Variação sazonal da estrutura de massas de água na plataforma continental do Amazonas e área oceânica adjacente

Silva, Alex Costa da; Araujo, Moacyr; Bourlès, Bernard

doi:10.1590/s0102-261x2005000200004

Cited by 36 publications

(23 citation statements)

References 10 publications

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“…T is the temperature, S is the salinity and D is the conventional density. Da Silva et al, 2005;Miranda, 1982Miranda, , 1985. The water masses were defined according to the TS diagram that was generated from the correlations between temperature (T) and salinity (S) data.…”

Section: Ts Diagram Of the Continental Shelf And Jaguaribe Estuary Rementioning

confidence: 99%

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Dias

Castro

Lacerda

2013

Continental Shelf Research

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Section: Ts Diagram Of the Continental Shelf And Jaguaribe Estuary Rementioning

confidence: 99%

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Dias

Castro

Lacerda

2013

Continental Shelf Research

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“…2b). The 24.5 isopycnal, SACW lower density limit (Silva et al 2005), rose from 15 m to the surface at t = 36 h ( ) at the beginning of the study period (February 19) through the following 48 h carried the surface water out of the coast, allowing the deeper SACW to move up to the surface by the third sampling day (February 21) (Fig. 3).…”

Section: Hydrologymentioning

confidence: 99%

Plankton trophic structure and particulate organic carbon production during a coastal downwelling-upwelling cycle

Guenther¹,

Gonzalez‐Rodriguez²,

Carvalho³

et al. 2008

Mar. Ecol. Prog. Ser.

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) indicated the establishment of a herbivorous food web structure. Particulate organic carbon (POC) production was mainly due to phytoplankton (98%) and did not differ between periods. However, the observed variability in plankton trophic interactions should affect the magnitude of POC export from this dynamic system. KEY WORDS: Food webs · Carbon fluxes · Bacterioplankton · Phytoplankton · Zooplankton · Cabo Frio · South Brazil Bight Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 363: [109][110][111][112][113][114][115][116][117][118][119] 2008 small phytoplankton and bacteria to larger zooplankton and then higher pelagic trophic levels is mediated by heterotrophic nano-and micro-sized protists (Sherr et al. 1986). Therefore, in these microbial food webs, most of the biogenic carbon produced is recycled within the system through heterotrophic respiration (Legendre & Le Fevre 1995).In contrast, in more eutrophic systems with low vertical stability, larger phytoplankton cells are more representative and usually dominant, where turbulence simultaneously provides nutrient and prevents sinking below the euphotic zone (Kiørboe 1993). In those conditions an herbivorous food web prevails and most of the POC produced is exported via grazing, as the mesozooplankton are the dominant primary consumers (Legendre & Rassoulzadegan 1996). Moreover, carbon export is directly related to the input and uptake of 'new' nutrients, mainly nitrate (N-NO 3 ) to the euphotic zone (Dugdale & Goering 1967), and this nitrogen form is primarily utilized by larger cells, such as diatoms (Price et al. 1985).Coastal waters influenced by upwelling are among the most productive aquatic systems. The periodical wind-driven transport of surface waters offshore and the consequent upwelling of deeper water masses provide enrichment to previously oligotrophic waters. The high nutrient input to the surface waters, especially N-NO 3 , stimulates phytoplankton production, mainly for larger species, resulting in higher mesozooplankton and fisheries productivity. This pattern has been described for several upwelling zones around the world, such as those in the SE Pacific Ocean , Iriarte & Gonzalez 2004, Fernandez-Alamo & Farber-Lorda 2006, NE Pacific Ocean (Peterson et al. 1979, Collins et al. 2003, NE Atlantic Ocean (Bode et al. 2003), and Indian Ocean (Brown et al. 2002).Upwelling zones usually occur along eastern ocean boundaries, between 30°N and 30°S, due to the dominance of the trade winds. In the SW Atlantic, however, the change in the coastal direction at 23°S (Cabo Frio, SE Brazil) from N-S to E-W, along with the proximity of the 100 m isobath to the coast, allow the NE winds to move surface waters offshore and the consequent upwelling of the South Atlantic Central Water (SACW). This results in a high productivity core in the midst of the otherwise oligotrophic Brazilian Current waters (Valentin 1984a). The upwelling of deeper water masses is reversed when shifts in wind direction bring surface w...

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“…Neste sentido, Gibbs (1970), e mais recentemente Silva et al (2005a;2005b); Silva (2006), além de outros, têm demonstrado como situação extrema que a pluma d'água superficial com baixo valor de salinidade, resultante da descarga do rio Amazonas, pode atingir centenas de quilômetros da costa na porção oeste e leste do oceano Atlântico equatorial, no qual sofre deslocamento espacial e sazonal por processos advectivos (ventos e correntes). No caso da influência dos aportes continentais oriundos do Golfão Maranhense, esta pluma espalhou-se até uma distância de cerca de 85 km da costa no mês de Junho/1999,época que corresponde aos maioresíndices de precipitação na região (Fig.…”

Section: Discussionunclassified

“…O mais caudaloso deleś e o rio Amazonas, cuja descarga provoca a formação de uma extensa pluma deágua de baixa salinidade, atingindo centenas de quilômetros em direção mar aberto, mais de 1000 km em direção noroeste, e mesmo penetrando no Oceano Atlântico Norte (Gibbs, 1970;Hellweger & Gordon, 2002;Silva et al, 2005b;Ffield, 2007).…”

Section: Introductionunclassified

Caracterização hidrográfica da plataforma continental do maranhão a partir de dados oceanográficos medidos, remotos e modelados

Silva¹,

Araújo²,

Pinheiro³

2007

Rev. Bras. Geof.

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ABSTRACT. The objective of this work is to characterize the spacial variability of the thermohaline surface properties in the Maranhão continental shelf and adjacent oceanic area, during two different periods, associated to the distinct characteristics of atmospheric and continental forcings -November/1997 and June/1999. This paper presents the results of simultaneous shipboard measurements collected during oceanographic cruises of the program "REVIZEE/SCORE-NO". Numerical model outputs and satellite data complement the results of hydrographical observations. In the inner shelf (limited at isobath 50 m), the distributions of salinity and temperature are mainly affected by fresh water discharge (observed during June/1999). The distributions of SST in the adjacent oceanic region can be explained by the influence of the North Brazil Current (NBC). Model results and hydrographic observations indicate that the mixed layer depth in the oceanic region adjacent to the Maranhão continental shelf is influenced by seasonal variability of the NBC transport associated with the position and the intensification of the high salinity core of the NBC.

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Variação sazonal da estrutura de massas de água na plataforma continental do Amazonas e área oceânica adjacente

Cited by 36 publications

References 10 publications

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Continental shelf water masses off the Jaguaribe River (4S), northeastern Brazil

Plankton trophic structure and particulate organic carbon production during a coastal downwelling-upwelling cycle

Caracterização hidrográfica da plataforma continental do maranhão a partir de dados oceanográficos medidos, remotos e modelados

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