scholarly journals Wind-driven stratification patterns and dissolved oxygen depletion in the area off the Changjiang (Yangtze) Estuary

2019 ◽  
Author(s):  
Anonymous
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Depletion ◽  
Yangtze Estuary

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.

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.

scholarly journals Oxygen depletion in subarctic peatland thaw lakes

2017 ◽  
Vol 3 (2) ◽  
pp. 406-428 ◽  
Author(s):  
Bethany N. Deshpande ◽  
Frédéric Maps ◽  
Alex Matveev ◽  
Warwick F. Vincent
Keyword(s):  
Dissolved Oxygen ◽  
Ice Cover ◽  
Oxygen Depletion ◽  
Freshwater Ecosystems ◽  
In Situ Sensors ◽  
Modelling Studies ◽  
Bottom Waters ◽  
Bacterial Decomposition ◽  
Permafrost Thawing ◽  
Thaw Lakes

Permafrost thawing and erosion results in the enrichment of northern lakes by soil organic matter. These allochthonous inputs favour bacterial decomposition and may cause the draw-down of dissolved oxygen to anoxic conditions that promote methanogenesis. Our objective in the present study was to determine the seasonal variations in dissolved oxygen in a set of permafrost peatland lakes in subarctic Quebec, Canada, and to relate these changes to metabolic rates, ice cover, and mixing. The lakes had high dissolved organic carbon concentrations, and their surface waters in summer had greenhouse gas concentrations that were up to one (CO2) to three (CH4) orders of magnitude above air-equilibrium values, indicating their strongly heterotrophic character. Consistent with these observations, the peatland lakes had elevated rates of bacterial production and oxygen consumption. Continuous measurements of oxygen by in situ sensors and of ice cover by automated field cameras showed that the lakes became fully anoxic shortly after freeze-up. The waters were partially re-oxygenated by mixing events in spring and fall, but in one lake, the bottom waters remained anoxic throughout the year. These observations provide a foundation for subsequent biogeochemical and modelling studies of peatland thaw lakes as an abundant class of Arctic freshwater ecosystems.

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 Environmental and climatic factors affecting winter hypoxia in a freshwater lake: evidence for a hypoxia refuge and for re-oxygenation prior to spring ice loss

Hydrobiologia ◽  
2020 ◽  
Vol 847 (19) ◽  
pp. 3983-3997
Author(s):  
Michael N. Davis ◽  
Thomas E. McMahon ◽  
Kyle A. Cutting ◽  
Matthew E. Jaeger
Keyword(s):  
Dissolved Oxygen ◽  
Spatial Variability ◽  
Climatic Factors ◽  
Oxygen Depletion ◽  
Late Winter ◽  
Factors Affecting ◽  
Arctic Grayling ◽  
Air Temperatures ◽  
Depletion Rate ◽  
Rock Lake

Abstract Low dissolved oxygen, or hypoxia, is a common phenomenon in ice-covered lakes in winter. We measured dissolved oxygen (DO) before, during, and after ice-over to characterize the timing, severity, and spatial variability of winter hypoxia in Upper Red Rock Lake, Montana, home to one of the last remaining lacustrine populations of endemic Montana Arctic Grayling (Thymallus arcticus). Unlike most previous investigations of winterkill-prone lakes, we observed considerable horizontal spatial variability in DO, a non-linear winter oxygen depletion rate, and lake-wide re-oxygenation 2–4 weeks prior to spring ice loss. Parts of the upper 1 m of the lake and near stream mouths remained well-oxygenated even during late winter. DO levels were strongly associated with maximum daily air temperature. Our analysis of a 28-year weather record revealed large interannual variability in risk of winter hypoxia, with a slight declining trend in winter severity (number of days with maximum air temperatures ≤ 0°C) in Upper Red Rock Lake. The approach we used in our study provides a useful framework for quantifying and mapping the seasonal dynamics of the extent and severity of winter hypoxia, and for identifying critical winter habitats.

Oxygen Depletion and Winterkill Risk in Small Prairie Lakes Under Extended Ice Cover

1979 ◽  
Vol 36 (8) ◽  
pp. 980-986 ◽  
Author(s):  
Jan Barica ◽  
John A. Mathias
Keyword(s):  
Dissolved Oxygen ◽  
Average Rate ◽  
Oxygen Depletion ◽  
Oxygen Storage ◽  
Lake Depth ◽  
Fish Kill ◽  
Initial Oxygen ◽  
Storage Rate ◽  
Prairie Lakes ◽  
The Mean

Mean rates of dissolved oxygen depletion in 10 shallow eutrophic prairie lakes (area 2.3–27.3 ha, mean depth 1.6–4.2 m), ranged from 0.22 to 0.34 g/m2∙d−1 for nonstratified lakes and 0.32–0.42 g/m2∙d−1 for stratified ones. An average rate for all lakes was 0.29 ± 0.06 g/m2∙d−1. The rates correlated with the lake depth. A method for estimating the winterkill risk on the basis of initial oxygen storage, rate of dissolved oxygen depletion and/or the mean or maximum lake depth is proposed. Key words: prairie lakes, oxygen depletion rates, winter fish kill, eutrophication, metabolism, oxygen storage

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.

Causal Stochastic Simulation of Dissolved Oxygen Depletion in Rivers Receiving Combined Sewer Overflows

1994 ◽  
Vol 29 (1-2) ◽  
pp. 191-198 ◽  
Author(s):  
K. Schaarup-Jensen ◽  
T. Hvitved-Jacobsen
Keyword(s):  
Dissolved Oxygen ◽  
Extreme Event ◽  
Oxygen Depletion ◽  
Model Parameters ◽  
Combined Sewer Overflows ◽  
Quality Model ◽  
Combined Sewer ◽  
Model Mouse ◽  
Sewer Overflows ◽  
Runoff Model

A method for stochastic analysis of the effect of combined sewer overflows on the dissolved oxygen concentration in receiving rivers is developed. The method is based on repeated operation of the water quality model MOUSE-DOSMO. Each operation of this model covers a series of overflow events calculated by the MOUSE-SAMBA runoff model based on a historical rainfall record. For each event selected input data and model parameters in both models are drawn from fundamental statistical distributions by a simple Monte Carlo method. These data and parameters vary from event to event in each series. Each operation of the MOUSE-DOSMO model results in an extreme event statistics on dissolved oxygen minimum values -while repeated operation of the model yields extreme event percentiles by means of which a probability-based assessment of the model result may be performed.

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