Soil biology and warming play a key role in the release of ‘old C’ from organic soils

A radiocarbon approach was used to investigate the roles of temperature and soil fauna activity in the turnover of ‘old’ non-labile carbon in a peatland ecosystem. We investigated the impacts of enchytraeids on carbon turnover in two different soil layers, with different incorporation of the ‘bomb’ peak, when incubated at two different temperatures. Results showed that, in agreement with previous studies, warmer temperatures promoted reproduction rates of enchytraeids, with the top layer supporting higher animal densities and biomass. With independence of the animal treatment, soil respiration in the top 5 cm was four times higher than in the deeper layer suggesting that decomposition was greater in the upper layer, with the response being greater at the highest temperature treatment. Furthermore, independent of temperature, the presence of enchytraeids in the top layer significantly enhanced the release of non-labile C as DOC. Similarly, at the bottom layer, ‘older’ C sources were mobilised in response to warming and a greater amount of pre-bomb carbon was released into the soil solution at 20 °C when the worms were present. A strong positive link between the ages of the C assimilated by the animals and released through mineralization suggests an important role of soil biology in the mobilisation of the older C pools in soils and should be taken into account in developing global C models to predict the response of soil C dynamics to climate change.     

Glacial to Interglacial Fluctuations in Productivity in the Equatorial Pacific as Indicated by Marine Barite

An empirical correlation between marine barite (BaSO4) accumulation rate in core-top sediment samples from two equatorial Pacific transects (at 140°W and 110°W) and the estimated primary productivity of the overlying water column were used to evaluate glacial to interglacial changes in productivity. Fluctuations in barite accumulation rates down-core indicate that during glacial periods of the past 450,000 years, the productivity in the central and eastern equatorial Pacific was about two times that during intervening interglacial periods. This result is consistent with other evidence that productivity was high in the eastern and central equatorial Pacific during the last glacial.     

Differential Rotation and Dynamics of the Solar Interior

Splitting of the sun's global oscillation frequencies by large-scale flows can be used to investigate how rotation varies with radius and latitude within the solar interior. The nearly uninterrupted observations by the Global Oscillation Network Group (GONG) yield oscillation power spectra with high duty cycles and high signal-to-noise ratios. Frequency splittings derived from GONG observations confirm that the variation of rotation rate with latitude seen at the surface carries through much of the convection zone, at the base of which is an adjustment layer leading to latitudinally independent rotation at greater depths. A distinctive shear layer just below the surface is discernible at low to mid-latitudes.     

Assessment of Mercury Levels in Soils,Waters, Bottom Sediments and Fishes of Acre State in Brazilian Amazon

Mercury in the aquatic biota and geologic materials in areas without anthropogenic sources has been stimulating the discussion about the possibility of natural Hg occurrence in the Amazon region. In this study the dispersion of Hg in different geologic materials as well as its relationship with high Hg levels, detected in some species of carnivorous fish consumed in the Rio Branco city, is evaluated. Bottom and suspended sediments, river water and fishes were sampled in the Acre and Purus Rivers and in some of their tributaries. Total mercury as well as physical and chemical characterization of the waters were done. Hg on top soil and upper horizons samples were also determined to evaluate the potential Hg accumulation in these materials. In addition the dominant minerals were determined by X-ray Diffraction analysis. Furthermore, ten samples of fossilized material were analyzed. The Hg analysis were carried out by CVAAS. The Hg mean levels in the bottom and suspensed sediments were 0.042 and 0.060 μg g^-1, respectively. In the river water samples, the Hg levels were below the detection limit. The Hg mean values in the different soil samples were as follow: soil samples (0.077 μ g^-1), lower (50–60 cm depth) horizons samples (0.117 μ g^-1), ferruginous nodules within the clayey matrix (0.190 μ g^-1) and fossilized material (0.379 μ g^-1). In the fishes the Hg levels are high with mean of the 1.287 μ g^-1 in the carnivorous species. These levels indicate a possible bioaccumulation of Hg mostly in the carnivorous fishes. Although low concentrations of Hg were found in the river waters, it is assumed here that the bioavailable Hg can is original large from the ferruginousnodules and fossilized materials.     

Nutritional potential of raw and free alpha-galactosides lupin (Lupinus albus Var. multolupa) seed flours. Effect of phytase treatment on nitrogen and mineral dialyzability

The effect of the removal of alpha-galactosides from Lupinus albus L. var. multolupa on the chemical composition of the prepared flour and the dialyzability of N, total P, Ca, Mg, Fe, Zn, and Mn was studied. The extraction process caused a significant increase in total and insoluble nitrogen contents and decreased the amount of soluble protein nitrogen. However, neither these changes nor treatment with phytase seemed to considerably affect in vitro protein digestibility. Except for Ca and Cu, total mineral contents were significantly reduced by the extraction process. The process also caused a significant reduction in the dialyzability of all the minerals studied except P. The decrease in mineral dialyzability was partially counteracted by phytase treatment in amounts of 250-500 phytase units/kg of lupin flour. In the case of Fe, mineral dialyzability did not differ significantly between the two lupin flours studied with treatment with 500 phytase units/kg. Zinc dialyzability was the most efficiently improved by phytase treatment (P < 0.0001), followed by P, Fe, and Mn, and finally by Ca and Mg (P < 0.05).     

Effect of the addition of wine distillery wastes to vineyard soils on the adsorption and mobility of fungicides

In the present work, a study was made of the effect of the addition of liquid and solid wine distillery wastes (WLW and WSW) to vineyard soils on the adsorption and leaching of penconazole and metalaxyl, two fungicides of different hydrophobic character that are widely used in vine cultivation. The study of these processes is of great interest, since currently the green filter system is implemented simultaneously in vine cultivation and as an alternative to classic purification methods of such organic wastes. Three vineyard soils selected from the La Rioja region (NW Spain) were used. Adsorption isotherms of the 14C-labeled fungicides by the soils in aqueous medium and in WLW medium were obtained, together with the percolation curves of the fungicides in packed soil columns under saturated flow conditions. The adsorption and leaching of metalaxyl in a soil amended with WSW were also studied. The Freundlich Kf constants indicated an increase in the adsorption of both fungicides by the soils in WLW medium as compared to aqueous medium. The amounts of penconazole leached in the three soils when they were washed with water and WLW ranged between 3.18 and 39.3% and between 2.00 and 10.4%, respectively, of the total fungicide added to the columns. In the case of metalaxyl, these amounts represented 69.1-100 and 91.6-117%. Variations were also observed in the shape and parameters of the breakthrough curves obtained in both systems and in the presence of WSW. The soluble organic compounds of WLW must be retained by the soil components, creating new adsorbent hydrophobic surfaces, which increase the retention in the soil of the highly hydrophobic compound penconazole. In the case of metalaxyl, which is very water soluble, the soluble organic compounds of WLW seem to contribute to the increase in its leaching, whereas the WSW favors the opposite effect. The results obtained, indicating modifications in the adsorption and leaching of penconazole and metalaxyl in the presence of WLW and WSW, show that further studies should be carried out on the adsorption and mobility of the fungicides in soils from the vineyard zone, which in turn are used as a green filter purification system of wine wastes.     

Engineered in situ bioremediation of soil and groundwater polluted with weathered hydrocarbons

In this work, we present our experience in the engineered in situ biostimulation of a hydrocarbon-polluted subsoil of an old metal-working plant. The site had a long history of fuel, lubricant oil, and diesel spills and leakages that were initially treated by means of physico-chemical techniques. After one year of treatment, weathered hydrocarbons were firmly sorbed in the unsaturated zone, limiting the effectiveness of the physico-chemical methods being applied. Also, low nutrient and dissolved oxygen levels limited natural attenuation yields. Therefore, a bioremediation approach based on the injection of hydrogen peroxide, an oleophilic fertilizer, and a surfactant was applied. Total petroleum hydrocarbons and gas chromatography-mass spectrometry determinations were performed as a chemical means of monitoring the process. Microbial populations, including the presence of hydrocarbon-degrading bacteria, were simultaneously analyzed during the process, using enrichment techniques and confocal laser scanning microscopy observations with fluorescent indicators. Hydrocarbon-degrading bacteria were already present in the polluted subsoil prior to the implementation of this bioremediation technique and increased noticeably during the first 2 months of treatment. Hence, the suitability of the nutrient and oxygen amending approach was confirmed as further demonstrated by chemical determinations.     

ULTRASONOGRAPHIC ASSESSMENT OF METALLIC CLIP CAROTID ANASTOMOSIS IN SHEEP

The aim of this study was to use ultrasonography to assess an experimental carotid arteriotomy followed by end-to-end anastomosis in the lamb. Animals were subjected to an experimental surgical procedure consisting of a right carotid artery arteriotomy and subsequent end-to-end anastomosis with nonpenetrating metallic clips. Left side arteries were used as control. Duplex ultrasonography was performed postoperatively to assess the evolution of the experimental anastomosis. Measurements were made on the right carotid to assess blood flow, peak systolic velocity, and end diastolic velocity, as well as arterial diameter. Animals were periodically checked during the six-month postoperative period. Operated vessels appeared normal during follow up, with pulsatile movements and size similar to non operated carotid arteries. A hyperechoic band, perpendicular to the vessel main axis, was seen on the longitudinal image in operated arteries, but not in the control group. This band corresponded to the anastomosis area, where the clips were positioned. No image suggestive of thrombosis was observed in any operated artery, and blood flow was maintained through the experiment. Finally, a decrease of vessel lumen diameter was evidenced at the level of the anastomosis during the first 30 postoperative days, but it was not present after the 90th postsurgical day. Duplex ultrasonography is a useful imaging technique for the assessment of anatomical details, acoustical properties of the vascular lumen, and study of the intimal surface and vessel wall in growing arteries subjected to surgery. Metallic clips as suturing technique in arterial anastomosis allow for normal vascular growth, as shown by the evolution of flow velocity and vessel diameter.