scholarly journals Diurnal dynamics of dissolved oxygen in the small mesotrophic lake during the under-ice heating period

2019 ◽  
Vol 151 (4) ◽  
pp. 27-39
Author(s):  
N. I. Palshin ◽  
T. V. Efremova ◽  
G. E. Zdorovennova ◽  
G. G. Gavrilenko ◽  
R. E. Zdorovennov ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Heating Period ◽  
Total Oxygen ◽  
Convective Mixing ◽  
Ice Surface ◽  
Irradiation Growth ◽  
Mesotrophic Lake ◽  
Daily Frequency ◽  
Do Concentration

The article investigates the dynamics of the dissolved oxygen (DO) content, the water temperature, the chlorophyll «a» and the under-ice irradiation in the small mesotrophic lake during the springtime heating period. All data were obtained from long-term observations using high-precision autonomous equipment. In the convectively mixed layer (CML) were recorded the DO oscillations up to 1 mgO2/l with daily frequency. Assumedly, these fluctuations are due to the daytime intensification of the photosynthesis on the background of under-ice irradiation growth (reaching 120 W/m2 when snow melts from ice surface) and the destruction of newly formed organic matter. The CML also exhibits the high-frequency DO fluctuations (on scales from 2—3 minutes to 3—4 hours), presumably related to convective currents and seiche activity. The involvement of oxygen-depleted water portions from underlying stratified layer to convective mixing leads to decrease of DO concentration in CML, but the total oxygen content in the water column during the under-ice convection period increases at a rate ~0.1—0.4 gO2/m2 per day due to photosynthesis enhance.

scholarly journals Dissolved oxygen stratification in a small lake depending on water temperature and density and wind impact

2021 ◽  
Vol 937 (3) ◽  
pp. 032019
Author(s):  
N Palshin ◽  
G Zdorovennova ◽  
T Efremova ◽  
S Bogdanov ◽  
A Terzhevik ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Water Temperature ◽  
Wind Load ◽  
Density Stratification ◽  
Wind Regime ◽  
Independent Variables ◽  
Decomposition Of Organic Matter ◽  
Do Concentration ◽  
Weak Stratification

Abstract The dissolved oxygen (DO) is one of the most important parameters in lakes ecosystem. Variability of DO in lakes is associated with the absorption of oxygen due to the decomposition of organic matter and chemical reactions and the release of oxygen as a result of photosynthesis. The DO concentration also depends on seasonal changes in water temperature and mixing regime. The aim of this work is to assess the influence of seasonal thermal and density stratification on the DO stratification in a small mesotrophic lake and to develop a regression DO model, with water temperature and density and characteristics of wind regime as independent variables. Long-term measurements of water temperature and DO in small Karelian Lake Vendyurskoe in 2007-2020 were used. At the stage of spring-summer heating, three periods are considered when the water column was in the state of homothermy (May 15-June 15), weak stratification (July 15-August 15), and strong stratification (July 15-August 15). The wind load (number of days with wind speed more than 3 m/s for each period) was analysed based on the weather station Petrozavodsk data. As a result of multiple regression analysis, taking into account the wind load, dependences of DO stratification on water temperature stratification (R2 = 0.51) and water density stratification (R2 = 0.61) are found. Obtained regression DO models can be used for solving various environmental tasks.

scholarly journals Electron generation in water induced by magnetic effect and its impact on dissolved oxygen concentration

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Augustine Chung Wei Yap ◽  
Hwang Sheng Lee ◽  
Joo Ling Loo ◽  
Nuruol Syuhadaa Mohd
Keyword(s):  
Water Quality ◽  
Hydrogen Bonding ◽  
Dissolved Oxygen ◽  
Electron Density ◽  
Water Flow ◽  
Magnetic Effect ◽  
Water Quality Control ◽  
Electron Generation ◽  
Magnetic Effects ◽  
Do Concentration

AbstractpH, oxidation-reduction potential (ORP) and dissolved oxygen (DO) concentration are important parameters in water quality surveillance and treatment. The changes of these parameters are associated with electron density in water. Several techniques including electrolysis and catalysis which require redox reactions and electron exchange are employed to improve these parameters. In recent years, studies reported that magnetic effects can impart considerable changes on the pH, ORP and DO concentration of water. However, the correlation between electron density and magnetic effects on these parameters has yet to be disclosed despite the fact that increased electron density in water could improve water’s reductive properties, heat capacity and hydrogen bonding characteristics. In this study, the magnetic effects on pH, ORP and DO concentration were investigated using different magnets arrangements and water flow rates based on reversed electric motor principle. Results showed that the improvement of pH, ORP and DO concentration from 5.40–5.42 to 5.58–5.62 (+ 3.5%), 392 to 365 mV (− 6.9%), and 7.30 to 7.71 mg L− 1 (+ 5.6%), respectively were achieved using combined variables of non-reversed polarity magnet arrangement (1000–1500 G magnetic strength) and water flow rate of 0.1–0.5 mL s− 1. Such decrement in ORP value also corresponded to 8.0 × 1013 number of electron generation in water. Furthermore, Raman analysis revealed that magnetic effect could strengthen the intermolecular hydrogen bonding of water molecules and favor formation of smaller water clusters. The findings of this study could contribute to potential applications in aquaculture, water quality control and treatment of cancer attributed to free radical induced-oxidative stress.

scholarly journals Limnology of Merbok estuary, Kedah, Malaysia

2015 ◽  
Vol 41 (1) ◽  
pp. 13-19
Author(s):  
Kaniz Fatema ◽  
Wan Maznah Wan Omar ◽  
Mansor Mat Isa
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
The Other ◽  
Wet Season ◽  
Hand Temperature ◽  
Do Concentration ◽  
Merbok Estuary

Water quality in three different stations of Merbok estuary was investigated limnologically from October, 2010 to September, 2011. Water temperature, transparency and total suspended solids (TSS) varied from 27.45 - 30.450C, 7.5 - 120 cm and 10 -140 mg/l, respectively. Dissolved Oxygen (DO) concentration ranged from 1.22-10.8 mg/l, while salinity ranged from 3.5-35.00 ppt. pH and conductivity ranged from 6.35 - 8.25 and 40 - 380 ?S/cm, respectively. Kruskal Wallis H test shows that water quality parameters were significantly different among the sampling months and stations (p<0.05). This study revealed that DO, salinity, conductivity and transparency were higher in wet season and TSS was higher in dry season. On the other hand, temperature and pH did not follow any seasonal trends.Bangladesh J. Zool. 41(1): 13-19, 2013

Reoxygenation Rate for Airlift Inner Circulation Reactor

2013 ◽  
Vol 726-731 ◽  
pp. 1926-1929
Author(s):  
Ke Wu Pi ◽  
Min Xia ◽  
Shi Shi ◽  
Qu Xiao
Keyword(s):  
Dissolved Oxygen ◽  
Aeration Rate ◽  
Airlift Reactor ◽  
Liquid Level ◽  
Aeration Tank ◽  
Do Concentration

Airlift inner circulation reactor (AICR) consisting of beaker and built-in aeration tank was introduced in this paper. The Dissolved oxygen recovery (RDO) was highly influenced by the ratios of the height of built-in aeration tank to the height of liquid level in reactor (Rh/H), the diameter of built-in aeration tank to the diameter of the reactor (Rd/D) and aeration rate (QN). Average RDO of 24.25 m.gm-3.s-s and DO concentration of 8.97mg.l-1 were obtained at Rd/D=0.47, Rh/H=0.68 and QN =1.0m3.m-3.min-1 for aerating 370s at 17°C. The total transferred oxygen in 4L deoxidized water reached 35.89mg, which had an increase by 11.15% than that of the traditional airlift reactor (AR). The DO concentration was 88.33-9.34mg.l-1 for AICR, but it’s only 7.71-8.58mg.l-1 for AR.

scholarly journals Qualified temperature, salinity and dissolved oxygen climatologies in a changing Adriatic Sea

2014 ◽  
Vol 11 (1) ◽  
pp. 331-390
Author(s):  
M. Lipizer ◽  
E. Partescano ◽  
A. Rabitti ◽  
A. Giorgetti ◽  
A. Crise
Keyword(s):  
Dissolved Oxygen ◽  
Adriatic Sea ◽  
Eastern Mediterranean ◽  
Temporal Stability ◽  
The South ◽  
The North ◽  
Synthetic Temperature ◽  
Oxygen Utilisation ◽  
Oxygen Minimum

Abstract. An updated climatology, based on a comprehensive dataset (1911–2009) of temperature, salinity and dissolved oxygen, has been produced for the whole Adriatic Sea with the Variational Inverse Method using the DIVA software. Climatological maps were produced at 26 levels and validated with Ordinary Cross Validation and with real vs. synthetic Temperature–Salinity diagram intercomparison. The concept of Climatology–Observation Misfit (COM) has been introduced as an estimate of the physical variability associated with the climatological structures. In order to verify the temporal stability of the climatology, long-term variability has been investigated in the Mid Adriatic and the South Adriatic Pits, regarded as the most suitable records of possible long-term changes. Compared with previous climatologies, this study reveals a surface temperature rise (up to 2 °C), a clear deep dissolved oxygen minimum in the South Adriatic Gyre and a bottom summer oxygen minimum in the North Adriatic. Below 100 m all properties profoundly differ between the Middle and the South Adriatic. The South Adriatic Pit clearly shows the remote effects of the Eastern Mediterranean Transient, while no effect is observed in Middle Adriatic Pits. The deepest part of the South Adriatic seems now to be significantly saltier (+0.18 since the period 1911–1914, with an increase of +0.018 decade−1 since the late 1940s) and warmer (+0.54 °C since 1911–1914), even though a long-term temperature trend could not be statistically demonstrated. Conversely, the Middle Adriatic Pits present a long-term increase in apparent oxygen utilisation (+0.77 mL L−1 since 1911–1914, with a constant increase of +0.2 mL L−1 decade−1 after the 1970s).

scholarly journals Are longitudinal ice-surface structures on the Antarctic Ice Sheet indicators of long-term ice-flow configuration?

2014 ◽  
Vol 2 (2) ◽  
pp. 911-933 ◽  
Author(s):  
N. F. Glasser ◽  
S. J. A. Jennings ◽  
M. J. Hambrey ◽  
B. Hubbard
Keyword(s):  
Flow Line ◽  
Ice Sheet ◽  
Surface Structures ◽  
Surface Velocity ◽  
Ice Flow ◽  
Antarctic Ice Sheet ◽  
Ice Surface ◽  
Ice Stream ◽  
The Antarctic

Abstract. Continent-wide mapping of longitudinal ice-surface structures on the Antarctic Ice Sheet reveals that they originate in the interior of the ice sheet and are arranged in arborescent networks fed by multiple tributaries. Longitudinal ice-surface structures can be traced continuously down-ice for distances of up to 1200 km. They are co-located with fast-flowing glaciers and ice streams that are dominated by basal sliding rates above tens of m yr-1 and are strongly guided by subglacial topography. Longitudinal ice-surface structures dominate regions of converging flow, where ice flow is subject to non-coaxial strain and simple shear. Associating these structures with the AIS' surface velocity field reveals (i) ice residence times of ~ 2500 to 18 500 years, and (ii) undeformed flow-line sets for all major flow units analysed except the Kamb Ice Stream and the Institute and Möller Ice Stream areas. Although it is unclear how long it takes for these features to form and decay, we infer that the major ice-flow and ice-velocity configuration of the ice sheet may have remained largely unchanged for several thousand years, and possibly even since the end of the last glacial cycle. This conclusion has implications for our understanding of the long-term landscape evolution of Antarctica, including large-scale patterns of glacial erosion and deposition.

scholarly journals Two independent methods for mapping the grounding line of an outlet glacier – example from the Astrolabe Glacier, Terre Adélie, Antarctica

2013 ◽  
Vol 7 (4) ◽  
pp. 3969-4014
Author(s):  
E. Le Meur ◽  
M. Sacchettini ◽  
S. Garambois ◽  
E. Berthier ◽  
A. S. Drouet ◽  
...  
Keyword(s):  
Control Points ◽  
Gps Measurements ◽  
Outlet Glacier ◽  
Ice Surface ◽  
Surface Displacements ◽  
Grounding Line ◽  
Terre Adélie ◽  
Elastic Slab ◽  
Kinematic Approach

Abstract. The grounding line is a key element acting on the dynamics of coastal outlet glaciers. Knowing its position accurately is fundamental for both modelling the glacier dynamics and establishing a benchmark to which one can later refer in case of change. Here we map the grounding line of the Astrolabe Glacier in East Antarctica (66°41´ S; 140°05´ E), using hydrostatic and tidal methods. The first method is based on new surface and ice thickness data from which the line of buoyant flotation is found. We compare this hydrostatic map with kinematic GPS measurements of the tidal response of the ice surface. By detecting the transitions where the ice starts to move vertically in response to the tidal forcing we find control points for the grounding line position along GPS profiles. %If it can be shown that the long-term viscous mechanical behaviour of the ice slab validates the hydrostatic approach, mapping the grounding line from the ice supper surface displacements conversely requires correcting for the rigid elastic slab effect that dominates at tidal frequencies. With the help of a 2-dimensional elastic plate model, rigid elastic deviations are computed and applied to these control points. Once the extent of the grounding zone, the kinematic approach is consistent with the hydrostatic map. These two approaches lead us to propose a grounding line for the Astrolabe Glacier that significantly deviates from those obtained so far from satellite imagery.

scholarly journals Electron generation in water induced by magnetic effect and its impact on dissolved oxygen concentration

2021 ◽  
Author(s):  
Augustine Chung Wei Yap ◽  
Hwang Sheng Lee ◽  
Joo Ling Loo ◽  
Nuruol Syuhadaa Mohd
Keyword(s):  
Water Quality ◽  
Hydrogen Bonding ◽  
Dissolved Oxygen ◽  
Electron Density ◽  
Water Flow ◽  
Magnetic Effect ◽  
Water Quality Control ◽  
Electron Generation ◽  
Magnetic Effects ◽  
Do Concentration

Abstract pH, oxidation-reduction potential (ORP) and dissolved oxygen (DO) concentration are important parameters in water quality surveillance and treatment. The changes of these parameters are associated with electron density in water. Several techniques including electrolysis and catalysis which require redox reactions and electron exchange are employed to improve these parameters. In recent years, studies reported that magnetic effects can impart considerable changes on the pH, ORP and DO concentration of water. However, the correlation between electron density and magnetic effects on these parameters has yet to be disclosed despite the fact that increased electron density in water could improve water’s reductive properties, heat capacity and hydrogen bonding characteristics. In this study, the magnetic effects on pH, ORP and DO concentration were investigated using different magnets arrangements and water flow rates based on reversed electric motor principle. Results showed that the improvement of pH, ORP and DO concentration from 5.40–5.42 to 5.58–5.62 (+ 3.5%), 392 to 365 mV (-6.9%), and 7.30 to 7.71 mg L− 1 (+ 5.6%), respectively were achieved using combined variables of non-reversed polarity magnet arrangement (1000–1500 G magnetic strength) and water flow rate of 0.1–0.5 mL s− 1. Such decrement in ORP value also corresponded to 8.0 × 1013 number of electron generation in water. Furthermore, Raman analysis revealed that magnetic effect could strengthen the intermolecular hydrogen bonding of water molecules and favor formation of smaller water clusters. The findings of this study could contribute to potential applications in aquaculture, water quality control and treatment of cancer attributed to free radical induced-oxidative stress.

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