Seawater carbonate chemistry and biological processes of Mytilus edulis during experiments, 2011

Progressive ocean acidification due to anthropogenic CO2 emissions will alter marine ecosytem processes. Calcifying organisms might be particularly vulnerable to these alterations in the speciation of the marine carbonate system. While previous research efforts have mainly focused on external dissolution of shells in seawater under saturated with respect to calcium carbonate, the internal shell interface might be more vulnerable to acidification. In the case of the blue mussel Mytilus edulis, high body fluid pCO2 causes low pH and low carbonate concentrations in the extrapallial fluid, which is in direct contact with the inner shell surface. In order to test whether elevated seawater pCO2 impacts calcification and inner shell surface integrity we exposed Baltic M. edulis to four different seawater pCO2 (39, 142, 240, 405 Pa) and two food algae (310-350 cells mL-1 vs. 1600-2000 cells mL-1) concentrations for a period of seven weeks during winter (5°C). We found that low food algae concentrations and high pCO2 values each significantly decreased shell length growth. Internal shell surface corrosion of nacreous ( = aragonite) layers was documented via stereomicroscopy and SEM at the two highest pCO2 treatments in the high food group, while it was found in all treatments in the low food group. Both factors, food and pCO2, significantly influenced the magnitude of inner shell surface dissolution. Our findings illustrate for the first time that integrity of inner shell surfaces is tightly coupled to the animals' energy budget under conditions of CO2 stress. It is likely that under food limited conditions, energy is allocated to more vital processes (e.g. somatic mass maintenance) instead of shell conservation. It is evident from our results that mussels exert significant biological control over the structural integrity of their inner shell surfaces.

Experiment: Food availability outweighs ocean acidification effects in juvenile Mytilus edulis

Ocean acidification is expected to decrease calcification rates of bivalves. Nevertheless in many coastal areas high pCO2 variability is encountered already today. Kiel Fjord (Western Baltic Sea) is a brackish (12-20 g kg-1) and CO2 enriched habitat, but the blue mussel Mytilus edulis dominates the benthic community. In a coupled field and laboratory study we examined the annual pCO2 variability in this habitat and the combined effects of elevated pCO2 and food availability on juvenile M. edulis growth and calcification. In the laboratory experiment, mussel growth and calcification were found to chiefly depend on food supply, with only minor impacts of pCO2 up to 3350 µatm. Kiel Fjord was characterized by strong seasonal pCO2 variability. During summer, maximal pCO2 values of 2500 µatm were observed at the surface and >3000 µatm at the bottom. However, the field growth experiment revealed seven times higher growth and calcification rates of M. edulis at a high pCO2 inner fjord field station (mean pCO2 ca. 1000 µatm) in comparison to a low pCO2 outer fjord station (ca. 600 µatm). In addition, mussels were able to outcompete the barnacle Amphibalanus improvisus at the high pCO2 site. High mussel productivity at the inner fjord site was enabled by higher particulate organic carbon concentrations. Kiel Fjord is highly impacted by eutrophication, which causes bottom water hypoxia and consequently high seawater pCO2. At the same time, elevated nutrient concentrations increase the energy availability for filter feeding organisms such as mussels. Thus M. edulis can dominate over a seemingly more acidification resistant species such as A. improvisus. We conclude that benthic stages of M. edulis tolerate high ambient pCO2 when food supply is abundant and that important habitat characteristics such as species interactions and energy availability need to be considered to predict species vulnerability to ocean acidification.

Effects of seawater pCO2 and temperature on shell growth, shell stability, condition and cellular stress of Western Baltic Sea Mytilus edulis (L.) and Arctica islandica (L.)

Acidification of the World's oceans may directly impact reproduction, performance and shell formation of marine calcifying organisms. In addition, since shell production is costly and stress in general draws on an organism's energy budget, shell growth and stability of bivalves should indirectly be affected by environmental stress. The aim of this study was to investigate whether a combination of warming and acidification leads to increased physiological stress (lipofuscin accumulation and mortality) and affects the performance [shell growth, shell breaking force, condition index (Ci)] of young Mytilus edulis and Arctica islandica from the Baltic Sea. We cultured the bivalves in a fully-crossed 2-factorial experimental setup (seawater (sw) pCO2 levels "low", "medium" and "high" for both species, temperature levels 7.5, 10, 16, 20 and 25 °C for M. edulis and 7.5, 10 and 16 °C for A. islandica) for 13 weeks in summer. Mytilus edulis and A. islandica appeared to tolerate wide ranges of sw temperature and pCO2. Lipofuscin accumulation of M. edulis increased with temperature while the Ci decreased, but shell growth of the mussels only sharply decreased while its mortality increased between 20 and 25 °C. In A. islandica, lipofuscin accumulation increased with temperature, whereas the Ci, shell growth and shell breaking force decreased. The pCO2 treatment had only marginal effects on the measured parameters of both bivalve species. Shell growth of both bivalve species was not impaired by under-saturation of the sea water with respect to aragonite and calcite. Furthermore, independently of water temperatures shell breaking force of both species and shell growth of A. islandica remained unaffected by the applied elevated sw pCO2 for several months. Only at the highest temperature (25 °C), growth arrest of M. edulis was recorded at the high sw pCO2 treatment and the Ci of M. edulis was slightly higher at the medium sw pCO2 treatment than at the low and high sw pCO2 treatments. The only effect of elevated sw pCO2 on A. islandica was an increase in lipofuscin accumulation at the high sw pCO2 treatment compared to the medium sw pCO2 treatment. Our results show that, despite this robustness, growth of both M. edulis and A. islandica can be reduced if sw temperatures remain high for several weeks in summer. As large body size constitutes an escape from crab and sea star predation, this can make bivalves presumably more vulnerable to predation with possible negative consequences on population growth. In M. edulis, but not in A. islandica, this effect is amplified by elevated sw pCO2. We follow that combined effects of elevated sw pCO2 and ocean warming might cause shifts in future Western Baltic Sea community structures and ecosystem services; however, only if predators or other interacting species do not suffer as strong from these stressors.

Ocean acidification alters the material properties of Mytilus edulis shells

Ocean acidification (OA) and the resultant changing carbonate saturation states is threatening the formation of calcium carbonate shells and exoskeletons of marine organisms. The production of biominerals in such organisms relies on the availability of carbonate and the ability of the organism to biomineralize in changing environments. To understand how biomineralizers will respond to OA the common blue mussel, Mytilus edulis, was cultured at projected levels of pCO2 (380, 550, 750, 1000 µatm) and increased temperatures (ambient, ambient plus 2°C). Nanoindentation (a single mussel shell) and microhardness testing were used to assess the material properties of the shells. Young's modulus (E), hardness (H) and toughness (KIC) were measured in mussel shells grown in multiple stressor conditions. OA caused mussels to produce shell calcite that is stiffer (higher modulus of elasticity) and harder than shells grown in control conditions. The outer shell (calcite) is more brittle in OA conditions while the inner shell (aragonite) is softer and less stiff in shells grown under OA conditions. Combining increasing ocean pCO2 and temperatures as projected for future global ocean appears to reduce the impact of increasing pCO2 on the material properties of the mussel shell. OA may cause changes in shell material properties that could prove problematic under predation scenarios for the mussels; however, this may be partially mitigated by increasing temperature.

Desenvolvimento e avaliação de sorbets probióticos e simbióticos elaborados com polpa de Juçara (Euterpe edulis)

O objetivo deste trabalho foi desenvolver e avaliar diferentes formulações de sorbets probióticos e simbióticos a base de polpa de juçara (Euterpe edulis), de modo a combinar os efeitos benéficos à saúde dos compostos fenólicos deste fruto com os benefícios dos probióticos e prebióticos. Para isso, foram utilizados os microrganismos L. acidophilus e L. paracasei e a fibra polidextrose, além da elaboração de uma amostra controle sem tais elementos para efeito de comparação. Primeiramente, a polpa de juçara pasteurizada utilizada na produção dos sorbets foi avaliada de acordo com suas características físico-químicas e seus compostos bioativos, tendo apresentado resultados adequados para o emprego na matriz alimentícia em questão. Em seguida, os sorbets foram caracterizados através de diversos parâmetros. Assim, a análise centesimal mostrou sorbets com alto índice de carboidratos e baixo valor calórico, enquanto os teores de sólidos solúveis apresentaram-se coerentes em todas as formulações analisadas. Os valores de overrun e densidade aparente relevaram que a incorporação de ar dos sorbets não foi tão elevada quanto de um sorvete lácteo, embora as amostras adicionadas de polidextrose - capaz de mimetizar as propriedades de corpo e espessamento da gordura - tenham obtido resultados mais próximos aos gelados tradicionais. Foram ainda mensurados os efeitos do armazenamento dos produtos a -18 °C durante 120 dias, através de avaliações de pH, coloração instrumental, estabilidade dos compostos fenólicos e antocianinas e viabilidade dos probióticos. O pH das amostras manteve-se constante durante todo o experimento, com valores entre 4,4 e 4,8, enquanto os parâmetros de coloração caracterizaram as amostras como vermelhas e apontaram tendência à perda de luminosidade. Já os polifenóis e antocianinas apresentaram teores elevados, decorrentes da adição da polpa de juçara, sem a ocorrência de degradação destes compostos ao longo da estocagem das amostras sob congelamento. As populações de ambos os microrganismos adicionados apresentaram-se estáveis em cerca de 8 log UFC/ g durante todo o período de armazenamento, o que corresponde a um resultado bastante satisfatório e superior ao recomendado pela legislação brasileira. Por outro lado, a sobrevivência in vitro de tais probióticos quando submetidos aos fluidos gastrointestinais não apresentou resultados adequados para a garantia da funcionalidade destes produtos, com queda de viabilidade superior a 4 ciclos logarítmicos. A aceitabilidade sensorial e intenção de compra apresentaram resultados positivos para todas as formulações, com maior aceitação das amostras probióticas em relação ao controle e menor interesse pelas amostras com adição de prebiótico. Tal resultado demonstra que a incorporação destas bactérias em sorbets de juçara é capaz de melhorar a qualidade do produto, enquanto a adição de polidextrose pode diminuir sua aceitabilidade nas condições empregadas. Em síntese, os sorbets elaborados apresentaram resultados satisfatórios, demonstrando a viabilidade na produção deste tipo de alimento funcional adicionado de probióticos, prebiótico e rico em polifenóis, sendo a combinação de tais elementos capaz de potencializar os efeitos benéficos destes compostos e trazer vantagens fundamentais à microbiota intestinal e à saúde de quem os consome.

Detección de simulación de trastorno mental: un estudio de análogos en población militar española mediante los inventarios PAI, MMPI-2RF y SIMS

La simulación de enfermedad ha estado siempre asociada a la evitación de deberes militares. Tanto es así, que la etimología de la palabra malingering (simulación en inglés) proviene de la vida militar. De hecho, los principales manuales de diagnóstico psiquiátrico todavía mantienen los contextos militares como indicio para sospechar simulación. Además, esta forma de evitar obligaciones públicas se concebía como un intento de deserción y, en consecuencia, se identificaba con la cobardía y la deslealtad. Los Códigos de Justicia Militar de diferentes países así lo han contemplado y, en consecuencia, condenado. Debido a que la mayoría de los problemas psicológicos carecen de sustrato biológico, esta área de la salud ha estado inmersa en la subjetividad, favoreciendo que se relacionara, más que otras, con la sospecha de perfiles psicológicos deshonestos. En este contexto de arbitrariedad, los problemas mentales en población militar han sufrido un doble estigma. Por una parte, la fortaleza guerrera era incompatible con este tipo de problemas, convirtiéndolos en signo de debilidad. Mientras que, por otra, cualquier intento de evitación del servicio militar (como podían ser los problemas psicológicos aparentemente simulados) se asimilaba a un acto desleal. Por lo tanto, los soldados con problemas psicológicos -reales o simulados- eran estigmatizados, bien por debilidad, bien por cobardía o deslealtad. Así, ante las necesidades públicas de Defensa Territorial y/o Nacional, cristalizadas en una estricta cadena de mando cuyos objetivos eran incompatibles con la debilidad mental y la cobardía, la percepción de los problemas psicológicos partía de una visión intuitiva, cargada de connotaciones carentes de empatía y afianzada en este doble estigma. El problema para la sanidad militar –o los expertos de cada momento histórico- era determinar la veracidad de los cuadros psicopatológicos de los soldados, pero sin pruebas objetivas en las que basarse y bajo la presión de la cadena de mando...

Immunomodulating effects of environmentally realistic copper concentrations in Mytilus edulis adapted to naturally low salinities, link to supplementary material

The monitoring of organisms' health conditions by the assessment of their immunocompetence may serve as an important criterion for the achievement of the Good Environmental Status (GES) as defined in the Marine Strategy Framework Directive (EU). In this context, the complex role of natural environmental stressors, e.g. salinity, and interfering or superimposing effects of anthropogenic chemicals, should be carefully considered, especially in scenarios of low to moderate contamination. Organisms from the Baltic Sea have adapted to the ambient salinity regime, however energetically costly osmoregulating processes may have an impact on the capability to respond to additional stress such as contamination. The assessment of multiple stressors, encompassing natural and anthropogenic factors, influencing an organisms' health was the main aim of the present study. Immune responses of Mytilus edulis, collected and kept at natural salinities of 12 per mil (LS) and 20 per mil (MS), respectively, were compared after short-term exposure (1, 7 and 13 days) to low copper concentrations (5, 9 and 16 µg/L Cu). A significant interaction of salinity and copper exposure was observed in copper accumulation. LS mussels accumulated markedly more copper than MS mussels. No combined effects were detected in cellular responses. Bacterial clearance was mostly achieved by phagocytosis, as revealed by a strong positive correlation between bacterial counts and phagocytic activity, which was particularly pronounced in LS mussels. MS mussels, on the other hand, seemingly accomplished bacterial clearance by employing additional humoral factors (16 µg/L Cu). The greatest separating factor in the PCA biplot between LS and MS mussels was the proportion of granulocytes and hyalinocytes while functional parameters (phagocytic activity and bacterial clearance) were hardly affected by salinity, but rather by copper exposure. In conclusion, immune responses of the blue mussel may be suitable and sensitive biomarkers for the assessment of ecosystem health in brackish waters (10-20 per mil S).

The International dry-farming congress, containing: the official call of the seventh international session, and exposition, at Lethbridge, Alberta, October 19-26, 1912. The dry-farming congress--its history, its sims, its successes. The province of Alberta ... its resources, its development, its possibilities, and the agricultural and industrial districts of southern Alberta. Pub. by the Department of agriculture of the province of Alberta, and the Board of control, of the seventh International dry-farming congress.

Edited by Charles S. Hotchkiss.

The poetical works of George R. Sims.

Mode of access: Internet.