Potential environmental issues of CO2 storage in deep saline aquifers: Geochemical results from the Frio-I Brine Pilot test,Texas, USA

Sedimentary basins in general, and deep saline aquifers in particular, are being investigated as possible repositories for large volumes of anthropogenic CO₂ that must be sequestered to mitigate global warming and related climate changes. To investigate the potential for the long-term storage of CO₂ in such aquifers, 1600 t of CO₂ were injected at 1500 m depth into a 24-m-thick “C” sandstone unit of the Frio Formation, a regional aquifer in the US Gulf Coast. Fluid samples obtained before CO₂ injection from the injection well and an observation well 30 m updip showed a Na–Ca–Cl type brine with ∼93,000 mg/L TDS at saturation with CH₄ at reservoir conditions; gas analyses showed that CH₄ comprised ∼95% of dissolved gas, but CO₂ was low at 0.3%. Following CO₂ breakthrough, 51 h after injection, samples showed sharp drops in pH (6.5–5.7), pronounced increases in alkalinity (100–3000 mg/L as HCO₃) and in Fe (30–1100 mg/L), a slug of very high DOC values, and significant shifts in the isotopic compositions of H₂O, DIC, and CH₄. These data, coupled with geochemical modeling, indicate corrosion of pipe and well casing as well as rapid dissolution of minerals, especially calcite and iron oxyhydroxides, both caused by lowered pH (initially ∼3.0 at subsurface conditions) of the brine in contact with supercritical CO₂.     

Distribution and mode of occurrence of zinc and lead in glacial soils

The distribution and mode of occurrence of zinc and lead have been examined in glacial soils developed over a complex Precambrian marble-paragneiss terrain in the Adirondack Mountains of New York. Based on distribution within the soil profiles, zinc is enriched in the B₁ horizon of soils sampled over marble and lead is generally enriched in the A horizon, particularly in soils developed over paragneiss. Contrast is calculated using

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, where is the mean of n_A anomalous and n_B background samples, and S_p is the pooled standard deviation) for zinc, lead and cold-extractable heavy metals in soils sampled over marble and paragneiss. The t-values indicate that the B₁, soil horizon is the most suitable for sampling on a regular basis, even though lead is most concentrated in the A horizon.The distribution of zinc and lead among exchangeable, organic, iron-manganese oxide, clay, silt and sand fractions of B₁ horizons from two anomalous and one background soil indicates that both zinc and lead are tied up principally in iron and manganese oxides. The anomalous samples exhibit zinc enrichment in the Fe-oxide digestion and high Mn/Fe ratios for the Mn-oxide digestion (as well as the total analysis). In terms of total contribution to the sample, significant proportions of zinc in the clastic fraction can be attributed to zinc substitution into clays plus the ineffective removal of Fe-oxides by the ammonium oxalate extraction procedure. Lead, on the other hand, occurs in significant concentrations in clay, silt and sand as well as Fe- and Mn-oxides, probably as a trace constituent in feldspars or adsorbed onto clay surfaces.     

Triggering of El Niño by westerly wind events in a coupled general circulation model

Two ten-members ensemble experiments using a coupled ocean-atmosphere general circulation model are performed to study the dynamical response to a strong westerly wind event (WWE) when the tropical Pacific has initial conditions favourable to the development of a warm event. In the reference ensemble (CREF), no wind perturbation is introduced, whereas a strong westerly wind event anomaly is introduced in boreal winter over the western Pacific in the perturbed ensemble (CWWE). Our results demonstrate that an intense WWE is capable of establishing the conditions under which a strong El Niño event can occur. First, it generates a strong downwelling Kelvin wave that generates a positive sea surface temperature (SST) anomaly in the central-eastern Pacific amplified through a coupled ocean-atmosphere interaction. This anomaly can be as large as 2.5°C 60 days after the WWE. Secondly, this WWE also initiates an eastward displacement of the warm-pool that promotes the occurrence of subsequent WWEs in the following months. These events reinforce the initial warming through the generation of additional Kelvin waves and generate intense surface jets at the eastern edge of the warm-pool that act to further shift warm waters eastward. The use of a ten-members ensemble however reveals substantial differences in the coupled response to a WWE. Whereas four members of CWWE ensemble develop into intense El Niño warming as described above, four others display a moderate warming and two remains in neutral conditions. This diversity between the members appears to be due to the internal atmospheric variability during and following the inserted WWE. In the four moderate warm cases, the warm-pool is initially shifted eastward following the inserted WWE, but the subsequent weak WWE activity (when compared to the strong warming cases) prevents to further shift the warm-pool eastwards. The seasonal strengthening of trade winds in June–July can therefore act to shift warm waters back into the western Pacific, reducing the central-eastern Pacific warming. This strong sensitivity of the coupled response to WWEs may therefore limit the predictability of El Niño events, as the high frequency wind variability over the warm pool region remains largely unpredictable even at short time lead.     

Protection of marine birds and turtles at St Brandon’s Rock,Indian Ocean,requires conservation of the entire atoll

A survey of seabirds and turtles at St Brandon’s Rock, 400 km north of Mauritius, was undertaken in 2010. We estimated that 1 084 191 seabirds comprising seven breeding species and excluding non-breeders were present at the archipelago and we counted 279 turtle tracks and nesting pits of green turtles Chelonia mydas. Hawksbill turtles Eretmochelys imbricata were also present. Analyses of 30 different islets that make up the atoll showed that the seabird species mostly partitioned their use of islets based on islet size, with four species preferring larger islets and two species preferring smaller islets. Alien species introduced historically are still present and other threats, such as shipwrecks, remain. We propose conservation and other measures that should adequately protect the birds, turtles and coral reef by treating the atoll as a system.     

Tolerance and Rejection: The Vote on Colorado's Amendment Two

Coloradoapos;s 1992 vote on Amendment Two was the first meaningful, broad-based test of attitudes on gay rights within the United States. Analysis of voting results distinguishes places of tolerance from places of rejection. Social differences separating these places reflect typical contrasts between “traditionalists” and “modernizers” found in cultural conflicts at the national level. Places showing support for gay rights are recreational-based mountain communities, urban areas, and university communities. Those showing opposition are rural, agriculturally based communities. Suburban areas produced a more ambivalent vote.     

Distances from auroral zones to the magnetic and geographic equators

Distance from auroral zone is a fundamental parameter in studies of disturbances produced in the thermosphere and ionosphere through the action of the solar wind. Calculations showing the great variation of the distances of the auroral “zones” from the magnetic equator and geographic equator are presented in diagrams. An auroral zone proximity index is proposed for use in correlative studies of upper atmosphere and of ionospheric disturbances.     

Spatial and temporal patterns of nutrient concentration and export in the tidal Hudson River

Spatial and temporal dynamics of N and P were examined in the tidal Hudson River between 1992 and 1996. For all seasons and at all locations in the river nutrient concentrations were generally quite high. TN averaged 60 μM and was above 50 μM in 75% of samples. TP averaged 1.7 μM and was above 1.2 μM in 75% of samples. NO₃ was the dominant form of N (60% of TN) while PO₄ comprised about 40% of TP. Seasonal and spatial variation in most N and P components was quite low but patterns were apparent. Seasonally, forms of N (TN, NO₃ and NH₄) and PO₄ showed opposite patterns. All N components showed summertime decreases, but PO₄ increased over the summer. Spatially, along the 200 km fresh to oligohaline stretch, N and P showed similar patterns—declining from upper to mid sections of the river but subsequently increasing in most down river, oligohaline stretches. The down river increase in nutrients is likely caused by a combination of sewage inputs and salinity-related geochemical release of P. A preliminary budget of the upper to the mid section of the river (a 100 km stretch) suggests that the decline in nutrient concentration in this section is due to the net retention of almost 2,000 mT N and 200 mT P per year or about 20% of the N and P input to this section of river. The retention in tidal rivers, like the Hudson, occurs immediately above the estuary and may, therefore, be relatively more significant than retention occurring higher in the watershed.