175 research outputs found
Using remote sensing as a support to the implementation of the European Marine Strategy Framework Directive in SW Portugal
The exclusive economic zones (EEZ) of coastal countries are coming under increasing pressure from various economic sectors such as fishing, aquaculture, shipping and energy production. In Europe, there is a policy to expand the maritime economic sector without damaging the environment by ensuring that these activities comply with legally binding Directives, such as the Marine Strategy Framework Directive (MSFD). However, monitoring an extensive maritime area is a logistical and economic challenge. Remote sensing is considered one of the most cost effective, methods for providing the spatial and temporal environmental data that will be necessary for the effective implementation of the MSFD. However, there is still a concern about the uncertainties associated with remote sensed products. This study has tested how a specific satellite product can contribute to the monitoring of a MSFD Descriptor for "good environmental status" (GES). The results show that the quality of the remote sensing product Algal Pigment Index 1 (API 1) from the MEdium Resolution Imaging Spectrometer (MERIS) sensor of the European Space Agency for ocean colour products can be effectively validated with in situ data from three stations off the SW Iberian Peninsula. The validation results show good agreement between the MERIS API 1 and the in situ data for the two more offshore stations, with a higher coefficient of determination (R-2) of 0.79, and with lower uncertainties for the average relative percentage difference (RPD) of 24.6% and 27.9% and a root mean square error (RMSE) of 0.40 and 0.38 for Stations B and C, respectively. Near to the coast, Station A has the lowest R-2 of 0.63 and the highest uncertainties with an RPD of 112.9% and a RMSE of 1.00. It is also the station most affected by adjacency effects from the land: when the Improved Contrast between Ocean and Land processor (ICOL) is applied the R-2 increases to 0.77 and there is a 30% reduction in the uncertainties estimated by RPD. The MERIS API 1 product decreases from inshore to offshore, with higher values occurring mainly between early spring and the end of the summer, and with lower values during winter. By using the satellite images for API 1, it is possible to detect and track the development of algal blooms in coastal and marine waters, demonstrating the usefulness of remote sensing for supporting the implementation of the MSFD with respect to Descriptor 5: Eutrophication. It is probable that remote sensing will also prove to be useful for monitoring other Descriptors of the MSFD.EU (European Space Agency) [308392, 21464/08/1-0, 607325]; Portuguese FCT [FRH/BD/78354/2011, SFRH/BD/78356/2011]; Horizon 2020 AquaSpace [633476]info:eu-repo/semantics/publishedVersio
Avances en ecotoxicología marina: comparación entre tests de laboratorio y estudios in situ para la evaluación de la calidad ambiental de los sedimentos
Ecotoxicology is concerned with describing and predicting the behaviour of substances in the
environment and the response of biological systems, and ultimately with assessing the risks associated
with emissions. These assessments are complicated from a basic-science point of view and they should be
carried out by using integrative assessments. Contaminated sediments are a significant regulatory issue
with important science implications. Determining the impact of contaminated sediments is a key element
in environmental risk assessment and management of water resources. Tests for ecotoxicology
assessment in sediments may be conducted either in the laboratory or field. Both approaches have
advantages and disadvantages. Data from different studies performed in laboratory conditions and in field
assessments are compared here. The principal advantages of sediment toxicity tests in the laboratory are
the possibility to standardize methodologies and to provide direct evidence of sediments as causative
agents of toxicity; however, the results are difficult to extrapolate to the field. The results obtained here
show the importance of the end point selected in each test and the variability of the responses. Therefore,
the results highlight the necessity and importance of the battery-of-tests approach for toxicity assessment.
On the other hand, field sediment toxicity has the advantage of empirical evidence and strong correlative
indication of the contaminants responsible for toxicity; however, the results obtained from these tests are
highly affected by casualty, so it is not possible to isolate a single causative factor. When structural
macrofaunal parameters are incorporated into field tests, the results are even more difficult to interpret,
because their parameters can be mainly related to organic enrichment or another kind of natural stress,
such as salinity gradient, tidal stress conditions, etc.La ecotoxicología es la ciencia que describe y predice el comportamiento de las sustancias en el
medio ambiente y las respuestas biológicas del sistema para así, finalmente, evaluar el riesgo asociado
con estas emisiones. Estas evaluaciones son difíciles de realizar desde el punto de vista científico y
deberían ser elaboradas mediante métodos integrados. Los sedimentos se contemplan, desde el punto de
vista científico, como un componente clave en el ecosistema para la evaluación de la calidad ambiental.
Los tests de toxicidad de los sedimentos se pueden llevar a cabo tanto en el laboratorio como en el medio
teniendo ambos ventajas y desventajas. En este trabajo se comparan los datos obtenidos de distintos
experimentos realizados en el laboratorio y un estudio elaborado en el campo. Las principales ventajas de
los tests que se han llevado a cabo en el laboratorio fueron la posibilidad de estandarizar la metodología y
la evidencia directa que se obtiene de que el sedimento contaminado es el causante de la respuesta
biológica; sin embargo, estos resultados son difíciles de extrapolar a la naturaleza. Los resultados
obtenidos en este estudio muestran también la importancia de la variable seleccionada en cada test así
como la variabilidad en sus respuestas. Por lo tanto, los resultados resaltan la necesidad y la importancia
de la utilización de una batería de tests para la evaluación de la toxicidad. Por otra parte, los estudios
realizados in situ tienen la ventaja de la evidencia empírica y la fuerte indicación entre la correlación de la
toxicidad y los resultados obtenidos; sin embargo, estos resultados están muy afectados por el azar, lo que
imposibilita aislar un único factor causante de la respuesta biológica. Los resultados son incluso más
difíciles de interpretar cuando se realizan índices estructurales de la macrofauna porque éstos pueden
estar más relacionados con el contenido en materia orgánica u otra causa de estrés natural, como puede
ser un gradiente de salinidad producido por la marea, etc.Comisión Interministerial de Ciencia y Tecnología (CICYT) de España. AMB94-029
TAXOMETRICS CLASSIFICATION (HIERARCHICAL AND ORDINATION) OF AQUATIC AND SEMI-AQUATIC MOSSES: A PRELIMINARY MODEL TO BRYODIVERSITY MANAGEMENT
Bryodiversity is naturally serving the ecosystems sustainably. It serves the environments by preventing natural disaster (flooding), maintaining the quality of the water body and filter or treats the pollutants naturally. Efficient bryodiversity management is needed for environmental cost cutting and have a cost-effective management strategy. To achieve this, cluster and principal component analyses (PCA) were manipulated to produce the linkage distance between the OTUs and identify the important groups of characters, respectively. In return, it becomes a guideline for bryoflora and environmental managements. In this study, 23 OTUs and 156 characters were analyzed. The output from the reliability and item analysis showed that the data set is highly reliable (Cronbach’s alpha = 0.9627). From the cluster analysis, it showed that 5 clustered groups (manageable units) could be derived from the produced phenogram. This is based on the nearest neighbour amalgation rule and Euclidean distances. As for the principal component analysis, three factors were derived and explained 75.1064% of the variation with 56.0485%(PC1), 11.7346%(PC2) and 7.3233%(PC3), respectively. The ordination showed that 5 manageable units were derived from PC1 and 3 manageable units for PC2 and PC3, respectively. In conclusion, conservation should precede any biodiversity management plans.  Keywords: aquatic mosses, semi-aquatic mosses, cluster analysis, principal component analysis (PCA), classification Â
Can the integration of multiple biomarkers and sediment geochemistry aid solving the complexity of sediment risk assessment?: a case study with a benthic fish
Surveying toxicity of complex geochemical media as aquatic sediments often yields results that are either
difficult to interpret or even contradictory to acknowledged theory. Multi-level biomarkers were
investigated in a benthic fish exposed to estuarine sediments through laboratory and in situ bioassays, to
evaluate their employment either in ecological risk assessment or in more mechanistic approaches to
assess sediment-bound toxicity. Biomarkers reflecting lesions (such as genotoxicity or histopathology),
regardless of their low or absent specificity to contaminants, are efficient in segregating exposure to
contaminated from uncontaminated sediments even when classical biomarkers like CYP1A and metallothionein induction are inconclusive. Conversely, proteomics and gene transcription analyses provided
information on the mechanics of toxicity and aided explaining response variation as a function of
metabolic imbalance and impairment of defences against insult. In situ bioassays, although less expedite
and more affected by confounding factors, produced data better correlated to overall sediment
contamination.info:eu-repo/semantics/publishedVersio
Estuarine ecological risk based on hepatic histopathological indices from laboratory and in situ tested fish
Juvenile Senegalese soles were exposed through 28-day laboratory and field (in situ) bioassays to sediments
from three sites of the Sado estuary (W Portugal): a reference and two contaminated by metallic
and organic contaminants. Fish were surveyed for ten hepatic histopathological alterations divided by
four distinct reaction patterns and integrated through the estimation of individual histopathological condition
indices. Fish exposed to contaminated sediments sustained more damage, with especial respect to
regressive changes like necrosis. However, differences were observed between laboratory- and fieldexposed
animals, with the latest, for instance, exhibiting more pronounced fatty degeneration and hepatocellular
eosinophilic alteration. Also, some lesions in fish exposed to the reference sediment indicate
that in both assays unaccounted variables produced experimental background noise, such as hyaline
degeneration in laboratory-exposed fish. Still, the field assays yielded results that were found to better
reflect the overall levels of contaminants and physico-chemical characteristics of the tested sediments.info:eu-repo/semantics/publishedVersio
Biochemical endpoints on juvenile Solea senegalensis exposed
Juvenile Solea senegalensis were exposed to
fresh sediments from three stations of the Sado estuary
(Portugal) in 28-day laboratory assays. Sediments revealed
distinct levels of total organic matter, fine fraction, redox
potential, trace elements (arsenic, cadmium, chromium,
copper, nickel, lead and zinc) and organic contaminants
(polycyclic aromatic hydrocarbons, polychlorinated
biphenyls and a pesticide: dichloro diphenyl trichloroethane).
Organisms were surveyed for contaminant bioaccumulation
and induction of two hepatic biochemical
biomarkers: metallothionein (MT) and cytochrome P450
(CYP1A), as potential indicators of exposure to metallic
and organic contaminants, respectively. Using an integrative
approach it was established that, although bioaccumulation
is in general accordance with sediment
contamination, lethality and biomarker responses are not
linearly dependent of the cumulative concentrations of
sediment contaminants but rather of their bioavailability
and synergistic effects in organisms. It is concluded that
metals and organic contaminants modulate both MT and
CYP1A induction and it is suggested that reactive oxygen
species may be the link between responses and effects of
toxicity.peerreviewe
Ecological risk assessment of sediment management areas : application to Sado Estuary, Portugal
The purpose of this work was to integrate different
methodologies to assess the potential ecological risk
of estuarine sedimentary management areas, using the Sado
Estuary in Portugal as case study. To evaluate the environmental
risk of sediment contamination, an integrative
and innovative approach was used involving assessment of
sediment chemistry, sediment toxicity, benthic community
structure, human driving forces and pressures and management
areas organic load levels. The basis for decisionmaking
for overall assessment was a statistical multivariate
analysis appended into a score matrix tables, using a best
expert judgment. The integrated approach allowed to
identify from the 19 management areas analyzed, three
with no risk but other three with high risk to cause adverse
effects in the biota, related with the contaminants analyzed.
The methodologies used showed to be effective as a support
for decision making leading to future estuarine management
recommendations.peerreviewe
Ecotoxicological assessment of sediments from the Santos and São Vicente estuarine system- Brazil
O sedimento representa um importante depósito de contaminantes e uma fonte de contaminação para a cadeia alimentar aquática. Testes de toxicidade usando anfípodos como organismos-teste são empregados para avaliar sedimentos marinhos e estuarinos, juntamente com análises químicas. O presente trabalho tem como objetivo avaliar a qualidade de sedimentos de seis estações situadas no Sistema Estuarino e Portuário de Santos e São Vicente (São Paulo-Brasil), usando testes de toxicidade aguda com sedimento com anfípodos (Tiburonella viscana) e análises químicas de metais, PCB, e PAH. Outros parâmetros do sedimento foram analisados, como carbono orgânico e granulometria. Foram observados níveis de contaminação mais altos na porção interna do estuário onde se localiza o Porto de Santos e a zona industrial. Os testes de toxicidade mostraram resultados adversos significantes para a maioria das amostras testadas, e os sedimentos da porção interna do estuário apresentaram toxicidade mais alta. As análises de componentes principais indicaram uma relação forte entre contaminação do sedimento e toxicidade. As correlações positivas destes fatores nas amostras estudadas foram usadas para estabelecer os pesos das concentrações químicas que estão associadas com os efeitos adversos. Tais análises permitiram estimar valores limiares de efeito para a contaminação de sedimento através de análises multivariadas, identificando os contaminantes associados com o efeito biológico. Estes valores sugeridos são: Cu, 69.0; Pb, 17.4; Zn, 73.3(mg.kg-1); PAHs, 0.5 (mg.kg-1) e PCBs, 0.1 (µg.kg-1).Sediments represent an important repository of pollutants and a source of contamination for the aquatic food web. Toxicity tests using amphipods as test-organisms have been employed in the assessment of marine and estuarine sediments, together with chemical analyses. The present work aimed to evaluate the quality of sediments from six stations situated in the Santos and São Vicente Estuarine and Harbour System (São Paulo - Brazil) using acute whole sediment toxicity tests with amphipods (Tiburonella viscana) and chemical analyses of metals, PCB's, and PAH's. Other sediment parameters, such as organic carbon and grain size distribution were also analysed. Higher contamination levels were observed in the internal portion of the estuary, where Santos harbour and the industrial zone are located. The toxicity tests showed significant adverse results for most of the samples tested, and the sediments from the internal portion of the estuary presented the highest toxicity. The principal component analyses (PCA) indicated a close relationship between sediment contamination and toxicity. Positive correlation of these factors in the samples studied was used to establish the ranges of the chemical concentrations associated with adverse effects. Such ranges allowed the estimation of preliminary effect threshold values for sediment contamination, by means of multivariate analysis. These suggested values are: Cu, 69.0; Pb, 17.4; Zn, 73.3 (mg.kg-1); PAHs, 0.5 (mg.kg-1) and PCBs, 0.1 (µg.kg-1)
Assessment of the genotoxic potential of contaminated estuarine sediments in fish peripheral blood: laboratory versus in situ studies
Juvenile Senegalese soles (Solea senegalensis) were exposed to estuarine sediments through 28-day
laboratory and in situ (field) bioassays. The sediments, collected from three distinct sites (a reference
plus two contaminated) of the Sado Estuary (W Portugal) were characterized for total organic matter,
redox potential, fine fraction and for the levels of metals, polycyclic aromatic hydrocarbons (PAHs) and
organochlorines, namely polychlorinated biphenyls (PCBs) and dichloro diphenyl tricholoethane plus
its main metabolites (DDTs). Genotoxicity was determined in whole peripheral blood by the single-cell
gel electrophoresis (SCGE or ‘‘comet’’) assay and by scoring erythrocytic nuclear abnormalities (ENA).
Analysis was complemented with the determination of lipid peroxidation in blood plasma by the
thiobarbituric acid reactive substances (TBARS) protocol and cell type sorting. The results showed that
exposure to contaminated sediments induced DNA fragmentation and clastogenesis. Still, laboratory
exposure to the most contaminated sediment revealed a possible antagonistic effect between metallic
and organic contaminants that might have been enhanced by increased bioavailability. The laboratory
assay caused a more pronounced increase in ENA whereas a very significant increase in DNA
fragmentation was observed in field-tested fish exposed to the reference sediment, which is likely
linked to increased lipid peroxidation that probably occurred due to impaired access to food. Influence
of natural pathogens was ruled out by unaltered leukocyte counts. The statistical integration of data
correlated lipid peroxidation with biological variables such as fish length and weight, whereas the
genotoxicity biomarkers were more correlated to sediment contamination. It was demonstrated that
laboratory and field bioassays for the risk assessment of sediment contamination may yield different
genotoxicity profiles although both provided results that are in overall accordance with sediment
contamination levels. While field assays may provide more ecologically relevant data, the multiple
environmental variables may produce sufficient background noise to mask the true effects of
contamination.info:eu-repo/semantics/publishedVersio
Genotoxic damage in Solea senegalensis exposed to sediments from the Sado Estuary (Portugal): effects of metallic and organic contaminants
Juvenile Solea senegalensis (Senegalese sole) were exposed to freshly collected sediments from three sites
of the Sado Estuary (West-Portuguese coast) in 28-day laboratory assays in order to assess the ecological
risk from sediment contaminants, by measuring two genotoxicity biomarkers in peripheral blood: the
percentage of Erythrocyte Nuclear Abnormalities (ENA) by use of an adaptation of the micronucleus test,
and the percentage of DNA strand-breakage (DNA-SB) with the Comet assay. Sediments were surveyed for
metallic (Cr, Ni, Cu, Zn, As, Cd and Pb) and organic (PAHs (polycyclic aromatic hydrocarbons), PCBs (polychlorinated biphenyls) and DDTs (dichloro-diphenyl-trichloroethane)) contaminants. Sediments from site
A (farthest from hotspots of contamination) were found to be the least contaminated and weaker inducers
of genotoxic damage, whereas sediments from sites B (urban influence) and C (affected by industrial effluents and agricultural runoffs) were responsible for a very significant increase in both ENA and DNA-SB,
site B being most contaminated with metals and site C mainly with organic pollutants, especially PAHs
and PCBs . Analysis of genotoxic effects showed a strong correlation between the concentrations of PAHs
and PCBs and both biomarkers at sampling times T14 and T28, while the amounts of Cu, As, Cd and Pb
were less strongly correlated, and at T28 only, with ENA and DNA-SB. These results show that organic
contaminants in sediment are stronger and faster acting genotoxic stressors. The results also suggest that
metals may have an inhibitory effect on genotoxicity when interacting with organic contaminants, at least
during early exposure. ENA and DNA-SB do not show a linear relationship, but a strong correlation exists
between the overall increase in genotoxicity caused by exposure to sediment, confirming that they are
different, and possibly non-linked effects that respond similarly to exposure. Although the Comet assay
showed enhanced sensitivity, the two analyses are complementary and suitable for the biomonitoring of
sediment contaminants in a benthic species like S. senegalensis.info:eu-repo/semantics/publishedVersio
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