نتایج جستجو برای: river and lake
تعداد نتایج: 16861317 فیلتر نتایج به سال:
126 abstract: in this research we studied the effects of cyclic hydration and dehydration of cysts of artemia urmiana and artemia parthenogenetica on the hatching percentage, survival and growth. the experiment was carried out in 3 treatments (1-3 hydration/dehydration cycles) with 3 replicates for each treatment. later effects of cold preservation at -20°c during three time periods were ...
The Northern Rivers Ecosystem Initiative (NREI) was established in the late 1990s to address important science questions resulting from previous studies undertaken by the Northern Rivers Basin Study (NRBS). This manuscript summarizes the results from a number of reports on hydrologic research conducted on the Peace-Athabasca-Slave river and lake systems. Specific concerns expressed by the NRBS ...
Heavy metal (Cr, Ni, Cu, Zn, Cd, and Pb) pollution, fractionation, and ecological risks in the sediments of Lake Chaohu (Eastern China), its eleven inflowing rivers and its only outflowing river were studied. An improved BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure was applied to fractionate heavy metals within sediments, a geoaccumulation index w...
rivers and runoff have always been of interest to human beings. in order to make use of the proper water resources, human societies, industrial and agricultural centers, etc. have usually been established near rivers. as the time goes on, these societies developed, and therefore water resources were extracted more and more. consequently, conditions of water quality of the rivers experienced rap...
An assemblage of fossil sockeye salmon was discovered in Pleistocene lake sediments along the South Fork Skokomish River, Olympic Peninsula, Washington. The fossils were abundant near the head of a former glacial lake at 115 m elevation. Large adult salmon are concentrated in a sequence of death assemblages that include individuals with enlarged breeding teeth and worn caudal fins indicating mi...
Combined sewer overflows (CSOs) negatively affect water quality in urban river and lake systems worldwide by contributing thermally enhanced waters, particulates, and various organic and inorganic contaminants. Cities that utilize CSOs must reassess aging sewer systems or minimize the impact overflows have on water quality. The Buffalo River, which drains into northeastern Lake Erie, receives c...
A study by the Environmental Protection Agency will report that the St. Joseph River is contributing pollutants to Lake Michigan later this year, officials from the EPA said this week. The study Lake Michigan Mass Balance, founded in 1994. discovered two toxins that are particularly prevalent in the river. High levels of atrazine and trans-nonachlor compounds were found in the water. “St. Joe i...
Schizopygopsis stoliczkai (Cyprinidae, subfamily Schizothoracinae) is one of the major freshwater fishes endemic to the northwestern margin of the Tibetan Plateau. In the current study, we used mitochondrial DNA markers cytochrome b (Cyt b) and 16S rRNA (16S), as well as the nuclear marker, the second intron of the nuclear beta-actin gene (Act2), to uncover the phylogeography of S. stoliczkai. ...
This study describes the metabolic capacities of the African cichlid Pseudocrenilabrus multicolor victoriae from four sites in Uganda, East Africa. Fish were captured during the dry season, from two aquatic systems in different regions (Lake Nabugabo and Mpanga River). Within the Lake Nabugabo region, individuals were sampled from Lake Kayanja (normoxic) and Lwamunda Swamp (hypoxic); within the...
The Zebra mussel (Dreissena polymorpha), one of the most widely used bioindicators of persistent organic pollutants, trace metals and radionuclides in several worldwide freshwater ecosystems, has been used to monitor DDT contamination trends in Lake Maggiore since 1996, caused by industrial effluents on a tributary of the River Toce, one of the major affluents of the lake. Dreissena specimens w...
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