29 research outputs found
Sensitivity of Calcification to Thermal Stress Varies among Genera of Massive Reef-Building Corals
Reductions in calcification in reef-building corals occur when thermal conditions are suboptimal, but it is unclear how they vary between genera in response to the same thermal stress event. Using densitometry techniques, we investigate reductions in the calcification rate of massive Porites spp. from the Great Barrier Reef (GBR), and P. astreoides, Montastraea faveolata, and M. franksi from the Mesoamerican Barrier Reef (MBR), and correlate them to thermal stress associated with ocean warming. Results show that Porites spp. are more sensitive to increasing temperature than Montastraea, with calcification rates decreasing by 0.40 g cm−2 year−1 in Porites spp. and 0.12 g cm−2 year−1 in Montastraea spp. for each 1°C increase. Under similar warming trends, the predicted calcification rates at 2100 are close to zero in Porites spp. and reduced by 40% in Montastraea spp. However, these predictions do not account for ocean acidification. Although yearly mean aragonite saturation (Ωar) at MBR sites has recently decreased, only P. astreoides at Chinchorro showed a reduction in calcification. In corals at the other sites calcification did not change, indicating there was no widespread effect of Ωar changes on coral calcification rate in the MBR. Even in the absence of ocean acidification, differential reductions in calcification between Porites spp. and Montastraea spp. associated with warming might be expected to have significant ecological repercussions. For instance, Porites spp. invest increased calcification in extension, and under warming scenarios it may reduce their ability to compete for space. As a consequence, shifts in taxonomic composition would be expected in Indo-Pacific reefs with uncertain repercussions for biodiversity. By contrast, Montastraea spp. use their increased calcification resources to construct denser skeletons. Reductions in calcification would therefore make them more susceptible to both physical and biological breakdown, seriously affecting ecosystem function in Atlantic reefs
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Responses of the tropical gorgonian coral Eunicea fusca to ocean acidification conditions
Ocean acidification can have negative repercussions from the organism to ecosystem levels. Octocorals deposit high-magnesium calcite in their skeletons, and according to different models, they could be more susceptible to the depletion of carbonate ions than either calcite or aragonite-depositing organisms. This study investigated the response of the gorgonian coral Eunicea fusca to a range of CO2 concentrations from 285 to 4,568 ppm (pH range 8.1-7.1) over a 4-week period. Gorgonian growth and calcification were measured at each level of CO2 as linear extension rate and percent change in buoyant weight and calcein incorporation in individual sclerites, respectively. There was a significant negative relationship for calcification and CO2 concentration that was well explained by a linear model regression analysis for both buoyant weight and calcein staining. In general, growth and calcification did not stop in any of the concentrations of pCO2; however, some of the octocoral fragments experienced negative calcification at undersaturated levels of calcium carbonate (>4,500 ppm) suggesting possible dissolution effects. These results highlight the susceptibility of the gorgonian coral E. fusca to elevated levels of carbon dioxide but suggest that E. fusca could still survive well in mid-term ocean acidification conditions expected by the end of this century, which provides important information on the effects of ocean acidification on the dynamics of coral reef communities. Gorgonian corals can be expected to diversify and thrive in the Atlantic-Eastern Pacific; as scleractinian corals decline, it is likely to expect a shift in these reef communities from scleractinian coral dominated to octocoral/soft coral dominated under a "business as usual" scenario of CO2 emissions
A Mentors Role in the Advancement of Black Women in and to Senior Administrator Positions
Effects of idiosyncratic stimulus variables on functional analysis outcomes.
As the methods for the functional analysis of problem behavior have continued to develop, there has been a greater focus on the specificity of controlling variables, both antecedents and consequences. Accelerating research interest in the role of antecedents reveals that a large array of stimulus variables can influence the rate of problem behavior. Indeed, the variety of these stimuli is so great that it is sometimes possible to overlook specific stimulus variables during initial assessment. The present study shows that a failure to identify these very specific (idiosyncratic) stimulus variables is serious because their presence can systematically alter the outcomes of functional analyses that are designed to assess the motivation of problem behavior. Guidelines are therefore discussed concerning when to suspect that idiosyncratic stimuli might be acting to influence assessment data, thereby promoting a search for additional stimulus variables whose identification can aid in improving the design of functional analysis conditions
Hatchery broodstock conditioning of the blue mussel Mytilus edulis (Linnaeus, 1758). Part II. New formulated feeds offer new perspectives to commercial hatcheries
Supplementary methods and results from A new terrestrial paleoenvironmental record from the Bering Land Bridge and context for human dispersal
Supplementary methods and result
Lack of relationship between psychological denial and unawareness of illness in schizophrenia-spectrum disorders
The Eye of Hartigan : A Multi-Media Exhibit of Members' Works Selected by Grace Hartigan
Hartigan comments on her experience as a juror for this show of work by 31 women artists. Artist's statements. Biographical notes