La crítica y sus (in)certezas : Hacia una articulación de las teorías sociológicas de Horkheimer, Adorno y Bourdieu: teoría crítica, sociología reflexiva y sus potencialidades para una crítica del presente

La problemática a ser investigada se articula en torno al interrogante acerca de cómo elaborar una perspectiva crítica de los mecanismos de reproducción de la desigualdad social de nuestro presente, que no se asiente en un referente de certeza producto de algún tipo de fundamento normativo. Con este fin se estudiarán, centralmente, dos registros de la teoría sociológica del siglo XX: la teoría crítica de la sociedad producida por Horkheimer y Adorno, y la sociología reflexiva de P. Bourdieu. Buscando, en la tensión entre ambas, los elementos conceptuales que permitan dar cuenta del interrogante planteado. De allí que esta investigación se enfoque en la forma en que estos autores construyen sus respectivas críticas culturales, estudiando los "fundamentos metódico-conceptuales" de las mismas. Así la puesta en diálogo de las teorías sociológicas alemana y francesa será la vía por la cual hacernos de los hilos conceptuales con los que elaborar la trama de una teoría crítica de nuestro presente que no se funde en un referente de certeza. Pero que aun así sea capaz de abordar diversos materiales culturales para, a través de esa crítica cultural, aprehender los mecanismos que reproducen la forma en que la sociedad se da un orden a sí misma, la estructuración de lo político. En pos de luchar por la desarticulación de aquellas estructuras funcionales a la reproducción de las relaciones de dominación establecidas.

La crítica y sus (in)certezas : Hacia una articulación de las teorías sociológicas de Horkheimer, Adorno y Bourdieu: teoría crítica, sociología reflexiva y sus potencialidades para una crítica del presente

La problemática a ser investigada se articula en torno al interrogante acerca de cómo elaborar una perspectiva crítica de los mecanismos de reproducción de la desigualdad social de nuestro presente, que no se asiente en un referente de certeza producto de algún tipo de fundamento normativo. Con este fin se estudiarán, centralmente, dos registros de la teoría sociológica del siglo XX: la teoría crítica de la sociedad producida por Horkheimer y Adorno, y la sociología reflexiva de P. Bourdieu. Buscando, en la tensión entre ambas, los elementos conceptuales que permitan dar cuenta del interrogante planteado. De allí que esta investigación se enfoque en la forma en que estos autores construyen sus respectivas críticas culturales, estudiando los "fundamentos metódico-conceptuales" de las mismas. Así la puesta en diálogo de las teorías sociológicas alemana y francesa será la vía por la cual hacernos de los hilos conceptuales con los que elaborar la trama de una teoría crítica de nuestro presente que no se funde en un referente de certeza. Pero que aun así sea capaz de abordar diversos materiales culturales para, a través de esa crítica cultural, aprehender los mecanismos que reproducen la forma en que la sociedad se da un orden a sí misma, la estructuración de lo político. En pos de luchar por la desarticulación de aquellas estructuras funcionales a la reproducción de las relaciones de dominación establecidas.

La crítica y sus (in)certezas : Hacia una articulación de las teorías sociológicas de Horkheimer, Adorno y Bourdieu: teoría crítica, sociología reflexiva y sus potencialidades para una crítica del presente

La problemática a ser investigada se articula en torno al interrogante acerca de cómo elaborar una perspectiva crítica de los mecanismos de reproducción de la desigualdad social de nuestro presente, que no se asiente en un referente de certeza producto de algún tipo de fundamento normativo. Con este fin se estudiarán, centralmente, dos registros de la teoría sociológica del siglo XX: la teoría crítica de la sociedad producida por Horkheimer y Adorno, y la sociología reflexiva de P. Bourdieu. Buscando, en la tensión entre ambas, los elementos conceptuales que permitan dar cuenta del interrogante planteado. De allí que esta investigación se enfoque en la forma en que estos autores construyen sus respectivas críticas culturales, estudiando los "fundamentos metódico-conceptuales" de las mismas. Así la puesta en diálogo de las teorías sociológicas alemana y francesa será la vía por la cual hacernos de los hilos conceptuales con los que elaborar la trama de una teoría crítica de nuestro presente que no se funde en un referente de certeza. Pero que aun así sea capaz de abordar diversos materiales culturales para, a través de esa crítica cultural, aprehender los mecanismos que reproducen la forma en que la sociedad se da un orden a sí misma, la estructuración de lo político. En pos de luchar por la desarticulación de aquellas estructuras funcionales a la reproducción de las relaciones de dominación establecidas.

Acute survivorship of the deep-sea coral Lophelia pertusa from the Gulf of Mexico under acidification,warming,and deoxygenation

Changing global climate due to anthropogenic emissions of CO2 are driving rapid changes in the physical and chemical environment of the oceans via warming, deoxygenation, and acidification. These changes may threaten the persistence of species and populations across a range of latitudes and depths, including species that support diverse biological communities that in turn provide ecological stability and support commercial interests. Worldwide, but particularly in the North Atlantic and deep Gulf of Mexico, Lophelia pertusa forms expansive reefs that support biological communities whose diversity rivals that of tropical coral reefs. In this study, L. pertusa colonies were collected from the Viosca Knoll region in the Gulf of Mexico (390 to 450 m depth), genotyped using microsatellite markers, and exposed to a series of treatments testing survivorship responses to acidification, warming, and deoxygenation. All coral nubbins survived the acidification scenarios tested, between pH of 7.67 and 7.90 and aragonite saturation states of 0.92 and 1.47. However, calcification generally declined with respect to pH, though a disparate response was evident where select individuals net calcified and others exhibited net dissolution near a saturation state of 1. Warming and deoxygenation both had negative effects on survivorship, with up to 100% mortality observed at temperatures above 14ºC and oxygen concentrations of approximately 1.5 ml·l-1. These results suggest that, over the short-term, climate change and OA may negatively impact L. pertusa in the Gulf of Mexico, though the potential for acclimation and the effects of genetic background should be considered in future research.

Morphological plasticity of the coral skeleton under CO2-driven seawater acidification

Ocean acidification causes corals to calcify at reduced rates, but current understanding of the underlying processes is limited. Here, we conduct a mechanistic study into how seawater acidification alters skeletal growth of the coral Stylophora pistillata. Reductions in colony calcification rates are manifested as increases in skeletal porosity at lower pH, while linear extension of skeletons remains unchanged. Inspection of the microstructure of skeletons and measurements of pH at the site of calcification indicate that dissolution is not responsible for changes in skeletal porosity. Instead, changes occur by enlargement of corallite-calyxes and thinning of associated skeletal elements, constituting a modification in skeleton architecture. We also detect increases in the organic matrix protein content of skeletons formed under lower pH. Overall, our study reveals that seawater acidification not only causes decreases in calcification, but can also cause morphological change of the coral skeleton to a more porous and potentially fragile phenotype.

Decreased light availability can amplify negative impacts of ocean acidification on calcifying coral reef organisms

Coral reef organisms are increasingly and simultaneously affected by global and local stressors such as ocean acidification (OA) and reduced light availability. However, knowledge of the interplay between OA and light availability is scarce. We exposed 2 calcifying coral reef species (the scleractinian coral Acropora millepora and the green alga Halimeda opuntia) to combinations of ambient and increased pCO2 (427 and 1073 µatm, respectively), and 2 light intensities (35 and 150 µmol photons/m**2/s) for 16 d. We evaluated the individual and combined effects of these 2 stressors on weight increase, calcification rates, O2 fluxes and chlorophyll a content for the species investigated. Weight increase of A. millepora was significantly reduced by OA (48%) and low light intensity (96%) compared to controls. While OA did not affect coral calcification in the light, it decreased calcification in the dark by 155%, leading to dissolution of the skeleton. H. opuntia weight increase was not affected by OA, but decreased (40%) at low light. OA did not affect algae calcification in the light, but decreased calcification in the dark by 164%, leading to dissolution. Low light significantly reduced gross photosynthesis (56 and 57%), net photosynthesis (62 and 60%) and respiration (43 and 48%) of A. millepora and H. opuntia, respectively. In contrast to A. millepora, H. opuntia significantly increased chlorophyll content by 15% over the course of the experiment. No interactive effects of OA and low light intensity were found on any response variable for either organism. However, A. millepora exhibited additive effects of OA and low light, while H. opuntia was only affected by low light. Thus, this study suggests that negative effects of low light and OA are additive on corals, which may have implications for management of river discharge into coastal coral reefs.

Changes in coral reef communities across a natural gradient in seawater pH

Ocean acidification threatens the survival of coral reef ecosystems worldwide. The negative effects of ocean acidification observed in many laboratory experiments have been seen in studies of naturally low-pH reefs, with little evidence to date for adaptation. Recently, we reported initial data suggesting that low-pH coral communities of the Palau Rock Islands appear healthy despite the extreme conditions in which they live. Here, we build on that observation with a comprehensive statistical analysis of benthic communities across Palau's natural acidification gradient. Our analysis revealed a shift in coral community composition but no impact of acidification on coral richness, coralline algae abundance, macroalgae cover, coral calcification, or skeletal density. However, coral bioerosion increased 11-fold as pH decreased from the barrier reefs to the Rock Island bays. Indeed, a comparison of the naturally low-pH coral reef systems studied so far revealed increased bioerosion to be the only consistent feature among them, as responses varied across other indices of ecosystem health. Our results imply that whereas community responses may vary, escalation of coral reef bioerosion and acceleration of a shift from net accreting to net eroding reef structures will likely be a global signature of ocean acidification.

Seawater carbonate chemistry and zooxanthellate coral Cladocora caespitosa boron isotopic and elemental systematics during experiments, 2011

Boron isotopic and elemental systematics are used to define the vital effects for the temperate shallow water Mediterranean coral Cladocora caespitosa. The corals are from a range of seawater pH conditions (pHT ~ 7.6 to ~ 8.1) and environmental settings: (1) naturally living colonies harvested from normal pH waters offshore Levanto, (2) colonies transplanted nearby a subsea volcanic vent system, and (3) corals cultured in aquaria exposed to high (700 µatm) and near present day (400 µatm) pCO2 levels. B/Ca compositions measured using laser ablation inductively coupled mass spectrometry (LA-ICPMS) show that boron uptake by C. caespitosa cultured at different pCO2 levels is independent of ambient seawater pH being mainly controlled by temperature-dependent calcification. In contrast, the boron isotope compositions (delta11Bcarb) of the full suite of corals determined by positive thermal ionisation mass spectrometry (PTIMS) shows a clear trend of decreasing delta11Bcarb (from 26.7 to 22.2 %o) with decreasing seawater pH, reflecting the strong pH dependence of the boron isotope system. The delta11Bcarb compositions together with measurements of ambient seawater parameters enable calibration of the boron pH proxy for C. caespitosa, by using a new approach that defines the relationship between ambient seawater pH (pHsw) and the internally controlled pH at the site of calcification (pHbiol). C. caespitosa exhibits a linear relationship between pHsw and the shift in pH due to physiological processes (deltapH = pHbiol - pHsw) giving the regression deltapHClad = 4.80 - 0.52* pHsw for this species. We further apply this method ("deltapH-pHsw") to calibrate tropical species of Porites, Acropora, and Stylophora reported in the literature. The temperate and tropical species calibrations are all linearly correlated (r2 > 0.9) and the biological fractionation component (deltapH) between species varies within ~ 0.2 pH units. Our "deltapH-pHsw" approach provides a robust and accurate tool to reconstruct palaeoseawater pHsw for both temperate and tropical corals, further validating the boron fractionation factor (alphaB3-B4 = 1.0272) determined experimentally by Klochko et al. (2006) and the boron isotope pH proxy, both of which have been the foci of considerable debate.

Calcium isotope fractionation in cultured, modern and fossil scleractinian coral skeleton

The present study investigates the influence of environmental (temperature, salinity) and biological (growth rate, inter-generic variations) parameters on calcium isotope fractionation (d44/40Ca) in scleractinian coral skeleton to better constrain this record. Previous studies focused on the d44/40Ca record in different marine organisms to reconstruct seawater composition or temperature, but only few studies investigated corals. This study presents measurements performed on modern corals from natural environments (from the Maldives for modern and from Tahiti for fossil corals) as well as from laboratory cultures (Centre Scientifique de Monaco). Measurements on Porites sp., Acropora sp., Montipora verrucosa and Stylophora pistillata allow constraining inter-generic variability. Our results show that the fractionation of d44/40Ca ranges from 0.6 to 0.1 per mil, independent of the genus or the environmental conditions. No significant relationship between the rate of calcification and d44/40Ca was found. The weak temperature dependence reported in earlier studies is most probably not the only parameter that is responsible for the fractionation. Indeed, sub-seasonal temperature variations reconstructed by d18O and Sr/Ca ratio using a multi-proxy approach, are not mirrored in the coral's d44/40Ca variations. The intergeneric variability and intrageneric variability among the studied samples are weak except for S. pistillata, which shows calcium isotopic values increasing with salinity. The variability between samples cultured at a salinity of 40 is higher than those cultured at a salinity of 36 for this species. The present study reveals a strong biological control of the skeletal calcium isotope composition by the polyp and a weak influence of environmental factors, specifically temperature and salinity (except for S. pistillata). Vital effects have to be investigated in situ to better constrain their influence on the calcium isotopic signal. If vital effects could be extracted from the isotopic signal, the calcium isotopic composition of coral skeletons could provide reliable information on the calcium composition and budget in ocean.

Galápagos coral reef persistence after ENSO warming across an acidification gradient

Anthropogenic CO2 is causing warming and ocean acidification. Coral reefs are being severely impacted, yet confusion lingers regarding how reefs will respond to these stressors over this century. Since the 1982-1983 El Niño-Southern Oscillation warming event, the persistence of reefs around the Galápagos Islands has differed across an acidification gradient. Reefs disappeared where pH<8.0 and aragonite saturation state (Omega arag)<=3 and have not recovered, whereas one reef has persisted where pH>8.0 and Omega arag>3. Where upwelling is greatest, calcification by massive Porites is higher than predicted by a published relationship with temperature despite high CO2, possibly due to elevated nutrients. However, skeletal P/Ca, a proxy for phosphate exposure, negatively correlates with density (R=-0.822, p<0.0001). We propose that elevated nutrients have the potential to exacerbate acidification by depressing coral skeletal densities and further increasing bioerosion already accelerated by low pH.