Biological Oxygen Research Articles

Evaluation of the biodegradability of hazardous industrial solid waste: Study of key parameters.

The biological stability of solid waste is one of the main problems related to the environmental impact of landfills and their long-term emission potential. Current European legislation (European Landfill Directive, EC/99/31) introduced the need to reduce biodegradable organic compounds deposited in landfills; however, it set neither official parameters nor methods to define the stability of such a waste. In Spain, biodegradability is generally evaluated using the biological oxygen demand/chemical oxygen demand (BOD5/COD) ratio, measuring it on the leachate, thus not considering the non-soluble fraction and therefore creating false negatives. To solve this problem, the biodegradability of hazardous industrial waste has been determined by measuring its respirometric activity (AT4). Our results show that the measure of the AT4 is independent of the enrichment with a microbial inoculum, and a sample size no higher than 20g could be a reasonable value for a sensitive biodegradability determination. The highest respirometric index is obtained in waste with pH values between 6.5 and 10.5. Furthermore, respirometric biodegradability values are independent of traditional parameters of organic matter characterization such as BOD5/COD ratio, volatile content, and total and dissolved organic carbon. Consequently, the AT4 parameter provides new information on the composition and stability of organic matter in hazardous industrial waste. Its incorporation into pre-disposal waste characterization protocols allows to identify waste that exceeds recommended biodegradability thresholds. This approach ensures that only waste meeting specified biodegradability standards is deposited, avoiding landfill emissions and related environmental impacts, and thereby improving the overall effectiveness and sustainability of waste management practices.

Metrics for stabilization of fecal sludge and relation to dewatering metrics

ABSTRACT Stabilization and dewatering are essential treatment mechanisms for the management of fecal sludge (FS) that accumulates in onsite containment, but reliable predictors of treatment performance are lacking. FS in Lusaka, Zambia is typically 80–98% water, which when delivered to treatment first requires dewatering, followed by stabilization of varying levels of organic matter. In addition, varying levels of stabilization are themselves observed to influence dewatering performance. Therefore, this study evaluated rapid and low-cost metrics of stabilization and their relation to dewaterability. Fourteen metrics of stabilization were evaluated based on 11 criteria in a decision matrix. Four metrics were selected to then evaluate method performance and suitability with FS samples (n = 27). The relation between stabilization and dewatering performance of collected samples were analyzed, and also following anaerobic stabilization in the laboratory. The study found that metrics based on physical–chemical characteristics such as volatile/total solids (VS/TS) and biological oxygen demand/chemical oxygen demand (BOD/COD) were not reliable for measuring FS stabilization and its relation to dewaterability. Metrics that rely on microbial activity such as SOUR (specific oxygen uptake rate) are more promising based on the consistent results obtained throughout this study.

Lactic Acid Bacteria (LAB) from Fermented Milk Leftover for Wastewater Treatment of Soybean-Based Industries

Tempeh and tofu are widely consumed by Indonesians and easily made using simple tools and method, thus numerous home industries producing are emerging. However, soybean processing in these industries produces high volume of wastewater. This study provides a simple wastewater treatment instrument design that could be used by soybean-based home industries by applying a series of physical, chemical, and biological treatment. Physical treatment was performed by filtration, chemical by addition of alum salts, while biological treatment was done by supplementing with lactic acid bacteria (LAB) from leftover container of fermented milk. Wastewater was recorded by its parameters (temperature, pH, dissolved oxygen/DO, biological oxygen demand/BOD, turbidity) at every phase of treatment after incubation for two various of periods; 1 hour and 5 days. Results showed that wastewater treated using instrument design had changes in all of its parameters observed during the course of treatment. Wastewater treated in all phase of instrument incubated for 1 hour showed parameters approaching wastewater quality standards, thus it was safer to be disposed to environment compared to wastewater incubated for 5 days. Wastewater treatment as designed in the current study can be applied by soybean-based home industries with short incubation time to remediate wastewater produced during soybean processing before disposal.

Laser-induced singlet oxygen selectively triggers oscillatory mitochondrial permeability transition and apoptosis in melanoma cell lines

Singlet oxygen (1O2) is an electronically excited state of triplet oxygen which is less stable than molecular oxygen in the electronic ground state and produced by photochemical, thermal, chemical, or enzymatic activation of O2. Although the role of singlet oxygen in biology and medicine was intensively studied with photosensitisers, using of these compounds is limited due to toxicity and lack of selectivity. We generated singlet oxygen in the skin fibroblasts and melanoma cell lines by 1267 nm laser irradiation. It did not induce production of superoxide anion, hydrogen peroxide or activation of lipid peroxidation in these cells confirming high selectivity of 1267 nm laser to singlet oxygen. 1O2 did not change mitochondrial membrane potential (ΔΨm) in skin fibroblasts but induced fluctuation in ΔΨm and complete mitochondrial depolarisation due to opening permeability transition pore in B16 melanoma cells. 1267 nm irradiation did not change the percentage of fibroblasts with necrosis but significantly increased the number of B16 melanoma cells with apoptosis. Thus, singlet oxygen can induce apoptosis in cancer B16 melanoma cells by opening of mitochondrial permeability transition pore (PTP) but not in control fibroblasts.

Assessment of the current ecological condition of the Kakhovka reservoir

Quality assessment and analysis of a current state of natural waters, especially when it comes to reservoir waters, is a very important stage in the organization of safe drinking water supply for human life and health. The purpose of this study is to assess a current ecological state of the Kakhovka reservoir in the Dnipropetrovsk region for the period 2016–2018. The object of the study is the natural waters of the reservoir. The subject of the study is a current ecological state of the waters of the Kakhovka reservoirs within the Dnipropetrovsk region. Research methods are based on comparative-geographical, statistical, zoning and other research methods. In addition the work used: A graphic method for an integrated assessment of a surface water quality; A method for assessing the water quality in the water bodies by hydrochemical parameters. According to the results of the study of a current state of the Kakhovka reservoir waters within the Dnipropetrovsk region for the period 2016–2018, it was found that among the nine water quality indicators the priority indicators are: chemical oxygen consumption (COC) and biological complete oxygen consumption (BOcC). In most cases, these indicators were observed to exceed the limited permissible concentrations (LPC). High values of the COC indicator are a consequence of this water pollution with sewage; and high values of the BOcC index indicate a significant organic content that decomposes in the water. As a result of the analysis of the dynamics of changes in the total indicators of the LPC multiplicity, a stable improvement in the water conditions of the Kakhovka reservoir occurs in section № 4, and for other observation points an improvement in the water condition is observed in 2017 compared to 2016, and in 2018 compared to 2017 there is a deterioration in the state of natural waters.

Analysis of the pectin extraction process at recycling of secondary material resources

The object of research is the secondary material resources of processing plant and animal raw materials, namely fruit pomace and milk whey. One of the most problematic areas is that the waste of these industries has high rates of biological and chemical oxygen consumption of wastewater, which significantly impairs the operation of local and city treatment facilities. In addition, the parameters of extraction and determination of the quality indicators of the obtained product are not well defined. The processing of whey and pomace of fruit crops can reduce the environmental burden on the environment and increase the efficiency of technological processes through resource conservation and obtaining a surplus product. The problem is solved, in particular, by using the process of extracting plant waste using milk whey and the process of energy-saving membrane concentration. In the course of the study, let’s use pectin-containing plant waste from juice production, namely watermelon, pumpkin, quince, beetroot, apple and a mixture of orange and tangerine pomace. The results obtained indicate that the process of extracting apple pomace with milk whey is promising, since the highest pectin content in the extract is established for apple pomace. The main amount of pectin substances passes into the extract starting from 75 minutes to 90 minutes. Extraction-hydrolysis for 2 hours at a temperature of 85 °C, pH=2–2.5 units determines the best results. Ultrafiltration of the obtained extract makes it possible to increase the pectin content up to 3.0 % with a protein content of more than 6.0 %. The membranes used in the experiment are characterized by high selectivity for protein and pectin. The fact is established that diafiltration makes it possible to effectively purify whey-pectin concentrates from ballast impurities with simultaneous enrichment of the concentrate with high-molecular components of whey. A technological scheme for the production of pectin-whey concentrate with high organoleptic and detoxification characteristics is proposed. The proposed technological process has a number of positive features, in particular, a high content of pectin substances, high value indicators, a significant reduction in the burden on the environment, economic benefits through energy conservation and obtaining a surplus product.

Front Cover: Theoretical Investigation of Hydrogen‐Bond‐Assisted Tetradentate N4 Copper(I) Chloride and trans‐1,2‐Peroxodicopper Complexes (Eur. J. Inorg. Chem. 23/2021)

The Front Cover shows an “O2 grasshopper” captured by two “Copper scorpions” using their strong claws and tails (outer-sphere hydrogen bonds). As the key intermediate in the biological oxygenation, the trans-1,2-peroxodicopper adduct was mimicked by a variety of molecular copper complexes. The structure-activity models of hydrogen-bond-assisted tetradentate copper(I) chloride and trans-1,2-peroxodicopper complexes were established, and fundamental insights on the mimics were obtained. More information can be found in the Full Paper by G. Liang and co-workers.

Oxygen False Positives on Habitable Zone Planets Around Sun‐Like Stars

AbstractOxygen is a promising exoplanet biosignature due to the evolutionary advantage conferred by harnessing starlight for photosynthesis, and the apparent low likelihood of maintaining oxygen‐rich atmospheres without life. Hypothetical scenarios have been proposed for non‐biological oxygen accumulation on planets around late M‐dwarfs, where the extended pre‐main sequence may favor abiotic O2 accumulation. In contrast, abiotic oxygen accumulation on planets around F, G, and K‐type stars is seemingly less likely, provided they possess substantial non‐condensable gas inventories. The comparative robustness of oxygen biosignatures around larger stars has motivated plans for next‐generation telescopes capable of oxygen detection on planets around sun‐like stars. However, the general tendency of terrestrial planets to develop oxygen‐rich atmospheres across a broad range of initial conditions and evolutionary scenarios has not been explored. Here, we use a coupled thermal‐geochemical‐climate model of terrestrial planet evolution to illustrate three scenarios whereby significant abiotic oxygen can accumulate around sun‐like stars, even when significant noncondensable gas inventories are present. For Earth‐mass planets, we find abiotic oxygen can accumulate to modern levels if (1) the CO2:H2O ratio of the initial volatile inventory is high, (2) the initial water inventory exceeds ∼50 Earth oceans, or (3) the initial water inventory is very low (<0.3 Earth oceans). Fortunately, these three abiotic oxygen scenarios could be distinguished from biological oxygen with observations of other atmospheric constituents or characterizing the planetary surface. This highlights the need for broadly capable next‐generation telescopes that are equipped to constrain surface water inventories via time‐resolved photometry and search for temporal biosignatures or disequilibrium combination biosignatures to assess whether oxygen is biogenic.

The Effects of Dimethylsulfoxide and Oxygen on DNA Damage Induction and Repair Outcomes for Cells Irradiated by 62 MeV Proton and 3.31 MeV Helium Ions.

Reactive oxygen species (ROS) play an essential role in radiation-induced indirect actions. In terms of DNA damage, double strand breaks (DSBs) have the greatest effects on the repair of DNA damage, cell survival and transformation. This study evaluated the biological effects of the presence of ROS and oxygen on DSB induction and mutation frequency. The relative biological effectiveness (RBE) and oxygen enhancement ratio (OER) of 62 MeV therapeutic proton beams and 3.31 MeV helium ions were calculated using Monte Carlo damage simulation (MCDS) software. Monte Carlo excision repair (MCER) simulations were used to calculate the repair outcomes (mutation frequency). The RBE values of proton beams decreased to 0.75 in the presence of 0.4 M dimethylsulfoxide (DMSO) and then increases to 0.9 in the presence of 2 M DMSO while the RBE values of 3.31 MeV helium ions increased from 2.9 to 5.7 (0–2 M). The mutation frequency of proton beams also decreased from 0.008–0.065 to 0.004–0.034 per cell per Gy by the addition of 2 M DMSO, indicating that ROS affects both DSB induction and repair outcomes. These results show that the combined use of DMSO in normal tissues and an increased dose in tumor regions increases treatment efficiency.

Removal of Basic Violet from Wool Dyeing Effluent Using Nanoparticles

ABSTRACT In the reported study, nano silica and nano clay were used to remove the residual color from effluent generated during the dyeing of wool fabric with basic violet. Various concentrations (0.1%, 0.25%, 0.5%, and 1.0%) of the nanoparticles were treated with dye effluent for different durations and the results are compared with the color removal of commercial activated carbon. The nanoparticles were characterized for their physical properties including particle size, FTIR, and TEM. Freundlich isotherm was used for the dye adsorption studies. The FTIR and TEM analysis depicted the characteristic peaks and crystal geometry for the selected nanoparticles. The treated effluent showed a significant reduction in color, biological, and chemical oxygen demand (more than 99%). The treatment was optimized for 1.0% adsorbent concentration for 60 minutes. The color removal efficiency of nano silica was found to be higher at low concentration; however, the efficiency of nano clay exceeded at a higher concentration of adsorbents.

Diversity and Functions of Epilithic Riverine Biofilms

This article relates epilithic dry- and wet-seasonal bacterial biofilm composition to water quality along Río de la Sabana near Acapulco, Mexico. Samples were taken from various locations including nearly pristine upland locations, adjacent to residential floodplain developments, and immediately upstream from an estuarine lagoon. Bacterial composition was identified through sequential DNA analysis at the phylum, class, order, and family levels, with most of these categorized as heterotrophs, autotrophs, denitrifiers, nitrogen fixers, pathogens, and/or potential bioremediators based on generalized literature-sourced assignments. The results were interpreted in terms of location by extent of effluent pollution, and by dry versus wet seasonal changes pertaining to biofilm composition, related bacterial functions, and the following water quality parameters: temperature, pH, dissolved oxygen, biological and chemical oxygen demand, fecal and total bacteria counts, methylene blue active substances, electrical conductivity, and nitrite, nitrate, ammonium, sulfate, and phosphate concentrations. It was found that epilithic bacterial biofilm diversity was richest during the wet season, was more varied in abundance along the upland locations, and was dominated by Proteobacteria and Bacteroidetes with bioremediation and pathogen functions along effluent-receiving river locations. Low-abundance families associated with anaerobic and denitrifying functions were more prevalent during the wet season, while low-abundance families associated with aerobic, N2-fixing and pH-elevating functions were more prevalent during the dry season.

Photoactive CdO:TiO2 nanocomposites for dyes degradation under visible light

CdO:TiO2 nanocomposites were synthesized by sol-gel precipitating method for different volume ratios and examined the photoactivity of synthesized nanomaterials. The structure of nanomaterials was analysized by X-ray diffraction (XRD) while FE-SEM and HR-TEM were used for morphological property. XRD patterns showed anatase phase for TiO2 and cubic phases for CdO, respectively, where as a mixed structure was observed for CdO:TiO2. The optical bandgaps were found between 2.10 and 3.25 eV for the different volume ratios. The CdO:TiO2 (1:1) was found suitable for the degradation of both organic methyl blue and methyl orange dye under visible light. The boosted charge separation and low recombination rates were responsible to enhance the performance of the photocatalic activity in visible light. The photodegradation was increased from 75% to 99% for CdO to CdO:TiO2 for methyl orange dye at a pH value of 7. The mineralization property of the dyes was confirmed by biological oxygen and a chemical oxygen demand measurements.

Integrated electrochemical processes for textile industry wastewater treatment: system performances and sludge settling characteristics

Textile wastewater containing toxic dyes needs efficient treatment before being released into the environment. Certain dyes are known or presumed to have carcinogenic potential for humans. In this work, hybrid electrochemical processes including electrocoagulation (EC) alone and combined with electro Fenton (EF), anodic oxidation (AO) and peroxi-coagulation (PC) were tested to treat real textile wastewater using a batch reactor. A sequential EC and EF (EC-EF) process was found to be more effective. The experimental results indicated that the effectiveness of the treatment decreases in the following order: EC-EF > EC-AO > EC-PC > EC. EC-EF results showed a decrease in chemical oxygen demand (COD, 97%), total organic carbon (98%), total suspended solids (98%), and the concentration of metal species; showing that the treatment of such wastewater type can be achieved by combined EC-EF process in a one-pot bench-scale reactor. The electrical energy consumption, the iron dissolution, and the biological oxygen demand/COD ratios of EC and EC-EF processes were evaluated. Characterization of the sludge generated during EC treatment at current density of 20 mA cm− 2 was carried out. Precipitation, adsorption, and electrochemical oxidation/reduction of organic dyes and metallic ions occurred during the treatment. This investigation shows the efficiency of combined EC-EF to treat textile wastewater.

Sewage fluxes and seasonal dynamics of physicochemical characteristics of the Bhagirathi-Hooghly River from the lower stretch of River Ganges, India

ABSTRACTTo understand the temporal variations of the physicochemical characteristics of the Bhagirathi-Hooghly River (BHR), three locations representing three districts of West Bengal were selected. The material fluxes from 34 drains during pre-monsoon season was quantified. The analysis of variance (ANOVA) revealed that no significant spatial variations were observed for the physicochemical parameters, whereas seasonal variations were significant. The mean discharge was found to be highest (247.2 × 103 m3 d−1) in the midstream drains. Highest mean concentrations of dissolved oxygen (DO) (7.35 mg L−1) and nitrate (0.81 mg L −1) were observed during the post-monsoon season followed by the monsoon and pre-monsoon. According to the BIS, WHO and the European standard of water quality (pH, 6.5–8.5; Nitrate, 0–2.5 mg L−1;DO, ≥5 mg L−1), the results of the respective parameters revealed the BHR system is maintained at high to good water quality, meaning that the BHR system is slightly altered from its pristine environment. The mean concentrations of biological and chemical oxygen demands were found to be high during the monsoon season, revealing that a large quantity of refractory organic matter is transported to the eastern Bay of Bengal from the Ganges.

Biodegradability of wastewater determines microbial assembly mechanisms in full-scale wastewater treatment plants

Wastewater treatment plants (WWTPs) are critical for maintaining sustainable development in modern societies, wherein microbial populations residing in activated sludge (AS) are responsible for the removal of pollutants from wastewater. The biodegradability [biological oxygen demand/chemical oxygen demand (B/C ratio)] of influent, as a measure of the degree of available energy and toxicity to microorganisms in AS, has been hypothesized to drive AS microbial community assembly. However, the validity of this hypothesis has not been tested in full-scale WWTPs. In this study, we assessed the pollutant removal loads, the microbial community diversity, the relative importance of deterministic and stochastic assembly processes, and bio-interactions within the communities by analyzing 195 AS samples comprising nearly 5 000 000 16S rRNA sequences. Our results indicate that the effects of B/C ratio on pollutant removal loads can be perfectly reflected through biological properties, implying that B/C ratio determined WWTPs performance through affecting microbial community. Very low and/or very high B/C ratios result in low microbial diversity, strong stochastic processes, and large, complex networks, leading to low pollutant removal load of treatment. A B/C ratio of around 0.5 was optimal for system stability and efficiency. Based on the results of this study, the authors propose using the B/C ratio as an indispensable index to assess system performance and to provide an indicator of an impending process upset before function deteriorates significantly. This study provides a specific measure that can be used to evaluate strategies for process optimization and operation of WWTPs.

Using Hemoglobin as a Performance Enhancer in Rechargeable Lithium–Oxygen Batteries

We demonstrate here that hemoglobin, a biological oxygen binder/transporter, can be used as a performance-enhancing additive in nonaqueous lithium–oxygen batteries. In a fashion similar to the way hemoglobin binds and transports oxygen in the human blood, it can bind and transport oxygen in the electrolyte solution in a conventional lithium–oxygen battery. Binding and transport of oxygen into the soluble electrolyte phase enhance the efficiency of oxygen reduction reactions (ORRs) occurring at the air cathode by preventing the accumulation of solid insulating discharge products at the cathode site. We observe stable galvanostatic cycling, high specific capacity, and low polarization in the cell in the presence of hemoglobin. Electrochemical impedance spectroscopy indicates low interfacial resistance even after several rounds of galvanostatic charge–discharge cycles. We thus propose the use of oxygen-binding natural biomolecules as possible redox mediators for energy-harvesting systems utilizing oxygen electrochemistry in the future.

Bioinspired Transition-Metal Complexes as Electrocatalysts for the Oxygen Reduction Reaction.

The oxygen reduction reaction (ORR) is one of the most important reactions in life processes and energy conversion systems. To alleviate global warming and the energy crisis, the development of high-performance electrocatalysts for the ORR for application in energy conversion and storage devices such as metal-air batteries and fuel cells is highly desirable. Inspired by the biological oxygen activation/reduction process associated with heme- and multicopper-containing metalloenzymes, iron and copper-based transition-metal complexes have been extensively explored as ORR electrocatalysts. Herein, an outline into recent progress on non-precious-metal electrocatalysts for the ORR is provided; these electrocatalysts do not require pyrolysis treatment, which is regarded as desirable from the viewpoint of bioinspired molecular catalyst design, focusing on iron/cobalt macrocycles (porphyrins, phthalocyanines, and corroles) and copper complexes in which the ORR activity is tuned by ligand variation/substitution, the method of catalyst immobilization, and the underlying supporting materials. Current challenges and exciting imminent developments in bioinspired ORR electrocatalysts are summarized and proposed.

Fauna macrobentónica del río Meric (Tracia turca): composición de la comunidad en relación a la calidad del agua

Background: Benthic macroinvertebrates are commonly used as indicators of the biological condition of waterbodies. Both the benthic macroinvertebrates and the physicochemical properties of the water provide important information about the pollution of a water environment. Goals: To investigate the relationships between assemblage composition of Oligochaeta (Annelida), Chironomidae (Diptera), and other macroin­vertebrates with physical and chemical water variables in the Meric River, Turkey. Methods: This study was carried out by taking water and benthic samples at 8 stations at monthly intervals in order to determine what macrobenthic fauna exist in the Meric River and what environmental properties affect their distribution. Results: A total of 39 taxa were found and we determined that there is an average of 851 individuals per m2. Also, this study established the first records for Brachiura sowerbyii (Oligochaeta) and Pottashia alternis (Chironomidae) in the Turkish Thrace region. According to Shannon-Wiener index, while it was determined that Meric River has the highest diversity values with H’ = 0.845 at the station 4, the river has the poorest diversity with H’= 0.477 at the station 2. Also, we examined similarities of distribution of Oligochaeta taxa by station and month using the Bray-Curtis index. Accordingly, while stations 6 and 8 were determined to be the most similar to each other, stations 2 and 5 were the least similar. The relationships between Oligochaeta taxa and physical and chemical parameters of water were evaluated using the Spearman Correlation index. As a result, we found that water temperature, pH, electrical conductivity, hydrogen sulfide, calcium, magnesium, phosphate, chlorine, salinity, dissolved oxygen and biological oxygen have positive correlations with some species of Oligochaeta, while nitrate and nitrite have negative correlations with some species of Oligochaeta. Conclusions: We made a number of suggestions for sustainable usage of this river.

Degradation of tetracycline by solar photo‐Fenton: Optimization and application in pilot photoreactor

AbstractThe objective of this study is to analyze the photodegradation of the antibiotic tetracycline by the solar photo‐Fenton process. The optimal conditions were obtained in a 2² (2 × 2) factorial design with the following input variables: reaction time and catalyst concentration (ferrous ion [Fe2+]). After statistical analysis using the Statistica 7.0 software, the optimal conditions determined, time = 120 min and Fe2+ = 166.81 mg/L, were applied in a pilot scale photoreactor, resulting in an 88.7% removal of the drug. In addition, in this stage we studied the reaction kinetics, biodegradability, and phytotoxicity of the products generated by the process. In the kinetic study, a constant of 1.82 × 10−2 min−1 was obtained. For this constant, a reaction time of 38.16 min is required for the initial tetracycline concentration to be reduced by 50%. The biodegradability tests indicated a gradual increase in the five‐day biological oxygen demand/chemical oxygen demand ratio over time. The phytotoxicity tests showed an 18.5% decrease in the inhibition rate of the root growth of lettuce seedlings, indicating that the treatment applied reduces the toxicity of the substance.

On diel variability of marine sediment backscattering properties caused by microphytobenthos photosynthesis: Impact of environmental factors

Abstract The study has been motivated by the development of the hydroacoustic techniques for mapping and classifying the benthic habitats and for the research of the microbenthos photosynthesis in the semi-enclosed Baltic Sea, particularly sensitive to human activity. The investigation of the effect of the benthic microalgal photosynthesis on the echo signal from the Baltic sandy sediments is continuing. The study clarifies the impact of the abiotic and biotic factors on the diel variation of the backscattering caused by the benthic microalgal photosynthetic activity. Five multiday laboratory experiments, different in hydrophysical or biological conditions, were conducted. During each measurement series, the “day” (illumination) and “night” (darkness) conditions (L:D cycle) were simulated and the diel variations of the echo energy of the backscattered signal were analyzed. The hydroacoustic data were acquired along with measuring biological and biooptical parameters and oxygen concentration. The study demonstrated the impact of microphytobenthos photosynthesis on the backscattering properties of the marine sediment which is sensitive to the illumination level, benthic microalgal biomass and macrozoobenthos bioturbation.