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1.
Chemosphere ; 262: 128373, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33182143

RESUMEN

Since aquatic ecosystems receive runoff of most anthropogenic pollutants, risk assessment tools and protocols have been developed in order to protect them. However, most ecological risk assessments focus on the study of single species exposed to a single chemical, overlooking the environmental reality of multiple chemical exposures and stresses over generations. To advance in realistic predictions of population and community changes, the environmental disturbance history should be considered. The aim of this study was to evaluate how environmental disturbance history (continuous expected sublethal exposure to one chemical for several generations) determines populations' responses to another stressors. The experiments were performed with Daphnia magna as model organisms. To create a disturbance history, dimethoate was used as first stressor at two different concentrations: medium (0.089 mg·L-1) and high (0.89 mg·L-1). The population exposed to medium concentration ("vulnerable population") showed no differences from the control population in the selected parameters (body size and reproductive success). Our interest in the vulnerable population was to determine whether, after a first stressor, the detected non-effect hides a population impairment, which might undermine populations' responses to future stressors. After 4 generations under dimethoate exposure, the vulnerable D. magna population was exposed to a second chemical stressor (glyphosate) and an environmental stressor (food scarcity) as compared to control. The vulnerable population showed both less resistance to glyphosate and less resistance to starvation, corroborating the hypothesis that a disturbance history of continuous expected sublethal chemical exposures undermines populations' responses to further chemical and environmental stressors.


Asunto(s)
Contaminación Ambiental/estadística & datos numéricos , Animales , Daphnia/efectos de los fármacos , Ecosistema , Reproducción/efectos de los fármacos
2.
Sci Total Environ ; 753: 142158, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207432

RESUMEN

Increasing threats to freshwater biodiversity from environmental changes and human activities highlight the need to understand the linkages between biological communities and their environment. Species richness has dominated our view of biodiversity patterns for over a century, but it is increasingly recognized that a trait-based, causal view of biodiversity may be more meaningful than species richness or taxonomic composition. This rationale has led to the exploration of functional diversity (FD) indices to quantify variation in traits that mediate species' contributions to ecosystem processes. In the present study, we quantified FD of fish communities in two large shallow lakes in China with different disturbances level using long-term monitoring data sets. Random-Forests regression was applied to examine how changes in FD were related to natural and human-related environmental variables. Fish stocking, water quality, climate, and hydrological changes were identified as the most important predictors of FD long-term trends. However, the major drivers of FD differed between two lakes, i.e., human activities explaining a greater proportion of FD variance in Lake Taihu, whereas physicochemical environmental factors prominently explained FD variance in Lake Hulun. Moreover, FD indices appeared more sensitive than species richness to multiple disturbances, suggesting that functional traits can be used to detect ecosystem alterations. This study offers insight into how FD can improve our understanding of the associations between fish communities and environmental changes of relevance also for lake and fisheries management.


Asunto(s)
Ecosistema , Lagos , Animales , Biodiversidad , China , Peces , Humanos
3.
Sci Total Environ ; 753: 141884, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207442

RESUMEN

Understanding how plants and earthworms regulate soil-based ecosystem services can guide design and management of built environments to improve environmental quality. We tested whether plant and earthworm activity results in trade-offs between soil carbon (C) retention and water quality. In a 2 × 2 factorial random block design, we introduced shrubs (Aronia melanocarpa) and earthworms (Lumbricus terrestris) to turfgrass (Lolium perenne) sandy loam mesocosms in a greenhouse. We measured soil respiration and soil microclimate every two weeks and leachate every two months. After 15 months, we assessed C and nitrogen (N) in bulk soil and aggregates (> 2000, 2000-250, 250-53 µm). Turfgrass mesocosms with earthworms retained less soil C (6.10 ± 0.20 kg/m2), especially when warmer. Soils planted with shrubs were drier and had 7% lower mean respiration rates than soils without shrubs. Turfgrass mesocosms with both shrubs and earthworms retained more soil C (6.66 ± 0.25 kg/m2), even when warmer, and held ~1.5 times more C in >2 mm aggregates than turfgrass-only mesocosms. Turfgrass mesocosms with shrubs and earthworms leached nitrate-N with increased respiration and retained phosphate-P and dissolved organic carbon (DOC) when wetter. In contrast, turfgrass mesocosms with only shrubs had the opposite response by leaching less nitrate-N with increased respiration, and more phosphate-P and DOC when wetter. Overall, shrub and earthworm activity in turfgrass mesocosms led to soil C-nutrient retention trade-offs. Our results reveal potential challenges in managing built environments to both retain soil C and improve water quality.


Asunto(s)
Oligoquetos , Animales , Carbono/análisis , Ecosistema , Suelo , Calidad del Agua
4.
Sci Total Environ ; 753: 141915, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207447

RESUMEN

In this study we focused on urban bird diversity across Mexico, a megadiverse country, with a special focus on the relative role of urban greenspaces and heavily-built sites. We considered a country-wide approach, including 24 different sized Mexican cities. Our aims were to describe the urban bird diversity in focal cities and further assess the relationships between it and the biogeographic region where cities are located, their size, elevation, and annual rainfall. Additionally, we evaluated differences in the functional composition of bird communities in both studied urban scenarios (i.e., urban greenspaces, heavily-built sites). Our results confirm that urban greenspaces are home to a large proportion of species when contrasted with heavily-built sites. While total species richness and species richness of greenspaces were related with the cities' biogeographic region -with higher species richness in the Neotropical region and Transition Zone-, the relationship did not hold true in heavily-built sites. We found that annual rainfall was negatively related to bird richness in heavily-built sites, suggesting that species from arid systems can be more tolerant to urbanization. Regarding the bird functional group assessment, results show a clear differentiation between the functional groups of greenspaces and those of heavily-built sites, with granivores and omnivores associated with the latter and a highly diverse array of functional groups associated with urban greenspaces.


Asunto(s)
Biodiversidad , Aves , Animales , Ciudades , Ecosistema , México , Urbanización
5.
Sci Total Environ ; 753: 142194, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207455

RESUMEN

Phyllospheric microbes play a crucial role in the biological decomposition of plant litter in wetland ecosystems. Previous studies have mainly focused on single stages of decomposition process, and to date there have been no reports on dynamic changes in the composition of phyllospheric microbes during the multiple stages of decomposition from living plant to death. Here we investigated fungal and bacterial community succession in the leaf litter of Schoenoplectus tabernaemontani, a wetland plant species using sequencing of the both fungal ITS and bacterial 16S genes. Our results revealed that, over the whole period of decomposition, the fungal communities underwent more distinct succession than did the bacterial communities. Proteobacteria dominated throughout the entire period, while, across different decomposition stages, the Ascomycete fungi were gradually replaced by the Ciliophora and Rozellomycota as the dominant fungi. Network analysis revealed higher degrees of species segregation and shorter average path lengths between species of fungi compared with species of bacteria. This suggests that fungal communities may harbor more niches and functional diversity and are potentially more susceptible to external interference than are bacterial communities. During decomposition, the contents of leaf cellulose, hemicellulose and lignin in the litter were significantly (p < 0.01) correlated with the fungal communities, and abiotic factors accounted for 89.8% of the total variation in the fungal communities. In contract, abiotic factors only explained 6.10% of the total variation in bacterial communities, suggesting external environments as drivers of fungal community succession. Overall, we provide evidence that the complex litter decay in wetlands is the result of a dynamic cross-kingdom succession, and this process is accompanied by distinct phyllospheric fungal community dynamics.


Asunto(s)
Microbiota , Micobioma , Bacterias/genética , Ecosistema , Hongos , Hojas de la Planta , Microbiología del Suelo , Humedales
6.
Sci Total Environ ; 753: 141902, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207459

RESUMEN

One of negative side-effects of usage of bio-renewables might be generation of mineral (ash) material, potential source of environmental pollution. A hypothesis was that bottom ash (BA; from biomass cogeneration facility) could be efficiently (re) used in soil chemical conditioning similarly to widely-used dolomite-based soil conditioner (DO; from Croatian Dinaric-coastal region) which we tested by: i) physicochemical characterisation of BA and DO, and ii) bioassay with Raphanus sativus cultivated in acidic soil amended with BA or DO. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) confirmed complex chemical/physical structures and morphology between amendments, X-ray diffraction (XRD) showed their distinctive mineralogy with predominantly dolomite (in DO) vs. quartz and calcite (in BA), while secondary ion mass spectrometry (SIMS) revealed their diverse elemental/isotopic composition. The BA or DO amendments ameliorated soil acidity, increased available P, K and most other nutrients, but not Cd. The BA or DO amendments improved vegetative growth and edible hypocotyl yield. However, both amendments also increased Cd accumulation in all radish tissues, which was unexpected given the alkaline matrix of bio-ash and dolomite that would be likely to facilitate retention and immobilisation of toxic Cd. Thus, thorough characterisation and evaluation of BA- and/or DO-based materials and relevant soils (with an emphasis on metal sorption/immobilisation) prior to application in (agro) ecosystems is crucial for producing food clean of toxic metals.


Asunto(s)
Raphanus , Contaminantes del Suelo , Biomasa , Cadmio/análisis , Carbonato de Calcio , Ceniza del Carbón , Ecosistema , Magnesio , Nutrientes , Suelo , Contaminantes del Suelo/análisis
7.
Sci Total Environ ; 753: 141819, 2021 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-33207461

RESUMEN

The occurrence and health risks of toxic organic contaminants (TOCs) in the funeral industry are relatively under-studied compared to other industries. An increasing body of literature reports TOCs including emerging contaminants in the funeral industry, but comprehensive reviews of the evidence are still lacking. Hence, evidence was analysed to address the proposition that, the funeral industry constitutes several hotspot reservoirs of a wide spectrum of TOCs posing ecological and human health risks. TOCs detected include embalming products, persistent organic pollutants, synthetic pesticides, pharmaceuticals, personal care products and illicit drugs. Human cadavers, solid wastes, wastewaters and air-borne particulates from autopsy, thanatopraxy care facilities (mortuaries, funeral homes), cemeteries and crematoria are hotspots of TOCs. Ingestion of contaminated water, and aquatic and marine foods constitutes non-occupational human exposure, while occupational exposure occurs via inhalation and dermal intake. Risk factors promoting exposure to TOCs include unhygienic burial practices, poor solid waste and wastewater disposal, and weak and poorly enforced regulations. The generic health risks of TOCs are quite diverse, and include; (1) genotoxicity, endocrine disruption, teratogenicity and neurodevelopmental disorders, (2) development of antimicrobial resistance, (3) info-disruption via biomimicry, and (4) disruption of ecosystem functions and trophic interactions. Barring formaldehyde and inferential evidence, the epidemiological studies linking TOCs in the funeral industry to specific health outcomes are scarce. The reasons for the lack of evidence, and limitations of current health risk assessment protocols are discussed. A comprehensive framework for hazard identification, risk assessment and mitigation (HIRAM) in the funeral industry is proposed. The HIRAM includes regulatory, surveillance and control systems such as prevention and removal of TOCs. Future directions on the ecotoxicology of mixtures, behaviour, and health risks of TOCs are highlighted. The opportunities presented by emerging tools, including isotopic labelling, genomics, big data analytics (e.g., machine learning), and in silico techniques in toxicokinetic modelling are highlighted.


Asunto(s)
Plaguicidas , Contaminantes Químicos del Agua , Autopsia , Cementerios , Ecosistema , Monitoreo del Ambiente , Humanos , Plaguicidas/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
8.
Sci Total Environ ; 751: 142335, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-33181979

RESUMEN

Forest soils are being exposed to nutrient deficiency and acidification at increasing rates as a result of intensive management. Mineral fertilization, however, provides a way to improve soil nutrient balance. The aim of this study is to present the effects of mineral fertilization on the properties of forest soil 11 years after fertilization. Our research investigated the effects of dolomite, magnesite and serpentinite fertilization on the physicochemical properties of the soil, soil biological activity, and fungal diversity. We also determined the condition of a new generation of fir trees after mineral fertilization. In autumn, 2008, fertilizers (dolomite, magnesite and serpentinite, specifically) in the amount of 4000 kg.ha-1 were added to plots in the Wisla Forest District in Poland; one area was left unfertilized to act as the control area for this research. Our results reveal that all fertilization improved the selected soil's physicochemical properties (pH, Ca and Mg content) and accordingly, its biochemical activity; in particular, we found that dolomite (4000 kg.ha-1) contributed heavily to soil improvement. The findings also showed that soil pH and calcium content were strongly dependent on enzymatic activity, while dolomite fertilization resulted in a significant increase in biomass size in the fir trees included in this study. In addition to being associated with the highest plant biomass and amounts of enzymatic activity, dolomite-fertilized soil also had the highest number of fungal operational taxonomic units (OTUs): 403, compared to 322 OTUs in the control soil. Finally, the fungal communities in the control soil varied significantly from the fungal communities in soils fertilized with dolomite and serpentinite. The results of this research support mineral fertilization, and in particular, fertilization using dolomite in amounts of 4000 kg.ha-1, to improve soil nutrient supply and to shape the biological activity expressed by the enzymatic activity of forest soils.


Asunto(s)
Ecosistema , Suelo , Bosques , Polonia , Microbiología del Suelo , Árboles
9.
Sci Total Environ ; 751: 142263, 2021 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-33181984

RESUMEN

Structure and assembly processes of soil bacterial communities under different land use at karst areas remained poorly understood to date. To address this issue, soil samples from arable land and pristine forest over a karst cave, located in the acid rain impacted area, Hubei province, were collected and subjected to high-throughput sequencing and multivariate statistical analysis. Bacterial communities and functions remarkably distinguished between soils under different land use. Both edaphic properties (the content of SO42-, C/N, pH, TN) and weathering processes, such as Si concentration, Mg/Al and Ca/Al, significantly impacted on soil bacterial community structures. Variable selections were predominant ecological processes, and pH and SO42- concentration were of significance in community assembly. Random molecular ecological network analysis revealed a more stable and complex microbial network in the forest ecosystem, which can quickly response to environmental change. Forest soil bacteria were mainly phototrophs, involving in C and N cycles, whereas those in arable soils were mainly chemoheterotrophs, capable of degrading organic fertilizers due to anthropogenic activities as confirmed by the analysis of keystone taxa, indicators and functional prediction. These results reveal that land use constructed soil bacterial communities in different aspects such as the structure, potential functions, microbial interactions and correlations with environmental variables. To our knowledge, this is the first report on bacterial community assembly in karst soils under different land use which enhances our understanding about how land use impact on microbial interaction and community assembly processes.


Asunto(s)
Ecosistema , Suelo , Bacterias , Bosques , Microbiología del Suelo
10.
Sci Total Environ ; 750: 142234, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182167

RESUMEN

The increase in severity and occurrence of drought from environmental change poses a significant threat to freshwater ecosystems. However, many of the mechanisms by which periodic drought affects aquatic animals are poorly understood. Here we integrated physical, physiological, and behavioural measurements made in the field over a twelve-year period to provide a comprehensive understanding of the factors affecting the loss of body condition of fish in arid rivers, using the Critically Endangered freshwater sawfish (Pristis pristis) in the dryland Fitzroy River, Western Australia, as a model species. Sawfish lost condition throughout the long dry season in all years and had significantly poorer body condition throughout years characterized by low volumes of wet season flooding and little occurrence of overbank flooding. A mechanistic examination of factors leading to this loss of condition using measurements of body temperature, field energetics, and habitat use from telemetry techniques showed that the loss of condition throughout the season was likely due to substantial habitat compression and low productivity in drier years, while high rates of competition were more likely to drive this pattern in wetter years. This information can be used to forecast how climate change and water abstraction will affect aquatic fauna experiencing intermittent drought and can inform management decisions to help mitigate these threats.


Asunto(s)
Elasmobranquios , Inundaciones , Animales , Sequías , Ecosistema , Ríos , Estaciones del Año , Australia Occidental
11.
Sci Total Environ ; 750: 141707, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182172

RESUMEN

Ultraviolet (UV) filters are compounds utilized in many manufacturing processes and personal care products such as sunscreen to protect against UV-radiation. These highly lipophilic compounds are emerging contaminants of concern in aquatic environments due to their previously observed potential to bioaccumulate and exert toxic effects in marine ecosystems. Currently, research into the toxic effects of UV filter contamination of freshwater ecosystems is lacking, thus the present study sought to model the effects of acute and chronic developmental exposures to UV filters avobenzone, oxybenzone and octocrylene as well as a mixture of these substances in the freshwater invertebrate, Daphnia magna, at environmentally realistic concentrations. Median 48-hour effect and lethal concentrations were determined to be in the low mg/L range, with the exception of octocrylene causing 50% immobilization near environmental concentrations. 48-hour acute developmental exposures proved to behaviourally impair daphnid phototactic response; however, recovery was observed following a 19-day post-exposure period. Although no physiological disruptions were detected in acutely exposed daphnids, delayed mortality was observed up to seven days post-exposure at 200 µg/L of avobenzone and octocrylene. 21-day chronic exposure to 7.5 µg/L octocrylene yielded complete mortality within 7 days, while sublethal chronic exposure to avobenzone increased Daphnia reproductive output and decreased metabolic rate. 2 µg/L oxybenzone induced a 25% increase in metabolic rate of adult daphnids, and otherwise caused no toxic effects at this dose. These data indicate that UV filters can exert toxic effects in freshwater invertebrates, therefore further study is required. It is clear that the most well-studied UV filter, oxybenzone, may not be the most toxic to Daphnia, as both avobenzone and octocrylene induced behavioural and physiological disruption at environmentally realistic concentrations.


Asunto(s)
Daphnia , Contaminantes Químicos del Agua , Animales , Ecosistema , Protectores Solares/toxicidad , Rayos Ultravioleta/efectos adversos , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
12.
Sci Total Environ ; 750: 141252, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182174

RESUMEN

Anthropogenic activities are seriously endangering the conservation of biodiversity worldwide, calling for urgent actions to mitigate their impact on ecosystems. We applied machine learning techniques to predict the response of freshwater ecosystems to multiple anthropogenic pressures, with the goal of informing the definition of water policy targets and management measures to recover and protect aquatic biodiversity. Random Forest and Gradient Boosted Regression Trees algorithms were used for the modelling of the biological indices of macroinvertebrates and diatoms in the Tagus river basin (Spain). Among the anthropogenic stressors considered as explanatory variables, the categories of land cover in the upstream catchment area and the nutrient concentrations showed the highest impact on biological communities. The model was then used to predict the biological response to different nutrient concentrations in river water, with the goal of exploring the effect of different regulatory thresholds on the ecosystem status. Specifically, we considered the maximum nutrient concentrations set by the Spanish legislation, as well as by the legislation of other European Union Member States. According to our model, the current nutrient thresholds in Spain ensure values of biological indices consistent with the good ecological status in only about 60% of the total number of water bodies. By applying more restrictive nutrient concentrations, the number of water bodies with biological indices in good status could increase by almost 40%. Moreover, coupling more restrictive nutrient thresholds with measures that improve the riparian habitat yields up to 85% of water bodies with biological indices in good status, thus proving to be a key approach to restore the status of the ecosystem.


Asunto(s)
Ecosistema , Ríos , Monitoreo del Ambiente , Aprendizaje Automático , España , Agua
13.
Sci Total Environ ; 750: 142081, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182185

RESUMEN

The high biotic diversity supported by floodplains is ruled by the interplay of geomorphic and hydrological processes at various time scales, from daily fluctuations to decennial successions. Because understanding such processes is a key question in river restoration, we attempted to model changes in taxonomic richness in an assemblage of 58 macroinvertebrate taxa (21 gastropoda and 37 ephemeroptera, plecoptera and trichoptera, EPT) along two successional sequences typical for former braided channels. Individual models relating the occurrence of taxa to overflow and backflow durations were developed from field measurements in 19 floodplain channels of the Rhône floodplain (France) monitored over 10 years. The models were combined to simulate diversity changes along a progressive alluviation and disconnection sequence after the reconnection with the main river of a previously isolated channel. Two scenarios were considered: (i) an upstream + downstream reconnection creating a lotic channel, (ii) a downstream reconnection creating a semi-lotic channel. Reconnection led to a direct increase in invertebrate richness (on average x2.5). However, taxonomical richness showed a constant decrease as isolation progressed and reached an average of 2 for EPT and 7 for gastropods at the end of the scenarios. With more than 80% of the taxonomic models with an AUC equal or higher than 0.7 and slopes of linear relations between observed and predicted richness of 0.75 (gastropods) and 1 (EPT), the Boosted Regression Trees (BRT) provided a good basis for prediction of species assemblages. These models can be used to quantify a priori the sustainability and ecological efficiency of restoration actions and help floodplain restoration planning and management.


Asunto(s)
Ecosistema , Invertebrados , Animales , Francia , Hidrología , Ríos
14.
Sci Total Environ ; 750: 141969, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182191

RESUMEN

Worldwide, multiple stressors affect stream ecosystems and frequently lead to complex and non-linear biological responses. These combined stressor effects on ecologically diverse and functionally important macroinvertebrate communities are often difficult to assess, in particular species-specific responses across many species and effects of different stressors and stressor levels in concert. A central limitation in many studies is the taxonomic resolution applied for specimen identification. DNA metabarcoding can resolve taxonomy and provide greater insights into multiple stressor effects. This was detailed by results of a recent multiple stressor mesocosm experiment, where only for the dipteran family Chironomidae 183 Operational Taxonomic Units (OTUs) could be distinguished. Numerous OTUs showed very different response patterns to multiple stressors. In this study, we applied DNA metabarcoding to assess multiple stressor effects on all non-chironomid invertebrates from the same experiment. In the experiment, we applied three stressors (increased salinity, deposited fine sediment, reduced flow velocity) in a full-factorial design. We compared stressor responses inferred through DNA metabarcoding of the mitochondrial COI gene to responses based on morphotaxonomic taxa lists. We identified 435 OTUs, of which 122 OTUs were assigned to EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa. The most common 35 OTUs alone showed 15 different response patterns to the experimental manipulation, ranging from insensitivity to any applied stressor to sensitivity to single and multiple stressors. These response patterns even comprised differences within one family. The species-specific taxonomic resolution and the inferred response patterns to stressors highlights the potential of DNA metabarcoding in the context of multiple stressor research, even for well-known taxa such as EPT species.


Asunto(s)
Ríos , Salinidad , Animales , Código de Barras del ADN Taxonómico , Ecosistema , Monitoreo del Ambiente , Invertebrados/genética
15.
Sci Total Environ ; 750: 141296, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182202

RESUMEN

Marine mammals and the ecological functions they provide to coastal and pelagic ecosystems are increasingly threatened by the intensification of anthropogenic impacts. The Uruguayan coastline throughout the 20th century, like other coastal environments worldwide, has been the sink of a variety of trace metals derived from the rapid urbanization and industrialization of related land areas. This coastline is inhabited by two species of pinnipeds trophically and spatially segregated. Otaria byronia feeds in coastal environments while Arctocephalus australis preys mainly offshore. The present study aimed to analyze historic changes in concentrations of trace elements in teeth of both species from 1941 to the present day. We analyzed the dentin of 94 canine teeth using stable isotope analysis (δ13C) and ICP-MS to determine their feeding areas and the concentration of 10 trace elements (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) respectively. The concentration of Cr was significantly higher during '70-'80s, in both species coinciding with tannery industry development. Both species of pinnipeds have been differentially exposed to trace elements depending on their feeding area. A pelagic diet, possibly based on squid, increased the concentration of Cd in A. australis, while O. byronia has been more exposed to anthropogenic Pb and Cu associated to a costal and more benthic diet. Our results highlight dentin as a reliable matrix for historic studies on the exposure to trace elements. In light of our results, the O. byronia's declining population could be the result of the synergistic effects of trace elements together with other ecological pressures faced in their environment.


Asunto(s)
Caniformia , Metales Pesados , Oligoelementos , Contaminantes Químicos del Agua , Animales , Ecosistema , Monitoreo del Ambiente , Hábitos , Metales Pesados/análisis , Oligoelementos/análisis , Contaminantes Químicos del Agua/análisis
16.
Sci Total Environ ; 750: 142306, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182203

RESUMEN

The decomposition of plant litter is a key link in global C budgets and provides strong feedback to changes in climate and biogeochemical cycles. However, the combined effects of global warming and plant litter quality on the rate of plant litter decomposition and nutrient dynamics in alpine ecosystems are still poorly understood. We conducted a warming experiment to investigate the effects of litter quality and temperature on decomposition rates and variations in nutrients of four common herbaceous plants (low-quality litter species Stipa purpurea and Carex moorcroftii and high-quality litter species Astragalus confertus and Leontopodium nanum) during 2011-2016. During the initial stages of decomposition, warming had no significant effect on the mass loss of plant litter for low-quality litter species, but in the later stages of decomposition, it had a negative effect on the mass loss across all species (P < 0.05). Litter quality was the best predictor of N and P release/immobilisation during the decomposition of aboveground plant litter. Low-quality litter had the highest immobilisation of N at about 80% of the initial remaining mass; nutrients were then released in the following stages of decomposition. However, the fraction of initial P decreased with the mass remaining during the initial and later phases of decomposition, but a short period of P immobilisation occurred in the middle phase of decomposition. For high-quality litter, the fraction of initial N and P decreased with the mass remaining during the whole decomposition process. Warming had a marginal influence on the N and P dynamics throughout the decomposition process. Our study showed that the decay of plant litter was strongly suppressed by warming climate and that the N and P dynamics on the investigated Tibetan grassland were mainly regulated by litter quality, providing valuable insights into the biogeochemical cycles of nutrients in alpine ecosystems.


Asunto(s)
Ecosistema , Pradera , Hojas de la Planta , Plantas , Poaceae , Tibet
17.
Sci Total Environ ; 750: 141669, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182204

RESUMEN

Abandoned mine sites are a cause of great environmental concern, being potential sources of toxic elements for adjacent aquatic ecosystems with intrinsic difficulties for their management (i.e. episodic nature of pollution, technical difficulties and high costs of monitoring, remoteness). Aquatic macrophytes can find effective application in these situations, providing cost-effective data for instream water quality assessment. In this study, native and transplanted specimens of the aquatic moss Platyhypnidium riparioides were used to evaluate metal(loid) contamination in a river receiving multiple acidic and metalliferous drainages from sulphide mineralized areas and derelict mines. Analysis of native P. riparioides thalli was used to identify, in the upland course of the river, the pattern of contamination (As, Cd, Cu, Pb and Zn) which was related to the geo-environmental features of the watershed and the nearby historical mining areas. Attenuation of metal(loid) availability in the lowland river, apparently due to eco-hydrological and physic-chemical processes, was also highlighted by spatial trends of concentrations data of native and transplanted moss. The latter, deployed for 21 days at specific stretches of the river and in a tributary hydrologically connected with a dismissed mine, supported the identification of point sources (i.e. mine effluents, metallurgical waste piles amassed on the banks of the river) and the reckoning of their quantitative impact on different segments of the watercourse. By exploring multi-elemental and native-to-transplant relationships, differences in metal(loid) accumulative capacities were recognized between sampled thalli and exposed moss bags in relation to the severity of the contamination. The observed discrepancy in the accumulation of As, Fe, Ni and Pb in highly contaminated areas between native and transplanted moss of P. riparioides raises questions on the possible competing mechanisms of element uptake and retention. These findings prompt studies to discern possible limitations of the transplanting moss technique under extreme stream-quality conditions.


Asunto(s)
Metales Pesados , Contaminantes Químicos del Agua , Ecosistema , Monitoreo del Ambiente , Metales/análisis , Metales Pesados/análisis , Ríos , Contaminantes Químicos del Agua/análisis
18.
Sci Total Environ ; 750: 142327, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182209

RESUMEN

Currently, the global carbon footprint of cement industry is nearly 7 to 8% and this number is expected to grow in the near future given the continued global demand of cement usage in the construction and other sectors. Additionally, extraction of sand from the coastal and riverine environment is detrimental to ecosystem health and also gives rise to sand mafia in many developing countries. Biochar has the potential to sequester CO2 in cement mortars. The purpose of this study was to valorise a waste biomass (poultry litter) to carbon-rich biochar and utilise as filler material to replace the sand in the range of 10-40% of the total weight in cement. A total of four mix designs each with three replicates at 10%, 20%, and 40% replacement of sand and control (0% biochar addition) were investigated for their mechanical, durability and micro-computed tomography (CT) analysis. The results showed that the flexural strength of the composites at 20% biochar replacement of sand was improved by 26% when compared to control. Biochar addition lowered the thermal conductivity of the cement mortars and was optimised at 10% addition. The density of the mortars decreased ~20% with 40% biochar addition. Micro-CT analysis showed nearly a five-fold increase in the 2-dimensional porosity of the samples, from 2.5% (control) to 12% for samples which had 40% biochar; however, no marked changes were noticed for samples at 20% biochar addition. Taking mortar plastering as an example for 100 m2 area with standard 12 mm thickness revealed that CO2 emissions decreased 20% when sand was replaced with 40% biochar as compared to control specimen. It was concluded that biochar has the potential to replace the sand in the mortars for improving toughness, lowering thermal conductivity and density of the cement composites.


Asunto(s)
Ecosistema , Carbón Orgánico , Fuerza Compresiva , Porosidad , Microtomografía por Rayos X
19.
Sci Total Environ ; 750: 142370, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182210

RESUMEN

Plastic debris is ubiquitous in aquatic systems and has been proven vehicles for the transport of various pollutants including trace organic compounds. Nanoplastics have large specific surface area and hydrophobic characteristics and therefore are capable of adsorbing other organic or inorganic chemicals from the environment. Antibiotics, as another class of emerging contaminants, have raised significant research concern in recent years as they pose threats to the ecosytems and human health. Nevertheless, little information is available on the adsorption behaviors of antibiotics onto nano-sized plastics. The toxicity of combined nanoplastics and antibiotics is also largely unknown. In this study, the physicochemical and thermodynamic interactions between representative nanoplastics, which containing a carboxyl functional group of polystyrene nanoplastics (PS-COOH), and typical antibiotic, i.e., ciprofloxacin (CIP) were investigated in a batch adsorption experiment. The specific thermodynamic correlation function of PS-COOH combined with CIP was obtained through isothermal titration microcalorimetry (ITC) analysis. The adsorption kinetics and isotherm of CIP on PS-COOH closely fit the pseudo-second-order kinetic model (r2 = 0.99) and Freundlich isotherm (r2 = 0.99). The ITC results showed that the adsorption reaction of PS-COOH with CIP was a spontaneous exothermic reaction. The adsorption of antibiotics on nanoplastics may aggravate the negative impacts of these two pollutants on aqueous ecosystems, and we hypothesized that would be reflected in the survival rate of model organism of Caenorhabditis elegans when exposed to this combination. This work used a mechanistic approach to unravel the adsorption behavior of antibiotics on nanoplastics and shed light on their potential impact on aquatic ecosystems.


Asunto(s)
Plásticos , Contaminantes Químicos del Agua , Adsorción , Ciprofloxacino/toxicidad , Ecosistema , Cinética , Plásticos/toxicidad , Poliestirenos , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/toxicidad
20.
Sci Total Environ ; 750: 142307, 2021 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-33182215

RESUMEN

The pyrolysis of organic feedstock yields the solid fraction biochar, bio-oils, and a volatile fraction that can be reused for energetic purposes or technological applications in agro-ecosystems in the form of smoke-water (SW). In this study, 10 SW types were created from five organic feedstocks (i.e. cellulose, wood sawdust, olive mill residues, maize, and alfalfa litter) at two pyrolysis temperatures (i.e. 300 and 500 °C). We characterized SW using liquid chromatography (LC)-electrospray ionization-time-of-flight (TOF) mass spectrometry (MS) combined with a multi-species bioassay including five crop plants, four fungi, one root-knot nematode (Meloidogyne incognita), and the olive fly pest (Bactrocera oleae). All SW types were acidic, exhibiting a pH range of 1.9-4.6. LC-MS analysis revealed differences in the chemical profiles of SW types in relation to the organic feedstock type and pyrolysis temperature. All SW types exerted concentration-dependent effects on crops, with evident phytotoxic activity at high concentrations. Conversely, they exerted stimulatory effects when diluted with water at ratios ranging from 1:100 to 1:1000. Moreover, all SW types displayed slight or null fungitoxic activity. On the contrary, SW strongly inhibited egg hatching by M. incognita after 72 and 144 h of incubation. The strongest inhibition was found for olive mill SW, and the weakest effect was noted for alfalfa SW. Finally, the application of SW over fresh olives reversed the attraction of B. oleae adults, demonstrating a strong repellent effect toward this pest. Nevertheless, only olive mill SW consistently attracted B. oleae. In conclusion, biochar SW exhibited notable biological activities and potential applications for plant growth promotion, if opportunely diluted, and for the control of root-knot nematodes and olive fruit flies.


Asunto(s)
Nematodos , Agua , Animales , Carbón Orgánico , Ecosistema , Hongos , Humo
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