Comparative responses of two dominant Antarctic phytoplankton taxa to interactions between ocean acidification, warming, irradiance, and iron availability

We investigated the responses of the ecologically dominant Antarctic phytoplankton species Phaeocystis antarctica (a prymnesiophyte) and Fragilariopsis cylindrus (a diatom) to a clustered matrix of three global change variables (CO2, mixed-layer depth, and temperature) under both iron (Fe)-replete and Fe-limited conditions based roughly on the Intergovernmental Panel on Climate Change (IPCC) A2 scenario: (1) Current conditions, 39 Pa (380 ppmv) CO2, 50 µmol photons/m**2/s light, and 2°C; (2) Year 2060, 61 Pa (600 ppmv) CO2, 100 µmol photons/m**2/s light, and 4°C; (3) Year 2100, 81 Pa (800 ppmv) CO2, 150 µmol photons/m**2/s light, and 6°C. The combined interactive effects of these global change variables and changing Fe availability on growth, primary production, and cell morphology are species specific. A competition experiment suggested that future conditions could lead to a shift away from P. antarctica and toward diatoms such as F. cylindrus. Along with decreases in diatom cell size and shifts from prymnesiophyte colonies to single cells under the future scenario, this could potentially lead to decreased carbon export to the deep ocean. Fe : C uptake ratios of both species increased under future conditions, suggesting phytoplankton of the Southern Ocean will increase their Fe requirements relative to carbon fixation. The interactive effects of Fe, light, CO2, and temperature on Antarctic phytoplankton need to be considered when predicting the future responses of biology and biogeochemistry in this region.

Sea urchins in a high CO2 world: partitioned effects of body-size, ocean warming and acidification on metabolic rate

Body-size and temperature are the major factors explaining metabolic rate, and the additional factor of pH is a major driver at the biochemical level. These three factors have frequently been found to interact, complicating the formulation of broad models predicting metabolic rates and hence ecological functioning. In this first study of the effects of warming and ocean acidification, and their potential interaction, on metabolic rate across a broad body-size range (two-to-three orders of magnitude difference in body mass) we addressed the impact of climate change on the sea urchin Heliocidaris erythrogramma in context with climate projections for east Australia, an ocean warming hotspot. Urchins were gradually introduced to two temperatures (18 and 23 °C) and two pH (7.5 and 8.0), and maintained for two months. That a new physiological steady-state had been reached, otherwise know as acclimation, was validated through identical experimental trials separated by several weeks. The relationship between body-size, temperature and acidification on the metabolic rate of H. erythrogramma was strikingly stable. Both stressors caused increases in metabolic rate; 20% for temperature and 19% for pH. Combined effects were additive; a 44% increase in metabolism. Body-size had a highly stable relationship with metabolic rate regardless of temperature or pH. None of these diverse drivers of metabolism interacted or modulated the effects of the others, highlighting the partitioned nature of how each influences metabolic rate, and the importance of achieving a full acclimation state. Despite these increases in energetic demand there was very limited capacity for compensatory modulating of feeding rate; food consumption increased only in the very smallest specimens, and only in response to temperature, and not pH. Our data show that warming, acidification and body-size all substantially affect metabolism and are highly consistent and partitioned in their effects, and for H. erythrogramma near-future climate change will incur a substantial energetic cost.

Short- and long-term conditioning of a temperate marine diatom community to acidification and warming

Ocean acidification and greenhouse warming will interactively influence competitive success of key phytoplankton groups such as diatoms, but how long-term responses to global change will affect community structure is unknown. We incubated a mixed natural diatom community from coastal New Zealand waters in a short-term (two-week) incubation experiment using a factorial matrix of warming and/or elevated pCO2 and measured effects on community structure. We then isolated the dominant diatoms in clonal cultures and conditioned them for 1 year under the same temperature and pCO2 conditions from which they were isolated, in order to allow for extended selection or acclimation by these abiotic environmental change factors in the absence of interspecific interactions. These conditioned isolates were then recombined into 'artificial' communities modelled after the original natural assemblage and allowed to compete under conditions identical to those in the short-term natural community experiment. In general, the resulting structure of both the unconditioned natural community and conditioned 'artificial' community experiments was similar, despite differences such as the loss of two species in the latter. pCO2 and temperature had both individual and interactive effects on community structure, but temperature was more influential, as warming significantly reduced species richness. In this case, our short-term manipulative experiment with a mixed natural assemblage spanning weeks served as a reasonable proxy to predict the effects of global change forcing on diatom community structure after the component species were conditioned in isolation over an extended timescale. Future studies will be required to assess whether or not this is also the case for other types of algal communities from other marine regimes.

Sobre el origen del Mapa Geológico de España. El Mapa Geognóstico de los alrededores de Burgos de Felipe Naranjo y Garza (1841)

En el año 1841 se publicó en la revista Anales de Minas, acompañando a una memoria explicativa sobre la geología y minería de la provincia de Burgos, una cartografía geológica a escala próxima a 1:350.000. En el mapa se definen ya los tres principales rasgos litoestructurales que forman la geología de la provincia de Burgos. La memoria, por su parte, además de la geología, incide en la minería de la zona estudiada, en la que destaca la descripción de las salinas de Poza de la Sal. El autor, Felipe Naranjo y Garza (1809-1877), fue uno de los primeros ingenieros de minas españoles que, desde los múltiples puestos que desempeñó en la administración, destacó por su contribución al desarrollo de la geología en España y en sus intentos de modernizar la industria minera. En el presente trabajo pretendemos dar a conocer esta precoz cartografía geológica y analizar dicha obra científica situándola en el contexto en que se encontraba la geología española en la primera mitad del siglo XLX.

Case-Study Schorlemerallee: intervención en el patrimonio residencial moderno. La Versuchsiedlung (colonia experimental) de Wassili y Hans Luckhardt y Alfons Anker en Berlín 1924-30

La Versuchssiedlung (Colonia experimental de viviendas) de Schorlemerallee (Berlin-Dahlem) proyectada y construida entre los años 1924 y 1930 por los hermanos Wassili y Hans Luckhardt con Alfons Anker, es un proyecto personal basado en la investigación sobre distintas técnicas constructivas, sus posibilidades, condicionantes y limitaciones. La Colonia Experimental reúne en un espacio relativamente reducido todo un campo de investigación de sistemas constructivos que permitieron a sus autores (y nos permiten a nosotros) el análisis comparado. Por otra parte la evolución de las viviendas a través de los años, y los distintos acontecimientos y circunstancias históricas que han atravesado (incluyendo una guerra mundial, una dura posguerra y numerosas alteraciones y modificaciones), con resultados muy diversos hasta llegar a su estado actual, son una oportunidad única, una espléndida muestra espectográfica del estado, posibilidades y problemas a la hora de abordar la intervención en el patrimonio residencial moderno

Recopilación y comentarios de los fueros y leyes del antiguo Reino de Navarra que han quedado vigentes después de la modificación hecha por la Ley Paccionada de 16 de agosto de 1841 / por José Alonso.

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