Bubble Disease Research Articles

Mycoselectivity of Mushroom Compost and Surfaces, Disinfected with Gas Chlorine Dioxide

In order to limit losses in mushroom cultivation, various methods and measures are used to prevent the development of pathogens. However, frequently occurs the effective disinfection does not result directly a positive response in the form of increased yielding or at least reduction of the problems of infections with green mould or bubble diseases. The studies presented in this paper show that even with a relatively high level of inoculation of phase II compost containing Trichoderma aggressivum (105/cm3), significantly exceeding the potential intensity of natural infections, Agaricus bisporus remained dominant in the environment. On the other hand, an excessive disinfection disturbed this balance in favor of the more disinfectant-resistant pathogen. High efficacy of the innovative gas ClO2 disinfection, at the applied balance concentration 1000 ppm (m/m) was determined on the surfaces of the cultivation hall. However, the study demonstrates that effective disinfection of compost may give the effects of weakening of mushroom spawn mycelium and domination of its environment by the competing pathogens.

Incorporating Fish Tolerance to Supersaturated Total Dissolved Gas for Generating Flood Pulse Discharge Patterns Based on a Simulation‐Optimization Approach

AbstractSupersaturated total dissolved gas (STDG) caused by the flood discharge can result in bubble disease and even fish death, posing potential risks to aquatic ecosystems. In order to reduce the impacts of STDG on such ecosystem, a dynamic multi‐objective STDG management model (DMO‐STDGM) with the flood pulse discharge pattern is developed based on the prototype observation and laboratory test analysis, which consists of STDG prediction, fish safety assessment, multi‐objective optimization and 2‐D STDG transport diffusion simulation modules. The proposed model can support generation of flood pulse discharge patterns to reduce the level of STDG and minimize the maximum residence time of STDG water. The developed model is applied to optimize the discharge pattern of Xiluodu project to reduce the effects of STDG on fish. Simulation results of the worst scenario with the flood pulse discharge pattern show that the maximum residence time of STDG for T120%, T125%, T130%, and T140% are 12, 9, 4, 3 and 1 h, which are less than the corresponding LT50s (Mean Lethal Time). It means that the physiological function of fish can recover from the affect of STDG, thus fish can survive in the worst scenario. The established model can also be employed for increasing power generation. Simulation results indicate that the flood pulse discharge pattern with equal weight of ecology and power generation can ensure full load operation of hydropower station with 12,600 MW. The established model is widely applicable and can provide an important theoretical and technical support for water quality and ecosystem management under multiple complexities.

The impact of different gas mixtures on inflammatory responses in advanced recreational divers.

Decompression sickness (DCS) is considered a 'bubble disease'. Intravascular bubbles activate inflammatory responses associated with endothelial dysfunction. Breathing gas has been proposed as a potential risk factor but this is inadequately studied. Different gases are used in scuba diving. Helium-containing 'trimix' could theoretically mitigate inflammation and therefore reduce DCS risk. This study determined the effect of air and trimix on the inflammatory response following dives to 50 metres of sea water, and evaluated the differences between them in advanced recreational divers. Thirty-three divers were enrolled in this observational study and were divided in two groups: 17 subjects were included in the air group, and 16 different subjects were included in the trimix (21% oxygen, 35% helium, 44% nitrogen) group. Each subject conducted a single dive, and both groups used a similar diving profile of identical duration. A venous blood sample was taken 30 min before diving and 2 h after surfacing to evaluate changes in interleukins (IL) IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, tumour necrosis factor α (TNFα), vascular endothelial growth factor (VEGF), Interferon γ (IFN-γ), monocyte chemoattractant protein 1 (MCP-1) and epithelial growth factor (EGF) after diving. No differences were observed between groups in demographic data or diving experience. Following the dive, IL-6 values showed a slight increase, while IL-8 and EGF decreased in both groups, without significant variation between the groups. In physically fit divers, trimix and air gas mixture during deep diving did not cause relevant changes in the inflammatory markers tested.

Experimental Study on the Effects of Vegetation on the Dissipation of Supersaturated Total Dissolved Gas in Flowing Water.

High dam discharge can lead to total dissolved gas (TDG) supersaturation in the downstream river, and fish in the TDG-supersaturated flow can suffer from bubble disease and even die. Consequently, it is of great value to study the transport and dissipation characteristics of supersaturated dissolved gas for the protection of river fish. Floodplains may form downstream of high dams due to flood discharge, and the plants on these floodplains can affect both the hydraulic characteristics and TDG transport of the flowing water. In this study, the velocity distribution and the retention response time under different flow conditions and vegetation arrangements were studied in a series of experiments. The retention time was significantly extended by the presence of vegetation, and an empirical formula for calculating the retention time was proposed. In addition, the responses of the dissipation process of supersaturated TDG to hydraulic factors, retention time, and vegetation area coefficient were analyzed. The dissipation of supersaturated TDG significantly increased with increases in the vegetation area coefficient in the water. To quantitatively describe the TDG dissipation process in TDG-supersaturated flow under the effect of vegetation, the TDG dissipation coefficient was fitted and analyzed. The basic form of the formula for the dissipation coefficient involving various influence factors was determined by dimensional analysis. An equation for calculating the TDG dissipation coefficient of flowing water with vegetation was proposed by multivariate nonlinear fitting and was proven to have great prediction accuracy. The calculated method developed in this paper can be used to predict TDG dissipation in flowing water with vegetation and is of great significance for enriching TDG prediction systems.

A Simple Apparatus for Maintaining Gas‐Supersaturated Seawater in the Laboratory for Experimental Purposes

AbstractGas bubble disease caused by supersaturated conditions is generally well understood for commercially important freshwater species, such as salmon and trout, but very little is known about impacts to marine finfish culture. We developed a relatively simple, low‐cost apparatus to expose juvenile white seabass Atractoscion nobilis and striped bass Morone saxatilis to multiple gas saturation levels simultaneously. We found that the system was capable of operating under different temperatures and accommodating a range of juvenile fish sizes. Gas saturation treatments were maintained by mixing a supersaturated seawater source with a saturated one. The supersaturated seawater source was created by reducing pressure of an air‐ or oxygen‐equilibrated water source maintained at a pressure of 623.2 mm Hg. The saturated seawater source was achieved by degassing seawater using a packed column. By mixing these two water sources manually by use of needle valves, differential gas pressures (ΔP) ranging from 0.0 to 167.2 mm Hg were maintained. The control treatment level ranged from −35.7 to 0 mm Hg and was maintained using a vacuum degasser. Oxygen‐nitrogen (O2:N2) ratios ranged from 0.83 to 1.41. Temperature within the experiment was computer controlled. The supersaturation apparatus operated very effectively and delivered treatment levels that were stable and significantly different from one another throughout all trials.

BOOK REVIEWS

Books Reviewed in this Article:RESPIRATION OF AMPHIBIOUS VERTEBRATES Edited by Prof. G. M. Hughes.GAS BUBBLE DISEASE by D. H. Fickeisen and M. J. Schneider