In situ detection of boron by ChemCam on Mars

We report the first in situ detection of boron on Mars. Boron has been detected in Gale crater at levels Curiosity rover ChemCam instrument in calcium-sulfate-filled fractures, which formed in a late-stage groundwater circulating mainly in phyllosilicate-rich bedrock interpreted as lacustrine in origin. We consider two main groundwater-driven hypotheses to explain the presence of boron in the veins: leaching of borates out of bedrock or the redistribution of borate by dissolution of borate-bearing evaporite deposits. Our results suggest that an evaporation mechanism is most likely, implying that Gale groundwaters were mildly alkaline. On Earth, boron may be a necessary component for the origin of life; on Mars, its presence suggests that subsurface groundwater conditions could have supported prebiotic chemical reactions if organics were also present and provides additional support for the past habitability of Gale crater

Spatiotemporal variability in the O-18-salinity relationship of seawater across the tropical Pacific Ocean

The relationship between salinity and the stable oxygen isotope ratio of seawater (δ18Osw) is of utmost importance to the quantitative reconstruction of past changes in salinity from δ18O values of marine carbonates. This relationship is often considered to be uniform across water masses, but the constancy of the δ18Osw-salinity relationship across space and time remains uncertain, as δ18Osw responds to varying atmospheric vapor sources and pathways, while salinity does not. Here we present new δ18Osw-salinity data from sites spanning the tropical Pacific Ocean. New data from Palau, Papua New Guinea, Kiritimati, and Galápagos show slopes ranging from 0.09 ‰/psu in the Galápagos to 0.32‰/psu in Palau. The slope of the δ18Osw-salinity relationship is higher in the western tropical Pacific versus the eastern tropical Pacific in observations and in two isotope-enabled climate model simulations. A comparison of δ18Osw-salinity relationships derived from short-term spatial surveys and multiyear time series at Papua New Guinea and Galápagos suggests spatial relationships can be substituted for temporal relationships at these sites, at least within the time period of the investigation. However, the δ18Osw-salinity relationship varied temporally at Palau, likely in response to water mass changes associated with interannual El Niño–Southern Oscillation (ENSO) variability, suggesting nonstationarity in this local δ18Osw-salinity relationship. Applying local δ18Osw-salinity relationships in a coral δ18O forward model shows that using a constant, basinwide δ18Osw-salinity slope can both overestimate and underestimate the contribution of δ18Osw to carbonate δ18O variance at individual sites in the western tropical Pacific.We are grateful for the dedicated water samplers who enabled this research: Lori J. Bell and Gerda Ucharm of the Coral Reef Research Foundation, Palau; Rosa Maritza Motoche Gonzalez and the Fuerza Aerea Ecuatoriana, Santa Cruz, Galapagos, Ecuador; Taonateiti Kabiri and the students of Tennessee Primary School, London, Kiritimati; and the Manus Weather Observers, U.S. Department of Energy ARM Climate Research Facility, Manus, Papua New Guinea. We would like to thank the Galapagos National Park, the Kiritimati Ministry of Environment Lands and Agricultural Development for sample permits, and the Charles Darwin Research Station for logistical support. Funding sources for this work includes NSF-AGS-PF 1049664 to J.L.C., NSF P2C2-1203785 to K.M.C., J.L.C., and D.N. This research was also supported by the Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility. Isotope data are available as supporting information associated with the manuscript. (1049664 - NSF-AGS-PF; P2C2-1203785 - NSF; Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility

Economy and Environmental Problems in the Mexican Coastal States

A canonical correspondence analysis (CCA) for environmental and economic variables was performed for 17 Mexican coastal states. The ordination method allowed us to identify three groups, namely hydroelectric energy generation (I), pollution (II) and harbours (III), which were associated to different human activities. Furthermore, CCA is efficient to help us generate hypotheses for future research. It is therefore advised that CCA should be used for routine analyses into economics.Coastal States of Mexico, Canonical Correspondence Analysis, Diversity Index, Economic Development, Environmental Variables.

Three hundred eighty thousand year long stable isotope and faunal records from the Red Sea : influence of global sea level change on hydrography

Stable isotope and faunal records from the central Red Sea show high-amplitude oscillations for the past 380,000 years. Positive δ18O anomalies indicate periods of significant salt buildup during periods of lowered sea level when water mass exchange with the Arabian Sea was reduced due to a reduced geometry of the Bab el Mandeb Strait. Salinities as high as 53‰ and 55‰ are inferred from pteropod and benthic foraminifera δ18O, respectively, for the last glacial maximum. During this period all planktonic foraminifera vanished from this part of the Red Sea. Environmental conditions improved rapidly after 13 ka as salinities decreased due to rising sea level. The foraminiferal fauna started to reappear and was fully reestablished between 9 ka and 8 ka. Spectral analysis of the planktonic δ18O record documents highest variance in the orbital eccentricity, obliquity, and precession bands, indicating a dominant influence of climatically - driven sea level change on environmental conditions in the Red Sea. Variance in the precession band is enhanced compared to the global mean marine climate record (SPECMAP), suggesting an additional influence of the Indian monsoon system on Red Sea climates

Preliminary use of oxygen stable isotopes and the 1983 El Niño to assess the accuracy of aging black rockfish (Sebastes melanops)

Black rockfish (Sebastes melanops) range from California to Alaska and are found in both nearshore and shallow continental shelf waters (Love et al., 2002). Juveniles and subadults inhabit shallow water, moving deeper as they grow. Generally, adults are found at depths shallower than 55 meters and reportedly live up to 50 years. The species is currently managed by using information from an age-structured stock assessment model (Ralston and Dick, 2003)

The effect of temperature and salinity on the stable hydrogen isotopic composition of long chain alkenones produced by <i>Emiliania huxleyi</i> and <i>Gephyrocapsa oceanica</i>

International audienceTwo haptophyte algae, Emiliania huxleyi and Gephyrocapsa oceanica, were cultured at different temperatures and salinities to investigate the impact of these factors on the hydrogen isotopic composition of long chain alkenones synthesized by these algae. Results showed that alkenones synthesized by G. oceanica were on average depleted in D by 30 per mil compared to those of E. huxleyi when grown under similar conditions. The fractionation factor, ?alkenones-H2O, ranged from 0.760 to 0.815 for E. huxleyi and from 0.741 to 0.788 for G. oceanica. There was no significant correlation of ?alkenones-H2O with temperature but a positive linear correlation was observed between ?alkenones-H2O and salinity with ~3 per mil change in fractionation per salinity unit. This suggests that salinity can have a substantial impact on the stable hydrogen isotopic composition of long chain alkenones in natural environments and, vice versa, that ?D can possibly be used as a proxy to estimate paleosalinity

Aplicación de criterios geoquímicos al reconocimiento de medios hipersalinos en los materiales arcillosos terciarios de la Depresión Central Catalana

El efecto de distintos ácidos en la puesta en solución de cationes adsorbidos en los minerales de las arcillas ha sido tratado a menudo, tanto desde el punto de vista del estudio de sedimentos arcillosos como del análisis de elementos traza en carbonatos. En este trabajo se estudia el  comportamiento de algunos cationes frente al lavado con agua destilada y con ácido acético (20 % v/v). Asimismo se comparan las concentraciones de cationes en las soluciones de lavado de sedimentos depositados en medios de distinta salinidad. Se observa que, comparando sedimentos de composición mineralógica parecida, las concentraciones de sodio, potasio, litio y magnesio de muestras depositadas en ambientes hipersalinos son mucho más eleva das que las depositadas en ambientes de salinidad menor

Early to middle Eocene history of the Arctic Ocean from Nd-Sr isotopes in fossil fish debris, Lomonosov Ridge

Strontium and neodymium radiogenic isotope ratios in early to middle Eocene fossil fish debris (ichthyoliths) from Lomonosov Ridge (Integrated Ocean Drilling Program Expedition 302) help constrain water mass compositions in the Eocene Arctic Ocean between ∼55 and ∼45 Ma. The inferred paleodepositional setting was a shallow, offshore marine to marginal marine environment with limited connections to surrounding ocean basins. The new data demonstrate that sources of Nd and Sr in fish debris were distinct from each other, consistent with a salinity-stratified water column above Lomonosov Ridge in the Eocene. The 87Sr/86Sr values of ichthyoliths (0.7079–0.7087) are more radiogenic than Eocene seawater, requiring brackish to fresh water conditions in the environment where fish metabolized Sr. The 87Sr/86Sr variations probably record changes in the overall balance of river Sr flux to the Eocene Arctic Ocean between ∼55 and ∼45 Ma and are used here to reconstruct surface water salinity values. The ɛNd values of ichthyoliths vary between −5.7 and −7.8, compatible with periodic (or intermittent) supply of Nd to Eocene Arctic intermediate water (AIW) from adjacent seas. Although the Norwegian-Greenland Sea and North Atlantic Ocean were the most likely sources of Eocene AIW Nd, input from the Tethys Sea (via the Turgay Strait in early Eocene time) and the North Pacific Ocean (via a proto-Bering Strait) also contributed

Palynomorphs of brackish and marine species in cores from the freshwater Lake Sapanca, NW Turkey

Lake Sapanca, which is located on the Sakarya–Sapanca–İzmit corridor in NW Turkey, is a freshwater lake with numerous fish farms in its catchment. Palynological analyses including non-pollen palynomorphs of a short (38.5 cm) and a longer sediment core (586 cm), taken in the centre of the lake and dated in previous investigations, revealed the presence of brackish and marine palynomorphs. The longer sediment sequence shows the occurrence of Brigantedinium sp., Impagidinium caspienense and Spiniferites cruciformis from the base of the core at c. AD 580 years up to 300 cm depth at shortly after c. AD 910. A similar assemblage, but this time with the additional presence of dinoflagellate thecae and the acritarch, Radiosperma corbiferum, was found in the recent core, especially from AD 1986 until the present. Past connections between the Gulf of İzmit and the Black Sea, via the River Sakarya and Lake Sapanca, could be the origin of these two microfossil assemblages. Accidental re-introduction via fish translocation since the Roman times may have been a additional mechanism. The consequences of the survival of brackish and marine forms in a freshwater lake are discussed in terms of wider euryhalinity than has been suggested for those still poorly known organisms