نتایج جستجو برای: urmia lake sediments

تعداد نتایج: 69393  

2017
Longfeng Wang Jun Xia Jingjie Yu Liyuan Yang Chesheng Zhan Yunfeng Qiao Hongwei Lu

Nansi Lake has been seriously affected by intensive anthropogenic activities in recent years. In this study, an extensive survey on spatial variation, pollution assessment as well as the possible sources identification of major nutrients (Total phosphorus: TP, Total nitrogen: TN, and Total organic carbon: TOC) in the surface sediments of Nansi Lake was conducted. Results showed that the mean co...

2015
Andrea K. Weber James M. Russell Timothy A. Goudge Mark R. Salvatore John F. Mustard Satria Bijaksana

We tested the use of visible to near-infrared (VNIR) reflectance spectroscopy to characterize the relative abundances of clay minerals in sediments from Lake Towuti, a large tectonic lake in Sulawesi, Indonesia. We measured VNIR spectra of lake and river sediments from Lake Towuti and its catchment to identify clay minerals, fit major VNIR absorption features with a modified Gaussian model to e...

The water crisis is one of the important issues in the Middle East countries. Many lakes are ‎drying up and/or facing critical situations, exerting tremendous impacts on the socio-economics ‎of their region. Lake Urmia, in northwestern Iran, currently is facing critical situations and is on ‎the brink of total ‎shrinkage and environmental disaster. This paper investigates the roots of crises ‎t...

Journal: :Journal of environmental quality 2004
Alan Steinman Rick Rediske K Ramesh Reddy

The release of P from lake sediments, which occurs as a part of internal loading, may contribute a significant portion of the total P load to a lake. Phosphorus release rates from sediments in Spring Lake, Michigan, and the degree to which alum reduces P release from these sediments, were investigated during the summer of 2003. Triplicate sediment cores were sampled from four sites in the lake,...

ژورنال: کواترنری ایران 2019
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Introduction Urmia Lake is one of the word-scale large hypersaline lakes with about 5500 square kilometers in the Turkish-Iranian Plateau (NW Iran). The lake surrounded by mountains with a mean elevation of about 2000 meters and the highest peak of 4811 meters. The lake charge with 28 permanent and ephemeral rivers. As a result of anthropogenic and natural reasons, the lake exposed to the rapi...

2006
Fasong Yuan Stephen S. Howe

Walker Lake, a hydrologically closed, saline, alkaline lake located along the western margin of the Great Basin of western United States, has experienced a 77% reduction in volume and commitment drop in lake level as a result of anthropogenic perturbations and climatic fluctuations over the last century. The history of lake-level change in Walker Lake has been recorded instrumentally since 1860...

2006

Bachmann et al. (2005) contend that a major fraction of flocculent sediments, a ‘‘fluid mud layer,’’ which has accumulated in Lake Apopka, Florida, since 1947, originated from sediment liquefaction of consolidated macrophyte-derived sediments. In addition, they contend that the underlying historic sediments are not only a major source of fluid mud, but also the source of organic matter for inte...

Journal: :Environmental science & technology 2005
Wenlu Song An Li Justin C Ford Neil C Sturchio Karl J Rockne Dave R Buckley William J Mills

Sediment cores were taken in 2002 in Lakes Michigan and Huron at six locations. A total of 75 samples were characterized, dated using 210Pb, and analyzed for 10 congeners of polybromodiphenyl ether (PBDE) including BDE209, as well as 39 congeners of polychlorinated biphenyls (PCBs). The concentrations of nine tri- through hepta-BDE congeners (Sigma9PBDE) in the surficial sediments range from 1....

2013
I. Gilmour

Lacustrine sediments from the 24 km diameter Boltysh impact structure record the rapid formation of an intra-crater lake. Stable isotope compositions and organic maturity parameters from the lake sediments deposited post-impact show that they were heated by underlying impactites. This heating is attributed to the establishment of an impactgenerated hydrothermal system. Estimates of the duration...

Journal: :Journal of environmental quality 2009
Marco A Belmont John R White K Ramesh Reddy

Phosphorus (P) can be an important nutrient in regulating primary productivity in lakes. The ability of lake sediments to retain P from external sources depends on the physiochemical characteristics of the sediment. To assess the P dynamics in Lake Istokpoga and the upper chain of lakes that drain into Lake Okeechobee, Florida, USA, sorption properties of batch sediment samples for Lakes Tohope...

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