Universidad de Magallanes
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Still Arctic?-The changing Barents Sea
No full textThe Barents Sea is one of the Polar regions where current climate and ecosystem change is most pronounced. Here we review the current state of knowledge of the physical, chemical and biological systems in the Barents Sea. Physical conditions in this area are characterized by large seasonal contrasts between partial sea-ice cover in winter and spring versus predominantly open water in summer and autumn. Observations over recent decades show that surface air and ocean temperatures have increased, sea-ice extent has decreased, ocean stratification has weakened, and water chemistry and ecosystem components have changed, the latter in a direction often described as "Atlantification" or "borealisation," with a less "Arctic" appearance. Temporal and spatial changes in the Barents Sea have a wider relevance, both in the context of large-scale climatic (air, water mass and sea-ice) transport processes and in comparison to other Arctic regions. These observed changes also have socioeconomic consequences, including for fisheries and other human activities. While several of the ongoing changes are monitored and quantified, observation and knowledge gaps remain, especially for winter months when field observations and sample collections are still sparse. Knowledge of the interplay of physical and biogeochemical drivers and ecosystem responses, including complex feedback processes, needs further development
Glacial geomorphology between the Gran Campo Nevado and Estrecho de Magallanes, Chile (52-53°S, 73°W)
No full textWe present the first extensive high-resolution glacial geomorphic map west of the Andean Cordillera in southernmost Chile (52.8-53.1 degrees S, 73.0-73.9 degrees W). The map extends over 1565 km(2) and is based on high-resolution satellite images and aerial photographs. At selected locations, the remotely mapped geomorphology was corroborated by field observations. The study area is dominated by glacial erosional landforms (77%) over depositional landforms (23%), with published submarine depositional landforms having been included (e.g. moraines). Glacial drift, kettle kame topography and lateral and frontal moraines form the primary depositional landforms and sediment associations. Glacial cirques, wide U-shaped valleys, whalebacks, roches moutonnees and scoured bedrock characterize most of the mapped area. The spatial distribution of whalebacks and roches moutonnees in the study area indicates a lack of lithological control on their formation and a warm-based, dynamic ice velocity and thickness regime during Patagonian Ice Sheet cover and retreat during the last glacial cycle
Surface shortwave cloud radiative effect of cumulus and stratocumulus-cumulus cloud types in the Caribbean area (Camagüey Cuba, 2010-2016)
No full textABSTRACT The effects of cumulus (Cu) clouds and the combination of stratocumulus-cumulus (Sc-Cu) clouds on solar radiation at the Earth's surface were evaluated at Camagüey, Cuba, during a 6-yr period (from June 2010 to May 2016). Two methods to calculate the cloud radiative effect (CRE) were employed. The first method (CREm) uses solar irradiances in cloudy conditions from actinometric observations, where cloud information was also reported by visual observation. In the second method (CRE0) surface solar irradiances were estimated for both cloudy and clear sky conditions using a 1-D radiative transfer model, and cloud optical depth (COD) retrieved from an AERONET sun-photometer as the main input. A temporal correspondence criterion between COD retrievals and actinometric observations was performed in order to classify the COD of each cloud type. After the application of this criterion, the COD belonging to the optically thin clouds was removed. Finally, 255 and 732 COD observations for Cu and Sc-Cu, respectively, were found. Results show a statistically significant difference at the 95% confidence level between CRE calculated for Sc-Cu and Cu, using both methods. Mean values of CREm and CRE0 for Cu (Sc-Cu) were −442 (−390) and −460 (−417) Wm-2, respectively. CRE0 shows a linear relation with ln(COD), with stronger correlation at a lower solar zenith angle. The shortwave cloud effect efficiency (CEE) for the two cloud types sharply decreases with the increase of the COD value up to 20. For larger COD, the CEE is less sensitive to the increase of COD
Chemogenetic inhibition of NTS astrocytes normalizes cardiac autonomic control and ameliorate hypertension during chronic intermittent hypoxia
No full textBackgroundObstructive sleep apnea (OSA) is characterized by recurrent episodes of chronic intermittent hypoxia (CIH), which has been linked to the development of sympathoexcitation and hypertension. Furthermore, it has been shown that CIH induced inflammation and neuronal hyperactivation in the nucleus of the solitary tract (NTS), a key brainstem region involved in sympathetic and cardiovascular regulation. Since several studies have proposed that NTS astrocytes may mediate neuroinflammation, we aimed to determine the potential contribution of NTS-astrocytes on the pathogenesis of CIH-induced hypertension.ResultsTwenty-one days of CIH induced autonomic imbalance and hypertension in rats. Notably, acute chemogenetic inhibition (CNO) of medullary NTS astrocytes using Designer Receptors Exclusively Activated by Designers Drugs (DREADD) restored normal cardiac variability (LF/HF: 1.1 +/- 0.2 vs. 2.4 +/- 0.2 vs. 1.4 +/- 0.3, Sham vs. CIH vs. CIH + CNO, respectively) and markedly reduced arterial blood pressure in rats exposed to CIH (MABP: 82.7 +/- 1.2 vs. 104.8 +/- 4.4 vs. 89.6 +/- 0.9 mmHg, Sham vs. CIH vs. CIH + CNO, respectively). In addition, the potentiated sympathoexcitation elicit by acute hypoxic chemoreflex activation in rats exposed to CIH was also completely abolished by chemogenetic inhibition of NTS astrocytes using DREADDs.ConclusionOur results support a role for NTS astrocytes in the maintenance of heightened sympathetic drive and hypertension during chronic exposure to intermittent hypoxia mimicking OSA
Overweight and obesity in schoolchildren in the Magallanes and Chilean Antarctica Region, Chile, (2009-2019), and comparison of two methodologies for diagnosis.
No full textIntroduction. In Chile the prevalence of total obesity in school population reaches 31% and severe obesity 10.8%. The Magallanes and Chilean Antarctica Region is one of the most affected by this epidemic. Reliable nutritional diagnosis and timely intervention can prevent children from getting sick and deteriorating their quality of life. Objective. To analyze the trend of nutritional status of schoolchildren in the Magallanes Region, according to data reported by the National Board of School Aid and Scholarships, JUNAEB between 2009-2019 and compare results from 2010 with our own study. Materials and methods. The nutritional status of 71,334 schoolchildren in the Magallanes Region and Chilean Antarctica was analyzed by educational level and demographic variables, according to information from JUNAEB. Then, the results of schoolchildren in 1st grade in 2010 were compared, obtained through two methods: secondary source, JUNAEB survey, and primary source, anthropometric study carried out in the same region and year. Results. According to JUNAEB data, overweight increased in school children in the region by 4.4% between 2009 and 2019, the most affected group was 1st grade. In 2010 the prevalence of obesity for 1st grade schoolchildren according to JUNAEB was 21.8% and according to our own regional study it was 25.7%. Conclusions. Excess malnutrition affects 53.8% of school children in the Magallanes Region and could be higher, considering that census information could be underestimating overweight and obesity. It is urgent to intervene to avoid perpetuating this epidemic
The perceived happiness in older women and their relationship with social support, well-being, social functioning, and physical health
No full textEl presente estudio busca conocer la relación y correlación entre diversos factores psicosociales y la percepción de felicidad en mujeres mayores, de edad consolidada. Se realizó un estudio transversal correlacional. Un total de 115 participantes contestaron cuestionarios midiendo felicidad, apoyo social percibido, bienestar psicológico, funcionamiento social y salud general. Los resultados centrales indican que las participantes más felices, perciben poseer mayor apoyo social, mejor bienestar psicológico, mayor autonomía y se implican más en actividades sociales y de interés personal. En términos de su salud general, solo se observaron diferencias en el caso de la vitalidad y el dolor. Sin embargo, esta última variable fue la única que resultó explicativa de la felicidad, indicando que la afecta de forma importante y negativa. Se discuten los resultados en torno a la importancia de la ausencia del dolor como factor determinante que permite que otras variables psicológicas y sociales aporten a la felicidad percibida en población añosa
A revision of the higher latitude periwinkle species Laevilitorina caliginosa sensu lato
No full textThe marine gastropod genus Laevilitorina is exclusive to the Southern Hemisphere, with 21 species from southern South America, Antarctica, Australia, New Zealand, and sub-Antarctic Islands. We present a comprehensive revision of Laevilitorina, using molecular and morphological analyses, to address formally the interspecific divergences within the nominal taxon Laevilitorina caliginosa s.l. We confirm the validity of L. caliginosa and Laevilitorina venusta, and we demonstrate that specimens from the Strait of Magellan and Hornos Island constitute four new species here described: Laevilitorina magellanica sp. nov., Laevilitorina pepita sp. nov., Laevilitorina fueguina sp. nov., and Laevilitorina hicana sp. nov. All six species are clearly distinguishable genetically, morphologically, and through radular tooth shape and configurations. Laevilitorina venusta is broadly distributed across the Antarctic Peninsula, South Georgia, and sub-Antarctic Islands (Marion, Crozet, Kerguelen, and Macquarie), whereas L. caliginosa s.s. appears geographically restricted to Cape Horn, the Falkland/Malvinas Islands, and South Georgia. The identification of populations from Macquarie Island as L. caliginosa is dubious; we suggest that these records are likely to pertain to L. venusta. This detailed revision of Laevilitorina, whereby hidden diversity was detected, significantly enriches our knowledge of the evolutionary history of this group
Peaty wetlands of the Nahuelbuta National Park (Araucanía Region), compared with others in a latitudinal Chilean gradient Humedales turbosos del Parque Nacional Nahuelbuta (Región de la Araucanía) comparados con otros, en un gradiente latitudinal de Chile
No full textPeat bogs are wetlands characterized as swamps of very extreme cold and wet places. In Chile there are several types of them: sphagnum bogs (minerotrophic), pulvinated bogs (ombrotrophic), grassy bogs, shrubby bogs and wooded bogs. This work was carried out in the peat bogs of the northern limit of them areal, in Nahuelbuta National Park, located in the Cordillera de la Costa approximately 1200 to 2300 m above sea level between the Regions of Bío-Bío and Araucanía, Chile. The flora was studied with traditional methods and the vegetation with phytosociological methodology and the results were confirmed with multivariate classification and ordination statistics. The vascular, moss and lichenic flora showed little floristic richness, only 38 species. All the flora species are native and six of them are endemic. This flora gives rise to four new peaty plant associations for Chile: two pulvinate-bogs (Myrteolo-Donatietum fasciculariae and Gaultherio-Oreoboletum obtusangulae), one sphagnum-bogs (Carici-Sphagnetum magellanicii) and one grassy-bogs (Bacharido-Festucetum scabriusculae). When comparing the peat bogs studied with those further south, the donatia pulvinate-bogs appear to be more homogeneous than the sphagnum peat bogs, in fact, the former share five species and the latter, only two. In general, a greater variation of the pulvinated peat bogs was found in the Aysén Region and of the sphagnum bogs in the Chiloé Region, the latter coming out of the conglomerate formed by the other four places. It was confirmed that in both latitudinal extremes the peat bogs are poorer in species and the greatest richness occurs in the intermediate regions
Biocultural Conservation In Biosphere Reserves In Temperate Regions Of Chile, Estonia, Germany, And Sweden
No full textUNESCO Biosphere Reserves are protected areas aiming to reconcile conservation with human well-being. In 2021, there are 714 biosphere reserves worldwide located in a variety of biomes. However, in the temperate south of South America, between latitudes 45 and 60°S, there are only three biosphere reserves. Among them, the Cape Horn Biosphere Reserve (CHBR, 55°S) in southernmost Chile implements a biocultural conservation approach. In contrast, in Europe, at latitudes 45–60°N, there are 70 biosphere reserves in different biophysical, cultural, and institutional-socio-political contexts. Our study compares approaches to biocultural education and conservation of the CHBR with three European biosphere reserves. We found exemplary conservation initiatives in biosphere reserves in Estonia, Germany, and Sweden, which have similarities with their southern equivalent.
First, in all these reserves education approaches focus on underperceived and under-valued biota, particularly small organisms. Second, research includes an important education component. Third, conservation actions take place giving consideration for cultural aspects.
From our case studies, we derive three lessons: (1) holistic conservation can be achieved, even in the absence of great funding schemes, when approaches are simple, integrative, and locally centered; (2) countries highly committed to the biosphere reserve concept more widely implement local innovation for sustainable activities; and (3) similar biomes have similar conservation challenges. This highlights the necessity to establish partnerships among biosphere reserves located in similar biomes
(Paleo)glacier studies in Patagonia over the past decades (1976-2020): A bibliometric perspective based on the Web of Science
No full textPatagonia features the most extensive glaciers of the Southern Hemisphere, excluding Antarctica, and a vast inventory of glacial landforms, so it is thought to have played a key role in (paleo)glacier studies since the late 19th century. However, no systematic attempts to characterize the specific research trends and the scientific community focused on Patagonian cryosphere have been conducted so far. To fill this gap, we analyzed the metadata associated to 305 articles compiled from the Web of Science database following a bibliometric approach covering the period between 1976 and 2020. Our results point to an irregular but net increase on the number of contributions on Patagonian (paleo)glaciers. Mass balance analyses based on satellite data of presentday glaciers and the reconstruction of past glacier activity by dating glacial landforms formed during the Last Glacial Termination, were the most addressed topics during the analyzed period. Patagonian (paleo)glacier studies are mostly published in generic Earth Sciences publications, followed by Quaternary and glaciological journals. Most of the studies were led by scientists from the United Kingdom, followed by Chile, Argentina and United States. In terms of collaborations, these studies can be divided into two main clusters, one composed by researchers from United States, Chile and Argentina institutions, and another mostly composed by British researchers. So far, the most prolific authors are nearly equally distributed in nationality, yet gender inclusion and international collaborations are still caveats that must be solved. Even though our query on the Web of Science missed highly influential (so-called) grey literature, such as local scientific journals and technical reports, the reviewed scientific literature unambiguously indicates that Patagonia is a privileged location for (paleo)glaciers studies worldwide and that it will continue offering vast opportunities to tackle critical questions related to global cryosphere and past-to-present climate changes