Oxygen Nanobubble Research Articles

Effects of hyperoxia during oxygen nanobubble treatment on innate immunity, growth performance, gill histology, and gut microbiome in Nile tilapia, Oreochromis niloticus

Oxygen nanobubble (NB–O2) technology has been introduced to the aquaculture industry in recent years. This treatment usually results in a tremendously high level of dissolved oxygen (DO) in the water. However, little is known about the possible negative effects of hyperoxia due to NB-O2 treatment (hyper-NB-O2) on farmed fish. Here, we investigated i) the effect of short-term hyper-NB-O2 exposure (single treatment) on the innate immunity in Nile tilapia, Oreochromis niloticus, and ii) the effect of long-term hyper-NB-O2 exposure (26-day treatments) on survival, growth performance, gill histology, and gut microbiome in Nile tilapia. A single treatment with NB-O2 for 10 min in 50 L of water resulted in 24.2 ± 0.04 mg/L DO (approximately 2-3 × 107 nanoscale oxygen bubbles/mL). This treatment did not result in differences in expression of several immune-related genes (e.g., TNF-α, LYZ and HPS70) in various tissues (e.g., gill, head kidney, and spleen) compared to the non-treated control. Over a 26-day period of exposure, no significant differences were observed in survival and growth performance of the fish, but minor histological changes were occasionally noted on the gills. Analysis of the gut microbiome revealed a significant increase in the genera Bosea, Exiguobacterium, Hyphomicrobium, and Singulisphaera in the group receiving NB-O2. Moreover, no signs of “gas bubble disease” were observed in the fish throughout the duration of the experiment. Overall, these results suggest that both short- and long-term hyper-NB-O2 exposure appears to be benign and has no obvious adverse effects on fish.

Evaluation of nanobubble technology for the reduction of suspended solids and turbidity in Lake Amatitlán, Guatemala

Lake Amatitlán in Guatemala is in accelerated process of contamination and artificial eutrophication, having a high amount of suspended solids, these cause the appearance of the water to be turbulent. The purpose of the research was to evaluate the ability of oxygen nanobubble technology to minimize all particulate matter and reduce turbulence. The investigation consisted of taking a sample of 33 m³ of water with a high organic load and cyanobacteria, Microcystis aeruginosa. Oxygen nanobubble was applied for eight days operating two hours and 45 minutes per day, making a total of 19 hours. Six samples were obtained, the first was the control sample. The results obtained were favorable with a recorded reduction of suspended solids from 73.39% to 64.05%. The final results were compared with quality standards of oligotrophic algos from Mexico and Peru.

A Double-Blind, Randomized, Placebo-Controlled Pilot Study examining an Oxygen Nanobubble Beverage for 16.1-km Time Trial and Repeated Sprint Cycling Performance

There is growing interest of ergogenic aids that deliver supplemental oxygen during exercise and recovery, however, breathing supplemental oxygen via specialist facemasks is often not feasible. Therefore, this study investigated the effect of an oxygen-nanobubble beverage during submaximal and repeated sprint cycling. In a double-blind, randomized, placebo-controlled study, 10 male cyclists (peak aerobic capacity, 56.9 ± 6.1 mL·kg−1·min−1; maximal aerobic power, 385 ± 25 W) completed submaximal or maximal exercise after consuming an oxygen-nanobubble (O2) or placebo (PLA) beverage. Submaximal trials comprised 30-min of steady-state cycling at 60% peak aerobic capacity and 16.1-km time-trial (TT). Maximal trials involved 4 × 30 s Wingate tests interspersed by 4-min recovery. Time-to-completion during the 16.1-km TT was 2.4% faster after O2 compared with PLA (95% CI = 0.7–4.0%, p = 0.010, d = 0.41). Average power for the 16.1-km TT was 4.1% higher for O2 vs. PLA (95% CI = 2.1–7.3%, p = 0.006, d = 0.28). Average peak power during the repeated Wingate tests increased by 7.1% for O2 compared with PLA (p = 0.002, d = 0.58). An oxygen-nanobubble beverage improves performance during submaximal and repeated sprint cycling, therefore may provide a practical and effective ergogenic aid for competitive cyclists.

Confined Electrochemical Behaviors of Single Platinum Nanoparticles Revealing Ultrahigh Density of Gas Molecules inside a Nanobubble.

Understanding the basic physicochemical properties of gas molecules confined within nanobubbles is of fundamental importance for chemical and biological processes. Here, we successfully monitored the nanobubble-confined electrochemical behaviors of single platinum nanoparticles (PtNPs) at a carbon fiber ultramicroelectrode in HClO4 and H2O2 solution. Due to the catalytic decomposition of H2O2, a single oxygen nanobubble was formed on individual PtNPs to block the active surface of particles for proton reduction and to suppress their stochastic motion, resulting in significantly distinguished current traces. Furthermore, the combination of theoretical calculations and high-resolution electrochemical measurements allowed the nanobubble size and the oxygen gas density inside a single nanobubble to be quantified. Moreover, the ultrahigh oxygen density inside (1046 kg/m3) was revealed, indicating that gas molecules in a nanosized space existed with a high state of aggregation. Our approach sheds light on the gas aggregation behaviors of nanoscale bubbles using single-entity electrochemical measurements.

Nanobubbles: Fundamentals and recent drug delivery applications

The emerging branch in pharmaceutical sciences known as pharmaceutical nanotechnology presents new tools, opportunities and scope, which are expected to have significant applications, in disease diagnostics and therapeutics. There is a growing interest in nanobubble (NB) technology because of its wide range of potential applications in theranostics and targeted drug delivery including anticancer drug delivery, antibiotic delivery, gene delivery etc. Nanobubbles could offer several features in anticancer drug delivery, improving cellular uptake of chemotherapy drugs into cancer cell lines. Nanobubbles opened a new field of ultrasound imaging and were used as a diagnostic method. Generally, the delivery of drugs to organs and tissues is affected by two main ultrasound effects including the cavitation and sonoporation effects. This review describes the history of nanobubble, nomenclature, stability of nanobubble, physicochemical properties, characterization of nanobubble, method of preparation and applications. This article aims at highlighting the most recent and promising research trends including oxygen nanobubble, silica nanobubble and pluronicnanobubble and enlist the various drug delivery approaches involving the application of nanobubbles.

Effect of nanobubbles (oxygen, ozone) on the Pacific white shrimp (Penaeus vannamei), Vibrio parahaemolyticus and water quality under lab conditions

This study assessed the effects of oxygen and ozone nanobubbles on gill morphology, weight gain, and mortality of Pacific white shrimp (Penaeus vannamei), as well as the level of Vibrio parahaemolyticus and water quality of shrimp culture tanks under lab conditions. Two experiments were carried out with oxygen macrobubble, ozone macrobubble, oxygen nanobubble, ozone nanobubble, and control treatments (air-stone macrobubble). Experiments were done in triplicate in 100 L tanks with 15‰ saline water, and 20 shrimp per tank. Tanks in Experiment 1 were not inoculated with bacteria; tanks in Experiment 2 were inoculated with V. parahaemolyticus at a concentration of 106 CFU/mL. The results revealed that short treatments with ozone nanobubbles had minimal impact on shrimp gills, mortality, and growth rates, reduced V. parahaemolyticus concentration in water compared to the other groups, and improve water quality. These laboratory results indicate that ozone nanobubble treatment may be useful for controlling V. parahaemolyticus. More work is needed to find the best protocol to apply the technology on a commercial scale.

Molecular dynamics simulation of bulk nanobubbles

The long-term stability of nanobubbles with high internal gas pressure is a puzzling question for nanobubble researchers. The classical Molecular Dynamics simulation based on LAMMPS software was used to evaluate the performance of an oxygen nanobubble with high gas density. This research consists of two main cases. In the first case, bubble behavior was examined with 3247 O2 molecules embedded in a 4.5 nm radius spherical volume to represent the bubble and was surrounded by 438,490 H2O molecules with 1 g/cm3 density. In the second case, the parametric study was conducted while maintaining the same parameters where the amount of O2 molecules changed at the initial configuration. Hence six different O2 bubble configurations were simulated under two different temperature settings, 20 ℃ and 30 ℃. The Lennard Jones potentials are used for molecular interactions. The simulations were run first under the NVT and then changed to the NPT ensemble. Simulation results were analyzed for bubble size, pressure, surface tension, gas diffusion, the influence of internal initial gas densities, gas concentration, and temperature conditions. The high initial gas concentration with high initial internal gas density causes a more stable bubble condition under both NVT and NPT ensembles. This stability can be attributed to the gas supersaturation conditions. The systems with low initial internal gas densities transferred to a smaller radius gas cluster with a high internal density as they shifted to the NPT ensemble. The system with a higher temperature causes elevated system pressures at NVT and volume expansion during NPT. Under NVT simulation, bubble size was higher at lower temperatures. Under NPT conditions, bubble size increases for larger initial density cases and decreases for lower density cases. Further increased temperature causes faster gas diffusion, and higher internal bubble pressure leads to unstable conditions.

Solid-liquid-gas reaction accelerated by gas molecule tunnelling-like effect.

Solid-liquid-gas reactions are ubiquitous and are encountered in both nature and industrial processes1-4. A comprehensive description of gas transport in liquid and following reactions at the solid-liquid-gas interface, which is substantial in regard to achieving enhanced triple-phase reactions, remains unavailable. Here, we report a real-time observation of the accelerated etching of gold nanorods with oxygen nanobubbles in aqueous hydrobromic acid using liquid-cell transmission electron microscopy. Our observations reveal that when an oxygen nanobubble is close to a nanorod below the critical distance (~1 nm), the local etching rate is significantly enhanced by over one order of magnitude. Molecular dynamics simulation results show that the strong attractive van der Waals interaction between the gold nanorod and oxygen molecules facilitates the transport of oxygen through the thin liquid layer to the gold surface and thus plays a crucial role in increasing the etching rate. This result sheds light on the rational design of solid-liquid-gas reactions for enhanced activities.

Investigating water quality and disease in white leg shrimp (Penaeus vannamei) culture applying Nanobubble technology

This study evaluates the variation of water quality, microbiology, gill morphology and shrimp growth of the intensive white leg shrimp (Penaeus vannamei) applying Nanobubble technology. The experiment consisted of 9 commercial concrete tanks with a volume of 25-35 m3divided into 3 treatments of oxygen Nanobubble (O2-NB), ozone Nanobubble (O3-NB), and control (CTRL), 3 tanks for each treatment. O2-NB and O3-NB were provided to the tanks for 1 hour/day during the culture period from stocking to harvest. Shrimps were stocked at a density of 300 shrimp/m3 and applied with the same care and environmental management protocol such as feeding, water change, aeration, siphon, and microbiological treatment. The results showed that the pH, DO, and ORP parameters are affected by the O2-NB and O3-NB treatments. The average concentration of total Vibrioin the water of the O2-NB group was 1.41 times higher than that of the control group, and 1.51 times higher than that of the O3-NB group. The gill tissue of the shrimp was affected and changed to different degrees but did not reduce the survival rate of the shrimp in the experimental treatments. The harvest weight of shrimp of the control, O2-NB, and O3-NB treatments were 11.50±2.29, 11.48±2.66, and 13.87±1.65 g/shrimp, respectively. Research results exhibited that O3-NB treatment increased DO, reduced total Vibrio in water and increased growth rate compare to the control and O2-NB treatments. Reducing Nanobubble generator running time should be considered to minimise the impact on shrimp gills.

L-Proline adsorbed oxygen-loaded nanobubbles in-situ gel for wound healing

AimWound healing is a natural physiological process that restores the damaged layers of the skin by the migration and proliferation of fibroblasts. This present research work aimed to develop a nanoformulation gel of oxygen and L-proline to offer a synergistic effect on the wound healing process for better patient compliance and protection from cross-infections. Main methodsThe nanobubbles were prepared using the gas entrapment method, followed by cold addition for the synthesis of in-situ gel and further characterized by different parameters like dissolved oxygen level, particle size and zeta potential, in-vitro, ex-vivo release and animal studies. Key findingsL-Proline oxygen nanobubbles in-situ gel formulation was prepared by incorporating oxygen concentration of 15.5 mg/L at pH 5.6. The concentration of dissolved oxygen was stabilized for 6 h and displayed synergistic effects with L-proline at the sol-gel transition temperature. In-vivo studies demonstrated complete wound healing in 21 days and 27 days for oxygen nanobubble with L-proline and control group, respectively. SignificanceThis controlled release nanoformulation showed a combinational effect of oxygen and L-proline for reducing the frequency of application compared to the marketed formulation.

Oxygen and Ozone Nanobubble Increase the Postharvest Quality of Cut Cymbidium ‘Lovely King’

Oxygen and Ozone Nanobubble Increase the Postharvest Quality of Cut Cymbidium ‘Lovely King’

Fundamental Investigation on a Foam-Generating Microorganism and Its Potential for Mobility Reduction in High-Permeability Flow Channels

This study proposed a novel foam EOR technique using Pseudomonas aeruginosa to generate the foam and investigated the potential of the microbial foam EOR to modify the permeability of a high-permeability porous system. We investigated oxygen nanobubble, carbon dioxide nanobubble and ferrous sulfate concentrations to discover the optimal levels for activating the foam generation of the microorganism through cultivation experiments. We also clarified the behavior of the microbial foam generation and the bioproducts that contribute to the foam generation. The potential of the foam to decrease the permeability of high-permeability porous systems was evaluated through flooding experiments using sand pack cores. The foam generation became more active with the increase in the number of nanobubbles, while there was an optimal concentration of ferrous sulfate for foam generation. The foam was identified as being induced by the proteins produced by the microorganism, which can be expected to bring about several advantages over surfactant-induced foam. The foam successfully decreased the permeability of high-permeability sand pack cores to half of their initial levels. These results demonstrate that the microbial foam EOR has the potential to decrease the permeability of high-permeability porous systems and improve the permeability heterogeneity in oil reservoirs.

Sustainable restoration of anoxic freshwater using environmentally-compatible oxygen-carrying biochar: Performance and mechanisms

The long-term decline in dissolved oxygen (DO) levels in freshwater systems including rivers and lakes has become a worldwide concern, which can threaten biodiversity, nutrient biogeochemistry, water quality and ultimately human health. Herein, we report a sustainable restoration strategy for anoxic freshwater using local sediment-based biochar as novel oxygen nanobubble carriers. Column incubation experiments were conducted with water and sediment samples from an urban tributary of the Yangtze River. The oxygen-carrying sediment-based biochar (O-SBC) showed long-lasting re-oxygenation performance for anoxic river waters during 28-day period, in which DO was rapidly elevated from ∼0.14 to ∼7.87 mg/L and gradually maintained at ∼4.78 mg/L until the end. O-SBC with multiple functions switched the sediments from a source to a sink of nutrients, and its release of oxygen nanobubbles contributed further decrements of 66.3% NH4+-N and 142.9% PO43−-P except for physical blocking and physicochemical adsorption. Notably, a comprehensive focus on restoration mechanism was explored in view of microbial community response. The re-oxygenation was followed by a ∼5.05% increase of bacterial diversity (Shannon index) in water, but a ∼2.40% decrease in sediments. A proliferation of some specific aerobic populations was observed, of which the nitrifying Nitrospira abundances were ∼10-fold higher in the water from O-SBC than the control. Additionally, functional genes involved in nitrous oxide reduction, polyphosphate synthesis/degradation, and thiosulfate oxidation were also enriched. Taken together, our findings can not only expand the promising candidates for oxygen nanobubble carriers based on sediment recycling, but also highlight the microbial molecular mechanisms for anoxic freshwater restoration based on nutrient cycle regulation.

Germination and Seedling Growth Response of Sprouts and Leafy Vegetables after Applying Oxygen Nanobubble Water

Background and objective The nanobubbles remain stable in water, and it increased dissolved oxygen (DO) in the water that promotes the seed germination and the plant growth. We evaluated the seed germination and growth of sprouts (radish, wheat, and barley) and leafy vegetables (red mustard and pak choi) when irrigated with various DO of nanobubble water (NB). Methods The oxygen NB was generated by surface friction and treated in 4 levels: NB 0% (control, DO 9.21 mg·L−1), NB 20% (DO 15.40 mg·L−1), NB 33% (DO 20.93 mg·L−1), and NB 100% (DO 39.29 mg·L−1). Results The root length of radish and wheat increased more in NB 33% than the control plot. The fresh weight increased in NB 33% compared to the control plot in radish and wheat, and both fresh and dry weight increased more in NB 20%, NB 33%, and NB 100% than the control plot of barley. The leaf length and width of red mustard decreased more in NB 33% and NB 100% than the control plot and NB 20%, which indicated the leaf compactness. The fresh and dry weight of shoot and root increased more in NB 100% than the control plot in red mustard. In pak choi, the shoot fresh weight increased more in NB 100% than the control plot. In leafy vegetables, the germination rate of red mustard in NB 100% was higher than the control plot, however, it was not significantly different between oxygen NB plots in sprout vegetables. Conclusion The results showed that the root growth and biomass increased after applying NB 33% in sprout vegetables. The leaf growth properties as the number of leaves and leaf size were not significantly different or decreased in NB treatments compared to control plots, but NB 100% (DO 39.29 mg·L−1) effectively increased the root growth and plant biomass in leafy vegetables.

Reducing arsenic toxicity using the interfacial oxygen nanobubble technology for sediment remediation

The arsenic (As)-bearing eutrophic waters may suffer from the dual conditions of harmful algal blooms and release of As, driven by algal-induced hypoxia/anoxia. Here, we investigate the use of interfacial oxygen (O2) nanobubble technology to combat the hypoxia and control As exposure in simulated mesocosm experiments. It was observed that remediation of algal-induced hypoxia at the sediment-water interfaces (SWI) by application of O2 nanobubbles reduced the level of dissolved As from 23.2 μg L−1 to <10 μg L−1 and stimulated the conversion of As(III) to the less toxic As(V) (65–75%) and methylated As (10–15%) species. More than half of the oxidation and all the methylation of As(III) resulted from the manipulation by O2 nanobubbles of microbes responsible for As(III) oxidation and methylation. Hydroxyl radicals were generated during the oxidation of reductive substances at the SWI in darkness, and should be dominant contributors to As(III) abiotic oxidation. X-ray absorption near-edge structure (XANES) spectroscopic analysis demonstrated that surface sediments changed from being sources to acting as sinks of As, due to the formation of Fe-(hydr)oxide. Overall, this study suggests that interfacial O2 nanobubble technology could be a potential method for remediation of sediment As pollution through the manipulation of O2-related microbial and geochemical reactions.

Control ofVibrioparahaemolyticus(AHPND strain) and improvement of water quality using nanobubble technology

Nanobubble technology is used in wastewater treatment, but its disinfectant properties in aquaculture have not been clearly demonstrated. This study investigated the ability of nanobubbles to reduce Vibrio parahaemolyticus (AHPND strain) and to improve water quality. Two laboratory experiments were conducted over a one-week period, that is (a) assessing the effects of air and oxygen nanobubbles for 60 minutes per day and (b) comparing effects of ozone nanobubble treatments for 2, 4 and 6 minutes per day. Experiments were done in triplicate 100 L tanks with 15‰ saline water, inoculated with an initial bacterial concentration of 106 CFU/ml. At the end of experiment 1, the bacterial concentration of the air and oxygen nanobubble groups was counted for 69% and 46% of the control group respectively. At the end of experiment 2, the bacterial concentration of the 2-, 4- and 6-minute ozone nanobubble groups were counted for 23%, 2.2% and 0% of the control group respectively. Oxygen and ozone nanobubbles significantly increased oxygen reduction potential and oxygen values. Results indicate that under effective dosages nanobubbles can be used in the production farms to control V.parahaemolyticus and increase oxygen levels.

Molecular dynamics analysis of shock wave-induced nanobubble collapse in water

The nanobubbles contained in the human body are induced to collapse by the shock wave, and thus produce a strong impact and high-speed nanojet, resulting in trauma to human tissues. The collapse of nanobubbles in water caused by shock waves is investigated by molecular dynamics. Nanobubbles are divided into three types: vacuum nanobubble, carbon dioxide nanobubble, and oxygen nanobubble. The influence of factors such as the number of gas molecules, the diameter of the nanobubbles, and the impulse of the shock wave on the bubble collapse are considered separately. The results show that the addition of gas molecules to vacuum nanobubbles does not affect the propagation of shock waves. However, before the nanobubbles are completely collapsed, the maximum velocity of the nanojet formed by the collapse of nanobubbles containing 718 carbon dioxide molecules (or 733 oxygen molecules) is larger than that of vacuum and nanobubbles containing 1368 carbon dioxide molecules (or 1409 oxygen molecules). After the nanobubbles are completely collapsed, the gas molecules cause the velocity of the nanojet to decay, and finally the maximum velocity of the nanojet containing gas molecules is less than that of the vacuum nanojet. In addition, it is also found that the collapse time of nanobubbles is short at high impulse, and the density and pressure when the shock wave passes at the same time are both greater. After the bubble collapses, the maximum velocity of the nanojet is larger, and the impact force is much stronger than that at a small impulse. Larger diameter nanobubble has a longer collapse time, and the density and pressure when the shock wave passes at the same time are both smaller, and the shock wave propagation is slower, but the maximum speed of the nanojet is larger. The impact is stronger. The greater the maximum velocity of the nanojet, the greater the distance that is dispersed by the gas molecules of the gas-containing nanobubbles in the impact direction will be and the deeper the depression.

Investigation of the possibility of culturing aerobic yeast with oxygen nanobubble addition and evaluation of the results of batch and semi-batch cultures of Saccharomyces cerevisiae

Nanobubble dispersions have been intensively studied in recent years. Their expanding applications include a wide range of industrial and biochemical processes. Nanobubble-saturated water intensifies the growth of bacteria, animal cell lines, plants, and animals. However, their influence on yeast growth has not been investigated. Yeast is an important microorganism in the biotechnology and food industries. Intensified growth of yeasts would be beneficial for basic and industrial purposes. In this study, the possibility of culturing Saccharomyces cerevisiae with oxygen nanobubbles as the sole source of oxygen was investigated. Batch, sequential batch, and semi-batch cultures were grown with the addition of oxygen nanobubbles, along with classical aeration of the bioreactor. The results were compared to batch cultures without nanobubble addition. Biomass, substrate, and oxygen profiles were determined throughout the time of culture. The Monod and Tsao–Hanson models were used to describe yeast growth. The balance of the bioreactor culture was determined using MATLAB software. The comparison of balance and kinetic parameters demonstrated a higher maximum specific growth rate of yeast in nanobubble cultures than in cultures without nanobubble addition.

Oxygen nanobubbles enhanced photodegradation of oxytetracycline under visible light: Synergistic effect and mechanism

Nanobubbles have gained much attention due to their unusual properties such as large specific surface area, surface energy and internal energy, thereby, increase the surface reaction and improve the mass transfer efficiency. The long term stability of nanobubbles and generation of reactive oxygen species enables them to address various environmental issues for water purification without secondary pollution. However, there are few studies concerning the application of oxygen nanobubbles in the advanced oxidation processes (AOPs). In this study, first time, oxygen nanobubbles were introduced into the photoreaction system under visible light irradiation for enhanced photodegradation of oxytetracycline (OTC). Results indicated that oxygen nanobubbles significantly improved the photodegradation of OTC through high mass transfer and generation of reactive radicals during the nanobubble collapse. The oxygen nanobubble stability was confirmed to be pH dependent. The nanobubbles concentration increased from 0.76 to 3.78 × 108 particles/mL, while the mean size decreased from 205 nm to 138 nm as the pH value increased (3.2–11.0). The photodegradation efficiency of OTC was improved from 45% to 98% with the increase of pH (4.0–11.0). Oxygen nanobubbles hold promise to improve the AOPs, such as reducing catalysts and chemicals usage and costs. Quenching experiments demonstrated that OH was the predominant active species induced the photodegradation of OTC. With the development of nanobubbles technology, it is anticipated to realize totally chemicals free green technology. This study provides a novel nanobubble/AOPs technology, which will be more efficient and environmental friendly and will have broad application in waste water treatment and drinking water purification.

Anoxia remediation and internal loading modulation in eutrophic lakes using geoengineering method based on oxygen nanobubbles

Benthic anoxia and internal P release, widely occurring in eutrophic lakes, are major factors threatening the health of aquatic ecosystems. In this paper, we experimentally evaluated the efficacy of a new type of “flock-lock” geoengineering method based on oxygen nanobubble technology to remediate sediment anoxia and reduce the internal P release in waters with and without algal blooms. Oxygen-carrying materials (OCM) modified from natural zeolites were used as capping agents and an oxygen-locking layer consists of OCM and the oxidized sediment was formed between anoxic sediment and overlying water. The synergy of diffusion and retention of oxygen in this layer contributes to both the increase of DO and reversal of anoxic conditions. By capping with OCM, the DO in overlying water improved instantly from around 1.5 mg/L to 3.5–4 mg/L and 5–6 mg/L in the systems with algal blooms and without algal blooms, respectively, and maintained throughout the incubation period. The oxygen penetration depth in the sediment can be significantly enhanced from around 0 cm to 3 cm and form an oxygen-locking layer at the end of the experiment by capping with OCM. The labile P was effectively retained via the re-oxidation of ferrous iron in this layer compared with the obvious release of labile P and Fe in control. More importantly, the oxygen depletion and labile P increase at the sediment-water interface caused by the decomposition of the deposited algal biomass can be substantially eliminated after capping with OCM. The study shed insights on the sustainable modulation of sediment anoxia and internal loading in eutrophic waters.