scholarly journals Cypriniform fish in running waters reduce hyporheic oxygen depletion in a eutrophic river

2020 ◽  
Vol 65 (9) ◽  
pp. 1518-1528 ◽  
Author(s):  
Dirk Hübner ◽  
Madlen Gerke ◽  
Roman Fricke ◽  
Jörg Schneider ◽  
Carola Winkelmann
Keyword(s):  
Oxygen Depletion ◽  
Running Waters ◽  
Eutrophic River

scholarly journals Hypoxia and anoxia effects on alcohol dehydrogenase activity and hemoglobin content in Chironomus riparius Meigen, 1804

2016 ◽  
Author(s):  
Valentina Grazioli ◽  
Bruno Rossaro ◽  
Paolo Parenti ◽  
Roberto Giacchini ◽  
Valeria Lencioni
Keyword(s):  
Alcohol Dehydrogenase ◽  
Oxygen Saturation ◽  
Oxygen Depletion ◽  
Chironomus Riparius ◽  
Oxygen Storage ◽  
Metabolic Effects ◽  
Running Waters ◽  
Low Oxygen ◽  
Short Term ◽  
Adh Activity

<p>The metabolic effects of low oxygen content on alcohol-dehydrogenase (ADH) activity and hemoglobin (Hb) concentration were investigated in IV-instar larvae of <em>Chironomus riparius </em>(Diptera: Chironomidae) from an Italian stream. Two series of short-term (48 h) experiments were carried out: exposure to (1) progressive hypoxia (95 to 5% of oxygen saturation) and (2) anoxia (at &lt;5% of oxygen saturation). In (1), Hb amount increased with increasing oxygen depletion up to a critical value of oxygenation (about 70% of oxygen saturation). Below this percentage, the Hb amount declined to values comparable with those present in the control. The respiration rate (R) remained almost constant at oxygen saturation &gt;50% and decreased significantly only after 48 h of treatment (= &lt;5% of oxygen saturation) reaching values &lt;100 mmolO<sub>2</sub> gAFDW<sup>-1</sup> h<sup>-1</sup>. ADH activity showed two phases of growth, within the first 14 h and over 18 h of exposure. Overall, we inferred that i) Hb might function as short-term oxygen storage, enabling animals to delay the on-set of anaerobiosis; and ii) alcoholic fermentation co-occurs for a short time with aerobic respiration, becoming the prevalent metabolic pathway below 5% of oxygen saturation (&lt;1 mg L<sup>-1</sup>). These considerations were supported also by results from anoxia exposure (2). In such condition, larvae were visibly stressed, becoming immobile after few minutes of incubation, and ADH reached higher values than in the hypoxia treatment (2.03±0.15 UADH mg prot<sup>-1</sup>). Overall, this study showed a shift from aerobic to anaerobic activity in <em>C. riparius</em> larvae exposed to poorly oxygenated water with an associated alteration of ADH activity and the Hb amount. Such metabolites might be valid candidate biomarkers for the environmental monitoring of running waters.</p>

Low-temperature annealing of YBa2Cu3O7-x

1992 ◽  
Vol 50 (1) ◽  
pp. 88-89
Author(s):  
R.L. Sabatini ◽  
Yimei Zhu ◽  
Masaki Suenaga ◽  
A.R. Moodenbaugh
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Temperature ◽  
Oxygen Diffusion ◽  
Diffusion Rate ◽  
Oxygen Depletion ◽  
Low Temperature Annealing ◽  
Transmission Electron ◽  
Microstructural Effects ◽  
Oxygen Diffusion Rate

Low temperature annealing (<400°C) of YBa2Cu3O7x in a ozone containing oxygen atmosphere is sometimes carried out to oxygenate oxygen deficient thin films. Also, this technique can be used to fully oxygenate thinned TEM specimens when oxygen depletion in thin regions is suspected. However, the effects on the microstructure nor the extent of oxygenation of specimens has not been documented for specimens exposed to an ozone atmosphere. A particular concern is the fact that the ozone gas is so reactive and the oxygen diffusion rate at these temperatures is so slow that it may damage the specimen by an over-reaction. Thus we report here the results of an investigation on the microstructural effects of exposing a thinned YBa2Cu3O7-x specimen in an ozone atmosphere using transmission electron microscopy and energy loss spectroscopy techniques.

A description of two new species of water mites of the genus Torrenticola Piersig, 1896 (Acariformes: Hydrachnidia: Torrenticolidae) from the Krasnodar Kray, Russia

2013 ◽  
Vol 22 (2) ◽  
pp. 181-188
Author(s):  
P.V. Tuzovskij
Keyword(s):  
New Species ◽  
Mite Species ◽  
Running Waters ◽  
Water Mites ◽  
North Caucasus ◽  
Water Mite ◽  
The North ◽  
Two New Species

Two new water mite species, Torrenticola amplexella and T. krasnodarensis, from running waters of the North Caucasus (Krasnodar Kray) are described with illustrations.

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.

Towards Control of an Estuary

1987 ◽  
Vol 19 (9) ◽  
pp. 155-174
Author(s):  
Henk L. F. Saeijs
Keyword(s):  
Shallow Water ◽  
Storm Surge ◽  
Salt Marshes ◽  
Large Scale ◽  
Western Europe ◽  
Oxygen Depletion ◽  
Negative Effects ◽  
Intertidal Flats ◽  
Environmental Consequences ◽  
Short Time

The Delta Project is in its final stage. In 1974 it was subjected to political reconsideration, but it is scheduled now for completion in 1987. The final touches are being put to the storm-surge barrier and two compartment dams that divide the Oosterschelde into three areas: one tidal, one with reduced tide, and one a freshwater lake. Compartmentalization will result in 13% of channels, 45% of intertidal flats and 59% of salt marshes being lost. There is a net gain of 7% of shallow-water areas. Human interventions with large scale impacts are not new in the Oosterschelde but the large scale and short time in which these interventions are taking place are, as is the creation of a controlled tidal system. This article focusses on the area with reduced tide and compares resent day and expected characteristics. In this reduced tidal part salt marshes will extend by 30–70%; intertidal flats will erode to a lower level and at their edges, and the area of shallow water will increase by 47%. Biomass production on the intertidal flats will decrease, with consequences for crustaceans, fishes and birds. The maximum number of waders counted on one day and the number of ‘bird-days' will decrease drastically, with negative effects for the wader populations of western Europe. The net area with a hard substratum in the reduced tidal part has more than doubled. Channels will become shallower. Detritus import will not change significantly. Stratification and oxygen depletion will be rare and local. The operation of the storm-surge barrier and the closure strategy chosen are very important for the ecosystem. Two optional closure strategies can be followed without any additional environmental consequences. It was essential to determine a clearly defined plan of action for the whole area, and to make land-use choices from the outset. How this was done is briefly described.

The waterscape at high altitudes

2017 ◽  
Author(s):  
Dean Jacobsen ◽  
Olivier Dangles
Keyword(s):  
High Altitude ◽  
Regional Climate ◽  
Water Source ◽  
Aquatic Systems ◽  
Running Waters ◽  
High Altitudes ◽  
Different Types ◽  
Geological Origin ◽  
Broad Variety ◽  
The Tropics

Chapter 2 presents the amazing variety of running waters, lakes, ponds, and wetlands found at high altitudes. These waterbodies are not equally distributed among the world’s high altitude places, but tend to be concentrated in certain areas, primarily determined by regional climate and topography. Thus, a large proportion of the world’s truly high altitude aquatic systems are found at lower latitudes, mostly in the tropics. The chapter presents general patterns in the geographical distribution of high altitude waters, and gives examples of some of the most extreme systems. High altitude aquatic systems and habitats cover a broad variety in dynamics and physical appearance. These differences may be related to, for example, water source (glacier-fed, rain-fed, or groundwater-fed streams), geological origin (e.g. glacial, volcanic, or tectonic lakes), or catchment slope and altitude (different types of peatland wetlands). This is exemplified and richly illustrated through numerous photos.

scholarly journals Use of Amperometric and Potentiometric Probes in Scanning Electrochemical Microscopy for the Spatially-Resolved Monitoring of Severe Localized Corrosion Sites on Aluminum Alloy 2098-T351

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1132 ◽  
Author(s):  
Rejane M. P. da Silva ◽  
Javier Izquierdo ◽  
Mariana X. Milagre ◽  
Abenchara M. Betancor-Abreu ◽  
Isolda Costa ◽  
...  
Keyword(s):  
Scanning Electrochemical Microscopy ◽  
Oxygen Depletion ◽  
Localized Corrosion ◽  
Alloy Surface ◽  
Al Alloy ◽  
Spatially Resolved ◽  
Lower Oxygen ◽  
Local Ph ◽  
Electrochemical Microscopy

Amperometric and potentiometric probes were employed for the detection and characterization of reactive sites on the 2098-T351 Al-alloy (AA2098-T351) using scanning electrochemical microscopy (SECM). Firstly, the probe of concept was performed on a model Mg-Al galvanic pair system using SECM in the amperometric and potentiometric operation modes, in order to address the responsiveness of the probes for the characterization of this galvanic pair system. Next, these sensing probes were employed to characterize the 2098-T351 alloy surface immersed in a saline aqueous solution at ambient temperature. The distribution of reactive sites and the local pH changes associated with severe localized corrosion (SLC) on the alloy surface were imaged and subsequently studied. Higher hydrogen evolution, lower oxygen depletion and acidification occurred at the SLC sites developed on the 2098-T351 Al-alloy.

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

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