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Invited lecture. Online live Session 2 Summary: trophic levels: a measure of functional diversity stable isotope tools: bulk vs. compound-specific analyses the basis: differential isotopic fractionation trophic indicators: trophic position, baselines, and much more application examples progress: multitrophic models, fingerprinting MCIN/AEI/10.13039/501100011033

ispartof: Fish Welfare Mini Symposium location:Oostende, Belgium date:29 Nov - 29 Nov 2019 status: Published online

Stress induced by high rearing density during the gonadal development period (7 to 45 days post fertilization, dpf) in domesticated zebrafish (Danio rerio) caused an increase in the number of males. Moreover, the ovarian transcriptome of fish subjected to high density had more than 3,000 differentially expressed genes (DEG) when compared to non-stressed fish. Further, it is known that DNA methylation is related to the masculinization process in fish during gonadal development. Thus, the goal of this study was to determine whether there was a direct relationship between stress and DNA methylation changes in fish gonads. Zebrafish larvae were subjected to two different treatments, one group reared at low density (9 fish/liter) and another group reared at high density (74 fish/liter) during their sexual differentiation period. Once fish reached adulthood, sex ratio and biometry were recorded and gonads were dissected and kept frozen at -80ºC. In order to test how DNA methylation patterns changed due to density, a set of eleven DEG related to sex (e.g., cyp19a1a and dmrt1), stress (e.g., β-hsd) and DNA methylation (e.g., dnmt1) were selected and analyzed by Multiplex Bisulfite Sequencing (MBS) to obtain the methylation level for each CpG in the promoter regions. Sequencing data was analyzed by bioinformatics tools (e.g., Bismark software) and results discussed in relation to the ability of high density stress as an environmental factor capable to cause long-lasting effects through changes in the DNA methylation VIII Jornada de Cromatina i Epigenètica organizada por la Secció de Cromatina i Epigenètica de la Societat Catalana de Biologia (SCB) con el Barcelona Chromatin Club (BCC), 16 March 2018, Barcelona.-- 1 page Peer Reviewed

Course Outline The aim of these lectures is to present the fundamentals of thermodynamics in the context of fluid flow and mixing in the ocean and the interaction of seawater and ice. The course will develop thermodynamic concepts that are needed to account for the flow of heat in the coupled atmosphere-ocean-ice system of planet earth. The thermophysical quantities in the ocean are functions of three variables, namely salinity, temperature and pressure, and this functional dependence complicates what is even meant by seemingly simple concepts such as "specific volume", "specific heat" and "heat content per unit mass". For example, what is a meaningful definition of an “isopycnal surface”? The ocean and atmosphere are in a continuous state of turbulent motion, and the course will derive the appropriate theoretical framework in which these time varying motions should be examined. This course introduces the conservation laws that govern the fluid dynamics the ocean, in particular concentrating on what variables should be carried in ocean models given that the ocean is subject to turbulent fluxes rather than simply molecular fluxes of heat and salt. The distinctions between variables that are conservative versus those that are non-conservative are emphasized. Several new results on the interaction of seawater and ice, and particularly of frazil ice, will be introduced. These results add thermodynamic rigor to existing practices. This rigor is now possible because the thermodynamic properties of seawater, ice and humid air have been redefined in 2010, as adopted by the Intergovernmental Oceanographic Commission. Frazil ice is the name used when small crystals of ice form in cold seawater such as occurs at the underside of ice shelves near the poles. The course will explore some of the implications of this thermodynamic knowledge for how oceanic data should be analyzed. For example, it is possible to developed a closed expression for the mean absolute velocity in the ocean, but it seems to depend on the local value “neutral helicity” of the ocean; a property that is normally understood as being the course of the mathematically ill-defined nature of neutral density surfaces in the ocean. Results such as this are at the edge of our oceanographic understanding and need further research. We now know that diapycnal mixing in the deep ocean is stronger near the sea floor. The course will discuss the dynamical implications of this bottom-intensification of diapycnal mixing. We will find that the net diapycnal upwelling of Bottom Water is actually the net GEOMAR Thermodynamics and Ocean Mixing Lectures, Sep. 2018 result of a larger upwelling across density surfaces in the bottom boundary layer partially offset by diapycnal sinking motion in the ocean interior.