Oceanographic characteristics of Baía de Todos os Santos, Brazil

Abstract

ABSTRACT. Based on a vast set of in situ data, a first comprehensive overview of the oceanographic characteristics of Baía de Todos os Santos (BTS) is provided.BTS is the second largest coastal bay in Brazil (maximum area of 1223 km 2 and average depth of 9.8 m), and is located in the northeast Brazil, in the vicinity of Salvador city. The circulation inside the bay is mostly tidally driven and does not vary significantly throughout the year. On the other hand, the wet (winter) and dry (summer) seasons does alter significantly the distribution of water properties inside the BTS. During summer, the waters inside the bay have oceanic characteristics, with Tropical Water (TW) penetrating along the whole region, except for the mouth of Rio Paraguaçu. The water temperature inside the bay is higher than in the coastal zone, and variations can be up to 3 • C, reaching a maximum of nearly 30 • C. During winter, with the increase of freshwater inflow, salinity variations of about 4 are observed between the innermost stations inside BTS and the adjacent coastal region. Salinity values inside the bay can be as low as 32.3, inhibiting the penetration of TW into the BTS, which is totally occupied by a locally formed Coastal Water (CW). An evaluation of the flushing time is also provided and shows that during summer, a 60-fold increase can be observed compared to winter (38 days). While the circulation does not vary seasonally inside the bay, the associated inner shelf is characterized by two different scenarios. During summer, the upwelling favorable easterlies drive a southwestward flow, while during winter the more frequent occurrence of cold fronts (southerly winds) tend to reverse the circulation.Keywords: Baía de Todos os Santos, circulation, tides, water masses. RESUMO.Com base em um amplo conjunto de dados in situ, este artigo apresenta uma primeira caracterização oceanográfica da Baía de Todos os Santos. A BTSé a segunda maior baía costeira do Brasil (área máxima de 1223 km 2 e profundidade média de 9,8 m), e está localizada na região nordeste do Brasil, nas proximidades da cidade de Salvador. A circulação no interior da baíaé predominantemente forçada pelas marés e não varia significantemente ao longo do ano. Por outro lado, as estações chuvosa (inverno) e seca (verão) geram uma alteração significativa nas propriedades daságuas no interior da BTS. Durante o verão, aságuas dentro da baía têm características oceânicas, com aÁgua Tropical (AT) penetrando ao longo de toda a região, com exceção da desembocadura do Rio Paraguaçu. A temperatura dá agua dentro da baíaé maior do que a da região costeira adjacente, e estas variações podem ser de até 3 • C, atingindo um máximo de 30 • C. Durante o inverno, com o aumento do aporte deágua doce, variações de salinidade de cerca de 4 podem ser observadas entre a parte mais interna da BTS e a região costeira adjacente. Valores de salinidade dentro da baía podem chegar até 32,3, inibindo a penetração da AT dentro da BTS, que fica totalmente ocupada por umaágua costeira formada local...

Community structure of shallow rocky shore fish in a tropical bay of the southwestern Atlantic

“…This area harbors a high level of biodiversity, comprising distinct habitats such as coral reefs, mangrove swamps and seagrass beds (CASTRO;PIRES, 2001;LEÃO et al, 2003;REIS-FILHO et al, 2010;REIS-FILHO et al, 2011). The bay has a stable annual water temperature, with low temperature fluctuation varying generally between 23º and 27º C (CIRANO; LESSA, 2007).…”

Polyphysaceae (Dasycladales, Chlorophyta) in Todos os Santos Bay, Bahia, Brazil

“…1, Todos os Santos Bay is located in the state of Bahia, in northeastern Brazil (13°S; 38°W), and is the second largest bay in the country, covering an area of 1,233 km 2 , with 184 km of coastline (Cirano & Lessa 2007). The region around Todos os Santos Bay includes an urban area with more than 3 million residents, including the city of Salvador, and an extensive industrial zone with the largest petrochemical complex in the Southern Hemisphere (Camaçari Petrochemical Complex).…”

“…Todos os Santos Bay has essentially marine characteristics, given that the outflows of the Paraguaçu, Subaé and Jaguaripe rivers are far surpassed by the amount of salt water that enters the bay (Cirano & Lessa 2007). The water column is characteristically well-mixed, and estuarine conditions, which are found only near the mouths of the rivers, show high levels of biodiversity, making them of great ecological and extractive interest.…”

Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae) no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil

“…Segundo GiL & thomé (2004a), a baixa temperatura da água (15°C a 18°C) parece exercer influência no processo inicial de maturação. Estudos realizados em anos e pontos diferentes da BTS (cirano & Lessa, 2007;oLiveirasiLva et al, 2008;miLazzo et al, 2011), demonstraram que a temperatura da água varia entre 25° e 32,7°C, sendo considerada uma variável de médias elevadas e de Fig. 15.…”