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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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5 recordsLinked to original sources
USGS2003

La mondialisation des poussieres, les vents transportent, d'un continent a l'autre, des poussieres, mai aussi des micro-organismes et des substances toxiques. Ces "passagers clandestins" pourraient transporter des maladies et modifier les ecosystems

Un tour d'horizon de la littérature scientifique révèle que de nombreux champs d'investigation sont jugés dignes d'intérêt de façon périodique : certaines idées sont à la mode pour un temps, puis sombrent dans l'oubli, avant de refaire surface comme si elles n'avaient jamais été émises. L'aérobiologie, c'est-à-dire l'étude des micro-organismes, tels des bactéries et des pollens transportés par les airs, est l'un de ces domaines.

Pour la Science↗
USGS2004

World heritage site - Bien du Patrimoine Mondial - Kluane/Wrangell-St. Elias/Glacier Bay/Tatshenshini-Alsek

The four parks depicted on this map make up a single World Heritage Site that covers 24.3 million acres. Together, they comprise the largest internationally protected land-based ecosystem on the planet. The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the World Heritage Program in 1972 for the identification and protection of the world?s irreplaceable natural and cultural resources. World Heritage Sites are important as storehouses of memory and evolution, as anchors for sustainable tourism and community, and as laboratories for the study and understanding of the earth and culture. This World Heritage Site protects the prominent mountain ranges of Kluane, Wrangell, Saint Elias, and Chugach. It includes many of the tallest peaks on the continent, the world's largest non-polar icefield, extensive glaciers, vital watersheds, and expanses of dramatic wilderness. [Les quatre parcs figurant sur cette carte ne constituent qu?un seul site du patrimoine mondial recouvrant plus de 99 millions de km2, ce qui en fait le plus grand ecosysteme terrestre protege par loi internationale. En 1972, L?UNESCO (l?organisation des Nations Unies pour les sciences, l'education et la culture) a etabli le programme du patrimoine mondial afin d?identifier et de proteger les ressources naturelles et culturelles irremplacables de notre plan?te. Si les sites du patrimoine mondial sont si importants c'est parce qu'ils representent a la fois des livres ouverts sur l?histoire de la Terre, le point de depart du tourisme durable et du developpement des collectivites, des laboratoires pour etudier et comprendre la nature et la culture. Ce site du patrimoine mondial assure la protection des chaines de montagnes de Kluane, Wrangell, Saint Elias, et Chugach. On y trouve plusieurs des plus hauts sommets du continent, le plus grand champ de glace non-polaire du monde, d?immenses glaciers, des bassins hydrologiques essentiels, et de la nature sauvage a perte de vue. ]

Scientific Investigations Map↗
USGS2021

Maximizing the science and resource mapping potential of Orbital VSWIR Spectral measurements of Mars

The last 16 years witnessed a rapid growth in understanding the composition and aqueous alteration of Mars’ surface from orbital data from the Observatoire pour la Mineralogie, l’Eau, les Glaces et l’Activité (OMEGA) [1] and Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) [2]. Both are sensitive to water-, hydroxyl-, sulfate-, and carbonate-bearing and ferric phases that record past liquid water. As the spatial resolution of such data has improved, and supporting laboratory data have been acquired, the diversity of mineral phases that are recognized has likewise expanded. The same phases typically contain recoverable water, a resource for future human exploration, and are the only near-surface water reservoir in the >50% of Mars over which ice likely does not occur in the shallowest subsurface. Knowledge of the distribution and abundance of these water-bearing phases, and their geologic implications, is limited by spatial resolution of the available data. A revolutionary advance in understanding the inventory, diversity, and stratigraphy of these materials can be obtained from Mars orbit, using two complementary approaches: hyperspectral imaging at ~6 meters per pixel at 0.7–4 µm, and 1 meter-per-pixel imaging at selected VSWIR wavelengths from 0.4–1.7 µm.

Bulletin of the AAS↗
USGS2014

Mechanisms driving recruitment variability in fish: comparisons between the Laurentian Great Lakes and marine systems

In his seminal work, Hjort (in Fluctuations in the great fisheries of Northern Europe. Conseil Parmanent International Pour L'Exploration De La Mar. Rapports et Proces-Verbaux, 20: 1–228, 1914) observed that fish population levels fluctuated widely, year-class strength was set early in life, and egg production by adults could not alone explain variability in year-class strength. These observations laid the foundation for hypotheses on mechanisms driving recruitment variability in marine systems. More recently, researchers have sought to explain year-class strength of important fish in the Laurentian Great Lakes and some of the hypotheses developed for marine fisheries have been transferred to Great Lakes fish. We conducted a literature review to determine the applicability of marine recruitment hypotheses to Great Lakes fish. We found that temperature, interspecific interactions, and spawner effects (abundance, age, and condition of adults) were the most important factors in explaining recruitment variability in Great Lakes fish, whereas relatively fewer studies identified bottom-up trophodynamic factors or hydrodynamic factors as important. Next, we compared recruitment between Great Lakes and Baltic Sea fish populations and found no statistical difference in factors driving recruitment between the two systems, indicating that recruitment hypotheses may often be transferable between Great Lakes and marine systems. Many recruitment hypotheses developed for marine fish have yet to be applied to Great Lakes fish. We suggest that future research on recruitment in the Great Lakes should focus on forecasting the effects of climate change and invasive species. Further, because the Great Lakes are smaller and more enclosed than marine systems, and have abundant fishery-independent data, they are excellent candidates for future hypothesis testing on recruitment in fish.

Laurentian Great Lakes↗