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 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.

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.

Pelagic oxygen consumption rates in the Elbe estuary: Proxies and spatial patterns.

2021 ◽  
Author(s):  
Justus E.E. van Beusekom ◽  
Dorothee Fehling ◽  
Sina Bold ◽  
Tina Sanders
Keyword(s):  
Organic Matter ◽  
Oxygen Consumption ◽  
Land Reclamation ◽  
Salinity Gradient ◽  
Elbe Estuary ◽  
Low Oxygen ◽  
Port Area ◽  
Consumption Rates ◽  
Gradient Based ◽  
The Elbe River

&lt;div&gt; &lt;div&gt;&lt;span&gt;The Elbe estuary is strongly impacted by human activities including dredging, land reclamation and eutrophication. Since about 30 years, water quality improved leading to major phytoplankton blooms in the Elbe river. When these blooms enter the upper estuary including the Hamburg port area, they collapse leading &amp;#160;to low oxygen conditions. During a cruise in September 2020 we measured oxygen consumption rates in water samples of the Elbe Estuary between the coastal North Sea (Wadden Sea) and &amp;#160;the weir in Geesthacht including a large freshwater part of the Elbe estuary. In addition, suspended matter samples were taken and analysed for chlorophyll, particulate C (PC) and particulate N (PN). Oxygen consumption rates reached maximum values at both the marine side (~0.3 &amp;#181;mol/(l*h)) and the freshwater &amp;#160;side of the estuary (~0.65 &amp;#181;mol/(l*h)) and a distinct minimum near the Estuarine Turbidity Maximum near the onset of the salinity gradient. Based on specific weights of phytoplankton and PC content, we estimated the contribution of newly formed organic matter. This estimate correlated significantly with the observed oxygen consumption rates. We suggest that most of the riverine organic matter is degraded within the freshwater part of the Elbe estuary before reaching the salinity gradient. This is in line with significant amounts of nitrate being released within the freshwater part of the estuary.&lt;/span&gt;&lt;/div&gt; &lt;/div&gt;

Energetics of Sablefish, Anoplopoma fimbria, under Laboratory Conditions

1982 ◽  
Vol 39 (7) ◽  
pp. 1012-1020 ◽  
Author(s):  
Kathleen M. Sullivan ◽  
Kenneth L. Smith Jr.
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Growth Rates ◽  
The Body ◽  
Fish Growth ◽  
Metabolic Rates ◽  
Anoplopoma Fimbria ◽  
Consumption Rates ◽  
Excretion Rates ◽  
Conversion Efficiencies

We measured respiration, growth, ingestion, and excretion rates for sablefish, Anoplopoma fimbria, collected off southern California at a depth of 500 m and maintained in the laboratory. We also measured the water, protein, and lipid content of white skeletal muscle in both laboratory-held and field fish. Sablefish fed a large ration (14% of wet body weight) every 7–10 d showed growth rates two to three times higher than known growth rates for field fish. On a reduced ration (4% of wet body weight) sablefish grew at rates similar to field fish, but white muscle composition varied significantly from field fish. Oxygen consumption rates under constant temperature conditions showed a decrease in the weight-specific oxygen consumption rates with increase in body weight, ranging from routine metabolic rates of 195.8 mg O2∙kg−1∙h−1 for a 0.25-kg fish to 60.8 mg O2∙kg−1∙h−1 for a 2.78-kg fish. Based on measurements of respiration and excretion, sablefish were estimated to have 162 d of energy stored in the body lipids and did not show signs of starvation stress with food deprivation up to 6 mo in the laboratory. Energy allocation shows very slow growth rates, low conversion efficiencies, and low metabolic rates as adjustments made to large, infrequent meals.Key words: physiological responses, benthopelagic fish, growth, metabolic rate, respiration, excretion

scholarly journals Hypoxic Transformation of Immune Cell Metabolism Within the Microenvironment of Oral Cancers

2020 ◽  
Vol 1 ◽  
Author(s):  
Amrita Chaudhary ◽  
Swarnendu Bag ◽  
Neeraj Arora ◽  
Vivek S. Radhakrishnan ◽  
Deepak Mishra ◽  
...  
Keyword(s):  
Tumor Cells ◽  
Immune Cells ◽  
Immune Cell ◽  
Cell Metabolism ◽  
Redox Homeostasis ◽  
Oxygen Depletion ◽  
Metabolic Reprogramming ◽  
Low Oxygen ◽  
Oral Cancers ◽  
Oxygen Conditions

Oral squamous cell carcinoma (OSCC) includes tumors of the lips, tongue, gingivobuccal complex, and floor of the mouth. Prognosis for OSCC is highly heterogeneous, with overall 5-year survival of ~50%, but median survival of just 8–10 months for patients with locoregional recurrence or metastatic disease. A key feature of OSCC is microenvironmental oxygen depletion due to rapid growth of constituent tumor cells, which triggers hypoxia-associated signaling events and metabolic adaptations that influence subsequent tumor progression. Better understanding of leukocyte responses to tissue hypoxia and onco-metabolite expression under low-oxygen conditions will therefore be essential to develop more effective methods of diagnosing and treating patients with OSCC. This review assesses recent literature on metabolic reprogramming, redox homeostasis, and associated signaling pathways that mediate crosstalk of OSCC with immune cells in the hypoxic tumor microenvironment. The likely functional consequences of this metabolic interface between oxygen-starved OSCC and infiltrating leukocytes are also discussed. The hypoxic microenvironment of OSCC modifies redox signaling and alters the metabolic profile of tumor-infiltrating immune cells. Improved understanding of heterotypic interactions between host leukocytes, tumor cells, and hypoxia-induced onco-metabolites will inform the development of novel theranostic strategies for OSCC.

Biogeochemical Controls on Coastal Hypoxia

2019 ◽  
Vol 11 (1) ◽  
pp. 105-130 ◽  
Author(s):  
Katja Fennel ◽  
Jeremy M. Testa
Keyword(s):  
Oxygen Depletion ◽  
Nutrient Loads ◽  
Low Oxygen ◽  
Basic Principles ◽  
Oxygen Minimum Zones ◽  
Coastal Systems ◽  
Oxygen Conditions ◽  
Anoxic Zones ◽  
Cross System ◽  
Oxygen Minimum

Aquatic environments experiencing low-oxygen conditions have been described as hypoxic, suboxic, or anoxic zones; oxygen minimum zones; and, in the popular media, the misnomer “dead zones.” This review aims to elucidate important aspects underlying oxygen depletion in diverse coastal systems and provides a synthesis of general relationships between hypoxia and its controlling factors. After presenting a generic overview of the first-order processes, we review system-specific characteristics for selected estuaries where adjacent human settlements contribute to high nutrient loads, river-dominated shelves that receive large inputs of fresh water and anthropogenic nutrients, and upwelling regions where a supply of nutrient-rich, low-oxygen waters generates oxygen minimum zones without direct anthropogenic influence. We propose a nondimensional number that relates the hypoxia timescale and water residence time to guide the cross-system comparison. Our analysis reveals the basic principles underlying hypoxia generation in coastal systems and provides a framework for discussing future changes.

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 Drivers of summer oxygen depletion in the central North Sea

2015 ◽  
Vol 12 (11) ◽  
pp. 8691-8722
Author(s):  
B. Y. Queste ◽  
L. Fernand ◽  
T. D. Jickells ◽  
K. J. Heywood ◽  
A. J. Hind
Keyword(s):  
Oxygen Consumption ◽  
Dissolved Oxygen ◽  
North Sea ◽  
Supply And Demand ◽  
Oxygen Depletion ◽  
High Rate ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Consumption Rates ◽  
Oxygenated Water

Abstract. In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow (&amp;approx; 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of CTD, dissolved oxygen concentrations, backscatter and fluorescence during a three day deployment. The high temporal resolution observations revealed occasional small scale events that supply oxygenated water into the bottom layer at a rate of 2±1 μmol dm−3 day−1. Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5±1 μmol dm−3 day−1. This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8±0.3 μmol dm−3 day−1 indicating a localised or short-lived increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localised depocentres and rapid remineralisation of resuspensded organic matter. The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date rates to be used in the development of ecosystem models.

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.

scholarly journals Microbial Consumption of Atmospheric Isoprene in a Temperate Forest Soil

1998 ◽  
Vol 64 (1) ◽  
pp. 172-177 ◽  
Author(s):  
C. C. Cleveland ◽  
J. B. Yavitt
Keyword(s):  
Atmospheric Chemistry ◽  
Temperate Forest ◽  
Temperature Response ◽  
Strong Relationship ◽  
Dry Weight ◽  
Low Oxygen ◽  
Oxygen Conditions ◽  
Consumption Rates ◽  
Microbial Consumption

ABSTRACT Isoprene (2-methyl-1,3 butadiene) is a low-molecular-weight hydrocarbon emitted in large quantities to the atmosphere by vegetation and plays a large role in regulating atmospheric chemistry. Until now, the atmosphere has been considered the only significant sink for isoprene. However, in this study we performed both in situ and in vitro experiments with soil from a temperate forest near Ithaca, N.Y., that indicate that the soil provides a sink for atmospheric isoprene and that the consumption of isoprene is carried out by microorganisms. Consumption occurred rapidly in field chambers (672.60 ± 30.12 to 2,718.36 ± 86.40 pmol gdw−1 day−1) (gdw is grams [dry weight] of soil; values are means ± standard deviations). Subsequent laboratory experiments confirmed that isoprene loss was due to biological processes: consumption was stopped by autoclaving the soil; consumption rates increased with repeated exposure to isoprene; and consumption showed a temperature response consistent with biological activity (with an optimum temperature of 30°C). Isoprene consumption was diminished under low oxygen conditions (120 ± 7.44 versus 528.36 ± 7.68 pmol gdw−1 day−1 under ambient O2concentrations) and showed a strong relationship with soil moisture. Isoprene-degrading microorganisms were isolated from the site, and abundance was calculated as 5.8 × 105 ± 3.2 × 105 cells gdw−1. Our results indicate that soil may provide a significant biological sink for atmospheric isoprene.

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