¿Existen desigualdades en la formación de chicas y chicos en ciencias?

A nivel internacional, los estudios de género han suscitado recientemente mucho interés. Para conocer el éxito escolar de alumnas y alumnos en la superación de curso y evaluar posible diferencias de género, se recogen los datos de matrícula y de éxito escolar en Catalunya, desde el curso 1999-2000 hasta el 2008-2009, en cuatro momentos del itinerario escolar: sexto de Primaria, cuarto de ESO y primero y segundo de Bachillerato. El análisis de los datos incluye la discusión desde la perspectiva de la equidad en las tasa de graduación de niños y niñas, en Primaria y en Secundaria. La continuidad del estudio indica la necesidad de prestar atención de manera preferente a la variable de género en las propuestas e investigaciones en didáctica de las ciencias

Evidences of Impacts of Climate Change on Mediterranean Biota

Spanish Ministry of Economy and Competitiveness (projects ESTRESX CTM2012-32603 and CLIMPACT CGL2014-54246-C2-1-R). Ramón y Cajal contract (RYC-2013-14714) funded by the Spanish Ministry of Economy and Competitiveness and the Regional Government of the Balearic Islands.Peer Reviewe

Fairy circle landscapes under the sea

Short-scale interactions yield large-scale vegetation patterns that, in turn, shape ecosystem function across landscapes. Fairy circles, which are circular patches bare of vegetation within otherwise continuous landscapes, are characteristic features of semiarid grasslands. We report the occurrence of submarine fairy circle seascapes in seagrass meadows and propose a simple model that reproduces the diversity of seascapes observed in these ecosystems as emerging from plant interactions within the meadow. These seascapes include two extreme cases, a continuous meadow and a bare landscape, along with intermediate states that range from the occurrence of persistent but isolated fairy circles, or solitons, to seascapes with multiple fairy circles, banded vegetation, and "leopard skin" patterns consisting of bare seascapes patterns consisting of bare seascapes dotted with plant patches. The model predicts that these intermediate seascapes extending across kilometers emerge as a consequence of local demographic imbalances along with facilitative and competitive interactions among the plants with a characteristic spatial scale of 20 to 30 m, consistent with known drivers of seagrass performance. The model, which can be extended to clonal growth plants in other landscapes showing fairy rings, reveals that the different seascapes observed hold diagnostic power as to the proximity of seagrass meadows to extinction points that can be used to identify ecosystems at risks

Expanding Greenland seagrass meadows contribute new sediment carbon sinks

The loss of natural carbon sinks, such as seagrass meadows, contributes to grenhouse gas emissions and, thus, global warming. Whereas seagrass meadows are declining in temperate and tropical regions, they are expected to expand into the Arctic with future warming. Using paleoreconstruction of carbon burial and sources of organic carbon to shallow coastal sediments of three Greenland seagrass (Zostera marina) meadows of contrasting density and age, we test the hypothesis that Arctic seagrass meadows are expanding along with the associated sediment carbon sinks. We show that sediments accreted before 1900 were highly 13C depleted, indicative of low inputs of seagrass carbon, whereas from 1940’s to present carbon burial rates increased greatly and sediment carbon stocks were largely enriched with seagrass material. Currently, the increase of seagrass carbon inputs to sediments of lush and dense meadows (Kapisillit and Ameralik) was 2.6 fold larger than that of sparse meadows with low biomass (Kobbefjord). Our results demonstrate an increasing important role of Arctic seagrass meadows in supporting sediment carbon sinks, likely to be enhanced with future Arctic warming

Expanding Greenland seagrass meadows contribute new sediment carbon sinks

Unidad de excelencia María de Maeztu MdM-2015-0552The loss of natural carbon sinks, such as seagrass meadows, contributes to grenhouse gas emissions and, thus, global warming. Whereas seagrass meadows are declining in temperate and tropical regions, they are expected to expand into the Arctic with future warming. Using paleoreconstruction of carbon burial and sources of organic carbon to shallow coastal sediments of three Greenland seagrass (Zostera marina) meadows of contrasting density and age, we test the hypothesis that Arctic seagrass meadows are expanding along with the associated sediment carbon sinks. We show that sediments accreted before 1900 were highly 13C depleted, indicative of low inputs of seagrass carbon, whereas from 1940's to present carbon burial rates increased greatly and sediment carbon stocks were largely enriched with seagrass material. Currently, the increase of seagrass carbon inputs to sediments of lush and dense meadows (Kapisillit and Ameralik) was 2.6 fold larger than that of sparse meadows with low biomass (Kobbefjord). Our results demonstrate an increasing important role of Arctic seagrass meadows in supporting sediment carbon sinks, likely to be enhanced with future Arctic warming

Long photoperiods sustain high pH in Arctic kelp forests

Concern on the impacts of ocean acidification on calcifiers, such as bivalves, sea urchins, and foraminifers, has led to efforts to understand the controls on pH in their habitats, which include kelp forests and seagrass meadows. The metabolism of these habitats can lead to diel fluctuation in pH with increases during the day and declines at night, suggesting no net effect on pH at time scales longer than daily. We examined the capacity of subarctic and Arctic kelps to up-regulate pH in situ and experimentally tested the role of photoperiod in determining the capacity of Arctic macrophytes to up-regulate pH. Field observations at photoperiods of 15 and 24 hours in Greenland combined with experimental manipulations of photoperiod show that photoperiods longer than 21 hours, characteristic of Arctic summers, are conducive to sustained up-regulation of pH by kelp photosynthesis. We report a gradual increase in pH of 0.15 units and a parallel decline in pCO2 of 100 parts per million over a 10-day period in an Arctic kelp forest over midsummer, with ample scope for continued pH increase during the months of continuous daylight. Experimental increase in CO2 concentration further stimulated the capacity of macrophytes to deplete CO2 and increase pH. We conclude that long photoperiods in Arctic summers support sustained up-regulation of pH in kelp forests, with potential benefits for calcifiers, and propose that this mechanism may increase with the projected expansion of Arctic vegetation in response to warming and loss of sea ice.The study was funded by the Danish Environmental Protection Agency within the Danish Cooperation for Environment in the Arctic. It is also a contribution to the Greenland Ecosystem Monitoring program (www.G-E-M.dk) and the Arctic Science Partnership (www.asp-net.org). M.S.-M. was supported by a Fundación “La Caixa” fellowship (Spain). We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe

Sequestration of macroalgal carbon : the elephant in the Blue Carbon room

Unidad de excelencia María de Maeztu MdM-2015-0552Macroalgae form the most extensive and productive benthic marine vegetated habitats globally but their inclusion in Blue Carbon (BC) strategies remains controversial. We review the arguments offered to reject or include macroalgae in the BC framework, and identify the challenges that have precluded macroalgae from being incorporated so far. Evidence that macroalgae support significant carbon burial is compelling. The carbon they supply to sediment stocks in angiosperm BC habitats is already included in current assessments, so that macroalgae are de facto recognized as important donors of BC. The key challenges are (i) documenting macroalgal carbon sequestered beyond BC habitat, (ii) tracing it back to source habitats, and (iii) showing that management actions at the habitat lead to increased sequestration at the sink site. These challenges apply equally to carbon exported from BC coastal habitats. Because of the large carbon sink they support, incorporation of macroalgae into BC accounting and actions is an imperative. This requires a paradigm shift in accounting procedures as well as developing methods to enable the capacity to trace carbon from donor to sink habitats in the ocean

Food supply confers calcifiers resistance to ocean acidification

Invasion of ocean surface waters by anthropogenic CO emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification.This work was funded by grants from the Danish Environmental Protection Agency within the Danish 486 Cooperation for Environment in the Arctic (DANCEA), ASSEMBLE grant agreement no. 227799 from European Community and from the Spanish Ministry of Economy and Competitiveness (ESTRESX, number CTM2012-32603). N.A.L. acknowledges support from grants Fondecyt 1140938 and NC 1200286 (Millennium Nucleus Project MUSELS) and L.R. was supported by BECAS CHILE fellowship program from Comisión Nacional de Investigación Científica y Tecnológica de Chile (CONICYT)Peer Reviewe

Seagrass blue carbon stocks and sequestration rates in the Colombian Caribbean

Seagrass ecosystems rank amongst the most efficient natural carbon sinks on earth, sequestering CO2 through photosynthesis and storing organic carbon (Corg) underneath their soils for millennia and thereby, mitigating climate change. However, estimates of Corg stocks and accumulation rates in seagrass meadows (blue carbon) are restricted to few regions, and further information on spatial variability is required to derive robust global estimates. Here we studied soil Corg stocks and accumulation rates in seagrass meadows across the Colombian Caribbean. We estimated that Thalassia testudinum meadows store 241 ± 118 Mg Corg ha−1 (mean ± SD) in the top 1 m-thick soils, accumulated at rates of 122 ± 62 and 15 ± 7 g Corg m−2 year−1 over the last ~ 70 years and up to 2000 years, respectively. The tropical climate of the Caribbean Sea and associated sediment run-off, together with the relatively high primary production of T. testudinum, influencing biotic and abiotic drivers of Corg storage linked to seagrass and soil respiration rates, explains their relatively high Corg stocks and accumulation rates when compared to other meadows globally. Differences in soil Corg storage among Colombian Caribbean regions are largely linked to differences in the relative contribution of Corg sources to the soil Corg pool (seagrass, algae Halimeda tuna, mangrove and seston) and the content of soil particles \u3c 0.016 mm binding Corg and enhancing its preservation. Despite the moderate areal extent of T. testudinum in the Colombian Caribbean (661 km2), it sequesters around 0.3 Tg CO2 year−1, which is equivalent to ~ 0.4% of CO2 emissions from fossil fuels in Colombia. This study adds data from a new region to a growing dataset on seagrass blue carbon and further explores differences in meadow Corg storage based on biotic and abiotic environmental factors, while providing the basis for the implementation of seagrass blue carbon strategies in Colombia