PURPOSE: Cold and hot water processes have been intensively used to recover soil organic matter, but the effect of extraction conditions on the composition of the extracts were not well investigated. Our objective was to optimize the extraction conditions (time and temperature) to increase the extracted carbon efficiency while minimizing the possible alteration of water extractable organic matter of soil (WEOM). METHOD: WEOM were extracted at 20°C, 60°C, or 80°C for 24 h, 10–60 min, and 20 min, respectively. The different processes were compared in terms of pH of suspensions, yield of organic carbon, spectroscopic properties (ultraviolet–visible absorption and fluorescence), and by chromatographic analyses. RESULTS: For extraction at 60°C, the time 30 min was optimal in terms of yield of organic carbon extracted and concentration of absorbing and fluorescent species. The comparison of WEOM 20°C, 24 h; 60°C, 30 min; and 80°C, 20 min highlighted significant differences. The content of total organic carbon, the value of specific ultraviolet absorbance (SUVA254), the absorbance ratio at 254 and 365 nm (E 2/E 3), and the humification index varied in the order: WEOM (20°C, 24 h) < WEOM (80°C, 20 min) < WEOM (60°C, 30 min). The three WEOM contained common fluorophores associated with simple aromatic structures and/or fulvic-like and common peaks of distinct polarity as detected by ultra performance liquid chromatography. CONCLUSIONS: For the soil chosen, extraction at 60°C for 30 min is the best procedure for enrichment in organic chemicals and minimal alteration of the organic matter.

International audience | Cold and hot water processes have been intensively used to recover soil organic matter, but the effect of extraction conditions on the composition of the extracts were not well investigated. Our objective was to optimize the extraction conditions (time and temperature) to increase the extracted carbon efficiency while minimizing the possible alteration of water extractable organic matter of soil (WEOM). WEOM were extracted at 20A degrees C, 60A degrees C, or 80A degrees C for 24 h, 10-60 min, and 20 min, respectively. The different processes were compared in terms of pH of suspensions, yield of organic carbon, spectroscopic properties (ultraviolet-visible absorption and fluorescence), and by chromatographic analyses. For extraction at 60A degrees C, the time 30 min was optimal in terms of yield of organic carbon extracted and concentration of absorbing and fluorescent species. The comparison of WEOM 20A degrees C, 24 h; 60A degrees C, 30 min; and 80A degrees C, 20 min highlighted significant differences. The content of total organic carbon, the value of specific ultraviolet absorbance (SUVA(254)), the absorbance ratio at 254 and 365 nm (E (2)/E (3)), and the humification index varied in the order: WEOM (20A degrees C, 24 h) < WEOM (80A degrees C, 20 min) < WEOM (60A degrees C, 30 min). The three WEOM contained common fluorophores associated with simple aromatic structures and/or fulvic-like and common peaks of distinct polarity as detected by ultra performance liquid chromatography. For the soil chosen, extraction at 60A degrees C for 30 min is the best procedure for enrichment in organic chemicals and minimal alteration of the organic matter.

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present — on the example of teleost fishes — a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens.

Numerous environmental chemicals, both long-known toxicants such as persistent organic pollutants as well as emerging contaminants such as pharmaceuticals, are known to modulate immune parameters of wildlife species, what can have adverse consequences for the fitness of individuals including their capability to resist pathogen infections. Despite frequent field observations of impaired immunocompetence and increased disease incidence in contaminant-exposed wildlife populations, the potential relevance of immunotoxic effects for the ecological impact of chemicals is rarely considered in ecotoxicological risk assessment. A limiting factor in the assessment of immunotoxic effects might be the complexity of the immune system what makes it difficult (1) to select appropriate exposure and effect parameters out of the many immune parameters which could be measured, and (2) to evaluate the significance of the selected parameters for the overall fitness and immunocompetence of the organism. Here, we present - on the example of teleost fishes - a brief discussion of how to assess chemical impact on the immune system using parameters at different levels of complexity and integration: immune mediators, humoral immune effectors, cellular immune defenses, macroscopical and microscopical responses of lymphoid tissues and organs, and host resistance to pathogens. Importantly, adverse effects of chemicals on immunocompetence may be detectable only after immune system activation, e.g., after pathogen challenge, but not in the resting immune system of non-infected fish. Current limitations to further development and implementation of immunotoxicity assays and parameters in ecotoxicological risk assessment are not primarily due to technological constraints, but are related from insufficient knowledge of (1) possible modes of action in the immune system, (2) the importance of intra- and inter-species immune system variability for the response against chemical stressors, and (3) deficits in conceptual and mechanistic assessment of combination effects of chemicals and pathogens.

CO₂ leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO₂ seawater acidification, a bubbling CO₂ system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8.0, 7.5, 7.0, 6.5, 6.0, and 5.5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6.0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p < 0.05) was observed at pH values lower than 6.0. Very high lethal effects (calculating L[H⁺]50, defined as the H⁺ concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO₂ leakages in marine environments.

CO2 leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO2 seawater acidification, a bubbling CO2 system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8. 0, 7. 5, 7. 0, 6. 5, 6. 0, and 5. 5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6. 0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p < 0.05) was observed at pH values lower than 6. 0. Very high lethal effects (calculating L[H+]50, defined as the H+ concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO2 leakages in marine environments. © 2012 Springer-Verlag. | The work described was supported partially by grants from the Spanish Ministry of Science and Innovation (CTM2008-06344-C03-02/ TECNO, CTM2008-06344-C03-03/TECNO, and CTM2011-28437-C02-02) and by grant P08-556 RNM 3924 from the Regional Government of Andalusia (Junta de Andalucía). | Peer Reviewed

Climate change mediates marine chemical and physical environments and therefore influences marine organisms. While increasing atmospheric CO2 level and associated ocean acidification has been predicted to stimulate marine primary productivity and may affect community structure, the processes that impact food chain and biological CO2 pump are less documented. We hypothesized that copepods, as the secondary marine producer, may respond to future changes in seawater carbonate chemistry associated with ocean acidification due to increasing atmospheric CO2 concentration. Here, we show that the copepod, Centropages tenuiremis, was able to perceive the chemical changes in seawater induced under elevated CO2 concentration (>1700 µatm, pH < 7.60) with avoidance strategy. The copepod's respiration increased at the elevated CO2 (1000 µatm), associated acidity (pH 7.83) and its feeding rates also increased correspondingly, except for the initial acclimating period, when it fed less. Our results imply that marine secondary producers increase their respiration and feeding rate in response to ocean acidification to balance the energy cost against increased acidity and CO2 concentration.

Climate change mediates marine chemical and physical environments and therefore influences marine organisms. While increasing atmospheric CO₂ level and associated ocean acidification has been predicted to stimulate marine primary productivity and may affect community structure, the processes that impact food chain and biological CO₂ pump are less documented. We hypothesized that copepods, as the secondary marine producer, may respond to future changes in seawater carbonate chemistry associated with ocean acidification due to increasing atmospheric CO₂ concentration. Here, we show that the copepod, Centropages tenuiremis, was able to perceive the chemical changes in seawater induced under elevated CO₂ concentration (>1700μatm, pH<7.60) with avoidance strategy. The copepod’s respiration increased at the elevated CO₂ (1000μatm), associated acidity (pH 7.83) and its feeding rates also increased correspondingly, except for the initial acclimating period, when it fed less. Our results imply that marine secondary producers increase their respiration and feeding rate in response to ocean acidification to balance the energy cost against increased acidity and CO₂ concentration.

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.

In the study, we establish centennial records of anthropogenic lead pollution at different locations in the North Atlantic (Iceland, USA, and Europe) by means of lead deposited in shells of the long-lived bivalve Arctica islandica. Due to local oceanographic and geological conditions we conclude that the lead concentrations in the Icelandic shell reflect natural influxes of lead into Icelandic waters. In comparison, the lead profile of the US shell is clearly driven by anthropogenic lead emissions transported from the continent to the ocean by westerly surface winds. Lead concentrations in the European North Sea shell, in contrast, are dominantly driven by local lead sources resulting in a much less conspicuous 1970s gasoline lead peak. In conclusion, the lead profiles of the three shells are driven by different influxes of lead, and yet, all support the applicability of Pb/Ca analyses of A. islandica shells to reconstruct location specific anthropogenic lead pollution.