Turbulent flow reduces oxygen consumption in the labriform swimming shiner perch, Cymatogaster aggregata

Fish swimming energetics are often measured in laboratory environments which attempt to minimize turbulence, though turbulent flows are common in the natural environment. To test whether the swimming energetics and kinematics of shiner perch Cymatogaster aggregata (a labriform swimmer) were affected by turbulence, two flow conditions were constructed in a swim-tunnel respirometer. A low-turbulence flow was created using a common swim-tunnel respirometry setup with a flow straightener and fine-mesh grid to minimize velocity fluctuations. A high-turbulence flow condition was created by allowing large velocity fluctuations to persist without a flow straightener or fine grid. The two conditions were tested with Particle Image Velocimetry to confirm significantly different turbulence properties throughout a range of mean flow speeds. Oxygen consumption rates of the swimming fish increased with swimming speeds and pectoral fin beat frequencies in both flow conditions. Higher turbulence also caused a greater positional variability in swimming individuals (vs. low-turbulence flow) at medium and high speeds. Surprisingly, fish used less oxygen in high turbulence compared to low-turbulence flow at medium and high swimming speeds. Simultaneous measurements of swimming kinematics indicated that these reductions in oxygen consumption could not be explained by specific known flow-adaptive behaviours such as Kármán-gaiting or entraining. Therefore, fish in high-turbulence flow may take advantage of the high variability in turbulent energy through time. These results suggest that swimming behavior and energetics measured in the lab in straightened flow, typical of standard swimming respirometers, might differ from that of more turbulent, semi-natural flow conditions.PostprintPeer reviewe

Intraspecific individual variation of temperature tolerance associated with oxygen demand in the European sea bass (Dicentrarchus labrax)

The European sea bass (Dicentrarchus labrax) is an economically important fish native to the Mediterranean and Northern Atlantic. Its complex life cycle involves many migrations through temperature gradients that affect the energetic demands of swimming. Previous studies have shown large intraspecific variation in swimming performance and temperature tolerance, which could include deleterious and advantageous traits under the evolutionary pressure of climate change. However, little is known of the underlying determinants of this individual variation. We investigated individual variation in temperature tolerance in 30 sea bass by exposing them to a warm temperature challenge test. The eight most temperature-tolerant and eight most temperature-sensitive fish were then studied further to determine maximal swimming speed (U-CAT), aerobic scope and post-exercise oxygen consumption. Finally, ventricular contractility in each group was determined using isometric muscle preparations. The temperature-tolerant fish showed lower resting oxygen consumption rates, possessed larger hearts and initially recovered from exhaustive exercise faster than the temperature-sensitive fish. Thus, whole-animal temperature tolerance was associated with important performance traits. However, the temperature-tolerant fish also demonstrated poorer maximal swimming capacity (i.e. lower UCAT) than their temperature-sensitive counterparts, which may indicate a trade-off between temperature tolerance and swimming performance. Interestingly, the larger relative ventricular mass of the temperature-tolerant fish did not equate to greater ventricular contractility, suggesting that larger stroke volumes, rather than greater contractile strength, may be associated with thermal tolerance in this species

Estilos de vida y factores biosocioculturales del adulto mayor, asentamiento humano Santa Rosa del Sur, Chimbote, 2015

TesisLa investigación tuvo como objetivo general determinar la relación entre el estilo de vida y los factores biosocioculturales del adulto mayor. La investigación fue cuantitativo - descriptivo correlacional, con una muestra de 217 adultos mayores, a quienes se le aplicó la escala del estilo de vida y el cuestionario sobre factores biosocioculturales. Los datos fueron procesados con el Software SPSS versión 18.0. Para establecer la relación entre las variables de estudio se aplicó la prueba de independencia de criterios Chi cuadrado, con el 95% de confiabilidad y significancia de p< 0.05. Se obtuvieron los siguientes resultados: Casi la totalidad de los adultos mayores del A.H Santa Rosa del sur segunda etapa presentan un estilo de vida no saludable y un porcentaje mínimo saludable. En relación a los factores biosocioculturales tenemos que: La mayoría de los adultos mayores son de sexo femenino, con grado de instrucción primaria, de religión católica, de ocupación ama de casa, y con un ingreso económico de 400 a 650 nuevo soles, y menos de la mitad son de estado civil casado. En los factores biosocioculturales del adulto mayor no cumple relación estadísticamente significativa entre el estilo de vida y los factores biosocioculturales: Sexo, grado de instrucción, religión, estado civil, ocupación e ingreso económico

Individual variation in whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance in a marine teleost

International audienceHypoxia is a pervasive problem in coastal environments and is predicted to have enduring impacts on aquatic ecosystems. Intraspecific variation in hypoxia tolerance is well documented in fish; however, the factors underlying this variation remain unknown. Here, we investigate the role of the heart in individual hypoxia tolerance of the European sea bass (Dicentrarchus labrax). We found individual whole-animal hypoxia tolerance is a stable trait in sea bass for more than 18 months (duration of study). We next examined in vitro cardiac performance and found myocardial muscle from hypoxia-tolerant individuals generated greater force, with higher rates of contraction and relaxation, than hypoxic-sensitive individuals during hypoxic exposure. Thus, whole-animal hypoxia tolerance is associated with cardiac hypoxia tolerance. As the occurrence of aquatic hypoxia is expected to increase in marine ecosystems, our experimental data suggest that cardiac performance may influence fish survival and distribution

Turbulent flow reduces oxygen consumption in the labriform swimming shiner perch, <i>Cymatogaster aggregata</i>

Fish swimming energetics are often measured in laboratory environments which attempt to minimize turbulence, though turbulent flows are common in the natural environment. To test whether the swimming energetics and kinematics of shiner perch Cymatogaster aggregata (a labriform swimmer) were affected by turbulence, two flow conditions were constructed in a swim-tunnel respirometer. A low-turbulence flow was created using a common swim-tunnel respirometry setup with a flow straightener and fine-mesh grid to minimize velocity fluctuations. A high-turbulence flow condition was created by allowing large velocity fluctuations to persist without a flow straightener or fine grid. The two conditions were tested with Particle Image Velocimetry to confirm significantly different turbulence properties throughout a range of mean flow speeds. Oxygen consumption rates of the swimming fish increased with swimming speeds and pectoral fin beat frequencies in both flow conditions. Higher turbulence also caused a greater positional variability in swimming individuals (vs. low-turbulence flow) at medium and high speeds. Surprisingly, fish used less oxygen in high turbulence compared to low-turbulence flow at medium and high swimming speeds. Simultaneous measurements of swimming kinematics indicated that these reductions in oxygen consumption could not be explained by specific known flow-adaptive behaviours such as Kármán-gaiting or entraining. Therefore, fish in high-turbulence flow may take advantage of the high variability in turbulent energy through time. These results suggest that swimming behavior and energetics measured in the lab in straightened flow, typical of standard swimming respirometers, might differ from that of more turbulent, semi-natural flow conditions

ENVRI-FAIR D2.2: ENVRI Community building, engagement and communications strategy

This document presents a strategy for ENVRI community communication and engagement actions. Such activities aim to further build the community of environmental research infrastructures (RI), with a special eye on the engagement of the RI scientific communities. The idea is to promote the RI collaboration benefits and inform about the opportunities offered thanks to the integrative and harmonization work among the RIs. However, the main goal of this strategy is to increase the visibility and two-way communications and engagement of the external stakeholders for the benefit of the ENVRI community as much as the collaborating RIs. This deliverable presents a summary of communications activities that are more possible, effective, or economical to do together rather than by individual member research infrastructures. We hope that such activities will increase the understanding of the Earth system's complexity and the necessity of studying the system holistically and the understanding of each specific RI's role in that system. Since such understanding is very much dependent on the in-situ observations, i.e., on the environmental RIs, the goal of the communications activities is to put the data and services provided by the RIs into the spotlight, and in that way attract more users, and eventually deliver a top-level multidisciplinary science