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| Bulgakov, Sn; Kushnir, Vm; Martinez, A. |
| A statistical evaluation of vertical current velocity profiles w(z) has been undertaken using data provided by current meter profilers. The calculation of profiles w(z) involves the estimation of the standard deviation of vertical current at each depth level, and the standard deviation of the statistical variability of that estimate. Profiles w(z) have been computed for the northwestern Black Sea, using current meter and CTD data from three surveys carried out during 1992-1994. The calculations show w(z) to have a two-layered structure, with zero values occurring in the main pycnocline. Such vertical current structures are consistent with a hydrodynamic model, whereby the current field is induced by buoyancy fluxes through the lateral basin boundaries.... |
| Tipo: Text |
Palavras-chave: Mer Noire; Circulation verticale; Chimie marine; Optique marine; Black Sea; Vertical circulation; Hydrochemistry; Hydrooptics. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00325/43602/43921.pdf |
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| LACERDA,LUIZ D.; SANTOS,JANAÍNA A.; MARINS,ROZANE V.; SILVA,FRANCISCO A.T.F. DA. |
| Abstract This work reviews the limnology of the largest multi-use reservoir in NE Brazil, the Castanhão Reservoir in Ceará State, during 5 years of an extended drought when the reservoir’s volume decreased from 88% to about 30%. Major physical and chemical parameters of the water column, phytoplankton community, trophic state and sediment geochemistry were monitored, as well as the impact from extensive aquaculture. Water quality of the full reservoir was maintained due to hydrodynamics, which transport nutrients to the hypolimnion of a stratified water column, rendering an oligotrophic state to the reservoir, notwithstanding the large nutrient inputs from aquaculture and irrigated agriculture. However, with the extension of the drought period, the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hydrochemistry; Hydrodynamics; Nutrients; Water quality; Sediments; Aquaculture. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000502073 |
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| Silva,Daniela M.L.; Camargo,Plínio B.; Mcdowell,William H.; Vieira,Ivan; Salomão,Marcos S.M.B.; Martinelli,Luiz A.. |
| Streamwater is affected by several processes in the watershed including anthropogenic activities that result in changes in water quality as well as in the functioning of these stream ecosystems. Therefore, this work aims to evaluate the concentration of major ions (Ca2+, Mg2+, Na+, K+, NH4+, NO3-, NO2-, Cl-, SO4(2-), PO4(3-), HCO3-) in streams in the state of São Paulo (southeast Brazil). The sampling sites are located at undisturbed (ombrophilus dense forest, semideciduous forest and savanna - cerrado) and disturbed areas (pasture, urbanization and sugar cane crops). Streamwater chemistry varied according to land use change and, in general, was higher in disturbed sites. Streams located in undisturbed sites at Ribeira de Iguape/Alto Paranapanema watershed... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hydrochemistry; Land use; Streams; Watersheds. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652012000400007 |
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