scholarly journals Prolonged exposure to low oxygen improves hypoxia tolerance in a freshwater fish

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Kayla L Gilmore ◽  
Zoe A Doubleday ◽  
Bronwyn M Gillanders
Keyword(s):  
Freshwater Fish ◽  
Prolonged Exposure ◽  
Hypoxia Tolerance ◽  
Low Oxygen ◽  
Oxygen Conditions

Lay summary It is poorly understood whether fish can acclimate to prolonged low-oxygen conditions (or hypoxia). Our study shows that prior long-term exposure to low-oxygen conditions improves tolerance to low-oxygen in a freshwater fish. The results of our study aid our understanding of long-term responses of freshwater fish to low-oxygen to hypoxic events.

scholarly journals Behavioural responses of caddisfly larvae (Hydropsyche angustipennis) to hypoxia

2007 ◽  
Vol 76 (4) ◽  
pp. 255-260 ◽  
Author(s):  
H.G. van der Geest
Keyword(s):  
Habitat Suitability ◽  
Model Organism ◽  
Ventilation Rate ◽  
Hypoxia Tolerance ◽  
Survival Strategies ◽  
Low Oxygen ◽  
Caddisfly Larvae ◽  
Oxygen Conditions ◽  
Behavioural Test ◽  
Impedance Conversion

The availability of aquatic oxygen can limit habitat suitability for benthic insects, and differences in hypoxia tolerance can therefore play a role in explaining distributions in the field. This study describes a behavioural test in which the trade off between different survival strategies after exposure to different oxygen concentrations is analyzed, using the caddisfly Hydropsyche angustipennis as a model organism. The impedance conversion technique was used to quantify patterns of behaviour for individual caddisflies at three levels of dissolved oxygen (100%, 50%, and 30% saturation) under controlled laboratory conditions. Exposure to hypoxia resulted in behavioural changes: under low-oxygen conditions, larvae increased their ventilation rate, which may increase oxygen uptake. However, they also increased the time spent on other activities, which may reflect avoidance behaviour.

scholarly journals The effects of intermittent exposure to low pH and oxygen conditions on survival and growth of juvenile red abalone

2013 ◽  
Vol 10 (2) ◽  
pp. 3559-3576 ◽  
Author(s):  
T. W. Kim ◽  
J. P. Barry ◽  
F. Micheli
Keyword(s):  
Growth Rate ◽  
Individual Variation ◽  
Prolonged Exposure ◽  
Low Ph ◽  
Low Oxygen ◽  
Haliotis Rufescens ◽  
Oxygen Levels ◽  
Red Abalone ◽  
Intermittent Exposure ◽  
Oxygen Conditions

Abstract. Exposure of nearshore animals to hypoxic, low pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low pH and/or low oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5–10 mm). Mortality rates of juvenile abalone exposed to low pH (7.5, total scale) and low O2 (40% saturation, 5 mg L−1) conditions for periods of 3 to 6 h every 3–5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L−1; pH 8.0). However, when exposure was extended to 24 h repeated twice over a 15 day period, juveniles experienced higher mortality in the low oxygen treatments compared to control conditions, regardless of pH levels (pH 7.5 vs. 8.0). Growth rates were reduced significantly when juveniles were exposed to low pH or low oxygen treatments and the growth was lowest when low pH exposure was combined with low O2. Furthermore, individual variation of growth rate increased when they were exposed to low pH and low O2 conditions. These results indicate that prolonged exposure to low oxygen levels is detrimental for the survival of red abalone, whereas both pH and oxygen is a crucial factor for their growth. However, given the higher individual variation in growth rate, they may have an ability to adapt to extended exposure to upwelling conditions.

Is long-term hypoxia met by the Pasteur effect in roots of wheat seedlings?

1994 ◽  
Vol 102 ◽  
pp. 407-412 ◽  
Author(s):  
G. Albrecht ◽  
E.-M. Wiedenroth
Keyword(s):  
Hypoxia Tolerance ◽  
Soluble Carbohydrates ◽  
Low Oxygen ◽  
Wheat Roots ◽  
Wheat Seedlings ◽  
Pasteur Effect ◽  
Metabolic Arrest ◽  
Oxygen Shortage ◽  
Anaerobic Environment

SynopsisIt has been argued, whether or not the Pasteur effect occurs in plant tissues as a response to long-term hypoxia. To study this question roots of wheat seedlings (Triticum aestivum L. cv. Alcedo) were analysed following acclimation to oxygen shortage by a prior 6-d-cultivation in a nitrogen-flushed nutrient solution. A Pasteur Quotient of approximately one suggested the absence of a significant Pasteur effect. This conclusion was supported by finding an accumulation of soluble carbohydrates.A progressive adaptation of hypoxically pretreated wheat roots was indicated by measurements under low oxygen tension of 2 kPa, when half of the produced carbon dioxide was generated by fermentation (Gas exchange Quotient, GQ≈2.1) with no apparent increase in the glycolytic substrate flux. The remaining oxygen uptake was even higher in hypoxically grown roots than in the aerobically grown control specimens. When whole seedlings were placed in oxygen-free conditions for 2 h, roots of seedlings pretreated hypoxically suffered a 50% loss in the concentration of ATP, while 90% of the ATP was lost in roots transferred from an aerated solution directly into an anaerobic environment. This was interpreted as an improvement in hypoxia tolerance by minimising the fermentation rate (low PQ) but in particular the ATP requirements by metabolic arrest strategies.

scholarly journals Identification of chemical form of stable carbon released from type 304L and 316L stainless-steel powders in alkaline and acidic solutions under low-oxygen conditions

Radiocarbon ◽  
2018 ◽  
Vol 60 (6) ◽  
pp. 1691-1710
Author(s):  
Ryo Nakabayashi ◽  
Tomonari Fujita
Keyword(s):  
Stainless Steel ◽  
Carboxylic Acids ◽  
Safety Assessment ◽  
Silicon Oxide ◽  
Chemical Form ◽  
Low Oxygen ◽  
Colloidal Carbon ◽  
Oxygen Conditions ◽  
Naoh Solution

ABSTRACTThe chemical form of14C released from irradiated stainless steel is a key parameter in the safety assessment of the subsurface disposal system in Japan. In this study, to identify the chemical form of the released carbon, unirradiated stainless-steel powders, which were found to be water-atomized powders with a silicon oxide film, were immersed in NaOH and HCl solutions under low-oxygen conditions for approximately 25 days. The results showed that the main chemical forms of the carbon were colloidal carbon in the NaOH solution and colloidal carbon and formic and acetic acids in the HCl solution. Almost no hydrocarbons were detected in both solution systems. Concerning the source of the colloidal carbon and carboxylic acids, the hypothesis that carbon in the oxide layer is released is considered to be reasonable. The very small amounts of hydrocarbons generated prevented us from discussing the source of the hydrocarbons. To validate the hypothesis and obtain further information on the hydrocarbons, additional experiments are necessary. In particular, for long-term safety assessment, it is important to determine whether the colloidal carbon, carboxylic acids and hydrocarbons are continuously released during the corrosion process. Therefore, information on the temporal evolution of the carbon should be obtained.

scholarly journals Long-term spatiotemporal variations and expansion of low-oxygen conditions in the Pearl River estuary: A study synthesizing observations during 1976–2017

2021 ◽  
Author(s):  
Jiatang Hu ◽  
Zhongren Zhang ◽  
Bin Wang ◽  
Jia Huang
Keyword(s):  
Phytoplankton Biomass ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Low Oxygen ◽  
The Pearl River Estuary ◽  
Oxygen Conditions ◽  
Bottom Waters ◽  
The Pearl River

Abstract. The Pearl River estuary (PRE) frequently experiences low-oxygen conditions in summer, with large extents of low-oxygen events and a long-term deoxygenation trend being reported recently. In this study, we provide a synthesis of the spatiotemporal patterns and incidence of different low-oxygen levels in the PRE based on the in-situ observations collected from 1976 to 2017, and aim to elucidate the underlying mechanisms of low-oxygen conditions and their changes over the past 4 decades. The long-term observations show that the oxygen content in the PRE had significant temporal variability and spatial heterogeneity. Low-oxygen conditions occurred mostly in the bottom waters of 5–30 meters during summer and early autumn, with locations and severity varying substantially among years. Coastal waters from the southwest of Lantau Island to the northeast of Wanshan Islands were identified as the hotspot area prone to subsurface low-oxygen conditions due to the combined effects of comparatively deep topography, proper residence time and stability of the water column, and enhanced oxygen depletion related to high phytoplankton biomass. In addition, the low-oxygen waters, either directly imported from the upstream reaches or generated locally and further transported with the estuarine circulation, also had considerable impacts on the oxygen levels in the estuary. As for early autumn, marked low-oxygen conditions were present both in the surface and bottom waters. A large area affected by low oxygen (~ 4,450 km2) was found in September 2006, where the low-oxygen conditions were comparable to the most severe ones observed in summer and formed by distinct mechanisms. Our analysis also reveals an apparent expansion of the summertime low-oxygen conditions at the bottom of the PRE since the years around 2000, coincident with the major environment changes in the Pearl River region. Overall, the PRE seems to be undergoing a transition from a system characterized by episodic, small-scale hypoxic events to a system with seasonal, estuary-wide hypoxic conditions. Although exacerbated eutrophication associated with anthropogenic nutrient inputs was generally considered the primary cause for the deterioration of low-oxygen conditions in the PRE, the sharp decline in sediment load may play an important role as well via increasing water transparency and thereby supporting higher and broader phytoplankton biomass in the estuary.

Content of major phenolic compounds in apples: Benefits of ultra-low oxygen conditions in long-term storage

2020 ◽  
Vol 92 ◽  
pp. 103587
Author(s):  
Aneta Bílková ◽  
Kristýna Baďurová ◽  
Pavlína Svobodová ◽  
Radek Vávra ◽  
Pavel Jakubec ◽  
...  
Keyword(s):  
Phenolic Compounds ◽  
Low Oxygen ◽  
Long Term Storage ◽  
Oxygen Conditions ◽  
Term Storage

Comparative gill characteristics of Munida quadrispina (Decapoda, Galatheidae) from different habitat oxygen conditions

1988 ◽  
Vol 66 (10) ◽  
pp. 2320-2323 ◽  
Author(s):  
Brenda J. Burd
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Oxygen Depletion ◽  
B Value ◽  
Decapod Crustaceans ◽  
Low Oxygen ◽  
Organic Body ◽  
Oxygen Conditions ◽  
Consumption Rates

The allometric (bilogarithmic) relationship between dry gill weight and organic body weight was compared for benthic galatheid crabs (Munida quadrispina Benedict, 1902) from a low-oxygen fjord and from a normal oxygen population. In the M. quadrispina from the low-oxygen fjord, the slope (b) of the allometric function of gill weight versus body weight was 1.00. This b value was significantly higher (ANCOVA, p < 0.01) than the corresponding slope for the same function in M. quadrispina from normoxic areas (b = 0.63). However, only the largest crabs from the low-oxygen fjord were living consistently in low-oxygen (<0.15 mL/L) conditions; they also had significantly greater (twice as much) relative gill weight than their normoxic counterparts. This observation agrees with findings from previous studies that only the largest M. quadrispina are able to tolerate severe oxygen depletion. Small M. quadrispina from both the low-oxygen fjord and the normoxic area were always found in oxygen concentrations >2.0 mL/L. There were no significant differences between the relative gill sizes of the small crabs from different areas. It was concluded that gill development in M. quadrispina is affected by long-term habitat oxygen conditions. This factor could be important in comparisons of inter- and intra-specific allometric gill functions and in the study of weight-specific oxygen consumption rates of decapod crustaceans.

scholarly journals The effects of intermittent exposure to low-pH and low-oxygen conditions on survival and growth of juvenile red abalone

2013 ◽  
Vol 10 (11) ◽  
pp. 7255-7262 ◽  
Author(s):  
T. W. Kim ◽  
J. P. Barry ◽  
F. Micheli
Keyword(s):  
Growth Rate ◽  
Individual Variation ◽  
Prolonged Exposure ◽  
Low Ph ◽  
Low Oxygen ◽  
Haliotis Rufescens ◽  
Oxygen Levels ◽  
Red Abalone ◽  
Intermittent Exposure ◽  
Oxygen Conditions

Abstract. Exposure of nearshore animals to hypoxic, low-pH waters upwelled from below the continental shelf and advected near the coast may be stressful to marine organisms and lead to impaired physiological performance. We mimicked upwelling conditions in the laboratory and tested the effect of fluctuating exposure to water with low-pH and/or low-oxygen levels on the mortality and growth of juvenile red abalone (Haliotis rufescens, shell length 5–10 mm). Mortality rates of juvenile abalone exposed to low-pH (7.5, total scale) and low-O2 (40% saturation, mg L−1) conditions for periods of 3 to 6 h every 3–5 days over 2 weeks did not differ from those exposed to control conditions (O2: 100% saturation, 12 mg L−1; pH 8.0). However, when exposure was extended to 24 h, twice over a 15-day period, juveniles experienced 5–20% higher mortality in the low-oxygen treatments compared to control conditions. Growth rates were reduced significantly when juveniles were exposed to low-oxygen and low-pH treatments. Furthermore, individual variation of growth rate increased when juveniles were exposed simultaneously to low-pH and low-O2 conditions. These results indicate that prolonged exposure to low-oxygen levels is detrimental for the survival of red abalone, whereas pH is a crucial factor for their growth. However, the high individual variation in growth rate under low levels of both pH and oxygen suggests that cryptic phenotypic plasticity may promote resistance to prolonged upwelling conditions by a portion of the population.

scholarly journals Long-term spatiotemporal variations in and expansion of low-oxygen conditions in the Pearl River estuary: a study synthesizing observations during 1976–2017

2021 ◽  
Vol 18 (18) ◽  
pp. 5247-5264
Author(s):  
Jiatang Hu ◽  
Zhongren Zhang ◽  
Bin Wang ◽  
Jia Huang
Keyword(s):  
Phytoplankton Biomass ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Oxygen Depletion ◽  
Pearl River ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
Bottom Waters ◽  
The Pearl River

Abstract. The Pearl River estuary (PRE) frequently experiences low-oxygen conditions in summer, with large-extent low-oxygen events and a long-term deoxygenation trend being reported recently. In this study, we provide a synthesis of the spatiotemporal patterns and incidence of different low-oxygen levels in the PRE based on the in situ observations collected from 1976 to 2017 and aim to elucidate the underlying mechanisms of low-oxygen conditions and their changes over the past 4 decades. The long-term observations show that the dissolved oxygen (DO) content in the PRE has had significant temporal variability and spatial heterogeneity. Low-oxygen conditions (DO < 4 mg L−1) have occurred mostly in the bottom waters of 5–30 m during summer and early autumn, with locations and severity varying substantially between years. Coastal waters from the southwest of Lantau Island to the northeast of the Wanshan Archipelago were identified as a hotspot area prone to subsurface low-oxygen conditions due to the combined effects of comparatively deep topography, a certain residence time and stability of the water column, and enhanced oxygen depletion related to high phytoplankton biomass. In addition, the low-oxygen waters, either directly imported from the upstream reaches or generated locally and further transported with the estuarine circulation, also had considerable impacts on the oxygen levels in the estuary. As for early autumn, marked low-oxygen conditions were present in both the surface and the bottom waters. A large area affected by low oxygen (∼ 4450 km2) was found in September 2006, where the low-oxygen conditions were comparable to the most severe ones observed in summer. The area was formed by the inflows of low-oxygen waters from the upstream reaches and enhanced oxygen depletion driven by an intricate coupling of physical and biogeochemical processes. Our analysis also reveals there has been an apparent expansion of the summertime low-oxygen conditions at the bottom of the PRE since the years around 2000, coincident with major environment changes in the Pearl River region. Overall, the PRE seems to be undergoing a transition from a system characterized by episodic, small-scale hypoxic events (DO < 2 mg L−1) to a system with seasonal, estuary-wide hypoxic conditions in summer. Although exacerbated eutrophication associated with anthropogenic nutrient inputs has generally been considered the primary cause for the deterioration of low-oxygen conditions in the PRE, the sharp decline in sediment load may play an important role as well via increasing water transparency and thereby supporting higher and broader phytoplankton biomass in the estuary.

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