Water mass characteristics and geostrophic circulation in the South Brazil Bight: Summer of 1991

Abstract

A hydrographic survey on board the German ship FS Victor Hensen was carried out in Brazilian coastal waters between Santos (23°56'S) and Rio de Janeiro (22°54'S) from January 15 to January 22, 1991. Analyses of conductivity‐temperature‐depth (CTD) data collected during this cruise show that the geostrophic flow and water mass structure of the Brazil Current in that region have characteristics similar overall to those in the better observed Cabo Frio region. The uppermost 200 m of the water column is dominated by the warm, highly saline Tropical Water flowing predominantly to the southwest. This flow direction appears to persist to approximately 900 m, the maximum depth reached by the CTD casts. The water lying between 250 and 750 m has the characteristics of South Atlantic Central Water (SACW). Below 750 m, down to 900 m, the water characteristics are those of Antarctic Intermediate Water. The thermohaline structure and geostrophic calculations indicate the presence of a meandering pattern, with a trough that appears to be the early stage of formation of a cold‐core eddy over the upper slope region. This feature extends from the surface down to approximately 500 m depth and is apparently associated with the intrusion of SACW onto the continental shelf. The geostrophic computations (with respect to two reference levels, 750 and 900 dbar) yield maximum current values in the range 0.6–0.7 m s−1. The southwestward volume transport, averaged over the entire domain, was approximately 7.3 Sv with respect to 750 dbar and 8.8 Sv with respect to 900 dbar.

Variação temporal do zooplâncton da Praia de Tramandaí, Rio Grande do Sul, com ênfase em Copepoda

“…As variações na composição do zooplâncton observadas ao longo do estudo, reforçam que esta é uma região que recebe contribuições de água de diferentes origens, como a água tropical, de característica mais oligotrófica, transportada em direção sul pela Corrente do Brasil (CAMPOS et al, 1995), subantártica, subtropical e central do Atlântico Sul, transportadas para norte pela Corrente das Malvinas (CM) (PIOLA et al, 1999;CAMPOS et al, 2000) e o aporte de água doce proveniente do deságüe do rio Tramandaí. Assim como em outros estudos sobre o zooplâncton marinho (BJÖRNBERG, 1981;BRADFORD-GRIEVE et al, 1999;CAVALCANTI & LARRAZABÁL, 2004), o grupo Copepoda foi responsável pela maior diversidade, representado principalmente por espécies da Ordem Calanoida.…”

Subtropical Shelf Front off eastern South America

“…The surface T-S characteristics reveal that the cold anomalies match the South Atlantic Central Water (SACW) characteristics. SACW frequently occupies the near-bottom region of the outer continental shelf [Castro et al, 1987;Campos et al, 1995;Castro and Miranda, 1998] and is upwelled to the near surface in summer in the region off Cabo Frio [Bakum and Parrish, 1990;Matsuura, 1996].…”

“…Intense coastal upwelling is frequently observed in the region around Cabo Frio (22øS), and Ilha de S•o Sebasti•o (24øS). Wind-driven and shelf break upwelling induced by BC cyclonic meanders are believed to be responsible for pumping up nutrient-rich South Atlantic Central Water to the euphotic zone in the inner shelf [Campos et al, 1995, Matsuura, 1996.…”

Distribution related to temperature and salinity of the shrimps Acetes americanus and Peisos petrunkevitchi (Crustacea: Sergestoidea) in the south-eastern Brazilian littoral zone

“…On the shelf of Ubatuba, South Atlantic Central Water (SACW: T , 208C and S , 36) enters the region during the summer and spring months, and a strong thermocline is established during the period (Campos et al, 1995;Castro-Filho & Miranda, 1998). The opposite occurs during the winter months, when the Tropical Water mass (TW: T .…”