scholarly journals Influence of Channel Regulating Structures on the Transportation and Dissipation of Supersaturated Total Dissolved Gas

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yun Qing ◽  
Qian Ma ◽  
Ran Li ◽  
Xia Shen ◽  
XuJin Zhang ◽  
...  
Keyword(s):  
Impact Evaluation ◽  
Scientific Basis ◽  
Gas Bubble ◽  
Two Dimensional ◽  
Slow Process ◽  
Dissolved Gas ◽  
Inland Waterways ◽  
Total Dissolved Gas ◽  
Dissipation Model ◽  
Gas Bubble Disease

Bubble dissolution during the flood discharge creates high total dissolved gas (TDG) concentration zones downstream of the dams. The dissipation of supersaturated TDG is a very slow process. Thus, the elevated TDG may remain through the water body for hundreds of kilometers downstream and lead to gas bubble disease (GBD) and even mortality in fish. To improve the navigation conditions of waterways, dikes (i.e., a solid structure) of varied sizes and shapes are commonly constructed. However, this would affect the dissipation and transportation of the supersaturated TDG. It would significantly change the turbulence intensity and hydropressure of the flow, which dominates the dissipation of TDG. Therefore, TDG distribution in the waterway differs from that in the natural river. In this study, a numerical simulation of the TDG at the Yangtze River’s upper reaches (one of the inland waterways in China) was conducted with the establishment of a two-dimensional TDG dissipation model. The effect of the dikes’ size and shape was analyzed to assess the influence of the regulation structures on the dissipation and transportation of the supersaturated TDG. Meanwhile, simulation in the study area with the natural topography was also set as blank control. Based on that, impact evaluation of TDG supersaturation on fish under different simulation scenarios was made. This study can provide a scientific basis for reducing the adverse effect of supersaturated TDG in fish and the construction of ecological waterway therefore.

Understanding gas bubble trauma in an era of hydropower expansion: how do fish compensate at depth?

2020 ◽  
Vol 77 (3) ◽  
pp. 556-563 ◽  
Author(s):  
Naomi K. Pleizier ◽  
Charlotte Nelson ◽  
Steven J. Cooke ◽  
Colin J. Brauner
Keyword(s):  
Bubble Growth ◽  
Gas Bubble ◽  
Hydroelectric Dams ◽  
Dissolved Gas ◽  
Empirical Relationships ◽  
Lethal Effects ◽  
Exposed Fish ◽  
Total Dissolved Gas ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Relationship

Hydrostatic pressure is known to protect fish from damage by total dissolved gas (TDG) supersaturation, but empirical relationships are lacking. In this study we demonstrate the relationship between depth, TDG, and gas bubble trauma (GBT). Hydroelectric dams generate TDG supersaturation that causes bubble growth in the tissues of aquatic animals, resulting in sublethal and lethal effects. We exposed fish to 100%, 115%, 120%, and 130% TDG at 16 and 63 cm of depth and recorded time to 50% loss of equilibrium and sublethal symptoms. Our linear model of the log-transformed time to 50% LOE (R2 = 0.94) was improved by including depth. Based on our model, a depth of 47 cm compensated for the effects of 4.1% (±1.3% SE) TDG supersaturation. Our experiment reveals that once the surface threshold for GBT from TDG supersaturation is known, depth protects rainbow trout (Oncorhynchus mykiss) from GBT by 9.7% TDG supersaturation per metre depth. Our results can be used to estimate the impacts of TDG on fish downstream of dams and to develop improved guidelines for TDG.

Effect of Carbon Monoxide Exposure on Gas Bubble Disease in Rainbow Trout (Salmo gairdneri)

1989 ◽  
Vol 46 (1) ◽  
pp. 74-80 ◽  
Author(s):  
J. P. Machado ◽  
T. G. Bell ◽  
A. L. Trapp ◽  
D. L. Garling Jr. ◽  
N. R. Kevern
Keyword(s):  
Carbon Monoxide ◽  
Rainbow Trout ◽  
Survival Time ◽  
Prolonged Survival ◽  
Salmo Gairdneri ◽  
Gas Bubble ◽  
Dissolved Gas ◽  
Gas Bubble Disease ◽  
Gill Filaments ◽  
Afferent Arterioles

Cumulative mortalities of 100, 50, 20, and 0% due to gas bubble disease (GBD) occurred on exposure of rainbow trout (Salmo gairdneri) for 180 min to supersaturated water at 136, 130, 124, and 116% total dissolved gas saturation (TDGS), respectively. At 130% TDGS, a prior exposure to carbon monoxide (CO), which converted 80% of the hemoglobin to carboxyhemoglobin (COHb), significantly prolonged survival time, but cumulative mortality was insignificantly reduced in the same group. Histologically, all supersaturation mortalities had branchial lesions for GBD (characterized by gas displacement of blood from the afferent arterioles of the gill filaments), while 70% had gas emboli in the retinal choroid gland. At a TDGS of 100%, these histological lesions were not observed and the CO 80% COHb conversion did not induce mortality within 120 min. Breathing movements of both control and CO-exposed fish slowed greatly when a TDGS of 130% was imposed; however, the COHb conversion initiated tachypnea and the CO-treated fish maintained a relatively higher respiratory rate when exposed to supersaturation conditions for a period which was proportional to their prolonged survival time. We concluded that the initial formation of gas emboli preceding fatal GBD was delayed as a result of a CO-inhibited function of hemoglobin.

scholarly journals Lethal Effect of Total Dissolved Gas-Supersaturated Water with Suspended Sediment on River Sturgeon (Acipenser dabryanus)

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Xiaoqing Liu ◽  
Na Li ◽  
Cuixia Feng ◽  
Chenghua Fu ◽  
Quan Gong ◽  
...  
Keyword(s):  
Suspended Sediment ◽  
Lethal Effect ◽  
Dissolved Gas ◽  
Total Dissolved Gas ◽  
Gas Bubble Disease ◽  
Lethal Time ◽  
Test Fish ◽  
Fish Survival ◽  
Study Laboratory ◽  
Abnormal Behaviors

Abstract High total dissolved gas (TDG) levels and excessive suspended sediment (SS) concentrations pose serious threats to fish survival during flood season. However, little information is available on the effects of TDG supersaturation with varying SS concentrations on fish. In this study, laboratory experiments were performed to investigate the effects of TDG supersaturation with varying SS concentrations on five-month-old river sturgeons (Acipenser dabryanus). The test fish were exposed to combinations of SS concentrations (0, 200, 600 and 1,000 mg/L) and TDG levels (125, 130, 135 and 140%), and their mortality and median lethal time (LT50) were quantified. The fish showed abnormal behaviors (e.g., quick breathing, fast swimming and an agitated escape response) and symptoms of gas bubble disease (GBD). SS increased the mortality of river sturgeon exposed to TDG supersaturation. Furthermore, the LT50 values at 125% TDG were 4.47, 3.11, 3.07 and 2.68 h for the different SS concentrations (0, 200, 600 and 1,000 mg/L, respectively), representing a significant decrease in LT50 with increasing SS. However, at higher TDG levels (130–140%), there was no significant increase in LT50 with increasing SS. Therefore, river sturgeon showed weak tolerance of TDG-supersaturated water with SS.

scholarly journals Numerical Model of Supersaturated Total Dissolved Gas Dissipation in a Channel with Vegetation

Water ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1769 ◽  
Author(s):  
Youquan Yuan ◽  
Yinghan Huang ◽  
Jingjie Feng ◽  
Ran Li ◽  
Ruidong An ◽  
...  
Keyword(s):  
Flood Control ◽  
Three Dimensional ◽  
Vegetation Density ◽  
Dissolved Gas ◽  
Two Phase ◽  
Total Dissolved Gas ◽  
Dissipation Coefficient ◽  
Dissipation Model ◽  
Average Water ◽  
The Impact

The recent construction and operation of high dams have greatly changed the natural flood process. To meet the ecological demands and flood control requirements of rivers, dams discharge flow through the flood discharge facility, always accompanied by total dissolved gas (TDG) supersaturation in the water, which is harmful to fish. The purpose of this paper is to explore the dissipation characteristics and prediction methods of supersaturated TDG in water flowing through a floodplain covered with vegetation. A three-dimensional two-phase supersaturated TDG transportation and dissipation model considering the effects of vegetation was established. Using existing mechanism experimental results, the inner dissipation coefficient kin of TDG in vegetation-affected flows was studied, and the quantitative relationships between the inner dissipation coefficient kin and the average flow velocity, average water depth, average water radius, Reynolds number, and vegetation density were characterized. Based on the simulation results, the distribution characteristics of the supersaturated TDG in water around vegetation and in the vertical, lateral, and longitudinal directions of the flume under different flow and vegetation densities were analyzed. A supersaturated TDG transportation and dissipation model for vegetation-affected flow is proposed and can be used to predict the impact of TDG in a floodplain.

Occurrence of Gas-Bubble Disease in Three Species of Bivalve Molluscs

1972 ◽  
Vol 29 (5) ◽  
pp. 588-589 ◽  
Author(s):  
Robert Malouf ◽  
Richard Keck ◽  
Don Maurer ◽  
Charles Epifanio
Keyword(s):  
Sea Water ◽  
Gas Bubble ◽  
Atmospheric Gases ◽  
Dissolved Gas ◽  
Bivalve Molluscs ◽  
Gas Concentration ◽  
Head Tank ◽  
Gas Bubble Disease ◽  
Gill Filaments ◽  
Hard Clams

Gas-bubble disease was observed in adult oysters and hard clams held in heated running sea water during the winter. Heating the cold sea water in closed heat exchangers caused it to become supersaturated with atmospheric gases. Exposure of the animals to this water caused the formation of gas-filled conchiolin blisters on the valves of the oysters. Bubbles of gas were observed in the gill filaments of the oysters and clams and in the mantle tissue of the oysters. Any method, such as the use of baffles or an aerated head tank, that reduces the dissolved gas concentration in the water will help prevent the disease.

scholarly journals The effect of total dissolved gas supersaturation on gas bubble trauma in juvenile rainbow trout (Oncorhynchus mykiss), juvenile kokanee (Oncorhynchus nerka) and two age classes of white sturgeon (Acipenser transmontanus).

2021 ◽  
Author(s):  
Anthony Kovac ◽  
Naomi K. Pleizier ◽  
Colin J Brauner
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Oncorhynchus Nerka ◽  
White Sturgeon ◽  
Acipenser Transmontanus ◽  
Gas Bubble ◽  
Dissolved Gas ◽  
Total Dissolved Gas ◽  
Juvenile Rainbow Trout ◽  
Total Dissolved Gas Supersaturation

Hydroelectric dams are an important source of electricity globally, but they can also cause total dissolved gas (TDG) supersaturation in rivers. Total dissolved gas supersaturation can harm fish through a condition called gas bubble trauma (GBT). Gas bubble trauma has been studied primarily in salmonids, such as rainbow trout and steelhead salmon (Oncorhynchus mykiss), but seldomly in non-salmonids like white sturgeon (Acipenser transmontanus). We assessed the vulnerability of juvenile rainbow trout (<1 year old), juvenile kokanee (Oncorhynchus nerka) (<1 year old), and two ages of white sturgeon (<1 year old and 3+ year old) to GBT. Bubble formation and the time to 50% loss of equilibrium (LOE) was quantified during exposure to nominal levels of 100, 115, 120 and 130% TDG. We predicted that all three species would show similar times to 50% LOE at a given TDG level. However, time to LOE was longer, the proportion of fish with external symptoms of GBT was lower and the proportion of fish with bubbles in the gills was higher or lower (dependant on age) in white sturgeon relative to rainbow trout and kokanee at a given TDG. The physiological basis for the difference is not known. However, it is important to consider species specific differences in TDG sensitivity in the conservation of vulnerable species

Sign in / Sign up

Export Citation Format

Share Document