Shell Volume Research Articles

Amelioration of different acidic soils in China using seafood shell biochars.

Soil acidification limits crop and pasture production and leads to the degradation of agroecosystems. A substantial volume of seafood shells are discarded each year, which creates enormous environmental and social pressures. In this study, the anaerobic pyrolysis characteristics of four types of seafood shells (clam, scallop, oyster, and mussel) were evaluated. Then, outdoor pot experiments using canola (Brassica napus L.) were conducted and the soil solution was collected in situ to determine the pH, organic matter, nutrient content, and aluminum (Al) species in soil liquid and solid phase. Finally, the relationships between the growth of canola and the concentration of phytotoxic Al were investigated to evaluate the amelioration efficacy and mechanism of seafood shell biochars applied to three typical acidic soils in China. The results showed that seafood shell biochars pyrolyzed under 800°C anaerobic conditions had characteristics of inorganic and organic amendments. The addition of 2gkg-1 four seafood shell biochars pyrolyzed at 800°C could increase pH of three kinds of severely acidified soils and soil solutions to more than 5.0, and adding 4gkg-1 could increase they to more than 6.0. After adding 4gkg-1 four seafood shell biochars in Oxisol-GD, Ultisol-AH and Ultisol-JX, the Al concentration of soil solution decreased by more than 89%, 88% and 80%, respectively; the effects were similar to lime. The application of four seafood shell biochars promoted the transformation of water-soluble Al and exchangeable Al in acidic soils into organically bound Al, adsorbed hydroxyl Al, and more stable Al, thus greatly reducing the concentration of Al in soil solution; this improved the growth of canola and increased the yield.

Effect of shell composition on watertightness and mechanical performance of cement-based capsules used as self-healing additives of cement

The aim of this work is the development of cementitious macro-capsules for self-healing cement and concrete materials. Emphasis is placed on shell properties, including size, thickness, strength, and volume to active component ratio. This enhancement is aimed at protecting the healing agent and ensuring adequate reactivity upon crack formation, surpassing survivability considerations. To this direction, core/shell particles have been produced following the pan-coating method, while different types and concentrations of setting acceleration solutions for the shell stabilization were studied. The formation of core-shell capsules encompasses the formation a spherical core through agglomeration, followed by simultaneous spraying of cement powder and a setting acceleration solution for the shell formation, under continuous rotation. The microstructural characteristics of the shell were studied through scanning electron microscopy (SEM), while the reactivity of the protected core (reactive agent) inside the hardened mortar mixtures was evaluated using thermogravimetric analysis (TGA). Moreover, the crushing load of the capsules under compression and their survivability during mixing process were examined and interpreted in relation to their diameter, circularity, and shell thickness.The results revealed the ability of the encapsulation methodology proposed to tailor the shell properties and modify the capsule properties so as satisfy the requirements of different applications. The use of setting accelerators during shell formation proved essential for enhancing the density and the strength of the shell layer. As a consequence, this leads to macro-scale capsules with elevated survivability rate and core reactivity.

Micro container made of levitated liquid bead

Liquid bead, an emerging digital microfluidic platform offers a wide range of applications in research and industry. Making liquid beads using acoustic levitation technology allows for the fabrication of micro container. Extensive insight into levitated liquid beads is essential for determining their performance. Firstly, this paper unfolds the unique interface of the levitated liquid bead, which has thin membrane of shell material on top and thus serves as a micro container. Next, we characterised the puncture toughness of liquid beads to assess the capability of releasing the liquid content. Liquid bead with larger corresponding shell volume and lower core volume recorded the highest resistance against needle penetration. Finally, we observed the thermal behaviour of liquid beads at elevated temperature. The liquid beads showed no morphological change over 10-minutes period at 50 °C. At 65 °C, liquid bead exceeded the critical temperature threshold, which resulted in breaking the thin membrane and releasing the liquid from the core.

Genotype and dietary supplementation of ginger (Zingibar officinale) rhizome powder affect egg quality traits of layer chickens

This study evaluated the effects of ginger (Z. officinale) rhizome powder on egg qualities of aged commercial and native hens using 160 Shaver Brown (SB) and Nigerian heavy ecotype native hens (HEN). Experimental groups per genotype were control group or basal diet group, and ginger rhizome powder supplemented group (20 g/kg, ginger group). For each genotype, forty (40) hens were assigned to the control group and 120 hens to the ginger group. Each experimental group had four (4) replicates containing 10 hens each for the control groups, and 30 hens each for the ginger groups. The hens were housed individually in laying cages and fed the experimental diets at 125 g/bird/day. Water was given ad libitum and photoperiod was 12 h light and darkness. 80 eggs from SB and 40 eggs from HEN control groups, and 80 eggs/genotype from the ginger groups were used to evaluate egg qualities while 10 shell samples were used to evaluate shell mineral contents for each group. In addition, within genotypes, eggs belonging to the ginger groups were grouped into egg weight and egg shape index grades and assessed for egg qualities. SB eggs had significantly (p ≤ 0.05) higher weight (EW), length (EL), diameter (ED), surface area (ESA), volume (EV), and shape index (ESI); yolk, albumen, and shell weights (YW, AW and SW); albumen height, diameter, and ratio (AH, AD, and AR); shell volume (SV), compression fracture force (SCFF), and calcium content but lower egg specific gravity (ESG), yolk ratio (YR), yolk/albumen ratio (Y/A ratio), shell Zinc, and Phosphorus contents compared to HEN eggs. Ginger groups had higher EW, EL, ESA, EV, YW, YD, YR, AH, AI, Y/A ratio, and shell Zn but lower ESG, YH and YI compared to control groups. SB-ginger group had highest (p ≤ 0.000) AD while HEN-ginger group had highest (p ≤ 0.05) shell Zinc, and Phosphorus contents. EW grades differed significantly in EW, ESA, ESG, ESI and SCFF in the two genotypes while ESI grades differed significantly in ESI and Y/A ratio in SB but in ESI, YI and Haugh unit in HEN. In conclusion, genotype, diet, genotype x diet, EW and ESI grades influenced egg quality traits. These factors are important for egg quality evaluation and genetic improvement.

Habitat Provision Differs Across Subtidal Reefs Varying in Location Within the Estuarine Landscape

Although position within the estuarine landscape is known to influence structural characteristics and ecological functioning of many habitats, the influence of position on subtidal oyster reef characteristics and functioning is relatively understudied. This study assessed habitat provision by oysters and benthic macrofauna on subtidal bar and patch oyster reefs within the northwestern Gulf of Mexico estuary. Bar reefs had greater and more variable oyster density, biomass, and volume, as well as dead shell material, compared to patch reefs. Benthic macrofaunal community composition differed between reef types, with bar reefs hosting 11× and 30× higher biomass of Porcellanidae and Ampithoidae crustaceans, and patch reefs supporting 34× and 47× higher biomass of Eunicidae annelids and Leptocheliidae crustaceans. The environmental variables most highly correlated with macrofaunal communities on both bar and patch reefs were sediment chlorophyll-a, volume of dead oyster shells, and depth. Despite differences in structural characteristics and position within the estuarine landscape, subtidal oyster reefs are often managed as a single habitat type. Our findings emphasize the importance of considering location in oyster reef conservation and restoration efforts to better predict and optimize faunal provision outcomes.

44‐2: Towards 10‐Watt Radiant Flux——Applications and Challenges of Photoluminescent Quantum Rods in High‐Power LEDs

This report examines the thermal stability of luminescent quantum rods under high optical flux LED conditions, analyzing degradation mechanisms and key factors. Findings reveal that smaller shell volumes and effective thermal management enhance reliability and practicality in high‐power LED applications.

Gigantic gastropods from the Middle Triassic Qingyan biota of Guizhou

Body sizes of organisms underpin their ecological functions and evolutionary trajectories. Previous studies have shown that significant reduction in body size — the Lilliput effect — occurred in the aftermath of the Permian–Triassic mass extinction (PTME) and that body size did not rebound until to the late Middle Triassic (Ladinian). Here we describe three new gastropod specimens, identified as Toxoconcha sp., with unprecedented large shell sizes among Triassic gastropods, from the Qingyan biota of Guizhou, China. Meanwhile, a new dataset on the gastropod size of Lopingian (Late Permian) to Middle Triassic is presented. The largest specimen we found is ∼350 mm in height while its shell volume is estimated to be 1358661 (= 6.13 log10) mm3. As the largest record of the Triassic gastropod shells, these new fossils from Qingyan suggest that gastropod body size rebounded from the post-PTME Lilliput effect as early as the Anisian. Rapid gigantism has been reported in Middle Triassic marine reptiles, and the occurrence of giant gastropods in Qingyan suggests a convergent morphological response to the unique ecological and environmental conditions of the Middle Triassic.

Enhancing thermal performance in shell-and-tube latent heat thermal energy storage units: An experimental and numerical study of shell geometry effects

This study investigates the influence of shell geometry on the thermal performance of latent heat storage (LHS) units. Three transparent shell-and-tube LHS units, featuring circular, horizontal, and vertical obround shell geometries, each possessing a similar shell volume, were fabricated and filled with paraffin as the phase change material (PCM). Employing a combination of visualization experiments and numerical simulations, the thermal performance of LHS units with horizontally and vertically oriented obround shell geometries was comprehensively analyzed and compared with conventional circular shell-and-tube heat exchangers (HX), commonly utilized in the industry. Data derived from image processing of photographs, coupled with recorded temperatures, were used to calculate liquid fractions, analyze heat transfer characteristics, and ascertain the dominant heat transfer mechanisms during the melting process. The results reveal that the utilization of a horizontal obround shell enhances the heat transfer rate, thereby expediting the melting process. A comparative analysis of melting photographs demonstrates that the horizontal obround shell reduces the melting time by 32% compared to the circular shell, while the vertical obround shell extends the total melting time by 13%. In contrast to the circular shell, the horizontal obround shell exhibits a substantial improvement of 41% in the time-averaged heat transfer rate, whereas the vertical obround shell shows a decrease of 12%.

Many roads to success: alternative routes to building an economic shell in land snails.

Land snails exhibit an extraordinary variety of shell shapes. The way shells are constructed underlies biological and mechanical constraints that vary across gastropod clades. Here, we quantify shell geometry of the two largest groups, Stylommatophora and Cyclophoroidea, to assess the potential causes for variation in shell shape and its relative frequency. Based on micro-computed tomography scans, we estimate material efficiency through 2D and 3D generalizations of the isoperimetric ratio, quantifying the ratios between area and perimeter of whorl cross-sections (2D) and shell volume and surface (3D), respectively. We find that stylommatophorans optimize material usage through whorl overlap, which may have promoted the diversification of flat-shelled species. Cyclophoroids are bound to a circular cross-section because of their operculum; flat shells are comparatively rare. Both groups show similar solutions for tall shells, where local geometry has a smaller effect because of the double overlap between previous and current whorls. Our results suggest that material efficiency is a driving factor in the selection of shell geometry. Essentially, the evolutionary success of Stylommatophora likely roots in their higher flexibility to produce an economic shell.

On the thermodynamic entropy in the microcanonical ensemble of classical systems

We demonstrate that the surface entropy given by the volume of an energy shell in the phase space can be the thermodynamically consistent entropy in a classical microcanonical ensemble if the thickness of the energy shell is not an arbitrary constant but a non-extensive function satisfying a specific differential equation. A particular form of the energy shell thickness as a possible solution to the differential equation converts the surface entropy into the volume entropy given by the phase-space volume bounded by a constant energy surface. However, such a form bears a problem: The temperature derived accordingly becomes extensive when the density of states is a non-monotonic function of energy. Based on the adiabatic invariance of the degeneracy of a quantum system and the Weyl correspondence, we propose an alternative solution: the energy shell thickness given by the energy level spacing in the quantum counterpart of the classical ensemble considered, which is illustrated by a few simple examples.

Thermally enhanced nanocomposite phase change material slurry for solar-thermal energy storage

This paper investigates the photothermal conversion performance of an innovative heat transfer fluid containing nano-encapsulated phase change material (PCM) with metallic shell materials in a solar thermal energy storage system. The influences of shell thickness, core size, shell material type, PCM mass and shell volume concentrations on the thermal performance of the heat storage medium are investigated and compared. The results show that the heat transfer rates of water-based Ag, Au, Cu and Al nanofluids are 6.89, 5.86, 7.05 and 6.99 W, respectively, while slurries formed by adding paraffin@Ag, Au, Cu and Al nano capsules to pure water enhance heat transfer by 6.18, 13.38, 10.8 and 11.33 %, respectively. The metallic nanoparticle-based shell materials further augment the temperature and energy storage gains by enhancing the solar radiation capture capability of the heat storage medium. Specifically, depending on the mass concentration of PCM, the storage capacity of paraffin@Cu slurry is augmented by up to 290 %. As the shell thickness of the Ag particles also decreases from 8 to 2 nm, it augments the slurry's storage ability for thermal energy by 7 %. The enhancement in the dimensions of the nano capsules, however, causes the surface area-to-volume ratio (SA:V) to reduce the photothermal conversion of the slurry by clustering. Therefore, the thermal energy storage behaviour of the Paraffin@Cu slurry is diminished by 5 % as the core size enhances from 10 to 40 nm. Further, the augmentation in the volume concentration of Al particles in the shell surprisingly reduces the thermal energy storage by 5 %. Finally, paraffin-based solid PCM is also experimentally tested for validation of the specific heat capacity model at various wind speeds and solar radiation.

Доопытная оценка влияния угла атаки рабочего органа бороны-мотыги на эффективность воздействия на почву

Soil hoeing is an effective and universal technique included in almost all modern crop production technologies. Improving the harrow-hoes is quite labor-intensive, long-term and costly, which indicates the prospects for modernization based on knowledge of the operating patterns of the units under consideration. The research goal is a pre-experimental study of the influence of the approach angle of the needle-type working 20 ТеХНИКА И ТХНОЛОГИИ АПК Агроинженерия. 2024. Т. 26, № 6. С. 19-27 Несмиян А.Ю., Арженовский А.Г., Горенков М.Ю. Доопытная оценка влияния угла атаки рабочего органа… element on the intensity of its impact on the soil. The article presents a methodology to calculate the complex factor of soil crumbling depending on the approach angle of working elements at values of 0, 8, 16, 24, and 32 degrees. Based on the calculations carried out the authors assumed that under average initial operating conditions of harrow-hoes, an increase in the approach angle of the working elements leads to an increase in the total trace of the needle movement in the soil with an average intensity of about 0.6 cm3 /deg. In the meanwhile, the sheared soil shell volume per needle first increases by 1.1 to 2.3 cm3 /deg., as the approach angle reaches 24 deg., and then decreases with further increase in the angle. In general, an increase in the approach angle leads to a decrease in the complex criterion of soil crumbling by a needle at a speed of about 0.1 deg. –1. At the same time, the overall intensity of the impact on the soil increases to an approximate value of about 24 deg. as the approach angle goes on increasing. The proposed calculation method is approximate in nature, but its application helps identify some general patterns in the influence of the parameters of the disk’s working element on the performance indicators. They include afrontality, the diameter of needles, the depth of their penetration into the soil, the working element diameter, the unit speed, etc.

Serbest Sistemde Yetiştirilen Lohmann Sandy Tavuklarında Yumurta Kalite Özelliklerinin Belirlenmesi

Objective: In this study, it was aimed to determine the egg quality traits of hens belonging to Lohmann Sandy genotype raised in the free-range system.
 Materials and methods: In the research, eggs obtained from hens belonging to Lohmann Sandy genotype raised in a private enterprise in Ordu province were used. In each period for egg quality determination, 30 daily eggs were used. After keeping the eggs at room temperature for 24 hours, the internal and external quality traits of eggs were determined.
 Results: The albumen index and the Haugh unit values showed a significant change depending on time and were determined as 11.31 and 92.90 on average, respectively. On the other hand, the yolk index value did not show a significant change depending on the time and the average value was found to be 51.21. Egg weight showed a significant change depending on the time and was determined as 58.84 g on average. Shell surface area and egg volume also showed a significant change depending on time and were calculated as 74.58 cm2 and 54.41 cm3 on average, respectively. Shell thickness, shape index and specific gravity values did not show a significant change depending on time.
 Conclusion: It is of great importance that eggs produced with alternative systems are introduced to the market. In order to increase the consumption level of eggs, the place and importance of eggs in adequate and balanced nutrition should be explained, especially targeting children in developmental age and the elderly.

Magneto-thermo-elastic coupled free vibration and nonlinear frequency analytical solutions of FGM cylindrical shell

The magneto-thermo-elastic coupled free vibration of functionally graded materials (FGM) cylindrical shell is investigated. Based on the physical neutral surface theory and Kirchhoff-Love theory, the expressions of internal force and internal torque are obtained by considering the constitutive relationship that includes thermal stress. According to the electromagnetic elasticity theory, the model of Lorentz forces of the shell in magnetic field are derived. The expressions of potential energy, kinetic energy and its variational operators are given by introducing geometric nonlinearity, respectively. Based on Hamilton principle, the magneto-thermal-elastic coupled vibration equation of FGM cylindrical shell in multi-physical field is established. The displacement functions under simply supported boundary conditions are solved, which are combined with Galerkin method for derivation of nonlinear ordinary differential equations. The second-order approximate analytical solution of natural frequency is obtained by applying the multi-scale method. The characteristic curves of natural frequency with different parameters are drawn through numerical examples. The results show that reducing the volume fraction index and increasing the initial amplitude can lead to the increase of the natural frequency under transient conditions. With the increase of temperature and magnetic induction intensity, the natural frequency decreases. In addition, the natural frequency is also influenced by the shell size and volume fraction index.

Variable Salinity and Hydrogen Production in Europa's Ocean

AbstractEuropa's long‐term habitability depends on thermodynamics—modulated by tidal evolution—and geochemical pathways that define chemical and energy inventories for use by putative biology. Hydrogen produced from the reaction of water and rock during serpentinization is one potential source of metabolic energy. Here, we demonstrate how thermally modulated volumetric changes to Europa's ice shell, ocean, and fluid‐accessible rocky mantle influence oceanic salinity and serpentinization rates in Europa's interior. During periods of steady cooling, hydrogen flux into the ocean remains relatively constant because of the continuous propagation of thermal cracking into the rocky mantle regardless of ocean composition. However, during periods of fluctuating heat production driven by changes in orbital eccentricity, modulation of the ice shell volume, and consequently the salinity and water activity of the ocean, alters the serpentinization rate. In parallel, the extent of fracturing within the seafloor varies, changing the volume of reactable rock available. Our results show that the stability of serpentinization reactions on Europa over time highly depends on the thermal‐orbital evolution and oceanic salt content. The variability in the hydrogen production rate is significant across potential orbital histories, varying by up to 15 orders of magnitude for the lowest salinity and most kosmotropic ocean conditions, such as dilute MgSO4 compositions. We also show that this variability decreases with increasing ocean salinity and more chaotropic compositions, such as a concentrated NaCl ocean. These results suggest new ways that ocean composition and water activity are essential to stable habitable conditions in ocean worlds.

Geochemical Differences Between Alive, Uncrusted and Dead, Crusted Shells of Neogloboquadrina pachyderma: Implications for Paleoreconstruction

AbstractPlanktic foraminiferal‐based trace element‐calcium ratios (TE/Ca) are a cornerstone in paleoceanographic reconstructions. While TE‐environment calibrations are often established through culturing experiments, shell growth in culture is not always consistent with growth in a natural setting. For example, many species of planktic foraminifera thicken their shell at the end of their life cycle, producing a distinct “gametogenic” crust. Crust is common in fossil foraminifers, however, shells grown in culture do not often develop a thick crust. Here, we investigate potential vital effects associated with the crusting process by comparing the trace element (Mg/Ca, Na/Ca, Ba/Ca, Sr/Ca, Mn/Ca, Zn/Ca) and stable isotope (δ13C, δ18O) composition of alive, fully mature, uncrusted shells to recently deceased, crusted shells of Neogloboquadrina pachyderma collected from the same plankton tows off the Oregon (USA) coast. We find that uncrusted (N = 55) shells yield significantly higher Ba/Ca, Na/Ca, Mn/Ca, and Sr/Ca than crusted (N = 66) shells, and crust calcite records significantly lower TE/Ca values for all elements examined. Isotopic mixing models suggest that the crust calcite accounts for ∼40%–70% of crusted shell volume. Comparison of foraminiferal and seawater isotopes indicate that N. pachyderma lives in the upper 90 m of the water column, and that crust formation occurs slightly deeper than their average living depth habitat. Results highlight the necessity to establish calibrations from crusted shells, as application of calibrations from TE‐enriched uncrusted shells may yield attenuated or misleading paleoceanographic reconstructions.

A simulation-based insight into the interrelationships between density and other physical parameters of the egg

A bird's egg has a variety of distinct physical characteristics that assure its functionality as a naturally engineered ‘packaging’ for the growing embryo. It also contains essential nutrients for human food. Egg density (D) is one such crucial physical parameter frequently involved in studies pertaining to its interrelationship with the quality of both table and hatching eggs. In this investigation, we conducted more in-depth experiments based on theoretical research and simulation modelling methods. This specifically involved the possible use of D to predict the values of other egg parameters. The theoretically derived equation for D enabled us to reduce a number of parameters that affect the value of D. Herewith, we suggested that it would be more suitable for planning experiments and promising for studying eggs of various bird species to use parameter ratios rather than their original values. On the basis of simulation methods, we generated and analyzed an extensive database of ‘virtual’ chicken eggs that included all possible variations of the parameters from the proposed D equation. We established that the most influential factor on D is the density of egg interior (Di) and the most predictable parameter by the D value is the shell thickness (T). Approximation of the obtained data on the dependence of T on D led to a prediction accuracy of R = 0.68. We also demonstrated that the ratio Di/D was more dependent on the ratio of shell volume to whole egg volume and can be a very promising criterion for developing a new avenue of research on pre-incubational sorting of eggs. To refine the accuracy of prediction using this criterion, a further development of more efficient and precise methods for non-destructive measurement of T and Ds will be required.

Ultradian rhythms in shell composition of photosymbiotic and non-photosymbiotic mollusks

Abstract. The chemical composition of mollusk shells is a useful tool in (paleo)climatology since it captures inter- and intra-annual variability in environmental conditions. Trace element and stable isotope analysis with improved sampling resolution now allows in situ determination of the composition of mollusk shell volumes precipitated at daily to sub-daily time intervals. Here, we discuss hourly resolved Mg / Ca, Mn / Ca, Sr / Ca, and Ba / Ca profiles measured by laser ablation inductively coupled plasma – mass spectrometry (ICP-MS) through shells of the photosymbiotic giant clams (Tridacna maxima, T. squamosa, and T. squamosina) and the non-photosymbiotic scallop Pecten maximus. Precise sclerochronological age models and spectral analysis allowed us to extract daily and tidal rhythms in the trace element composition of these shells. We find weak but statistically significant expressions of these periods and conclude that this cyclicity explains less than 10 % of the sub-annual variance in trace element profiles. Tidal and diurnal rhythms explain variability of, at most, 0.2 mmol mol−1 (∼ 10 % of mean value) in Mg / Ca and Sr / Ca, while ultradian Mn / Ca and Ba / Ca cyclicity has a median amplitude of less than 2 µmol mol−1 mol mol−1 (∼ 40 % and 80 % of the mean of Mn / Ca and Ba / Ca, respectively). Daily periodicity in Sr / Ca and Ba / Ca is stronger in Tridacna than in Pecten, with Pecten showing stronger tidal periodicity. One T. squamosa specimen which grew under a sunshade exhibits among the strongest diurnal cyclicity. Daily cycles in the trace element composition of giant clams are therefore unlikely to be driven by variations in direct insolation but rather reflect an inherent biological rhythmic process affecting element incorporation. Finally, the large amount of short-term trace element variability unexplained by tidal and daily rhythms highlights the dominance of aperiodic processes in mollusk physiology and/or environmental conditions over shell composition at the sub-daily scale. Future studies should aim to investigate whether this remaining variability in shell chemistry reliably records weather patterns or circulation changes in the animals' environment.

Do African egg‐eating snakes (Dasypeltis) exhibit preference for eggs they eat?

AbstractAfrican egg‐eating snakes (genus Dasypeltis) are medium‐sized obligate egg‐eating species capable of swallowing large eggs compared to facultative egg‐eating snakes of the same size. Dasypeltis have numerous adaptations for swallowing then crushing eggs to extract the content. Being dependent on an egg diet, it could be predicted that Dasypeltis have the ability to assess the quality of an egg then decide whether to reject or swallow it. For example, a small egg provides less food and takes less time to swallow than a large egg but swallowing a large egg could leave the snake more vulnerable to predation. Despite the possibility of Dasypeltis exhibiting egg preference, little research has addressed this. This study examined egg preference by five species of Dasypeltis in two laboratory experiments. In the first, five species of snakes were given a choice of the widest size range of eggs available from one order of birds. These included nine species of gallinaceous birds ranging from small, soft‐shelled king quail eggs to large, hard‐shelled turkey eggs. In the second experiment, snakes were given a choice of four eggs representing three genera of birds that occur in Africa represented by two galliform and two columbiform species. These eggs varied in volume, color, and hardness of shell. The results show Dasypeltis preferred certain eggs. Large snakes eat eggs of all sizes with preference for the largest, hardest eggs, while the smallest snakes ate only the smallest eggs. Snakes preferred columbiform eggs (dove and pigeon) over galliform eggs (king quail and Japanese quail). This study demonstrated that Dasypeltis in captivity do exhibit preferences for types and sizes of eggs.

The influence of upwelling on key bivalves from the Humboldt and Iberian current systems

Eastern Boundary Upwelling Systems (EBUS) deliver cold, nutrient-rich waters, influencing coastal biota from the molecular to the ecosystem level. Although local upwelling (U) and downwelling (DU) conditions are often known, their influence on body attributes of relevant species has not been systematically compared within and between EBUS (i.e., below and above regional scales). Hence, we compared the physical-chemical characteristics of U and DU sites in the Humboldt Current system (Chile) and the Iberian Current system (Portugal). We then assessed the influence of U and DU upon eight body attributes in purple mussels (Perumytilus purpuratus) and Mediterranean mussels (Mytilus galloprovincialis), from the Humboldt and Iberian systems, respectively. We hypothesized that bivalves from U sites display better fitness, as measured by body attributes, regardless of their origin (EBUS). As expected, waters from U sites in both systems showed lower temperatures and pH, and higher nitrite concentrations. We also found that mussels from U sites showed better fitness than those in DU sites in 12 out of 16 direct U vs DU comparisons. Shell length, shell volume, organic content of soft-tissues, and mechanical properties of the shell averaged consistently higher in mussels from U sites in both Current systems. In addition, total weight, soft-tissue weight, shell weight and shell thickness were all higher in the U site at the Humboldt system but had less consistent differences at the Iberian system. Altogether, most results supported our working hypothesis and indicate that U conditions support better fitted mussels. The few attributes that did not exhibit the expected U vs DU differences in the Iberian system suggest that local and species-specific differences also play a role on the attributes of these species. These results may also serve as a reference point for further studies addressing the influence of upwelling in these productive, critically important systems.