Strontium/Calcium ratios in statoliths of the neon flying squid, Ommastrephes bartrami (Cephalopoda), in the North Pacific Ocean

Strontium to calcium ratios were observed along longitudinal sections of statoliths of nine neon flying squid, Ommastrephes bartrami (LeSueur, 1821), including three mature females (422 to 454 mm mantle length, ML; 207 to 306 d old) obtained from the North Pacific (27–35°N; 144–150°E) during winter and six immature males and females (187 to 226 mm ML; 126 to 164 d old) collected from 39°N; 145°E and 39°N; 169°W during summer. The distances between the nucleus (core) and the edge of the dorsal dome were approximately 660 to 690 μm in mature females and 450 to 510 μm in the immature squid. Sr/Ca ratios were determined at intervals of 30 μm between the nucleus and edge of the dorsal dome. Sr/Ca ratios were higher in areas near the nuclei and peripheral portions of the dorsal dome than in the middle portions of the statoliths (270 to 420 μm from the nuclei, corresponding to ages of 60 to 90 d) in mature females; thus a U-shaped pattern was evident. Sr/Ca ratios in the six immature squid decreased from nucleus to the dorsal dome; in three squid the ratios slightly increased toward the dorsal dome edge. The observed Sr/Ca ratios in immature squid were considered to represent younger portions of the U-shaped pattern. In the present study we discuss this pattern in relation to environmental and biological conditions of O. bartrami, which undertakes seasonal migrations between spawning grounds in the Subtropical Domain and feeding grounds in the Subarctic Domain and Transitional Zone in the North Pacific Ocean. Although Sr/Ca ratios are potentially affected by ambient water temperature and ontogenetic conditions, including somatic growth and statolith growth, it was impossible to evaluate each environmental and biological effect separately, as variations in these factors are complicated and effects could be interdependent. Received: 11 April 1997 / Accepted: 27 December 1997     

Influence of temperature and salinity on the trace element incorporation into statoliths of the common cuttlefish (<Emphasis Type="Italic">Sepia officinalis</Emphasis>)

The use of statolith chemistry to trace migration pathways and distinguish populations of cephalopods is based on the assumption that the elemental composition of statoliths is influenced by physicochemical properties of the ambient environment. However, such influences have not been investigated experimentally up until now. This study presents the first microchemical analyses of cephalopod statoliths obtained from laboratory experiments under different controlled temperature and salinity conditions. Our results show that statolith chemical composition is strongly related to both salinity and temperature in ambient waters. The Ba/Ca ratio is negatively related to temperature and shows no relation to salinity. The I/Ca ratio is positively related to temperature and negatively to salinity. No Sr/Ca relation was found to either salinity or temperature, suggesting that the well-established proxy strontium is not as useful in cephalopod statoliths as in other biomineralized aragonites. Microanalysis of trace elements, however, shows an enormous potential for field studies on distribution, migration and stock separation of cephalopods. Furthermore, Synchrotron X-ray Fluorescence Analysis is introduced as a promising novel method for statolith analysis, providing a spatial resolution of typically 10–15 μm combined with detection limits down to 0.5 ppm.     

Geographic variation in statolith trace elements of the Humboldt squid, Dosidicus gigas, in high seas of Eastern Pacific Ocean

We applied the solution-based inductively coupled plasma mass spectrometry to quantify trace elements in statoliths of Humboldt squid, Dosidicus gigas, collected from the high seas off Chile, Peru, and Costa Rica by Chinese squid jigging vessels during 2007–2009. All squid samples were aged and their spawning dates were back-calculated based on daily increments in statoliths. The most abundant trace elements in the whole statolith were Ca and Sr followed by other elements in the order of Fe, Mg, Zn, Ba, Cu, Mn, Ni, Al, Cr, Co, and U. Significant differences in Mn and Sr were found among samples from the three regions. Sr, Ni, Mn, and Co contributed significantly to the discrimination among the regions, with Co responsible for explaining most of the variation, followed by Ni, Mn, and Sr. Squid from the high seas off Costa Rica could be separated from those off Peru and Chile mostly due to the differences in Ni, Sr, and Co, while samples off Peru and Chile could be distinguished mainly because of differences in Mn and Co. Discriminant function analysis suggested that the overall cross-validated classification rate was 85.6 % with samples off Chile having the highest correct identification rates and samples off Costa Rica having the highest false classification rates. Significant positive relationships were found between sea surface temperature (SST) and Cr/Ca, Mn/Ca, and U/Ca, and there was a negative relationship between SST and Cu/Ca, Sr/Ca. This study suggests that the spatial difference in trace elements of statolith can be used to separate geographic populations of D. gigas and that elements having significant relationships with SST can be considered as natural indicators of ambient temperature.     

Effect of temperature on statolith growth of the European squid Loligo vulgaris during early life

Over the past decade, statolith interpretation has resulted in a major advance in our knowledge of squid population-dynamics, but the way in which environmental conditions affect the statolith increment-deposition ratio remains virtually unknown. The object of the present study was to determine the effect of temperature on this process, using tetracycline marks to validate statolith growth in Loligo vulgaris Lamarck, 1798 under rearing conditions equivalent to severe winter (11 °C) and summer (19 °C) temperature regimes. Tetracycline marking was performed every 10 d (at 10, 20, 30, 40, 50 and 60 d of age). The newly hatched squid paralarvae were slightly smaller in summer than those hatched in winter. Survival rates were similar in both cultures, but growth rates (wet mass) of summer squids were double those in winter. At hatching, statoliths were already longer in the summer squids, and growth rates were 2% d⁻¹ as opposed to 0.9% d⁻¹ for winter statoliths. For the dorsal dome area of the statolith, where more increment counts were made, statolith growth was of 3.25 μm d⁻¹ in summer, and daily increment deposition was confirmed in 87% of the statoliths. The slow growth of statoliths at winter temperatures yielded a mean growth of 1.1 μm d⁻¹– insufficient to discern the increments using light microscopy. Subsequent SEM observation enabled only 21% of the winter statoliths to be read; these also indicated a deposition rate of one increment d⁻¹. Since the life span of L. vulgaris is ≃1 yr, squids will experience at least one winter during their life cycle, and this might be visible on the statolith. Received: 28 June 1999 / Accepted: 20 December 1999     

Differential increment-deposition rate in embryonic statoliths of the loliginid squid Loligo vulgaris

 Apart from one study that reported growth of less than one increment per day in statoliths of the squid Alloteuthis subulata, most studies so far have presumed that one increment was laid down per day in the statoliths of the squid species they examined. The present study provides evidence of differential daily growth rates in embryonic statoliths of the squid Loligo vulgaris Lamarck, 1798, thus confirming a previous report for A. subulata. Incremental growth rates of L. vulgaris statoliths differ as a function of temperature. Squid embryos were incubated in the laboratory at three temperatures (12.0, 15.5 and 21.1 °C), and tetracycline staining was used to follow statolith growth. This growth slowed in squid exposed to the lowest temperature, but recovered when the squid were returned to warm conditions, indicating statolith adaptation. Statolith growth rate after incubation at 12 °C was 1.3% d⁻¹ and reached 6.1% d⁻¹ for squids exposed to 21.1 °C. Statoliths from embryos incubated at 15.5 °C yielded a rate of 1 increment d⁻¹ and a mean daily growth of 2.2 μm in the dorsal dome area of the statolith. In contrast, the slow growth of statoliths incubated at 12 °C yielded a mean daily growth of only 0.9 μm in the dorsal dome and the readings resulted in a less-than-daily increment-deposition rate. Received: 9 October 1999 / Accepted: 30 March 2000     

Comparison of the statolith structures of <Emphasis Type="Italic">Chironex fleckeri</Emphasis> (Cnidaria,Cubozoa) and <Emphasis Type="Italic">Periphylla periphylla</Emphasis> (Cnidaria,Scyphozoa): a phylogenetic approach

The rhopalia and statocysts of Periphylla periphylla (Péron and Lesueur in Ann Mus Hist Nat Marseille 14:316–366,1809) and Chironex fleckeri Southcott (Aust J Mar Freshw Res 7(2):254–280 1956) were examined histologically and showed several homologous characteristics. Differences in sensory area distribution could be connected to a slightly different functionality of equilibrium sensing. In P. periphylla, the statoliths (crystals) grow independently of each other; whereas in C. fleckeri, one large crystal covers the smaller ones. The structures of both statoliths were examined in detail with single-crystal diffraction, microtomography and diffraction contrast tomography. The single compact statolith of C. fleckeri consisted of bassanite as was previously known only for other rhopaliophoran medusae. An origin area with several small oligocrystals was located in the centre of the cubozoan statolith. The origin areas and the accretion of statoliths are similar in both species. Our results lead to the assumption that the single bassanite statolith of C. fleckeri (Cnidaria, Cubozoa) is a progression of the scyphozoan multiplex statolith. It is therefore suggested that the Cubozoa are derived from a scyphozoan ancestor and are a highly developed taxa within the Rhopaliophora.     

Influence of temperature on the microstructure of statoliths of the thumbstall squid Lolliguncula brevis

 A laboratory study investigating the influence of temperature on the microstructure of statoliths of Lolliguncula brevis is described. Groups of squid were subjected to various temperature regimes for periods in excess of 30 d. Statoliths extracted from 20 squid were examined using a confocal microscope in laser scanning mode. The parts of the statoliths deposited during the course of the experiments were identified using either putative daily increment counts or from checks produced in response to capture and handling. These checks appear to consist of a series of prominent increments rather than reflecting a period of interrupted statolith growth. Increments deposited during the experiment generally displayed reduced contrast and clarity in comparison to the “wild” parts of the statolith, presumably in response to the constant conditions imposed in the laboratory. Average statolith growth rates observed over the course of the experiment showed a strong positive relationship to ambient temperature. A significant sex effect was apparent, with statoliths of female squid generally growing faster than those of males. Observed statolith growth rates at 15 °C were generally below 1 μm d⁻¹, suggesting that the widths of daily increments produced under these conditions may approach the resolution limits of a light microscope. The implications for studies using increment numbers to estimate age are discussed. Received: 23 July 1999 / Accepted: 17 February 2000     

The influence of ration level on growth and statolith increment width of the tropical squid Sepioteuthis lessoniana (Cephalopoda: Loliginidae): an experimental approach

Juvenile squids were grown in individual 2.6-l floating enclosures and were fed either a high- or a low-ration diet of fish and the crustacean Acetes. Squids were maintained for a maximum of 44 days in two experiments. The high-ration individuals reached a significantly larger size in both experiments (27, 25.5 mm mean mantle length, ML) compared to their low-ration siblings (19 mm mean ML) in both experiments. The statolith increment widths prior to the start of the experiment were significantly wider (between 3 and 4 μm) compared to the increment widths after the start of the experiment (between 2 and 3 μm) both for the low- and the high-ration squids. High-ration squids also had significantly wider increments and larger statoliths than their low-ration siblings. Even though we detected consistent trends in daily statolith increment widths for the different feeding regimes, we could not detect variation in increment widths at a daily level of resolution (i.e. as a result of differences in day-to-day food intake at an individual level). This was probably due to the relatively consistent diet experienced by each individual. These experiments revealed that ration level influences squid growth rate, statolith size and daily statolith increment width. Received: 30 March 2000 / Accepted: 30 October 2000     

On the potential use of magnesium and strontium concentrations as ecological indicators in the calcite skeleton of the red coral (Corallium rubrum)

 The variability of magnesium, strontium and calcium concentrations in the two skeleton types (sclerites and axis) of the red coral (Corallium rubrum) was assessed by using X-ray fluorescence spectroscopy and microprobe analysis as a prerequisite for their use as ecological indicators. Axis cross sections showed light and dark circular growth bands corresponding to fast and slow growth, respectively. Using microprobe analyses the Mg and Sr concentrations ranged from 2.8 to 3.0% and from 0.21 to 0.29%, respectively, in the sclerites and from 2.4 to 3.0% and from 0.1 to 0.28%, respectively, in the axis. Mg/Ca and Sr/Ca ratios varied within sclerites (average, 12% for both ratios) and within the axis of single colonies (average, 20% for Mg/Ca and 48% for Sr/Ca). Sr/Ca ratios in the axis were lower in fast-growing branch tips than in older, more basal parts of the colonies, whereas the Mg/Ca ratio did not differ significantly between colony regions. Mg/Ca and Sr/Ca ratios in the axis decreased significantly with depth, and we estimated an increase of the Mg/Ca ratio of 0.004–0.006 per degree Celsius. In all depth layers, Sr/Ca ratios showed a significant direct relationship with skeleton density in axis cross sections, whereas there was no significant relationship for Mg/Ca. Overall, our data indicate that temperature promotes the incorporation of Mg in C. rubrum as in other calcite skeletons, whereas Sr concentrations are inversely related to growth rate. This preliminary study suggests that Mg and Sr concentrations in the axis of the red coral have a strong potential as ecological indicator for temperature and growth rate. Received: 3 March 2000 / Accepted: 30 August 2000     

Nutritionally relevant elements in staple foods: influence of arable site versus choice of variety

Eighteen representative sites for the Austrian grain-growing and eight for the potato-growing zones (soils and crops) were investigated. On each site, total element contents (B, Ba, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Mo, Na, P, Sr and Zn) were determined in 4–12 varieties of winter wheat (n = 136), 6 varieties of spring durum wheat (n = 30), 5 varieties of winter durum wheat (n = 15), 7 varieties of rye (n = 49), 5 varieties of spring barley (n = 30) and 5 varieties of potatoes (n = 40). Element accumulations in grain species and potato tubers varied significantly with site conditions, with the main exceptions for B in potatoes and wheat as well as for Zn, Cu and Co in durum wheat. On average, across all investigated sites, differences in varieties occurred concerning the elements Ca, Cd, Ba, Sr and Zn (except Zn in potatoes and winter durum). A rough estimation revealed that an average Austrian consumer of wheat, rye and potatoes meets more than 50% of the needs of daily element intake for K, P and Mg, between 36 and 72% for Fe, Zn and Cu, and more than 100% for Co, Mo and Mn. In particular, the elements Ca and Na have to be added from other sources.     

The gastropod statolith: a tool for determining the age of<Emphasis Type="Italic"> Nassarius reticulatus</Emphasis>

The microstructure, shape and appearance of the growth rings in statoliths of Nassarius reticulatus (L.) were investigated. This species possesses two statocysts, each containing a single spherical statolith of calcium carbonate of up to 0.22 mm in diameter in the largest animals. The relationship between statolith diameter (SD) and total shell height (TSH) is exponential [ln(TSH)=26.3SD–0.842], although the function is site specific. Statoliths of the largest whelks (>29 mm) contained three or four clearly defined rings, corresponding to TSH values of ~1.1, 4.6–5.3, 12.0–13.5 and 18.5 mm, respectively. The first ring likely represents the metamorphic ring that was deposited at the time of larval metamorphosis when the post-larval whelk adopted a benthic lifestyle. The estimated size of the whelks at formation of the second, third and fourth statolith rings closely matched the TSH inferred from the shell rings. It is concluded that the patterns of growth rings present in statoliths can provide information about the age and growth of N. reticulatus.Communicated by O. Kinne, Oldendorf/Luhe     

Bioelements and mineral matter in human livers from the highly industrialized region of the Upper Silesia Coal Basin (Poland)

Contents of mineral substance, silica, and a range of bioelements and toxic elements (Mg, Na, K, Ca, Ba, Zn, Cr, P Al, Cd, Mn Cu, Ni, Pb, Sr, Fe) in 38 livers of donors from the Upper Silesia Coal Basin (southern Poland) are presented. Elements were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) with the exception of silica that was estimated colorimetrically. Concentrations, concentration variability, and correlations between selected liver components determined for the total population are related to donor age, gender, and lesion occurrence. Correlations between particular elements were found using correlation coefficient values and the Fisher transformation. Mineral substance in the livers lies in the range 0.40–5.03 wt%. With increasing donor age, mineral-matter content decreases to a minimum for the 40–60 years of age range. Microbioelement contents show a similar tendency, while microbioelements and toxic elements reach maximum contents in donors aged 60–80 years. All elements show content decreases in livers from the oldest group (>80 years). Silica contents increase with age. Variability of element contents is lowest in the older subpopulations. Livers with lesions show lower element contents and variability. The results are compared to literature data for regions of Poland assumed to be of low pollution and to data from comparable regions in Japan and Hungary. Up to our knowledge, this paper is the first work describing the total contents, as distinct from contents of selected elements, of mineral substance in human livers.     

An experimental study of the effect of diet on the fatty acid profiles of the European Cuttlefish (<Emphasis Type="Italic">Sepia officinalis</Emphasis>)

Fatty acid analysis is an alternative dietary investigation tool that complements the more traditional techniques of stomach content and faecal analysis that are often subject to a wide range of biases. In applying fatty acid analysis to ecosystem studies, it is important to have an understanding of the effect diet has on the fatty acid profile of the predator. A feeding experiment, using crustacean and fish as prey for the European cuttlefish Sepia officinalis, was conducted to evaluate the effect of prey fatty acids on the fatty acid profile of this marine predator. Cuttlefish were fed on a fish diet for the first 29 days, and then changed to a crustacean diet for a further 28 days. Another group of cuttlefish was fed on a crustacean diet for the first 29 days, and then changed to a fish diet for a further 28 days. An analysis of the cuttlefish digestive gland showed that the fatty acid profile reflected that of the prey, with cuttlefish on a crustacean diet being clearly distinguishable from the cuttlefish on a fish diet. Cuttlefish fed on a fish diet for 29 days prior to the switch in diet were comparatively higher in 16:0, AA, 20:1ω9, DPA6, DHA, 22:4ω6 and DPA3 than those fed on crustaceans. Cuttlefish fed on a crustacean diet for 29 days prior to the switch in diet were comparatively higher in 17:1ω8, 18:1ω9, 18:2ω6, 18:1ω7, EPA and 20:2ω6 than those fed on fish. Following a change in diet, the fatty acid profile of the cuttlefish digestive gland reflected that of the new diet within 14 days. The results confirm that the fatty acid profile of the cuttlefish digestive gland clearly reflects the profile of its recent diet. It also shows that the digestive gland may not be an organ that accumulates dietary lipids for long-term storage, but rather is an organ where lipids are rapidly being turned over and potentially excreted.     

Elemental composition of a tusk of a dugong, Dugong dugon, from Exmouth, Western Australia

Element analysis of the annual increments in a longitudinal section from the tusk of a female dugong Dugong dugon (Müller) from Exmouth, Western Australia, was carried out by X-ray fluorescence-imaging, inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectrometry (ICP-MS). Nine elements (Ba, Ca, Fe, Li, Mg, Na, P, Sr and Zn) were present in concentrations amenable to determination by these techniques. Most elements revealed both long-term trends and shorter, year-to-year, variations. For example, sodium concentrations increased from 0.55 to 0.72% with the age of the dugong. Strontium concentrations (mean 0.17%) were closely correlated (r = 0.86) with those of barium (mean 4.5 mg kg⁻¹). Zinc concentrations increased from ∼70 to 170 mg kg⁻¹ with dugong age, but also showed shorter-term fluctuations of ∼30 mg kg⁻¹ that were correlated (r = 0.41) with mean annual Fremantle sea level (a measure of the Southern Oscillation Index and strength of the Leeuwin Current). The concentrations of the elements and correlations with year and between pairs of elements are discussed. Received: 10 January 1997 / Accepted: 21 April 1997     

A Numerical Study for Turbulent Flow and Thermal Influence over Inhomogenous Canopy of Roughness Elements

A large-eddy simulation with transitional structure function(TSF) subgrid model we previously proposed was performed to investigate the turbulent flow with thermal influence over an inhomogeneous canopy, which was represented as alternative large and small roughness elements. The aerodynamic and thermodynamic effects of the presence of a layer of large roughness elements were modelled by adding a drag term to the three-dimensional Navier–Stokes equations and a heat source/sink term to the scalar equation, respectively. The layer of small roughness elements was simply treated using the method as described in paper (Moeng 1984, J. Atmos Sci. 41, 2052–2062) for homogeneous rough surface. The horizontally averaged statistics such as mean vertical profiles of wind velocity, air temperature, et al., are in reasonable agreement with Gao et al.(1989, Boundary layer meteorol. 47, 349–377) field observation (homogeneous canopy). Not surprisingly, the calculated instantaneous velocity and temperature fields show that the roughness elements considerably changed the turbulent structure within the canopy. The adjustment of the mean vertical profiles of velocity and temperature was studied, which was found qualitatively comparable with Belcher et al. (2003, J Fluid Mech. 488, 369–398)’s theoretical results. The urban heat island(UHI) was investigated imposing heat source in the region of large roughness elements. An elevated inversion layer, a phenomenon often observed in the urban area (Sang et al., J Wind Eng. Ind. Aesodyn. 87, 243–258)’s was successfully simulated above the canopy. The cool island(CI) was also investigated imposing heat sink to simply model the evaporation of plant canopy. An inversion layer was found very stable and robust within the canopy.     

The trophic link between squid and the emperor penguin <Emphasis Type="Italic">Aptenodytes forsteri</Emphasis> at Pointe Géologie,Antarctica

Cephalopod beaks retrieved from stomachs of dead emperor penguin chicks at Pointe Géologie, Terre Adélie, provide information on taxonomic and size composition of the penguin’s squid diet, on the trophic range of the squid species preyed upon and on the fractional trophic impact of the penguin on the whole food web. Emperor penguins prey upon four squid species (Psychroteuthis glacialis, Kondakovia longimana, Gonatus antarcticus, Alluroteuthis antarcticus) and do not take squid larger than 480 mm mantle length. Larger squid live either below the penguin’s diving range or are beyond its handling capacity. Nitrogen stable isotope ratios indicate that squids cover a range of about two trophic levels (2.5–8‰ δ¹⁵N). The impact of the emperor penguin, however, concentrates on the upper part of this range, about 68% of its squid prey being >6‰ δ¹⁵N. The principal components of the emperor’s diet, fish, krill and squid, differ distinctly in average trophic level. Consequently the trophic position of the emperor penguin changes accordingly with diet composition and may differ by almost one trophic level between different emperor penguin colonies.     

Age and growth of the naticid gastropod <Emphasis Type="Italic">Polinices pulchellus</Emphasis> (Gastropoda: Naticidae) based on length frequency analysis and statolith growth rings

In Red Wharf Bay, UK the naticid gastropod, Polinices pulchellus, was more abundant and more highly aggregated during the summer months (June–August 2001) than during the winter (December 2000). Whilst small numbers of juvenile P. pulchellus (4–6 mm shell length) were present throughout the year the population consisted mainly of individuals of 12–14 mm shell length. Juvenile snails grew rapidly in size during the winter and early spring; growth then virtually ceased between May and June, following which there was a further period of rapid growth between August and February. Densities ranged between 57 and 4,073 ha⁻¹ and the largest individual collected during this investigation measured 16.2 mm in shell length. Statoliths from adult P. pulchellus revealed the presence of a settlement ring and two prominent growth rings (rings 1 and 2). A curvilinear relationship exists between statolith diameter and shell length in snails up to 16 mm in length. Settlement rings ranged in diameter from 19.7 to 45.2 μm (mean 29.8 μm; SE=0.41) giving an estimated shell length of the settled juvenile of 1.1 mm. The diameter of ring 1 and ring 2 were significantly correlated indicating that rapid growth during the first year is maintained during year 2. Shell lengths estimated from the diameters of the prominent statolith rings and those obtained from length frequency data analysis (LFDA), were broadly congruent strongly suggesting an annual periodicity to the statolith rings. The largest snails (>15 mm) present within this population were estimated to be between 2 and 3 years old. Von Bertallanfy seasonal growth curves obtained from the LFDA predicted values of L∞, K and t ₀ of 14.32 mm, 1.54 and −0.14 years, respectively, suggesting that P. pulchellus rapidly attains its maximum asymptotic size.     

The effect of ration size, temperature and body weight on specific dynamic action of the common cuttlefish Sepia officinalis

The effect of meal size (shrimp Crangon crangon) [0.83–18.82% dry body weight (Dw)] on specific dynamic action (SDA) was assessed in cuttlefish Sepia officinalis (1.03–6.25 g Dw) held at 15 and 20°C. Cuttlefish <2 g significantly expended less energy in feeding and digesting their meal than cuttlefish >2 g when given the same quantity of food. Handling, eating and digesting a shrimp meal was temperature dependent with cuttlefish processing and digesting a similar sized shrimp meal faster at 20°C than at 15°C. The proportional increase in oxygen consumption (2.07 ± 0.02) was not correlated with feeding rate (FR) and was independent of temperature and cuttlefish size. The SDA peak was not correlated with FRs, and increased as cuttlefish size and temperature increased. The mean SDA coefficient was 0.87 ± 0.07% of the ingested energy; one of the lowest SDA values recorded amongst vertebrates and invertebrates. Daily energy requirements (KJ day⁻¹) for S. officinalis were calculated from laboratory estimates of energy losses due to standard (MO_{2 Standard}), routine (MO_{2 Routine}) and feeding (MO_{2 SDA}) oxygen consumption. Laboratory estimates of daily metabolic expenditures were combined with results from previous investigations to construct an energy budget for 1 and 5 g cuttlefish consuming a meal of 5 and 15% Dw at 20°C and the amount of energy available for growth was estimated to be between 35 and 80.3% of the ingested energy.     

Effects of calcium,strontium, and magnesium on the coccolithophorid Cricosphaera (Hymenomonas) carterae. I. Calcification

The present investigation concerns the effects of calcium, strontium, and magnesium on calcification and mineralogy of the calcified bodies (coccoliths) of the coccolithophorid Cricosphaera (Hymenomonas) carterae. The capacity of cells to calcify in various concentrations of these ions was examined following preliminary decalcification in CO₂. At a concentration of 10^-2 M Ca, 75% of the cells formed coccoliths within 24 h and almost all cells were recalcified after 2 days. At 10^-3 or 10^-4 M Ca no recalcification occurred. However, with the addition of Sr to the Ca-deficient media, calcification took place as shown by observations of coccoliths and by analysis of Ca. The percentage of calcified cells increased with increasing concentrations of Sr. Strontium added to a Ca-deficient media was much more effective than an equivalent concentration of Ca. No Sr was deposited in the coccoliths. X-ray analysis demonstrated that calcite was deposited by cells in all concentrations of Ca and Sr at which calcification took place. At concentrations of Mg in the media from O. O to 4.2×10^-2 M, the cells retained their ability to calcify, although calcification was markedly reduced in the absence of Mg. In low Mg concentrations (1.3×10^-4 and 4.2×10^-6 M), the coccoliths were 60% calcite and 40% aragonite, and in teh absence of Mg, only calcite was formed.     

Detection of elements and radioactivity in pellets from long-eared owls (Asio otus) inhabiting the city of Belgrade (Serbia)

In this study, we analysed pellets from long-eared owls (Asio otus) collected from four localities in Belgrade (Serbia). The pellets contained the remains of prey, namely voles (Arvicola terrestris) and field mice (Apodemus agrarius). The concentrations of 14 elements (Ca, P, Mg, Na, K, Fe, Zn, Sr, Ba, Mn, Ti, Cu, Si, B) were evaluated in whole pellets and in samples containing only bone tissue, which were dissected from the whole pellet. The increased levels of certain elements, including Mn, Zn, Ba, Cu and radioactive ⁴⁰K, indicate contamination of the soil by various sources, such as industrial plants and agricultural practices. From the results presented in this article, we suggest that the analysis of owl pellets may indicate the quality of the local environment.