Elements Covers

Thematic Articles

The Climate Component of Terroir

The choice of a given winegrape variety planted in its ideal climate, together with favorable topography and physical soil characteristics, combine to create the potential to produce fine wine. The French term terroir embodies this potential as a holistic concept that relates to both environmental and cultural factors that together influence the grape growing to wine production continuum. While the landscape, geology, and soil strongly interact to influence a vine’s balance of nutrients and water, it is the climate that is critical because it is this that limits where winegrapes can be grown at both the global and local scale. Whereas winegrape varieties are grown in numerous climates worldwide, they ultimately have relatively narrow climate zones for optimum growth, productivity and quality. In many regions a changing climate has already altered some aspects of winegrape production with earlier and more rapid plant growth and changes to ripening profiles and wine styles. As such the connections between varieties and their ideal terroirs are bound to be altered even further in the future. Research on grapevine and rootstock genetics, alterations in vineyard management, and adjustments in winemaking are addressing these issues to hopefully reduce the wine industry’s vulnerability and increase its adaptive capacity to future changes in climate.

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Major Soil-Related Factors in Terroir Expression and Vineyard Siting

A “terroir” is a cultivated ecosystem in which the vine interacts with the soil and the climate. The soil influences vine phenology and grape ripening through soil temperature, water supply and mineral supply. Limited water supply to the vines is critical for reaching a suitable grape composition in order to produce high quality red wines. Soil nitrogen availability also plays a key role in terroir expression. Ideally, vineyards should be established in areas where soil temperature (relative to air temperature), soil water-holding capacity (relative to rainfall and potential evapotranspiration) and soil nitrogen availability are optimum for the type of wine to be produced. Terroir expression can also be optimized by choosing appropriate plant material and via vineyard floor management techniques.

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The Formation of the Solar Systems: A Recipe for Worlds

This paper summarises the recipe – the raw and processed ingredients plus some of the processes – behind making our solar system 4,600 million years ago. Like a gourmand recipe, the solar system formed from many disparate ingredients, many of these ingredients themselves being the products of complex processes. Thus, to create the habitable solar system we see today required extensive work and processing. However, unlike a food recipe, much of how this happened is poorly understood, although a combination of new observations and analysis is ensuring that progress continues to be made.

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Comets in the Path of Earth

Earth’s atmosphere offers little protection against comet impacts, because many comets are bigger than 1 km. Fewer comets hit Earth than asteroids of the same size, except perhaps for sizes larger than 10 km. Comets release copious amounts of solid debris called meteoroids, and these meteoroids disperse to form meteoroid streams, some of which cause meteor showers on Earth. Recent meteor shower observations reveal the presence of potentially dangerous parent comets and trace their dynamical evolution. In addition, some showers leave a signature of “cosmic dust” in our atmosphere.

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Organic Molecules and Volatiles in Comets

Organic molecules and volatiles (e.g. H2O, CO, CO2) are the major components of comets. The majority of the organic compounds found within comets were produced by ice irradiation in dense molecular clouds and in the protoplanetary disk prior to comet formation. Comets are essentially repositories of protocometary material. As a result, comets do not show the clear trends in chemical and isotopic compositions that would be expected from our understanding of their formation locations. Rather, comets record chemical evolution in the protoplanetary disk and allow us to unveil the formation history of the organics and volatiles.

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The Rosetta Mission and the Chemistry of Organic Species in Comet 67P/Churyumov-Gerasimenko

Comets are regarded as probably the most primitive of solar system objects, preserving a record of the materials from which the solar system aggregated. Key amongst their components are organic compounds – molecules that may trace their heritage to the interstellar medium from which the protosolar nebula eventually emerged. The most recent cometary space mission, Rosetta, carried instruments designed to characterize, in unprecedented detail, the organic species in comet 67P/Churyumov–Gerasimenko (67P). Rosetta was the first mission to match orbits with a comet and follow its evolution over time, and also the first mission to land scientific instruments on a comet surface. Results from the mission revealed a greater variety of molecules than previously identified and indicated that 67P contained both primitive and processed organic entities.

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Flyby Missions to Comets and Return Sample Analysis

Images from flyby missions show comets to be geomorphically diverse bodies that spew jets of gas, dust, and rocks into space. Comet surfaces differ from other small bodies because of their ejection of mass into space. Comet solids >2 µm are similar to primitive meteorite ingredients and include the highest temperature materials made in the early solar system. The presence of these materials in ice-rich comets is strong evidence for large-scale migration of solid grains in the early solar system. Cometary silicates appear to have formed in numerous hot solar system regions. Preserved interstellar grains are rare, unless they have eluded identification by having solar isotopic compositions

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Seeing Snails in a New Light

Luminescence is exhibited by many common minerals, some of which have been exploited for dating. Calcite has the potential to date events that occurred over millions of years, but a series of challenges has hindered its use in dating limestone building stones, speleothems, and mollusk shells. Now, however, promising results from calcite luminescence dating have been achieved from an unexpected source: the opercula grown by certain species of snail. Coupled with innovations in luminescence imaging systems, snail opercula offer an exciting new approach that may finally unlock calcite’s potential for dating.

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Luminescence Thermochronometry: Investigating the Link between Mountain Erosion, Tectonics and Climate

Luminescence thermochronometry is a recently developed method that can constrain erosion histories at sub-Quaternary timescales. Luminescence thermochronometry determines the timing and rate at which electrons are trapped and thermally released in minerals, in response to in situ radiation and rock cooling. Erosion histories can be inferred by translating rock cooling rates into an erosion rate using knowledge of the Earth’s thermal field. In this article, we use examples of luminescence thermochronometry applied to the Himalaya mountains, the New Zealand Alps and the Japanese Alps to infer (and link together) wider aspects of regional erosion, climate and tectonic activity.

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