigation (Patos Estuary, Southern Brazil).

Selenium (Se), iron (Fe), and free sulfides contents in pore waters were measured to study the liberation of soluble Se in suboxic conditions. The sediment core was collected in a salt marsh in Patos Lagoon estuary (southern Brazil), and it was obtained during a brackish water period, in a low intertidal stand vegetated by Spartina alterniflora. The redox potential (Eh), pH, andacid volatile sulfides (AVS) content were also investigated. Pore water results sustained the idea that S. alterniflora roots promote oxygen penetration to depths of ca. 10 cm below the salt marsh surface, increasing Eh and lowering the pH in this interval. High Se concentrations (e.g., 16.9 µg L-1), that are above US. EPA environmental criteria, were observed in the pore water to depths between 10 and 20 cm and are associated to low AVS contents and high concentrations of free sulfides. In the first 10 cm the lowering of Se contents probably happens due the low pH and biological volatilization of the metalloid.

A comparative analysis of the essential oils from two species of garlic seedlings cultivated in China: chemical profile and anticoagulant potential.

Garlic seedlings (GS) and blanched garlic seedlings (BGS) are two kinds of common garlic-derived vegetables in China, but little information is available on their bioactive constituents. In this work, chemical profiles and anticoagulant activities of essential oils from GS (EOGS) and BGS (EOBGS) were disclosed and compared for the first time. Sixteen and fourteen volatile compounds were identified in EOGS and EOBGS by GC-MS analysis, and both of them were rich in sulfur-containing compounds, particularly diallyl sulfides accounting for 74.77% and 85.87%, respectively. EOGS and EOBGS exerted anticoagulant activities via intrinsic, extrinsic, and common coagulation pathways as well as by lowering the content of fibrinogen; EOGS exceeded EOBGS in the activation of intrinsic and extrinsic coagulation pathways, while EOBGS outperformed EOGS on the activation of the common coagulation pathway, which was even superior to that of heparin at the same dose. Herein, the results of the present investigation will give a strong clue that EOGS and EOBGS are more likely to lead to a promising way to vegetable-based anticoagulants.

Incorporation of nanoencapsulated garlic essential oil into edible films: A novel approach for extending shelf life of vacuum-packed sausages.

The efficacy of chitosan (CH) and whey protein (WP) films impregnated with garlic essential oil (GEO, 2% v/v) or nanoencapsulated GEO (NGEO, 2% v/v) to extend the shelf life of refrigerated vacuum-packed sausages were assessed and compared during 50 days. The primary evaluation of GEO and NGEO showed that GEO had a considerable amount of active compounds diallyl sulfide derivatives (~67%) and the mean size and zeta potential of NGEO were 101 nm and -7.27 mV, respectively. Based on the microbiological and lipid stability analysis of the sausages, all active films retarded lipid oxidation and the growth of main spoilage bacterial groups compared to the control, and CH film containing NGEO exhibited the best result with the peroxide value, thiobarbituric acid reactive substances and aerobic plate count of 0.37 (meq/kg lipid), 0.47 (mg malondialdehyde/kg) and 3.69 (log CFU/g), respectively, on day 50. The nanoencapsulation of GEO made no significant differences in the sensory properties comparing to free-GEO samples (P < .05).

Controlled-synthesis of alumina-graphene oxide nanocomposite coupled with DNA/ sulfide fluorophore for eco-friendly "Turn off/on" H2S nanobiosensor.

Hydrogen sulfide (H2S) is a toxic environmental pollutant and crucial gas-signaling agent of human physiology. There is an urgent need for developing a sensitive and selective detection approach for H2S. Herein, a novel turn off/on response approach using γ-Al2O3 nanorods anchored on the surface graphene oxide (GO) nanosheets and coupled with DNA/sulfide fluorophore (SF) for H2S detection at room temperature was developed. The fluorescent fluorophore, DNA/SF, remains quenched on the super quencher γ-Al2O3-GO hybrid surface. In the existence of H2S, DNA/SF fluorophore was detached from γ-Al2O3-GO hybrid surface because of the strong physical adsorption interaction between H2S molecules and γ-Al2O3-GO surface. The recovered fluorescence intensity gave direct insight about H2S concentration in the medium. The developed γ-Al2O3-GO/DNA/SF nanobiosensor shows high sensitivity with 75 to 2.5 µM linear detection range of H2S, and a high binding constant of 9.8 × 103 M-1. The nanobiosensor is very selective toward H2S in the presence of various interfering anions and thiols and used for H2S detection in real water samples. γ-Al2O3-GO/DNA/SF nanobiosensor provides a cheap, simple, and highly selective H2S detection method at room temperature.

Methanethiol, an Off-Flavor Produced from the Thermal Treatment of Mandarin Juices: A Study of Citrus Sulfur Volatiles.

The off-flavor produced after thermal stabilization of mandarin (Citrus reticulata, Blanco) juices has limited the production of commercial juices. Methanethiol, a putrid-smelling sulfur volatile, has been identified for the first time in heated mandarin juices. Identification was achieved using a combination of capillary gas chromatography with two dissimilar columns and a dual sulfur-specific pulsed flame photometric detector and selected ion mass spectrometry detection. Static headspace solid-phase microextraction quantitation found that average odor activity values (OAVs) in heated juices were 25.5 for methanethiol compared to 10.8 for dimethyl sulfide. OAVs for methanethiol and dimethyl sulfide in fresh juices were ND (not detected) and 5.5, respectively. Hydrogen sulfide, carbonyl sulfide, carbon disulfide, and dimethyl disulfide were also identified and quantitated. Thermal decomposition studies of nonvolatile sulfur-containing potential precursors indicated that methionine was the major source of methanethiol. Additional heating studies with model juices demonstrated that ascorbic acid greatly accelerated the formation of methanethiol and methional, as well as dimethyl di and tri sulfides.

Indirect determination of mercury(II) by using magnetic nanoparticles, CdS quantum dots and mercury(II)-binding aptamers, and quantitation of released CdS by graphite furnace AAS.

This work describes an aptamer based method for highly sensitive determination of Hg(II). A Hg(II)-binding ssDNA aptamer was linked to silica-coated magnetic nanoparticles (magNPs). Then, a conjugate composed of graphene and CdS quantum dots (Gr-CdS) was linked to the complementary ssDNA. On mixing the two components, a duplex of type magNP-dsNNA-Gr/CdS is generated. If Hg(II) is added, it wills capturing the aptamer, and this leads to the release of Gr/CdS because of the formation of a stable thymine-Hg2+-thymine link. External magnetic force is used to remove the remaining complex. The released graphene-CdS is decomposed by HNO3 and injected into a graphite furnace AAS. The detectable amount of Cd is proportional to the concentration of Hg(II) in the sample. Under the optimal conditions, the method has a linear response in the 2.50 aM to 0.25 nM Hg(II) concentration range, and the detection limit is as low as 7.6 aM (at S/N = 3). It has high selectivity for Hg(II) over other metal ions. Graphical abstract.

Influence of Different Frying Processes on the Flavor Characteristics and Sensory Profile of Garlic Oil.

Fried garlic oil has been widely used in traditional Chinese cuisine and, recently, has become increasingly popular in food manufacturing. In this study, the effects of different initial and final frying temperature on the flavor characteristics and sensory profile of fried garlic oil were investigated using solvent-assisted flavor evaporation (SAFE) combined with gas chromatography-mass spectrometry (GC-MS). Results showed that the content of flavor compounds changed significantly as the frying temperature was increased. The sample that was treated at an initial temperature of 115 °C and a final temperature of 155 °C contained the highest amount of thioethers and heterocycles, mainly comprising dimethyl trisulfide, diallyl disulfide, and 2-vinyl-4H-1,2-dithiin. Partial least-squares regression elucidated the sensory attributes of fried and roasted garlic, showing a high correlation with thioethers and pyrazines. Furthermore, changes in the 2,6-dimethylpyrazine, dimethyl trisulfide, and diallyl disulfide concentrations were detected every 5 °C during the frying process (initial temperature, 115 °C; final temperature, 155 °C). Dimethyl trisulfide and diallyl disulfide concentrations showed irregular, downward trends, while 2,6-dimethylpyrazine concentration exhibited an increasing trend.

[Formation and extent of peloid deposits in the Caspian Plain]. / Formirovanie i rasprostranenie mestorozhdenii lechebnykh griazei v Prikaspiiskoi nizmennosti.

Main mud resources of brine lakes for balneological purpose form and accumulate in the zone of steppes and semi-deserts in the south and south-east of Russia (for example, in the Caspian Lowland). The main genetic types of peloids in the zone of steppes and semi-deserts are: 1) sulfide silt muds; 2) sapropels; 3) freshwater clayey silts. Sulphide silt muds form in the areal extent of salt-dome tectonics of the Caspian Lowland. According to the salt ionic composition of slush, the peloids of the lakes of the Caspian Lowland are sodium chloride, magnesium, magnesium-sodium; sulphate-chloride magnesium-sodium (less often sodium); the sodium bicarbonate chloride peloids are less common. Slush mineralization varies between 73 and 328 g/dm3. The deposits of the Inder, Botkul, Elton, and Baskunchak Lakes and a number of shors are an example of highly mineralized sulfide muds. Black muds are oily to the touch. The silt deposits of lakes and shors are those of (bromine) salt saturated peloids - from weakly sulfide to strongly sulfide. They belong to promising or unpromising deposits due to the low power of the layers. The balneological resources of lakes, mud, and brine are a multipurpose product and can be comprehensively used in the national economy and in the improvement of the population's health.

Distribution character of localized iron microniche in lake sediment microzone revealed by chemical image.

DGT (diffusive gradients in thin films) technique and LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) for heterogeneous distribution of the soluble labile iron (Fe) at submillimeter resolution in lake sediment porewater are reported. The soluble labile Fe species include ion and labile organic complexes. The chemical images in two dimensions (2D) for DGT concentration of Fe (CDGT(Fe)) are investigated for Fe remobilization character. There are 902 CDGT(Fe) values between 1000 and 2000 µg L-1, 463 values between 2000 and 3000 µg L-1, and 112 values over 3000 µg L-1 in all chemical maps. Based on the linear correlation relationships between CDGT (Fe) and total Fe (TFe), total organic carbon (TOC), acid-volatile sulfide (AVS), Eh, concentrations of the soluble reactive phosphorus (P) (SRP), and soluble labile trace metals (Zn, Cu, Pb, and Zn) in a vertical 1D profile of sediment or porewater, Fe release mechanisms are mainly due to the reductive Fe release from iron oxyhydroxides and the decomposition of organic matter in algae biomass and deep sediment layer. It can be used to explain the formation mechanisms of Fe microniches in chemical maps with heterogeneous character to a great extent. CDGT(Fe) peak flux in the center of Fe microniche and the low CDGT (Fe) at the edge of a microniche are due to the formation of the insoluble iron sulfide and the abundant acid-volatile sulfide (AVS) in sediment. The verified co-remobilization of the soluble labile Fe and trace metals or SRP in sediment porewater can be used to predict their simultaneous release from Fe microniches with the large CDGT (Fe) peaks. The different kinds of Fe microniche zones and hot spots from sediment/water interface (SWI) to deep sediment correspond to the formation mechanisms of microniches mentioned above. Moreover, some narrow Fe microniche zones with the large CDGT (Fe) across chemical maps are due to the desorption of Fe(II) from the freshly formed oxide on Myriophyllum verticiilatur roots, which are located at sites of microniche zones.

Redox-dependent phosphorus burial and regeneration in an offshore sulfidic sediment core in North Yellow Sea, China.

Phosphorus (P) pollution can trigger severe marine eutrophication, which further leads to harmful algal blooms, and a deterioration of sea water quality. The P burial and regeneration in offshore sediments can directly affect the eutrophication levels of estuarine and coastal ecosystems. Although many researches on redox-dependent P burial and regeneration were studied, such process in the presence of silicate is still poorly understood, and the effects of pyrite formation on organic P (OP) burial and regeneration also remain unclear. In this study, a sulfidic sediment core was collected in the offshore of an estuary in the north Yellow Sea, China. Results indicated that indigenous biological input was found to be the primary source of organic matter in upper sediments. The regenerated P under reducing conditions was dominated by labile FeP and OP. The PO43- released from FeP and OP that could be captured by Al/Fe/Mn (oxyhydr) oxides in surface sediments and Ca minerals in deep sediments. CaP, AlP, unreactive Al/Fe-Si-P and some stable metal chelated OP were the main burial P fractions. Sulfate reduction and formation of insoluble metal sulfides including the pyrite promoted OP decomposition by anaerobic decomposition, removing metal ions from the "metal-OP" chelates and restoring the phosphatase activity.

Diagenesis of sulfur, iron and phosphorus in sediments of an urban bay impacted by multiple anthropogenic perturbations.

Solid-phase speciation and porewater chemistry measured by the diffusive gradients in thin films (DGT) technique were used to understand the diagenesis of sulfur (S), iron (Fe), and phosphorus (P) in sediments of Jiaozhou Bay (China), which has been impacted by multiple anthropogenic perturbations. Despite water eutrophication, sediments of the bay are low in organic carbon and sulfide, but high in unsulfidized Fe(II). Dissimilatory iron reduction (DIR) prevails in sediments of the bay, and there is no evidence for responses of S and Fe diagenesis to the water eutrophication, which is largely attributable to unique depositional and diagenetic regimes in association with multiple anthropogenic perturbations. Good coupling of porewater Fe2+ and P in the porewaters suggests that P mobilization is driven mainly by DIR. Low Fe2+/P ratios in porewaters imply that oxidative regeneration of Fe oxides within the upper sediments is incapable of efficiently scavenging upward diffusing P.

Separation of Uranium and Thorium for 230Th-U Dating of Submarine Hydrothermal Sulfides.

The age of a submarine hydrothermal sulfide is a significant index for estimating the size of hydrothermal ore deposits. Uranium and thorium isotopes in the samples can be separated for 230Th-U dating. This article presents a method to purify and separate U and Th isotopes in submarine hydrothermal sulfide samples. Following this technique, the separated U and Th fractions can meet measuring requirements by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The age of the hydrothermal sulfide sample can be calculated by measuring the present-day activity ratios of 230Th/238U and 234U/238U. A super clean room is necessary for this experiment. Cleaned regents and supplies are used to reduce the contamination during the sample processes. Balance, hotplate, and centrifuge are also used. The sulfide sample is powdered for analysis and less than 0.2 g sample is used. Briefly, the sample is weighed, dissolved, added to 229Th-233U-236U double spike solution, Fe co-precipitated, and separated on an anion-exchange resin extraction column. Approximately 50 ng U is consumed for 230Th-U dating of sulfides sample by MC-ICPMS.

Fatal acute arsenic poisoning by external use of realgar: Case report and 30 years literature retrospective study in China.

Realgar (arsenic sulfide) is widely used in combination with other herbs as Chinese patent medicine to treat a variety of diseases in China. As a mineral arsenic, its mild toxicity was also well known. Longtime over-dose usage or wrongly oral intake of realgar can cause chronic arsenic poisoning and/or death, but acute fatal arsenic poisoning resulted from short-term dermal use of realgar-containing medicine was very rare. Here, we present the case of a 35-year-old Chinese man, who was diagnosed with severe psoriasis and died of fatal acute arsenic poisoning after he applied a local folk prescription ointment containing mainly the realgar to the affected skin for about 4 days. The autopsy showed multiple punctate hemorrhages over the limbs, pleural effusion, edematous lungs with consolidation, mild myocardial hypertrophy and normal-looking kidneys. The histopathological examination of renal tissue showed severe degeneration, necrosis and desquamation of renal tubular epithelial cells, presence of protein cast and a widened edematous interstitium with interstitial fibrosis. The presence of arsenic in large amount in the ointment (about 6%), in blood (1.76 µg/mL), and in skin (4.71 µg/g), were confirmed analytically. We also provide the clinical records of the deceased and briefly reviewed 7 similar cases in literature (6 in Chinese and 1 in English) in the past 30 years in China.

High sulfide production induced by algae decomposition and its potential stimulation to phosphorus mobility in sediment.

This study is devoted to addressing the effects of algae blooms on sulfur cycle and the consequent phosphorus mobility in the sediments of freshwater lake ecosystems. A mesocosm experiment was conducted to investigate these effects through monitoring the dynamics of sulfur (S), iron (Fe) and phosphorus (P) in water and sediments, and their diffusion fluxes at the sediment-water interface (SWI). In addition, the abundance of sulfate-reducing bacteria (SRB) in the water column was also detected. The addition of the algae lead to an increase of SRB, a drastic decline of sulfate and a significant increase of total dissolved sulfide (ΣS2-, the peak value of near 3.0 mmol/L on day 6) in the water column. These results suggest the sulfate reduction was dramatically promoted during algae decomposition. Indeed the ΣS2- was 2 to 3 times of SO42- initial concentration, and higher ΣS2- was produced with higher algal biomass. Moreover, the diffusive flux of ΣS2- at the SWI was negative, indicating that diffusion of ΣS2- from water column toward sediment was occurring. These results indicated that algae decomposition might also be another important source of ΣS2- (termed "algae-derived ΣS2-") in addition to sulfate reduction. The increase of Fe(II) in surface sediment pore-water was slightly delayed compared to the ΣS2- generation in the water column, which illustrated that Fe oxyhydroxides in sediments were transformed into Fe(II) through chemical reduction of ΣS2-. Concomitantly, the vertical distribution of PO43- in high amounts algae group suggested that desorption and release of iron oxides-bound PO43- occurred in sediments. Collectively, algae bloom can boost the lake eutrophication not only through direct release of nutrients but also through the high production of ΣS2-and indirect promotion of phosphorus mobility in sediment.