Lead and Zinc contamination of surface sediments in the main harbours of the Galician Rias

The concentration ranges and degree of contamination of lead and zinc in the four principal harbour areas of the northwest Iberian Peninsula have been defined from 130 surface sediment samples (A partir de la fracción fina en 130 muestras de sedimento superficial se han cuantificado los niveles de concentración para plomo y cinc en las rías donde se encuentran los principales puertos de la costa gallega. Los patrones de distribución de Pb y Zn en el sedimento muestran altos contenidos en el litoral próximo a las áreas de actividad portuaria y astilleros: las concentraciones llegan hasta 140, 160, 160 y 320 mg·kg-1 para Pb y hasta 150, 380, 600 y 1960 mg·kg-1 para Zn en Pontevedra, Coruña, Ferrol y Vigo, respectivamente. En base a sus niveles naturales, establecidos mediante cuatro testigos de sedimento, se han definido sus grados de contaminación mediante factores de enriquecimiento. Consecuentemente, se puede definir entre moderada y considerable la contaminación de Pb y Zn en los puertos de La Coruña y Pontevedra, así como severa en Ferrol y Vigo. En otras zonas de las rías la contaminación normalmente decrece, como suele ocurrir en estuarios y costas de nuestro planeta donde existen puertos o astilleros

Cadmium, manganese, nickel and lead contents in surface sediments of the lower Ulla River and its estuary (northwest Spain)

The authors determined the total contents of cadmium, manganese, nickel and lead in 16 surface sediment samples along the last 7 km of the Ulla River and in its estuary. Prior to chemical analysis, the grain-size fractions below 500, 63 and 2 μm were separated. The metal concentrations were analysed in the fraction below 63 μm, and in selected samples from the clay fraction ( 2 μm). The soil samples were digested with a HF + HNO₃ + HCl mixture and the total concentrations of Cd, Mn, Ni and Pb were analysed with the AAS method. The highest contents of metals were found in the riverine sediments, near the town of Padrón, and in the estuary. The enrichment of metals in the sediments was mainly related to the proximity of the industrial sources, and to the fine particles transported and deposited in the sediments. The Ni and Mn contents found are considered very high, at some points reaching values of up to 357 mg kg⁻¹ and 2 110 mg kg⁻¹, respectively. Lead and Cd were mainly found within the range considered as natural background levels in the sediments of the Galician rias, with concentrations of 25-68 mg kg⁻¹ for Pb and 0.01-0.92 mg kg⁻¹ for Cd. The lower part of the Ulla River and its estuary present: l) moderate to high contamination levels of Mn and Ni; 2) moderate Pb pollution levels; and 3) no Cd contamination. The highest concentrations of metals were obtained in the river, near the wastewater discharges, and in the estuary, associated with fine particles.El contenido total de cadmio, manganeso, níquel y plomo se determinó en 16 muestras de sedimentos superficiales a lo largo de los últimos 7 km del río Ulla y en su estuario. Previamente a los análisis químicos, se realizó la separación granulométrica de los sedimentos en las fracciones inferiores a 500, 63 y 2 μm. La concentración de metales se determinó en la fracción inferior a 63 μm y, para algunas muestras, en la fracción arcilla ( 2 μm). La digestión del sedimento se realizó en una mezcla ácida de HF + HNO₃ + HCl y se analizó la concentración total de Cd, Mn, Ni y Pb por espectroscopia de absorción atómica. Los contenidos más altos en metales se encontraron en los sedimentos del río, en las inmediaciones de Padrón y en los del estuario. El enriquecimiento de los sedimentos en metales se ha relacionado con la proximidad a las zonas industriales y con el material fino transportado y depositado en los sedimentos. Se han encontrado contenidos muy altos de Ni y Mn con valores de 357 mg kg⁻¹ y 2 110 mg kg⁻¹, respectivamente. Las concentraciones de Cd y Pb son comparables a los valores establecidos como niveles naturales en los sedimentos de las rías gallegas: 25-68 mg kg⁻¹ para el Pb y 0.01-0.92 mg kg⁻¹ para el Cd. El sedimento de la parte baja del río Ulla y su estuario presentan niveles moderados-altos de contaminación para Mn y Ni, moderados para Pb y nulos para Cd. Las mayores concentraciones de estos metales en el sedimento fueron medidas asociadas con las fracciones finas ( 63 μm): cerca de Padrón, zona de influencia fluvial y, también, aunque con valores más bajos, en la desembocadura del Ulla, zona de influencia marina.Instituto Español de Oceanografí

Chitosan encapsulation modulates the effect of capsaicin on the tight junctions of MDCK cells

Capsaicin has known pharmacological effects including the ability to reversibly open cellular tight junctions, among others. The aim of this study was to develop a strategy to enhance the paracellular transport of a substance with low permeability (FITC-dextran) across an epithelial cell monolayer via reversible opening of cellular tight junctions using a nanosystem comprised by capsaicin and of chitosan. We compared the biophysical properties of free capsaicin and capsaicin-loaded chitosan nanocapsules, including their cytotoxicity towards epithelial MDCK-C7 cells and their effect on the integrity of tight junctions, membrane permeability and cellular uptake. The cytotoxic response of MDCK-C7 cells to capsaicin at a concentration of 500 μM, which was evident for the free compound, is not observable following its encapsulation. The interaction between nanocapsules and the tight junctions of MDCK-C7 cells was investigated by impedance spectroscopy, digital holographic microscopy and structured illumination fluorescence microscopy. The nanocapsules modulated the interaction between capsaicin and tight junctions as shown by the different time profile of trans-epithelial electrical resistance and the enhanced permeability of monolayers incubated with FITC-dextran. Structured illumination fluorescence microscopy showed that the nanocapsules were internalized by MDCK-C7 cells. The capsaicin-loaded nanocapsules could be further developed as drug nanocarriers with enhanced epithelial permeability

Hydrological Variability In Chilean Altiplano Lakes during the Last Millennia

Peer Reviewe

Nanoencapsulated capsaicin changes migration behavior and morphology of madin darby canine kidney cell monolayers

We have developed a drug delivery nanosystem based on chitosan and capsaicin. Both substances have a wide range of biological activities. We investigated the nanosystem’s influence on migration and morphology of Madin Darby canine kidney (MDCK-C7) epithelial cells in comparison to the capsaicin-free nanoformulation, free capsaicin, and control cells. For minimally-invasive quantification of cell migration, we applied label-free digital holographic microscopy (DHM) and single-cell tracking. Moreover, quantitative DHM phase images were used as novel stain-free assay to quantify the temporal course of global cellular morphology changes in confluent cell layers. Cytoskeleton alterations and tight junction protein redistributions were complementary analyzed by fluorescence microscopy. Calcium influx measurements were conducted to characterize the influence of the nanoformulations and capsaicin on ion channel activities. We found that both, capsaicin-loaded and unloaded chitosan nanocapsules, and also free capsaicin, have a significant impact on directed cell migration and cellular motility. Increase of velocity and directionality of cell migration correlates with changes in the cell layer surface roughness, tight junction integrity and cytoskeleton alterations. Calcium influx into cells occurred only after nanoformulation treatment but not upon addition of free capsaicin. Our results pave the way for further studies on the biological significance of these findings and potential biomedical applications, e.g. as drug and gene carriers

Volcanism and climate change as drivers in Holocene depositional dynamic of Laguna del Maule (Andes of central Chile – 36° S)

Late Quaternary volcanic basins are active landscapes from which detailed archives of past climate and seismic and volcanic activity can be obtained. A multidisciplinary study performed on a transect of sediment cores was used to reconstruct the depositional evolution of the high-elevation Laguna del Maule (LdM) (36∘ S, 2180 m a.s.l., Chilean Andes). The recovered 5 m composite sediment sequence includes two thick turbidite units (LT1 and LT2) and numerous tephra layers (23 ash and 6 lapilli). We produced an age model based on nine new 14C AMS dates, existing 210Pb and 137Cs data, and the Quizapú ash horizon (1932 CE). According to this age model, the relatively drier Early Holocene was followed by a phase of increased productivity during the mid-Holocene and higher lake levels after 4.0 ka cal BP. Major hydroclimate transitions occurred at ca. 11, 8.0, 4.0 and 0.5 ka cal BP. Decreased summer insolation and winter precipitation due to a southward shift in the southern westerly winds and a strengthened Pacific Subtropical High could explain Early Holocene lower lake levels. Increased biological productivity during the mid-Holocene (∼8.0 to 6.0 ka cal BP) is coeval with a warm–dry phase described for much of southern South America. Periods of higher lake productivity are synchronous to a higher frequency of volcanic events. During the Late Holocene, the tephra layers show compositional changes suggesting a transition from silica-rich to silica-poor magmas at around 4.0 ka cal BP. This transition was synchronous with increased variability of sedimentary facies and geochemical proxies, indicating higher lake levels and increased moisture at LdM after 4.0 ka cal BP, most likely caused by the inception of current El Niño–Southern Oscillation and Pacific Decadal Oscillation (ENSO–PDO) dynamics in central Chile.Postprin

The national inventory of geological heritage: methodological approach and results

A existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios, realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.The existence of a national inventory of the geological heritage is of paramount importance for the implementation of a geoconservation strategy. This paper presents the methodological approach used to produce the most complete geosites inventory in Portugal, so far, and the obtained results. This inventory will be uploaded into the National Database of Natural Heritage managed by the Portuguese authority for nature conservation.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio

Climate change facilitated the early colonization of the Azores Archipelago during medieval times

Humans have made such dramatic and permanent changes to Earth's landscapes that much of it is now substantially and irreversibly altered from its preanthropogenic state. Remote islands, until recently isolated from humans, offer insights into how these landscapes evolved in response to human-induced perturbations. However, little is known about when and how remote systems were colonized because archaeological data and historical records are scarce and incomplete. Here, we use a multiproxy approach to reconstruct the initial colonization and subsequent environmental impacts on the Azores Archipelago. Our reconstructions provide unambiguous evidence for widespread human disturbance of this archipelago starting between 700 -60/+50 and 850 -60/+60 Common Era (CE), ca. 700 y earlier than historical records suggest the onset of Portuguese settlement of the islands. Settlement proceeded in three phases, during which human pressure on the terrestrial and aquatic ecosystems grew steadily (i.e., through livestock introductions, logging, and fire), resulting in irreversible changes. Our climate models suggest that the initial colonization at the end of the early Middle Ages (500 to 900 CE) occurred in conjunction with anomalous northeasterly winds and warmer Northern Hemisphere temperatures. These climate conditions likelyinhibited exploration from southern Europe and facilitated human settlers from the northeast Atlantic. These results are consistent with recent archaeological and genetic data suggesting that the Norse were most likely the earliest settlers on the islands

Stoichiometry of the degradation of dissolved and particulate biogenic organic matter in the NW Iberian upwelling

The average composition of the dissolved and particulate products of early degradation of marine phytoplankton has been established for the first time in a coastal upwelling system using a mixing analysis along isopycnal surfaces combined with a stoichiometric model. About 17–18% of the mineralized organic matter is derived from the decomposition of organic particulates, and 16–35% is from the dissolved organic matter. The remaining 50–70% is derived probably from large fast sinking particles. On average, the mineralized material on large particles has the closest composition to the Redfield formula. The ratio of dissolved saccharides to dissolved organic matter respiration is >40% higher than expected from a material of Redfield composition. Finally, the ratio of lipid to particulate organic matter respiration is >80% larger than expected from a material of Redfield composition. Regarding the decomposition of hard structures, biogenic silica dissolves predominantly in the inner shelf, where organic carbon oxidation is more intense, and diatom deposition occurs preferentially

Unusual circulation patterns of the rias baixas induced by minho freshwater intrusion (NW of the Iberian Peninsula)

The Minho River, situated 30 km south of the Rias Baixas, is the most important freshwater source flowing into the Western Galician coast (NW of the Iberian Peninsula). The buoyancy generated by the Minho estuarine plume can reverse the normal circulation pattern inside the Rias Baixas affecting the exchange between the Rias and the ocean, changing the input of nutrients. Nevertheless, this inversion of the circulation patterns is not a well-monitored phenomenon. The only published results based on in situ data related to the presence of the Minho River plume inside the Rias de Vigo and Pontevedra correspond to an event measured on spring 1998. In this case unexpectedly higher inflow surface current velocities were found at the Ria de Pontevedra, located further away from Minho River. Thus, the main aim of this study is to research the main factors inducing this unusual pattern on the circulation of the Rias de Vigo and Pontevedra. A numerical model implementation of MOHID previously developed, calibrated, and validated for this coastal area was used. Several scenarios were performed in order to explain the individual effect of the Minho River, rivers discharging into each Rias, and estuarine morphology changes. According to the model results, the Minho River discharge is a key factor in the establishment of the negative circulation, while small rivers inside the Rias slightly attenuate this circulation. The negative circulation was stronger in Ria de Pontevedra independently of the distance of this coastal system from the Minho River mouth, showing that morphologic estuarine features are the main factor justifying the different local circulation patterns