Oxygen Consumption of Resuspended Sediments of the Upper Elbe Estuary: Process Identification and Prognosis

AbstractThe resuspension of sediment leads to an increased release of nutrients and organic substances into the overlying water column, which can have a negative effect on the oxygen budget. Especially in the warmer months with a lower oxygen saturation and higher biological activity, the oxygen content can reach critical thresholds in estuaries like the upper Elbe estuary. Many studies have dealt with the nutrient fluxes that occur during a resuspension event. However, the sediment properties that influence the oxygen consumption potential (OCP) and the different biochemical processes have not been examined in detail. To fill this gap, we investigated the biogeochemical composition, texture, and OCP of sediments at 21 locations as well as the temporal variability within one location for a period of 2 years (monthly sampling) in the upper Elbe estuary. The OCP of sediments during a seven-day resuspension event can be described by the processes of sulphate formation, nitrification, and mineralisation. Chlorophyll, total nitrogen (Ntotal), and total organic carbon showed the highest correlations with the OCP. Based on these correlations, we developed a prognosis model to calculate the OCP for the upper Elbe estuary with a single sediment parameter (Ntotal). The model is well suited to calculate the oxygen consumption of resuspended sediments in the Hamburg port area during the relevant warmer months and shows a normalised root mean squared error of < 0.11 ± 0.13. Thus, the effect of maintenance measures such as water injection dredging and ship-induced wave on the oxygen budget of the water can be calculated.

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

10.5194/egusphere-egu21-8699 ◽

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

<div> <div><span>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 &#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 &#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 &#181;mol/(l*h)) and the freshwater &#160;side of the estuary (~0.65 &#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.</span></div> </div>

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Interactions of dietary fat and 2,5-anhydro-d-mannitol on energy metabolism in isolated rat hepatocytes

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00159.2001 ◽

2002 ◽

Vol 282 (3) ◽

pp. R715-R720 ◽

Cited By ~ 9

Author(s):

Hong Ji ◽

Grazyna Graczyk-Milbrandt ◽

Mary D. Osbakken ◽

Mark I. Friedman

Keyword(s):

Oxygen Consumption ◽

Rat Hepatocytes ◽

Isolated Hepatocytes ◽

Metabolic Effects ◽

Atp Content ◽

Isolated Rat Hepatocytes ◽

Palmitate Oxidation ◽

Low Carbohydrate ◽

Lower Oxygen ◽

Hepatocyte Metabolism

The fructose analog 2,5-anhydro-d-mannitol (2,5-AM) stimulates feeding in rats by reducing ATP content in the liver. These behavioral and metabolic effects occur with rats fed a high-carbohydrate/low-fat (HC/LF) diet, but they are prevented or attenuated when the animals eat high-fat/low-carbohydrate (HF/LC) food. To examine the metabolic bases for this effect of diet, we assessed the actions of 2,5-AM on ATP content, oxygen consumption, and substrate oxidation in isolated hepatocytes from rats fed one of the two diets. Compared with cells from rats fed the HC/LF diet (“HC/LF” cells), cells from rats fed the HF/LC diet (“HF/LC” cells) had similar ATP contents but lower oxygen consumption, decreased fructose, and increased palmitate oxidation. 2,5-AM did not decrease ATP content or oxygen consumption in HF/LC cells as much as it did in HC/LF hepatocytes, and it only affected fructose and palmitate oxidation in HC/LF cells.31P-NMR spectroscopy indicated that differences in phosphate trapping accounted for differences in depletion of ATP by 2,5-AM. These results suggest that intake of the HF/LC diet prevents the eating response and attenuates the decline in liver ATP by shifting hepatocyte metabolism to favor fat over carbohydrate as an energy-yielding substrate.

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Adaptation to oxygen deprivation in cultures of human pluripotent stem cells, endothelial progenitor cells, and umbilical vein endothelial cells

AJP Cell Physiology ◽

10.1152/ajpcell.00484.2009 ◽

2010 ◽

Vol 298 (6) ◽

pp. C1527-C1537 ◽

Cited By ~ 70

Author(s):

Hasan Erbil Abaci ◽

Rachel Truitt ◽

Eli Luong ◽

German Drazer ◽

Sharon Gerecht

Keyword(s):

Stem Cells ◽

Endothelial Cells ◽

Oxygen Consumption ◽

Progenitor Cells ◽

Pluripotent Stem Cells ◽

Cell Types ◽

Cellular Responses ◽

Glut 1 ◽

Lower Oxygen ◽

Oxygen Tensions

Hypoxia plays an important role in vascular development through hypoxia-inducible factor-1α (HIF-1α) accumulation and downstream pathway activation. We sought to explore the in vitro response of cultures of human embryonic stem cells (hESCs), induced pluripotent stem cells (iPSCs), human endothelial progenitor cells (hEPCs), and human umbilical cord vein endothelial cells (HUVECs) to normoxic and hypoxic oxygen tensions. We first measured dissolved oxygen (DO) in the media of adherent cultures in atmospheric (21% O2), physiological (5% O2), and hypoxic oxygen conditions (1% O2). In cultures of both hEPCs and HUVECs, lower oxygen consumption was observed when cultured in 1% O2. At each oxygen tension, feeder-free cultured hESCs and iPSCs were found to consume comparable amounts of oxygen. Transport analysis revealed that the oxygen uptake rate (OUR) of hESCs and iPSCs decreased distinctly as DO availability decreased, whereas the OUR of all cell types was found to be low when cultured in 1% O2, demonstrating cell adaptation to lower oxygen tensions by limiting oxygen consumption. Next, we examined HIF-1α accumulation and the expression of target genes, including VEGF and angiopoietins ( ANGPT; angiogenic response), GLUT-1 (glucose transport), BNIP3, and BNIP3L (autophagy and apoptosis). Accumulations of HIF-1α were detected in all four cell lines cultured in 1% O2. Corresponding upregulation of VEGF, ANGPT2, and GLUT-1 was observed in response to HIF-1α accumulation, whereas upregulation of ANGPT1 was detected only in hESCs and iPSCs. Upregulation of BNIP3 and BNIP3L was detected in all cells after 24-h culture in hypoxic conditions, whereas apoptosis was not detectable using flow cytometry analysis, suggesting that BNIP3 and BNIP3L can lead to cell autophagy rather than apoptosis. These results demonstrate adaptation of all cell types to hypoxia but different cellular responses, suggesting that continuous measurements and control over oxygen environments will enable us to guide cellular responses.

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The Relation of Animal Size to Oxygen Consumption in Some Fresh-Water Turbellarian Worms

Journal of Experimental Biology ◽

10.1242/jeb.19.2.168 ◽

1942 ◽

Vol 19 (2) ◽

pp. 168-175

Author(s):

R. J. WHITNEY

Keyword(s):

Oxygen Consumption ◽

Fresh Water ◽

Unit Weight ◽

Size Factor ◽

Small Animals ◽

Lower Oxygen ◽

The Law ◽

Animal Size

1. A size factor is demonstrated for the oxygen consumption at 14.5° C. of four species of fresh-water Turbellaria obtained from different habitats. 2. For three of the species studied (Polycelis cornuta, Crenobia alpina and Planaria polychroa) small animals were found to have a higher oxygen consumption per unit weight than large ones. In the case of Polycelis nigra small animals were shown to have a lower oxygen consumption per unit weight than large ones. 3. The adherence of the size factor to the surface law of Rubner is discussed. Only Crenobia alpina satisfies the theoretical requirements of the law, and in this species it is shown that the size factor is practically unchanged when the oxygen consumptions are determined at 7.0° C. instead of 14.5° C.

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Oxygen migration through a cover with capillary barrier effects colonized by roots

Canadian Geotechnical Journal ◽

10.1139/cgj-2019-0515 ◽

2020 ◽

Vol 57 (12) ◽

pp. 1903-1914 ◽

Cited By ~ 1

Author(s):

Alex Proteau ◽

Marie Guittonny ◽

Bruno Bussière ◽

Abdelkabir Maqsoud

Keyword(s):

Oxygen Consumption ◽

Root Colonization ◽

Mine Drainage ◽

Root Length Density ◽

Mixed Forest ◽

Capillary Barrier ◽

Barrier Effects ◽

Lower Oxygen ◽

Oxygen Migration ◽

Reactivity Coefficient

Covers with capillary barrier effects (CCBEs) are multi-layered oxygen barrier covers used in humid climates to reclaim reactive mine tailings and limit the generation of acid mine drainage. Once constructed, CCBEs are colonized by surrounding plants. Roots modify water storage and respire oxygen. The performance of CCBEs could evolve over time due to root colonization. Twenty-five plots with varying vegetation were investigated at a 17-year-old CCBE in the mixed forest of Quebec, Canada. Geotechnical parameters and root colonization of the moisture-retaining layer (MRL) of the CCBE were characterized. The performance of the MRL to control oxygen migration was assessed using oxygen consumption tests and numerical modeling. Despite root colonization at the surface of the MRL, oxygen fluxes generally complied with the CCBE’s design criteria. Root presence created oxygen consumption in the MRL, which could be expressed with a reactivity coefficient (Kr). A positive correlation (R2 = 0.65) was found between root length density and Kr. Oxygen consumption by root respiration helped to lower oxygen fluxes by 0.5 to 76 g/m2/year, with a mean of 13 g/m2/year. These results will help to better understand the influence of roots on CCBEs’ performance to control oxygen migration.

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The Respiratory Physiology of the Marine Nematodes Enoplus Brevis (Bastian) and E. Communis (Bastian)

Journal of Experimental Biology ◽

10.1242/jeb.59.1.267 ◽

1973 ◽

Vol 59 (1) ◽

pp. 267-274

Author(s):

H. J. ATKINSON

Keyword(s):

Oxygen Consumption ◽

Sea Water ◽

Atmospheric Oxygen ◽

Respiratory Physiology ◽

Marine Nematodes ◽

Oxygen Regime ◽

Lower Oxygen ◽

Rate Of Oxygen Consumption ◽

Oxygen Tensions ◽

Oxygen Requirements

1. The rate of oxygen consumption of individual male Enoplus brevis and E. communis was measured at 15 °C, after altering the oxygen regime experienced since the animals were collected. 2. When both E. brevis and E. communis were transferred to 35 Torr from atmospheric oxygen tensions, their oxygen consumption was only two-thirds of that of individuals maintained at this lower oxygen tension. 3. The rate of oxygen consumption of the two species at 135 Torr was unaltered by exposure for 2 h to oxygen-free sea water. 4. The results are discussed in relation to the overall influence of fluctuating oxygen regimes on the oxygen requirements of nematodes.

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NFκB Regulates Muscle Development and Mitochondrial Function

The Journals of Gerontology Series A ◽

10.1093/gerona/gly262 ◽

2018 ◽

Vol 75 (4) ◽

pp. 647-653 ◽

Cited By ~ 4

Author(s):

Joseph M Valentine ◽

Mengyao E Li ◽

Steven E Shoelson ◽

Ning Zhang ◽

Robert L Reddick ◽

...

Keyword(s):

Oxygen Consumption ◽

Life Span ◽

Muscle Mass ◽

Mitochondrial Function ◽

Muscle Development ◽

Tissue Mass ◽

Lower Oxygen ◽

Consumption Rates ◽

Nfκb Pathway ◽

Gastrocnemius Muscles

Abstract Nuclear factor (NF)κB is a transcription factor that controls immune and inflammatory signaling pathways. In skeletal muscle, NFκB has been implicated in the regulation of metabolic processes and tissue mass, yet its affects on mitochondrial function in this tissue are unclear. To investigate the role of NFκB on mitochondrial function and its relationship with muscle mass across the life span, we study a mouse model with muscle-specific NFκB suppression (muscle-specific IκBα super-repressor [MISR] mice). In wild-type mice, there was a natural decline in muscle mass with aging that was accompanied by decreased mitochondrial function and mRNA expression of electron transport chain subunits. NFκB inactivation downregulated expression of PPARGC1A, and upregulated TFEB and PPARGC1B. NFκB inactivation also decreased gastrocnemius (but not soleus) muscle mass in early life (1–6 months old). Lower oxygen consumption rates occurred in gastrocnemius and soleus muscles from young MISR mice, whereas soleus (but not gastrocnemius) muscles from old MISR mice displayed increased oxygen consumption compared to age-matched controls. We conclude that the NFκB pathway plays an important role in muscle development and growth. The extent to which NFκB suppression alters mitochondrial function is age dependent and muscle specific. Finally, mitochondrial function and muscle mass are tightly associated in both genotypes and across the life span.

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An artificial neural network to estimate physical activity energy expenditure and identify physical activity type from an accelerometer

Journal of Applied Physiology ◽

10.1152/japplphysiol.00465.2009 ◽

2009 ◽

Vol 107 (4) ◽

pp. 1300-1307 ◽

Cited By ~ 221

Author(s):

John Staudenmayer ◽

David Pober ◽

Scott Crouter ◽

David Bassett ◽

Patty Freedson

Keyword(s):

Physical Activity ◽

Oxygen Consumption ◽

Confidence Interval ◽

Mean Squared Error ◽

Temporal Dynamics ◽

Accelerometer Data ◽

Ann Model ◽

Activity Type ◽

Metabolic Equivalents ◽

Artificial Neural

The aim of this investigation was to develop and test two artificial neural networks (ANN) to apply to physical activity data collected with a commonly used uniaxial accelerometer. The first ANN model estimated physical activity metabolic equivalents (METs), and the second ANN identified activity type. Subjects ( n = 24 men and 24 women, mean age = 35 yr) completed a menu of activities that included sedentary, light, moderate, and vigorous intensities, and each activity was performed for 10 min. There were three different activity menus, and 20 participants completed each menu. Oxygen consumption (in ml·kg−1·min−1) was measured continuously, and the average of minutes 4–9 was used to represent the oxygen cost of each activity. To calculate METs, activity oxygen consumption was divided by 3.5 ml·kg−1·min−1 (1 MET). Accelerometer data were collected second by second using the Actigraph model 7164. For the analysis, we used the distribution of counts (10th, 25th, 50th, 75th, and 90th percentiles of a minute's second-by-second counts) and temporal dynamics of counts (lag, one autocorrelation) as the accelerometer feature inputs to the ANN. To examine model performance, we used the leave-one-out cross-validation technique. The ANN prediction of METs root-mean-squared error was 1.22 METs (confidence interval: 1.14–1.30). For the prediction of activity type, the ANN correctly classified activity type 88.8% of the time (confidence interval: 86.4–91.2%). Activity types were low-level activities, locomotion, vigorous sports, and household activities/other activities. This novel approach of applying ANNs for processing Actigraph accelerometer data is promising and shows that we can successfully estimate activity METs and identify activity type using ANN analytic procedures.

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Effects of cyanobacterial-driven pH increases on sediment nutrient fluxes and coupled nitrification-denitrification in a shallow fresh water estuary

Biogeosciences ◽

10.5194/bg-9-2697-2012 ◽

2012 ◽

Vol 9 (7) ◽

pp. 2697-2710 ◽

Cited By ~ 57

Author(s):

Y. Gao ◽

J. C. Cornwell ◽

D. K. Stoecker ◽

M. S. Owens

Keyword(s):

Oxygen Consumption ◽

Pore Water ◽

Soluble Reactive Phosphorus ◽

Inorganic Phosphorus ◽

Cyanobacterial Blooms ◽

Ph Effects ◽

Overlying Water ◽

High Ph ◽

Total Ammonium ◽

Water Ecosystems

Abstract. Summer cyanobacterial blooms caused an elevation in pH (9 to ~10.5) that lasted for weeks in the shallow and tidal-fresh region of the Sassafras River, a tributary of Chesapeake Bay (USA). Elevated pH promoted desorption of sedimentary inorganic phosphorus and facilitated conversion of ammonium (NH4+) to ammonia (NH3). In this study, we investigated pH effects on exchangeable NH4+ desorption, pore water diffusion and the flux rates of NH4+, soluble reactive phosphorus (SRP) and nitrate (NO3−), nitrification, denitrification, and oxygen consumption. Elevated pH enhanced desorption of exchangeable NH4+ through NH3 formation from both pore water and adsorbed NH4+ pools. Progressive penetration of high pH from the overlying water into sediment promoted the mobility of SRP and the release of total ammonium (NH4+ and NH3) into the pore water. At elevated pH levels, high sediment-water effluxes of SRP and total ammonium were associated with reduction of nitrification, denitrification and oxygen consumption rates. Alkaline pH and the toxicity of NH3 may inhibit nitrification in the thin aerobic zone, simultaneously constraining coupled nitrification–denitrification with limited NO3− supply and high pH penetration into the anaerobic zone. Geochemical feedbacks to pH elevation, such as enhancement of dissolved nutrient effluxes and reduction in N2 loss via denitrification, may enhance the persistence of cyanobacterial blooms in shallow water ecosystems.

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