Variation in the calorific value and total energy content of the lesser sandeel (Ammodytes marinus) and other fish preyed on by seabirds

Wet and dry calorific values (energy densities) and total energy content of lesser sandeel Ammodytes marinus , sprat Sprattus sprattus , Atlantic herring Clupea harengus , whiting Merlangius merlangus , saithe Pollachius virens and cod Gadus morhua , were measured. Calorific values varied both within and between species. Larger fish tended to have higher calorific values than small ones, particularly when considered in terms of wet weight, but there was considerable temporal variation. The calorific values and body weights of sandeels larger than 10 cm showed marked seasonal trends and in consequence the total energy content of a sandeel of given length in summer is approximately double the spring value. The calorific values of herring and sprat also varied from month to month but seasonal cycles were less obvious. Whiting varied least. Both calorific values and total energy content of individual sprat were very variable in summer (the spawning season of this species). Because there is so much intraspecific variation, care must be taken when assessing the relative merits (in terms of energy) of different species as prey. The practical difficulties of obtaining reliable data on wet calorific values are discussed and the use of dry calorific values and dry weight/length relationships is recommended.     

Observations on the size, dry weight and energy content of the eggs of some demersal fish species from British marine waters

The diameters, dry weights and calorific value of the eggs of seven gadoid species (cod, Gadus morhua , haddock, Melanogrammus aeglefinus , whiting, Merlangius merlangus , Norway pout, Trisopterus esmarkii , lythe. Pollachius pollachius , saithe, P. virens , ling. Molva molva ) and one pleuronectid (plaice, Pleuronectes platessa ) were measured. Ling eggs contain an oil globule; the eggs of the other species do not.
Preservation in formaldehyde solution caused a small (<4%) reduction in egg diameter but a large (15–30%) reduction in dry weight. There was no significant difference between the dry weights of unpreserved eggs weighed after (a) oven-drying at 60° C or (b) freeze-drying. Equations relating the dry weight of unpreserved eggs to unpreserved diameter and to preserved diameter are given for six species, and general equations that may apply to all North Sea gadoids whose eggs lack an oil globule are calculated. The calorific values of the dried, unpreserved eggs of all species except ling were similar (mean 23.19 kJ g⁻¹, S.D. 1.50) but the value for ling was higher (mean 26.92 kJ g⁻¹, S.D. 2.29). The estimated energy content (kJ 1000 eggs⁻¹) of eggs of each species are tabulated.     

Seasonal changes in calorific value of three pacific coast seaweeds,and their significance to some marine invertebrate herbivores

Samples of three intertidal seaweeds, Iridaea cordata (Turner) Bory, Hedophyllum sessile (C. Agardh) Setchell and Lessoniopsis littoralis (Farlow and Setchell) Reinke, collected at nine intervals over the period May 1971–May 1972, showed statistically significant seasonal fluctuations in percentage dry weight, percentage ash content, and calorific value. Percentage dry matter was generally highest in late summer through winter, whereas ash content was low. All three species showed a distinct annual cycle in calorific value of live (damp-dried) material, being highest during August–February for Hedophyllum and Iridaea, and during August–December for Lessoniopsis. Calorific values of dry material similarly varied seasonally for all species, but the differences were not significant for Iridaea. On an ash-free basis, the calorific values of Hedophyllum and Iridaea were variable during the year and only Lessoniopsis showed significantly higher values in late summer and autumn.The seasonal variability in calorific value of seaweeds has important implications in the feeding ecology of certain invertebrate herbivores. For example, while the chiton, Katherina tunicata Wood, consumed less Hedophyllum in the autumn than during the spring and summer, caloric intake did not decrease proportionately due to an inverse cycle in calorific value of Hedophyllum.In addition, we discuss for a number of invertebrate herbivores their feeding preferences, and the importance of calorific value of seaweeds and other factors which may have been involved in the evolution of these preferences.     

Nahrung und Freßverhalten bei Sedimentfressern dargestellt am Beispiel von Sipunculiden und Holothurien

Using a Phillipson microbomb calorimeter, the energy values of the “infauna-substrate-feeders”Sipunculus nudus andPhascolosoma vulgare and the nutritive value of their food substrate were determined. Calorific measurements were made of the total food substrate, of meiofauna organisms living in it and of fecal pellets from other invertebrate animals which are an important part in the food supply. Analyses of the gut content of the sipunculids and their feces were compared with the surrounding sediment. The total sediment had an ash content of about 97%, and an energy content of approximately 0.14 cal mg^?1 dry weight; this is equivalent to 165 kcal m^?2. For the meiofauna in this substrate a biomass of 800 mg dry weight was calculated. Using calorific determinations of important meiofauna groups (nematodes 5274 kcal kg^?1, ostracods 5884 and 6000 kcal kg^?1), one square meter of the sediment surface — the sipunculid food source — yielded a caloric content of 3.78 kcal for the meiofauna, which means a contribution of 2.3% to the total food substrate. The largest part of the calorific contents is by far provided by fecal pellets with 0.6 cal mg^?1 dry weight or 150 kcal m^?2; this accounts for 92% of the total calorific content of the food substrate. Peritrophic membranes and attached microorganisms may be responsible for this spectacularly high value. Coprophagy plays an important role. The rest of the total value was contributed by particulate and dissolved detritus as well as protozoans with a calculated sum of 10 kcal m^?2 or 6%. Food uptake is selective with regard to small sediment grain sizes. The amount of meiofauna in the gut is 80 times lower than in the surrounding environment, the energy content in the anterior gut 10 times higher. The energy loss inS. nudus from the anterior gut to the middle gut is more than 70%, to the posterior gut a further loss of 19% was observed. Calorific measurements in the feces were no longer possible. The utilization of food appears to be almost 100%. A correlation between ash content and the quantity of the sand grain-size fraction 37–125 μm and the calorific content is shown. The meiofauna does not represent a significant part of the total food structure, but it is taken up and utilized as food by the sediment feeding macrofauna.     

Altitudinal variation in total lipid and soluble sugar content in herbaceous plants on Mount Olympus (Greece)

Lipid and soluble sugar concentrations of leaves and stems of 168 herbaceous species, growing along an altitudinal gradient of Mount Olympus are presented. It was shown that the concentration of total lipids increased with increasing altitude, while the content of total soluble sugars decreased. The line fitting data concerning lipid and soluble sugar calorific values runs parallel to that fitting data concerning calorific content of ash free dry weight.     

Carbonisation of oil palm trunks at moderate temperatures

Thousands of tonnes of dry oil palm trunks will be produced annually in Malaysia after about 1990. A project was initiated to study the feasibility of converting palm trunks into charcoal. Carbonisation was done at terminal temperatures of 400–550°C with holding times of 1–3 h and at two heating rates. From laboratory-scale pyrolysis studies, it was found that holding time does not affect the quantity and quality of the charcoal produced, while heating rate has a minor influence. However, as terminal temperature increases, both yield and volatile content decrease while the fixed carbon content increases. The calorific value and ash contents are independent of the parameters studied and their respective values are 4032 kcal/kg and 37.2%. Since the calorific value is low and the ash content high, it is concluded that oil palm trunks are not suitable for the production of charcoal fuel.     

Analyse pondérale, élémentaire et calorimétrique des stades juvéniles de Copépodes pélagiques au cours d'une année

The change in dry weight over a year for the five copepodid states of Centropages typicus and Temora stylifera is given. The amounts of carbon and nitrogen, expressed as percentages of dry weight, are higher for copepodids than for adults. The values of the $\text{C}\text{N}$ ratios may be regarded as constant for the different stages and of the same order as those of the adults. The calorific values of young stages are higher than those of adults, because of the relatively high carbon content. A good correlation was found between the caloric value per animal (or per unit dry weight) and the dry weight of individuals.It seems that the ecological efficiency in terms of energy transport will be greater when the copepod populations are younger.     

Copper tolerance of the biomass crops Elephant grass (Pennisetum purpureum Schumach), Vetiver grass (Vetiveria zizanioides) and the upland reed (Phragmites australis) in soil culture

Pot trials were conducted to study the influence of copper (Cu) on the growth and biomass of Elephant grass (EG, Pennisetum purpureum Schumach), Vetiver grass (VG, Vetiveria zizanioides) and the upland reed (UR, Phragmites australis). Cu toxicity in EG, VG and UR was positively correlated with the total and bioavailable Cu concentrations in the soil. Based on the EC₅₀, dry weights, Cu contents, chlorophyll contents and photosynthesis rates, the Cu tolerance of the three species followed the trend EG > VG > UR. There were no significant differences in the unit calorific values among the different plants, though the total calorific values of EG were higher than those of VG and UR due to its higher biomass. The addition of KH₂PO₄ to the soil decreased the bioavailability of Cu and the Cu uptake by plants. EG could therefore be a good candidate for growth on Cu-contaminated soils, especially those improved by phosphate.     

Phenology of weight, moisture and energy reserves of Australian monarch butterflies, Danaus plexippus

Abstract. 1. In the Sydney area of New South Wales, dry weights of reproductive monarch butterflies averaged 156 mg and were higher during winter than in other seasons. Dry weights of non-reproductive monarchs ranged from 216 to 324 mg and declined by 15–25% during over wintering.
2. Fat in reproductive butterflies ranged from 0.009 to 0.017g/0.1g dry weight and was lower during winter than in other seasons. Fat content of non-reproductive monarchs was higher (0.019–0.037 g/0.1g) and declined by 24–51% during over wintering.
3. Lean dry weights of reproductive monarchs were lower than those of non-reproductive individuals. Lean dry weights of non-reproductive butterflies increased rapidly at the beginning of over wintering and remained high throughout the winter. Analysis of protein content indicated the higher lean weight of non-reproductive monarchs was due to greater protein levels.
4. Moisture content of monarchs did not vary with season or reproductive status and appeared to be correlated with ambient humidity.
5. Non-reproductive monarch butterflies in New South Wales adjust bio chemically during over wintering. Energy reserve dynamics of these butterflies are comparable to those that occur in non-reproductive monarchs in North America.     

Energy contents and organic constituents in Antarctic and south Chilean marine brown algae

The content of proteins, lipids and carbohydrates and the calorific contents in six Antarctic and three south Chilean brown algae were determined. These constitute the first reports of chemical composition in the endemic Antarctic species Cystosphaera jacquinotii, Phaeurus antarcticus and Desmarestia antarctica. There were no marked differences in total energy levels between Antarctic and cold-temperate species (values between 10.6 and 13 kJ g^–1 dry weight). However, species such as Adenocystis utricularis showed significantly higher ash-free energy (26.3 kJ), which is explained in terms of morpho-functional differentiation. Ascoseira mirabilis and Phaeurus antarcticus showed high total lipids (2.1–2.2% dry weight) and soluble carbohydrates (5.9 and 3.4% dry weight). In general, algae from Chile had similar energy levels and no obvious differences in organic content could be found.     

多变鱼腥藻在不同氮源培养条件下光能转换效率的研究

依公式PE=KY,其中K等于生物量的热值(每克干重千卡),Y等于产率即每吸收千卡光能所产生的生物量的干重,测试了在无氮和有结合氮培养下的多变鱼腥藻(Anabaena variabilis)的光能转化效率。结果指出在无氮培养下的最高PEN2为8．1％,在结合氮(NH4Cl)培养下PENH =4+为5.8％。对这种差异性作了简要讨论。     

Loss of weight in ryegrass and clover roots preserved in ethanol prior to image analysis for root traits

The dry weight content of root samples from perennial ryegrass and white clover decreased significantly over a week’s storage in 70% ethanol, but did not change further with longer storage times. Ryegrass roots lost on average 22.4% of the original dry weight, and clover roots lost 29.2%. Storage of roots in ethanol prior to image analysis of root traits could introduce significant error in the calculation of parameters involving root dry weight. Determination of root fresh weights, and dry weight for a subsample prior to preservation would allow calculation of a correction factor for dry weights obtained from preserved samples.     

Interpretation of global differences in plant calorific values

Summary Calorific values for the vegetative tissues of a group of perennial desert and arid woodland plants ranged from 3,191 to 5,375 calories per gram, oven dry weight. These span the range of comparable values reported earlier for plants in other environments, and reflect variety in adaptations to dry environments. Tissues with low values had high ash percentages, and contain significant amounts of low-energy oxalate salts. To interpret differences in calorific values for plants, one must understand: 1) the significance of calorific values in plant energetics, 2) the functions of compounds responsible for high and low values, and 3) the relative rates of metabolism and dry matter production for those plants.     

Effects of arbuscular mycorrhizal fungi on calorific value and contents of carbon and ash in Robinia pseudoacacia

该试验以根内球囊霉(Glomus intraradices)和地表球囊霉(G. versiforme)为接种剂, 研究了丛枝菌根真菌对刺槐(Robinia pseudoacacia)生物量、热值、含碳量、灰分、能量积累和碳素积累的影响。结果表明, 接种根内球囊霉和地表球囊霉对提高刺槐生物量、热值、能量积累和碳素积累都起到了重要作用。接种根内球囊霉和地表球囊霉后刺槐的总生物量比对照分别增加了89.61%和91.34%, 能量积累分别比对照增加102.20%和94.19%, 碳素积累分别比对照增加93.30%和77.21%; 同时发现刺槐的能量和碳主要分布在根系和叶, 而茎中能量和碳所占的比例较小。接种根内球囊霉提高了刺槐的干重热值, 其根、茎、叶的干重热值分别比对照增加7.72%、8.94%和8.41%; 接种地表球囊霉也显著(p < 0.05)提高了刺槐的干重热值, 但其效果低于根内球囊霉。接种根内球囊霉显著(p < 0.05)提高了刺槐根的含碳量, 对茎和叶的含碳量影响不明显。接种根内球囊霉和地表球囊霉都显著(p < 0.05)提高了刺槐茎和叶的去灰分热值。     

Yolk energy utilization in Macrobrachium nobilii (Henderson & Mathai)

Energy content of Macrobrachium nobilii (Henderson & Mathai) is 0.19 cal in a freshly laid egg, 0.14 cal in a freshly hatched zoea, and 0.09 cal in an 8-day-old non-feeding zoea. These values indicate that the yolk is utilized with an efficiency of 74%, and that yolk equivalent to 0.1 cal is provided in an egg to meet embryonic and larval metabolism. The high yolk utilization efficiency and the high calorific content of the freshly hatched zoeae (5753 cal/g dry wt) are considered as adaptations to larval migration.     

多变鱼腥藻在不同氮源培养条件下光能转换效率的研究

依公式PE=KY,其中K等于生物量的热值(每克干重千卡),Y等于产率即每吸收千卡光能所产生的生物量的干重,测试了在无氮和有结合氮培养下的多变鱼腥藻(Anabaena variabilis)的光能转化效率。结果指出在无氮培养下的最高PE_(N2)为8.1%,在结合氮(NH_4Cl)培养下PE_(NH_4~ )为5.8%。对这种差异性作了简要讨论。     

Effects of shading and of seasonal differences in weather on the growth, sugar content and sugar yield of sugar-beet crops

In 1967 and 1968 plots of sugar beet in two identically grown crops were shaded for successive four week periods starting on 13 June, 18 July and 22 August, and the growth of the plants compared with that on unshaded plots. At the beginning of each period in 1967 some shaded and unshaded plants received additional nitrogen, and in 1968 plants continuously shaded from June to September were compared with unshaded plants irrigated to equalize their water losses with those of the shaded plants. The weather in 1967 was sunny and dry and that in 1968 dull and wet, but the yields of dry matter, and particularly of sugar, of the unshaded crop in the 2 years were similar because, although net assimilation rate (E) was greater in 1967 than 1968, mean leaf area index (L) in 1968 was almost double that in the 1967 crop. Shading decreased the incoming radiation by 56%; it decreased E proportionally in 1967, increasing L slightly, but it decreased both E (by 44%) and L in 1968. The weights of dry matter and sugar in the roots of the shaded crop were consistently smaller at the end of shading and at final harvest in October in both years, and their weights, but not those of the tops or the whole plant, at final harvest over all shading treatments in both years were proportional to the amount of radiation received by the crop between June and September. Although shading greatly decreased the supply of photosynthate to the roots, it did not change the sugar content percentage of dry matter, except in the early stages of growth when the sugar content was rapidly increasing. Sugar content percentage of fresh weight of the roots was consistently decreased by shading, wholly because water content was increased relative to dry matter. Therefore the sugar yield of shaded plants was less because the dry weights of the roots were less, not because the partition of photosynthate between sugar storage and root growth changed. There appears to be a mechanism within the root operating over a wide range of photosynthate supply that maintains a nearly constant proportion of sucrose to non-sugar, contrary to the hypothesis that sugar stored in the roots is photosynthate in excess of what can be used in growth of the plant. However, in the extreme condition of continuous shading which drastically decreased the dry weights of all parts of the plant, sugar percentage of dry matter in the roots was decreased, but only from 80 to 70%. In 1967 extra nitrogen applied at the start of shading increased L and the dry weight of the tops in all periods, but had no effect on the dry weight of roots. Because 1968 was a wet year the irrigation treatment had no effect on E or L except for a slight increase in L during the first period; it had no effect on plant dry weight. Both irrigation and additional nitrogen decreased the sugar content percentage of fresh weight of the roots only by altering their water content; sugar percentage of dry matter was unaffected. None of these changes persisted until the final harvest in October.     

Biochemical and calorific content of deep-sea aspidochirotid holothurians from the northeast atlantic ocean

• 1.1. The organic composition of the body tissues of eight species of deep-sea aspidochirotid holothurian, collected between 500 and 4100m depth in the NE Atlantic Ocean, was obtained by the biochemical analysis of protein, lipid, carbohydrate and % ash.
• 2.2. The major organic class was protein with soluble lipid the major soluble fraction in the ovary. Carbohydrate values were consistently low.
• 3.3. The calorific value was significantly higher in the ovary than in the other tissues.
• 4.4. The total body calorific content for two selected species, Benthothuria funebris and Mesothuria lactea, was 25.62 and 26.24J/mg ash-free dry weight (AFDW).

     

Variations in the energy content of freshwater fish

The calorific value of the three-spined stickleback, Gasterosteus aculeatus , varied with its size, sex and the season. Fish of 16 mg dry weight had a value of 1950 cal/g while for fish of 313 mg the value was 470 cal/g. The califoric value of gravid females was 23% above that of males of comparable size. The califoric value of a tropical cichlid, Tilapia nilotica , with a dry weight of 11 g was 4300 cal/g, the calorific values of the tissues ranged from 2500 cal/g for bone to 5190 cal/g for muscle.     

Preliminary studies on the respiratory energy loss of a spider,Lycosa pseudoannulata

To elucidate the basic food requirement of spiders, the important polyphagous predators of rice-plant insect pests, an attempt was made to measure the respiratory energy loss of fasting spiders, Lycosa pseudoannulata. Relationship between fresh (y) and dry (x) weights of spiders inhabiting the bottom layer of the rice-plant community was represented by the following allometric equation:y=0.428x^0.872. The carbon dioxide production by previously fed and unfed females under the dark at 29°C 100% R. H. was measured by a titration technique. The relationship between fresh body weight and CO₂ production by unfed animals could be represented by the equation M=aW^b, M being the CO₂ output per individual per day and W the fresh body weight. The constant b, which determines the slope of curve, was 0.808. Respiration of the adult female with 100 mg fresh weight was 1.155±0.250 mg CO₂/100 g fresh weight/day or 48.69 mg CO₂/g dry weight/day. This value corresponds to 35.81 cal/g fresh weight/day or 150.94 cal/g dry weight/day. Supposing the calorific content of spiders to be 5820 cal/g dry weight, rate of the respiratory energy loss to total energy of the body was estimated to be 2.60%. This rate did not strongly contradict with the loss of fresh body weight before and after the measurement. The metabolic rate showed remarkable fluctuation with changing food supply. The CO₂ production of starved individuals decreased to 83.63±16.34% as compared with individuals which were fed before the measurement.