A través del espejo: una aproximación a la percepción social del pasado prehistórico desde una perspectiva de género

The media is a system of immediate and effective communication, which forms a mass culture made up of symbols, myths and stereotypes of individuals as a form of «industrialised production of reality». Within the conceptual framework of Public Archaeology, from a critical and feminist perspective, an essay is presented to approach the social perception of the prehistoric past in contemporary Popular Culture. The purpose of this work is to analyse and conceptualise the messages and ideas generated by the mass culture around the representation of prehistoric humanity to understand how they are constructed and what kind of society they promote. To this end, the image of the cavewoman is approached from its configuration in the popular imaginary to analyse the stereotypes and sexisms installed, their origin, their repercussions on the social perception of prehistory and what role this idea plays in contemporary society, and more particularly, what implications they have for women. We must go through this distorted mirror and image of the past, created by the consumer society projecting its own, where the image of women is not only that of the past but also that of the futureLos medios de comunicación son un sistema de comunicación inmediata y efectiva, que forman una cultura de masas constituida por símbolos, mitos y estereotipos de los individuos como una forma de «producción industrializada de la realidad». Dentro del marco conceptual de la Arqueología Pública, desde una perspectiva crítica y feminista, se presenta un ensayo de aproximación a la percepción social del pasado prehistórico en el ámbito de la Cultura Popular contemporánea. El propósito de este trabajo es analizar y conceptualizar los mensajes e ideas generados por la cultura de masas alrededor de la representación de la humanidad prehistórica para entender cómo se construyen y qué tipo de sociedad promueven. Para ello, se aborda la imagen de la cavewoman desde su configuración en el imaginario popular para analizar los estereotipos y sexismos instalados, su origen, su repercusión en la percepción social de la Prehistoria y qué papel juega esta idea en la sociedad contemporánea, y más particularmente, qué implicaciones tienen para las mujeres. Debemos, atravesar este espejo distorsionado e imagen del pasado, creada por la sociedad de consumo proyectando la suya propia, donde la imagen de la mujer no es sólo la del pasado, sino también la del futuro

Editorial: Marine N2 Fixation: Recent Discoveries and Future Challenges

International audienceUnicellular nitrogen fixing cyanobacteria (UCYN) are abundant members of phytoplankton communities in a wide range of marine environments, including those with rapidly changing nitrogen (N) concentrations. We hypothesized that differences in N availability (N 2 vs. combined N) would cause UCYN to shift strategies of intracellular N and C allocation. We used transmission electron microscopy and nanoscale secondary ion mass spectrometry imaging to track assimilation and intracellular allocation of 13 C-labeled CO 2 and 15 N-labeled N 2 or NO 3 at different periods across a diel cycle in Cyanothece sp. ATCC 51142. We present new ideas on interpreting these imaging data, including the influences of pre-incubation cellular C and N contents and turnover rates of inclusion bodies. Within cultures growing diazotrophically, distinct subpopulations were detected that fixed N 2 at night or in the morning. Additional significant within-population heterogeneity was likely caused by differences in the relative amounts of N assimilated into cyanophycin from sources external and internal to the cells. Whether growing on N 2 or NO 3 , cells prioritized cyanophycin synthesis when N assimilation rates were highest. N assimilation in cells growing on NO 3 switched from cyanophycin synthesis to protein synthesis, suggesting that once a cyanophycin quota is met, it is bypassed in favor of protein synthesis. Growth on NO 3 also revealed that at night, there is a very low level of CO 2 assimilation into polysaccharides simultaneous with their catabolism for protein synthesis. This study revealed multiple, detailed mechanisms underlying C and N management in Cyanothece that facilitate its success in dynamic aquatic environments

Abundance and distribution of invertebrate larvae in the Bellingshausen Sea (West Antarctica)

The central part of the Bellingshausen Sea has been poorly studied, partly because of the presence of ice during most of the year. The main aim of this study was to analyse the abundance and distribution of meroplankton, and the influence of oceanographic properties were investigated in the Bellingshausen Sea (West Antarctica) during the BENTART-06 cruise carried out in January–February 2006. Zooplankton samples were collected with a 80-μm mesh plankton net hauled vertically from a depth of 200 m to the surface at fifteen stations across the Bellingshausen Sea. Fifteen types of larval benthic invertebrates were found, with echinospira and nudibranch veligers being the most abundant. Hierarchical analysis and non-metric multidimensional scaling revealed a high degree of spatial variability in both larval abundance and larval types across the Bellingshausen Sea. The variability was significantly correlated with total chlorophyll-a and the contribution of large (>5 μm) phytoplankton to total chlorophyll, indicating the availability of food as an important factor determining the larval distribution observed. Nudibranch veligers, nemertean pilidia, echinoderm and planula larvae were more abundant at stations in the central Bellingshausen Sea, which was characterized by low phytoplankton biomass and production. Higher abundances of echinospira veligers and polychaete larvae were found at the more productive stations close to Peter I Island and the Antarctic Peninsula. The abundance and diversity of larval types found in the Bellingshausen Sea during the BENTART-06 cruise support the hypothesis that indirect development through larval swimming stages plays a key role in benthic recruitment in polar areas.Ministerio de Ciencia y Tecnología; CGL2004-0185

Crossing the Mirror: an Approach to the Social Perception of the Prehistoric Past from a Gender Perspective

The media is a system of immediate and effective communication, which forms a mass culture made up of symbols, myths and stereotypes of individuals as a form of «industrialised production of reality». Within the conceptual framework of Public Archaeology, from a critical and feminist perspective, an essay is presented to approach the social perception of the prehistoric past in contemporary Popular Culture. The purpose of this work is to analyse and conceptualise the messages and ideas generated by the mass culture around the representation of prehistoric humanity to understand how they are constructed and what kind of society they promote. To this end, the image of the cavewoman is approached from its configuration in the popular imaginary to analyse the stereotypes and sexisms installed, their origin, their repercussions on the social perception of prehistory and what role this idea plays in contemporary society, and more particularly, what implications they have for women. We must go through this distorted mirror and image of the past, created by the consumer society projecting its own, where the image of women is not only that of the past but also that of the future.Los medios de comunicación son un sistema de comunicación inmediata y efectiva, que forman una cultura de masas constituida por símbolos, mitos y estereotipos de los individuos como una forma de «producción industrializada de la realidad». Dentro del marco conceptual de la Arqueología Pública, desde una perspectiva crítica y feminista, se presenta un ensayo de aproximación a la percepción social del pasado prehistórico en el ámbito de la Cultura Popular contemporánea. El propósito de este trabajo es analizar y conceptualizar los mensajes e ideas generados por la cultura de masas alrededor de la representación de la humanidad prehistórica para entender cómo se construyen y qué tipo de sociedad promueven. Para ello, se aborda la imagen de la cavewoman desde su configuración en el imaginario popular para analizar los estereotipos y sexismos instalados, su origen, su repercusión en la percepción social de la Prehistoria y qué papel juega esta idea en la sociedad contemporánea, y más particularmente, qué implicaciones tienen para las mujeres. Debemos, atravesar este espejo distorsionado e imagen del pasado, creada por la sociedad de consumo proyectando la suya propia, donde la imagen de la mujer no es sólo la del pasado, sino también la del futuro

Nutrient limitation suppresses the temperature dependence of phytoplankton metabolic rates

Climate warming has the potential to alter ecosystem function through temperature-dependent changes in individual metabolic rates. The temperature sensitivity of phytoplankton metabolism is especially relevant, since these microorganisms sustain marine food webs and are major drivers of biogeochemical cycling. Phytoplankton metabolic rates increase with temperature when nutrients are abundant, but it is unknown if the same pattern applies under nutrient-limited growth conditions, which prevail over most of the ocean. Here we use continuous cultures of three cosmopolitan and biogeochemically relevant species (Synechococcus sp., Skeletonema costatum and Emiliania huxleyi) to determine the temperature dependence (activation energy, Ea) of metabolism under different degrees of nitrogen (N) limitation. We show that both CO2 fixation and respiration rates increase with N supply but are largely insensitive to temperature. Ea of photosynthesis (0.11 ± 0.06 eV, mean ± SE) and respiration (0.04 ± 0.17 eV) under N-limited growth is significantly smaller than Ea of growth rate under nutrient-replete conditions (0.77 ± 0.06 eV). The reduced temperature dependence of metabolic rates under nutrient limitation can be explained in terms of enzyme kinetics, because both maximum reaction rates and half-saturation constants increase with temperature. Our results suggest that the direct, stimulating effect of rising temperatures upon phytoplankton metabolic rates will be circumscribed to ecosystems with high-nutrient availabilityMinisterio de Economía y Competitividad | Ref. CTM2014-53582-

Fine scale physical-biological interactions during a shift from relaxation to upwelling with a focus on Dinophysis acuminata and its potential ciliate prey

Wind reversals and quick transitions from relaxation to upwelling in coastal areas cause major changes in water column structure, phytoplankton distribution and dominance, and rates of physiological processes. The cruise "ASIMUTH-Rías" (17–21 June 2013) was carried out in the Galician Rías and adjacent shelf, at the time of a DSP outbreak, to study small-scale physical processes associated with late spring blooms of "D. acuminata" and accompanying microzooplanktonic ciliates with the overall objective of improving predictive models of their occurrence. The cruise coincided with the initiation of an upwelling pulse following relaxation and deepening of a previously formed thin layer of diatoms. A 36-h cell cycle study carried on 18–20 June showed the vertical excursions of the thin layer, mainly delimited by the 13.5–14 °C isotherms and turbulence levels (ε) of 10−8–10−6 m2 s −3, as well as marked changes in phytoplankton composition (increased density and dominance of diatoms). There was no evidence of daily vertical migration of D. acuminata, which remained in the top layer during the cycle study, but the opposite was observed in the ciliate populations. Dinophysis and its potential prey (Mesodinium species) cell maxima overlapped after midday, when the ciliate moved to the surface, suggesting an “ambush” strategy of Dinophysis to catch prey. A remarkable decline (from 0.65 to 0.33 d−1) in division rates (µ) of D. acuminata was associated with increased turbulence (ε 2°C in about 8 h). In contrast, high division rates (µmin ∼ 0.69 d−1) persisted at a mid-shelf station where environmental conditions below the mixed layer were more stable. The onset of upwelling pulses appears to have a double negative effect on the net growth of Dinophysis populations: a direct physical effect due to advective dispersion and an indirect effect, decreased division rates. The latter would be caused by the rapid cooling of the mixed layer, and the increased turbulence at the surface resulting in shear stress to the cells. The short-term impact of upwelling pulses (and the winds promoting it) on the physiology of "Dinophysis" and its ciliate prey, and the role of mid-shelf populations of "Dinophysis" as a relatively undisturbed reservoir for the inoculation of subsequent blooms are discussed.European Commission | Ref. EC FP7-SPACE-2010-1, n. 261860Ministerio de Economía | Ref. CTM2016-75451-C2-2-RInterreg Atlantic Area | Ref. EAPA_182/2016Comisión Nacional de Ciencia y Tecnología Research (CONICYT), Chile | Ref. PAI79160065Comisión Nacional de Ciencia y Tecnología Research (CONICYT), Chile | Ref. REDES17010

Temporal variability of diazotroph community composition in the upwelling region off NW Iberia.

Knowledge of the ecology of N2-fixing (diazotrophic) plankton is mainly limited to oligotrophic (sub)tropical oceans. However, diazotrophs are widely distributed and active throughout the global ocean. Likewise, relatively little is known about the temporal dynamics of diazotrophs in productive areas. Between February 2014 and December 2015, we carried out 9 one-day samplings in the temperate northwestern Iberian upwelling system to investigate the temporal and vertical variability of the diazotrophic community and its relationship with hydrodynamic forcing. In downwelling conditions, characterized by deeper mixed layers and a homogeneous water column, non-cyanobacterial diazotrophs belonging mainly to nifH clusters 1G (Gammaproteobacteria) and 3 (putative anaerobes) dominated the diazotrophic community. In upwelling and relaxation conditions, affected by enhanced vertical stratification and hydrographic variability, the community was more heterogeneous vertically but less diverse, with prevalence of UCYN-A (unicellular cyanobacteria, subcluster 1B) and non-cyanobacterial diazotrophs from clusters 1G and 3. Oligotyping analysis of UCYN-A phylotype showed that UCYN-A2 sublineage was the most abundant (74%), followed by UCYN-A1 (23%) and UCYN-A4 (2%). UCYN-A1 oligotypes exhibited relatively low frequencies during the three hydrographic conditions, whereas UCYN-A2 showed higher abundances during upwelling and relaxation. Our findings show the presence of a diverse and temporally variable diazotrophic community driven by hydrodynamic forcing in an upwelling system

High sensitivity of ultra-oligotrophic marine ecosystems to atmospheric nitrogen deposition

Using a model of plankton and organic-matter cycling we demonstrate that variable stoichiometric ratios can lead to a more than 5-fold higher sensitivity of simulated carbon export to atmospheric N deposition in the ultra-oligotrophic eastern part of the North Atlantic subtropical gyre compared to the westerly oligotrophic region near Bermuda, often used as a reference site for subtropical regions. Stronger nutrient limitation in the ultra-oligotrophic east causes higher phytoplankton C:N ratios and lower carbon assimilation efficiency of zooplankton in the model, which results in a higher export efficiency of carbon to the deep ocean compared to the less nutrient-limited western site. Our results indicate that previous estimates of oceanic carbon uptake associated with atmospheric nitrogen deposition may not be fully robust and that spatial variability in nutrient stress and ecological stoichiometry could significantly affect the biogeochemical impact of increasing atmospheric deposition of anthropogenic nitrogen

Thermohaline structure, ageostrophic vertical velocity fields and phytoplankton distribution and production in the northeast Atlantic subtropical front

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C04020, doi:10.1029/2003JC001990.Two oceanographic cruises were carried out in the Azores Current/Subtropical Front region in July 1997 and April 1999 to study the seasonal and mesoscale spatial variability in the relationship between the hydrodynamic characteristics of the water column and the distribution of nutrients, phytoplankton biomass, and production. Both the magnitude of chlorophyll-a values and primary production rates as well as their vertical distribution varied sharply associated with subtle changes in seasonal thermal stratification. Successive upwelling and downwelling regions were detected along the track of a cyclonic meander, with maximum ageostrophic vertical velocities of 3 m d−1 and −4 m d−1, respectively, at 375 dbar. Relatively high nitrate concentrations (>3.5 μM) were found associated with denser waters at the center of the meander, where the deep chlorophyll maximum (DCM) uplifted ~20 dbar. Chlorophyll-a concentrations ranged from 0.1 to 0.4 mg m−3, with slightly higher values (>0.35 mg m−3) at the northern side of the current. A significant relationship was not detected between the vertical ageostrophic velocity field and nitrate and chlorophyll-a distributions, which were significantly correlated with the depth of the 16°C isotherm. Vertical advective fluxes of nitrate across the base of the DCM were about 2 orders of magnitude higher than vertical diffusive nitrate transport (−6.6 to 3.7 mmol m−2 d−1 versus 0.01 to 0.07 mmol m−2 d−1). Diffusive nitrate fluxes only account for <10% of the total primary production rates measured in the region.This study was funded by the European Commission under the CANIGO contract MAS3CT960060 and CICYT. B. Mourin˜o was supported by a FPU fellowship from the Ministerio de Educacio´n y Cultura (Spain)

Nitrogen inputs influence on biomass and trophic structure of ocean plankton: a study using biomass and stable isotope size-spectra.

Large scale patterns in planktonic food web structure were studied by applying continuous size-scaled models of biomass and δ15N to plankton samples, collected at 145 stations during the Malaspina-2010 Expedition across three ocean basins and including major biomes. Carbon biomass and δ15N were determined in size-fractionated samples (40 to 5000 μm) collected by vertical hauls (0-200 m). Biomass-normalized size-spectra were constructed to summarize food web structure and spatial patterns in spectral parameters were analyzed using geographically-weighted regression analysis. Except in the northwestern Atlantic, size-spectra showed low variability, reflecting a large homogeneity in nitrogen sources and food web structure for the central oceans. Estimated predator-to-prey mass ratios 20% (Trades and Westerlies biomes) suggested that oceanic plankton food webs could support a larger number of trophic levels than current estimates based on high efficiency values. The largest changes in spectral parameters and nitrogen sources were related to inputs of atmospheric nitrogen, either from diazotrophic organisms or dust deposition. These results suggest geographic homogeneity in the net transfer of nitrogen up the food web.CONSOLIDER-INGENIO 2010 (CSD2008-00077) ; EURO-BASIN (FP7-ENV-2010 264933)Preprint1,749