This article shows, by the application of quantitative ("Simpson Diversity Index" and "Habitat Weighting Method" estimating the diversity of past ecosystems and the landscape evolution) and qualitative methods ("Mutual Climatic Range Method or MCR" -- estimating past temperatures and precipitations) on the small mammal assemblages, new data about the human influence on small mammal species This influence is reflected in the Iberian archaeological sites since the Neolithic period with the establishment of the agriculture. However, in previous periods (late Pleistocene and early Holocene) environmental and climatic factors, such as the vegetation coverage or the temperatures, were the determinant causes in the specific composition of the small mammal species.
A microbial driver of chemical weathering in glaciated systems
Scott N. Montross et al., Department of Geography, Queen's University, Kingston, Ontario K7L 3N6, Canada. Posted online 13 Dec. 2012; http://dx.doi.org/10.1130/G33572.1.
Glaciological processes under ice sheets provide sustainable ecosystems for microbes, forming an aquatic environment through basal melting, and providing nutrients and energy from bedrock. Microbes facilitate solute production in most Earth-surface environments, but the balance of biotic and abiotic weathering in subglacial environment is presently unknown. This study by Scott N. Montross and colleagues demonstrates an up to eightfold increase in dissolved major cations in biotic relative to abiotic weathering experiments using glacial sediments and meltwater. This conclusion greatly expands our view of Earth's biogeochemically active weathering zone by incorporating the large wet-based portions of glaciated continents, both at present and during Earth's history. The profound environmental significance is that microbial processes h
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Geological Society of America