scholarly journals Limnological Comparisons of Threats to Aquatic Life Owing to Thermal Stratification in two Morphometrically Different Urban Shallow Lakes

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Nihar R. Samal ◽  
Pankaj K. Roy ◽  
Malabika B. Roy ◽  
Asis Mazumdar Mazumdar
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Shallow Lakes ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Daily Basis ◽  
Tropical Lakes ◽  
Aquatic Life ◽  
Delta Plain ◽  
The Impact

A minimum value in the Dissolved Oxygen distribution of two shallow lakes namely, Rabindra Sarobar in south Kolkata and Subhas Sarobar in East Kolkata in the Gangetic Delta plain, has been observed to develop in the Hypolimnion during the stratified period. This minimum is usually explained by the accumulation of organic matter from the overlying layer of water. The introduction of organic matter from allochthonous and autochthonous sources is also a likely contributor to the accelerated oxygen depletion within Hypolimnion. The thermal stratification, in general, which occurs in these tropical lakes, is of direct relevance in maintaining the water quality standards, particularly for higher aquatic life. The present article attempts to investigate the possible depletion of hypolimnetic oxygen depletion as a result of the impact of thermal stratification.  These investigations will be the basic guidelines for the fishermen and their livelihoods potentially depend upon the different varieties of fishing on daily basis. The massive summer fish kills in these lakes is a major devastating happenings that is reported by the fishermen and also it is well evident from our experimental observations.  The comparison of the biodiversity of these two lakes is attempted in the present investigation. Key Words: Thermal stratification, Dissolved Oxygen, Tropical Shallow Lake, Hypolimnion, biodiversity

scholarly journals Impact of Global Warming on Dissolved Oxygen and BOD Assimilative Capacity of the World’s Rivers: Modeling Analysis

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2408
Author(s):  
Steven C. Chapra ◽  
Luis A. Camacho ◽  
Graham B. McBride
Keyword(s):  
Dissolved Oxygen ◽  
Natural Waters ◽  
Cold Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Assimilative Capacity ◽  
Mountainous Regions ◽  
Modeling Analysis ◽  
Lower Oxygen ◽  
The Impact

For rivers and streams, the impact of rising water temperature on biochemical oxygen demand (BOD) assimilative capacity depends on the interplay of two independent factors: the waterbody’s dissolved oxygen (DO) saturation and its self-purification rate (i.e., the balance between BOD oxidation and reaeration). Although both processes increase with rising water temperatures, oxygen depletion due to BOD oxidation increases faster than reaeration. The net result is that rising temperatures will decrease the ability of the world’s natural waters to assimilate oxygen-demanding wastes beyond the damage due to reduced saturation alone. This effect should be worse for nitrogenous BOD than for carbonaceous BOD because of the former’s higher sensitivity to rising water temperatures. Focusing on streams and rivers, the classic Streeter–Phelps model was used to determine the magnitude of the maximum or “critical” DO deficit that can be calculated analytically as a function of the mixing-point BOD concentration, DO saturation, and the self-purification rate. The results indicate that high-velocity streams will be the most sensitive to rising temperatures. This is significant because such systems typically occur in mountainous regions where they are also subject to lower oxygen saturation due to decreased oxygen partial pressure. Further, they are dominated by salmonids and other cold-water fish that require higher oxygen levels than warm-water species. Due to their high reaeration rates, such systems typically exhibit high self-purification constants and consequently have higher assimilation capacities than slower moving lowland rivers. For slow-moving rivers, the total sustainable mixing-point concentration for CBOD is primarily dictated by saturation reductions. For faster flowing streams, the sensitivity of the total sustainable load is more equally dependent on temperature-induced reductions in both saturation and self-purification.

Studies of the hydrobiology of a tropical lake in north-western Queensland. II. Seasonal changes in thermal and dissolved oxygen characteristics

1980 ◽  
Vol 31 (5) ◽  
pp. 589 ◽  
Author(s):  
CM Finlayson ◽  
TP Farrell ◽  
DJ Griffiths
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Environmental Conditions ◽  
Seasonal Changes ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Tropical Lake ◽  
North Western

The stratification characteristics of Lake Moondarra (24�34'S.,139�35'E.), a man-made lake in north- western Queensland, have been studied. Evidence is presented that the lake approximates the warm polymictic type in which no persistent thermal stratification ever develops. During the cooler months, thermal stratification breaks down during the night; in the warmer months, the intense rainstorms prevent the establishment of a persistently stratified water column. The shallowness of the lake relative to its surface areaand the prevailing environmental conditions ensure that extensive periods of oxygen depletion do not develop in the water column. It is concluded that a strong and prolonged period of thermal stratification, with subsequent serious effects of the availability of dissolved oxygen in the deeper layers, would only arise if, in a particular year. there were no significant rainstorms.

scholarly journals The Relationship between Mollusks and Oxygen Concentrations in Todos Santos Bay, Baja California, Mexico

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
J. Gabriel Kuk-Dzul ◽  
Victoria Díaz-Castañeda
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Bottom Water ◽  
Organic Matter Content ◽  
Oxygen Depletion ◽  
Matter Content ◽  
The Other ◽  
Natural Conditions ◽  
The Relationship ◽  
Oxygen Concentrations

This study describes the relationship between mollusks, physicochemical properties of seawater, and sediments under natural conditions of low impact. Thirty-nine stations were sampled in October 1994 using a Van Veen grab (0.1 m−2). Temperature, salinity, and dissolved oxygen (DO) concentrations of bottom water were obtained with a CTD. Organic matter content and sediment grain analysis were determined. A total of 836 mollusks were collected. Gastropoda was the most abundant (52%) and diverse class with 27 genera, followed by Bivalvia with eight genera and Scaphopoda with only one genus. According to CCA analysis, dominant mollusks were significantly related with high DO concentrations.Donax,Natica,Acteocina,Bulla,Anachis,Odostomia, andCrucibulumcan be classified as sensitive genera because they were found mainly in high oxygen concentrations (3.1–5.6 mL L−1); on the other hand,Cardiomya,Nuculana,Laevicardium,Chione,Truncatella, andDentaliumcan be classified as tolerant genera (1.0–5.6 mL L−1). Todos Santos Bay hosts a diverse malacological fauna (36 genera); our results show that the dominant genera were mainly related to high dissolved oxygen concentrations. Mollusks can be a useful tool in environmental monitoring programs related with oxygen depletion in coastal areas.

Impact of dissolved oxygen concentration on membrane filtering resistance and soluble organic matter characteristics in membrane bioreactors

2008 ◽  
Vol 57 (2) ◽  
pp. 161-165 ◽  
Author(s):  
Kyung-Nan Min ◽  
Sarina J. Ergas ◽  
Anna Mermelstein
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Dissolved Oxygen ◽  
Weight Fraction ◽  
Total Resistance ◽  
Soluble Organic Matter ◽  
Aerobic Conditions ◽  
Do Concentration ◽  
The Impact ◽  
Molecular Weight Fractions

This study investigated the impact of dissolved oxygen (DO) concentration on membrane filtering resistance, soluble organic matter (SOM) and extracellular polymeric substance (EPS) characteristics in a membrane bioreactor (MBR). A laboratory-scale MBR was operated under DO limited (0.2 mg L−1 DO) and fully aerobic (3.7 and 5.4 mg L−1 DO) conditions. Membrane filtering resistance was determined for the mixed liquor suspended solids (MLSS) and for resuspended microbial biomass after removing SOM. Regardless of the DO concentration, the cake resistance (Rc) was approximately 95 percent of the total resistance (Rt). The membrane cake resistance was found to decrease significantly after removing the SOM. The total resistance caused by the resuspended biomass was 29 percent of that caused by the MLSS under DO limited conditions, while the total resistance caused by resuspended biomass was 41 to 48 percent of that caused by the MLSS under fully aerobic conditions. Under DO limited conditions, SOM in the MLSS contained a larger amount of high molecular weight compounds, leading to higher cake resistance than under fully aerobic conditions. There was significant variation in the molecular weight fractions of the EPS, with no clear relationship with DO concentration. There was also no distinct relationship between membrane filtering resistance and molecular weight fraction of the EPS.

Aerobic microbial transformations of pipe and silt trap sediments from combined sewers

1999 ◽  
Vol 39 (2) ◽  
pp. 233-249 ◽  
Author(s):  
Jes Vollertsen ◽  
Thorkild Hvitved-Jacobsen ◽  
Iain McGregor ◽  
Richard Ashley
Keyword(s):  
Organic Matter ◽  
Dissolved Oxygen ◽  
Conceptual Model ◽  
Combined Sewer Overflow ◽  
Organic Fraction ◽  
Combined Sewer ◽  
Receiving Waters ◽  
Oxygen Utilisation ◽  
Fast Settling ◽  
The Impact

Organic matter in sediments from pipes and silt traps in combined sewers was divided into fractions with different settling velocities. Biodegradability of organic matter for these fractions was characterised based on results from a conceptual model of aerobic transformations of resuspended sediments calibrated on oxygen utilisation rates. Pipe sediments as well as silt trap sediments were investigated and no differences between these deposits were detected. It was found that the largest fraction of organic matter is associated with material which settles relatively fast and only a small part is associated with relatively slow settling material. However, the fast settling organic matter was found to be rather slowly biodegradable compared to the slow settling organic fraction. Because the biodegradability of the organic matter discharged during combined sewer overflow (CSO) events is of significant importance to the impact on the dissolved oxygen concentrations in receiving waters, the biodegradability of sewer sediments is argued to be taken into account for detailed characterisation when dealing with CSO impacts.

scholarly journals Effects of copper in Daphnia are modulated by nanosized titanium dioxide and natural organic matter: what is the impact of aging duration?

2020 ◽  
Author(s):  
Rajdeep Roy ◽  
Simon Lüderwald ◽  
Asawer Alawi Ahmed Maknoon ◽  
George Metreveli ◽  
Ralf Schulz ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Aquatic Life ◽  
Cu Toxicity ◽  
Nanosized Titanium Dioxide ◽  
Exposure Pathway ◽  
The Impact

AbstractDuring its aquatic life cycle, nanosized titanium dioxide (nTiO2) may interact with natural organic matter (NOM) ultimately altering the ecotoxicity of co-occurring chemical stressors such as heavy metals (e.g. copper (Cu)). In this context, the following hypotheses were tested: (1) aging of nTiO2 along with Cu reduces Cu toxicity, (2) nTiO2 agglomerates have a lower potential to reduce Cu toxicity and (3) aging of nTiO2 in presence of NOM reduces Cu toxicity further. A multifactorial test design crossing three nTiO2 levels (0.0, 0.6 and 3.0 mg/L) with two levels of NOM (0 versus 8 mg total organic carbon (TOC)/L) and seven nominal Cu concentrations (ranging from 0 to 1536 μg/L) aged in ASTM medium for 0, 1, 3 and 6 days was realised, while two aging scenarios were applied (type 1: nTiO2 jointly aged with Cu; type 2: Cu added after nTiO2 aging). Subsequently, Cu toxicity was assessed using the immobility of Daphnia magna after 48 h of exposure as response variable. The experiments revealed that neither aging duration nor the extent of agglomeration (type 1 vs. type 2 aging) has a substantial impact on Cu induced toxicity. Moreover, it was confirmed that the presence of NOM substantially reduced Cu induced toxicity, independent of the aging scenario and duration. More importantly, the data suggest the ingestion of Cu loaded nTiO2 as additional exposure pathway contributing to Cu toxicity. In conclusion, it seems unlikely that nTiO2 concentrations currently detected in or predicted for aquatic ecosystems, which are at least one order of magnitude below the concentration tested here, influence Cu toxicity meaningfully.

scholarly journals Study on the Quality of Water in Some Streams of Cauvery River

2008 ◽  
Vol 5 (2) ◽  
pp. 377-384 ◽  
Author(s):  
Abida Begum ◽  
Harikrishnarai
Keyword(s):  
Dissolved Oxygen ◽  
Small Scale ◽  
Cauvery River ◽  
Aquatic Life ◽  
Discharge Point ◽  
Quality Of Water ◽  
Significant Difference ◽  
Effluent Discharge ◽  
The Impact

The quality of water in four streams of Cauvery River in Mandya District, where many small scale sugar and brewery distilleries are located, was analysed. Sampling was carried out from four streams designated as station 1 (upstream of effluent discharge point), station 2 (effluent discharge point) and station 3 (downstream of effluent discharge) station 4 (fresh water stream) to assess the impact of effluent on the water quality. The river water composition is increasingly dominated by Na and Cl in the downstream region of the river, indicating the influence of airborne salts with oceanic affinities. Significant spatial variation was observed in water level, transparency, turbidity, depth, dissolved oxygen, colour, biochemical oxygen demand, nitrate, nitrite and total hydrocarbon among the physiochemical parameters of the study stations. Aposterioritest revealed that station 2 & 3 were the cause of the significant difference. The dissolved oxygen level in stations 2 & 3 was lower than 5.0mg/L, which is recommended minimum allowable limit for aquatic life. About 7 rotifer species in large amount recorded in this study were encountered in station 1, 7 in station 2 & 3 while 12 species in station 4. The overall density of rotifers in the four stations was significantly different. Aposterioricomparison revealed that station 2 & 3 are the cause of the significant difference. The Branchionus angularis rotifers, which dominated the community, were found to tolerate the effluent effect in station 2&3, and showed remarkable recovery in the downstream station 4. Low faunal diversity and negative impact on the biotic and abiotic environment was experienced in station 2 & 3 throughout the duration of sampling because of the brewery effluent discharged directly into these two Streams.

Dependence of Lake Oxygen Depletion Rates on Maximum Oxygen Storage in a Partially Meromictic Lake in Alberta

1988 ◽  
Vol 45 (3) ◽  
pp. 571-576 ◽  
Author(s):  
Annette M. Trimbee ◽  
E. E. Prepas
Keyword(s):  
Dissolved Oxygen ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Meromictic Lake ◽  
Oxygen Storage ◽  
Lake Productivity ◽  
Lake Mixing ◽  
Hypolimnetic Oxygen

Areal rates of hypolimnetic oxygen depletion (AHOD) and winter oxygen depletion (AWOD) varied considerably from year to year in a partially meromictic lake (Narrow Lake) in central Alberta. AHOD ranged from 0.222 to 0.522 g O2∙m−2∙d−1 over four summers and AWOD ranged from 0.354 to 0.614 g O2∙m−2∙d−1 over three winters. AHOD was positively correlated with maximum storage of dissolved oxygen (O2) at the onset of summer thermal stratification (P < 0.05). Similarly, AWOD was higher in years when mixing was more complete and maximum O2 storage at freeze-up was higher. These results suggest that the prediction of O2 depletion rates for lakes with year-to-year variation in maximum O2 storage can be improved if maximum O2 storage after lake mixing is considered in addition to other factors known to influence O2 depletion rates such as lake productivity and morphometry.

scholarly journals Effect of lead in the aerobic decomposition of Myriophyllum aquaticum (Vellozo) Verdecourt

2020 ◽  
Vol 15 ◽  
pp. 43-49
Author(s):  
B.S. Soares ◽  
I Bianchini Junior ◽  
M.B. Cunha-Santino
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Dissolved Oxygen ◽  
Aquatic Environment ◽  
Toxic Element ◽  
Industrial Processes ◽  
Myriophyllum Aquaticum ◽  
Cycling Rate ◽  
Aerobic Decomposition ◽  
The Impact

Lead is a toxic element that has been used since early times and is still employed today in several industrial processes. Events as the collapse of the Fundão dam in Bento Rodrigues, district of Mariana (MG) on November 2015, significantly increase concentrations of metals above-recommended levels, including lead. In this context, this study aims to evaluate the impact of lead in the cycling rate of organic matter in the aquatic environment. Thus, the rates of aerobic decomposition of Myriophyllum aquaticum (Vell.) Verdec at different concentrations of lead (5.0, 10.0, 20.0 and 30.0 mg L-1) were measured, analyzing the dissolved oxygen consumption. Decomposition chambers filled with samples of water and M. aquaticum were incubated at 20° C in the dark for 80 days and periodically had the oxygen concentrations determined by polarography, when the concentrations were less than 2 mg L-1, the incubations were re-aerated. At the lowest concentrations (5.0 and 10.0 mg L-1) of lead the mineralization was lower, however, the reaction coefficients and the amount of oxygen consumed were equivalent to the control. At the highest concentrations (20.0 and 30.0 mg L-1) the mineralization was increased, with the reduction of reaction coefficients and higher oxygen consumption.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

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