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Introduction The Azores is an archipelago in the North Atlantic Ocean, comprising 9 inhabited volcanic islands. The main island, Sao Miguel, is situated 1,360 km west of continental Portugal. This archipelago presents a mild climate with average
Abstract
Between 8th July 2002 and 18th June 2004, aerosol samples were collected in Azores. Their inorganic composition was obtained by neutron activation analysis in order to study the differences of aerosols in two atmospheric altitudes of the central north Atlantic: (1) PICO-NARE observatory (Lower Free Troposphere-LFT) at Pico mountain summit (38,470ºN, 28,404ºW, 2,225 m a.s.l.) in Pico Island, Azores, where air masses from the surrounding continents (Africa, Europe, Central and North America) pass through, carrying aerosols with anthropogenic (Sb, Br, Mo, U, Se and Tb) and/or natural emissions (Fe, Co, La, Na, Sm, Cr, Zn, Hf, K and Th); (2) TERCEIRA-NARE station (Marine Boundary Layer) at Serreta (38,69ºN, 27,36ºW, 50 m a.s.l.), in Terceira Island, Azores, where natural aerosols (I, Cl, Na, Br and other soil related elements) are predominant. However, a combined interpretation of the data points out to a co-existence of the anthropogenic elements Sb and Mo, eventually with similar origins as the ones passing Pico Mountain summit. Very high concentrations and enrichment factors for Sb, Mo and Br in LFT, higher than the ones found in other areas, confirm atmospheric long-range transport mainly from the west boundary of north Atlantic; this may indicate eventual accumulation and persistence of those elements in the area due to the presence of Azores high pressures or the Hadley cells effect. A significant correlation between Fe and Yb and the enrichment of rare earth elements (La, Sm, Tb and Yb) and Th in LFT aerosols, both reflect a mineral dust intrusions from north Africa (Sahara and Sahel region).
Summary
The present study aims the identification and quantification of trace elements in samples of honey from the Azores and the Portuguese mainland. Elemental concentrations were determined for Al, Br, Cl, Cs, Cu, Eu, Fe, K, Mg, Mn, Na, Rb, Sb, and Zn. Some of these elements are essential dietary nutrients for humans. The essential elements, K and to a lesser extent Na and Cl were the most abundant in the honey samples. However, overall, the elemental content was very low, inferior to the recommended allowances for daily dietary intake (DDI), with the exception of Na whose concentration exceeded that of the recommended DDI. The results of the present investigation and data reported for other countries compare well. The honeys correlate much better when they are from Azores or from Portugal mainland, however, some good correlations were found between honeys from the islands and the mainland. The color of the honey, which depends of the flower-source, could have a role in the differences and similarities between the different honeys as suggested by the cluster analysis of the data. The correlation between honey, soil, tree bark and lichens, all collected in Azores, was poor.
Abstract
This article illustrates the use of chemometrics in the interpretation of aerosol data collected by a seven-wavelength aethalometer at the PICO-NARE observatory, in Pico island, Azores, Portugal. Samples were assessed through k 0-standardized, instrumental neutron activation analysis (k 0-INAA), and concentrations of up to 20 airborne elements were determined. The chemometric analysis by self-organizing maps (SOM) tried to identify groups of similarity for sampling events and chemical tracers, discriminating in this way each group of similarity thus obtained. Additionally, synoptic back trajectories for each of the sampling days distributed into four clusters were calculated, in order to associate the classified groups with possible pollution sources.
Summary
Within an extensive survey of lower and higher plants in the Azores' Terceira and Santa Maria islands, this study is focused on the evaluation of ectohydric bryophytes and bark from Cryptomeria japonica as an alternative to epiphytic lichens for air-monitoring purposes. Neutron activation analysis (k 0-NAA) has been applied to all field samples for elemental determinations. Judging from the present results, and since the islands embody most features of the whole archipelago, bryophytes do not appear as an option for further campaigns in the Azores, due to scanty supply and relatively poor performance as biomonitors. On the other hand, comparisons of bark with lichens collected at the same sites seem fairly good, and elements are enriched in bark to an even greater extent than in lichens. All things considered - including material availability and ecological concern - bark stands for a sensible choice for biomonitoring in the Azores.
One hundred lichen species and lichenicolous fungi are reported from the Azores, occurring on São Miguel and/or Terceira, collected in 2011 and 2014. Thirty-seven species are newly recorded to the Azores and seven are described as new to science: Byssoloma fuscum, Lecania azorica, Sphaerellothecium heterodermiae, S. parmotremae, Stigmidium micareae, S. subcladoniicola, Thelocarpon microsporum.
Abstract
This work addresses the chemical features of topsoils from Pico, São Jorge and São Miguel islands (Azores, Portugal), resulting from the weathering of more or less recent volcanic materials, namely pyroclastic debris, scoriae and basaltic rocks. The fractions under 64 μm of the surface-soil samples (0–10 cm) were put through k 0-standardized, instrumental neutron activation analysis (k 0-INAA), and their contents in 29 chemical elements were determined. Overall, the results show the chemical composition in the top horizon of soils to be correlated with the type of initial material, as well as with the age of formation of the island. The more relevant differences between the surveyed islands are: (1) a positive Ce anomaly in soils from São Miguel, most probably due to the higher age of that island; and (2) a fractionation between heavy and light rare-earth elements (REEs) in São Miguel, not found in the younger Pico and São Jorge. Other than the islands’ age, terrain altitude seems another relevant factor in differentiating the topsoils’ composition.
Abstract
Within an extensive survey of prevalent lower and higher plants in the Azores’ islands, with a view to their monitoring potential for airborne elements at ground level, and then to an eventual use in evaluation routines for the archipelago, epiphytic lichens were collected from Cryptomeria japonica (Japanese cedar) trunks all across Terceira and Santa Maria islands. After suitable procedures, thalli samples were put through instrumental neutron activation analysis (INAA; k 0-variant) for elemental concentrations. Providing an overall view of micro-and trace-element levels in representative foliose-and fruticose-type species, the data of high-level elements agree generally well for genera with distinct species, with a relatively low interspecies variability. Principal-component analysis of the whole set of results discriminates clearly between two morphological factors, corresponding to foliose and fruticose species, and likely among four major origins of elemental inputs: soil/dust (two factors), sea spray and an antimony-related source. All things considered, and accounting for its availability and ubiquity, Parmotrema bangii seems an adequate choice for further lichen-based, biomonitoring campaigns in the Azores archipelago.
How are bryophyte alpha and beta diversities distributed across spatial scales along an elevational gradient in an oceanic island? Which mechanisms and drivers operate to shape them? Starting from a multiscale hierarchical sampling approach along an 1000 m elevational transect, we used additive diversity partitioning and null modeling to evaluate the contributions of the alpha and beta diversity components to overall bryophyte diversity in Terceira Island, Azores. Substrate-level diversity patterns were explored by means of the Sørensen Similarity Index and the Lloyd Index of Patchiness. Elevation-level beta diversity was decomposed into its replacement and richness differences components, with several environmental variables being evaluated as diversity predictors. Bryophyte diversity proved to be primarily due to beta diversity between elevation sites, followed by diversity among substrates. Compositional differences between neighboring sites decreased with elevation, being mainly caused by species replacement and correlating with differences in relative humidity and disturbance. At the substrate level, we found a great homogeneity in terms of species composition, coupled with a low substrate specialization rate. We conclude that, in Terceira’s native vegetation patches, regional processes, such as environmental gradients associated with elevation, play a greater role in shaping bryophyte diversity than local processes. Moister and less disturbed areas at mid-high elevation harbor a richer bryoflora, consistently more similar and stable between neighbouring sites. Simultaneously, the different substrates available are somewhat ecologically redundant, supporting few specialized species, pointing to these areas providing optimal habitat conditions for bryophytes. Our findings provide a better understanding of how bryophyte diversity is generated in Terceira Island, indicating that management and conservation measures should focus on island-level approaches, aiming to protect and rehabilitate additional natural vegetation patches at different elevations, especially in the severely disturbed lowlands.
Abstract
The distribution of the chemical element during weathering of trachyandesite in S. Miguel Island (Azores, Portugal), and in mosses and lichens growing on these rocks, was studied using instrumental neutron activation analysis. A general enrichment of rare earth elements (REEs), a Ce positive anomaly (partial oxidation after primary apatite dissolution) and a Eu negative anomaly (Eu2+ in plagioclases/clay minerals) are observed with increasing weathering. Mosses and lichens are Ce and Eu depleted, indicating that the main REE uptake is done via absorption from REE3+ secondary phosphates, probably together with P (essential nutrient). Zn, Br and Sb show higher enrichment factors in lichens and mosses.
