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Continuous emissions of anthropogenic CO 2 are changing the atmospheric and oceanic environment. Although some species may have compensatory mechanisms to acclimatize or adapt to the changing environment, most marine organisms are negatively influenced by climate change. In this study, we aimed to understand the compensatory mechanisms of the Antarctic clam, Laternula elliptica , to climate-related stressors by using archived shells from 1995 to 2018. Principal component analysis revealed that seawater p CO 2 and salinity in the Antarctic Ocean, which have increased since the 2000's, are the most influential factors on the characteristics of the shell. The periostracum thickness ratio and nitrogen on the outermost surface have increased, and the dissolution area (%) has decreased. Furthermore, the calcium content and mechanical properties of the shells have not changed. The results suggest that L. elliptica retains the mechanism of protecting the shell from high p CO 2 by thickening the periostracum as a phenotype plasticity. [Display omitted] • We analyzed archival shells of the Antarctic clams in response to climate change. • Seawater p CO 2 and salinity in the Antarctic Ocean have increased since the 2000's. • Shell dissolution decreased over time while total shell thickness remained constant. • The calcium content and mechanical properties of the shell remained unchanged. • Shell integrity was retained by thickening the organic layer enriched with nitrogen. [ABSTRACT FROM AUTHOR]

The aging laying hens are considered uneconomical due to low egg laying percentage, lower feed efficiency and decreased egg shell calcification. Dietary administration of organic acids can alleviate these problems by reducing the pH and increasing the length and depth of villi of the gastrointestinal tract enhancing thereby the digestibility of nutrients, absorption of minerals (Ca and P) and escalation of protein utilization through increased secretion and activity of the enzyme 'Pepsin', which is beneficial for both, the environment and the production economy. Paucity of information on this aspect inspired us to take up this study. Eighty H&N Brown Nick laying hens (79-88 weeks of age) were used to assess the impact of dietary supplementation of formic acid, propionic acid and their combination on the productive performance, egg quality, shell characteristics and some blood biochemical parameters during the late stage of production. Hens were randomly distributed into 4 groups. Each group contained 10 replicates with 2 hens/ replicate. The treatments were C (Basal diet), T1 (0.5 ml formic acid / kg diet), T2 (0.5 ml propionic acid / kg diet) and T3 (0.5 ml formic acid + 0.5 ml propionic acid / kg diet).The hens were given iso-nitrogenous (17.6% CP) and iso-caloric (2800 Kcal ME/Kg) basal diet. In comparison with the control, the treatments of acids and/or their mixture revealed a highly significant increase (P<0.001) in hen-day egg production and daily egg mass with reduction (P<0.001) in the feed intake and improvement (P<0.001) in the feed conversion ratio. The heaviest (P<0.001) egg weight was observed with formic acid (T1). Shell thickness, shell weight and shell surface area were significantly increased (P<0.05) with organic acids compared to the control. Propionic acid recorded the highest value (P<0.05) of plasma globulin and total antioxidant capacity (TAC) and the lowest (P<0.05) albumin/globulin ratio. The addition of formic acid alone (T1) or mixed with propionic acid (T3) caused significant reduction (P<0.05) in plasma cholesterol, while insignificant reduction in triglycerides was observed with formic acid treatment (T1). Plasma urea was significantly decreased (P<0.05) by the addition of acids compared to the control, while propionic acid (T2) and mixture of formic acid and propionic acid treatments (T3) recorded the lowest (P<0.05) plasma creatinine. The differences among treatments regarding alanine transaminase (ALT) and aspartic transaminase (AST) were nonsignificant (P>0.05). There are a tendency to increase (P=0.07) the gross energy content (kcal/ kg) of the internal egg components with propionic acid (T2) and acid mixture (T3) compared to the other treatments. It is concluded that organic acids supplementation in laying hens' diet during the late stage of production had positive effects on the productivity and the re lated economic traits, besides bolstering immunity, that conferred protection against infectious diseases, without any adverse effects on the liver and kidney functions. [ABSTRACT FROM AUTHOR]

Invasive species often show greater morphological plasticity than do native species. This plasticity increases their ability to evade predation, but differences in morphological defenses between sexes, including both dimorphism and predator-induced plasticity, remain poorly understood. We measured multiple shell characteristics of male and female adults of the invasive freshwater snail Pomacea canaliculata after they had been exposed to predation cues from the caged turtle Trachemys scripta elegans for 30 d. Regardless of sex, P. canaliculata individuals exhibited greater shell crushing (i.e., higher shell strength) and shell entry (i.e., smaller opercula) resistance characteristics and a narrower shape under predator-induced stress. Moreover, the snails exhibited sexual dimorphism in shell shape and strength characteristics. The shell crushing resistance capability of males was stronger than that of females in both the presence and absence of non-consumptive effects of predators, a difference that could be linked to shell thickness, mass, and calcium concentration. However, females had smaller opercula than males regardless of the presence of predators, which might allow them to better resist predator attacks on snail flesh via the aperture. The snails exhibited sex-specific body size plasticity responses to the predation threat such that shell height growth of females was inhibited in the presence of predators, whereas the shell height of males was unaffected. In general, males appeared to have stronger morphological defenses than females. These results indicate that energy allocation to shell morphological defense, growth, and reproduction differ between the 2 sexes under non-consumptive effects of predators, which might be a result of their different morphology and reproductive roles. [ABSTRACT FROM AUTHOR]

The inability of organisms to cope in changing environments poses a major threat to their survival. Rising carbon dioxide concentrations, recently exceeding 400 latm, are rapidly warming and acidifying our oceans. Current understanding of organism responses to this environmental phenomenon is based mainly on relatively short- to medium-term laboratory and field experiments, which cannot evaluate the potential for long-term acclimation and adaptation, the processes identified as most important to confer resistance. Here, we present data from a novel approach that assesses responses over a centennial timescale showing remarkable resilience to change in a species predicted to be vulnerable. Utilising museum collections allows the assessment of how organisms have coped with past environmental change. It also provides a historical reference for future climate change responses. We evaluated a unique specimen collection of a single species of brachiopod (Calloria inconspicua) collected every decade from 1900 to 2014 from one sampling site. The majority of brachiopod shell characteristics remained unchanged over the past century. One response, however, appears to reinforce their shell by constructing narrower punctae (shell perforations) and laying down more shell. This study indicates one of the most calcium-carbonate-dependent species globally to be highly resilient to environmental change over the last 120 years and provides a new insight for how similar species might react and possibly adapt to future change. [ABSTRACT FROM AUTHOR]

Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres' shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy (SEM), energy- dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness. [ABSTRACT FROM AUTHOR]

Along wave-protected shores of the northeastern Pacific, the demography and life history of Littorina sitkana vary with intertidal zone, producing spatially close, but separate, “populations” (high- and low-shore). Field sampling (at multiple sites in the wave-sheltered Bamfield Inlet, B.C., Canada), a common garden experiment, and genetic analysis were used to determine if these two “populations” should be considered a panmictic population or different locally adapted populations (ecotypes). In the field, shell mass and incidence of white shells were greater for low-shore than high-shore snails, complementing other previously documented phenotypic differences (growth rate, size at sexual maturity). The common garden experiment revealed patterns of genetically-based phenotypic variation between the populations. Genetic analysis using a mitochondrial marker ( COI ) and a nuclear maker ( APN54 ) did not resolve any spatial population genetic structure, but did confirm the absence of cryptic species. In the context of work on another littorinid ( Littorina saxatilis ), our study points to L . sitkana being an interesting species for further investigation of genetic differentiation between different populations depending on their position in the intertidal shore ecotone. [ABSTRACT FROM AUTHOR]

The nut weevil Curculio nucum (Coleoptera: Curculionidae) is responsible for high yield losses in several hazelnut-growing areas of Europe and Turkey, if not regularly controlled using pesticides. The resistance of hazelnut varieties to the nut weevil is known but poorly investigated so far. Thus a 2-year study was carried out to investigate factors affecting C. nucum attacks on two cultivars [Tonda Gentile delle Langhe (TGL), Ennis] and four selections (Daria, 101, B6, L35) in a 15-year-old orchard of northwestern Italy. Nut developmental stages and shell characteristics, such as hardness and thickness, were measured and correlated to the biological cycle of the nut weevil and to the damage by its larvae. During the 2-year sampling, nut weevil adults were collected on all cultivars and selections, but in greater quantities on TGL and Daria, and in lower quantities on 101 and B6. In 2005, by female dissection, mature eggs were observed from late June, when the mean temperature exceeded 18°C. Differences between cultivars and selections were found in nut and kernel development, and in shell hardening; in particular, the kernel development was directly related with the shell hardness. At harvest, the damage varied on average from 2.57% in cultivar TGL to 51.84% in selection 101 of total nuts harvested, so independently of the numbers of the collected weevil adults. These two varieties were the earliest and the latest in kernel development and shell hardening, respectively. Therefore, the susceptibility to nut weevil attacks was strictly related to shell hardening; in fact, a rapid hardening of the shell can hamper the oviposition of C. nucum females. By contrast, no correlation was found between shell thickness and damage at harvest. [ABSTRACT FROM AUTHOR]