849 research outputs found

    Determination of kinetic parameters for the torrefaction of coconut endocarp –Acrocomia aculeata– in the temperature range 230–320 °C

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    "The purpose of this study was to determine kinetic parameters for models commonly used for lignocellulosic biomass and evaluate different types of kinetic models proposed in the literature."CONACYT - Consejo Nacional de Ciencias y TecnologíaPROCIENCI

    Shipping traffic through the Arctic Ocean: Spatial distribution, seasonal variation, and its dependence on the sea ice extent

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    The reduction in sea ice cover with Arctic warming facilitates shipping through remarkably shorter shipping routes. Automatic identification system (AIS) is a powerful data source to monitor Arctic Ocean shipping. Based on the AIS data from an online platform, we quantified the spatial distribution of shipping through this area, its intensity, and the seasonal variation. Shipping was heterogeneously distributed with power-law exponents that depended on the vessel category. We contextualized the estimated exponents with the analytical distribution of a transit model in one and two dimensions. Fishing vessels had the largest spatial spread, while narrower shipping routes associated with cargo and tanker vessels had a width correlated with the sea ice area. The time evolution of these routes showed extended periods of shipping activity through the year. We used AIS data to quantify recent Arctic shipping, which brings an opportunity for shorter routes, but likely impacting the Arctic ecosystem. © 2024J.P.R. was supported by Juan de la Cierva Formacion program (Ref. FJC2019-040622-I) funded by MCIN/AEI/10.13039/501100011033, and by the Vicen\u00E7 Mut program from Govern de les Illes Balears. J.P.R. received support from Spanish Research Agency MCIN/AEI/10.13039/501100011033 via project MISLAND (PID2020-114324GB-C22). This research is supported by Mar\u00EDa de Maeztu Excellence Unit 2023-2027 (Refs. CEX2021-001201-M and CEX2021-001164-M) funded by MCIN/AEI/10.13039/501100011033. The authors acknowledge the platform HUB Ocean (hubocean.earth) for access to the data and the computational facilities to remotely run all the analyses, through the Ocean Data Connector. J.P.R.: conceptualization, data curation, formal analysis (leading), software, visualization, and writing \u2013 original draft. K.K.: formal analysis and writing \u2013 review and editing. C.M.D.: conceptualization and writing \u2013 review and editing. V.M.E.: conceptualization, formal analysis (supporting), and writing \u2013 original draft. The authors declare no competing interests. J.P.R. was supported by Juan de la Cierva Formacion program (Ref. FJC2019-040622-I ) funded by MCIN/AEI/10.13039/501100011033 , and by the Vicen\u00E7 Mut program from Govern de les Illes Balears. J.P.R. received support from Spanish Research Agency MCIN/AEI/10.13039/501100011033 via project MISLAND ( PID2020-114324GB-C22 )

    Use of European pulses to produce functional beverages – From chickpea and lupin as dairy alternatives

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    Consumption of plant based products as dairy alternatives is increasing steeply. This diet transition can only be achieved if these products keep the nutritional value and meet consumer’s sensory acceptance. This work aimed to evaluate the decrease of the “beany” flavour and of raffinose, stachyose and verbascose contents in EU pulse beveragés production, and also the best lactic fermentation conditions of the beverages, towards chickpea- and lupin-based yoghurts, with rheology properties similar to the commercial soy yoghurts. The reduction of “beany” volatile compounds of chickpea and lupin beverages during processing was confirmed through GC–MS analysis. Soaking and cooking processes were effective in removing flatulence sugars with almost 48% loss from the initial content in lupin beverage. The fermentation conditions at 40 ◦C, 12 h and 2% (w/v) of starter concentration evidenced the best viscoelastic structure and flow properties. The lupin yoghurt-type showed a similar gel structure to commercial soy yoghurt.info:eu-repo/semantics/publishedVersio

    Assessment of Red Sea temperatures in CMIP5 models for present and future climate

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    The increase of the temperature in the Red Sea basin due to global warming could have a large negative effect on its marine ecosystem. Consequently, there is a growing interest, from the scientific community and public organizations, in obtaining reliable projections of the Red Sea temperatures throughout the 21st century. However, the main tool used to do climate projections, the global climate models (GCM), may not be well suited for that relatively small region. In this work we assess the skills of the CMIP5 ensemble of GCMs in reproducing different aspects of the Red Sea 3D temperature variability. The results suggest that some of the GCMs are able to reproduce the present variability at large spatial scales with accuracy comparable to medium and high-resolution hindcasts. In general, the skills of the GCMs are better inside the Red Sea than outside, in the Gulf of Aden. Based on their performance, 8 of the original ensemble of 43 GCMs have been selected to project the temperature evolution of the basin. Bearing in mind the GCM limitations, this can be an useful benchmark once the high resolution projections are available. Those models project an averaged warming at the end of the century (2080–2100) of 3.3 ±> 0.6°C and 1.6 ±> 0.4°C at the surface under the scenarios RCP8.5 and RCP4.5, respectively. In the deeper layers the warming is projected to be smaller, reaching 2.2 ±> 0.5°C and 1.5 ±> 0.3°C at 300 m. The projected warming will largely overcome the natural multidecadal variability, which could induce temporary and moderate decrease of the temperatures but not enough to fully counteract it. We have also estimated how the rise of the mean temperature could modify the characteristics of the marine heatwaves in the region. The results show that the average length of the heatwaves would increase ~15 times and the intensity of the heatwaves ~4 times with respect to the present conditions under the scenario RCP8.5 (10 time and 3.6 times, respectively, under scenario RCP4.5).En prensa4,41

    Bacterial and microeukaryotic plankton communities in a semi-intensive aquaculture system of sea bass (Dicentrarchus labrax): a seasonal survey

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    The importance of microbial diversity and their role in the maintenance of fish health in aquaculture systems has been increasingly recognized in recent years. However, there is still a major knowledge gap regarding the ecology, composition and dynamics of microbial plankton assemblages during fish production. In this study, we aimed to investigate the seasonal dynamics and potential interactions of bacterial and microeukaryotic plankton communities in a semi-intensive aquaculture for European sea bass (Dicentrarchus labrax) cultured together with low density of gilthead sea bream (Sparus aurata) over a one-year period (January/2014 – November/2014). While the most abundant bacterial classes were Gammaproteobacteria, Flavobacteriia and Alphaproteobacteria; microeukaryotic communities were dominated by Ochrophyta, Chlorophyta and Ciliophora groups. Temperature and salinity were identified as significant drivers of the overall microbial community composition, which varied congruently along the seasons. However, while the dominant (more abundant) groups of bacteria occurred in the warmest months, the dominant groups of microeukaryotes occurred in the coldest months. There was also an inverse relationship between abundances of grazers and bacterial operational taxonomic units (OTUs). Overall, besides the potential effects of the abiotic parameters on the microbial plankton communities, the correlation between bacteria and microeukaryotic populations observed here may be an indication of trophic and/or metabolic interdependence between these two domains. Future studies should focus on the underlying mechanisms of this interdependence for a better understand of the impact of microeukaryotic communities on aquaculture bacterioplankton structure and function. In addition, this knowledge could be of interest in the development of microbial management strategies for aquaculture systems.publishe

    Macroalgae contribute to nested mosaics of pH variability in a subarctic fjord

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    The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification, and large-scale assessments of pH and the saturation state for aragonite (O<sub>arag</sub>) have led to the notion that the Arctic Ocean is already close to a corrosive state. In high-latitude coastal waters the regulation of pH and O<sub>arag</sub> is, however, far more complex than offshore because increased biological activity and input of glacial meltwater affect pH. Effects of ocean acidification on calcifiers and non-calcifying phototrophs occupying coastal habitats cannot be derived from extrapolation of current and forecasted offshore conditions, but they require an understanding of the regimes of pH and O<sub>arag</sub> in their coastal habitats. To increase knowledge of the natural variability in pH in the Arctic coastal zone and specifically to test the influence of benthic vegetated habitats, we quantified pH variability in a Greenland fjord in a nested-scale approach. A sensor array logging pH, O<sub>2</sub>, PAR, temperature and salinity was applied on spatial scales ranging from kilometre scale across the horizontal extension of the fjord; to 100 m scale vertically in the fjord, 10–100 m scale between subtidal habitats with and without kelp forests and between vegetated tidal pools and adjacent vegetated shores; and to centimetre to metre scale within kelp forests and millimetre scale across diffusive boundary layers of macrophyte tissue. In addition, we assessed the temporal variability in pH on diurnal and seasonal scales. Based on pH measurements combined with point samples of total alkalinity, dissolved inorganic carbon and relationships to salinity, we also estimated variability in O<sub>arag</sub>. Results show variability in pH and O<sub>arag</sub> of up to 0.2–0.3 units at several scales, i.e. along the horizontal and vertical extension of the fjord, between seasons and on a diel basis in benthic habitats and within 1 m<sup>3</sup> of kelp forest. Vegetated intertidal pools exhibited extreme diel pH variability of &gt; 1.5 units and macrophyte diffusive boundary layers a pH range of up to 0.8 units. Overall, pelagic and benthic metabolism was an important driver of pH and O<sub>arag</sub> producing mosaics of variability from low levels in the dark to peak levels at high irradiance generally appearing favourable for calcification. We suggest that productive coastal environments may form niches of high pH in a future acidified Arctic Ocean

    Gestão da água e das águas residuais para uma viticultura e enologia sustentáveis no sul de Portugal - Revisão

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    Assessing sustainability of the wine industry requires improved characterization of its environmental impacts, namely in terms of water use. Therefore, quantification of water inputs and wastewater (WW) outputs is needed to highlight inefficiencies in wine production and related consequences for the environment. Water use and WW generation in irrigated viticulture and oenology remains insufficiently quantified for dry Mediterranean regions (e.g. South Portugal). This paper is focused on wine production under warm and dry climate conditions in the winegrowing region of Alentejo (South Portugal). This region experiences increasingly dry conditions, while the irrigated area keeps expanding, which puts exacerbates the pressure on existing local and regional water resources. Additionally, more erratic variation in climate conditions and the tendency for increasingly extreme climate events (e.g. heat waves) pose more challenges to Alentejo’s wine sector. We conclude that quantitative information on water use and management is not always easy to obtain or access, which hinders improved strategies and/or policies for water use at farm, winery and region-level. Up-to-date statistics and robust metrics can help to better characterize water use and WW flows for Alentejo’s wine region, while optimizing management in vineyards and wineries, in companies and region-wide. The paper is focused on a “Farm-Winery" scenario, which is the most common in South Portugal's wine sectorA avaliação da sustentabilidade da indústria vitivinícola requer uma caracterização detalhada do seu impacto ambiental, nomeadamente ao nível do factor água. A quantificação detalhada dos consumos de água e das águas residuais produzidas (WW) é crucial para identificação de ineficiências na indústria da vinha e do vinho. A utilização da água e a gestão dos efluentes em viticultura regada e na adega permanecem pouco quantificados nas regiões mediterrânicas. O presente trabalho centra-se na produção de vinho em condições de clima quente e seco, tomando como exemplo a região vitivinícola do Alentejo (Sul de Portugal). A região está sujeita a situações de seca mais frequentes e severas, enquanto a área regada continua em expansão, o que pressiona os recursos hídricos locais e regionais. Além disso, as condições climáticas altamente variáveis e a maior tendência para eventos climáticos extremos (e.g. ondas de calor) colocam desafios ao setor vitivinícola no Sul de Portugal. Concluímos que a informação quantitativa relativa ao uso e gestão de água não está sempre facilmente disponível, limitando a otimização de estratégias e/ou políticas para o uso da água ao nível da vinha, da adega e da região. Dados atualizados e indicadores robustos podem ajudar a caracterizar melhor o uso de água e a geração de água residual na região vitivinícola do Alentejo, otimizando a gestão na vinha e na adega, ao nível da empresa e da região. O artigo centra-se num cenário de produtor-engarrafador (“Farm-Winery”), que é o mais comum no setor vitivinícola no Sul de Portugalinfo:eu-repo/semantics/publishedVersio

    Whole-system metabolism and CO<sub>2</sub> fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean)

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    The relationship between whole-system metabolism estimates based on planktonic and benthic incubations (bare sediments and seagrass, Posidonia oceanica meadows), and CO2 fluxes across the air-sea interface were examined in the Bay of Palma (Mallorca, Spain) during two cruises in March and June 2002. Moreover, planktonic and benthic incubations were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the bay. From the annual study, results showed a contrast between the planktonic compartment, which was heterotrophic during most of the year, except for occasional bloom episodes, and the benthic compartment, which was slightly autotrophic. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the excess respiration of the planktonic compartment in shallow waters (<10 m) relative to the maximum depth of the bay (55 m). This generated a horizontal gradient from autotrophic or balanced communities in the shallow, seagrass-covered areas of the bay, to strongly heterotrophic communities in deeper areas, consistent with the patterns of CO2 fields and fluxes across the bay observed during the two extensive cruises in 2002. Finally, dissolved inorganic carbon and oxygen budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow

    Evidence for surface organic matter modulation of air-sea CO2 gas exchange

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    Air-sea CO2 exchange depends on the air-sea CO2 gradient and the gas transfer velocity (k), computed as a function of wind speed. Large discrepancies among relationships predicting k from wind suggest that other processes also contribute significantly to modulate CO2 exchange. Here we report, on the basis of the relationship between the measured gas transfer velocity and the organic carbon concentration at the ocean surface, a significant role of surface organic matter in suppressing air-sea gas exchange, at low and intermediate winds, in the open ocean, confirming previous observations. The potential role of total surface organic matter concentration (TOC) on gas transfer velocity (k) was evaluated by direct measurements of air-sea CO2 fluxes at different wind speeds and locations in the open ocean. According to the results obtained, high surface organic matter contents may lead to lower air-sea CO2 fluxes, for a given air-sea CO2 partial pressure gradient and wind speed below 5 m s−1, compared to that observed at low organic matter contents. We found the bias in calculated gas fluxes resulting from neglecting TOC to co-vary geographically and seasonally with marine productivity. These results support previous evidences that consideration of the role of organic matter in modulating air-sea CO2 exchange may improve flux estimates and help avoid possible bias associated to variability in surface organic concentration across the ocean
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