نتایج جستجو برای: lake sediment

تعداد نتایج: 75775  

ژورنال: کواترنری ایران 2018
Wigand, Petre Ernest,

During the Holocene Lake Orūmiye has been subjected to significant changes in climate. These have impacted the surround vegetation and runoff, and erosion rates of the surrounding basin. Shifts in seasonal rainfall from winter to summer dominated patterns have resulted in dramatic changes in the Orūmiye Basin’s vegetation cover from grass to shrub dominated communities. The degree of ground sur...

2017
K. R. Scheu D. A. Fong S. G. Monismith O. B. Fringer

Sediment dynamics were investigated in Lake Maggiore, Italy, with field observations from October to mid-December 2012. Three moorings were deployed in Pallanza Bay, a small embayment on the western side of the lake near the Toce River inflow, to measure temperature and currents throughout the water column and suspended sediment concentration (SSC) was estimated with acoustic instrumentation. R...

1995
Douglas R Hardy Raymond S Bradley Bernd Zolitschka

Annually-laminated clastic sediments preserve a high resolution proxy record of paleoclimate, provided that allochthonous sedimentation represents a response to meteorological forcing of watershed sediment transfer. Here, we demonstrate this linkage, and illustrate a calibration process using the most recent 40 years of a varve record from Lake C2 (82~ t N; 78000 ' W), three years of field meas...

2010
Steven M. Jepsen Edward E. Adams John C. Priscu

We examined sediment melt-migration dynamics in the ice cover of Lake Fryxell, Taylor Valley, McMurdo Dry Valleys, Antarctica, using a combination of laboratory experiments, field observations, and modeling. The specific objectives were to determine the thermal conditions required for sediment melt and how sediment migration rates vary with meteorological forcings and ice microstructure. These ...

Journal: Geopersia 2019

Maharlu Lake, located in the SW of Iran, has acted as a sink for various wastewater discharges in the last few decades. This study aimed at assessing potentially toxic elements (PTEs) distribution in sediment, surface and pore water samples of Maharlu Lake. To achieve that, the samples were collected from each compartment and the total concentration of PTEs (Al, Fe, Sc, Cr, Co, Ni, Zn, As, Sb, ...

Journal: :Journal of environmental quality 2005
B E Haggard P A Moore P B Delaune

Phosphorus inputs into reservoirs include external sources from the watershed and internal sources from the reservoir bottom sediments. This study quantified sediment P flux in Lake Eucha, northeastern Oklahoma, USA, and evaluated the effectiveness of chemical treatment to reduce sediment P flux. Six intact sediment-water columns were collected from three sites in Lake Eucha near the reservoir ...

2010
Nadia B.E. Badr Maged M.A. Hussein

Previous studies conducted on the hydrography, chemical and biological characteristics of Lake Edku; one of the northern Nile Delta Lakes, concluded that this lake suffered from a high level of eutrophication, due to the heavy load of nutrients, especially phosphorus. Before deciding what type of treatment should be used for decreasing total phosphorous (TP), knowledge of the sources and sinks ...

2004
Julie A. Wolin Eugene F. Stoermer

A paleolimnological investigation of post-European sediments in a Lake Michigan coastal lake was used to examine the response of Lower Herring Lake to anthropogenic impacts and its role as a processor of watershed inputs. We also compare the timing of this response with that of Lake Michigan to examine the role of marginal lakes as ‘early warning’ indicators of potential changes in the larger c...

2008
Donald T. Rodbell Geoffrey O. Seltzer Bryan G. Mark Jacqueline A. Smith Mark B. Abbott

We developed records of clastic sediment flux to 13 alpine lakes in Peru, Ecuador, and Bolivia, and compared these with independently dated records of regional glaciation. Our objectives are to determine whether a strong relationship exists between the extent of ice cover in the region and the rate of clastic sediment delivery to alpine lakes, and thus whether clastic sediment records serve as ...

2005
J. C. Rowland

Once cut off from the main stem of the river, oxbow lakes commonly remain connected to the active river through narrow self-formed channels which evolve at the time of lake formation. These channels, referred to here as “tie channels” (Blake and Ollier 1971), allow the regular exchange of water and sediment; flow enters the lake when river stage exceeds lake stage and drains from the lake as ri...

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