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Factors Affecting Fish Growth and Production
Published in Hillary S. Egna, Claude E. Boyd, Dynamics of POND Aquaculture, 2017
Bioenergetics is the study of the energy budget by which ingested energy is partitioned into energy lost as feces or excretory products and energy used for maintenance, activity and growth or the elaboration of new body tissues. Fish growth can be expressed in terms of energy partitioning as follows: I = M + G + E where I = ingested food energy, M = energy expended for metabolism, G = energy expended for growth and E = energy excreted (Jobling, 1994). Growth may be further partitioned into somatic and gonadal components. Thus, bioenergetics is the physiological framework for the relationship between feeding and growth.
Drought Assessment and Management for Heat Waves Monitoring
Published in Saeid Eslamian, Faezeh Eslamian, Handbook of Drought and Water Scarcity, 2017
Nicolas R. Dalezios, Saeid Eslamian
Heat is a feeling of discomfort. Heat generally means thermal discomfort, which activates the thermoregulatory system of the body. Continuous heat increases the discomfort and may cause adverse effects on health, particularly when combined with high levels of humidity or when exacerbated by a person’s physical condition. If heat lasts for several days or longer, it is called a heat wave. In the mid and high latitudes, heat waves are embedded in the usual course of the summer weather, whereas in the tropics they are endemic. Quantification of heat needs the total energy budget of the human body. This energy budget is influenced by air temperature, humidity, ventilation, radiation, bodily activity, clothing, mass and shape of the body, health state, age, and individual predisposition. In the case of overheating, the body’s thermoregulatory system fails to keep the temperature within a tolerable range in the core parts of the body. Indicators in use allow a simplified description of the energy budget of the human body, in addition to capturing effects of heat. These indicators classify the environmental conditions by either recommending the type of feasible bodily activity or requiring the cooling of the human body, both in order to avoid health damage due to overheating.
Antarctic Marine Biodiversity: Adaptations, Environments and Responses to Change
Published in S. J. Hawkins, A. J. Evans, A. C. Dale, L. B. Firth, I. P. Smith, Oceanography and Marine Biology, 2018
All of the major processes in an energy budget (covering all of the energy used by the organism) have an associated metabolic cost accrued when ATP is used in that process. In fully aerobic conditions, this can be measured via oxygen consumption (MO2), and oxygen consumption is a measure of the immediate energy requirement under these conditions. Following the rationale laid out in Clarke (1987a), the energy budget then becomes: C=F+Ps+Rs+Pr+Rr+Rm+Ra+U+Mwhere Rs represents the respiratory costs associated with somatic production, Rr is the respiratory costs of reproductive production, Rm is maintenance metabolic cost and Ra is respiratory costs associated with activity. From the previous equation, it is clear that measured oxygen uptake in an organism is a complex entity made up of several costs (Rs + Rr + Rm + Ra) from a range of sources (Clarke 1987a).
Evaluation and spatio-temporal analysis of surface energy flux in permafrost regions over the Qinghai-Tibet Plateau and Arctic using CMIP6 models
Published in International Journal of Digital Earth, 2022
Junjie Ma, Ren Li, Zhongwei Huang, Tonghua Wu, Xiaodong Wu, Lin Zhao, Hongchao Liu, Guojie Hu, Yao Xiao, Yizhen Du, Shuhua Yang, Wenhao Liu, Yongliang Jiao, Shenning Wang
The Bowen ratio is the ratio of sensible to latent heat flux. It summarizes how the energy budget is partitioned between H and LE. The available energy shifts more towards the H with an increasing Bowen ratio (Eugster et al. 2000; Hu et al. 2019; Gu et al. 2015). In the Arctic, spring is more appropriately called light winter, in which shortwave radiation increases gradually. The increment is not significant due to the high snow albedo. At this stage, the energy budget is similar to that in winter. The average negative sensible heat flux is balanced with the long-wave radiation. The latent heat flux occupies an insignificant position in the energy budget (Figure 6a), Furthermore, the Bowen ratio is negative for most of the Arctic (Figure 10a). The snow and active layer start to melt during this period. The latent heat flux also increases with increasing surface soil moisture content. The summer period has strong shortwave radiation, the snow cover is the least (Serreze et al. 2007). The net shortwave radiation is balanced with the net longwave radiation, H, LE, and ground heat flux, leading to the thawing of the active layer in permafrost regions. The average Bowen ratio is close to one. However, it varies widely from 0.5–2 in different regions (Figure 10b). This is primarily related to the local surface soil moisture content (Westermann et al. 2009). The shortwave radiation decreases sharply in autumn, and the snow cover for a longer period of time has not yet formed. During this period, the H shifts towards negative values (Figure 8c). However, the freezing of active layer soil does not begin completely. Shortwave radiation in winter is approximately zero owing to the arrival of the polar night. At this time, the longwave radiation dominates the system. Longwave radiation is primarily balanced by negative H, which heats the land surface and cools the atmosphere. The LE has only minor importance in the energy balance during this period.