Los flujos netos hidrológicos y químicos asociados de un Bosque de laurisilva en Tenerife

Se propone conocer el ciclo hidrológico interno de un bosque de laurisilva en la isla de Tenerife para lo cual se estudia la precipitación penetrante, el escurrido cortical de los árboles, la evaporación por interceptación de la cubierta y los aportes de elementos quimicos de la lluvia al sustrato. La metodología se basa en el estudio de una parcela de 3.390 m2, situada a 820 metros de altitud, en la vertiente norte de la isla de Tenerife y entre dos barranco

TEMPORAL TRENDS OF HEAVY METAL CONCENTRATIONS IN BROWN MACROALGAE FROM COASTAL ENVIRONMENTS

Heavy metals are one of the major drivers of ecological changes in coastal ecosystems. Macroalgae are primary producers of great relevance for ecosystem structure and functioning in these environments, and play a key role in the trophic transfer of these contaminants in the food web. Here, we present the most extensive assessment until now (>3500 records) of heavy metal concentrations in brown macroalgae (Class Phaeophyceae) sampled between 1933 and 2020 worldwide. The study compiles this information from 420 peer reviewed articles to be used as a proxy of global long-term changes in metal concentrations. We report the first detailed multi-decadal time series of Cd, Co, Cr, Cu, Fe, Hg, Mn, Pb and Zn in algae using generalized additive models (GAMs), confirming a significant decrease in metal contamination in the world’s coastal environments since ca. the 1970s for Pb (84% reduction), Zn (79%), Cd (77%) and Cu (72%), since the 1980s for Mn (75%) and Hg (65%), and since the 1990s for Cr (66%), Fe (64%) and Co (60%). Important environmental consequences for the whole aquatic ecosystem, even for human health, may be expected from these changes. The present results provide a building block for the overall evaluation of the status and trends of marine metal contamination, and will help researchers and policy makers to promote new legal regulations and environmental goals against pollution

Species turnover during secondary succession in a laurel forest stand 60 years after clearcutting

Aim of study: The present study was designed to evaluate the effects of clearcutting and recovery of a laurel forest stand, 50 years after felling.Area of study: Laurel forest stand in Agua García, Tenerife (Canary Islands)Material and methods: Structural stand parameters were measured in a large patch of laurel forest.Main results: The results revealed that Erica arborea and Ilex canariensis have acted as pioneer species in the broad sense of the term, while Morella faya has remained abundant throughout the study. Persea indica became increasingly dominant throughout succession, as indicated by several different structural parameters.Research highlights: Recovery of the laurel forest after clearcutting has been possible in some areas without any further forest management, as indicated by the species composition and forest structure.Key words: Canary Islands; Ecological Restoration; Laurel forest; Succession

What dead seaweeds can tell us about metal uptake and their application to control marine pollution

The mechanisms of trace element uptake by seaweeds are still unknown, despite being key to understand the impact of pollution in coastal environments. This knowledge gap, in addition to the lack of standardization, have also hindered the use of seaweeds to monitor seawater pollution. To address these shortcomings, we tested the use of devitalization as a pre-exposure treatment for brown seaweed transplants, and we compared devitalized and fresh transplants to gain some insights into the mechanisms of element uptake. We exposed four types of Fucus vesiculosus transplants in 6 sites for 4, 8 and 20 days: fresh and devitalized (dried or boiled) algal segments held in mesh bags, and whole algal thalli imitating natural conditions. We then determined he concentrations of 11 trace elements in the algal tissues. The element concentrations were highest in the devitalized transplants, but the material lost consistency and weight throughout the exposure period, limiting their use to short periods. We proposed several factors that may contribute to the different accumulation patterns between treatments, and examined the implications for the uptake mechanisms, revealing that two of the most important are surface adsorption of sediment particles and chemical bounds to extracellular componentsThis study is part of the project PID2022–142802NB-I00 awarded by the Spanish Ministerio de Ciencia e Innovación. The authors belong to the Grupo de Referencia Competitiva GRC GI-1252/GPC2020–23 (ED431C 2020/19) which is co-funded by ERDF (EU). A. Vázquez-Arias is grateful to the Spanish Ministerio de Ciencia, Innovación y Universidades for a grant awarded within the Programa de Formacion de Profesorado Universitario (grant number FPU19/01989)S

Levels of Antioxidant Compound Glutathione in Moss from Industrial Areas

Plants possess a wide range of cellular mechanisms that help them tolerate potentially toxic substances. Several studies that were carried out under laboratory conditions have demonstrated that the antioxidant compound glutathione plays a role in enabling mosses to tolerate high levels of heavy metals without toxic effects. However, until now, the antioxidant levels have not been studied in mosses under field conditions. In this study, we aimed to clarify the antioxidant concentrations of glutathione in the terrestrial moss Pseudoscleropodium purum growing in industrial environments characterised by high atmospheric levels of Cd, Ni, and Pb, and to evaluate the potential use of the compound as a biomarker. The results indicated the existence of a glutathione threshold response, which was significantly correlated with the metal toxicity and which may be influenced by metal bioavailability. Although future studies are needed to strengthen the findings, the present study suggests that total concentration of glutathione in P. purum could therefore be used as a biomarker in air pollution biomonitoring studies, provided that metal bioavailability is taken into account

Plant-air partition coefficients for thirteen urban conifer tree species: Estimating the best gas and particulate matter associated PAH removers

Polycyclic Aromatic Hydrocarbons (PAHs) are an important class of pollutants which mostly come out from incomplete combustion of organic materials including fossil fuels. For this reason, they are often found at high concentrations in cities, contaminating air with their gas and particle phase. While European Union policies try to reduce their concentrations, huge efforts are still devoted to mitigate the pollution by PAHs. One such measure of mitigation is the use of plants in capturing PAHs and other chemicals due to the ability of leaves in filtering both gas and particle fractions. In this work thirteen conifer species among those frequently living in temperate and Mediterranean cities were selected and concentrations of 16 PAHs were measured in needles. The data for spruce were used to back-calculate air concentrations of PAHs which were later used to obtain specific equations of plant-air partition coefficient (K-PA). The results showed that the difference in total PAH uptake between the most (Pinus pinaster) and the least (Picea abies) efficient tree was close to an order of magnitude. Looking to the capability of the different species in enriching the particulate matter (PM) associated fraction of PAHs on their needles, Pinus pinaster was instead the least important (3.4% of total PAHs), while Cupressus lusitanica was the most important (34% of total PAHs). The new K-PA equations can be used to fine tune the PAH uptake of a specific amount of plant biomass on air concentration reduction

Accumulation of polycyclic aromatic hydrocarbons in the devitalized aquatic moss Fontinalis antipyretica: From laboratory to field conditions.

AbstractThis work aims to test the feasibility of a Fontinalis antipyretica devitalized moss clone to uptake and accumulate polycyclic aromatic hydrocarbons (PAHs) from surface waters. To assess the capability of the devitalized clone to accumulate PAHs, in the laboratory, moss was placed in water and spiked with increasing concentrations of 16 PAHs, and under field conditions, the moss was transplanted to 22 sites of Galicia (Spain) rivers. In general, PAH concentrations in water samples were lower than the maximum allowable concentrations from Directive 2013/39/EU, so the sampling sites did not show water PAH contamination. The exponential accumulation kinetic in the laboratory trial highlights a good capability of the devitalized moss clone to accumulate total PAHs. In field experiments, the hydrogeological conditions and the low emission sources caused low concentrations of PAHs in the water system and, consequently, in the transplants, although an enrichment can be observed for several PAHs. Overall, the devitalized clone of F. antipyretica can uptake and accumulate PAHs in water and may be useful in bioremediation strategies

Genetic structuring of the moss Pseudoscleropodium purum sampled at different distances from a pollution source

In this study, we used amplified fragment length polymorphism analysis to investigate the genetic structure of the terrestrial moss Pseudoscleropodium purum (Hedw.) M. Fleish. naturally exposed to different levels of atmospheric deposition of heavy metals. We also determined the heavy metal concentrations in samples of this moss to evaluate whether there was a relationship between atmospheric pollution and population genetic diversity. A low level of genetic diversity and a limited gene flow among populations were observed which is in accordance to the prevalence of asexual reproduction in this species. In addition, no significant correlation was found between metal content and gene diversity in P. purum, probably because of the common history of the sampled populations and/or to the lack of a drastic reduction of the size of the population; nonetheless, a clear genetic structure was evident in relation to the existing pollution gradient. Thus, based on the results of the principal coordinate analysis and Bayesian analysis of the genotypes, the mixed structure of the second most polluted population would suggest an ongoing differentiation of metal-tolerant genotypes in the most polluted sites of the sampling area

Analysis of intra-thallus and temporal variability of trace elements and nitrogen in Fucus vesiculosus: Sampling protocol optimization for biomonitoring

To advance the methodological standardization of the biomonitoring technique using macroalgae, we comprehensively characterized the intra-thallus and temporal patterns of variation in concentrations of a wide set of elements (Al, As, Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, N) and δ15N signal in 6 consecutive Fucus vesiculosus apical dichotomous sections collected monthly over a four-year period (2015–2019) at 3 sites on the NW coast of Spain. The concentrations of Al, Co, Fe, Ni, Pb and Zn increased significantly from the youngest to the oldest dichotomies regardless of the sampling time and collection site; As, Cd, N and δ15N showed the opposite trend. Time series analysis revealed a significant and consistent seasonal variation of As, Cd, Co, Cu, Fe, Hg, Ni, Zn, N and δ15N concentrations, with maximum values in winter and minimum values in summer. We discussed the possible mechanisms driving these two sources of variation, and proposed an efficient and effective sampling strategy to minimize their impact in the results of biomonitoring studies, in which the part of the algal thallus selected for chemical analysis and the sampling frequency were carefully considered. This protocol will improve the conclusions and comparability of biomonitoring data from coastal environments.En prens