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Soil invertebrates as bioindicators of urban soil quality
2012
Santorufo, Lucia | Van Gestel, Cornelis A.M. | Rocco, Annamaria | Maisto, Giulia
This study aimed at relating the abundance and diversity of invertebrate communities of urban soils to chemical and physical soil characteristics and to identify the taxa most sensitive or tolerant to soil stressors. The invertebrate community of five urban soils in Naples, Italy, was sampled. To assess soil quality invertebrate community indices (Shannon, Simpson, Menhinick and Pielou indices), Acarina/Collembola ratios, and the soil biological quality index (QBS) were calculated. The chemical and physical characteristics of the soils strongly differed. Abundance rather than taxa richness of invertebrates were more affected by soil characteristics. The community was more abundant and diverse in the soils with high organic matter and water content and low metal (Cu, Pb, Zn) concentrations. The taxa more resistant to the urban environment included Acarina, Enchytraeids, Collembola and Nematoda. Collembolans appeared particularly sensitive to changing soil properties. Among the investigated indices, QBS seems most appropriate for soil quality assessment.
Afficher plus [+] Moins [-]Temporal and spatial trends of perfluoroalkyl substances in liver of roe deer (Capreolus capreolus)
2012
Falk, Sandy | Brunn, Hubertus | Schröter-Kermani, Christa | Failing, Klaus | Georgii, Sebastian | Tarricone, Kathrin | Stahl, Thorsten
For more than 50 years perfluoroalkyl substances (PFASs) have found worldwide industrial and household uses. Some PFASs are presumed to be persistent and bioaccumulative. Roe deer (Capreolus capreolus) are thought to be a suitable bioindicator for the accumulation of organic xenobiotics. Due to the ubiquitous nature of PFASs in the environment a retrospective study on temporal trends was carried out. A total of 110 deer liver pools collected from 1989 to 2010 in Germany were analyzed for their levels of PFASs. The highest concentrations were measured for perfluorooctane sulfonate (PFOS) (median 6.3 μg/kg). Perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were detected with median concentrations of 0.5 μg/kg, 1.2 μg/kg and 0.3 μg/kg, respectively, while concentrations of the other PFASs were below the limit of quantification. PFOS concentrations decreased significantly (rₛ = −0.741; p = <0.0001) from 9.2 μg/kg in 2000 to 1.8 μg/kg in 2010.
Afficher plus [+] Moins [-]Field assessment of a snap bean ozone bioindicator system under elevated ozone and carbon dioxide in a free air system
2012
Burkey, Kent O. | Booker, Fitzgerald L. | Ainsworth, Elizabeth A. | Nelson, Randall L.
Ozone-sensitive (S156) and -tolerant (R123 and R331) genotypes of snap bean (Phaseolus vulgaris L.) were tested as a plant bioindicator system for detecting O₃ effects at current and projected future levels of tropospheric O₃ and atmospheric CO₂ under field conditions. Plants were treated with ambient air, 1.4× ambient O₃ and 550 ppm CO₂ separately and in combination using Free Air Concentration Enrichment technology. Under ambient O₃ concentrations pod yields were not significantly different among genotypes. Elevated O₃ reduced pod yield for S156 (63%) but did not significantly affect yields for R123 and R331. Elevated CO₂ at 550 ppm alone did not have a significant impact on yield for any genotype. Amelioration of the O₃ effect occurred in the O₃ + CO₂ treatment. Ratios of sensitive to tolerant genotype pod yields were identified as a useful measurement for assessing O₃ impacts with potential applications in diverse settings including agricultural fields.
Afficher plus [+] Moins [-]Razorbills (Alca torda) as bioindicators of mercury pollution in the southwestern Mediterranean
2012
Espín, Silvia | Martínez-López, Emma | Gómez-Ramírez, Pilar | María-Mojica, Pedro | García-Fernández, Antonio J.
Levels of mercury (Hg) were analyzed in the tissues of 50 Razorbills (Alca torda), from the Mediterranean area, which had drowned in fishing nets. The mercury distribution pattern in tissues was similar to those of other studies (liver>feather vane>kidney>muscle>brain>feather shaft), with mercury concentrations of 2.85±0.90, 2.66±1.60, 2.23±0.87, 1.54±0.54, 1.48±0.54 and 1.30±0.76mg/kg (dry weight), respectively. It could be considered that Razorbills in the southwestern Mediterranean were chronically exposed to relatively low levels of MeHg, probably below 0.5ppm, via dietary intake. We have proposed prediction equations for brain and kidney Hg concentrations using feather shafts as non-invasive samples. This work provides a solid understanding of Razorbill Hg exposure both in their wintering and breeding grounds, and shows that this species can be useful for assessing marine environmental health in the Mediterranean area.
Afficher plus [+] Moins [-]Spatial distribution of intertidal sandy beach polychaeta along an estuarine and morphodynamic gradient in an eutrophic tropical bay
2012
Omena, E.P. | Lavrado, H.P. | Paranhos, R. | Silva, T.A.
The spatial distribution of polychaeta along pollution gradients often reflects different degrees of disturbance. In order to evaluate polychaeta fauna of an organically polluted tropical bay, 20 sandy beaches distributed in five areas were sampled. The relationship between community structure, slope, beach index, exposure, sediment and water quality parameters were analysed. Multivariate analysis of variance (PERMANOVA) showed differences among areas and beaches. Scolelepis chilensis dominated at mouth of bay beaches whereas Streblospio gynobranchiata and Capitella capitata complex, at inner beaches. Highest polychaete density was recorded at areas 3 and 5 with the dominance of Saccocirrus sp. and the organic indicator species C. capitata complex and Polydora sp. The most important factors obtained from canonical analysis were sorting, slope, mud and organic matter percentage. Marine biotic index (AMBI) showed that areas 3 and 5 were highly affected by anthropogenic factors, given that a poor polychaeta fauna, dominated by opportunistic species, were found. Polychaete assemblages were affected by eutrophication along an estuarine gradient as well as by morphodynamic condition of the beaches.
Afficher plus [+] Moins [-]Evaluation of bacteriological and nutrient concerns in nearshore waters of a barrier island community in SW Florida
2012
Thompson, Mark | Milbrandt, Eric | Bartleson, Richard | Rybak, Alex
To determine if local onsite treatment systems affect nearshore water quality, seasonal and rain event monitoring of bacteria and nitrogen was conducted on the Gulf and estuary sides of Captiva Island. Monitoring wells were used to examine the relationship between surface water and groundwater quality. Nitrates were found to be significantly greater in ground water samples from the areas of Captiva using onsite treatment compared to areas with sewer. However, groundwater enterococci were no greater in areas with onsite treatment. Surface water nitrogen was significantly greater near onsite systems than areas with sewer, linking groundwater and surface water quality. Surface water enterococci increased significantly after rain events. Study results indicated stormwater runoff disperses indicator bacteria from diffuse terrestrial sources into nearshore waters, elevating the concentrations. This study reveals local onsite treatment systems produce elevated surface water nitrogen levels but do not contribute to elevated indicator bacteria concentrations in this system.
Afficher plus [+] Moins [-]Symbiont-specific responses in foraminifera to the herbicide diuron
2012
van Dam, Joost W. | Negri, Andrew P. | Mueller, Jochen F. | Uthicke, Sven
The effects of the photosystem II (PSII) herbicide diuron was assessed on thirteen tropical foraminifera hosting diatom, dinoflagellate, red or green algae endosymbionts. Inhibition of photosynthesis (reduced ΔF/Fₘ ′) by diuron depended on both symbiont type and test ultrastructure, with greatest sensitivity observed for diatom- and chlorophyte-hosting species (24h IC₂₅ 2.5–4μgL⁻¹). Inhibition kinetics was slow (24–48h until maximum inhibition) in comparison with corals, suggesting structural differences may influence herbicide uptake and transport. Although foraminifera were generally less sensitive to direct effects of diuron (inhibition ΔF/Fₘ ′) than other marine phototrophs, damage to PSII (reduction Fᵥ/Fₘ) occurred at concentrations lower than observed for other organisms (24h IC₂₅ 3–12μgL⁻¹). Damage to PSII was highly light dependent and occurred at very low light intensities indicating limited photoprotective capacity. The high diversity, widespread occurrence and relative sensitivity make foraminifera good bioindicator organisms to evaluate phytotoxic stress on coral reefs.
Afficher plus [+] Moins [-]Oxidative stress responses and biological indices in the giant clam Tridacna maxima and the reef fish Epinephelus merra from the French Polynesian Moorea Island
2012
Métais, Isabelle | Ekouma, Elsa Mengue | Ngpan, Romina | Planes, Serge | Mouneyrac, Catherine
Responses of biological indices and oxidative stress biomarkers were studied in the giant clam Tridacna maxima and in the fish Epinephelus merra collected from two sites differing by their level of contamination in the French Polynesian Moorea island. Higher levels of catalase (CAT), glutathione-S-transferases (GST) and thiobarbituric acid reactive substances (TBARs) were observed in the hepatopancreas of T. maxima and in the liver of E. merra compared to muscle. CAT and TBARs levels were significantly higher in the hepatopancreas of clams collected from the impacted site (Vaiare) compared to the reference site (bay of Cook). The same pattern was observed for TBARs levels in the liver of E. merra. These results indicate that both organisms from the impacted site were exposed to contaminants leading to an oxidative stress and demonstrate, for the first time, the usefulness of T. maxima and E. merra as sentinel species for biomonitoring reef environments.
Afficher plus [+] Moins [-]Do human activities affect the picoplankton structure of the Ahe atoll lagoon (Tuamotu Archipelago, French Polynesia)?
2012
Bouvy, Marc | Dupuy, Christine | Pagano, Marc | Barani, Aude | Charpy, Loïc
The spatial variations of the picoplankton (photoautotrophic and heterotrophic microorganisms) in the Ahe atoll lagoon were studied in May and October 2008 to assess whether they were affected by human activities along the atoll. Spatial patterns were studied using 10 sampling stations chosen according to the location of the anthropogenic activities (pearl farming, harbor). Experiments were also carried out to determine whether bacterial growth, with or without predators, was limited by inorganic (N and P) substrates. The results showed that heterotrophic bacterioplankton abundance was superior to the photoautotrophic organisms, especially in May. Significant increases in bacterial abundance were observed in May after 24h incubation with +P and +N (but not in October). All samples complied with the quality levels for fecal indicator bacteria (FIB) defined by the European Union and there was no evidence that human sewage had any impact on picoplankton over the whole atoll.
Afficher plus [+] Moins [-]Faecal Indicator Bacteria: Groundwater Dynamics and Transport Following Precipitation and River Water Infiltration
2012
Faecal contamination of drinking water extracted from alluvial aquifers can lead to severe problems. River water infiltration can be a hazard for extraction wells located nearby, especially during high discharge events. The high dimensionality of river–groundwater interaction and the many factors affecting bacterial survival and transport in groundwater make a simple assessment of actual water quality difficult. The identification of proxy indicators for river water infiltration and bacterial contamination is an important step in managing groundwater resources and hazard assessment. The time resolution of microbial monitoring studies is often too low to establish this relationship. A proxy-based approach in such highly dynamic systems requires in-depth knowledge of the relationship between the variable of interest, e.g. river water infiltration, and its proxy indicator. In this study, continuously recorded physico-chemical parameters (temperature, electrical conductivity, turbidity, spectral absorption coefficient, particle density) were compared to the counts for faecal indicator bacteria, Escherichia coli and Enterococcus sp. obtained from intermittent sampling. Sampling for faecal indicator bacteria was conducted on two temporal scales: (a) routine bi-weekly monitoring over a month and (b) intense (bi-hourly) event-based sampling over 3 days triggered by a high discharge event. Both sampling set-ups showed that the highest bacterial concentrations occurred in the river. E. coli and Enterococcus sp. concentrations decreased with time and length of flow path in the aquifer. The event-based sampling was able to demonstrate differences in bacterial removal between clusters of observation wells linked to aquifer composition. Although no individual proxy indicator for bacterial contamination could be established, it was shown that a combined approach based on time-series of physico-chemical parameters could be used to assess river water infiltration as a hazard for drinking water quality management.
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