نتایج جستجو برای: geomorphic conditions
تعداد نتایج: 849963 فیلتر نتایج به سال:
The interaction of geomorphic and ecologic landscape components has been largely conceptualized as independent. In one direction, geomorphic processes and landforms shape the distribution of biota. Conversely, in the other direction, biota modify geomorphic processes and landforms. Increasingly, the interactions between geomorphic and ecological components are more circular and developmentally ...
Terrestrial paleoclimate records rely on proxies hosted in alluvial strata whose beds are deposited by unsteady and nonlinear geomorphic processes. It is broadly assumed that this renders the resultant time series of terrestrial paleoclimatic variability noisy and incomplete. We evaluate this assumption using a model of oscillating climate and the precise topographic evolution of an experimenta...
The last maximum glacier advance in many mountain ranges appears to have predated the last maximum advance of the Wisconsinan continental ice sheets (-20,000 years B.P.). Published evidence from widely spaced localities in North and South America, Europe, Asia, and Hawai'i suggests that some mountain glaciers extended farther during one or more stades early in the last glaciation, roughly 115,0...
Dams are known to impact river channels and ecosystems, both during their lifetime and in their decommissioning. In this study, we applied a before-after-control-impact design associated with two small dam removals to investigate abiotic and biotic recovery trajectories from both the elimination of the press disturbance associated with the presence of dams and the introduction of a pulse distur...
Aquatic ecosystems play an important role in the global carbon (C) cycle and represent substantial source of greenhouse gases to the atmosphere. However, little attention has been paid to quantifying how aquatic community respiration (CR), a major source of CO2, will respond to warming temperatures expected under climate change, and whether landscape features affect temperature modulation of CR...
Varnish microlamination (VML) dating is a correlative age determination technique that can be used to date and correlate various geomorphic features in deserts. In this study, we establish a generalized late Quaternary (i.e., 0–300 ka) varnish layering sequence for the drylands of western USA and tentatively correlate it with the SPECMAP oxygen isotope record. We then use this climatically corr...
In the summer of 2001, an intense thunderstorm in southeastern Caspian Sea triggered a catastrophic flood in the Madarsoo basin . Use of methods including high-resolution aerial photographs and satellite images interpretation, multi-date mapping, hydraulic calculations and field observations made possible the documentation of the geomorphic impacts on the Madarsoo River and its tributaries. Geo...
We examine how historic flooding in 2011 affected the geomorphic adjustments created by dam regulation along the approximately 120 km free flowing reach of the Upper Missouri River bounded upstream by the Garrison Dam (1953) and downstream by Lake Oahe Reservoir (1959) near the City of Bismarck, ND, USA. The largest flood since dam regulation occurred in 2011. Flood releases from the Garrison D...
—Hydrogeomorphic processes play key roles in creating, modifying, or destroying aquatic habitat and act as ecological disturbances that shape ecosystem characteristics and dynamics. Within the broad regional context set by general patterns of climate, physiography (geology and topography), and vegetation, the combined influences of the hydrologic, geomorphic, and vegetation regimes dominate the...
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