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Spatio-temporal analysis of the droughts in Cali, Colombia and their primary relationships with the El Nino-Southern Oscillation (ENSO) between 1971 and 2011
Full text linkThis paper analyzed the spatio-temporal variability of droughts in Cali, Colombia and their primary relations to the El Nino Southern Oscillation (ENSO). The Standardized Precipitation Index (SPI) was used to detect drought events from monthly rainfall data of 24 stations well spread over Cali during 1971-2011. The SPI provided the drought intensity, magnitude, frequency, and the minimum rainfall thresholds, mainly on an annual scale (SPI-12). Eighty percent of the stations reported four events with dry conditions in Cali: 1976-1977, 1983-1984, 1990-1992 and 2009-2010. The ENSO influence was evaluated using the correlation and wavelet transform analyses. Significant (non-significant) negative correlations between SPI-12 in the northern (southern) part of Cali, the multivariate ENSO Index (MEI), and Sea Surface Temperature (SST) Nino 3.4 and Nino 4 indices were observed. The wavelet coherence analysis showed significant coherencies between ENSO and SPI-12: at interannual scale (4-6 years), the phase difference of-135o generates a lag of 6-9 months between the minimum peak of the SPI-12 and the maximum peak of the indices. On the quasi-biennial scale (2-3 years), the phase difference of-180o suggests that the maximum wet (dry) conditions coincide with the mature stage of the La Nina (El Nino) event; and on the decadal scale (8-16 years), the decreases (increases) in rainfall precede the El Nino (La Nina) mature stage by approximately 10-18 months. These results are relevant for seasonal forecasting, since changes in SST in the equatorial Pacific may take place 6-18 months ahead of the dry conditions in Cali. © 2020 Universidad Nacional Autonoma de Mexico
Characterization of Amount and Quality of Tucuman Kernel Oil as a Potential Biomass
No full textAmazonian tucuman (Astrocaryum aculeatum) fruit pulp is consumed directly without heat treatment, and is appreciated in the region of Manaus, Amazonas State, Brazil. The kernel is discarded after pulp removal, resulting in costs related to waste management. This study aimed to perform an estimate on the annual amount of kernels generated by commercialization of tucuman fruit in six markets in Manaus by monthly application of questionnaires to merchants. The yield of edible pulp and kernels were assessed, as well as the yield and characteristics of kernel oil. Fruits consisted of pulp (26% fresh weight) and the coproduct is mainly pyrene (70%), comprising a hard woody endocarp (61%) and an oily kernel (39% dry weight). Kernel oil yield ranged from 28% to 45%. The generated coproducts were estimated as 272 t/y (fresh weight) and approximately 6–10 t/y of lauric oil could be obtained. The main fatty acids were lauric—12:0 (52.3–57.5%) and myristic—14:0 (23.4–27.1%), presenting a similar profile to other lauric oils such as coconut, palm kernel, and babassu oils. Oxidative stability ranged from 20 to 44 hours, which is considered high compared to other lauric oils. The recovery of this coproduct will improve the sustainability of the tucuman chain, providing a new product of Amazonian biodiversity and reducing the environmental impact. © 2020 AOC
Ascorbic acid and anthocyanins rich powders based on the encapsulation of the AmazonMyrciaria dubia fruit: effect of drying method
No full textGuide to image editing and production of figures for scientific publications with an emphasis on taxonomy
No full textFigures for scientific publications go through various stages from the planning, to the capturing of images, to the production of finished figures for publication. This guide is meant to familiarise the reader with the main image-editing software used by professional photographers. The guide's focus is on digital photo editing and the production of figures using Adobe Photoshop to produce publication-quality figures for scientific publications. This guide will be of fundamental use for the academic public, especially taxonomists and others who work with images. Besides, it should be useful for anyone interested in becoming familiar with the basic tools of image editing. © 2020
Use of the medicinal plant Bauhinia forficata Link. by carriers of type 2 diabetes mellitus: A study in the Brazilian amazon
No full textAn explanation for the isotopic offset between soil and stem water in a temperate tree species
No full textA growing number of field studies report isotopic offsets between stem water and its potential sources that prevent the unambiguous identification of plant water origin using water isotopes. We explored the causes of this isotopic offset by conducting a controlled experiment on the temperate tree species Fagus sylvatica. We measured δ2H and δ18O of soil and stem water from potted saplings growing on three soil substrates and subjected to two watering regimes. Regardless of substrate, soil and stem water δ2H were similar only near permanent wilting point. Under moister conditions, stem water δ2H was 11 ± 3‰ more negative than soil water δ2H, coherent with field studies. Under drier conditions, stem water δ2H became progressively more enriched than soil water δ2H. Although stem water δ18O broadly reflected that of soil water, soil–stem δ2H and δ18O differences were correlated (r = 0.76) and increased with transpiration rates indicated by proxies. Soil–stem isotopic offsets are more likely to be caused by water isotope heterogeneities within the soil pore and stem tissues, which would be masked under drier conditions as a result of evaporative enrichment, than by fractionation under root water uptake. Our results challenge our current understanding of isotopic signals in the soil–plant continuum. © 2020 The Authors. New Phytologist © 2020 New Phytologist Trus
Palms and trees resist extreme drought in Amazon forests with shallow water tables
No full textThe intensity and frequency of severe droughts in the Amazon region have increased in the recent decades. These extreme events are associated with changes in forest dynamics, biomass and floristic composition. However, most studies of drought response have focused on upland forests with deep water tables, which may be especially sensitive to drought. Palms, which tend to dominate the less well-drained soils, have also been neglected. The relative neglect of shallow water tables and palms is a significant concern for our understanding of tropical drought impacts, especially as one-third of Amazon forests grow on shallow water tables (<5 m deep). We evaluated the drought response of palms and trees in forests distributed over a 600 km transect in central-southern Amazonia, where the landscape is dominated by shallow water table forests (SWTF). We compared vegetation dynamics before and following the 2015–2016 El Nino drought, the hottest and driest on record for the region (−214 mm of cumulative water deficit). We observed no change in stand mortality rates and no biomass loss in response to drought in these forests. Instead, we observed an increase in recruitment rates, which doubled to 6.78% year-1 ± 4.40 (M ± SD) during 2015–2016 for palms and increased by half for trees (to 2.92% year-1 ± 1.21), compared to rates in the pre-El-Nino interval. Within these SWTF, mortality and recruitment rates varied as a function of climatic drought intensity and water table depth for both palms and trees, with mortality being greatest in climatically and hydrologically wetter environments and recruitment greatest in drier environments. Across our transect, there was a significant increase over time in tree biomass. Synthesis. Our results indicate that forests growing over shallow water tables—relatively under-studied vegetation that nonetheless occupies one-third of Amazon forests—are remarkably resistant to drought. These findings are consistent with the hypothesis that local hydrology and its interactions with climate strongly constrain forest drought effects, and has implications for climate change feedbacks. This work enhances our understanding of integrated drought effects on tropical forest dynamics and highlights the importance of incorporating neglected forest types into both the modelling of forest climate responses and into public decisions about priorities for conservation. © 2020 British Ecological Societ
Fungicidal properties and insights on the mechanisms of the action of volatile oils from Amazonian Aniba trees
Full text linkThe Amazonian Aniba species are world-renowned for their essential oils (EOs). The molecules derived from EOs have been intensively investigated in regards to their potential for disease control in plants. The aim of this study was to investigate the antifungal properties of Aniba canelilla EO (ACEO) and Aniba parviflora EO (APEO) when used against eight phytopathogenic fungi. Gas chromatography-mass spectrometry (GC–MS) analysis of oils showed that 1-nitro-2-phenylethane (∼80%) and linalool (∼40%) are the major compounds in ACEO and APEO, respectively. The ACEO and APEO treatments displayed remarkable antifungal effects against Aspergillus flavus, Aspergillus niger, Fusarium oxysporum, Fusarium solani, Alternaria alternata, Colletotrichum gloeosporioides, Colletotrichum musae and Colletotrichum guaranicola, for which the IC50 values ranged from 0.05 to 0.28 μL mL−1 and 0.17 to 0.63 μL mL−1, respectively. Furthermore, the oil caused the inhibition of conidial germination by at least 83% for ACEO and 78% for APEO. The ACEO and APEO at 5 μL mL−1 induced leakage of nucleic acids and protein, suggesting that inhibition could be linked to the breakdown of membrane integrity of the conidia. In addition, the detection of fluorescent dye propidium iodide (PI) on F. solani conidia treated with ACEO and APEO indicates damage on the conidia cytoplasmic membrane. The findings of this study may be of biotechnological interest for the development of new plant protection products, with the advantage of being less harmful than the agrochemicals currently available. © 2019 Elsevier B.V
Genetic diversity and dynamics of repetitive DNA elements of exotic fish introduced into the Brazilian Amazon region
No full textLitter accumulation and biomass dynamics in riparian zones in tropical South America of the Asian invasive plant Hedychium coronarium J. König (Zingiberaceae)
No full textBackground: Promoting changes in abiotic conditions and ecosystem processes, such as decomposition, is a mechanism by which some exotic plant species displace native plants and become invasive. Aims: We monitored ramets of Hedychium coronarium over 30 months to estimate the litter decay rate, biomass dynamics and litter accumulation over time in riparian sites invaded by the species in southeastern Brazil. Methods: We measured the number, height, emergence and mortality of ramets in three environments invaded by H. coronarium (natural, rural and urban). We also measured litter decay in situ and in in vitro experiments. We used sinusoidal models to describe height fluctuation and exponential models to simulate litter decay and litter accumulation. Results: Ramets of H. coronarium showed high seasonal variation in terms of height and emergence, as well as low litter decay. Accordingly, our models predicted high litter production and a seasonal pattern of litter accumulation in invaded sites. Conclusions: H. coronarium produces a great amount of litter, which shows slow decay and hence seems to affect decomposition processes. Investigating seasonal variation on the effects of invasive species on ecosystem functioning shed light on the factors driving the success and impact of invasive plants. © 2019, © 2019 Botanical Society of Scotland and Taylor & Francis