Reefs shift from net accretion to net erosion along a natural environmental gradient

Coral reefs persist in an accretion-erosion balance and ocean acidification resulting from anthropogenic CO2 emissions threatens to shift this balance in favor of net reef erosion. Corals and calcifying algae, largely responsible for reef accretion, are vulnerable to environmental changes associated with ocean acidification, but the direct effects of lower pH on reef erosion has received less attention, particularly in the context of known drivers of bioerosion and natural variability. This study examines the balance between reef accretion and erosion along a well-characterized natural environmental gradient in Kane'ohe Bay, Hawai'i using experimental blocks of coral skeleton. Comparing before and after micro-computed tomography (µCT) scans to quantify net accretion and erosion, we show that, at the small spatial scale of this study (tens of meters), pH was a better predictor of the accretion-erosion balance than environmental drivers suggested by prior studies, including resource availability, temperature, distance from shore, or depth. In addition, this study highlights the fine-scale variation of pH in coastal systems and the importance of microhabitat variation for reef accretion and erosion processes. We demonstrate significant changes in both the mean and variance of pH on the order of meters, providing a local perspective on global increases in pCO2. Our findings suggest that increases in reef erosion, combined with expected decreases in calcification, will accelerate the shift of coral reefs to an erosion-dominated system in a high-CO2 world. This shift will make reefs increasingly susceptible to storm damage and sea-level rise, threatening the maintenance of the ecosystem services that coral reefs provide.

PLN : The paradigm shift in teacher and learner autonomy

This presentation explains a dozen tools and paradigm shifts that teachers should apply in transformative ways to working with their students, how Web 2.0, tagging, and RSS are crucial to this process, and how teachers can develop their own personal learning networks to practice continuous lifelong learning and 'teacher autonomy' before applying these concepts to students.

PLN : The paradigm shift in teacher and learner autonomy

This presentation explains a dozen tools and paradigm shifts that teachers should apply in transformative ways to working with their students, how Web 2.0, tagging, and RSS are crucial to this process, and how teachers can develop their own personal learning networks to practice continuous lifelong learning and 'teacher autonomy' before applying these concepts to students.

The shift of paradigm in the organizations like foundation of the style of ethical leadership

La presente investigación tiene por objeto analizar el cambio de paradigma en las organizaciones como fundamento del liderazgo ético desde una realidad postmoderna a fin de detectar la necesidad de un liderazgo ético en las organizaciones donde los líderes sean formadores de valores a través del modelaje directivo; es un estilo de liderazgo en el que la visión ética, sistémica e integradora son unas de las principales aptitudes que el líder ético ha de poner en la práctica. Se han desarrollado teorías de liderazgo centradas no tanto en los rasgos o comportamientos de los líderes, sino en la relación entre líder y sus seguidores

Aplicación de los Tableaux analíticos para la determinación de las relaciones de accesibilidad en Marcos de Kripke para la Lógica Modal Proposicional

Fil: Durán, Cecilia. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

PLN : The paradigm shift in teacher and learner autonomy

This presentation explains a dozen tools and paradigm shifts that teachers should apply in transformative ways to working with their students, how Web 2.0, tagging, and RSS are crucial to this process, and how teachers can develop their own personal learning networks to practice continuous lifelong learning and 'teacher autonomy' before applying these concepts to students.