Average Energy Budget Research Articles

Energy fluxes and vertical heat transfer in the Southern Baltic Sea

IntroductionThis study investigates the dynamics of energy fluxes and vertical heat transfer in the Southern Baltic Sea, emphasizing the significant role of the dicothermal layer in modulating the penetration of the thermocline and the propagation rates of thermal energy. The research aims to elucidate the complex patterns of solar energy absorption, its conversion into sea surface temperature (SST), and the transference of this energy deeper into the marine environment.MethodsData were collected through 93 monitoring cruises by the Institute of Oceanology of the Polish Academy of Sciences (IOPAN) from 1998 to 2023, using a high-resolution towed probe technique alongside Argo floats data for the Baltic Proper from 2020 to 2023. ERA5 climate reanalysis dataset and NEMOv4.0 ocean model forecasts were also utilized for a comprehensive analysis of VITE, Top Net Short-Wave Radiation, SST, and energy budget across the Southern Baltic Sea.Results and discussionThe Southern Baltic Sea functions as a net energy sink, with an average energy budget of 5.48 W m-2, predominantly absorbing energy during daylight and emitting it from September to February. A 59-day lag between peak solar energy and VITE peak was observed, followed by an additional 6-day delay before peak SST. The study further reveals a 15-day delay in temperature phase shift per 10 meters depth due to the dicothermal layer's influence on thermal energy propagation, extending to 35 days in the Central and Northern Baltic. Heat transfer is significantly affected by the levels of the thermocline and halocline, with regional variations in advection-driven seasonal signals. The pronounced thermal inertia and the critical role of the dicothermal layer underscore the complexity of thermal energy distribution in the Southern Baltic Sea.

Effects of the amplitude and frequency of salinity fluctuation on the body composition and energy budget of juvenile tongue sole (Cynoglossus semilaevis)

Effects of the amplitude (±2, ±4, ±6, and ±8) and frequency (2, 4, and 8 d) of salinity fluctuation on the body composition and energy budget of juvenile tongue sole (Cynoglossus semilaevis) were investigated in a 64-d experiment. Results showed that the amplitude and frequency of salinity fluctuation had significant interaction and both substantially affected the final weight and specific growth rate of juvenile tongue sole. The tongue sole exhibited better growth in treatments with moderate amplitude and frequency of salinity fluctuation (amplitude ±4–6; frequency 4–8 d) than in other treatments and the control. In terms of energy budget, salinity fluctuation strongly affected the proportions of energy components, including those deposited for growth and lost in respiration, feces, and excretion. Moderately amplitude and frequency of salinity fluctuationg that favored the growth of tongue sole partitioned more energy for growth and less energy for metabolism than the constant and other amplitude and frequency of salinity fluctuation. Average energy budget for tongue sole at moderately fluctuating salinity was determined to be 100C (food) = 30.92G (growth) + 10.30F (feces) + 6.77U (excretion) + 52.01R (respiration). Energetic advantage at moderately fluctuating salinity, including increased energy intake, high assimilation efficiency, reduced metabolism expenditure, and more energy partitioned into growth, might account for the enhancement of tongue sole growth. Commercial farmers are recommended to rear juvenile tongue sole with moderate salinity fluctuations for better growth performance of this species.

Effects of Ca and Mg concentrations in seawater on the growth and energy budget of juvenileParalichthys olivaceus(Temminck & Schlegel, 1846)

Summary Effects of seawater calcium (Ca) and magnesium (Mg) concentrations on the growth and energy budget of juvenile Paralichthys olivaceus (Temminck & Schlegel, 1846) were investigated at 20°C and a salinity of 30 psu. The Ca/Mg ratio (Ca : Mg = 1 : 3) in the experimental water was kept constant. Five treatments were set: C1, C2, C3, C4, and C5, and the Ca and Mg concentrations were 700, 1100, 1600, 2200, and 2800 (mg L−1), respectively. After a 60-day feeding trial the P. olivaceus survival rates were not affected significantly by Ca or Mg concentrations in the range of 700–2800 mg L−1. However, the specific growth rates (SGR) and weight gain (WG) of all treatments decreased with ascending Ca and Mg concentrations. The Ca and Mg concentrations had a strong influence on various energy parameters, namely, energy deposited for growth (G), energy lost for respiration (R), and energy lost in excretion (U), but had little influence on energy lost in feces (F). This indicated that the growth rate differences under different concentrations of Ca and Mg mainly resulted from differences of assimilation efficiency and energy channeled into respiration. The highest net growth efficiency was attained at the lowest concentration of Ca and Mg in seawater, and the higher concentrations of Ca and Mg increased the energy channeled to respiration and excretion, which led to significant reduction in growth. Therefore, the optimal growth of P. olivaceus could be obtained by regulating the concentration of Ca and Mg at 700 mg L−1, where the average energy budget was: 100C (100% energy consumed in food) = 47.21 (±0.63) G + 32.89 (±0.42) R + 16.71 (±0.56) F + 3.19 (±0.05) U.

Effect of salinity on growth and energy budget of red and green colour variant sea cucumberApostichopus japonicus(Selenca)

Sea cucumber, Apostichopus japonicus (Selenca), tolerates salinity fluctuations inhabiting intertide zone. This study deals with growth, food intake, food conversion and the bioenergetic responses of the red variant (wet weight of 2.60 ± 0.11g) and green variant (wet weight of 2.56 ± 0.08 g) A. japonicus to different salinities of 22, 26, 30, 34, and 38 psu at 16.5 ± 0.5°C. The results showed that salinity had a significant effect on specific growth rate (SGR) of both green and red variants A. japonicus (P 0.05). Values of adaptable salinity scope for green and red variants sea cucumber survival are 18.5~39 psu and 20.9~38.6 psu respectively. The average energy budget formula of sea cucumber at 30 psu was: 100C = 6G +42F +3U+49R (C, energy ingested; G, energy for growth; F, energy loss as faeces; U, energy used for ammonia excretion; R, energy loss for respiration). The sea cucumber had maximum energy ingested (C) and highest proportion of energy for growth (G) at 30 psu, and then decreased when salinity is above or below this salinity. Both red and green variants of A. japonicus deposited for growth were very low, and the energy loss in faeces and energy for respiration accounted for the majority of assimilation energy. The result clearly showed that the optimum condition for farming green and red variants A. japonicus, both with respect growth and energy allocation, is the salinity scope of 26 ~ 30 psu.

Effects of salinity on growth and energy budget of juvenile Penaeus monodon

A growth trial was conducted at 28.8 ± 1.8 °C to investigate the effect of salinity on survival rates, specific growth rates (SGR), food conversion efficiencies (FCE) and energy parameters of Penaeus monodon. Juveniles of P. monodon with average weight 1.20 ± 0.05 g were cultured at salinities of 5, 10, 15, 20, 25, 30 and 35 psu. Results showed that survival rates of P. monodon were not significantly affected by salinity in the range 10–35 psu. However, the lowest and significantly different ( p < 0.05) survival rate was observed at 5 psu. The highest SGR (3.24 ± 0.25%/d) and FCE (54.90 ± 2.97) were observed at 25 psu. Salinity had a strong influence on various energy parameters, namely energy deposited for growth ( G), energy lost for respiration ( R), energy lost in feces ( F), energy lost in excretion ( U) and energy lost in exuviae ( E), but had little influence on feeding rate (FR). It indicated that growth rate differences under different salinities were not resulted from differences of FR, but mainly resulted from differences of assimilation efficiency and energy channeled into respiration. The highest net growth efficiency was attained at 25 psu, and a salinity range outside 20–35 psu increased the energy channeled to respiration, excretion and exuviae, which led to significant reduction in growth and feed conversion efficiency. Therefore, the optimum salinity for the culture of P. monodon appeared to be ~ 25 psu, where the average energy budget was: 1OOC (100% energy consumed in food) = 14.51(± 1.05)G + 66.68(± 1.56)R + 14.54(± 0.72)F + 3.33(± 0.24)U + 0.93(± 0.07)E.

Effects of dietary sea mud and yellow soil on growth and energy budget of the sea cucumber Apostichopus japonicus (Selenka)

The effects of dietary sea mud or yellow soil (0, 20, 40, 60 and 80%) on growth and energy budget of the sea cucumber Apostichopus japonicus Selenka were studied. The results showed that there was no significant difference among growth of sea cucumbers fed diets containing the same proportion of sea mud and yellow soil. Sea cucumbers fed 20% sea mud or yellow soil obtained better growth than the other treatments ( P < 0.05). The ingestion rate (IR), feces production rate (FPR) and apparent digestive ratio (ADR) showed a descending trend as the percent of dietary sea mud or yellow soil increased, however, the specific growth rate (SGR) decreased when diets contained more than or less than 20% sea mud or yellow soil. The average energy budget formula was: 100 C = 4.27 G + 55.44 F + 3.69 U + 36.60 R. The energy deposited for growth was very low, and the energy loss in feces and energy for respiration accounted for the majority of the ingested energy. From economic and environmental points of views, it is feasible to add 20% yellow soil instead of sea mud to diets of sea cucumbers. This information should be helpful in the development of more appropriate diets for culture of holothurians.

Effect of Chronic Ammonia Exposure on Energy Budget of Juvenile Soft‐shelled Turtle, Pelodiscus sinensis

Abstract.— The present work investigated the effect of chronic ammonia exposure on energy budget of juvenile soft‐shelled turtle, Pelodiscus sinensis. Turtles (87.14 ± 4.00 g) were exposed to external total ammonia nitrogen (TAN) concentrations of C0 (11.01 mg/L), C1 (46.32 mg/L), C2 (68.71 mg/L), and C3 (97.0 mg/L), respectively, for 97 d at 29.5 C, pH 7.76. The ambient ammonia showed no significant influence on any component of the energy budget such as feed consumption, fecal production, excretion, standard metabolism, and growth. There were also no significant differences in body composition of the turtles among different treatments. Chronic exposure to ambient ammonia as high as 97 mg/L TAN did not affect energy budget of juvenile soft‐shelled turtle. The average energy budget for all turtles can be described as follows: 100 C = 9.3 F + 3.0 U + 74.6 R + 13.1 G, where C, F, U, R, and G represent energy intake, fecal energy, excretory energy loss, metabolism energy, and growth energy, respectively.

Growth and energy budget of F2‘all‐fish’ growth hormone gene transgenic common carp

The growth and energy budget for F2‘all‐fish’ growth hormone gene transgenic common carp Cyprinus carpio of two body sizes were investigated at 29·2° C for 21 days. Specific growth rate, feed intake, feed efficiency, digestibility coefficients of dry matter and protein, gross energy intake (IE), and the proportion of IE utilized for heat production (HE) were significantly higher in the transgenics than in the controls. The proportion of IE directed to waste products [faecal energy (FE) and excretory energy loss (ZE+UE) where ZE is through the gills and UE through the kidney], and the proportion of metabolizable energy (ME) for recovered energy (RE) were significantly lower in the transgenics than in the controls. The average energy budget equation of transgenic fish was as follows: 100 IE= 19·3 FE+ 6·0 (ZE+UE) + 45·2 HE+ 29·5 RE or 100 ME= 60·5 HE+ 39·5 RE. The average energy budget equation of the controls was: 100 IE= 25·2 FE+ 7·4 (ZE+UE) + 35·5 HE+ 31·9 RE or 100 ME= 52·7 HE+ 47·3 RE. These findings indicate that the high growth rate of ‘all‐fish’ transgenic common carp relative to their non‐transgenic counterparts was due to their increased feed intake, reduced lose of waste productions and improved feed efficiency. The benefit of the increased energy intake by transgenic fish, however, was diminished by their increased metabolism.