Climate Change and Global Wine Quality

From 1950 to 1999 the majority of the world's highest quality wine-producing regions experienced growing season warming trends. Vintage quality ratings during this same time period increased significantly while year-to-year variation declined. While improved winemaking knowledge and husbandry practices contributed to the better vintages it was shown that climate had, and will likely always have, a significant role in quality variations. This study revealed that the impacts of climate change are not likely to be uniform across all varieties and regions. Currently, many European regions appear to be at or near their optimum growing season temperatures, while the relationships are less defined in the New World viticulture regions. For future climates, model output for global wine producing regions predicts an average warming of 2 ^∘C in the next 50 yr. For regions producing high-quality grapes at the margins of their climatic limits, these results suggest that future climate change will exceed a climatic threshold such that the ripening of balanced fruit required for existing varieties and wine styles will become progressively more difficult. In other regions, historical and predicted climate changes could push some regions into more optimal climatic regimes for the production of current varietals. In addition, the warmer conditions could lead to more poleward locations potentially becoming more conducive to grape growing and wine production.     

Dissolution of hausmannite (Mn3O4) in the presence of the trihydroxamate siderophore desferrioxamine B

That microbial siderophores may be mediators of Mn(III) biogeochemistry is suggested by recent studies showing that these well known Fe(III)-chelating ligands form very stable Mn(III) aqueous complexes. In this study, we examine the influence of desferrioxamine B (DFOB), a trihydroxamate siderophore, on the dissolution of hausmannite, a mixed valence Mn(II, III) oxide found in soils and freshwater sediments. Batch dissolution experiments were conducted both in the absence (pH 4-9) and in the presence of 100 μM DFOB (pH 5-9). In the absence of the ligand, there is a sharp decrease in the extent of proton-promoted dissolution above pH 5 and no appreciable dissolution above pH 8. The resulting aqueous Mn²⁺ activities were in good agreement with previous studies, indirectly supporting the accepted two-step mechanism involving the formation of manganite and reprecipitation of hausmannite. Desferrioxamine B enhanced hausmannite dissolution over the entire pH range investigated, both via the formation of a Mn(III) complex and through surface-catalyzed reductive dissolution. Above pH 8, non-reductive ligand-promoted dissolution dominated, whereas below pH 8, dissolution was non-stoichiometric with respect to DFOB. Concurrent proton-promoted, ligand-promoted, reductive, and induced dissolution was observed, with Mn release by either reductive or induced dissolution increasing linearly with decreasing pH. The fast kinetics of the DFOB-promoted dissolution of hausmannite, as compared to iron oxides, suggest that the siderophore-promoted dissolution of Mn(III)-bearing minerals may compete with the siderophore-promoted dissolution of Fe(III)-bearing minerals.     

The 825-1110 angstroms EUV spectrum of Venus

On 15 August 1994 we launched the EUVS sounding rocket payload to observe the 825-1110 angstrom region of Venus's far ultraviolet airglow spectrum. The EUVS telescope/spectrograph obtained good data at five times higher spectral resolution than was previously available in the far ultraviolet. We present these data and compare our results to those obtained by the Galileo UVS and Venera 11/12 UV spectrophotometers. We identify several new spectral emission features, including both singly ionized nitrogen and molecular nitrogen in Venus's spectrum. We also see evidence for electron-impact-induced emission from CO. Finally, the EUVS data indicate that the "Ar" emissions detected in Venus's far ultraviolet spectrum by Venera 11/12 spectrophotometers are in fact not due to argon, thus eliminating the discrepancy between in situ and remote sensing measurements.     

A pollution history of Chesapeake Bay

Present day anthropogenic fluxes of some heavy metals to central Chesapeake Bay appear to be intermediate to those of the southern California coastal region and those of Narragansett Bay. The natural fluxes, however, are in general higher. On the bases of Pb-210 and Pu-239 + 240 geochronologies and of the time changes in interstitial water compositions, there is a mixing of the upper 30 or so centimeters of the sediments in the mid-Chesapeake Bay area through bioturbation by burrowing mollusks and polychaetes. Coal, coke and charcoal levels reach one percent or more by dry weight in the deposits, primarily as a consequence of coal mining operations.     

On the sources of ultraviolet absorption in spectra of Titan and the outer planets

In response to the observations of the ultravioler deficiencies shown by all of the outer planets and Titan, models have been proposed to explain the low albedos by absorption by particles in the upper atmospheres of these objects. These particles are generally believed to be photochemically formed from gases in the upper atmospheres, primarily methane and hydrogen. Such processes may also be operative on Titan. The results of some laboratory experiments of the proton irradiation of mixtures of gases including CH₄ H₂, NH₃, etc., have shown that liquid and solid materials are produced that are strong ultraviolet absorbers. However, the material produced from the CH₄ + H₂ mixture was colorless, indicating that species containing elements other than carbon and hydrogen are necessary for the production of color. Two such elements are nitrogen (as NH₃ or N₂) and sulfur (as H₂S) and colored materials have been produced from such mixtures. None of these materials has spectral properties identical to those shown by the planets. Therefore it is necessary that mixtures (and/or cloud layers) of the photochemical materials be present.     

Significance of Landscape Age,Uplift, and Weathering Rates to Ecosystem Development

The combined roles of chemical and physical weathering have profound effects on the development of terrestrial ecosystems. Landscapes which are tectonically active are rapidly denudated and continually produce nutrient solutes from fresh bedrock. The chemical weathering yields are related to climate, but also to geologic factors such as uplift rates. Long-term nutrient production and the phase of ecological development are closely related to geological setting. Until recently, this relationship has not been seriously considered by ecologists. Our analysis of existing information suggests, however, not only that the nature and type of geologic processes provide significant insights into landscape, but also to ecological development. In this paper, we describe the impact of geologic uplift on the long term generation of soluble nutrients from bedrock by evaluating long-term data from a number of forested sites and comparing it to newly collected data from Taiwan, an area undergoing rapid tectonic uplift.     

An active source electromagnetic sounding system for marine use

Instrumentation has been developed for carrying out active source electromagnetic sounding experiments in the deep oceans. Experiments of this type are directly and uniquely sensitive to the presence of molten or partially molten material, to temperature structure and to the porosity of upper crustal rocks such as those that accommodate hydrothermal circulation systems. Electromagnetic sounding experiments therefore represent an extremely desirable addition to the existing range of geophysical techniques for studying geological processes in thermally, hydrothermally or magmatically active regions—for example, at oceanic spreading centres.The instruments can be operated in regions of rugged, unsedimented sea bottom terrain, and are designed for investigating the distribution of electrical conductivity within the oceanic crust and uppermost mantle. The instrumentation consists of a deep towed, horizontal electric dipole transmitter and a set of free-fall, sea bottom, horizontal electric field recording devices.The transmitter is a deep-towed instrument, which is provided with power from the towing ship through a conducting cable. The transmitter package is fitted with an integral echo sounder, which allows it to be towed safely a short distance above the seabed. Electromagnetic signals are transmitted from a neutrally-buoyant antenna array, which is streamed behind the deep tow.The sea bottom receiving instruments each consist of a recoverable package which contains the instrumentation and digital recording system, an acoustic release unit, four low-noise, porous electrodes arranged in two orthogonal, horizontal dipoles, and a disposable bottom weight.The instruments have been used at sea on three occasions. On their most recent use, active source signals were successfully recorded during an experiment to investigate crustal magmatism and hydrothermal circulation beneath the axis of the East Pacific Rise.     

Late Paleozoic gabbroic rocks of the Bridge River accretionary complex,southwestern British Columbia: geology and geochemistry

Gabbroic bodies in the Bralorne-Gold Bridge area of southwestern British Columbia are associated with the oceanic Bridge River complex of the western Canadian Cordillera, one of the suspect terranes accreted to North America in the Jurassic. The gabbros are locally cut by tonalites and are structurally interleaved with ultramafic rocks, phyllites, graphitic cherts, and carbonate lenses that comprise the lower part of the Bridge River complex. Their late Carboniferous crystallization age overlaps the depositional age of affiliated supracrustal rocks (Mississippian-Jurassic), some of which have been metamorphosed to blueschist facies. Compositionally, the gabbros resemble mafic plutonic rocks of ophiolitic complexes and gabbroic rocks of the nearby Shulaps Range. They display some affinity to oceanic island arc tholeiitic suites. The Bralorne and Shulaps gabbros include cumulates and appear to have been derived from a single, light REE-depleted, peridotitic source by melting and subsequent fractional crystallization/accumulation of various combinations of plagioclase, pyroxenes, and olivine. The tonalites are compositionally distinct from typical ophiolitic plagiogranites, but might be related to the associated gabbros. The gabbroic bodies occur within tectonic slivers derived from the oceanic crust that floored a deep ocean basin that existed during the late Paleozoic and early Mesozoic. The Bridge River complex comprises fragments of oceanic crust that were tectonically incorporated into an east-verging accretionary prism during a middle/late Triassic to Jurassic collisional event.     

Mineralogy and origin of rhizoliths on the margins of saline,alkaline Lake Bogoria,Kenya Rift Valley

A wide range of rhizoliths occurs around the margins of Lake Bogoria, Kenya. These include root casts, moulds, tubules, rhizocretions, and permineralised root systems. These rhizoliths are variably composed of opaline silica, calcite, zeolites (mainly analcime), fluorite, and possibly fluorapatite, either alone or in combinations. Some rhizoliths are infilled moulds with detrital silicate grains. Most rhizoliths are in situ, showing both vertical and horizontal orientations. Reworked rhizoliths have been concentrated locally to form dense rhizolites.Hot-spring fluids, concentrated by evapotranspiration and capillary evaporation, have provided most of the silica for the permineralisation of the plant tissues. Precipitation involved the growth of silica nanospheres and microspheres that coalesced into homogeneous masses. Calcite rhizoliths formed following evaporative concentration, evapotranspiration, and (or) CO₂ degassing of Ca-bearing runoff water that infiltrated the sediment, or by mixing of runoff with saline, alkaline groundwater. Fluorite precipitated in areas where mixing of hot-spring and meteoric waters occurred, or possibly where hot-spring fluids came into contact with pre-existing calcite. Zeolitic rhizoliths formed during a prolonged period of aridity, when capillary rise and evaporative pumping brought saline, alkaline waters into contact with detrital silicate minerals around roots.     

Geology of London,UK

The population of London is around 7 million. The infrastructure to support this makes London one of the most intensively investigated areas of upper crust. However construction work in London continues to reveal the presence of unexpected ground conditions. These have been discovered in isolation and often recorded with no further work to explain them. There is a scientific, industrial and commercial need to refine the geological framework for London and its surrounding area. This paper reviews the geological setting of London as it is understood at present, and outlines the issues that current research is attempting to resolve.