%0 Journal Article
%T Export of materials along a tidal river channel that links a coastal lagoon to the adjacent sea
%A Javier Aldeco Ram¨ªrez
%A Martha Signoret Poillon
%A Mar¨ªa Adela Monreal G¨®mez
%A David Alberto Salas de Le¨®n
%J Brazilian Journal of Oceanography
%D 2012
%I Universidade de S?o Paulo
%R 10.1590/s1679-87592012000300004
%X Intratidal variability and flux of salt, chlorophyll-a and suspended materials were evaluated in a shallow tropical tidal channel linking a coastal lagoon to the western Gulf of Mexico. Velocity, temperature and conductivity were used to calculate the fluxes. Data were recorded during three tidal velocity cycles (tvc) under extreme river discharge conditions. Chlorophyll-a and suspended materials were determined below the surface. In both seasons (dry and rainy), the flow was ebb-dominated and with longer duration than when in flood. Maximum current velocities were 0.30 m s-1 in May (dry season) and 0.60 m s-1 in September (rainy season). In the dry season the mean chlorophyll-a export was of 7.56 Kg over tvc while the import was of 3.32 Kg. In the rainy season mean export (47.3 Kg) was 6 times greater than the import (7.93 Kg over tvc). Phytoplankton was dominated by organisms of marine origin. The mean of exported, suspended materials in the rainy season (111.3 Kg) was 4.6 times greater (859 Kg) than that in the dry season (184.7 Kg over tvc). Tidal velocity asymmetry is an effective mechanism of exportation, introducing relatively warm and saltier water into the river through the tidal channel. A variabilidade intramar¨¦, o fluxo de salinidade, a clorofila-a e material em suspens o foram avaliados em um canal superficial de mar¨¦ tropical em uma lagoa costeira ao oeste do Golfo do M¨¦xico. Os dados de velocidade, temperatura e condutividade foram usados para c¨¢lculo dos fluxos durante tr¨ºs ciclos de velocidades das mar¨¦s (tvc) sob condi  es extremas de descarga. A Clorofila-a e material em suspens o foram determinados abaixo em subsuperf¨ªcie. Em ambas as esta  es (seca e chuvosa), o fluxo dominante foi durante o refluxo e com dura  o maior durante o fluxo de entrada. A m¨¢xima velocidade encontrada foi 0.30 m s-1 em maio (esta  o seca) e 0.60 m s-1 em setembro (esta  o chuvosa). Durante a ¨¦poca seca foram exportadas 7.56 Kg de clorofila-a, enquanto a importa  o foi de 3.32 Kg. Durante a temporada de chuva a m¨¦dia exportada (47.3 Kg) foi seis vezes maior que a importada (7.93 Kg). A concentra  o media de material em suspens o exportado durante a ¨¦poca de chuvas (111.3 Kg) foi 4.6 vezes maior (859 Kg) que durante esta  o de seca (184.7 Kg). A assimetria das mar¨¦s ¨¦ um mecanismo efetivo de transporte, introduzindo no rio ¨¢guas relativamente quentes e mais salinas atrav¨¦s do canal de mar¨¦.
%K Ambiente intermar¨¦s
%K Sais
%K Clorofila-a
%K Material em suspens o
%K Golfo do M¨¦xico
%K Tidal channel
%K Intertidal variability
%K Salt
%K Chlorophyll-a
%K Suspended materials
%K Gulf of M¨¦xico
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-87592012000300004