Characterization of sediment subject or not to anthropogenic activities (Golfo Nuevo, Patagonia Argentina)

Contaminantes orgánicos como el tributilestaño (TBT) son particularmente tóxicos para la fauna marina. El objetivo de este trabajo fue caracterizar un sitio contaminado crónicamente (Muelle Luis Piedrabuena-MLP) y otro sin signos de impacto antrópico (Cerro Avanzado-CA) previo al desarrollo de un experimento para evaluar la respuesta de la comunidad macrobentónica al TBT. Para ello, se colectaron muestras de sedimento (n=3) con un corer (diámetro: 11 cm, altura: 15 cm) y se realizó la determinación de parámetros “in situ”. Los resultados indicaron mayores porcentajes de humedad y materia orgánica en MLP cerca de la superficie (46,7±4,1% y 2,8±0,2% versus 27,0±1,0% y 1,2±0,3% en profundidad, respectivamente), mientras que en CA la distribución de estos parámetros fue homogénea (28,5±1,2% y 1,5±0,1%, respectivamente). Con respecto a los análisis biológicos, la clase Polychaeta fue la más abundante en ambos sitios mientras que Anfípoda y Bivalvia predominaron en MLP y CA, respectivamente.Centro de Investigaciones Geológica

Characterization of sediment subject or not to anthropogenic activities (Golfo Nuevo, Patagonia Argentina)

Contaminantes orgánicos como el tributilestaño (TBT) son particularmente tóxicos para la fauna marina. El objetivo de este trabajo fue caracterizar un sitio contaminado crónicamente (Muelle Luis Piedrabuena-MLP) y otro sin signos de impacto antrópico (Cerro Avanzado-CA) previo al desarrollo de un experimento para evaluar la respuesta de la comunidad macrobentónica al TBT. Para ello, se colectaron muestras de sedimento (n=3) con un corer (diámetro: 11 cm, altura: 15 cm) y se realizó la determinación de parámetros “in situ”. Los resultados indicaron mayores porcentajes de humedad y materia orgánica en MLP cerca de la superficie (46,7±4,1% y 2,8±0,2% versus 27,0±1,0% y 1,2±0,3% en profundidad, respectivamente), mientras que en CA la distribución de estos parámetros fue homogénea (28,5±1,2% y 1,5±0,1%, respectivamente). Con respecto a los análisis biológicos, la clase Polychaeta fue la más abundante en ambos sitios mientras que Anfípoda y Bivalvia predominaron en MLP y CA, respectivamente.Centro de Investigaciones Geológica

The bacterial community structure of hydrocarbon-polluted marine environments as the basis for the definition of an ecological index of hydrocarbon exposure

The aim of this study was to design a molecular biological tool, using information provided by amplicon pyrosequencing of 16S rRNA genes, that could be suitable for environmental assessment and bioremediation in marine ecosystems. We selected 63 bacterial genera that were previously linked to hydrocarbon biodegradation, representing a minimum sample of the bacterial guild associated with this process. We defined an ecological indicator (ecological index of hydrocarbon exposure, EIHE) using the relative abundance values of these genera obtained by pyrotag analysis. This index reflects the proportion of the bacterial community that is potentially capable of biodegrading hydrocarbons. When the bacterial community structures of intertidal sediments from two sites with different pollution histories were analyzed, 16 of the selected genera (25%) were significantly overrepresented with respect to the pristine site, in at least one of the samples from the polluted site. Although the relative abundances of individual genera associated with hydrocarbon biodegradation were generally low in samples from the polluted site, EIHE values were 4 times higher than those in the pristine sample, with at least 5% of the bacterial community in the sediments being represented by the selected genera. EIHE values were also calculated in other oil-exposed marine sediments as well as in seawater using public datasets from experimental systems and field studies. In all cases, the EIHE was significantly higher in oiled than in unpolluted samples, suggesting that this tool could be used as an estimator of the hydrocarbon-degrading potential of microbial communities.Fil: Lozada, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Marcos, Magalí Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Commendatore, Marta G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Gil, Mónica N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Dionisi, Hebe Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Effect of experimental conditions on free-living marine nematodes

Los nematodos han sido ampliamente utilizados para evaluar diferentes tipos de disturbios. El objetivo de este trabajo fue comparar la abundancia de la comunidad de nematodos marinos de vida libre en condiciones in situ y ex situ para evaluar el efecto de las condiciones experimentales en el laboratorio. Para ello, se colectaron muestras de sedimento en 3 sitios del golfo San Jorge (GSJ) y se las incubó en el laboratorio bajo condiciones controladas de luz, aire y temperatura, durante 45 días. Al finalizar este período, se analizaron cinco muestras del tratamiento ex situ y se colectaron otras cinco muestras in situ en los sitios estudiados. Luego se comparó la abundancia de nematodos y las características de los sedimentos entre ambos sets de muestras. Los resultados mostraron que existe un efecto de las condiciones de laboratorio sobre la fauna de nematodos y éste es más evidente en las muestras provenientes de sitios sin historia previa de contaminación, como es el caso de PG.Centro de Investigaciones Geológica

Effect of experimental conditions on free-living marine nematodes

Los nematodos han sido ampliamente utilizados para evaluar diferentes tipos de disturbios. El objetivo de este trabajo fue comparar la abundancia de la comunidad de nematodos marinos de vida libre en condiciones in situ y ex situ para evaluar el efecto de las condiciones experimentales en el laboratorio. Para ello, se colectaron muestras de sedimento en 3 sitios del golfo San Jorge (GSJ) y se las incubó en el laboratorio bajo condiciones controladas de luz, aire y temperatura, durante 45 días. Al finalizar este período, se analizaron cinco muestras del tratamiento ex situ y se colectaron otras cinco muestras in situ en los sitios estudiados. Luego se comparó la abundancia de nematodos y las características de los sedimentos entre ambos sets de muestras. Los resultados mostraron que existe un efecto de las condiciones de laboratorio sobre la fauna de nematodos y éste es más evidente en las muestras provenientes de sitios sin historia previa de contaminación, como es el caso de PG.Centro de Investigaciones Geológica

Effect of experimental conditions on free-living marine nematodes

Los nematodos han sido ampliamente utilizados para evaluar diferentes tipos de disturbios. El objetivo de este trabajo fue comparar la abundancia de la comunidad de nematodos marinos de vida libre en condiciones in situ y ex situ para evaluar el efecto de las condiciones experimentales en el laboratorio. Para ello, se colectaron muestras de sedimento en 3 sitios del golfo San Jorge (GSJ) y se las incubó en el laboratorio bajo condiciones controladas de luz, aire y temperatura, durante 45 días. Al finalizar este período, se analizaron cinco muestras del tratamiento ex situ y se colectaron otras cinco muestras in situ en los sitios estudiados. Luego se comparó la abundancia de nematodos y las características de los sedimentos entre ambos sets de muestras. Los resultados mostraron que existe un efecto de las condiciones de laboratorio sobre la fauna de nematodos y éste es más evidente en las muestras provenientes de sitios sin historia previa de contaminación, como es el caso de PG.Centro de Investigaciones Geológica

Oil spill effects on macrofaunal communities and bioturbation of pristine marine sediments (Caleta Valdés, Patagonia, Argentina): experimental evidence of low resistance capacities of benthic systems without history of pollution

The Patagonian coast is characterized by the existence of pristine ecosystems which may be particularly sensitive to oil contamination. In this study, a simulated oil spill at acute and chronic input levels was carried out to assess the effects of contamination on the macrobenthic community structure and the bioturbation activity of sediments sampled in Caleta Valdés creek. Superficial sediments were either noncontaminated or contaminated by Escalante crude oil and incubated in the laboratory for 30 days. Oil contamination induced adverse effects on macrobenthic community at both concentrations with, for the highest concentration, a marked decrease of approximately 40 and 55%of density and specific richness, respectively. Besides the disappearance of sensitive species, some other species like Oligochaeta sp. 1, Paranebalia sp., and Ostracoda sp. 2 species have a higher resistance to oil contamination. Sediment reworking activity was also affected by oil addition. At the highest level of contamination, nearly no activity was observed due to the high mortality of macroorganisms. The results strongly suggest that an oil spill in this protected marine area with no previous history of contamination would have a deep impact on the non-adapted macrobenthic community

Fate of petroleum hydrocarbons in bioturbated pristine sediments from Caleta Valdés (Patagonia Argentina): An ex situ bioassay

Petroleum can pollute pristine shorelines as a consequence of accidental spills or chronic leaks. In this study, the fate of petroleum hydrocarbons in soft pristine sediment of Caleta Valdés (Argentina) subject toex situsimulated oil pollution was assessed. Sedimentary columns were exposed to medium and high concentrations of Escalante Crude Oil (ECO) and incubated in the laboratory during 30 days. Levels of aliphatic hydrocarbons at different depths of the sedimentary column were determined by gas chromatography. Oil penetration was limited to the first three centimetres in both treatments, and under this depth, hydrocarbons were clearly biogenic (terrestrial plants) as in the whole sedimentary column of the control assay. Bioturbation by macrobenthic infauna was strongly impacted by oil pollution which resulted in reduced sediment oxygenation and low burial of petroleum hydrocarbons. This may partly explain the limited hydrocarbon biodegradation observed, as indicated by the relatively high values of the ratios nC17/pristane,nC18/phytane, and total resolved aliphatic hydrocarbons/ unresolved complex mixture. Correspondingly, at the end of the experiment the most probable number of hydrocarbon-degrading bacteria reached ~ 10^3 MPN g−1 dry weight. These values were lower than those found in chronically polluted coastal sediments, reflecting a low activity level of the oil-degrading community. The results highlight the low attenuation capacities of Caleta Valdés pristine sediments to recover its original characteristics in a short time period if an oil spill occurs. In this work, we present a novel and integrative tool to evaluate the fate of petroleum hydrocarbons and their potential damage on pristine sediments

Canagliflozin and Cardiovascular and Renal Outcomes in Type 2 Diabetes Mellitus and Chronic Kidney Disease in Primary and Secondary Cardiovascular Prevention Groups

Background: Canagliflozin reduces the risk of kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, but effects on specific cardiovascular outcomes are uncertain, as are effects in people without previous cardiovascular disease (primary prevention). Methods: In CREDENCE (Canagliflozin and Renal Events in Diabetes With Established Nephropathy Clinical Evaluation), 4401 participants with type 2 diabetes mellitus and chronic kidney disease were randomly assigned to canagliflozin or placebo on a background of optimized standard of care. Results: Primary prevention participants (n=2181, 49.6%) were younger (61 versus 65 years), were more often female (37% versus 31%), and had shorter duration of diabetes mellitus (15 years versus 16 years) compared with secondary prevention participants (n=2220, 50.4%). Canagliflozin reduced the risk of major cardiovascular events overall (hazard ratio [HR], 0.80 [95% CI, 0.67-0.95]; P=0.01), with consistent reductions in both the primary (HR, 0.68 [95% CI, 0.49-0.94]) and secondary (HR, 0.85 [95% CI, 0.69-1.06]) prevention groups (P for interaction=0.25). Effects were also similar for the components of the composite including cardiovascular death (HR, 0.78 [95% CI, 0.61-1.00]), nonfatal myocardial infarction (HR, 0.81 [95% CI, 0.59-1.10]), and nonfatal stroke (HR, 0.80 [95% CI, 0.56-1.15]). The risk of the primary composite renal outcome and the composite of cardiovascular death or hospitalization for heart failure were also consistently reduced in both the primary and secondary prevention groups (P for interaction >0.5 for each outcome). Conclusions: Canagliflozin significantly reduced major cardiovascular events and kidney failure in patients with type 2 diabetes mellitus and chronic kidney disease, including in participants who did not have previous cardiovascular disease

Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years