Distribution Of Dissolved Oxygen Research Articles

Recent changes of the dissolved oxygen distribution in the deep convection cell of the southern Adriatic Sea

The dynamics of dissolved oxygen in the ocean are of crucial importance for understanding marine ecosystems, with influences ranging from exchange with the atmosphere to biological processes and ocean circulation. In this study, we focus on the southern Adriatic Sea, an essential component of the Eastern Mediterranean “conveyor belt”, to investigate long-term oxygen dynamics and its driving factors. We use cross-platform datasets from 2013 to 2020, including remote sensing data, model reanalysis and in-situ observations from Argo floats, ocean gliders and ship-based measurements. Our analysis investigate the interplay of physical, biological and atmospheric forcing that drive oxygen variability. The distribution of dissolved oxygen in the southern Adriatic Sea is influenced by vertical mixing, advection of water masses and ecosystem dynamics. In the surface layer, the variability of dissolved oxygen is triggered by annual primary production and deep convection events. The dynamics in the intermediate and the deep layers are instead primarily influenced by physical processes, such as the vertical mixing and the water masses inflow from the adjacent sub-basins, which is driven by the periodic reversals of northern Ionian Gyre circulation. In particular our study reveals that the water masses advective dynamics driving the increase and decrease of dissolved oxygen have drastically changed in recent years. The highest dissolved oxygen concentrations are currently observed during the northern Ionian Gyre anticyclonic phase, while they have been previously documented during the cyclonic phase. This change appears to be connected with the significant increase in salinity observed in the southern Adriatic Sea in the same period and contributes to a better understanding of the processes that determine oxygen distribution in the Eastern Mediterranean basin.

A diatom extension to the cGEnIE Earth system model – EcoGEnIE 1.1

Abstract. We extend the ecological component (ECOGEM) of the carbon-centric Grid-Enabled Integrated Earth system model (cGEnIE) to include a diatom functional group. ECOGEM represents plankton community dynamics via a spectrum of ecophysiological traits originally based on size and plankton food web (phyto- and zooplankton; EcoGEnIE 1.0), which we developed here to account for a diatom functional group (EcoGEnIE 1.1). We tuned EcoGEnIE 1.1, exploring a range of ecophysiological parameter values specific to phytoplankton, including diatom growth and survival (18 parameters over 550 runs) to achieve best fits to observations of diatom biogeography and size class distribution as well as to global ocean nutrient and dissolved oxygen distributions. This, in conjunction with a previously developed representation of opal dissolution and an updated representation of the ocean iron cycle in the water column, resulted in an improved distribution of dissolved oxygen in the water column relative to the previous EcoGEnIE 1.0, with global export production (7.4 Gt C yr−1) now closer to previous estimates. Simulated diatom biogeography is characterised by larger size classes dominating at high latitudes, notably in the Southern Ocean, and smaller size classes dominating at lower latitudes. Overall, diatom biological productivity accounts for ∼20 % of global carbon biomass in the model, with diatoms outcompeting other phytoplankton functional groups when dissolved silica is available due to their faster maximum photosynthetic rates and reduced palatability to grazers. Adding a diatom functional group provides the cGEnIE Earth system model with an extended capability to explore ecological dynamics and their influence on ocean biogeochemistry.

KAJIAN KUALITAS AIR DI PERAIRAN DESA SUMBERKIMA DAN DESA PEMUTERAN, KECAMATAN GEROKGAK, KABUPATEN BULELENG, PROVINSI BALI

Water quality has a significant impact on aquaculture productivity. Water quality characteristics influence fishing production. This study employs numerous prior research techniques to assess air quality factors such as Total Suspend Solid (TSS), salinity, Sea Surface Temperature (SST), and dissolved oxygen. However, physical elements such as rainfall, which are separated into wet and dry months in this study, have an impact on water quality. The approach was developed using Landsat-8 OLI satellite images. The algorithm's output is validated for data accuracy using Pearson correlation, root mean square error (RMSE), and R-square. The findings suggest that the distribution of water quality in dry and rainy months is low in coastal areas and high in locations adjacent to open waters. Furthermore, it was discovered that the average value of the distribution of TSS in dry months was lower than in wet months, the mean value of the distribution of salinity in dry months was higher than in wet months, the average value of the SST distribution in dry months was higher than in wet months, and the mean value of the dissolved oxygen distribution in dry months was lower than in wet months.
 Keywords: Water suitability; Landsat-8; Water Quality; Remote Sensing

Non-uniform dissolved oxygen distribution and high sludge concentration enhance simultaneous nitrification and denitrification in a novel air-lifting reactor for municipal wastewater treatment: A pilot-scale study

Achieving simultaneous carbon and nitrogen removal with sludge-liquid separation in a single reactor offers a solution to land shortages and improves treatment efficiency in municipal wastewater treatment plants of megacities. This study proposes a novel air-lifting continuous-flow reactor configuration with an alternative-aeration strategy that creates multi-functional zones for anoxic, oxic, and settlement processes. The optimal operating conditions for the reactor include a long anoxic hydraulic retention time, low dissolved oxygen (DO) in the oxic zone, and no specific reflux for external nitrifying liquid, which exhibit a high nitrogen removal efficiency of over 90% in treating real sewage with C/N < 4 in the pilot-scale study. Results show that a high sludge concentration and a low DO concentration facilitate simultaneous nitrification and denitrification, and a well mixing of sludge and substrate in different reaction zones promotes mass transfer and microbial activity. The long-term operation enriches functional microbes for carbon storage and nutrient removal.

Tracking of Dissolved Oxygen Distribution and Consumption Pattern in a Bespoke Bacterial Growth System

Microbial cells are used to produce valuable bioproducts. Dense cultures, however, have a high demand for dissolved oxygen which is challenging, considering the low solubility of oxygen in liquid. This study of design and simulation of a gaslift bioreactor highlights a vital limitation of growth, which is the oxygen limitation and sustain aerobic cultures. The aerobic growth has the effect of greatest resource efficiency in that the highest fraction of dosing is done with the largest concentration driving force near critical dissolved oxygen levels and the lowest fraction occurs with near saturated dissolved oxygen values. The results indicate that oxygen homogeneously distributed with limited dead zones at the bottom. The developed system produces 40.5 % more biomass compared with conventional systems, which suffer from oxygen depletion.

Depth Profiles of Dissolved Oxygen (DO) and Hydrogen Sulfide (H2S) Concentration in a Tropical Freshwater Reservoir

This study aims to determine the profile of dissolved oxygen and H2S based on depth in the Jatiluhur Reservoir related to fish culture in floating net cages. The scope of this research is focused on the location of floating net cage cultivation. Dissolved oxygen distribution is classified as a positive heterograde type where dissolved oxygen levels higher in the metalimnion layer due to the photosynthesis process that occurs effectively by aquatic plants and phytoplankton. Jatiluhur Reservoir shows signs of organic pollution, with BOD5 and COD levels exceeding the quality standard. This organic substance comes from the waste of floating net cages. BOD5 and COD values that exceed the quality standard result in increased oxygen consumption during the decomposition process; therefore, a hypoxic layer occurs. This occurrence can cause water conditions to become anoxic, producing H2S gas. The H2S value in the Jatiluhur Reservoir was observed to exceed 0.002 mg/L and showed an increase in the metalimnion layer.

Пространственно-временна́я изменчивость гидрохимических показателей водной среды Обской и Тазовской губ

The Gulf of Ob and Taz Bay are components of a special geographical object — Ob-Tar estuarine area. They are intensively used by companies, which produce natural gas and oil in the Yamal Region. The aim of the study is to assess the spatial patterns and temporal dynamics of the priority hydrochemical characteristics of the Gulf of Ob and Taz Bay. The data of the Arctic estuarine expeditions (1968—1989) and complex expeditions (2012—2013), organized by the Arctic and Antarctic Research Institute, are used as the research materials The authors have analyzed hydrochemical characteristics: pH, salinity, dissolved oxygen, silicon and phosphorus compounds. In summer-autumn period 2012—2013 there was a significant seawater intrusion to the south of the Gulf of Ob, caused by a small runoff of rivers the in these dry years. Dissolved oxygen distribution is determined by seasonal variability. In summer-autumn period the average values of more than 7 mg/l were observed. In winter, in the southern part of Gulf of Ob and Taz Bay there was an extreme oxygen deficit, dissolved oxygen values dropped below 1 mg/l. A tendency for a decrease in the content of silicon and phosphorus compounds from south to north was noted. Concentrations of phosphorus-containing compounds in the whole water area were low. The condition of Taz Bay and southern part of the Gulf of Ob is mainly determined by the river runoff and the hydrochemical regime in the area. In the period of high waters the regime has features inherent to rivers, and in the period of low flows — to lakes and reservoirs. Large-scale interference in the ecosystem of Ob-Taz estuarine area recently requires regular hydrological-ecological observations at coastal stations and along the water area sections.

Water mass characteristics in the Makassar Strait and Flores Sea in August-September 2015

Makassar Strait is one of the main entrance points for Indonesian Throughflow (ITF), which carries water from the North Pacific through Flores Sea. ITF has a crucial role as a branch of the thermohaline circulation system in controlling the Indonesian marine ecosystem as well as regional climate variability. This research aims to describe the structure and stratification of water mass and the distribution parameters of chemical physics in the area of Makassar Strait up to Flores Sea at the month of August-September 2015 as much as 8 casts of data CTD is obtained from the result of expedition STOKAS BRKP-KKP using research vessel Baruna Jaya VIII. Research results indicate that the origin of the water mass from the North Pacific is still dominant in the thermocline layer (NPSW) also in the intermediate (NPIW). On average the depth of mixed water layers 60m (± 12.59) with temperature variation between 25.62 – 27.65 C, the average depth of thermocline 130m (±43.65) with temperatures between 18.29 °C – 21.88 °C. Temperature, pH, and dissolved oxygen distribution tends to be higher in the northern region. Fluorescence distribution in the south is higher than the northern region due to inputs from the Makassar upwelling.

Advanced Computational Fluid Dynamics Study of the Dissolved Oxygen Concentration within a Thin-Layer Cascade Reactor for Microalgae Cultivation

High concentration of dissolved oxygen within microalgae cultures reduces the performance of corresponding microalgae cultivation system (MCS). The main aim of this study is to provide a reliable computational fluid dynamics (CFD)-based methodology enabling to simulate two relevant phenomena governing the distribution of dissolved oxygen within MCS: (i) mass transfer through the liquid–air interface and (ii) oxygen evolution due to microalgae photosynthesis including the inhibition by the same dissolved oxygen. On an open thin-layer cascade (TLC) reactor, a benchmark numerical study to assess the oxygen distribution was conducted. While the mass transfer phenomenon is embedded within CFD code ANSYS Fluent, the oxygen evolution rate has to be implemented via user-defined function (UDF). To validate our methodology, experimental data for dissolved oxygen distribution within the 80 meter long open thin-layer cascade reactor are compared against numerical results. Moreover, the consistency of numerical results with theoretical expectations has been shown on the newly derived differential equation describing the balance of dissolved oxygen along the longitudinal direction of TLC. We argue that employing our methodology, the dissolved oxygen distribution within any MCS can be reliably determined in silico, and eventually optimized or/and controlled.

Study on Sludge and Dissolved Oxygen Distribution in a Full-Scale A2/O Oxidation Ditch

The distribution of velocity, sludge, and dissolved oxygen in a full-scale anaerobic-anoxic-oxic (A2/O) oxidation ditch was numerically simulated under three rotation speed scenarios. The viscosity and settling rate of activated sludge were defined through a user-defined function (UDF), and the sludge phase was calculated using the mixture multiphase flow model. Dissolved oxygen (DO) was set as a user-defined source (UDS) and its generation and consumption rates were defined with UDFs. The relationship between velocity and sludge concentration was found to be contradictory, with dead zones leading to large sludge concentrations at the bottom of the oxidation ditch (OD), but not at the middle-curved wall of the anoxic pool. The flow rate of the reflux slot and aerator oxygenation rate were checked and correlated with DO concentrations in the anaerobic pool. The majority of the large sludge concentrations were concentrated in the biological selection pool and these remained constant with bed height. With reduced propeller and agitator rotation speed, the sludge concentrations reduced in the biological selection pool, but increased in the anaerobic and anoxic pools.

Simulation of future dissolved oxygen distribution in pond culture based on sliding window-temporal convolutional network and trend surface analysis

Dissolved oxygen (DO) is a key ecological factor to measure the quality of water in the aquaculture. As the pond water body is affected by the breeding environment, the spatial distribution of DO shows a certain law in the entire pond. Therefore, to simulate the distribution of DO in aquaculture waters and grasp the temporal and spatial variation of DO is the key to achieving precise regulation of DO. For this purpose, this paper proposed a method for simulating the temporal and spatial distribution of DO in pond culture based on a sliding window-temporal convolutional network together with trend surface analysis (SW-TCN-TSA). This paper first utilized SW to construct DO data sets with different prediction durations, and then used the improved TCN model to realize one-dimensional time series prediction for DO at single monitoring point. Based on the prediction results of DO, a TSA method was performed on the predicted values of DO at the extreme moments of all discrete monitoring points, so as to realize the simulation of the temporal and spatial distribution of DO in the pond. Experimental results show that the SW-TCN model has better prediction performance for one-dimensional time series prediction of DO. Compared with traditional deep networks, such as CNN, GRU, LSTM, CNN-GRU and CNN-LSTM, the values of evaluation indicators (MSE, MAE and RMSE) have been greatly improved. In the process of trend surface fitting, all fitting R2 of DO at different water depths are higher than 0.9, indicating that the TSA can accurately reflect the temporal and spatial distribution of DO. This method can provide a basis for the prediction and early warning of DO in the three-dimensional space of the pond and has high practicability in aquaculture.

Effects of Different Water Stratification on the Vertical Distribution of Nitrogen in Sediment Interstitial Waters: A Case Study of the Three Gorges Reservoir and Xiaowan Reservoir

To determine the reasons for the variation in the vertical distribution of nitrogen in sediment interstitial waters between different stratified reservoirs, the characteristics of overlying water-interstitial water in Xiangxi Bay, Yangtze River mainstream, and Xiaowan Reservoir were monitored. The vertical distribution of nitrogen in sediment interstitial waters in these different stratified waters were then analyzed, and the reasons for the variation in this distribution were assessed. The results showed:① the ρ(TN) in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay gradually increased with depth, while that of Xiaowan Reservoir reached its maximum at 12 cm and the bottom layer presented a "C" distribution. The ρ(NH4+) in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay exhibited an increasing trend with depth, while that of Xiaowan Reservoir was slightly higher in the bottom layer than in the surface layer, although the change with depth was not significant. Overall, the ρ(NH4+) in the sediment interstitial waters of the Yangtze River mainstream and Xiangxi Bay was higher than that of Xiaowan Reservoir, and the concentration ranges were as follows:0.512-8.289 mg·L-1, 0.968-9.307 mg·L-1, and 0.950-1.450 mg·L-1. The vertical distribution of the ρ(NO3-) in the sediment interstitial waters of all three waterbodies were opposite to that of ρ(NH4+). Moreover, the ρ(NO3-) in the sediment interstitial waters of Xiangxi Bay and the Yangtze River mainstream was higher than that of Xiaowan Reservoir. The concentration ranges were as follows:0.143-0.674 mg·L-1, 0.107-0.647 mg·L-1, and 0.050-0.051 mg·L-1. ② There were also significant differences in the vertical distribution of physical and chemical indices in the three water bodies. There was no significant change in the vertical distribution of the water temperature in the Yangtze River mainstream and the N2 value was <5×10-5 s-2; hence, the water was well mixed, and the vertical range of the dissolved oxygen content was 6.180-6.318 mg·L-1. The water temperature in the upper and middle reaches of Xiangxi Bay decreased vertically, while the water temperature in the lower reach presented a ladder-like distribution and the N2 values were all>5×10-5 s-2; thus, the water was in a stable stratified state and the dissolved oxygen content presented a "C" distribution. There was obvious stratification at the depths of 5-15 m and 54-70 m in Xiaowan Reservoir. The dissolved oxygen content decreased significantly at higher water temperature gradients, and there was no significant change along the water depth below 80 m. ③ The main reasons for the variation in the vertical distribution of nitrogen in the sediment interstitial waters of the three waterbodies were the differences in the overlying water hydrodynamics, dissolved oxygen distribution, and sediment environment. The ρ(NH4+) and ρ(NO3-) were higher in Xiangxi Bay, which may have increased the denitrification rate and subsequently have helped to remove nitrogen and reduce the nitrogen load in these waters.

Suboxic and anoxic conditions in the Gdansk basins’ deep water (the Baltic sea)

Variability of oxygen and hydrogen sulphide concentrations in the Gdansk basins deep water of the Baltic Sea for the last 25 years was analyzed. It was shown that suboxic and anoxic conditions in deep water were mainly determined by Baltic inflow frequency and intensity. Oxygen concentration in the bottom layer of the Gdansk basins increased strongly in 13 months after Major Baltic Inflow events (MBI). There were three periods of strong increasing of dissolve oxygen concentration in deep water since 1992 till 2018 after MBI in 1993, in 2003 and 20142016. It was shown that at the bottom of the Gdansk basins hydrogen sulphide was detected during 79 months till 22.5 years after MBI. Quality evaluation of dissolved oxygen distribution reanalysis was also conducted in this work. It can be noted good reproduction of field data by the reanalysis in its quality part; however, in most cases the observable maximum concentrations in dissolved oxygen distribution are understated, sometimes even several times.

Numerical simulation of the hydrodynamic behavior and the synchronistic oxidation and reduction in an internal circulation micro-electrolysis reactor

The filter packing of traditional iron–carbon micro-electrolysis reactors is prone to hardening and passivation during operation. In this study, internal loop airlift reactors were used to contain iron–carbon fillings in order to solve these problems and realize a synchronistic oxidation and reduction environment in an internal circulation micro-electrolysis (ICE) reactor. The hydrodynamics of the novel gas–liquid–solid three-phase reactor were investigated through a computational approach. A 2D and 3D transient Eulerian–Eulerian multiphase model was carried out with the standard k − ε turbulence model. Important design parameters of the ICE reactor were identified: the solid velocity, radial profiles of the axial gas holdup and water distribution. The effects of the mesh grid size sensitivity, superficial gas velocity, riser diameter (Dr), height–diameter ratio (H/D), draft tube axial height (Hd) and number of water distribution pipes were considered. The key observations were as follows. The minimum fluidization velocity was 1 m·s−1. With the increase in the number of distribution pipes, the distribution of water was more uniform, but the solid flow resistance increased. When Dr = 30 mm, H/D = 4:1, Hd = 90 mm, and the number of distribution pipes was 4, the hydrodynamic performance was observed to be better. The dissolved oxygen distribution was simulated based on the optimum structural parameters. The experimental results have the same trend as the simulation results, and synchronistic oxidation and reduction was verified in the ICE reactor. Therefore, the optimum structural design and operating parameters and the three-phase system theory were obtained through the CFD simulation, and these findings will provide a basis for the design and enlargement of the ICE reactor.

S-type Dissolved Oxygen Distribution along Water Depth in a Canyon-shaped and Algae Blooming Water Source Reservoir: Reasons and Control.

Dissolved oxygen (DO) is a crucial indicator of water quality. DO usually shows a monotonic decrease along water depth during thermal stratification in reservoir, whereas metalimnetic oxygen minimum (MOM) is observed in some cases. Although MOM phenomena have been reported in different areas, the characteristics of different reservoirs are greatly different, and few comprehensive studies have been published regarding MOM in Chinese drinking water source reservoirs. The DO distribution along water depth was determined and the detailed reasons were clarified by two-years of field monitoring. In addition the effect of water lifting aerators (WLAs) on DO improvement was investigated in the Lijiahe Reservoir in Northwest China. A typical S-type DO distribution with two anaerobic water layers, below the epilimnion (10–25 m water depth) and above the sediment (bottom water), was observed derived from the decomposition of dead algae or organic matter and the restriction of DO vertical exchange. Moreover, after WLAs’ operation since 10 June 2018, the water body was completely mixed and DO was rich and uniform along water depth by eliminating the water stratification and inhibiting algae growth. The deep understanding of the DO distribution in a deep canyon-shaped reservoir and the technical support for reservoir restoration are meaningful for optimizing reservoir management.

Monitoring gradient formation in a jet aerated bioreactor.

Jet aerated loop reactors (JLRs) provide high mass transfer coefficients (kLa) and can be used for the intensification of mass transfer limited reactions. The jet loop reactor achieves higher kLa values than a stirred tank reactor (STR). The improvement relies on significantly higher local power inputs (∼104) than those obtainable with the STR. Operation at high local turnover rates requires efficient macromixing, otherwise reactor inhomogeneities might occur. If sufficient homogenization is not achieved, the selectivity of the reaction and the respective yields are decreased. Therefore, the balance between mixing and mass transfer in jet loop reactors is a critical design aspect. Monitoring the dissolved oxygen levels during the turnover of a steady sodium sulfite feed implied the abundance of gradients in the JLR. Prolonged mixing times at identical power input and aeration rates (∼100%) were identified for the JLR in comparison to the STR. The insertion of a draft tube to the JLR led to a more homogenous dissolved oxygen distribution, but unfortunately a reduction of mixing time was not achieved. In case of increased medium viscosities as they may arise in high cell density cultivations, no gradient formation was detected. However, differences in medium viscosity significantly altered the mass transfer and mixing performance of the JLR.

The Effect of Dissolved Oxygen Distribution on Ammonium Nitrogen Removal in a Pilot-Scale of Vertical Upward-Flow of Aerated Electric Arc Furnace Slag Filter Systems At Various Hydraulic Loading Rates

The performance of an aerated vertical upward-flow electric arc furnace slag filter (VFEAFS) system in treating domestic wastewater was examined in a warm-climate country temperature. Two pilot scale column experiments were conducted at high (2.72 m3/m3.day) and low (1.04 m3/m3.day) hydraulic loading rate (HLR) set-up and the effect of different hydraulic loading levels on pollutant removal efficiency were studied. Aeration was introduced in the filter system at 10 L/min to observe oxygen distribution concentration towards ammonium nitrogen removal. The results demonstrated that both HLR set-up were capable to achieve more than 90% ammonium nitrogen (AN) removal; however, in terms of individual efficiency of the filter system, the VFEAFS of lower HLR performed better in comparison to the higher HLR set-up. The average effluent concentration of AN by both systems were found far below standard A of Malaysian sewage discharge limit (10 mg NH4-N/L). The results achieved in this pilot scale study indicate that removal of ammonium nitrogen in the aerated VFEAFS was explained by nitrification process, and this treatment system could be implemented to the other industry-environmental, municipal or residential wastewater.

Some characteristics of the new reservoir of Platanovrysi that affect the river Nestos system

The reservoir of Platanovrysi in the Nestos valley has a long and narrow shape, limited in area and volume, deep close to the dam wall (90 m) and very shallow at its uphill end (5m). It receives considerable volume of water from the upper large reservoir of Thesaurus all through the year, as well as limited volumes of water in seasonal flows from its drainage basin. Platanovrysi reservoir has distinct morphological and operational characteristics that make it different from natural lakes regarding temperature and dissolved oxygen distribution in the water column. The epilimnion is limited at the area of the deeper part of the lake only. It forms an entrapped warm wedge, with the maximum depth close to the dam and a horizontal extension up to the beginning of the shallow part of the lake. This is due to both the inflows of large volumes of cold water from Thesaurus as well as the lack of a surface outflow from the dam of Platanovrysi. The water temperatures of the surface water of the upper part of the lake as well as the temperatures of the hypolimnion are similar. The temperature is very low during the spring and the summer (6-7°C), becomes higher during autumn (14-15°C) and drops again during winter (9-10°C). This shifting of seasonal temperatures is purely due to the inflows of cold water from the hypolimnion of the reservoir of Thesaurus in spring and summer periods and from the base of epilimnion during autumn. The water is rich in oxygen during the spring and the summer while it becomes poor in oxygen during the autumn and the beginning of winter. The operation of Platanovrysi Power Station allows the cold water from the hypolimnion of the lake to flow into the river Nestos channel and brings cold water during the warm period of the year downstream. This type of change of the water temperature may affect the natural processes of the river fauna and flora as well as the human processes in the plains of Nestos (irrigation). It is therefore necessary to construct and operate the last (lower) reservoir of Temenos in Nestos, to regulate the flow and warm the water of the river Nestos channel.

Prediction model of dissolved oxygen in ponds based on ELM neural network

Dissolved oxygen in ponds is affected by many factors, and its distribution is unbalanced. In this paper, in order to improve the imbalance of dissolved oxygen distribution more effectively, the dissolved oxygen prediction model of Extreme Learning Machine (ELM) intelligent algorithm is established, based on the method of improving dissolved oxygen distribution by artificial push flow. Select the Lake Jing of Guangxi University as the experimental area. Using the model to predict the dissolved oxygen concentration of different voltage pumps, the results show that the ELM prediction accuracy is higher than the BP algorithm, and its mean square error is MSEELM=0.0394, the correlation coefficient RELM=0.9823. The prediction results of the 24V voltage pump push flow show that the discrete prediction curve can approximate the measured values well. The model can provide the basis for the artificial improvement of the dissolved oxygen distribution decision.

Evidence from field measurements and satellite imaging of impact of Earth rotation on Lake Iseo chemistry

Abstract During an initial field survey in 2012, we observed an unexpected asymmetry of dissolved oxygen distribution between the western and eastern side in northern Lake Iseo. Motivated by this apparent anomaly, we conducted a detailed field investigation, and we used a physical model of the northern part of the lake to understand the influences that might affect the distribution of material in the northern section of the lake. These investigations suggested that the Earth's rotation has significant influence on the inflow of the lake's two main tributaries. In order to further crosscheck the validity of these results, we conducted a careful analysis at a synoptic scale using images acquired during thermally unstratified periods by Landsat-8 and Sentinel-2 satellites. We retrieved and post-processed a large set of images, providing conclusive evidence of the role exerted by the Earth's rotation on pollutant transport in Lake Iseo and of the greater environmental vulnerability of the north-west shore of this lake, where important settlements are located. Our study confirms the necessity for three-dimensional hydrodynamic models including Coriolis effect in order to effectively predict local impacts of inflows on nearshore water quality of medium-sized elongated lakes of similar scale to Lake Iseo.