نتایج جستجو برای: lake sediment

تعداد نتایج: 75775  

2010
Jennifer A. Nelson Gabriel Filippelli

Records from lake sediment cores are critical for assessing the relative stability of climate and ecosystems over the Holocene. Duck Lake in south-central Lower Michigan, USA, was the focus of a study that identified how changes in the geochemical variables in lake sediments relate to variations in regional climate and local land use during the Holocene. More than 8.5 m of lacustrine sediment w...

2010
Suzanne A. G. Leroy Meriç Albay

Lake Sapanca, which is located on the Sakarya-Sapanca-İzmit corridor in NW Turkey, is a freshwater lake with numerous fish farms in its catchment. Palynological analyses including non-pollen palynomorphs of a short (38.5 cm) and a longer sediment core (586 cm), taken in the centre of the lake and dated in previous investigations, revealed the presence of brackish and marine palynomorphs. The lo...

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....

2007
Xiaobo Chao Yafei Jia F. Douglas Shields Charles M. Cooper

Sediment is a major nonpoint-source pollutant, and the exchange of materials between water and sediment is an important component of the lake eutrophication process. Suspended sediment increases water surface reflectivity and light attenuation in the water column. Nutrients can be absorbed to sediment particles and desorb from sediment to the water. In addition, nutrients can also be released f...

Journal: :Science 1984
R Y Anderson E B Nuhfer W E Dean

Volcanic ash from the eruption of Mount St. Helens on 18 May 1980 fell into Williams Lake in eastern Washington and was temporarily suspended at the sediment-water interface. After several months of compaction, the ash layer broke up and sank into lower density uncompacted lake sediment. Stratigraphic time displacements of several hundred years and a failure to recognize discontinuous ash layer...

2012
XUHUI DONG ENFENG LIU

The spatial distribution of surface sediment diatoms in Chaohu Lake (southeast China), and their relationships with environmental and spatial variables were analyzed in this study. The diatom assemblages were dominated by planktonic species. Three dominant species Cyclostephanos dubius, Aulacoseira granulata and Aulacoseira alpigena are unevenly distributed across the lake. The distribution of ...

2008
Robert G. Hatfield Barbara A. Maher

Accelerated erosion and transport of fine sediment from upland temperate catchments can reflect increased erosivity and/or erodibility, due in turn to climatic and/or human forcing. Identification of sediment fluxes and sources over Holocene timescales can both enable understanding of the relative impacts of these forcings, and provide perspective on recent sediment fluxes. Here we present a ~ ...

Journal: :Environmental toxicology and chemistry 2002
Heather A Morrison D Michael Whittle G Douglas Haffner

A food web bioaccumulation model was used to compare transport and fate of polychorinated biphenyls (PCB) congeners in three food webs in the Laurentian Great Lakes of North America. The model was used to quantify the contribution of sediment-derived and freely dissolved PCBs to the body burden of aquatic biota. In eastern Lake Erie (OH, USA), almost 100% of the chemical body burden of biota or...

2012
Byron A. Steinman Mark B. Abbott

Hydroclimate sensitivity simulations were conducted with a lake-catchment hydrologic and isotope mass balance model adapted to two small, closed lakes (Castor and Scanlon) located in the Pacific Northwest. Model simulations were designed to investigate the combined influences of persistent disequilibrium, reddening, and equifinality on lake water and sediment (i.e., biogenic and endogenic carbo...

2012
Aaron Richter

Introduction The City of Austin’s Watershed Protection Department strives to protect the water quality in Austin area watersheds. Austin creeks have been monitored for years through the Environmental The Austin Lake Index (ALI) was designed to provide a yearly assessment of the environmental integrity of Lake Austin, Lady Bird Lake, and Lake Long. Sub-indices used to compute the ALI include rep...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید