نتایج جستجو برای: rivers

تعداد نتایج: 19001  

2017
Sarah L. Engelhard Chantal M. Huijbers Ben Stewart-Koster Andrew D. Olds Thomas A. Schlacher Rod M. Connolly

using network analysis Sarah L. Engelhard*, Chantal M. Huijbers, Ben Stewart-Koster, Andrew D. Olds, Thomas A. Schlacher and Rod M. Connolly Australian Rivers Institute – Coast & Estuaries, and School of Environment, Griffith University, Gold Coast, Qld, Australia; School of Science and Engineering, University of the Sunshine Coast, Maroochydore DC, Qld, Australia; and Australian Rivers Institu...

Journal: :Bulletin of environmental contamination and toxicology 1994
Y Miyabara J Suzuki S Suzuki

Urban rivers are polluted with discharge from sewage treatment plants and overflowing sewage caused by rainfall (Nix and Merry, 1990; Shiraris et al., 1987). These waste waters accelerate eutrophication of aquatic environments. Since urban river water is the public water supply source, it is an i~0ortant for public health issue to determine whether or not urban rivers are polluted with fecal ef...

2006
M. Voss

Nitrate input to a river is largely controlled by land use in its catchment. We compared the information carried by the isotopic signatures of nitrate in 12 Baltic rivers, in relation to the vegetation cover, land use, and fertilization of agricultural land of their catchments. We found isotope values in nitrate ranging from −2 to 14‰ for δ15N and 8 to 25‰ for δ18O. The annual variability of ri...

2015
Chong Jiang Linbo Zhang Daiqing Li Fen Li Yingkui Li

In this research, monthly hydrological and daily meteorological data were collected across China for the period 1956–2012. Modified Mann–Kendall tests, double mass curve analysis, and correlation statistics were performed to identify the long-term trends and interrelation of the hydrometeorological variables and to examine the influencing factors of streamflow and sediment. The results are as f...

2014
Joseph E. Flotemersch Sheila North Karen A. Blocksom

Benthic macroinvertebrates are sampled in streams and rivers as one of the assessment elements of the US Environmental Protection Agency's National Rivers and Streams Assessment. In a 2006 report, the recommendation was made that different yet comparable methods be evaluated for different types of streams (e.g., low gradient vs. high gradient). Consequently, a research element was added to the ...

Journal: :international journal of health policy and management 2013
clive adams

there has been too much of a one-way flow drift down a river of evidence. researchers from rich countries have produced the primary evidence which they proceed to summarise within reviews. these summaries have directed care worldwide. however, things are changing and the river of evidence can flow in the other direction. the care of women with eclampsia has been changed or refined throughout th...

Journal: :Environmental Health Perspectives 1994
I I Wirgin C Grunwald S Courtenay G L Kreamer W L Reichert J E Stein

We determined levels of hepatic cytochrome P4501A (CYP1A) mRNA, hepatic DNA adducts, and fluorescent aromatic compounds (FACs) in bile, a measure of exposure to polyaromatic hydrocarbons, in Atlantic tomcod from six river systems ranging from highly polluted to relatively pristine on the northeast North American coast (the Hudson River, New York; the St. Lawrence River, Quebec; the Miramichi Ri...

Journal: :The Science of the total environment 2017
Helen P Jarvie Stephen M King Colin Neal

River water-quality studies rarely measure dissolved inorganic carbon (DIC) routinely, and there is a gap in our knowledge of the contributions of DIC to aquatic carbon fluxes and cycling processes. Here, we present the THINCARB model (THermodynamic modelling of INorganic CARBon), which uses widely-measured determinands (pH, alkalinity and temperature) to calculate DIC concentrations, speciatio...

Journal: :Conservation biology : the journal of the Society for Conservation Biology 2012
Sarah J Kupferberg Wendy J Palen Amy J Lind Steve Bobzien Alessandro Catenazzi Joe Drennan Mary E Power

Widespread alteration of natural hydrologic patterns by large dams combined with peak demands for power and water delivery during summer months have resulted in frequent aseasonal flow pulses in rivers of western North America. Native species in these ecosystems have evolved with predictable annual flood-drought cycles; thus, their likelihood of persistence may decrease in response to disruptio...

Journal: :The Science of the total environment 2016
V Montecino X Molina M Bothwell P Muñoz M L Carrevedo F Salinas S Kumar M L Castillo G Bizama R O Bustamante

We document the distribution of Didymosphenia geminata in central-southern Chilean rivers and identify the chemical and physical factors associated with its presence/absence (p/a). Repeated surveys in five successive years provided evidence that D. geminata could be nearing a biogeographic equilibrium in the region. D. geminata databases from extensive biological and environmental surveys in 18...

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