Dust and tropical PMx aerosols in Cape Verde: Sources, vertical distributions and stratified transport from North Africa
We investigated the sources and processes affecting the vertical distribution of tropical PMx aerosols (particulate matter -PM- smaller than 10, 2.5 and 1 μm, PM10, PM2.5 and PM1, respectively) in the low troposphere of Santo Antão and São Vicente islands, in Cape Verde archipelago, a region where a better understanding of aerosols is needed due to their involvement in tropical meteorology and their impact on air quality, ocean and climate. We found that local sources had a low-scale impact. From transect measurements at ground level, we found that PMx levels were predominantly low, except near to PMx sources, where distinctive PM1 / PM2.5 ratios were measured, linked to vehicle exhaust (0.96), biomass burning (0.67) and Cape Verdean dust (0.36) emissions. The depth of the marine boundary layer (MBL) and the vertical distributions of PMx showed wide variability prompted by meteorological conditions. The trade winds prevailed in the MBL, whereas other airflows were situated above it: North-Atlantic, African easterly airflow and Saharan Air Layer. Under North-Atlantic airflow conditions, the MBL extended to 1400 m above sea level (m.a.s.l.). Above this altitude, PMx concentrations decreased quickly (< 3 μg/m3) due to the free troposphere conditions. Under Saharan dust conditions, the MBL was confined to just 70 m.a.s.l., whereas a complex dust stratification was observed above, characterized by alternating dry air layers with high dust loads (PM10 ~ 100 μg/m3) and more humid air layers with lower aerosol loads (PM10 ~ 40 μg/m3). Within the dry easterly African airflow occurring above the marine stratocumulus typical of the MBL top (placed at 500 m.a.s.l.), we detected layers enriched in hydrophilic aerosols (PM10: ~ 8 μg/m3). These were imbedded in relatively humid air (RH ~48%), probably linked to secondary aerosol formation by in-cloud processes in the marine stratocumulus situated below. We found that PMx transport from North Africa, both under dust and dust-free conditions, is associated with complex vertical stratifications, even within the dusty Saharan Air Layer.
Rodríguez, Sergio; López-Darias, Jessica
Litosetoenins A–E, Diterpenoids from the Soft Coral Litophyton setoensis, Backbone-Rearranged through Divergent Cyclization Achieved by Epoxide Reactivity Inversion
|Litosetoenins A–E (1–5), five new ring-rearranged serrulatane-type diterpenoids with a common tricyclo[3.0.4]decane core, along with a known diterpenoid glycoside (6), a related known diterpenoid (7), and four known sesquiterpenoids (8–11), were isolated from a Balinese soft coral Litophyton setoensis. Spirolitosetoenin A (5a) and isospirolitosetoenin A (5b), featuring an unprecedented spiro[4,5]decane core, were obtained after treatment of compound 5 with HCl in methanol. The structures of new compounds were elucidated by extensive spectroscopic analysis, quantum mechanical nuclear magnetic resonance approach, and chemical methods. A plausible biosynthetic pathway involving an unusual divergent biogenesis was proposed.|
Li, Song-Wei; Mudianta, I. Wayan; Cuadrado, Cristina; Geng, Li; Yudasmara, Gede A.; Setiabudi, Gede I. ;Hernández Daranas, Antonio; Guo, Yue-Wei
A unified model of species abundance, genetic diversity, and functional diversity reveals the mechanisms structuring ecological communities
Biodiversity accumulates hierarchically by means of ecological and evolutionary processes and feedbacks. Within ecological communities drift, dispersal, speciation, and selection operate simultaneously to shape patterns of biodiversity. Reconciling the relative importance of these is hindered by current models and inference methods, which tend to focus on a subset of processes and their resulting predictions. Here we introduce Massive Eco-evolutionary Synthesis Simulations (MESS), a unified mechanistic model of community assembly, rooted in classic island biogeography theory, which makes temporally explicit joint predictions across three biodiversity data axes: i) species richness and abundances; ii) population genetic diversities; and iii) trait variation in a phylogenetic context. Using simulations we demonstrate that each data axis captures information at different timescales, and that integrating these axes enables discriminating among previously unidentifiable community assembly models. MESS is unique in generating predictions of community-scale genetic diversity, and in characterizing joint patterns of genetic diversity, abundance, and trait values. MESS unlocks the full potential for investigation of biodiversity processes using multi-dimensional community data including a genetic component, such as might be produced by contemporary eDNA or metabarcoding studies. We combine with supervised machine learning to fit the parameters of the model to real data and infer processes underlying how biodiversity accumulates, using communities of tropical trees, arthropods, and gastropods as case studies that span a range of data availability scenarios, and spatial and taxonomic scales.
Overcast, Isaac; Ruffley, Megan; Rosindell, James; Harmon, Luke ; Borges, Paulo A. V.; Emerson, Brent C.; Etienne, Rampal S.; Gillespie, Rosemary; Krehenwinkel, Henrik; Mahler, D. Luke; Massol, Francois; Parent, Christine E.; Patiño, Jairo; Peter, Ben; Week, Bob; Wagner, Catherine; Hickerson, Michael J.; Rominger, Andrew
Macroclimatic structuring of spatial phylogenetic turnover in liverworts
Phylogenetic turnover has emerged as a powerful tool to identify the mechanisms by which biological communities assemble. When significantly structured along environmental gradients, phylogenetic turnover evidences phylogenetic niche conservatism, a critical principle explaining patterns of species distributions at different spatio–temporal scales. Here, we quantify the contribution of geographic and macroclimatic drivers to explain patterns of phylogenetic turnover in an entire phylum of land plants, namely liverworts. We further determine whether climatic niche conservatism has constrained the distribution of liverworts in the course of their evolutionary history. Two datasets, one insular, focused on 60 archipelagos and including 2346 species, and the second global, including 6334 species in 451 oceanic and continental operational geographic units (OGUs) worldwide, were assembled. Phylogenetic turnover among OGUs was quantified through πst statistics. πst-through-time profiles were generated at 1 Myr intervals along the phylogenetic time-scale and used to compute the correlation between πst, current geographic distance and macroclimatic variation with Mantel tests based on Moran spectral randomization to control for spatial autocorrelation. The contribution of macroclimatic variation to phylogenetic turnover was about four-times higher than that of geographic distance, a pattern that was consistently observed in island and global geographic settings, and with datasets including or excluding species-poor OGUs. The correlation between phylogenetic turnover and geographic distance rapidly decayed at increasing phylogenetic depth, whereas the relationship with macroclimatic variation remained constant until 100 Mya. Our analyses reveal that changes in the phylogenetic composition among liverwort floras across the globe are primarily shaped by macroclimatic variation. They demonstrate the relevance of macroclimatic niche conservatism for the assembly of liverwort floras over very large spatial and evolutionary time scales, which may explain why such a pervasive biodiversity pattern as the increase of species richness towards the tropics also applies to organisms with high dispersal capacities.
Collart, Flavien; Wang, Jian ;Patiño, Jairo; Hagborg, Anders; Söderström, Lars; Goffinet, Bernard; Magain, Nicolas; Hardy, Olivier J.; Vanderpoorten, Alain
Trophic strategies of two sympatric endemic pigeons in insular ecosystems: a framework for understanding spatiotemporal frugivory interactions
Pigeons are considered to play key ecological roles in frugivory and seed dispersal. They have colonised numerous oceanic islands and diversified into several species in sympatry. How these species coexist in similar niches is poorly understood although dietary separation is among the mechanisms suggested to avoid trophic overlap. We investigated the trophic ecology of the two endemic Columba species co-occurring in the laurel forest and thermosclerophyllous relicts of two of the Canary Islands. This study includes diet description in spatiotemporal terms, its relationship with fruit availability and seed treatment in 10 study areas established on La Palma and La Gomera. We used non-invasive DNA analysis to identify the faeces of the two con-generic species and microhistological methods to examine their diets. The degree of trophic overlap was evaluated by niche similarity and breadth indices. Molecular faecal sampling determined the spatiotemporal distribution of both pigeons to identify their areas of coexistence. These frugivorous pigeons’ diets did not differ concerning the main plant species, but they diverged quantitatively in the proportions and parts of plants consumed. Lauraceae fruits were their staple foods although Rhamnaceae and some Fabaceae and Solanaceae were also important. Both pigeons showed selective preferences for some fruits. Significant spatiotemporal variations in their diets were observed along with a general tendency to increase fruit intake at its ripening times. Our results suggest that different trophic strategies facilitate the coexistence of these frugivorous columbids. These pigeons act as seed dispersers and/or predators depend ing on seed features (size and hardness), and this may have valuable implications for their conservation.
Marrero, Patricia; Nogales, Manuel
Coming of age for COI metabarcoding of whole organism community DNA: towards bioinformatic harmonisation
Metabarcoding of DNA extracted from community samples of whole organisms (whole organism community DNA, wocDNA) is increasingly being applied to terrestrial, marine and freshwater metazoan communities to provide rapid, accurate and high resolution data for novel molecular ecology research. The growth of this field has been accompanied by considerable development that builds on microbial metabarcoding methods to develop appropriate and efficient sampling and laboratory protocols for whole organism metazoan communities. However, considerably less attention has focused on ensuring bioinformatic methods are adapted and applied comprehensively in wocDNA metabarcoding. In this study we examined over 600 papers and identified 111 studies that performed COI metabarcoding of wocDNA. We then systematically reviewed the bioinformatic methods employed by these papers to identify the state-of-the-art. Our results show that the increasing use of wocDNA COI metabarcoding for metazoan diversity is characterised by a clear absence of bioinformatic harmonisation, and the temporal trends show little change in this situation. The reviewed literature showed (i) high heterogeneity across pipelines, tasks and tools used, (ii) limited or no adaptation of bioinformatic procedures to the nature of the COI fragment, and (iii) a worrying underreporting of tasks, software and parameters. Based upon these findings we propose a set of recommendations that we think the wocDNA metabarcoding community should consider to ensure that bioinformatic methods are appropriate, comprehensive and comparable. We believe that adhering to these recommendations will improve the long-term integrative potential of wocDNA COI metabarcoding for biodiversity science.
Creedy, Thomas; Andújar, Carmelo; Noguerales, Víctor; Overcast, Isaac; Papadopoulou, Anna; Morlon, Hélène; Vogler, Alfried; Emerson, Brent C.; Arribas, Paula
Stereoselective Self-Assembly of DNA Binding Helicates Directed by the Viral β-Annulus Trimeric Peptide Motif
Combining coordination chemistry and peptide engineering offers extraordinary opportunities for developing novel molecular (supra)structures. Here, we demonstrate that the β-annulus motif is capable of directing the stereoselective assembly of designed peptides containing 2,2′-bipyridine ligands into parallel three-stranded chiral peptide helicates, and that these helicates selectively bind with high affinity to three-way DNA junctions.
Gómez-González, Jacobo; Bouzada, David; Pérez-Márquez, Lidia A.; Sciortino, Giuseppe; Maréchal, Jean-Didier; Vázquez López, Miguel; Vázquez, Eugenio
Comparative assessment of microsatellite and retrotransposon-based markers for genetic characterization of commercial banana cultivars (Musa spp.)
Banana cultivars of agronomic interest have been genetically characterized using two different molecular markers. On the one hand, a panel of 14 trinucleotide single sequence repeats (SSRs or microsatellites) was optimized for homogeneous PCR conditions. It was tested with 50 individuals from seven cultivars, yielding 76 alleles and 5.4 ± 1.8 alleles per locus, while the presence of cultivar-exclusive alleles allowed the discrimination of all cultivars. On the other hand, a retrotransposon-based marker system named inter-primer binding site (iPBS) was implemented for the first time in the Musa genus. A total of 120 bands were detected in eight different Musa cultivars, from which 65.8% were polymorphic and 23.3% were cultivar exclusive. Both techniques allowed a cut-off identification of all cultivars studied, but overall, iPBS analysis was a more straightforward and economical choice. Despite the fact that we were unable to distinguish local banana varieties belonging to the same cultivar, new cultivar-specific molecular markers have been developed for the Musa genus, which could be used to guide new breeding programmes and maintain high quality of Plátano de Canarias.
González Carracedo, Mario; Tejera-Pérez, Hugo; Hernández Ferrer, Mariano; Jiménez Arias, David; Pérez Pérez, José Antonio
Iron(II) and Copper(I) Control the Total Regioselectivity in the Hydrobromination of Alkenes
A new method that allows the complete control of the regioselectivity of the hydrobromination reaction of alkenes is described. Herein, we report a radical procedure with TMSBr and oxygen as common reagents, where the formation of the anti-Markovnikov product occurs in the presence of parts per million amounts of the Cu(I) species and the formation of the Markovnikov product occurs in the presence of 30 mol % iron(II) bromide. Density functional theory calculations combined with Fukui’s radical susceptibilities support the obtained results.
Cruz, Daniel A.; Sinka, Victoria; de Armas, Pedro; Steingruber, Hugo Sebastián; Fernández, Israel; Martín, Víctor S.; Miranda, Pedro O.; Padrón, Juan I.
Land Stewardship and Protection of an Endangered Plant Species in an Insular World Biosphere Reserve
Lotus eremiticus is an endemic species from La Palma World Biosphere Reserve. It has a small distribution range, low population size, and is threatened by introduced herbivores. Since these threats have not been removed from the protected area, they were excluded by building a fence. The land where the species grows is private property, so an agreement with the landowner was reached to permit measures to favor its recovery. During 2008-2019, as a result of this agreement and the conservation efforts, a large population increase occurred, from the initial 5 individuals to the 30 plants that are currently distributed at the original site. Furthermore, these measures allow the species to maintain stable population dynamics, meaning that this endangered species is itself capable of recovery if the threat is removed. This is a good example of how land stewardship is an effective tool to conserve endangered species.
Medina, Félix M.