scholarly journals Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

2017 ◽  
Author(s):  
Sebastiaan Mestdagh ◽  
Leila Bagaço ◽  
Ulrike Braeckman ◽  
Tom Ysebaert ◽  
Bart De Smet ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Ecosystem Functioning ◽  
River Estuary ◽  
Functional Trait ◽  
Sediment Deposition ◽  
Sediment Chemistry ◽  
Sediment Layer ◽  
Sediment Reworking ◽  
Macrobenthic Communities ◽  
The Impact

Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna control sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bioirrigation, respectively. After incubation, the macrofauna was extracted, identified and counted, and classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motile animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bioirrigation and bioturbation activity showed increases in the lower sediment deposition regimes, but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motile, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

scholarly journals Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

2018 ◽  
Vol 15 (9) ◽  
pp. 2587-2599 ◽  
Author(s):  
Sebastiaan Mestdagh ◽  
Leila Bagaço ◽  
Ulrike Braeckman ◽  
Tom Ysebaert ◽  
Bart De Smet ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Ecosystem Functioning ◽  
River Estuary ◽  
Functional Trait ◽  
Sediment Deposition ◽  
Sediment Chemistry ◽  
Sediment Layer ◽  
Sediment Reworking ◽  
Macrobenthic Communities ◽  
The Impact

Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater–bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

scholarly journals The Impact of Exercise Serum on Selected Parameters of CD4+ T Cell Metabolism

Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 119-131
Author(s):  
Jana Palmowski ◽  
Kristina Gebhardt ◽  
Thomas Reichel ◽  
Torsten Frech ◽  
Robert Ringseis ◽  
...  
Keyword(s):  
T Cells ◽  
Oxygen Consumption ◽  
T Cell ◽  
Real Time ◽  
Cd4 T Cells ◽  
Cell Metabolism ◽  
Cd4 T Cell ◽  
Autologous Serum ◽  
Cell Phenotype ◽  
The Impact

CD4+ T cells are sensitive to peripheral changes of cytokine levels and metabolic substrates such as glucose and lactate. This study aimed to analyze whether factors released after exercise alter parameters of human T cell metabolism, specifically glycolysis and oxidative phosphorylation. We used primary human CD4+ T cells activated in the presence of autologous serum, which was collected before (CO) and after a 30-min exercise intervention (EX). In the course of activation, cells and supernatants were analyzed for cell viability and diameter, real-time oxygen consumption by using PreSens Technology, mRNA expression of glycolytic enzymes and complexes of the electron transport chain by real-time PCR, glucose, and lactate levels in supernatants, and in vitro differentiation by flow cytometry. EX did not alter T cell phenotype, viability, or on-blast formation. Similarly, no difference between CO and EX were found for CD4+ T cell activation and cellular oxygen consumption. In contrast, higher levels of glucose were found after 48 h activation in EX conditions. T cells activated in autologous exercise serum expressed lower HK1 mRNA and higher IFN-γ receptor 1. We suggest that the exercise protocol used was not sufficient to destabilize the immune metabolism of T cells. Therefore, more intense and prolonged exercise should be used in future studies.

scholarly journals Effects of temperature on the behaviour and metabolism of an intertidal foraminifera and consequences for benthic ecosystem functioning

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Noémie Deldicq ◽  
Dewi Langlet ◽  
Camille Delaeter ◽  
Grégory Beaugrand ◽  
Laurent Seuront ◽  
...  
Keyword(s):  
High Temperature ◽  
Ecosystem Functioning ◽  
Photosynthetic Activity ◽  
Species Traits ◽  
Biogeochemical Cycles ◽  
Variable Environment ◽  
Sediment Reworking ◽  
Temperature Regimes ◽  
Slow Moving ◽  
Effects Of Temperature

AbstractHeatwaves have increased in intensity, duration and frequency over the last decades due to climate change. Intertidal species, living in a highly variable environment, are likely to be exposed to such heatwaves since they can be emerged for more than 6 h during a tidal cycle. Little is known, however, on how temperature affects species traits (e.g. locomotion and behaviour) of slow-moving organisms such as benthic foraminifera (single-celled protists), which abound in marine sediments. Here, we examine how temperature influences motion-behaviour and metabolic traits of the dominant temperate foraminifera Haynesina germanica by exposing individuals to usual (6, 12, 18, 24, 30 °C) and extreme (high; i.e. 32, 34, 36 °C) temperature regimes. Our results show that individuals reduced their activity by up to 80% under high temperature regimes whereas they remained active under the temperatures they usually experience in the field. When exposed to a hyper-thermic stress (i.e. 36 °C), all individuals remained burrowed and the photosynthetic activity of their sequestered chloroplasts significantly decreased. Recovery experiments subsequently revealed that individuals initially exposed to a high thermal regime partially recovered when the hyper-thermic stress ceased. H. germanica contribution to surface sediment reworking substantially diminished from 10 mm3 indiv−1 day−1 (usual temperature) to 0 mm3 indiv−1 day−1 when individuals were exposed to high temperature regimes (i.e. above 32 °C). Given their role in sediment reworking and organic matter remineralisation, our results suggest that heatwaves may have profound long-lasting effects on the functioning of intertidal muddy ecosystems and some key biogeochemical cycles.

Oxygen supersaturation mitigates the impact of the regime of contaminated sediment reworking on sea urchin fertilization process

2020 ◽  
Vol 158 ◽  
pp. 104951 ◽  
Author(s):  
Nunzia Limatola ◽  
Iacopo Bertocci ◽  
Jong Tai Chun ◽  
Luigi Musco ◽  
Marco Munari ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Contaminated Sediment ◽  
Fertilization Process ◽  
Sediment Reworking ◽  
The Impact

scholarly journals The Acute Effects of Different Forms of Suspension Push‐Ups on Oxygen Consumption, Salivary Testosterone and Cortisol and Isometric Strength

2018 ◽  
Vol 64 (1) ◽  
pp. 77-85 ◽  
Author(s):  
David Bellar ◽  
Cory Etheredge ◽  
Lawrence W. Judge
Keyword(s):  
Oxygen Consumption ◽  
Repeated Measures ◽  
Bench Press ◽  
Body Height ◽  
Isometric Strength ◽  
Exercise Session ◽  
Acute Effects ◽  
Hands And Feet ◽  
The Impact ◽  
Push Up

Abstract Suspension exercise systems are being used in strength and conditioning facilities, fitness centers, rehabilitation centers and home gyms. Though some evidence exists regarding the impact of training with these systems, more work is needed for a better understanding. The purpose of the present investigation was to examine the acute effects of an exercise session with 2 (hands only) and 4 straps (hands and feet) in the push-up exercise compared to a work-matched bench press exercise session. The participants for this repeated measures, cross-over investigation were 18 healthy college-aged males (age: 24.8 ± 3.5 yrs, body mass: 81.8 ± 7.8 kg, body height: 178.9 ± 4.5 cm). The conditions were 6 sets of 10 repetitions of suspension push-ups using two straps (DUAL) for the hands, fours straps (QUAD) for hands and feet and a traditional bench press exercise matched to the average resistance during the suspension push-up. The participants performed all repetitions at a controlled cadence. Expired gases, and heart rate were monitored continuously during the exercise session. Pre and post exercise saliva samples were collected to quantify changes in testosterone and cortisol. Upper body isometric strength tests ( UBIST) were performed (Post, 1 hr, 24 hr, 48 hr) to evaluate changes in force production during recovery. Data analysis via repeated measures ANOVA revealed a significant trend for increased oxygen consumption in the QUAD condition compared to the bench press (p = 0.019). Additionally, both suspension conditions resulted in a reduced respiratory exchange ratio as compared to the bench press (p < 0.05). A significant main effect was noted for time in all conditions regarding isometric strength (p < 0.001), but no differences between conditions were revealed. Testosterone and cortisol responses did not differ between conditions. Based upon these data, it appears that when matched for work, suspension exercise results in equivalent reductions in muscle force, but greater oxygen consumption compared to isotonic exercise.

Simulation to Investigate the Reasons for the Sediment Deposition in the Upper Reach of the Deepwater Navigation Channel in the Changjiang River Estuary

2012 ◽  
Vol 610-613 ◽  
pp. 1237-1241
Author(s):  
Jie Gu ◽  
Wei Chen ◽  
Xin Qin ◽  
Dan Qing Ma ◽  
Xiao Li Wang ◽  
...  
Keyword(s):  
River Estuary ◽  
Sediment Deposition ◽  
Changjiang River ◽  
Changjiang River Estuary ◽  
The Changjiang River ◽  
The North ◽  
Velocity Magnitude ◽  
Navigation Channel ◽  
The Changjiang River Estuary ◽  
Set Up

At present, the upper reach of the Deepwater Navigation Channel is silted heavily, which brings negative influences on navigation. A two-dimensional numerical model is set up to simulate the hydrodynamics of the Changjiang River Estuary with Delft3D-FLOW in this paper. This model has been validated with the observed tidal level, flow velocity magnitude and direction, and the computed results agree well with the observed data, which also shows the model can well simulate the hydrodynamics of the Changjiang River Estuary caused by the Deepwater Navigation Channel Project. Based on the analysis of computed results, especially the velocity along the South Passage and North Passage, the flood and ebb flow in the Hengsha Passage, and the flow spilt ratio of South Passage and North Passage, it presents that one fundamental reason for the sediment deposition in the upper reach of the Deepwater Navigation Channel is that the velocity along the North Passage is far less than that along South Passage, above all, the velocity in North Passage upstream of the Hengsha Passage is even smaller; another reason is that the flood and ebb flow of Hengsha Passage are large, which weakens the water exchange between the North Passage and South Channel.

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