Transformando la enseñanza y el aprendizaje

En el presente documento se expone el recurso material que presenta la utilización de las pizarras interactivas que "como ninguna tecnología lo había hecho antes tienen el poder de transformar la enseñanza y el aprendizaje", empleando las propias las palabras de la autora del artículo, Nancy Knowlton

Ancient DNA from coral-hosted Symbiodinium reveal a static mutualism over the last 172 years.

Ancient DNA (aDNA) provides powerful evidence for detecting the genetic basis for adaptation to environmental change in many taxa. Among the greatest of changes in our biosphere within the last century is rapid anthropogenic ocean warming. This phenomenon threatens corals with extinction, evidenced by the increasing observation of widespread mortality following mass bleaching events. There is some evidence and conjecture that coral-dinoflagellate symbioses change partnerships in response to changing external conditions over ecological and evolutionary timescales. Until now, we have been unable to ascertain the genetic identity of Symbiodinium hosted by corals prior to the rapid global change of the last century. Here, we show that Symbiodinium cells recovered from dry, century old specimens of 6 host species of octocorals contain sufficient DNA for amplification of the ITS2 subregion of the nuclear ribosomal DNA, commonly used for genotyping within this genus. Through comparisons with modern specimens sampled from similar locales we show that symbiotic associations among several species have been static over the last century, thereby suggesting that adaptive shifts to novel symbiont types is not common among these gorgonians, and perhaps, symbiotic corals in general

Discrimination of Species in the Montastrea annularis Complex using Multiple Genetic Loci

Montastraea annularis, M. franksi and M. faveolata are a complex of recently distinguished coral species whose status remains controversial due to the lack of fixed differences. Here we report on two types of genetic analyses for these taxa: 1) DNA sequences of two nuclear genes [internal transcribed spacers of rDNA (ITS-1, ITS-2) and a ɮ-tubulin intron] and 2) a preliminary screening of the entire nuclear genome using amplified fragment length polymorphisms (AFLP). There was very little variation within or among the three species in DNA sequences. Onlly 3 of 300 nucleotide positions in ITS-1, 3 of the 350 positions in ITS-2, and 3 of 350 positions in the ɮ-tubulin intron had large amounts of polymorphism. At some of these sites there were allele frequency differences among the species, but no diagnostic substitutions. Sequences from polymorphic sites in the ɮ-tubulin intron also showed evidence of heterozygosity. Pilot experiments with AFLP yielded stronger evidence of genetic boundaries among these species. Two AFLP primers gave patterns of band presence or absence that were potentially diagnostic for M. faveolata (n=7) versus M. franksi (n=7); M. annularis (n=4) may also have diagnostic patterns, but the differences between it and M. franksi were quantitative (band intensity) rather than qualitative

Genetic, Spatial, and Temporal Components of Precise Spawning Synchrony in Reef Building Corals of the Montastraea annularis Species Complex

When organisms release gametes into the sea, synchrony must be precise to increase fertilization and decrease hybridization. We tagged and genotyped over 400 spawning corals from the three species in the Montastraea annularis species complex. We report on the influence of species, individuals, and genotypes on timing of spawning from 2002 through 2009. During their annual spawning event M. franksi spawns on average 2 h after sunset, whereas M. annularis and M. faveolata spawn 3.5 h after sunset. Only M. franksi and M. annularis have compatible gametes. Individual colonies of the same genotype spawn at approximately the same time after sunset within and across years (within minutes), but different genotypes have significantly different spawning times. Neighboring colonies, regardless of genotype, spawn more synchronously than individuals spaced further apart. At a given distance, clone-mates spawn more synchronously than nonclone-mates. A transplant experiment indicates a genetic and environmental influence on spawn time. There is strong, but not absolute, concordance between spawn time, morphology, and genetics. Tight precision in spawning is achieved via a combination of external cues, genetic precision, and perhaps conspecific signaling. These mechanisms are likely to influence reproductive success and reproductive isolation in a density-dependent manner

#OceanOptimism: Balancing the Narrative About the Future of the Ocean

The ocean is facing multiple pressures from human activities, including the effects of climate change. Science has a prominent role in identifying problems and communicating these to society. However, scientists are also increasingly taking an active role in developing solutions, including strategies for adapting to and mitigating climate change, increasing food security, and reducing pollution. Transmitting these solutions to society changes our narrative about the ocean and motivates actions. The United Nations triple initiatives for this decade—the Sustainable Development Goals, the Decade on Ocean Science for Sustainable Development, and the Decade of Ecosystem Restoration—provide the momentum for this change in narrative and focus. Here, we reflect on the search for solutions and the need for better ways of communicating science in a positive way. We synthesize insights from a summer school held during the COVID-19 pandemic and present some examples of successes and failures and the lessons learned from these.#OceanOptimism: Balancing the Narrative About the Future of the OceanpublishedVersio

The Aquatic Automated Dosing and Maintenance System (AADAMS)

The maintenance and dosing of aquatic organisms, such as corals and mollusks, are essential for ecotoxicology studies, yet it is difficult to maintain many of these sensitive organisms for an extended period. Consequently, many previous aquatic ecotoxicology experiments have been limited in their number of replicates and maintained in one or a few experimental aquaria, with only a limited number of stressors tested in each experiment. Here we describe a modular system that overcomes many of the difficulties of maintaining large numbers of sensitive aquatic organisms in separate containers, and allows testing of a large suite of stressors in each experiment. The AADAMS (aquatic automated dosing and maintenance system) allows testing of 40 independent stressors with 10 independent replicates per stressor (400 individuals total). The AADAMS provides surge and regular water changes simultaneously with accurate dosing via Venturi valves. In a series of experiments over a 1-year period, the AADAMS was used to test the effects of various factors affecting water quality on Caribbean coral reefs. Roofing tar and road asphalt were two of the most damaging pollutants tested, with LD50 values (lethal dose that killed 50% of the corals) of 0.013 g L–1 and 0.079 g L–1, respectively, thus suggesting that runoff from roads and near-shore construction could be contributing to reef decline. The AADAMS is an accurate, reliable system for highly replicated ecotoxicological studies of sensitive aquatic organisms, which are important indicators of ecosystem health

Climate change promotes parasitism in a coral symbiosis.

Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals' sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodinium phylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change